299 



ANALYTICAL PROCEDURES 



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

 epoxide, toxapliene, metlioxychlor, dieldrin, endrin, and the o, p' and p,p' isomers 

 of DDE, DDD, and DDT. Tissues were tliawed 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 concentrated and partitioned with acetoni- 

 trile. The acetonitrile was evaporated just to dryness and the residue diluted 

 from a Florisil column {3). The sample was then identified and quantified by 

 electron capture gas chromatography. Three columns of different polarity (DC 

 200, QF-1, and mixed DC 200 and QF-1) were used to confirm identification. 

 Operating parameters on Varian Aerograph 204 and 610D gas chromatographs 

 were as follows : 



Columns: 5' x %" (O.D.), pyrex glass, packed with 3% DC-200, 5% QF-1, 

 and a 1 : 1 ratio of 3% DC-200 and QF-1, all on Gas Chrom Q. 

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

 Carrier Gas : 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. 80-859'o ; p, p'-DDD (TDE), 

 82-95% ; p, p'-DDT, 91-95% ; and dieldrin, 85-90%. The lower limit of sensitivity 

 was 0.010 ppm (mg/kg dry weight). Data in this report do not include a correc- 

 tion factor for percentage recovery. Polychlorinated biphenyls (PCB) as reported 

 by Holden and Marsden (2) were not detected in these samples. 



RESULTS 



Some form of pesticide was found in all 30 of the seals examined, and 3 of the 

 7 fetuses had measurable amounts of pesticide (Table 1). The largest concentra- 

 tion of any pesticide in an individual was in the liver of a male yearling taken on 

 February 20. 1969 (5.1 ppm DDE). Tissue samples from males and females 

 collected in February and March 1969 contained larger concentrations of pesti- 

 cides, on the average, than those from males collected in July 1968, but some 

 overlap occurred. Of 30 samples of liver tissue from seals other than fetuses, all 

 contained DDE ; 21, DDD ; 24, DDT ; and 3 contained dieldrin. Of the 30 brain 

 samples, all contained DDE ; 5, DDD ; 4, DDT ; and none contained dieldrin. 

 DDE was present in liver tissue from three of the seven fetuses and in brain tit- 

 sue from two. DDD, DDT, and dieldrin were absent in fetal liver and brain. 



