Distribution and Physiological Effects of DDT, DDD and DDE in Penned Double-crested Cormorants (Phalacrocorax a. auritus)

Ecological and trophic distributions of chlorinated hydrocarbon residues in Lake Poinsett, South Dakota were studied. Components of the ecosystem analyzed were water, bottom sediment, zooplankton, benthic algae, crayfish, aquatic insects and fish. Concentrations of aldrin, DDD, DDE, DDT, dieldrin, endrin, heptachlor, heptachlor epoxide, lindane, methoxychlor and toxaphene were determined by gas chromatography and thin-layer chromatography. DDT and its metabolites, DDD and DDE, were the highest residues detected in all trophic levels examined. Heptachlor, heptachlor epoxide, aldrin, dieldrin and lindane were present in the majority of sample types, while neither endrin nor methoxychlor was detected above analytical confidence limits in any sample. Toxaphene was present in only four fish. The DDT complex was found to increase in percentage of total residue with higher trophic levels. A change in ratio of DDT to DDD plus DDE was found with increase in trophic level. While DDT was most abundant in water, fish and bottom sediment had greater concentrations of DDD plus DDE. Higher trophic levels had greater percentages of the epoxide form of heptachlor and aldrin. Water had the lowest total residue reported. Bottom sediment and crayfish had 18 times the residue level of water, while zooplankton and benthic algae showed a 37-fold increase over water. Total residue in fish averaged 790 times that of water, and aquatic insects had the highest magnification over water (7300-fold). Analysis of fish tissue gave the order of increasing residue concentration as testes, muscle, liver, egg and depot fat. Fish fat content was correlated (r = 0.40, df. = 72) with higher insecticide levels. Analysis of variance ·showed residue levels increased with age (P \u3c .05). No significant difference was found by analysis of variance between sexes, or between fall and spring collections. Residue levels in Lake Poinsett water were similar to levels reported for other areas, but fish displayed a much lower magnification over water than has been reported in the literature. DDT complex levels detected in Lake Poinsett fish were well below the Food and Drug Administration\u27s tentative 5 ppm tolerance limit set on a wet-weight, whole-body basis. No residues were found above tentative Food and Drug Administration tolerance limits in any sample