108 Russell J. Hall, Ray E. Ashton, Jr., Richard M. Prouty 



Residues were quantified using a gas-liquid chromatograph equipped 

 with an electron-capture detector and a 1.5% OV-17/ 1.95% QF-1 column 

 Residues in 10% of the samples were confirmed by mass spectrometry. 

 Recoveries of pesticides and PCBs from fortified tissues averaged 93%, 

 but residues reported were not corrected for recovery. The lower limit of 

 reportable residues was 0.01 ppm for pesticides and 0.05 ppm for PCBs. 

 All residue levels are expressed on a whole-body wet weight basis. 



Pesticide residues in tissues (Table 1) were of low to moderate lev- 

 els and indicate contamination from a variety of sources. The presence 

 of DDT metabolites (DDD and DDE) and the absence of unaltered 

 DDT suggest that no recent sources of that discontinued pesticide exist 

 in the area. Residues of its metabolites probably are the result of appli- 

 cations made in past years. Both ds-chlordane and trans -nonachlor are 

 constituents of chlordane, a pesticide now used almost exclusively for 

 termite control. 



Table 1. Residues of pesticides and PCBs in Necturus lewisi. 



r n mn rt „ n ^i Geometric mean of Frequency of 

 Compound' residues (ppm)? occurrence 



DDE 

 DDD 



Dieldrin 



cw-chlordane 



fram-nonachlor 



PCB 1254 __ ___ 



1 Heptachlor epoxide, oxychlordane, ds-nonachlor, endrin, toxaphene, HCB, 

 and mirex were not detected at the 0.01 ppm level of sensitivity. 



2 Calculated on a whole-body wet weight basis; only those with measurable 

 residues were used in calculation of means. 



Higher levels of DDE were found in Coastal Plain animals than in 

 those from Piedmont Plateau localities, and they occurred more fre- 

 quently in larger animals (> 30 g) than in smaller ones (< 30 g). Speci- 

 mens from the Coastal Plain averaged 0. 1 1 ppm DDE, while those from 

 the Piedmont averaged 0.02 ppm. Similarly, larger individuals averaged 

 0.15 ppm while smaller ones averaged 0.04 ppm. Two-way analysis of 

 variance shows that both trends are significant (p < 0.05). Dieldrin 

 residues were common in Coastal Plain specimens (frequency = 0.67), 

 but absent from Piedmont specimens. They also were more common in 

 larger specimens than in smaller ones (frequencies 0.6 and 0.2, respec- 

 tively). Components of chlordane showed a pattern similar to that of 

 dieldrin, with greatest contamination in specimens from lowland sites. 



0.06 



1.0 



0.04 



0.7 



0.02 



0.4 



0.02 



0.7 



0.04 



0.2 



0.39 



1.0 



