68. Alava, JJ; Kazmiruk, TN; Douglas, T; Schuerholz, G; Heath, B; Flemming, SA; Bendell, L; Drever, MC. (2021) Occurrence and size distribution of microplastics in mudflat sediments of the Cowichan-Koksilah Estuary, Canada: A baseline for plastic particles contamination in an anthropogenic-influenced estuary.Mar. Pollut. Bull. 173 Occurrence and size distribution of microplastics in mudflat sediments of the Cowichan-Koksilah Estuary, Canada: A baseline for plastic particles contamination in an anthropogenic-influenced estuary
Microfibers; Microfragments; Polyethylene; Mudflat sediments; Sediment deposition patterns; Cowichan Estuary; British Columbia
Documenting the prevalence of microplastics in marine-coastal ecosystems serves as a first step towards understanding their impacts and risks presented to higher trophic levels. Estuaries exist at the interface between freshwater and marine systems, and provide habitats for a diverse suite of species, including shellfish, fish, and birds. We provide baseline values for estuarine mudflats using sediment samples collected at Cowichan-Koksilah Estuary in British Columbia, Canada, a biologically-rich estuary. The estuary also contains a marine shipping terminal, forestry log sort area, and input of contaminants from nearby residential and agricultural areas. Microplastics, both fragments and fibers, occurred in 93% (13/14) of sediment samples. A mean of 6.8 microfibers/kg dw (range: 0-12 microfibers/kg dw) and 7.9 microfragments/kg (range: 0-19 fragments/kg dw) occurred in individual samples, and counts of fibers and fragments were strongly correlated (r = 0.78, p = 0.008, n = 14). The abundance of microplastics tended to be higher on the north side of the estuary that receives greater inputs from upland sources relative to the south side. Size distributions of microplastic fragments and fibers were similar to sediment grain size distribution with size categories 0.063 to 0.25 mm and 0.25 to 0.6 mm being the most common for plastics and sediment, indicating the occurrence of microplastics likely followed existing depositional processes within the estuary. Microplastics in sediments were composed of a variety of polymers, including high density polyethylene (HDPE), Nylon 6/6 (polyhexamethylene adipamide), and polyethylene terephthalate-PETE (poly(1,4-cyclohexylene dimethylene terephthalate)). This study indicates that microplastics occur throughout most of the Cowichan-Koksilah Estuary, and future studies should focus on the exposure risk and potential for bioaccumulation for wildlife species that feed on the surface of intertidal mudflats. DOI PubMed
67. Cledon, M; Tremblay, LA; Griffiths, C; Fadhlaoui, M; Champeau, O; Albentosa, M; Besada, V; Fernandez, VH; McKindsey, CW; Bendell, LI; Zhang, B; Garcia-Esquivel, Z; Curiel, S; Brar, SK; Kumar, P; Laroche, O; Couture, P. (2021) Trace Metal Residues in Marine Mussels: A Global Survey.Environ. Toxicol. Chem.Trace Metal Residues in Marine Mussels: A Global Survey
Marine mussels; Mytilus; Metals; International survey; Pollution; Bioaccumulation
Pressures from anthropogenic activities are causing degradation of estuarine and coastal ecosystems around the world. Trace metals are key pollutants that are released and can partition in a range of environmental compartments, to be ultimately accumulated in exposed biota. The level of pressure varies with locations and the range and intensity of anthropogenic activities. The present study measured residues of trace metals in Mytilus mussel species collected from a range of locations around the world in areas experiencing a gradient of anthropogenic pressures that we classified as low, moderate, or high impact. The data showed no grouping/impact level when sampling sites in all countries were incorporated in the analysis, but there was significant clustering/impact level for most countries. Overall, high-impact areas were characterized by elevated concentrations of zinc, lead, nickel, and arsenic, whereas copper and silver were detected at higher concentrations in medium-impact areas. Finally, whereas most metals were found at lower concentrations in areas classified as low impact, cadmium was typically elevated in these areas. The present study provides a unique snapshot of worldwide levels of coastal metal contamination through the use of Mytilus species, a well-established marine biomonitoring tool. Environ Toxicol Chem 2021;00:1-7. (c) 2021 SETAC DOI PubMed
66.Bendell, LI; LeCadre, E; Zhou, W. (2020) Use of sediment dwelling bivalves to biomonitor plastic particle pollution in intertidal regions; A review and study.PLoS One 15 Use of sediment dwelling bivalves to biomonitor plastic particle pollution in intertidal regions; A review and study
We explore the possibility of using the varnish (Nutallia obscurata) and Manila (Venerupis philippinarum) clams as biomonitors of microplastics (MPs) pollution. A short review is first provided on the use of bivalves for biomonitoring MPs in aquatic ecosystems. From the conclusions drawn from our review we determine if the sediment dwelling varnish and Manila clam could possibly be good choices for this purpose. We sampled 8 intertidal sites located within two distinct regions of coastal British Columbia, Burrard Inlet (5 sites) and Baynes Sound (3 sites). Each intertidal region had its own particular use; within Burrard Inlet, BMP a heavily used marine park, CP, EB, J, and AP, popular local beaches, and within Baynes Sound, Met and NHB, two intertidal regions heavily exploited by the shellfish industry and RU an intertidal region with limited aquaculture activity. Microfragments were recovered from bivalves collected from all intertidal regions except for AP. Microspheres were recovered primarily from bivalves sampled from Baynes Sound at NHB where high numbers of spheres within sediments had previously been reported. BMP and Met had the highest number of particles present within individual clams which were predominantly high density polyethylene (HDPE) and a polypropylene composite (PPC). Both polymers are extensively used by the shellfish industry in all gear types, as well as in industrial and recreational marine activities. The spatial distribution of recovered MPs was indicative of the anthropogenic use of the intertidal region suggesting these bivalves, for microfragments and microspheres, may be suitable as biomonitors and could prove to be useful tools for determining whether reduction policies for plastics use are having a positive effect on their release into marine environments. DOI PubMed
65. Fernandes, S; Farzaneh, S; Bendell, LI. (2020) Abundance and distribution of beach litter with acutely toxic metal concentrations.Mar. Pollut. Bull. 159 Abundance and distribution of beach litter with acutely toxic metal concentrations
Beach litter; Plastic; Toxic metals; Hg; Cd; Pb
We determined if colour, category (e.g., food packaging) or intertidal activity could explain the occurrence of litter with acute levels of metals. Six beaches were sampled; an industrial site, a local and remote park and three beaches. Food packaging accounted for 66% of litter with acute levels of metals found in 10% of samples. Acute levels were independent of colour and category, but dependent on intertidal region and its anthropogenic use. Litter with acute levels of cadmium and lead were recovered from the industrial intertidal and high concentrations of zinc and cadmium associated with candy wrappers were found on recreational beaches. In addition to the intrinsic and extrinsic loads that litter carries, also too are memory effects, i.e., the previous use of the item carries over its trace metal burden posing extreme risks to marine ecosystems. In the managing of risk associated with beach litter, legacy contaminants need be considered. DOI PubMed
64. Moore, RC; Loseto, L; Noel, M; Etemadifar, A; Brewster, JD; MacPhee, S; Bendell, L; Ross, PS. (2020) Microplastics in beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea.Mar. Pollut. Bull. 150 Microplastics in beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea
Microplastic; Marine mammal; Beluga whale; Arctic; Beaufort Sea
Microplastics (MPs, particles < 5 mm) represent an emerging global environmental concern, having been detected in multiple aquatic species. However, very little is known about the presence of MPs in higher trophic level species, including cetaceans. We worked with community based monitors and Inuvialuit hunters from Tuktoyaktuk (Northwest Territories, Canada) to sample seven beluga whales (Delphinapterus leucas) in 2017 and 2018. Microplastics were detected in the gastrointestinal tracts in every whale. We estimate that each whale contained 18 to 147 MPs in their GI tract (average of 97 +/- 42 per individual). FTIR-spectroscopy revealed over eight plastic polymer types, with nearly half being polyester. Fibres made up 49% of MPs. The diversity of MP shapes and polymeric identities in beluga points to a complex source scenario, and ultimately raises questions regarding the significance and long-term exposure of this pollutant in this ecologically and culturally valuable species. DOI PubMed
63. Roberts, EM; Stroshein, SD; Bendell, LI. (2020) Change in sediment features and the macroinvertebrate community within an estuarine ecosystem two years post-restoration.Ecosphere 11 Change in sediment features and the macroinvertebrate community within an estuarine ecosystem two years post-restoration
estuary; macroinvertebrates; restoration ecosystem response; sediment particle size
Our objective was to assess the response of an estuarine ecosystem to restoration efforts, two years post-restoration. Sediment attributes of particle size distribution (PSD), %LOI, water content and amounts of fine wood debris (FWD), and the macroinvertebrate community were compared among three sites, two reference and the recently restored site. The restored region had been previously used as a log sorting facility. As indicated by PSD, the restored site showed signs of recovery. However, the macroinvertebrate community had still not responded to restoration efforts. Sediments of reference sites were comprised of fine sand, and the macroinvertebrate community was dominated byMacomaspp. By contrast, at the restored site, sediments were mainly comprised of silt followed by fine sand,Macomaspp. was absent, and the main macroinvertebrate wasGlycera americana, a polychaeta characteristic of disturbed regions. The restored site still contained significance amounts of FWD as compared to the two reference sites attributed to its previous use. Although still early in its recovery stage, active restoration did have a positive effect and will have likely kick started the region toward recovery and further follow-up in five years is recommended. DOI
62. Kazmiruk, TN; Kazmiruk, VD; Bendell, LI. (2018) Abundance and distribution of microplastics within surface sediments of a key shellfish growing region of Canada.PLoS One 13 Abundance and distribution of microplastics within surface sediments of a key shellfish growing region of Canada
The abundance and distribution of microplastics within 5 sediment size classes (>5000 mu m, 1000-5000 mu m, 250-1000 mu m, 250-0.63 mu m and <0.63 mu m) were determined for 16 sites within Lambert Channel and Baynes Sound, British Columbia, Canada. This region is Canada's premier growing area for the Pacific oyster (Crassostrea gigas). Microplastics were found at all sampling locations indicating widespread contamination of this region with these particles. Three types of microplastics were recovered: microbeads, which occurred in the greatest number (up to 25000/kg dry sediment) and microfibers and microfragments, which were much less in number compared with microbeads and occurred in similar amounts (100-300/kg dry sediment). Microbeads were recovered primarily in the <0.63 mu m and 250-0.63 mu m sediment size class, whereas microfragments and microfibers were generally identified in all 5 sediment size classes. Abundance and distribution of the three types of microplastics were spatially dependent with principal component analysis (PCA) indicating that 84 percent of the variation in abundance and distribution was due to the presence of high numbers of microbeads at three locations within the study region. At these sites, microbeads expressed as a percent component of the sediment by weight was similar to key geochemical components that govern trace metal behavior and availability to benthic organisms. Microbeads have been shown to accumulate metals from the aquatic environment, hence in addition to the traditional geochemical components such as silt and organic matter, microplastics also need to be considered as a sediment component that can influence trace metal geochemistry. Our findings have shown that BC's premier oyster growing region is highly contaminated with microplastics, notably microbeads. It would be prudent to assess the degree to which oysters from this region are ingesting microplastics. If so, it would have direct implications for Canada's oyster farming industry with respect to the health of the oyster and the quality of product that is being farmed and sets an example for other shellfish growing regions of the world. DOI PubMed
61. Munier, B; Bendell, LI. (2018) Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems.PLoS One 13 Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems
Nine urban intertidal regions in Burrard Inlet, Vancouver, British Columbia, Canada, were sampled for plastic debris. Debris included macro and micro plastics and originated from a wide diversity of uses ranging from personal hygiene to solar cells. Debris was characterized for its polymer through standard physiochemical characteristics, then subject to a weak acid extraction to remove the metals, zinc, copper, cadmium and lead from the polymer. Recently manufactured low density polyethylene (LDPE), nylon, polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC) were subject to the same extraction. Data was statistically analyzed by appropriate parametric and non-parametric tests when needed with significance set at P < 0.05. Polymers identified in field samples in order of abundance were; PVC (39), LDPE (28), PS (18), polyethylene (PE, 9), PP (8), nylon (8), high density polyethylene (HDPE, 7), polycarbonate (PC, 6), PET (6), polyurethane (PUR, 3) and polyoxymethylene (POM, 2). PVC and LDPE accounted for 46% of all samples. Field samples of PVC, HDPE and LDPE had significantly greater amounts of acid extracted copper and HDPE, LDPE and PUR significantly greater amounts of acid extracted zinc. PVC and LDPE had significantly greater amounts of acid extracted cadmium and PVC tended to have greater levels of acid extracted lead, significantly so for HDPE. Five of the collected items demonstrated extreme levels of acid extracted metal; greatest concentrations were 188, 6667, 698,000 and 930 mu gg(-1) of copper, zinc, lead and cadmium respectively recovered from an unidentified object comprised of PVC. Comparison of recently manufactured versus field samples indicated that recently manufactured samples had significantly greater amounts of acid extracted cadmium and zinc and field samples significantly greater amounts of acid extracted copper and lead which was primarily attributed to metal extracted from field samples of PVC. Plastic debris will affect metals within coastal ecosystems by; 1) providing a sorption site (copper and lead), notably for PVC 2) desorption from the plastic i.e., the "inherent" load (cadmium and zinc) and 3) serving as a point source of acute trace metal exposure to coastal ecosystems. All three mechanisms will put coastal ecosystems at risk to the toxic effects of these metals. DOI PubMed
60.Bendell, LI. (2015) Favored use of anti-predator netting (APN) applied for the farming of clams leads to little benefits to industry while increasing nearshore impacts and plastics pollution.Marine Pollution Bulletin 91: 22-28 Favored use of anti-predator netting (APN) applied for the farming of clams leads to little benefits to industry while increasing nearshore impacts and plastics pollution
Anti-predator netting; APN; Clam gardens; Crabs; Intertidal habitat
An overview of the efficacy of anti-predator netting (APN) used by the shellfish industry is presented. There is little support that the currently favored APN effectively protects farmed clams from predators. Evidence does suggest that APN leads to impacts and pollution. APN is an attractant for predators, e.g., crabs, by providing a refuge within Ulva sp. which attaches onto the surface of APN. APN entrains silt and organic matter and increases sediment temperatures degrading habitat underneath the APN. APN present hazards to fish and wildlife and is a source of plastics to the marine environment. The continued use of ineffective APN does not serve either the environment or industry well, and many of these issues could be addressed through the alternate use of "ancient" technology used by aboriginal people to maintain clam gardens; building of rock walls optimizing the amount of clam habitat thereby increasing numbers without the use of APN. (C) 2015 Elsevier Ltd. All rights reserved. DOI PubMed
59. Cluzard, M; Kazmiruk, TN; Kazmiruk, VD; Bendell, LI. (2015) Intertidal Concentrations of Microplastics and Their Influence on Ammonium Cycling as Related to the Shellfish Industry.Archives of Environmental Contamination and Toxicology 69: 310-319 Intertidal Concentrations of Microplastics and Their Influence on Ammonium Cycling as Related to the Shellfish Industry
