8. 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
7. 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
6. 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
5. 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
4. 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.
3. 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.
2. 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.
1.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.
