Absorption of hydrophobic contaminants from ingested Chlamydomonas rheinhardtii and Chlorella vulgaris by Zebra mussels, Dreissena polymorpha

The zebra mussel, Dreissena polymorpha, has the potential to influence cont aminant cycling in freshwater systems because of its large population densi ty, high lipid content, and high filtering rate. Ingestion of contaminated particles such as algae dominates exposure routes for the zebra mussel for strongly particle-associated contaminants. However, the data on absorption efficiency are limited and models to predict contaminant accumulation for t he lower food web have identified the absence of such data as limiting and necessary to improve predictions. Accumulation of 2,2',4,4'-tetrachlorobiph enyl (TCBP), 3,3',4,4',5-pentachlorobiphenyl (PCBP), 2,2',4,4',5,5'-hexachl orobiphenyl (HCBP) and 1,1-dichloro-2,2-bis[4-chlorophenyl] ethylene(DDE) w as determined at two algal concentrations from exposures to contaminated Ch lamydomonas rheinhardtii and Chlorella vulgaris. The contaminant absorption efficiencies were determined based on a chemical-mass-balance model. Musse l absorption efficiencies for the four chemicals at the two different algal concentrations for the two algal species ranged from 68.3% to 95.4% and we re independent of algal concentrations and algal species for the same chemi cal.