Microplastics are ubiquitous within the marine environment. The last 10 years have seen research directed at understanding the fate and effect of microplastics within the marine environment; however, no studies have yet addressed how concentrations of these particles could affect sedimentary processes such as nutrient cycling. Herein we first determine the concentration and spatial distribution of microplastics within Baynes Sound, a key shellfish-growing area within coastal British Columbia (BC). We also determined sediment grain size and % organic matter (OM) such that we could relate spatial patterns in sediment microplastic concentrations to sedimentary processes that determine zones of accretion and erosion. Using field-determined concentrations of microplastics, we applied laboratory microcosms studies, which manipulated sediment concentrations of microplastics, OM, and bivalves to determine the influence of sediment microplastics on ammonium cycling within intertidal sediments. Concentrations of microplastics determined within the intertidal sediment varied spatially and were similar to those found in other coastal regions of high urban use. Concentrations were independent of grain size and OM suggesting that physical processes other than those that govern natural sediment components determine the fate of microplastics within sediments. Under laboratory conditions, concentrations of ammonium were significantly greater in the overlying water of treatments with microplastics, clams, and OM compared with treatments without microplastics. These preliminary studies suggest that high concentrations of microplastics have the potential to alter key sedimentary processes such as ammonium flux. This could have serious implications, for example, contributing to eutrophication events in regions of the coast that are highly urbanized. DOI
58. St Clair, CT; Baird, P; Ydenberg, R; Elner, R; Bendell, LI. (2015) Trace elements in pacific Dunlin (Calidris alpina pacifica): patterns of accumulation and concentrations in kidneys and feathers.Ecotoxicology 24: 29-44 Trace elements in pacific Dunlin (Calidris alpina pacifica): patterns of accumulation and concentrations in kidneys and feathers
Cadmium; Dunlin; Habitat preference; Risk assessment; Selenium; Trace elements
Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report concentrations of cadmium, copper, and zinc in kidneys as well as copper, lead, mercury, selenium and zinc in feathers. Relationships between element concentrations and Dunlin age, sex, bill length, habitat preference, trophic level, and sample group were investigated with regression analyses. Stable isotope ratios of carbon and nitrogen in Dunlin muscle tissue were used to determine habitat preference and trophic level, respectively. Cadmium concentrations in kidneys were significantly related to habitat preference: [Cd] in estuarine foragers >[Cd] in terrestrial foragers. Cadmium accumulation was age-dependent as concentrations increased significantly within 10 months of hatch dates but not afterward. Concentrations of cadmium and zinc in kidneys as well as lead and mercury in feathers were below those known to cause deleterious effects in birds. In contrast, selenium concentrations in feathers (range: 2.1-14.0 A mu g/g) were often at levels associated with toxicity risks (> 5 A mu g/g). Toxicity thresholds are not available for copper in kidneys or copper and zinc in feathers; however, measured concentrations of these elements were within documented ranges for sandpipers. Future studies should assess potential impacts of selenium on embryonic development in Dunlin and other sandpipers. Risk assessments would yield more conclusive results for all elements if impacts under ecologically relevant stresses (e.g. development in the wild, migration, predation) were better understood. DOI PubMed
57. Barlow, C; Bendell, LI; Duckham, C; Faugeroux, D; Koo, V. (2014) Three-Dimensional Profiling Reveals Trace Metal Depositional Patterns in Sediments of Urban Aquatic Environments: A Case Study in Vancouver, British Columbia, Canada.Water Air and Soil Pollution 225 Three-Dimensional Profiling Reveals Trace Metal Depositional Patterns in Sediments of Urban Aquatic Environments: A Case Study in Vancouver, British Columbia, Canada
Urban aquatic environment; Copper; Zinc; Cadmium; Sediments; Rehabilitation; Brake pads
The objectives of our study were to (1) determine the concentrations of zinc, copper, cadmium, and lead in sediments of three different aquatic environments within an urban setting, a wetland, an estuary, and a marine harbor and (2) through a comparison of the concentrations and patterns of metal deposition among the three systems, assess both the historical and current sources of these trace metals to each of these environments. Such information is essential for the proper rehabilitation of these systems. To meet these objectives, we applied a three-dimensional mapping approach which allowed us to spatially visualize the extent of metal contamination within each of the urban aquatic environments. Such an approach proved useful in identifying the tracemetal "depositional footprint" for each aquatic system. For the wetland, a creek which flowed into the wetland provided the primary source, for the estuary, the creek which fed the estuary, and a sewer outfall, and for the marine embayment, boat hull cleaning activities and two sewer outfalls were primary sources. Concentrations of metals ranged several orders of magnitude among the three aquatic systems; zinc, 2.5-709; copper, 7-3,667; lead, 4-698; and cadmium, 0.2-4.6 mu g g(-1) dry weight of sediment. The greatest range was for copper with the point source of copper-based antifouling paints contributing to the maximum concentrations determined for the three aquatic systems. All metals were significantly elevated in surficial sediments in all three ecosystems with recent accumulations of copper exceeding the probable effects level as recommended by the Canadian Council of Ministers of the Environment. It is most likely the primary source of this copper is from the abrasion of tires and brake pads. In the rehabilitation of these systems, attention will have to be paid to the dredging and proper disposal of sediments that have accumulated metals over time, especially those of copper that pose a toxicological concern to aquatic life. It is recommended that Canada as is being done in various jurisdictions in the USA as well as in Europe, pass legislation prohibiting the use of copper in brake pads. DOI
56.Bendell, LI. (2014) Evidence for Declines in the Native Leukoma staminea as a Result of the Intentional Introduction of the Non-native Venerupis philippinarum in Coastal British Columbia, Canada.Estuaries and Coasts 37: 369-380 Evidence for Declines in the Native Leukoma staminea as a Result of the Intentional Introduction of the Non-native Venerupis philippinarum in Coastal British Columbia, Canada
Mariculture; Manila clam; Littleneck clam; Invasive; Seeding
On the west coast of British Columbia (BC), Canada, the intertidal regions are under ever increasing pressure to be used primarily for near-bottom mariculture practices. These include seeding the foreshore with the nonindigenous Venerupis philippinarum (Manila clam) followed by the application of antipredator netting. The Manila is confamilial with the indigenous Leukoma staminea (littleneck clam), and seeding could possibly provide a competitive advantage for the Manila leading to the extirpation of the littleneck within coastal BC. Over two survey years, nine and seven farm-reference paired beaches (18 and 14 beaches) from three geographically distinct regions of BC were sampled for abundances and size class structure of the Manila and littleneck clam. Several lines of evidence suggest that the Manila is replacing the native littleneck; (1) comparison of average abundances of the littleneck versus Manila showed a significantly greater number of Manila on both farmed and reference sites across all three regions (p < 0.05; years I and II); (2) as distance between farmed and reference sites increased, numbers of littlenecks on reference sites also increased suggesting that close proximity to farmed sites increases the effect of seeding on numbers of the native species; (3) comparison of percent similarity of the population structure as determined by size class distribution for the Manila versus the littleneck clam indicated that intertidal reference sites in close proximity to farmed sites tended to be more similar to each other with respect to similar Manila population structure versus that of the littleneck (r = 0.4; p = 0.08); (4) within the region where active farming is the most aggressive (Baynes Sound), Manila clams are the dominant bivalve on all sampled intertidal regions; and (5) where the dispersal of "wild" (not-seeded) Manila clam is prevented because of thermal tolerance limits, the littleneck is the dominant bivalve. Ecological consequences of such species replacement on intertidal function are as yet known. DOI
55.Bendell, LI. (2014) Community composition of the intertidal in relation to the shellfish aquaculture industry in coastal British Columbia, Canada.Aquaculture 433: 384-394 Community composition of the intertidal in relation to the shellfish aquaculture industry in coastal British Columbia, Canada
Marine aquaculture; Venerupis philippinarum; Intertidal; Benthic community; Hemigrapsus oregonensis
The intertidal region of the Pacific Northwest is under ever increasing pressure to be used exclusively for the industrial sized operations of shellfish aquaculture. In British Columbia (BC), aquaculture practices include seeding the intertidal with the non-indigenous Venerupis philippinarum followed by the application of anti-predator netting. Ecological consequences of such practices applied at large scales are unknown. To assess for possible impacts 28 farm and reference sites from 3 geographically distinct regions of BC were surveyed in each of two years and their epibenthic, endobenthic and macroflora communities compared. The three regions differed in their intensity of industry from low (Barkley), medium (Desolation) to high (Baynes). Marked regional differences in intertidal community composition were observed. Of the three regions Baynes Sound, which has 101 tenures, was the most altered with the greatest numbers of the invasive species, Batillaria sp. and Hemigrapsus oregonensis. Barkley Sound, the region with the lowest industrial intensity, was characterized by Mytilus trossulus and the absence of H. oregonensis. The mid-intensity region, Desolation Sound, was characterized by Littorina scutulata and Tectura persona. Within Baynes Sound, seeding appears to be acting as an attractant for crab predators with farm sites having on average 3-fold greater numbers as compared to reference sites. Farming practices were also found to encourage growth and biofouling of the intertidal with Ulva sp. Consequences of changes in community composition in this case, an increase in the abundance of a major intertidal predator, H. oregonensis, on ecosystem functioning within these sensitive coastal areas are not known. (C) 2014 Elsevier B.V. All rights reserved. DOI
54. McCormick, J; St Clair, CT; Bendell, LI. (2014) Concentration and partitioning of metals in intertidal biofilms: implications for metal bioavailability to shorebirds.Ecotoxicology 23: 229-235 Concentration and partitioning of metals in intertidal biofilms: implications for metal bioavailability to shorebirds
Biofilm; Shorebirds; Cadmium; Zinc; Copper; Sediment; Partitioning
We compared zinc, copper and cadmium concentrations and the operationally defined geochemical partitioning of the three metals in sediments enriched with biofilm versus sediments without obvious biofilm present (reference) sampled from five locations within the Fraser River Delta, British Columbia, Canada. Two-way ANOVA's with site and biofilm (enriched or reference) as the two factors were applied to determine if metal concentrations or the partitioning of the metal was dependent on the two factors. Sediment enriched in biofilm contained greater amounts of aqua regia extracted zinc and copper and tended to have greater amounts of reducible cadmium as compared to reference sediments. By contrast, reference sediments had greater concentrations of easily reducible copper suggesting differences in speciation between the two sediment types. Greater concentrations of reducible cadmium within biofilm may provide a route of contaminant exposure to shorebirds whose diet is dependent on biofilm. DOI
53. Chan, KY; Bendell, LI. (2013) Potential effects of an invasive bivalve, Nuttallia obscurata: on select sediment attributes within the intertidal region of coastal British Columbia.Journal of Experimental Marine Biology and Ecology 444: 66-72 Potential effects of an invasive bivalve, Nuttallia obscurata: on select sediment attributes within the intertidal region of coastal British Columbia
NORTHEAST PACIFIC-OCEAN; TAPES-PHILIPPINARUM; COMMUNITY STRUCTURE; NITROGEN-CYCLE; FARMING CYCLE; MARINE; DYNAMICS; IMPACT; ESTUARY; OXYGEN
On the west coast of British Columbia, Canada, the varnish clam, Nuttallia obscurata, is a rapidly spreading invasive species that can reach high densities (i.e. 800 individuals m(-2)). A field survey (Tier I) and an in situ mesocosm density manipulation experiment (Tier II) were applied to determine the potential effects of this invasive bivalve on select sediment attributes within the intertidal zone. In situ experiments involved seeding 1 m(2) mesocosms with varnish clams at four densities; 0 (control), 200 (low), 500 (mid) and 800 (high). Sediment samples were taken 7 times over a three week period and analyzed for organic matter, ammonium and grain size (gravel, coarse silt, fine silt and silt) at three different depths, 0-3 cm (surface), 3-6 cm (intermediate) and 6-9 cm (bottom). Field surveys demonstrated that at natural densities bivalve distribution was best explained by sediment grain size. Contrary to expectations, the in situ manipulations indicated that at high densities varnish clams did not significantly increase sediment organic matter concentrations. Their ability to deposit feed and re-ingest biodeposits may have prevented accumulations. High densities of varnish clams did however result in significantly higher concentrations of sediment ammonium and percent silt, but mostly within the lower sections of the sediment core. Reworking of the surficial sediments due to intense storm activity likely obscured any differences in determined sediment attributes among the 4 treatments. Nitrogen is a limiting nutrient with ammonium preferentially used by phytoplankton and microphytobenthos. These primary producers form the basis of all marine food webs thus increases in amounts of ammonium to shallow coastal seas as a result of high densities of an invasive bivalve within intertidal zones could result in an increased risk of eutrophication within these sensitive regions. (C) 2013 Elsevier B.V. All rights reserved. DOI
52. Duckham, C; Bendell, LI. (2013) Legacy Metals Within Urban Aquatic Environments and the Challenge They Pose to Rehabilitation.Bulletin of Environmental Contamination and Toxicology 91: 396-401 Legacy Metals Within Urban Aquatic Environments and the Challenge They Pose to Rehabilitation
COMMUNITY STRUCTURE; COPPER; PAINT; ZINC
Legacy metals, a result of previous environmentally unsound practices, pose a challenge to the rehabilitation of urban aquatic ecosystems. The current study focuses on a harbor in Vancouver, British Columbia, Canada, where use of antifouling paints for hull cleaning occurred for ca. 30 years. Sediment metal concentrations were mapped by depth and distance from where hulls were cleaned. By relating metal concentrations to the benthic invertebrate community and bivalve metal content, results indicate that cleaning activities severely impacted sediment quality. However, sewer outfalls, which integrate non-point sources of metals to the harbor, also contributed to poor sediment quality and high metal concentrations in bivalves. For the aquatic system to recover, non-point diffuse metal sources must be addressed, regardless of the challenge. DOI
51.Bendell, LI. (2011) Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents.Science of the Total Environment 409 Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents
Archived samples; Gizzard; Time trend; Mining; Cadmium; Copper
Archived samples of blue grouse (Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation: however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of "pulse" toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a "snap-shot" of soil, plant or avian tissue trace metal analysis post-mining activity. (C) 2010 Elsevier B.V. All rights reserved. DOI
50.Bendell, LI. (2011) Sea ducks and aquaculture: the cadmium connection.Ecotoxicology 20 Sea ducks and aquaculture: the cadmium connection
Sea ducks; Aquaculture; Blue mussel; Surf scoter; Cadmium; Toxicity
Elevated concentrations of cadmium have been reported in the kidneys of sea ducks that forage along the Pacific Northwest, and cadmium has been postulated as a possible cause of population declines. The blue mussel (Mytilus spp.) which occurs in dense numbers on aquaculture structures and are a primary prey item for sea ducks also contain elevated cadmium concentrations. To determine if foraging on mussels associated with aquaculture structures could pose a toxicological risk to sea ducks, amounts of cadmium ingested per body weight per day by a representative sea duck species, the surf scoter (Melanitta perspicillata), were estimated and compared to the reported avian cadmium NOAEL (no observable adverse effect level) and LOAEL (lowest observable adverse effect level). Results indicate that in some locations within the Pacific Northwest, sea ducks could be exposed to toxicologically significant levels of cadmium associated with mussels foraged from aquaculture structures. This raises the possibility that such exposure could be contributing to observed population declines in these species. DOI
