tral analysis, which in turn may generate a list of candidate compounds for 

 toxicity testing. Or, the consistent occurrence of a given compound from 

 one location may stimulate a cooperative effort with Fish and Wildlife Ser- 

 vice Regional personnel, as in the cases of recent investigations of DDT in 

 the lower Rio Grande and toxaphene in the Great Lakes, to determine the 

 source and magnitude of the regional problem. And finally, questions aris- 

 ing from the analysis of NPMP samples continue to stimulate the development 

 of new analytical approaches. 



no 



