Zabik, 1973), Starrett's results indicate that organochlorine pesticide 

 levels in the Illinois River were fairly low in 1966. 



The U. S. Fish and Wildlife Service has analyzed fish taken from 

 the Illinois River at Beardstown (mile 88.0) for pesticides, as part of 

 the Nationwide fish monitoring program. Fish have been collected for 

 analysis once or twice a year since 1967. Whole fish are analyzed, and 

 the results are expressed as milligrams of pesticide per kilograms wet 

 weight of the whole fish. The results for the years 1967 through 1969 

 are summarized in Table 36. Inconsistencies were apparent in the results 

 reported by five different laboratories on subsamples of the same fish 

 homogenate in 1967 and 1968 (Henderson, et al., 1969). For example, the 

 analyses of DDT and its metabolities in bigmouth buffalo from the 

 Illinois River ranged from .05 to .54 ppm — an order of magnitude dif- 

 ference (Henderson, et al . , 1969). Nevertheless, Henderson, et al. 

 (1971) felt that the 1969 values for DDT and dieldrin were reliable. 

 Henderson, et al. (1971) did not place much significance on the results 

 of heptachlor and heptachlor epoxide and the results from these com- 

 pounds are not reported in Table 36. Food and Drug Administration 

 limits for dieldrin in fish were exceeded in carp, bigmouth buffalo, and 

 channel catfish from the Illinois River. 



The possible adverse effects on fish and wildlife of the pesticide 

 and mercury levels reported in Table 36 are largely unknown. Lubinski, 

 et al. (1974) reported that aldrin was present in the Kankakee River 

 (a tributary of the Illinois) at concentrations ranging from 0.34 to 

 3.00 micrograms per liter, and that this represented approximately 

 13 percent of a lethal concentration for bluegills . Pesticide levels 

 which are too low to have a direct effect on fish may affect fish-eating 

 birds or other animals. 



Snails ( Physa sp.) which were reared in the laboratory under con- 

 ditions designed to reduce their exposure to pesticides as much as 

 possible, rapidly accumulated dieldrin when exposed in cages to Illinois 

 River water at mile 87 and mile 120 for a period of 8 days in August 

 1974. The snails at mile 87 increased in dieldrin content from 



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