Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Bill T. Ridgeway


Crayfish were collected from 3 sites on Polecat Creek, Coles County, Illinois in early spring, early summer, and late summer of 1972. Pesticides were extracted from the crayfish tissue in a one step procedure utilizing a Florisil elution column. Analysis was by electron capture gas chromatography. Pesticide residues in the nannogram range were analyzed and background contamination was an important consideration. Sources of background contamination were investigated and teflon stopcocks, Florisil, and residues on “cleaned” glassware were found to be major contamination sources. Distilled water used in flushing glassware should also be considered a potential contamination source.

Aldrin, dieldrin, and ppʹ DDE were identified and quantitated in all samples tested. Heptachlor epoxide was identified in several samples as were peaks that corresponded to either heptachlor or lindane. No ppʹ DDT was found. No significant differences were found in pesticide levels of aldrin, dieldrin, or ppʹ DDE with respect to time or location.