49.Bendell, LI; Wan, PCY. (2011) Application of aerial photography in combination with GIS for coastal management at small spatial scales: a case study of shellfish aquaculture.Journal of Coastal Conservation 15: 417-431 Application of aerial photography in combination with GIS for coastal management at small spatial scales: a case study of shellfish aquaculture
Aerial photography; GIS; Spatial analysis; Cumulative affects; Anthropogenic footprint
Coastal zones are among the planets most threatened ecosystems and effective management of these systems requires spatial tools at appropriate spatial scales. Here we apply aerial photography with Geographic Information Systems (GIS), to map the cumulative anthropogenic footprint of an industry in a spatially defined ecologically important region of the British Columbian coast. Resolution required for such an analysis was made possible through highly detailed aerial photography of the region taken at an elevation of 305 m, at a 1:3000 scale. The approach applied here was successful in accurately detailing the cumulative extent of the anthropogenic activity on the foreshore which could have not been achieved at a coarser resolution. Such information was then effectively applied to visualize and assess the potential impact of an industrial development of the foreshore on bird distribution within the spatially identified region. The degree of overlap between the anthropogenic footprint and small estuaries within the region was also successfully assessed. For ecologically important regions such as Marine Protected Areas, and other such designated sensitive coastal regions, detailed mapping through aerial photography and GIS can aid in first identifying the true extent of an anthropogenic activity and then secondly used to link to possible ecological consequences. This in turn greatly enhances our ability to best manage the region of interest such that conservation priorities can be met. DOI
48. Brunham, W; Bendell, LI. (2011) The Effect of Temperature on the Accumulation of Cadmium, Copper, Zinc, and Lead by Scirpus acutus and Typha latifolia: A Comparative Analysis.Water Air and Soil Pollution 219: 417-428 The Effect of Temperature on the Accumulation of Cadmium, Copper, Zinc, and Lead by Scirpus acutus and Typha latifolia: A Comparative Analysis
Metal accumulation; Typha latifolia; Scirpus acutus; Temperature; Marsh; Wetland; Phytoremediation
Wetland plants have a capacity for metal sequestration and have been used to remediate such environmental contaminants. How this capacity will be affected by a warming environment is not well-known. Our objective was to identify the effect of small environmentally realistic increases in temperature on metal (cadmium, zinc, lead, and copper) accumulation in Typha latifolia as compared with Scirpus acutus. These common wetland plant species were grown in metal-contaminated sediments at 13A degrees C, 16A degrees C, and 18A degrees C for 3 months to determine the effect of environmentally realistic temperatures on metal accumulation. Cd(109) was used as a radiotracer to study the effect of temperature on uptake kinetics. Growth of the two wetland plants differed markedly; S. acutus displayed linear growth reaching a maximum height of ca. 100 cm; by contrast, T. latifolia grew to ca. 40 cm by day 60 with no further growth occurring over the remainder of the 105-day growth period. S. acutus accumulated more cadmium, lead, and zinc from contaminated sediments than T. latifolia, but only within roots and rhizomes. Although not significant, uptake of cadmium, lead, and zinc by both plants was enhanced under warmer conditions and was most pronounced in S. acutus. This was supported by the radiotracer studies which indicated that under the higher temperatures, there was increased rates of Cd(109) uptake by shoots of S. acutus. By contrast, temperature did not affect Cd(109) uptake rate constants in T. latifolia. S. acutus appears to be more effective at sequestering metals from contaminated sediments; this species as compared to T. latifolia may also be more affected by a warming climate. In the design of wetlands for metal remediation, differences in how these two plants sequester metals from their environment should be considered. DOI
47.Bendell, LI. (2010) Cadmium in shellfish: The British Columbia, Canada experience-A mini-review.Toxicology Letters 198: 7-12 Cadmium in shellfish: The British Columbia, Canada experience-A mini-review
Cadmium; Shellfish; Oysters; Risk assessment; First Nations
Over 10 years ago, research scientists in the federal department of Fisheries and Oceans Canada (DFO) were alerted to the presence of high levels of cadmium, a toxic metal, in the Pacific oyster (Crassostrea gigas) cultured in British Columbia (BC), Canada waters. This mini-review summarizes the most recent published studies on levels of cadmium in shellfish from the Pacific Northwest (BC and Washington State). Recent health risk assessments with respect to the ingestion of BC oysters are presented. The review concludes with a discussion on the ethical dilemma now facing the shellfish industry in the Pacific Northwest and provides recommendations for the culturing of shellfish without fear of high cadmium levels. (c) 2010 Elsevier Ireland Ltd. All rights reserved. DOI
46.Bendell, LI; Duckham, C; L'Espérance, T; Whiteley, JA. (2010) Changes in geochemical foreshore attributes as a consequence of intertidal shellfish aquaculture: a case study.Marine Ecology-Progress Series 404: 91-108 Changes in geochemical foreshore attributes as a consequence of intertidal shellfish aquaculture: a case study
Intertidal; Community composition; Shellfish aquaculture; Nutrients; Organic matter; Nitrogen; Phosphorous; Iron
On the west coast of British Columbia (BC), Canada, the intertidal is under pressure by commercial farming of the non-native Manila clam Venerupis philippinarum. We applied a 3-tiered approach to determine how farming practices were affecting the geochemical attributes of the intertidal. We compared farmed and reference sites with respect to % silt, organic matter, ammonium, phosphorus, iron and manganese in surface (0 to 3 cm) and bulk (0 to 10 cm) sediments. Ammonium porewater profiles and sediment sorption coefficients were determined for 1 of the 3 regions where the greatest intensity of shellfish farming occurred (Tier I). Mesocosm studies were conducted in which intertidal species were manipulated to match the community composition on the farmed as compared to reference sites (Tier II). Microcosm studies were applied to determine how shifts in community structure as observed on farmed versus reference sites and as manipulated in the mesocosm studies, altered the rate of ammonium diffusion to overlying surface waters (Tier III). All geochemical attributes and ammonium sorption coefficients were greater in either surficial and/or bulk sediments of farmed as compared to reference beaches. Tier III studies indicated that the rate of ammonium diffusion from sediments to surface waters was less in microcosms with only bivalves compared to those with mussels, barnacles and bivalves. Tier I and II studies suggest that greater recovery of ammonium and phosphorus is related to increased bivalve density and % plant coverage on farmed versus reference sites. In contrast, greater amounts of organic matter and silt are due to the presence of antipredator nets. Farming practices that ensure well aerated sediments and support a diverse intertidal community would be advised so that important nutrient geochemical cycles are not altered such to be a detriment to the quality of habitat or to interfere with primary productivity. DOI
45. Cook, N; Bendell-Young, L. (2010) DETERMINING THE ECOLOGICAL ROLE OF EUSPIRA LEWISII: PART I: FEEDING ECOLOGY.Journal of Shellfish Research 29: 223-232 DETERMINING THE ECOLOGICAL ROLE OF EUSPIRA LEWISII: PART I: FEEDING ECOLOGY
British Columbia; community impacts; gastropod; Euspira feeding ecology; shellfish aquaculture
The predatory naticid snail Euspira Lewisii, Lewis' moon snail, native to the west coast of North America, is stated to be an economic threat to the shellfish aquaculture industry in British Columbia (BC). This species is being manually removed from the intertidal ecosystem, yet little is known about the ecology of this species. Enclosures and beach shell assemblages were used to determine the prey preference, feeding rates, and community impacts of E. lewisii. In the enclosures. Protothaca staminea, the native little neck clam, was found to be the preferred prey, whereas the commercially valuable Manila clam, Venerupis philippinarum, was avoided when E. lewisii was offered other clam prey choices. Drilled shells collected from the intertidal revealed similar feeding preferences. The feeding rate averaged for a variety of clam species was found to be 0.09 clams/day or 1 clam every 14 days. The feeding rate was dependent on prey species, and was highest for the preferred species and significantly lower on avoided species. The overall impact of E. lewisii to the bivalve community was found to be low. Based on these results, E. lewisii consumed only approximately 3% of the clam population over 1 y, assuming maximal feeding rates and typical population densities found on the west coast of BC. E. lewisii has minimal impacts to the Manila clam industry in BC and control measures are not necessary for this species. Baseline ecological field studies are important for gaining an understanding of poorly understood species, especially those considered threats to industry.
44. Feng, CX; Cao, JG; Bendell, L. (2010) Exploring Spatial and Temporal Variations of Cadmium Concentrations in Pacific Oysters from British Columbia.Biometrics 67: 1142-1152 Exploring Spatial and Temporal Variations of Cadmium Concentrations in Pacific Oysters from British Columbia
Cadmium concentration; Functional principal component analysis; Monotone smoothing; Semi-parametric additive model
Oysters from the Pacific Northwest coast of British Columbia, Canada, contain high levels of cadmium, in some cases exceeding some international food safety guidelines. A primary goal of this article is the investigation of the spatial and temporal variation in cadmium concentrations for oysters sampled from coastal British Columbia. Such information is important so that recommendations can be made as to where and when oysters can be cultured such that accumulation of cadmium within these oysters is minimized. Some modern statistical methods are applied to achieve this goal, including monotone spline smoothing, functional principal component analysis, and semi-parametric additive modeling. Oyster growth rates are estimated as the first derivatives of the monotone smoothing growth curves. Some important patterns in cadmium accumulation by oysters are observed. For example, most inland regions tend to have a higher level of cadmium concentration than most coastal regions, so more caution needs to be taken for shellfish aquaculture practices occurring in the inland regions. The semi-parametric additive modeling shows that oyster cadmium concentration decreases with oyster length, and oysters sampled at 7 m have higher average cadmium concentration than those sampled at 1 m. DOI PubMed
43.Bendell, LI. (2009) Survey of levels of cadmium in oysters, mussels, clams and scallops from the Pacific Northwest coast of Canada.Food Additives & Contaminants Part B-Surveillance 2: 131-139 Survey of levels of cadmium in oysters, mussels, clams and scallops from the Pacific Northwest coast of Canada
CRASSOSTREA-GIGAS; CULTURED OYSTERS; SHELLFISH; ACCUMULATION; MERCURY; FISH; LEAD
Field and retail collections of bivalves from the Pacific Northwest, Canada, were analysed for cadmium concentrations by atomic absorption spectrophotometry (AAS). Both collections of varnish (Nuttallia obscurata) and manila (Venerupis philippinarum) clams contained cadmium concentrations of less than 0.5 mu g g(-1), well below international safety guidelines of 1 and 2 mu g g(-1) wet weight cadmium for the European and Hong Kong markets, respectively, as well as the 2 mu g g(-1) safety guideline set by the Codex Alimentarius Commission (CAC). Cadmium concentrations in retail collections of the Pacific oyster, Crassostrea gigas, were generally above 2 mu g g(-1) wet weight (range = 1.5-3.56 mu g g(-1)). Retail collections of the mussel, Mytilus spp., contained cadmium concentrations below the 2 mu g g(-1) wet weight guideline, but not always the 1 mu g g(-1) limit (range 0.15-1.8 mu g g(-1)). However, field collections of Mytilus spp. contained cadmium concentrations between 0.35 and 4.00 mu g g(-1) wet weight, and depending on sampling location, concentrations exceeded the CAC guidelines by more than two-fold. Locations where mussels had high cadmium concentrations correlated with regions that had previously reported high values for cadmium in Pacific oysters (r = 0.65; p < 0.05). Of the various shellfish analysed, the four species of scallops, Chlamys hastata, C. rubida, Crassadoma gigantea, and Patinopecten yessoensis, contained the greatest concentrations of cadmium, in excess of 5 mu g g(-1) wet weight (range 4.97-8.98 mu g g(-1)) with the greatest concentrations determined for C. gigantea. Cadmium concentrations in shellfish from the Pacific Northwest are greater than values reported for shellfish from other regions of the world and consumers need be aware of Health Canada consumption guidelines for shellfish from this region. DOI
42.Bendell, LI; Feng, C. (2009) Spatial and temporal variations in cadmium concentrations and burdens in the Pacific oyster (Crassostrea gigas) sampled from the Pacific north-west.Marine Pollution Bulletin 58: 1137-1143 Spatial and temporal variations in cadmium concentrations and burdens in the Pacific oyster (Crassostrea gigas) sampled from the Pacific north-west
WEIGHT; ZINC
Oysters from the north-west coast of Canada contain high levels of cadmium, a toxic metal, in amounts that exceed food safety guidelines for international markets. A first required step to determine the sources of cadmium is to identify possible spatial and temporal trends in the accumulation of cadmium by the oyster. To meet this objective, rather than sample wild and cultured oysters of unknown age and origin, an oyster "grow-out" experiment was initiated. Cultured oyster seed was suspended in the water column up to a depth of 7 m and the oyster seed allowed to mature a period of 3 years until market size. Oysters were sampled bimonthly and at time of sampling, temperature, chlorophyll-a, turbidity and salinity were measured. Oyster total shell length, dry tissue weights, cadmium concentrations (mu g g(-1)) and burdens (mu g of cadmium oyster(-1)) were determined. Oyster cadmium concentrations and burdens were then interpreted with respect to the spatial and temporal sampling design as well as to the measured physio-chemical and biotic variables. When expressed as a concentration, there was a marked seasonality with concentrations being greater in winter as compared in summer; however no spatial trend was evident. When expressed as a burden which corrects for differences in tissue mass, there was no seasonality, however cadmium oyster burdens increased from south to north. Comparison of cadmium accumulation rates oyster(-1) among sites indicated three locations, Webster Island, on the west side of Vancouver Island, and two within Desolation Sound, Teakerne Arm and Redonda Bay, where point sources of cadmium which are not present at all other sampling locations may be contributing to overall oyster cadmium burdens. Of the four physio-chemical factors measured only temperature and turbidity weakly correlated with tissue cadmium concentrations (r(2) = -0.13; p < 0.05). By expressing oyster cadmium both as concentration and burden, regional and temporal patterns were demonstrated, which may have been missed if just concentration was determined. (C) 2009 Elsevier Ltd. All rights reserved. DOI
41. Christie, JC; Bendell, LI. (2009) Sources of dietary cadmium to the Pacific oyster Crassostrea gigas.Marine Environmental Research 68: 97-105 Sources of dietary cadmium to the Pacific oyster Crassostrea gigas
SUSPENSION-FEEDING BIVALVE; NITROGEN STABLE-ISOTOPES; MARENNES-OLERON BAY; FOOD SOURCES; ORGANIC-MATTER; CULTURED OYSTERS; TRACE-ELEMENTS; MARINE; CARBON; WATER
Oysters from the Pacific north-west coast contain high cadmium concentrations (greater than 13.5 mu g g(-1) dry weight), which exceed consumer guidelines for international markets. Oysters are selective filter-feeders and attempts which have focused on suspended particulate matter (SPM) as a means to assess the importance of diet as a route of cadmium exposure have met with limited success. Here we use actual gut contents as an alternate to SPM to assess if this is a better predictor of cadmium exposure to the oyster via the diet. We also applied stable isotope analysis, delta C-13 and delta N-15, to determine the origin of organic material (from terrestrial to oceanic) ingested by the oyster. Oyster gut and tissue cadmium concentrations and corresponding isotopic signatures were determined every 2-3 months for 22 months from 10 locations on the west coast of B.C. Gut and tissue cadmium concentrations were correlated (r(2) = 0.40: p < 0.05), suggesting that diet could account for at least 40% of observed cadmium oysters residues. Oyster gut and tissue cadmium concentrations and delta C-13 and delta N-15 signatures were region dependent. Oysters from the most marine influenced sites contained gut and tissue cadmium residues of 30.4 +/- 3.08 (S.E.) mu g g(-1) and 6.0 0.6 mu g g(-1), respectively, and a stable isotopic signature typical of marine phytoplankton. In contrast, oysters sampled from regions influenced by coastal processes contained significantly greater concentrations of cadmium, 43.0 +/- 2.4 mu g g(-1) and 10.2 +/- 0.68 mu g g(-1) gut and tissue, respectively, with isotopic signatures representative of terrestrial organic matter. This indicates that diet is an important source of cadmium to oysters from the Pacific north-west, however its importance is region dependent and cannot be simply ascribed to one source of organic matter alone. (C) 2009 Elsevier Ltd. All rights reserved. DOI
