Caged vs. resident mussels (Elliptio complanata) as biomonitors of metal pollution in the St. Lawrence River
- Environment Canada, Burlington, Ontario (Canada)
Freshwater mussels (E. complanata) from Balsam Lake ON were caged for 12 weeks at three sites of differing pollution status in the St. Lawrence River. Upon retrieval of cages, resident mussels of the same species were also collected. Ten caged and 10 resident mussels per site, plus 10 pre-exposure animals, were individually analyzed for residues of 10 metals in their soft tissues. Caged mussels adjusted their body burdens of Cd, Fe, Mn, Hg and especially Al and Ni to resemble those in resident mussels from the same sites. For example, Ni increased from a pre-exposure concentration of 1.7 {micro}g/g dry weight to 3.5--5.3 in caged vs. 3.5--5.0 in resident mussels. In contrast, Cr did not increase (6.4 {micro}g/g pre-exposure vs. 6.3--7.9 in caged and 11.0--28.0 in resident mussels). Copper, Pb and Zn did not vary significantly among Balsam Lake, caged or resident mussels. Data on caged mussels suggested that differences in contamination among the three study sites were minimal and involved only three metals (Al, Cd and Cu). However, data on resident mussels showed that there were significant differences among sites for 8 of the 10 tested metals (all except Al and Zn). For most metals, pre-exposure and caged mussels differed in the variability of their individual body burdens, whereas caged and resident mussels were more similar. This provides further evidence that caged mussels attempted to adjust their body burdens of metals to reflect pollution conditions at the exposure sites. These results suggest that caged mussels would be less sensitive than resident mussels as biomonitors of spatial trends in metal pollution in the St. Lawrence River.
- OSTI ID:
- 367444
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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