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Bishop et al. ( 1995 ; 1999 ) found good correlations between a variety of chlorinated hydrocarbons in the sediment and concentrations in bird eggs . Selenium concentrations in bird eggs and livers generally were in the range of uncertainty regarding biological risk ; however , some samples from the Uncompahgre Project area had selenium concentrations in the high-risk category . Residue concentrations in osprey eggs for most contaminants did not vary significantly among the river segments ; however , eggs collected in the segment immediately below Bonneville Dam contained significantly higher concentrations of polychlorinated biphenyls ( PCB ’ s ) , a chemical banned decades ago , compared to eggs collected in segments farther upstream and downstream . Mercury concentrations in mallard eggs and total organochlorine concentrations in western grebe eggs were high enough to be of concern for the nesting success of these birds . The Ohio State University Research Foundation will receive $ 10,000 for a study of vitamin concentrations in walleye eggs and the influence those concentrations have on embryo survival .