40. Widmeyer, JR; Bendell-Young, LI. (2008) Heavy metal levels in suspended sediments, Crassostrea gigas, and the risk to humans.Archives of Environmental Contamination and Toxicology 55: 442-450 Heavy metal levels in suspended sediments, Crassostrea gigas, and the risk to humans
Wild Pacific oyster (Crassostrea gigas) and sediment, both resuspended and suspended (RSS) samples (< 53 mu m), were collected over an 8-month period from a coastal estuary in Baynes Sound, BC, Canada. Stable isotope analysis (delta C-13, delta N-15) was used to determine, first, if RSS sediments was an important dietary source to C. gigas and, second, if so, whether it served as a significant dietary exposure route for Cd, Cu, Pb, and Zn. Although RSS sediments were high in trace metals such as Cd, Pb, Zn, and notably Cu, stable isotope signatures for oyster tissues did not correspond to those of RSS sediments. These results indicate that RSS sediments are not a significant source of metal to the oysters. In addition, we compared the potential risk to humans ingesting C. gigas with levels of Cd, Cu, Pb, and Zn from this study to the current Agency for Toxic Substances and Disease Registry (ATSDR) chronic oral minimal risk levels (MRLs) using current Canadian consumption guidelines of three oysters/week. Cu, Pb, and Zn levels were below MRL levels, with Cd exceeding the recommended 0.2 mu g/kg/day MRL level fourfold. Total daily intake levels (TDI) for Cd were additionally calculated and either reached or exceeded the Food and Agriculture Organization/World Health Organization (FAP/WHO) reference dose of 1 mu g/kg/day for Cd consumption in Canadians. Our results indicate that the current Canadian Cd consumption guidelines do not protect individuals consuming the maximum recommended levels of wild oysters. DOI
39. Whiteley, J; Bendell-Young, L. (2007) Ecological implications of intertidal mariculture: observed differences in bivalve community structure between farm and reference sites.Journal of Applied Ecology 44: 495-505 Ecological implications of intertidal mariculture: observed differences in bivalve community structure between farm and reference sites
bivalves; clam aquaculture; community structure; predator exclusion; Venerupis philippinarum
1. Despite recent growth in shellfish aquaculture in British Columbia, Canada, the impacts of common practices on non-target species are poorly understood. Two practices employed on clam farms to increase production of the exotic clam Venerupis philippinarum include the addition of juvenile 'seed' clams to the sediment and covering seeded clam beds with protective netting, ostensibly to exclude large mobile epibenthic predators. 2. We expected the effects of predator exclusion to be most evident among other bivalves, which made up more than 80% of the infaunal macrobenthos at all sites surveyed. A field study across three regions collected infaunal bivalve density and biomass data. We compared species richness, composition and abundances of communities between clam farms and reference sites, paired on the basis of physical characteristics such as sediment type, slope and aspect. 3. Venerupis philippinarum was the only species found in higher abundance on farm sites in low intertidal areas (227 +/- 241.6 clams m(-2), P = 0.02; 872.9 +/- 792.9 g m(-2), P = 0.037). Farmed sites showed no difference in mid-intertidal areas, nor in density of the other 25 bivalve species, although an increase would be expected if netting excluded important predators. Although statistically non-significant, there were indications that biomass of species other than V. philippinarum may have been lower on farm sites. 4. Bivalve species composition was not significantly different between farm and reference sites. Nevertheless, farm sites were more similar to each other as a group than reference sites, leading to a loss of regional distinctness that was evident among reference sites. 5. Synthesis and applications. Our findings support the hypothesis that predation and competition play minor roles in structuring communities in soft-bottomed environments. Given the potential for cumulative effects of seeding and netting at large scales, a precautionary approach is recommended in future development of intertidal clam aquaculture.PDF DOI
38. Widmeyer, JR; Bendell-Young, LI. (2007) Influence of food quality and salinity on dietary cadmium availability in Mytilus trossulus.Aquatic Toxicology 81: 144-151 Influence of food quality and salinity on dietary cadmium availability in Mytilus trossulus
dietary assimilation; bivalves; cadmium; salinity; Sediments; phytoplankton
Surficial sediments (a combination of re-suspended and suspended sediments denoted as RSS) were collected from two distinct marine intertidal habitats. The two habitats differed with respect to salinity (25 ppt versus 15 ppt) and RSS % organic carbon content (24% versus 15%). Feeding experiments were conducted simulating the conditions in the two habitats to determine if salinity and RSS % organic carbon content affected cadmium accumulation in the pacific blue mussel Mytilus trossulus. Eleven different treatments including pure phytoplankton, collected RSS and control clay were radiolabeled with Cd-109 and pulse-fed to M. trossulus under both high (25 ppt) and low salinities (15 ppt). Metal uptake and accumulation was determined using the DYMBAM biodynamic metal bioaccumulation model. Although M. trossulus ingestion rates (IR) were significantly higher at 25 ppt as compared to 15 ppt, assimilation efficiencies (AEs) and [Cd-109] tissue levels were significantly lower at high as compared to low salinity exposures. Of the abiotic and biotic parameters examined and in contrast to other studies, differences in salinity rather than ingestion rate or food quality (as defined by % organic carbon content) seemed to best define the observed differences in Cd-109 AE by M. trossulus. (c) 2006 Elsevier B.V. All rights reserved. DOI
37.Bendell-Young, LI. (2006) Contrasting the community structure and select geochemical characteristics of three intertidal regions in relation to shellfish farming.Environ Conserv 33: 21-27 Contrasting the community structure and select geochemical characteristics of three intertidal regions in relation to shellfish farming
aquaculture; biodiversity; ecological impacts; shellfish
Little is known about the impacts of intensive shellfish farming on intertidal ecosystems. To assess such impacts, several indices of ecosystem structure and select geochemical characteristics were contrasted among three intertidal regions, which represented a gradient of shellfish farming activities, namely (1) no active aquaculture, (2) actively farmed for three years and (3) actively farmed for five years. All three intertidal regions were located in Baynes Sound (British Columbia, Canada) and were geographically similar. Among the three beaches, species richness, community composition, bivalve abundance, biomass, distribution, and composition and surficial sediment per cent organic matter (carbon) and silt were compared. The intertidal regions that had been used for farming for three and five years had lower species richness, different bivalve composition, abundance and distributions, and a foreshore community dominated by bivalves, as compared to the intertidal region where no active farming occurred. Beaches that were actively farmed also had greater accumulations of organic matter and silt. Simplification of the intertidal benthic community, coupled with accumulations of organic matter and increased siltation, may have altered the ecology of the foreshore region used for intense shellfish harvesting. To access the foreshore for shellfish farming in a sustainable manner, studies are needed to determine the scale to which intensive use of the foreshore for shellfish purposes alone is feasible without undue harm to the environment.
36.Bendell, JI; Bendell-Young, LI. (2006) Eggs of spruce grouse dry at a faster rate than those of ruffed grouse.Canadian Journal of Zoology-Revue Canadienne de Zoologie 84(11): 1688-1692 Eggs of spruce grouse dry at a faster rate than those of ruffed grouse
We measured the rate of water loss and pore density of eggs of spruce grouse (Canachites canadensis canace (L., 1766)) and ruffed grouse (Bonasa umbellus togata (L., 1766)) from different parts of their range in Ontario. Eggs were dried in enclosed glass jars over Drierite® and in paper trays in open air at room temperature and humidity. Eggs were weighed to the nearest 0.01 g every 2-4 days and the change in mass was measured as water loss. Pores of shells were counted (pores/cm2) in the blunt, middle, and pointed sections of the egg. Eggs of spruce grouse lost water at a faster rate in Drierite® and in open air and had a greater density of pores than eggs of ruffed grouse. Rates of water loss were constant and varied inversely with ambient humidity, with the difference between species greatest in open air. Eggs late in incubation of ruffed grouse dried at a faster rate than those early in incubation in Drierite®. The adaptations of eggs of each grouse to the moisture of the nest may help explain their distribution, density, and habitat and nest-site selections, as well as behavioural aspects of the nesting hen. Both, especially the spruce grouse, may be good indictors of climate change.PDF
34. Gurney, KE; Williams, TD; Smits, JE; Wayland, M; Trudeau, S; Bendell-Young, LI. (2005) Impact of oil-sands based wetlands on the growth of mallard (Anas platyrhynchos) ducklings.Environmental Toxicology and Chemistry 24: 457-463 Impact of oil-sands based wetlands on the growth of mallard (Anas platyrhynchos) ducklings
Anas platyrhynchos; duckling; wetlands; ecotoxicology
Identifying the potential effects of industrially formed wetlands on waterfowl populations is important for assessing the suitability of such wetlands in industrial reclamation strategies. Mallard ducklings were held in situ on two industrially formed wetlands and one reference wetland in northern Alberta, Canada. Duckling mass and skeletal size were measured at regular intervals over 33 d, and blood was collected to investigate the analysis of plasma metabolites (triglyceride and glycerol) as an indicator of physiological condition. In repeated-measures analysis of variance (ANOVA), multivariate ANOVA, and subsequent multiple-comparisons tests, body mass and skeletal size were significantly lower in ducklings maintained on the industrial wetland after 2, 5, 9, and 13 d of exposure. In this situation, plasma metabolite analysis did not provide additional information on mass-independent condition. We conclude that if the observed differences in growth and size translate into a decreased survival of juvenile waterfowl inhabiting these wetlands, then populations of these birds in the area could be negatively affected. We emphasize the importance of field-based ecological research in toxicological studies of wildlife.
33. Morrissey, CA; Bendell-Young, LI; Elliott, JE. (2005) Identifying sources and biomagnification of persistent organic contaminants in biota from mountain streams of southwestern British Columbia, Canada.Environmental Science & Technology 39: 8090-8098 Identifying sources and biomagnification of persistent organic contaminants in biota from mountain streams of southwestern British Columbia, Canada
We assessed whether biota occupying mountain streams accumulate and biomagnify remotely derived organic pollutants originating from atmospheric inputs to snowpack and glacial runoff and from marine sources introduced by migrating anadromous salmon. Several persistent organic pollutants including polychlorinated biphenyls (PCBs), p,p'-dichloro-diphenyl-dichloroethylene, hexachlorobenzene, and trans-nonachlor were commonly detected in benthic invertebrates, salmon fry (Oncorhynchus spp.), and eggs of an aquatic passerine, the American dipper (Cinclus mexicanus) from the Chilliwack River watershed, British Columbia, Canada. Total PCBs and several organochlorines (M) biomagnified from benthic invertebrate composites to salmon fry to dipper eggs. Invertebrate samples generally did not differ significantly in contaminant burdens between the river main stem where salmon are more abundant and higher-elevation tributaries where the salmon density is lower. Concentrations of total OCs and total PCBs in dipper eggs were positively related to drainage basin area and collection year but not to elevation. No differences in PCB congener patterns existed between dipper egg samples from the Chilliwack watershed and other watersheds in southwestern British Columbia. However, principal component analysis revealed significant spatial differences in egg PCB congener patterns between the main Chilliwack River and the higher-elevation tributaries. This difference was primarily due to a greater occurrence of lower chlorinated PCB congeners (66 and 105) in dipper eggs collected from the tributaries and higher loadings of the more stable and persistent congeners (153, 138, 130, and 128) in eggs from the river main stem. The results suggest that atmospheric sources are the main contributor of contaminants detected in biota from the region and that biomagnification is a common pathway for accumulation in lotic predators such as the American dipper.
32. Morrissey, CA; Bendell-Young, LI; Elliotti, JE. (2005) Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, Canada.Environmental Toxicology and Chemistry 24: 836-845 Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, Canada
metals; feathers; feces; American dipper; ecological risk assessment
To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to metals for resident dippers that occupy the main river year-round and altitudinal migrants that breed on higher elevation tributaries because of differences in prey metal levels between locations or possible differences in diet composition. Metals most commonly detected in dipper feather samples in decreasing order were Zn > Cu > Hg > Se > Pb > Mn > Cd > Al > As. Resident dipper feathers contained significantly higher mean concentrations of mercury (0.64 mu g/g dry wt), cadmium (0.19 mu g/g dry wt), and copper (10.8 mu g/g dry wt) relative to migrants. Mass balance models used to predict daily metal exposure for dippers with different diets and breeding locations within a watershed showed that variation in metal levels primarily was attributed to differences in the proportion of fish and invertebrates in the diet of residents and migrants. In comparing predicted metal exposure values to tolerable daily intakes (TDI), we found that most metals were below or within the range of TDI, except selenium, aluminum, and zinc. Other metals, such as cadmium, copper, and arsenic, were only of concern for dippers mainly feeding on insects; mercury was only of concern for dippers consuming high fish diets. The models were useful tools to demonstrate how shifts in diet and breeding location within a single watershed can result in changes in exposure that may be of toxicological significance.
31.Bendell-Young, LI; Arifin, Z. (2004) Application of a kinetic model to demonstrate how selective feeding could alter the amount of cadmium accumulated by the blue mussel (Mytilus trossolus).Journal of Experimental Marine Biology and Ecology 298: 21-33 Application of a kinetic model to demonstrate how selective feeding could alter the amount of cadmium accumulated by the blue mussel (<i>Mytilus trossolus</i>)
metal accumulation; feeding behaviour; sorting efficiency; pseudofeces production; Cd; bivalve
Filter-feeding bivalves are well adapted to a changing food environment, capable of a highly selective feeding strategy. This feeding behaviour results in the rejection of unwanted material as pseudofeces. To assess the importance of a selective feeding behaviour performed by filter-feeding bivalves in influencing amounts of metal accumulated by bivalves, we applied a kinetic model of metal accumulation modified to incorporate feeding behaviour defined as (1) the sorting efficiency (SEF; the ability of the mussel to select organic matter (OM) over inorganic matter (IM) from suspended particulate matter (SPM) cleared from the water column) and (2) rate of rejection of unwanted SPM as pseudofeces (PF). Predicted mussel Cd concentrations (Cd-muss) were compared with Cd-muss predicted without incorporating feeding behaviour as well as to observed Cd-muss. SEF was important at an SPM quality greater than 10% OM; PF production was important at an SPM quantity greater than 3.5 mg l(-1) with the influence of PF production on predicted Cd-muss increasing with increasing SPM concentration. Our results suggest that a selective feeding behaviour and the generation of pseudofeces could influence amounts of metal ingested, especially under conditions where SPM quality and quantity are highly variable. Under conditions of high SPM, the influence of SEF and PF production on final Cd-muss should be taken into consideration. (C) 2003 Elsevier B.V All rights reserved.
