ACCUMULATION OF METALS, POLYCYCLIC (HALOGENATED) AROMATIC-HYDROCARBONS, AND BIOCIDES IN ZEBRA MUSSEL AND EEL FROM THE RHINE AND MEUSE RIVERS

Concentrations of heavy metals and various groups of organic microcont aminants were measured in zebra mussel and eel from the Rhine-Meuse ba sin. Residues in mussel from the Rhine and Meuse were on average 2.3 a nd 2.9 times higher than in those from the reference location of IJsse lmeer. Total body burdens of organic microcontaminants in mussel and e el varied between 0.05 to 0.07 mmol/kg fat weight in six out of seven samples. The largest contribution in mussels and eel came from polycyc lic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), respectively. Concentrations of bromodiphenylethers, chlorobenzenes, chloronitrobenzenes, chloroterphenyls, and chlorobenzyltoluenes were l ower Total polybrominated biphenyl residues appear lower than total PC B levels. The largest chlorobiocide residues were noted for 4,4'-DDE, toxaphene, trichlorophenylmethane, and gamma-hexachlorocyclohexane. An extraordinary high body burden of 1.2 mmol/kg fat weight, largely con sisting of acenaphthene, was observed in one sample. Ratios of concent rations in organism fat and dry organic suspended solids varied betwee n 1 and 10 for traditionally monitored organochlorines, independent of the octanol-water partition coefficient (K-ow; for K-ow < 10(6)). The values did not deviate significantly from a value of about 3.3, expec ted for equilibrium partitioning of persistent chemicals. Lower values were observed for PAHs and some chloro(nitro)benzenes. Most ratios of concentrations in eel and mussel fat were within the range of 1 to 10 , also largely independent of K-ow. Yet, values tended to be higher at K-ow > 10(6). Ratios below 1 were noted for pentabromodiphenylether, pentachloro(thio)anisol, chlorobenzyltoluenes, and some chloronitroben zenes, chlorobiphenyls, and chlorobiocides. These field data confirm r ecent modeling efforts on bioconcentration and biomagnification. For h eavy metals, atomic mass explained 67% of the variation in zebra musse l residues.