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Influence of ortho ‐substitution homolog group on polychlorobiphenyl bioaccumulation factors and fugacity ratios in plankton and zebra mussels ( Dreissena polymorpha )
Author(s) -
Willman Eric J.,
Manchesterneesvig Jon B.,
Agrell Cecilia,
Armstrong David E.
Publication year - 1999
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620180706
Subject(s) - bioaccumulation , congener , zooplankton , bioconcentration , biomagnification , dreissena , phytoplankton , zebra mussel , environmental chemistry , trophic level , plankton , biology , chemistry , ecology , bivalvia , mollusca , mussel , nutrient
The accumulation of a set of non‐ and mono‐ ortho (coplanar) PCB congeners in aquatic ecosystems is of interest due to their dioxin‐like toxicities. Chemical properties (octanol‐water partition coefficients) suggest that the coplanar congeners may accumulate in organisms to a greater extent than homologs with greater ortho substitution. We analyzed a set of 65 PCB congeners with zero to four ortho ‐chlorines from seven homolog groups in water, suspended particulate matter, and zebra mussels from Green Bay, Wisconsin, USA, on four dates throughout the ice‐free season. The suspended particulate matter was separated by size and characterized as phytoplankton or zooplankton using diagnostic carotenoid pigments and light microscopy. Median bioconcentration factors (BCFs) for accumulation from water by phytoplankton and bioaccumulation factors (BAFs) for accumulation from water plus food by zooplankton and zebra mussels ranged from 1 × 10 4 to 1 × 10 6 and were generally the greatest for the tetra‐ to heptachlorobiphenyls. The average coplanar congener BCFs and BAFs for accumulation from water by phytoplankton, zooplankton, and zebra mussels for the tri‐, tetra‐, and pentachlorobiphenyls were 54% larger than corresponding values for their homologs. Biomagnification factors (BMFs) of the tetra‐, penta‐, and hexachlorobiphenyls between zooplankton and zebra mussels and their food source, phytoplankton, typically ranged between 1 and 10, but the average coplanar congener BMFs were 25% less than values for their corresponding homologs. The tendency for coplanar congeners to accumulate to a lesser extent between trophic levels was not as large as their tendency to accumulate from water to a greater extent. Based on accumulation factors, we conclude that the dioxin‐like tetra‐ and pentachlorobiphenyls generally accumulate in the phytoplankton, zooplankton, and zebra mussels of the Green Bay ecosystem to a greater extent than other congeners. Fugacity ratios suggest that, in phytoplankton and zooplankton, homolog concentrations were below equilibrium with water throughout the field season, particularly for the more chlorinated groups, but that concentrations in zebra mussels were at or above equilibrium with water.