30. Jurgensen, A; Widmeyer, JR; Gordon, RA; Bendell-Young, LI; Moore, MM; Crozier, ED. (2004) The structure of the manganese oxide on the sheath of the bacterium Leptothrix discophora: An XAFS study.American Mineralogist 89: 1110-1118 The structure of the manganese oxide on the sheath of the bacterium <i>Leptothrix discophora</i>: An XAFS study
In natural waters, manganese oxides (MnOx) are important in mediating the bioavailability of trace metals such as Ni, Cu, Zn, Cd, and Pb, as these metals readily adsorb to the MnOx surface. Manganese from a variety of anthropogenic sources usually enters the aquatic environment in dissolved form as Mn-2divided by. It is subsequently oxidized under oxic and neutral (pH = 6-7) conditions. Often this oxidation is catalyzed by bacteria, such as Leptothrix discophora, as part of their natural metabolic process. Mn K-edge X-ray Absorption Fine Structure Spectroscopy (XAFS) was used to investigate the local structure of manganese oxide on the sheath produced by the bacterium Leptothrix discophora SP-6. The features observed in the near edge region of the Mn K-edge spectrum indicate the presence of three oxidation states of manganese: Mn-2divided by, Mn-3divided by, and Mn-4divided by. Fitting the experimental XAFS data identifies the bacterial MnOx as being composed of single-layer microcrystals with layers similar to those occurring in Na-birnessite. Some MnO6 octahedra might lie outside the layer plane, sharing corners with those in the layer plane. X-ray diffraction results for the same samples are consistent with the single-layer structure.
29. Morrissey, CA; Bendell-Young, LI; Elliott, JE. (2004) Seasonal trends in population density, distribution, and movement of American Dippers within a watershed of southwestern British Columbia, Canada.Condor 106: 815-825 Seasonal trends in population density, distribution, and movement of American Dippers within a watershed of southwestern British Columbia, Canada
altitudinal migration; American Dipper; Cinclus mexicanus; indicator species; mark-recapture; radio-telemetry; watershed
American Dippers concentrate on low-elevation streams during fall and winter in many parts of their range; however the breeding origin relative to the wintering location is poorly understood. Our objectives were to identify seasonal changes in the density and distribution of American Dippers, to classify the migratory behavior of the local population, and to determine the origin of winter migrants within a coastal watershed of British Columbia, Canada. During 1999-2002, we color banded 522 dippers and radio-tagged 14 in the Chilliwack River watershed. Using mark-resighting techniques, we identified peak densities on the main river during early November (9.8 +/- 1.4 [SE] birds per stream km), which was nearly 5 times higher than in early July (2.1 +/- 0.3 birds per stream km). The watershed's total population size, estimated from November surveys, was 429 +/- 64 [SE] dippers in 1999, 682 +/- 79 in 2000, 697 +/- 123 in 2001, and 550 +/- 72 in 2002. The majority (79-90%) of the dipper population seasonally migrated, primarily moving from the main river in fall and winter to the higher-elevation tributaries in spring. The remaining dippers (10-16%) remained resident on the main river year-round. Migrants showed a high degree of winter site fidelity with 67% returning to the same site on the Chilliwack River for 2 or more years. Given the population's defined structure and predictable seasonal movements, this study has implications for applying American Dipper populations as indicators of water and habitat quality in North American watersheds.
28. Morrissey, CA; Bendell-Young, LI; Elliott, JE. (2004) Linking contaminant profiles to the diet and breeding location of American dippers using stable isotopes.Journal of Applied Ecology 41: 502-512 Linking contaminant profiles to the diet and breeding location of American dippers using stable isotopes
biomonitor; mercury; (15)Nitrogen; organochlorines; PCB; rivers; salmon fry; selenium
1. Individual variation in contaminant levels is a common occurrence in many toxicology studies, but the exact cause is often unclear. We investigated the influence of diet and breeding location on individual bird contaminant profiles using a colour-marked population of American dippers Cinclus mexicanus. The population comprised two distinct groups within a single river system: resident dippers breeding on the main river and altitudinal migrants breeding on tributaries. 2. Residue analysis revealed that total organochlorines (OC), polychlorinated biphenyls (PCB) and mercury (Hg) were all significantly higher in eggs from river residents compared with tributary migrants. This trend was also apparent for the three most prevalent organochlorine compounds: p,p'-dichlorodiphenyl-dichloroethylene (DDE), hexachlorobenzene and trans-nonachlor. 3. We hypothesized that the observed differences in contaminant concentrations were partially related to the proportion of salmon fry Oncorhynchus spp. in the diet relative to aquatic invertebrates. Stable isotope analyses using delta(13)C and delta(15)N were conducted on blood and feathers of dippers in addition to aquatic invertebrates and salmon fry prey. Linear mixing models using the N-15 isotope in the dippers' diet and blood revealed considerable variability in the proportion of fish consumed (0-71%). Resident dippers on the main river ate significantly higher proportions of fish (42%) than tributary migrants (22%) (P = 0.01). 4. The difference in diet between migratory groups explained some of the observed variation in egg contaminant profiles, as total OC (P = 0.002) in dipper eggs was positively correlated with blood delta(15)N values, indicating fish may be the primary source of contamination. 5. Synthesis and applications. We conclude that dipper eggs represent local conditions at the breeding site, making them useful tools for biomonitoring aquatic contaminants in watersheds. However, given the distinct difference in contaminant profiles between resident and migrant dippers and the link with diet, the results emphasize the importance of understanding individual species' ecology for assessing toxicological effects at the population level.
27. Widmeyer, JR; Crozier, ED; Moore, MM; Jurgensen, A; Bendell-Young, LI. (2004) Role of Leptothrix discophora in mediating metal uptake in the filter-feeding bivalve Mytilus trossulus (edulis).Environmental Science & Technology 38: 769-774 Role of Leptothrix discophora in mediating metal uptake in the filter-feeding bivalve Mytilus trossulus (edulis)
The potential for filter-feeding bivalves to accumulate metals from a wide range of food sources is an important consideration when examining trophic transfer of metals up the food chain. The objective of this study was to determine the role of Leptothrix discophora in mediating metal uptake in the filter-feeding bivalve Mytilus trossulus. The bacterium L. discophora SP-6 was cultured in the absence or presence of Mn, allowing for a naturally formed Mn oxide sheath to develop. Secondary metals (Cd and Pb) were then added to the cultures, allowing for potential Cd and Pb adsorption to the Mn oxide sheath. Resulting bacterial aggregates of known diameter were then fed to the bivalve M. trossulus using a flow-through system. Initial concentrations of both Pb and Cd on the bacterium did not differ significantly in the presence or absence of the Mn oxide; conversely both Pb (F = 7.39, p < 0.0001) and Cd (F = 33.65, P < 0.0001) were found at lower concentrations in the mussel tissue when the Mn oxide was present. To determine whether these differences in metal uptake could be attributed to sorting by the mussel based on food quality, nutritional analysis was performed. Bacterial food matrixes containing Mn oxides were found to have significantly lower levels of carbon (F = 256, p < 0.0001). Particle clearance rates for the various food matrixes were positively correlated with organic content (R-2 = 0.852, p > 0.008). The results of our study suggest that metal uptake in M. trossulus was significantly decreased for Cd with a similar trend for Pb when the SP-6 sheath contained Mn oxides. The mechanism mediating this differential uptake is best explained by food quality, in that a higher quality food source enhanced metal uptake due to an increased clearance rate of organic-rich particles by M. trossulus.
26.Bendell-Young, L. (2003) Peatland interstitialwater chemistry in relation to that of surface pools along a peatland mineral gradient.Water Air and Soil Pollution 143: 363-375 Peatland interstitialwater chemistry in relation to that of surface pools along a peatland mineral gradient
interstitial water; mineral-poor fen; mineral-rich fen; peat chemistry; peatland gradient; silica; surface pool chemistry
The elemental (including silica (Si), calcium (Ca), magnesium (Mg), manganese (Mn) and iron (Fe)) and nutrient composition of peatland surface pools and concentrations of Ca, Mg, Mn, and Fe in peat interstitial waters and surface peat concentrations of oxides of Mn and Fe were determined for 15 peatlands sampled along a mineral gradient. Surface pool concentrations of Si were ca. ten fold less in surface pools of mineral-poor peatlands than in the mineral rich, supporting the use of this element as an indicator of minerotrophic influence in peatlands. Principle component analysis of surface pool water chemistry parameters differentiated mineral-poor and moderately-poor peatlands from mineral-rich peatlands based on the concentrations of Ca, Mg and alkalinity of pools. Several lines of evidence indicated that peatland interstitial waters were important contributors to peatland alkalinity and included; (1) maximum interstitial water concentrations of Ca and Mg correlating with overlying surface pool alkalinity, (2) a negative correlation between interstitial water Ca:Mg ratios and surface pool concentrations of Si and (3) Ca:Mg ratios of moderately-poor to mineral-poor peatland interstitial waters approaching the Ca:Mg ratio of rainwater rather than those of bedrock. Interstitial water concentrations of dissolved Mn and Fe correlated with amounts of reducible Fe and Mn (oxides of Fe and Mn) recovered from the peat/water interface indicating that groundwater inputs are important sources of these two elements to fens. As a consequence, for peatlands that are not truly ombrotrophic, groundwater inputs of Mn and Fe may interfere with interpreting peat metal profiles thought to be due to anthropogenic inputs alone.
25. Barjaktarovic, L; Bendell-Young, LI. (2002) Factors contributing to the salinity of lakes, Riske Creek region, south-central British Columbia, Canada.Applied Geochemistry 17: 605-619 Factors contributing to the salinity of lakes, Riske Creek region, south-central British Columbia, Canada
The objective of this study was to determine the primary factors that contribute to the salinity of lakes located within the Riske Creek region of south-central British Columbia, Canada. The Riske Creek region contains numerous lakes with a salinity range of 0-10.8 ppt with high and low salinity lakes co-existing in close proximity to one another. The region is of extreme ecological importance because it is located on the Pacific flyway and serves as a major breeding ground for a number of waterfowl species. Water budgets, lake water chemistry and cation (Ca2+. Mg2+. Na+ and K+) interstitial water composition were determine for 9 lakes, 3 oligosaline (0 ppt) 3 mesosaline (0.4 1.0 ppt) and 3 euryhaline (2.7-5.3 ppt) to determine if evapo-precipitive or saline groundwater inputs were the primary determinants of lake salinity. Lake water budgets indicated that meso and euryhaline lakes were in a close to zero or negative water balance whereas the 3 oligosaline lakes were in a positive water balance. Groundwater saline inputs, as measured by lake sediment interstitial water cation concentrations. indicated that groundwater made only minor contributions to lake salinity. Water budget calculations and sediment interstitial water chemistry suggest that lakes are saline largely due to evaporative processes. (C) 2002 Elsevier Science Ltd. All rights reserved.
24.Bendell-Young, LI; Thomas, CA; Stecko, JRP. (2002) Contrasting the geochemistry of oxic sediments across ecosystems: a synthesis.Applied Geochemistry 17: 1563-1582 Contrasting the geochemistry of oxic sediments across ecosystems: a synthesis
The geochemistry of oxic sediments was contrasted across a range of Canadian aquatic ecosystems; 7 freshwater lakes, (3 circumneutral and 4 acidic), 15 peatlands (5 mineral-rich, 5 moderately-poor and 5 mineral-poor), 9 wetlands (3 oligosaline, 3 mesosaline and 3 euryhaline), an estuary (deposited and suspended sediments) and an intertidal region. Sediments were characterized by a simultaneous extraction that separated sediments into easily reducible (ER) metal (oxyhydroxides of Mn and easily reducible amorphous oxyhydroxides of Fe) and reducible (R) metal (more crystalline forms of oxyhydroxides of Fe), organic matter, and, the concentrations and partitioning of Zn, Cu and Cd associated with these 3 sediment components. Ecosystems were distinct with respect to ER Fe and organic matter [canonical variate analysis (CVA)] with 53% of among system variation in geochemistry attributed to these 2 components. Sediments of peatlands and wetlands contained greater amounts of organic matter whereas sediments of lakes, intertidal and estuarine deposited and suspended sediments were characterized by greater amounts of ER Fe. A further 21% of among system variation could be ascribed to organically bound Fe that was greater in acidic lakes and mineral-rich peatlands as compared to other systems. Concentration and partitioning of Cd within sediments was regionally dependent with 41% of among system variation (CVA) attributed to differences in ER Cd and R Cd. Cadmium from peatlands and lakes located in Ontario was recovered from all 3 sediment components whereas sediment from wetlands, the estuary and the intertidal regions of British Columbia (BC) contained no organically bound Cd with amounts recovered occurring mostly as ER Cd. Lakes and peatlands located in Ontario contained 3-5-fold total Cd as compared to ecosystems located in BC. A further 21% of among ecosystem variation was attributed to Zn partitioning. Zinc in peatland and wetland sediments occurred as R Zn as compared to lake and estuarine deposited sediments where Zn was recovered both as ER and R Zn. Total Zn was also 3-5-fold greater in sediments of systems in Ontario as compared to those sampled in BC. Concentration and partitioning of Cu was similar across all systems with Cu recovered from the organic component of sediment. The geochemistry of surficial oxic sediments with respect to ER Mn, R Fe and organic matter and the geochemical associations among these sediment components is ecosystem and region dependent. For assessing impacts of metals on sediment dwelling biota the geochemical characteristics of the system under study should first be defined. (C) 2002 Elsevier Science Ltd. All rights reserved.
23. McFarland, CN; Bendell-Young, LI; Guglielmo, C; Williams, TD. (2002) Kidney, liver and bone cadmium content in the western sandpiper in relation to migration.Journal of Environmental Monitoring 4: 791-795 Kidney, liver and bone cadmium content in the western sandpiper in relation to migration
Cadmium content was measured in kidney, liver and tarsus bones of western sandpipers (Calidris mauri) at a temperate migratory stopover site ( Fraser Delta, British Columbia, Canada) and a wintering site ( Playa el Agallito, Chitre, Panama) over a two year period. Cadmium content in liver and kidney was age and sex dependent. Adult females generally had lower kidney and liver cadmium than adult males (P < 0.05), but a sex difference was not detected in juveniles. Cadmium increased with age in kidney, liver and to a lesser extent in bone (P < 0.001) with average "steady-state" kidney and liver content being reached within the sandpipers first year. In general, tissue cadmium residues in adult males and females were independent of sampling location although for bone, site-specific differences did occur (P < 0.001). Bone cadmium was lower in females sampled from their wintering grounds as compared to temperate stopover sites suggesting that bone cadmium may be mobilized during periods of feather molt. Comparison of cadmium residues among sandpipers of increasing age suggest that exposure is occurring along the Pacific Coast, at stopover sites as the birds migrate north to Alaska and south to Panama. This study points to the importance of considering the ecology of the species (e.g., in this case migratory behavior) in interpreting trace metal residues.
