303 



INTRODUCTION 



compounds are resistant to chemical brealidown by digestive and physiological 

 processes in mammals, birds, and fish (3). Pesticide residues have been found 

 in blubber, brain, and other body tissues of marine mammals in Antarctica (4, 

 J2) and in gray seals, Halichoerus grypus; common seals, Phoc<i vituUna; and 

 harbor porpoises, Phocoena phocoena, from the coasts of Scotland (7). In addi- 

 tion, juvenile and adult harp seals, Phoca groenlandica, on the Canadian At- 

 lantic coast contained pesticides, principally of the DDT groups (7), as did 

 porpoises examined by Wilson in Florida (vnpiiUished data). Anas and Wilson 

 (i) found DDT and its metabolites and dieldrin in brain and liver samples 

 from the northern fur seal, Cailorhiniis ursinufi. Koeman and van Genderen (8) 

 found 9.6 to 27.4 ppm of DDT and 0.07 to 2.30 ppm of dieldrin in harbor seals 

 in the Netherlands. 



These chemicals, although they mainly affect the nervous system, may after 

 long-term accumulation cause sterility and mortality in adults or mortality 

 among progeny, as observed in pelicans and cormorants (2). They may interfere 

 with steroid hydroxylatiou. resulting in the lowering of calcium deposition in 

 eggshells (C) ; interact in polyunsaturated fatty acid metabolism, resulting in 

 riboflavin deficiency (13) ; and cause degenerative changes in rat liver tissue 

 (10). This report records the amounts of DDT and its metabolites and dieldrin 

 found in the tissues of gray whales, Eschrichtius robustus, and sperm whales, 

 Physeter oatodon. 



SAMPLING 



Samples of brain, blubber, and liver tissues were collected from 23 gray 

 whales taken during migration seasons in March-April 1968, December 1968- 

 January 1969, and March 1969. Similar samples from six sperm whales were 

 taken during May and November 1968. All of the collections were made off 

 San Francisco, Calif. About 100 g of each tissue was collected from each animal. 

 I'issues were frozen from the time of collection until time of analysis. Maturity 

 and reproductive condition were determined by histological examination of the 

 testes and mammary glands and examination of ovaries for corpora lutea and 

 corpora albicanti. 



ANALYTICAL PBOCEDTJKES 



Liver, brain, and blubber tissues were analyzed for BHC, heptachlor, aldrin, 

 heptachlor epoxide, toxaphene, methoxychlor, dieldrin, endrin, and the o,p' 

 and p,p' isomers of DDE, DDD (TDE), and DDT. Tissues were thawed and 

 mixed with anhydrous sodium sulfate in a blender. The mixture was extracted 

 for 4 hours with petroleum ether in a Soxhlet apparatus. Extracts were concen- 

 trated and partitioned with acetonitrile. The acetonitrile was evaporated just 

 to dryness and the residue eluted from a Florisil column (9). Sample extracts 

 were then identified and quantified by gas chromatographs equipped with elec- 

 tron capture detectors. Column packing and operating parameters were as 

 follows : 



Columns: 5' x %", glass, packed with 3% DC-200. 5% QF-1, and a 1: 1 

 ratio of 3% DC-200 and 5% QF-1, all on 60/80 Gas Chrom Q. 

 Temperature: Detector, 210 C ; Injector, 210 C ; Oven. 190 C. 

 Carrier : Prepurified nitrogen at a flow rate of 40 ml/minute. 



A few samples were analyzed using thin-layer chromatography. Laboratory 

 tests gave the following recovery rates : p.p'-DDE, 80-85% ; p.p'-DDD, 92-95% ; 

 ;),p'-DDT, 91-95% ; dieldrin, 85-90%. The lower limit of sensitivity was 0.010 

 ppm (mg/kg. wet weight). Data in this report do not include a correction factor 

 for percentage recovery. Polychlorinated biphenyls (PCB's) reported by Holden 

 and Marsden (7), were not detected in our samples. All values reported were 

 calculated on a wet weight ba.sis. 



DISCUSSION 



DDT and its metabolites were found in 4 males and 2 females of the 23 (26%) 

 gray whales examined (Table 1). All four of the whales taken during .spring 

 1988 contained residues at levels ranging up to 0.058 ppm. In contra.st. only 2 

 of 19 whales sampled during the 1968-69 migration contained pesticides, but 

 DDT and its metabolites were about 5 times more concentrated in these 2 whales ; 

 the highest level was 0.36 ppm. One male and one female gray whale had trace 

 amounts of DDE in the brain tissue. The liver tissue of all the gray whales 

 was free of pesticide.s. Dieldrin was found in all the spring 1968 samples but 

 was lacking in the 1968-69 migration series. 



