US EPA

2199165 

Technical Report 

Significance of chlorinated hydrocarbon residues to breeding pelicans and cormorants 

Anderson, DW; Hickey, JJ; Risebrough, RW; Hughes, DF; Christensen, RE 

1969 

HAPAB/70/00449 

Field 

2 

HAPAB The levels of chlorinated hydrocarbons present in eggs and spring foods of double-crested cormorants (Phalacrocorax auritis ) and white pelicans ( Pelecanus erythrorhynchos ) are reported and the effects of these residues on the reproductive physiology of these species are discussed. Sampling was conducted in the summer of 1965 on 19 lakes and impoundments in 10 watersheds of the prairie states and of provinces of Canada. Pesticides used locally in most of the study areas included most commonly DDT, aldrin, dieldrin, sevin, toxaphene and mercury seed dressings. Industrial pollutants included the polychlorinated biphenyls ( PCBs ). A total of 329 fish were pooled for analysis and 89 cormorant and 54 pelican eggs were collected and analyzed by the methods outlined by the U.S. Food and Drug Administration ( 1965 ). Recoveries, using this procedure, from egg and tissue samples spiked with DDE, TDE, DDT or dieldrin with levels greater than 0.05 ppm were found to be 85 to 100%. In order to seaparate the PCBs from the chlorinated insecticides, five extracts of eggs were randomly selected from the original series, rerun again on the gas chromatographs in 1969, then treated with alcoholic potassium hydroxide and analyzed again by gas chromatography. Results showed that there was no significant PCB interference in the determination of DDE. No fish pools approached levels greater than 0.1 ppm of DDE and no dieldrin values for fish exceeded 0.015 ppm. Heptachlor epoxide, endrin, aldrin and toxaphene were not detected in any of the fish pools. PCB residues were detected in all fish samples in trace amounts. The mean residues for cormorant and pelican eggs were higher than those for fish. Dieldrin, DDE and PCBs were universal in all the egg pools, whereas heptachlor epoxide ( 0.3 to 0.5 ppm ) was detected in only three cormorant egg pools. The highest cormorant and pelican egg residues were 45.0 and 4.8 ppm of DDE and 28 ppm and trace amounts of PCBs, respectively. The residues were low enough to cause no alarm from an acute toxicity point of view. The major interspecific differences between the egg residues in pelicans and cormorants were progably due to dissimilar nonbreeding-area exposures. The correlation coefficients suggest that in both species measurable declines in shell weight and thickness can be related to the lowest residues of DDE and PCB. There does not appear to be a minimum effective level concerning changes in eggshell. In general, the population status of a given colony can be related to the residues and shell thickness of the eggs from that colony. Other ecological factors complicate the situations and probably modify them. MONITORING AND RESIDUES 70/04/00, 142 1969