22. O'Keeffe, J; Bendell-Young, LI. (2002) Uptake of cadmium by the invasive perennial weeds Ranunculus repens and Geranium robertianum under laboratory conditions.Journal of Environmental Monitoring 4: 413-416 Uptake of cadmium by the invasive perennial weeds <i>Ranunculus repens</i> and <i>Geranium robertianum</i> under laboratory conditions
The objective of this study was to compare the accumulation and partitioning-of cadmium (Cd) in a fibrous versus a tap root weed, Ranunculus repens and Geranium robertianum respectively. To meet this objective, we compared the accumulation by and the partitioning of Cd in R. repens versus G. robertianum grown in soils spiked with 0.015 grams of Cd for a period of three weeks. The rate of Cd uptake was also compared by following the fate of Cd-109 within the root, stem and leaf of the two weeds. Prior to Cd exposure, leaf and stem of control R. repens contained significantly greater amounts of Cd as compared to G. robertianum, whereas Cd concentrations in roots of the control plants for the two species were not significantly different (p > 0.05, student's t-test). Post Cd exposure the two species contained similar amounts of, Cd in leaf and stem, however, roots of R. repens contained almost two-fold the amounts of Cd as compared to G. robertianum. Comparison of k (h(-1), rate of Cd-109 uptake) for stem, leaf and root of the two species indicated that G. robertianum accumulated Cd-109 over the first 24-48 h at a faster rate as compared to R. repens. For both species and all three organs, maximum accumulation of Cd-109 occurred within the first 24-48 h. Our findings indicate that the fate of Cd within these two species is quite different with the fibrous root of R. repens serving to accumulate and store Cd whereas in G. robertianum, Cd is rapidly taken up and tends to be accumulated within its leaf.
21. Arifin, Z; Bendell-Young, LI. (2001) Cost of selective feeding by the blue mussel (Mytilus trossulus) as measured by respiration and ammonia excretion rates.Journal of Experimental Marine Biology and Ecology 260: 259-269 Cost of selective feeding by the blue mussel (Mytilus trossulus) as measured by respiration and ammonia excretion rates
cost of selective feeding; respiration; ammonia excretion
The metabolic cost as measured by respiration and ammonia excretion rates associated with a selective as compared to a non-selective feeding behaviour was determined for the blue mussel, Mytilus trossulus. Mussels were challenged with four environmentally relevant seston matrices of different quality and quantity, which were known to evoke either a sorting response (i.e., selective feeding) where organic-rich particles were selected over inorganic particles as compared to no sorting (i.e., non-selective) where either inorganic or organic particles were ingested by the bivalve. Seston matrices were prepared by mixing known quantities of silt and algae such that the following extent of feeding responses would occur; no pre-sorting of ingested material, (1) no algae + 50 mg silt l(-1), (2) 150 X 10(6) cells l(-1) of algae + no silt, and, where pre-sorting of ingested material occurred, (3) 20 X 10(6) cells l(-1) of algae and 20 mg l(-1) of silt, and (4) 150 X 10(6) cells l(-1) of algae and 50 mg l(1) of silt. A control, which represented basal metabolism consisting of mussels exposed only to filtered seawater (0.45 mum), was included for a total of five treatments. Mussel respiration and ammonia excretion rates were independent of whether mussels were pre-sorting or not sorting ingested material. Of the four matrices, only rates determined for conditions of maximum seston quality and quantity where pre-sorting of the seston occurred were significantly different from control mussels (p < 0.05, ANOVA). Estimates of net energy used for feeding, where net energy is total energy intake (food) minus energy expenditure (energy lost through respiration and excreta as measured by ammonia excretion rates), indicated that feeding, whether selective or non-selective required only 0.92% of net energy intake. Hence, mussels appear to be highly adapted to a dynamic food environment with negligible costs associated with the feeding process, even when significant pre-selection of organic-rich particles occurs. (C) 2001 Elsevier Science B.V. AII rights reserved.
20. Barjaktarovic, L; Bendell-Young, LI. (2001) Accumulation of Cd-109 by second-generation chironominae propagated from wild populations sampled from low-, mid-, and high-saline environments.Archives of Environmental Contamination and Toxicology 40: 339-344 Accumulation of Cd-109 by second-generation chironominae propagated from wild populations sampled from low-, mid-, and high-saline environments
Our objective was to determine if second-generation (F2) chironomids propagated from adults of larvae sampled from low-, mid-, and high-saline environments differed in their ability to accumulate cadmium from their environment. Second-generation chironomids cultured from wild populations were exposed to Cd-109 at 0, 0.7, and 4.3 ppt salinity for 10 days, at which time survival and amounts of Cd-109 accumulated were determined. Cultures included two of Chironomus tentans from a freshwater lake (lake 78; 0 ppt), and the euryhaline C. athalassicus from a mid- (lake 71; 0.7 ppt) and high (lake 56; 4.3 ppt)-saline environment. A laboratory-reared culture of C. tentans was included as a positive control. Species-dependent accumulation of Cd-109 occurred; second-generation C. athalassicus cultured from the high-salinity lake survived in the three salinities and accumulated significantly greater amounts of the radiotracer at 0 and 0.7 ppt compared to the second-generation freshwater species, C. tentans. Second-generation C. athalassicus cultured from lake 71 also survived all salinities with Cd-109 accumulation tending to be greater than the freshwater species at the mid-salinity range. In contrast, the freshwater species cultured from lake 78 as well as the laboratory-reared culture did not survive the highest salinity of 4.3 ppt and accumulated less Cd-109 compared to the species from the high-saline environments. Species-dependent differences in metal accumulation need to be considered in studies that assess metal concentrations in aquatic organisms across an environmental gradient, such as salinity.
19. Crowe, AU; Han, B; Kermode, AR; Bendell-Young, LI; Plant, AL. (2001) Effects of oil sands effluent on cattail and clover: photosynthesis and the level of stress proteins.Environmental Pollution 113: 311-322 Effects of oil sands effluent on cattail and clover: photosynthesis and the level of stress proteins
cattail; Typha latifolia L.; clover; Trifolium hybridum L.; apparent photosynthesis; RuBisCo; osmotic stress
The oil sands industry located in northeastern Alberta, Canada, generates large volumes of effluent characterized by a high level of dissolved ions and naphthenic acids. The dikes used to store the effluent seep, creating wetlands which are subsequently invaded by obligate wetland flora such as cattail (Typha latifolia L.). The appearance of these wetlands prompted the oil sands industry to consider wetlands as part of their reclamation strategy. However, to ensure long-term viability of such wetlands, the response of the flora to the industrial effluent needed to be determined. To this end, apparent photosynthesis (APS), the level of ribulose-1,5-bisphosphate carboxylase (RuBisCo) large subunit, dehydrin-related polypeptides, and protein disulphide isomerase (PDI) were evaluated in cattail and alsike clover plants (Trifolium hybridum L.) exposed to the oil sands effluent. APS measured in plants impacted by oil sands effluent was significantly higher than that of plants in the non-impacted off-site location. Among the on-site locations, plants growing in the natural wetlands site had higher APS compared to all other sites. The level of RuBisCo was not increased in cattail or clover growing in effluent-contaminated sites indicating that enhanced photosynthesis was not due to greater levels of this enzyme. Dehydrin-related polypeptides were detected only in the roots of cattail and were absent in clover. The polypeptide profile was altered in cattail exposed to oil sands effluent indicating that they were responding to an osmotic stress. The level of PDI was unaffected in the leaves of cattail regardless of the nature of the effluent to which they were exposed. Overall, the data indicate that cattail and clover are adapted to the oil sands effluent, although further studies are needed to assess their longterm ability to survive in the presence of this anthropogenic stress. (C) 2001 Elsevier Science Ltd. All rights reserved.
18. Kambey, JL; Farrell, AP; Bendell-Young, LI. (2001) Influence of illegal gold mining on mercury levels in fish of North Sulawesi's Minahasa Peninsula, (Indonesia).Environmental Pollution 114: 299-302 Influence of illegal gold mining on mercury levels in fish of North Sulawesi's Minahasa Peninsula, (Indonesia)
mercury; illegal mines; human health; fish consumption
North Sulawesi's Minahasa Peninsula currently is experiencing intense illegal gold mining activity. It has been estimated that 200 t of mercury are used annually in Indonesia in the recovery of gold from the illegal mines. To date no study has assessed the environmental impact of this illegal activity on the nearby aquatic biota. To address this concern, we compared tissue mercury levels from several sites, including a reference site and a site near an illegal mine. Fish from the region of the illegal mine contained 30 times the mercury content of fish at the reference site. Moreover, whole fish tissue levels were four times those recommended by the World Health Organization for consumption restrictions and often two-fold higher than recommended for total restriction on fish consumption. The environmental and human health implications of these levels are of grave concern; citizen education programmes are required to alert indigenous peoples of the risks associated with mercury exposure and fish consumption guidelines put into place. A more comprehensive effort to identify major sources and effects are required. Such information can be used to determine the correct course of action that needs to be taken to close existing illegal mines and prevent future illegal mining activities. (C) 2001 Elsevier Science Ltd. All rights reserved.
17. Norton, ML; Bendell, JF; Bendell-Young, LI; LeBlanc, CW. (2001) Secondary effects of the pesticide Bacillus thuringiensis kurstaki on chicks of spruce grouse (Dendragapus canadensis).Archives of Environmental Contamination and Toxicology 41: 369-373 Secondary effects of the pesticide Bacillus thuringiensis kurstaki on chicks of spruce grouse (Dendragapus canadensis)
The objective of this study was to determine if application of the biological pesticide Bacillus thuringiensis kurstaki (B.t.k.) had secondary effects on spruce grouse (Dendragaptis canadensis) chicks in the southern boreal forest of Ontario, Canada. B.t.k. kills larvae of Lepidoptera that ir-light otherwise be food. This may affect types of food ingested and influence chick growth rates by reducing the availability of a high-protein food. Amount of ingested grit, which is diet-dependent, may also be influenced, which could alter exposure to anthropogenic toxic metals, such as cadmium (Cd) and lead (Pb), associated with the grit. Chick growth rate from 0 to 14 days of age was determined, and gizzard contents were analyzed for types of foods and levels of macronutrients and trace metals in chicks raised in a plot treated with B.t.k. compared to chicks raised on a control plot. Chick growth rates were significantly different (p < 0.05); chicks from the treatment plot increased body mass 30% less as compared to chicks raised on the control plot. Control chicks contained on average 2.5-fold the mass (in g) of grit and nearly twofold the mass of food, which included larvae, in their gizzards compared to those exposed to B.t.k. whose diets were dominated by spiders and ants. Concentrations of magnesium (Mg), calcium (Ca), phosphorous (P), iron (Fe), manganese (Mn), sulfur (S) and the trace metals zinc (Zn), copper (Cu), nickel (Ni), and chromium (Cr) did not differ between experimental and control birds (p > 0.05). In contrast, control chicks had higher levels of aluminum (Al), Cd, cobalt (Co), and Pb in their gizzards than chicks from the sprayed area (p < 0.05), attributed to greater amounts of consumed grit. Although birds from the sprayed area had lower levels of the toxic metals Pb and Cd in their gizzards, a protein-deficient diet could have been a factor that contributed to decreased rates of growth in B.t.k.-exposed birds as compared to those birds held on nonsprayed sites. Reduced growth during the first 2 weeks of avian development has important consequences at the population level, and it is recommended that this secondary effect be considered for all species who rely on Lepidoptera larvae as a food resource prior to wide spread application of B.t.k. for insect control.
16. Arifin, Z; Bendell-Young, LI. (2000) Influence of a selective feeding behaviour by the blue mussel Mytilus trossulus on the assimilation of Cd-109 from environmentally relevant seston matrices.Marine Ecology-Progress Series 192: 181-193 Influence of a selective feeding behaviour by the blue mussel Mytilus trossulus on the assimilation of Cd-109 from environmentally relevant seston matrices
Mytilus trossulus; Cd-109-AE; inorganic seston; organic seston
The objective of this study was to determine the influence of a selective feeding strategy on the assimilation efficiency of Cd-109 (Cd-109-AE) by the blue mussel Mytilus trossulus. Two complementary experiments which used 5 seston matrices of different seston quality (SQ) were implemented: (1) algae labeled with Cd-109 was mixed with unlabeled silt, and (2) labeled silt was mixed with unlabeled algae. Cd-109-AE was determined by a dual-tracer ratio (Cd-109/Am-241) method (DTR) and based on the ingestion rate of Cd-109 by the mussel (IRM) (total amount of Cd-109 ingested over the 4 h feeding period). As a result of the non-conservative behavior of Am-241, the DTR underestimated mussel Cd-109-AEs as compared to the IRM. Therefore only IRM-determined Cd-109-AE was considered further. When only algae was spiked, Cd-109-AEs were proportional to diet quality (DQ), (r = 0.98; p < 0.05) with maximum Cd-109-AE occurring at the mussel's filter-feeding 'optimum' and where maximum carbon assimilation rates have been observed. However, for the spiked-silt exposures, Cd-109-AE was independent of DQ, with maximum values of similar to 85% occurring in all diets except for silt alone. Cd-109-AE for the silt-only exposure was 36%, suggesting that digestive processes which occur in diets of both algae and silt were not operating as effectively in the silt-only exposures. Cd-109-AE correlated with Cd-109 in mussel tissue (r = 0.63; p < 0.05), with the radiotracer assimilated from the silt-labeled matrices corresponding to the greatest amounts of Cd-109 activity within the mussel. These results suggest an active and passive assimilation of Cd-109 from the algae and silt components of seston respectively. Active Cd-109-AE will be proportional to DQ with maximum assimilation possibly occurring at the mussel's filter-feeding optimum. Passive Cd-109-AE will be dependent on amounts of metal associated with the inorganic component of seston, with digestive processes that are activated in the presence of algae concurrently desorbing inorganic cadmium. Although both components of the diet will be important for determining amounts of Cd that can be potentially assimilated from seston by filter-feeding organisms, the contribution from the inorganic component of seston will Likely overwhelm that from the organic fraction. Therefore, predictive models of metal accumulation by seston-ingesting organisms need to consider the role of both seston components in contributing to amounts of metal ultimately assimilated by the organism.
15.Bendell-Young, LI; Bennett, KE; Crowe, A; Kennedy, CJ; Kermode, AR; Moore, MM; Plant, AL; Wood, A. (2000) Ecological characteristics of wetlands receiving an industrial effluent.Ecological Applications 10: 310-322 Ecological characteristics of wetlands receiving an industrial effluent
anthropogenic impacts; benthic community structure; ecosystem characteristics; fish acute lethality and stress; oil sands; wetlands
The primary objectives of this study were to evaluate the ecological characteristics of wetland ecosystems that had developed in response to oil sands effluent relative to reference wetland ecosystems and, from such an evaluation, to assess whether these wetlands were viable systems capable of integrating into the northern Canadian landscape. A secondary objective was to evaluate the use of several ecologically relevant endpoints as indicators of an ecosystem response to a known anthropogenic stress, in this case, wetlands receiving oil sands effluent. To achieve this, a suite of endpoints were compared between effluent-impacted wetlands and nonimpacted reference wetlands. Endpoints for comparison included: (1) benthic macroinvertebrate community structure, (2) chironomid density and biomass, (3) the incidence of chironomid mentum deformities, (4) the mutagenetic potential of sediment-dwelling chironomids, (5) growth and photosynthetic rare for the aquatic plant Typha latifolia (cattail), and (6) fish acute lethality and stress response as measured by changes in blood chemistry (percentage hematocrit [%hct], percentage leucocrit [%lct], and differential white blood cell count). Wetlands receiving oil sands effluent supported a low-diversity benthic community, dominated primarily by the Chironomidae and cattail. There was no evidence of mentum deformities or mutagenicity in chironomids sampled from the oil-impacted wetlands. Cattails grown in oil sands effluent and sediment demonstrated increased photosynthetic rates; however, these increased rates did not translate into increased plant growth. In contrast to the benthic community and the cattail, indigenous fish were unable to survive in wetlands containing oil sands effluent. Fish displayed altered blood chemistry (elevated %hct, depressed %lct) and ultimately death when held beyond 14 d in the oil-impacted wetlands. Of the various ecological endpoints measured, the macroinvertebrate community and changes in fish blood chemistry were the most sensitive indicators of an anthropogenic stress, demonstrating distinct differences in response between impacted and reference wetlands. To ensure that these wetlands can safely integrate into the northern Canadian landscape, future studies need to focus on their impacts at higher trophic levels indigenous to the wetland.
14. King, JR; Bendell-Young, LI. (2000) Toxicological significance of grit replacement times for juvenile mallards.Journal of Wildlife Management 64: 858-862 Toxicological significance of grit replacement times for juvenile mallards
Anas platyrhynchos; gizzard; grit ingestion; juveniles; mallard; oil and grease; turnover time; waterfowl
Grit ingestion may be an important exposure route for environmental contaminants in waterfowl. Our objective was to determine turnover rate of grit in juvenile mallards (Anas platyrhynchos) by measuring the time required for juveniles to totally replace grit in the gizzard. To demonstrate the relevance of turnover rate for assessing contaminant exposure, we evaluated the suitability of wetlands receiving oil-sand effluent generated by the mining industry, as viable habitat for waterfowl. Captive mallards were allowed free access to pools of colored grit, the grit color was changed and the time required for color 1 to be replaced by color 2 determined. hn exponential relationship between percent grit turnover and time was fitted to the data to obtain a grit turnover rate, k = 0.02/hr. This rate was used to determine amount of contaminants that would be ingested over 21 days by juvenile mallards using oil-sand wetlands as habital. We demonstrate that grit ingestion could be a significant route of contaminant exposure, specifically for oil-sand related compounds such as oil and grease and naphthenic acids, to waterfowl.
13. Pollet, I; Bendell-Young, LI. (2000) Amphibians as indicators of wetland quality in wetlands forme from oil sands effluent.Environmental Toxicology and Chemistry 19: 2589-2597 Amphibians as indicators of wetland quality in wetlands forme from oil sands effluent
anuran; amphibians; created oil sands-based wetlands; toxicity; tadpoles
Fort McMurray, Alberta, Canada, is home to the largest oil sands mining operation in the world. Two of the companies currently mining; the oil sands hope to use wetlands formed from oil sands effluent as part of their reclamation strategy required at mine closure. To evaluate the ability of these created wetlands to sustain amphibians, one population of Bufo boreas tadpoles and three different populations of Rana sylvatica tadpoles were exposed to oil sands process-affected water representative of a range of effluents expected to occur on the oil sands lease site at mine closure. Endpoints used to assess the response of the tadpoles to the process-affected waters included survival, growth, rate of development, and frequency of physical deformities. Bufo boreas held in process-affected waters displayed significantly reduced growth and prolonged developmental time (days to metamorphosis) as compared to those held in reference waters. The response of the three separate populations of R. sylvatica were population dependent. Two of the three populations responded similarly, demonstrating decreased survival and significantly reduced;rates of growth when held in process-affected waters as compared to reference waters; the third was highly sensitive, displaying no growth and extremely poor survival in all exposures, suggesting different tolerances to the process-affected waters among different R. sylvatica tadpole populations. Amphibians such as B. boreas and R. sylvatica were sensitive indicators of effluent quality. Based on the effluents used in this study, wetlands formed from oil sands effluent will not support viable amphibian populations.
12. Stecko, JRP; Bendell-Young, LI. (2000) Contrasting the geochemistry of suspended particulate matter and deposited sediments within an estuary.Applied Geochemistry 15: 753-775 Contrasting the geochemistry of suspended particulate matter and deposited sediments within an estuary
The geochemistry, as defined by amounts of easily reducible Mn (ERMn; Mn oxides), reducible Fe (RFe; Fe oxides), organic matter (% loss on ignition), total metal (Cu, Pb and Zn) and metals associated with the ERMn, RFe and organic matter components of deposited sediments (DS) and suspended particulate matter (SPM) were contrasted over a 1-year period (two-way ANOVA with sediment type and month as the two factors) within the Fraser River Estuary, BC, Canada. The geochemistry of SPM as compared to DS was distinctly different. The geochemistry of SPM displayed a marked seasonality. By contrast, seasonal differences in the geochemistry of DS were much less pronounced over the 12-month sampling period. Concentrations of organic matter and RFe in SPM were significantly greater (two-way ANOVA; P < 0.05) in winter months maximums of 23% and 53 g kg(-1) respectively) as compared to the rest of the year (maximums of 9.3% and 11 g kg(-1), respectively). Concentrations of organic matter in DS did not change over the 12-month period; however, RFe in DS was significantly greater in winter months (7.3 g kg(-1)) as compared to summer months (2.3 g kg(-1)). Easily reducible Mn in both SPM: and DS was highly variable throughout the year with no apparent seasonal dependence. Total concentrations of Cu, Pb and Zn and their partitioning among the 3 sediment components (i.e. ERMn, RFe and organic matter) were also month-dependent (two-way ANOVA, P < 0.05); metal concentrations in SPM were up to 17 times greater than DS with a higher proportion of these metals associated with the easily reducible component (oxides of Mn and amorphous forms of Fe oxides) during winter as compared to summer months. Trace metal concentrations and partitioning in DS showed the same seasonal trends, although not to the same degree as occurred for SPM, throughout the 4 seasons of study. Seasonal changes in the partitioning of metals in addition to greater proportions of the metal occurring in an easily reducible form in SPM relative to DS has potentially important implications for sediment ingesting organisms capable of filter-feeding on both SPM and DS. Specifically, metal bioavailability to sediment ingesting organisms from SPM may be seasonally dependent with periods of greatest exposure occurring during winter months, as compared to DS where no seasonal dependence occurs. To identify main vectors of metal exposure to sediment ingesting organisms, both the type off sediment and when they are feeding on the particular type of sediment need to be determined. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.
11. Stecko, JRP; Bendell-Young, LI. (2000) Uptake of Cd-109 from sediments by the bivalves Macoma balthica and Protothaca staminea.Aquatic Toxicology 47: 147-159 Uptake of Cd-109 from sediments by the bivalves Macoma balthica and Protothaca staminea
sediment geochemistry; bivalve; filter-feeding behaviour; metal uptake
This study (1) compared the relative importance of suspended particulate matter (SPM) and deposited sediment (DS) as a source of cadmium exposure to two sediment ingesting bivalves, and (2) determined the importance of feeding behaviour on cadmium uptake from SPM and DS by comparing metal uptake from ingested sediments by a facultative and an obligate filter-feeder. Two types of sediment, deposited (DS) and suspended (SPM) sediments were sampled from the Fraser River Estuary and geochemically characterized with respect to amounts of easily reducible manganese and reducible iron (manganese and iron oxides respectively), organic matter, and amounts of cadmium associated with each of the three components. Sediments were radiolabeled with Cd-109, with the labelled sediments then fed to Macoma balthica and Protothaca staminea, a facultative filter-feeder and an obligate filter-feeder respectively. Amounts of radiotracer accumulated by the bivalves from the two types of sediment over an 8-day period were then assessed. The geochemistry of DS was distinct from that of SPM with DS containing almost half the concentrations of oxides of manganese and iron as compared to SPM. Natural cadmium was recovered primarily from the easily reducible (associated with oxides of manganese) followed by the reducible (associated with oxides of iron) sediment component, for both SPM and DS. In contrast, Cd-109 was recovered from the reducible fraction: followed by the easily reducible fraction from the two types of sediment. No natural cadmium or Cd-109 was recovered from the organic component of either sediment. For both bivalves, uptake of Cd-109 from sediment as compared to water accounted for ca. 80% of accumulated radiotracer. Uptake of Cd-109 from DS was significantly greater than from SPM, most notably for P. staminea. For M. balthica, the amount of accumulated Cd-109 was best explained by the degree of isotope desorption from DS. In contrast, Cd-109 accumulation by P. staminea was best described by its feeding behaviour. Metal accumulation by sediment-ingesting organisms is not simply related to sediment metal concentrations but will also depend on the strength of association of the metal within the sediment (for facultative feeders), and the feeding behaviour of the bivalve. Cd-109 partitioning in DS and SPM did not parallel the field partitioning of cadmium which precluded our objective of assessing the relative importance of SPM and DS as a source of cadmium to facultative filter-feeders. To elucidate the role of complex sediment geochemistry in influencing metal availability to sediment ingesting organisms, further study is needed on ways to either label or spike natural complex sediments such that the speciation achieved under laboratory conditions is that which is observed in the field. (C) 2000 Elsevier Science B.V. All rights reserved.
10.Bendell-Young, L. (1999) Contrasting the sorption of Zn by oxyhydroxides of Mn and Fe, and organic matter along a mineral-poor to mineral-rich fen gradient.Applied Geochemistry 14: 719-734 Contrasting the sorption of Zn by oxyhydroxides of Mn and Fe, and organic matter along a mineral-poor to mineral-rich fen gradient
The geochemistry of Mn and Fe in surface pools, pore-waters and surface peats and the sorption of Zn by the surface peats was contrasted among 15 peatlands sampled along a mineral-poor to mineral-rich fen gradient. Sorption of Zn by surficial peats was compared via distribution coefficients, both total (K-DT) and partial (K-DERMn, K-DRFe and K-DORG), where ER Mn, R Fe and ORG are amounts of Zn recovered from the easily reducible Mn oxides, reducible Fe oxides, and organic components of peat, respectively. Apparent stability constants (K(A)s) for Zn sorption onto oxides of Fe recovered from the surface peats were also calculated and compared along the same gradient. Feat geochemistry was peatland dependent; mineral-poor fens had less easily reducible Mn and greater amounts of organic matter (%Loss on Ignition; LOI) versus mineral-rich fens (range of 0.66-8.6 mm kg(-1) for ER Mn and 20-88% LOI for organic matter), Reducible Fe also varied among peatlands (range 51-315 mm kg(-1)) but was independent of the mineral-poor to mineral-rich fen gradient. Comparison of partial K(D)s for amounts of Zn sorped onto the ER Mn, R Fe and ORG components of peat indicated that sorption was dominated by R Fe in all peatlands. KD-rs ranged from 0.54-2.00, In contrast to other aquatic systems, however, the range in K(DT)s was not related to either surface or pore-water pH. KAs ranged from 0.35 to 3.06 and were also independent of surface or pore-water pH. However, average K(A)s (but not K(DT)s), were greater for mineral-poor fens (P < 0.02), suggesting greater Zn binding by surface peats of mineral-poor fens versus either the moderately poor or mineral-rich peatlands. Other water chemistry variables, such as pore-water base cation concentrations, weakly correlated to Zn partitioning onto R Fe (r = -0.35, P = 0.05), but did not fully explain differences in Zn partitioning among peatlands. Greater average KAs for the mineral-poor peatlands may in part be due to the presence of strong metalorganic matter-Fe oxide complexes in the Sphagnum dominated peatlands as well as lower pore-water base cation concentrations that occur in the mineral-poor peatland as compared to the more mineral-rich fens. (C) 1999 Elsevier Science Ltd. All rights reserved.
9.Bendell-Young, LI. (1999) Application of a kinetic model of bioaccumulation across a pH and salinity gradient for the prediction of cadmium uptake by the sediment dwelling chironomidae.Environmental Science & Technology 33: 1501-1508 Application of a kinetic model of bioaccumulation across a pH and salinity gradient for the prediction of cadmium uptake by the sediment dwelling chironomidae
A kinetic model for the prediction of metal concentrations in aquatic organisms was applied for the prediction of cadmium concentrations in the sediment dwelling dipertan larvae, Chironomidae. Cadmium concentrations were determined in Chironomidae sampled along two distinct environmental gradients: (1) an acidity gradient(from pH 5.0-6.5) and (2) a salinity gradient (from 0 to 9.6 ppt). Comparison of predicted and observed values indicated that the kinetic model was successful in predicting concentrations in chironomids sampled along the acidity gradient but not the salinity gradient. Separation of routes of cadmium uptake into food and solute sources indicated that ingested sediment accounted for 60-100% of total invertebrate cadmium concentrations, however, the relative importance of water increased as a function of decreasing acidity and salinity. These results support the refinement of a kinetic model for predicting cadmium concentrations in sediment-living invertebrates, such as Chironomidae. By allowing for uptake from food and water the model highlighted the potential for routes of cadmium uptake to be pH and salinity dependent. For monitoring purposes, hath vectors and the potential for the relative importance for each vector to change needs to be considered when assessing the degree of metal exposure to sediment ingesting invertebrates which inhabit systems with either a natural or anthropogencially induced gradient in key water chemistry variables such as salinity or pH.
8.Bendell-Young, LI; Bendell, JF. (1999) Grit ingestion as a source of metal exposure in the spruce grouse, Dendragapus canadensis.Environmental Pollution 106: 405-412 Grit ingestion as a source of metal exposure in the spruce grouse, Dendragapus canadensis
grit ingestion; crop; gizzard; metals; grouse
The objective of this study was to determine if ingestion of grit was a source of metal exposure to the spruce grouse, Dendragapus canadensis. A secondary objective was to assess whether grit could provide a supplemental source of essential minerals to their diet. Ca, P, Mg, S, Zn, Cu, Ni, Co, Cr, Fe, Mn, Al, Pb and Cd of liver (adult, yearling, chicks), crop and gizzard contents (adults) were determined for grouse collected from a relatively pristine boreal forest region of north-central Ontario, Canada. With the exception of Cd liver, concentrations were independent of age [one-way analysis of variance (ANOVA); p > 0.004). Zn liver concentrations tended to be greater in adults than yearlings and chicks tone-way ANOVA; p = 0.02). Liver concentrations of Cd increased with age (r = 0.99; p < 0.001). The contribution of crop items to total gizzard elemental content was element specific; crop contents contributed 90-100% of Mn and Zn, 70% for P and Ca, 60% for Pb, 50% for S, and 0-25% for Cu, Mg, Ni, Al, Fe, Co, Cr and Cd to the total elemental concentration of gizzard contents (crop plus grit). Incorporation of grit by grouse could, therefore, constitute an important source of essential macro-(Ca, P, Mg, S) and trace elements (Cu, Fe) but not for Mn or Zn. However, in addition to providing nutrients to the bird, ingestion of grit results in exposure to toxic trace metals such as Cd which in turn is accumulating in the liver. Research directed at determining grit turnover time, and hence metal exposure rates, in bird species which ingest grit to aid in food digestion is required. The toxicological significance of Cd exposure to grit-ingesting birds needs attention. (C) 1999 Elsevier Science Ltd. All rights reserved.
7. Pollet, I; Bendell-Young, LI. (1999) Uptake of Cd-109 from natural sediments by the blue mussel Mytilus trossulus in relation to sediment nutritional and geochemical composition.Archives of Environmental Contamination and Toxicology 36: 288-294 Uptake of Cd-109 from natural sediments by the blue mussel Mytilus trossulus in relation to sediment nutritional and geochemical composition
The objective of this study was to determine if trace metal bioavailability from suspended particulate matter (SPM) and recently deposited lake sediment (LS) to the filter-feeding bivalve Mytilus trossulus was dependent on the nutritional content and/or the geochemistry of the sediment. For SPM these characteristics are seasonally dependent; for LS they are dependent on lake chemistry and trophic status. To meet this objective, SPM was sampled from the Fraser River estuary, British Columbia, Canada, during Winter (March), spring (April, May), and summer (June, July) months. Deposited LS was sampled from an acidic dystrophic and a circumneutral, oligotrophic lake. Sediments were labeled with Cd-109, fed to M. trossulus and the amount of Cd-109 accumulated over a 4-h feeding period assessed. Simultaneous extraction (separation of the sediment into easily reducible, reducible, and organic sediment components) of the radiolabeled sediments indicated that Cd-109 associated with the inorganic, not the organic portion of sediment. The amount of Cd-109 accumulated by the mussel over the 4-h feeding period was dependent on sediment %carbon (%C) and %nitrogen (%N) content (R-2 = 0.75 and 0.52, respectively for SPM and R-2 = 0.76 and 0.64 for LS, respectively), and not on sediment concentrations of easily reducible manganese or reducible iron. These findings suggest that mussels obtain Cd-109 from the inorganic portion of sediment as a consequence of,digestive processes that are selecting for the carbon and nitrogen component of sediment. Hence, accumulation of cadmium from sediment will be dependent on sediment %C, and to a lesser extent %N content; however, amounts that the organism will be exposed to will depend on concentrations present on the inorganic component. Predictive models of metal accumulation by filter-feeding organisms need to consider the role of both sediment components for predicting amounts of metal that the organisms will bioaccumulate.
6. Thomas, CA; Bendell-Young, LI. (1999) The significance of diagenesis versus riverine input in contributing to the sediment geochemical matrix of iron and manganese in an intertidal region.Estuarine Coastal and Shelf Science 48: 635-647 The significance of diagenesis versus riverine input in contributing to the sediment geochemical matrix of iron and manganese in an intertidal region
iron oxides; manganese oxides; diagenesis; sediment geochemistry; Canada west coast
Summer porewater and spring and summer surficial sediment samples were collected from 26 locations in the intertidal region of the Eraser River estuary. Porewaters were analysed for dissolved iron and manganese las defined by species <0.2 mu m in diameter) to assess the contribution of diagenesis to concentrations of iron and manganese oxides at the sediment-water interface. Surficial sediment samples were geochemically characterized as: % organic matter (% LOI); reducible iron (RED Fe, iron oxides) and easily reducible manganese (ER Mn, manganese oxides). Grain size at each site was also determined. The sediment geochemical matrix, as defined by the above four parameters, was highly heterogeneous throughout the intertidal region (three-way ANOVA; P<0.0001). For RED Fe and ER Mn, this heterogeneity could be explained by either diagenetic processes (RED Fe) or by a combination of the proximity of the sample sites to the mouth of the Eraser River estuary plus diagenetic processes (ER Mn). Correlation (Spearman Rank Correlation Test (r(s)), of dissolved iron within the subsurface sediments with amounts of RED Fe recovered from the associated surface sediments was highly significant (r(s)=0.80, P<0.0001); high concentrations of RED Fe at the sediment-water interface co-occurred with high concentrations of dissolved iron, regardless of the proximity of the sample locations to riverine input. Compared with iron, the relationship between dissolved manganese and ER Mn from surface sediments was lower (r(s)=0.58; P<0.0008). Locations most strongly influenced by the Fraser River contained greater concentrations of ER Mn at the sediment-water interface than that which would be expected based on the contribution from diagenesis alone. Sediment grain size and organic matter were also influenced by the proximity ro riverine input. Surficial sediment of sites close to the river mouth were comprised primarily of percent silt (2.0 mu m-50 mu m) whereas sites not influenced by riverine input were primarily percent sand (grain size >50 mu m). Concentrations of organic matter declined from the mouth to the foreslope of the estuary. With the exception of RED Fe, temporal variation (May vs July) was insignificant (P>0.05, three-way ANOVA). Concentrations of RED Fe recovered from the surficial sediments were in general greater in the summer vs spring months, although spring and summer values were highly correlated (Pearson Product Moment Correlation Coefficient; PPCC; r=0.89; P<0.0001). As the bioavailability of metals is dependent on sediment geochemistry, availability throughout the intertidal region will also be spatially dependent. This heterogeneity needs to be taken into account in studies addressing the impact of metals on estuarine systems. (C) 1999 Academic Press.
5. Thomas, CA; Bendell-Young, LI. (1998) Linking the sediment geochemistry of an intertidal region to metal bioavailability in the deposit feeder Macoma balthica.Marine Ecology-Progress Series 173: 197-213 Linking the sediment geochemistry of an intertidal region to metal bioavailability in the deposit feeder Macoma balthica
sediment geochemistry; metal bioavailability; Macoma balthica
Surficial sediment and biota samples were collected from 26 locations in the intertidal region of the Eraser River estuary (British Columbia, Canada). Sediment samples were collected in May and July of 1995. Benthic samples of Macoma balthica, a deposit feeding bivalve, were collected from each site in July. Sediments were characterized by a simultaneous extraction procedure that characterized the sediment matrix into oxides of manganese and iron (easily reducible Mn, ER Mn, and reducible Fe, RED Fe) and organic matter and separated the trace metals, cadmium, copper, lead, nickel and zinc among these 3 'biologically relevant' sediment components, i.e. metals associated with ER Mn, RED Fe and organic matter. Total mercury was also determined in each sediment sample. Bivalve samples were separated into shell and tissue and analysed for the same metals. An R-2 MAX procedure was applied to determine if the concentration of trace metals in the shell and tissue of M. balthica was related to sediment geochemistry using sediment geochemistry and bivalve metal concentrations as the independent variable and dependent variable respectively. The partitioning of trace metals was dependent on the location-specific geochemistry (i.e. amounts of ER Mn, RED Fe and organic matter recovered at each location). This in turn led to differences in metal uptake by M. balthica that were related to sediment geochemistry. The relationships with tissues were highly significant (p less than or equal to 0.001), except for mercury (p less than or equal to 0.05). Sediment geochemistry accounted for 31% of the variability for cadmium, 39% for zinc, 51% for copper and 54% for lead. Relationships were not as strong for shells; sediment geochemistry explained 12 % of the variation for mercury, 15 % for zinc, 21 % for nickel and 43 % for copper. Overall, metal levels in the tissue and shell of M. balthica were best related to the concentration of metal associated with the ER Mn component of sediment. The sediment geochemical matrix as defined by ER Mn, RED Fe and organic matter and the partitioning of trace metals among the 3 fractions was highly site-specific. This in turn led to site-specific patterns in metal bioavailability to M, balthica. The spatial heterogeneity that occurs within an estuary, on the scale of metres, must be considered when assessing the impact of metals on such regions.
4. Arifin, Z; Bendell-Young, LI. (1997) Feeding response and carbon assimilation by the blue mussel Mytilus trossulus exposed to environmentally relevant seston matrices.Marine Ecology-Progress Series 160: 241-253 Feeding response and carbon assimilation by the blue mussel Mytilus trossulus exposed to environmentally relevant seston matrices
Mytilus trossulus; feeding behaviour; sorting process; pseudofaeces; ingestion rate; assimilation of carbon
The feeding response of the blue mussel Mytilus trossulus exposed to environmentally relevant seston matrices were studied in the laboratory under flow-through conditions. Twelve seston matrices varying in quality and quantity were prepared by mixing 3 microalga Thalassiosira pseudonana (5, 20 and 150 x 10(6) cells l(-1)) and 4 silt concentrations (0, 5, 20 and 50 mg l(-1)) to represent an increasing seston organic quality of 10 to 71% and an increasing seston quantity of 1.4 to 56.6 mg l(-1). Clearance rates (CRs), pseudofaeces (PF) production, sorting efficiency (SEF), ingestion rates (IRs) of particulate organic matter (POM) and particulate inorganic matter (PIM) and apparent and true carbon assimilation efficiencies (C-AE%) were determined for the various exposure regimes. Under conditions of 0 and 5 mg l(-1) silt, CRs decreased by 3-fold [14.4 to 4.9 l h(-1) g(-1) dry wt (gdw(-1))] and 6-fold (18.0 to 3.3 l h(-1) gdw(-1)) respectively, with increasing seston quality. Under conditions of high silt loads (20 and 50 mg l(-1)) CRs were independent of increasing seston quality with maximum CRs (21.8 +/- 2.2 l h(-1) gdw(-1)) observed at the 20 x 10(6) cells l(-1) and 20 mg l(-1) silt exposures. PF production was dependent on seston quantity (r(2) = 0.63; p < 0.05) with mussels preferentially rejecting the inorganic versus the organic component of the seston. This SEF was optimized at a seston quality of 40 % organic matter. As a consequence of this selective feeding strategy, determined POM IRs under high algae/high silt (high quantity/quality) exposure regimes were comparable to those of the high quality Oust algae) exposures (POM IRs of 48.0 as compared to 38.1 and 91.3 mg h(-1) gdw(-1) for high quality and high quantity/quality respectively). In contrast, mussels exposed to low quality/quantity seston ingested both seston components (SEF <24%), i.e. the mussel was non-selective, possibly ingesting both seston components to meet nutrient requirements. Apparent C-AE% expressed as C-seston - C-faeces/C-seston correlated with seston quality (% POM) (r(2) = 0.64, p < 0.05). However, carbon assimilation expressed as a true C-AE%, C-diet - C-faeces/C-diet, was independent of seston quality as was carbon assimilation rate (the product of the amount of ingested organic matter and carbon assimilation efficiency). Hence, through a dynamic interplay between CRs and carbon assimilation efficiency, the blue mussel was able to maintain a constant rate of carbon assimilation, regardless of the quality and quantity of seston to which it was exposed. This compensatory feeding strategy displayed by the blue mussel has important implications for predictive models which relate contaminant uptake to a diet/energy pathway. Contaminant uptake may be either underestimated or overestimated if the ability of the blue mussel to optimize nutrient gain under a variety of seston compositions has not been taken into account.
3. BendellYoung, L; Pick, FR. (1997) Base cation composition of pore water, peat and pool water of fifteen Ontario peatlands: Implications for peatland acidification.Water Air and Soil Pollution 96: 155-173 Base cation composition of pore water, peat and pool water of fifteen Ontario peatlands: Implications for peatland acidification
base cations; peatlands; pore waters
Base cation (Ca, Mg, Na, K) concentrations in surface waters, pore waters and surface peats were determined along a mineral-poor to mineral-rich fen gradient for 15 south-central Ontario peatlands. Surface waters of the peatlands ranged in pH and alkalinity from 4.5 to 6.3 and 0 to 181 mu eqL(-1), respectively. Both surface water and pore water Ca and Mg concentrations followed the expected decrease along the mineral-rich to poor-fen gradient. Surface water concentrations of Ca and Mg were significantly lower in the mineral-poor versus the moderately-poor and mineral-rich fens (P < 0.05, ANOVA). Pore water concentrations of base cations were 3-5 fold less in mineral-poor vs. mineral-rich fens. In contrast to surface and pore waters, peat base cation concentrations did not decrease along the mineral-rich to mineral-poor fen gradient. Surface peat base cation concentrations were also independent of pore water cation concentrations, and local bedrock geology. Relative concentrations of base cations in surface peats of all peatlands were best described by the exchangeable cation capacity of the surrounding soils.
2. Lai, JWS; Pinto, LJ; Kiehlmann, E; BendellYoung, LI; Moore, MM. (1996) Factors that affect the degradation of naphthenic acids in oil sands wastewater by indigenous microbial communities.Environmental Toxicology and Chemistry 15: 1482-1491 Factors that affect the degradation of naphthenic acids in oil sands wastewater by indigenous microbial communities
naphthenic acids; oil sands; carboxylic acids; biodegradation; mineralization
The acute toxicity of wastewater generated during the extraction of bitumen from oil sands is believed to be due to naphthenic acids (NAs). To determine the factors that affect the rate of degradation of representative NAs in microcosms containing wastewater and the acute toxicity of treated and untreated wastewater, the effects of temperature, dissolved oxygen concentration, and phosphate addition on the rate of (CO2)-C-14 release from two representative naphthenic acid substrates, (linear) U-C-14-palmitic acid (PA) and (bicyclic) decahydro-2-naphthoic acid 8-C-14 (DHNA), were monitored. Tailings pond water (TPW) contained microorganisms well adapted to mineralizing both PA and DHNA: PA was degraded more quickly (10-15% in 4 weeks) compared to DHNA (2-4% in 8 weeks). On addition of phosphate, the rate of NA degradation increased up to twofold in the first 4 weeks, with a concurrent increase in the rate of oxygen consumption by oil sands TPW. The degradation rate then declined to levels equivalent to those measured in flasks without phosphate. The observed plateau was not due to phosphate Limitation. Decreases in either the dissolved oxygen concentration or the temperature reduced the rate. Phosphate addition also significantly decreased the acute toxicity of TPW to fathead minnows. In contrast, Microtox(R) analyses showed no reduction in the toxicity of treated or untreated TPW after incubation for up to 8 weeks at 15 degrees C.
1. Laurinolli, M; BendellYoung, LI. (1996) Copper, zinc, and cadmium concentrations in Peromyscus maniculatus sampled near an abandoned copper mine.Archives of Environmental Contamination and Toxicology 30: 481-486 Copper, zinc, and cadmium concentrations in Peromyscus maniculatus sampled near an abandoned copper mine
Concentrations of zinc, copper, and cadmium were determined in soil and liver, kidney, bone and stomach contents of deer mice (Peromyscus maniculatus) from two sites near an abandoned mine and one control site, on Vancouver Island, British Columbia, Canada. Soil concentrations of copper were significantly elevated at the mine and off site vs the reference site. In contrast, there was no difference in soil cadmium and zinc concentrations between the mine and reference site. Concentrations of copper, cadmium and zinc in livers of mice from the mine site were significantly elevated relative to the reference and off site locations. Cadmium kidney concentrations tended to be greater in mice from the mine versus the off site and reference site. No differences in bone cadmium, copper and zinc and, kidney copper and zinc concentrations were noted among mice from the three locations. Diet of mice from mine and off sites contained significantly greater copper concentrations than the reference population; no differences in cadmium or zinc diet concentrations in mice from the three sites were noted. Comparison of ratios of metal concentrations in diet:soil and concentrations in liver:soil suggest that for zinc and copper, soil and diet are of equal importance as a source of metal contamination to these mice. In contrast, cadmium diet:soil and cadmium liver:soil ratios were much greater than one indicative of bioconcentration of cadmium from soil to diet and from soil to liver. For assessing routes of metal exposure, in this case for deer mice inhabiting an abandoned mine site, for copper and zinc, soil will most likely be indicative of exposure conditions. In contrast, concentrations of cadmium in diet will be more representative of amounts that the animal is potentially ingesting. Of further importance is that relative to reference sites, mice inhabiting an abandoned copper mine site have significantly elevated tissue levels of copper. This is turn will provide a route of metal exposure to carnivorous birds such as owls and hawks. The toxicological significance of this exposure to birds of prey has yet to be assessed adequately.
