PARENT SESSION
Oral Session #26: Aquatic Ecology: Fish - Populations, life history, autecology. Presiding: M. Fox.
Tuesday, August 7, 2001. 8:00 AM to 12:00 PM. Hall of Ideas H.

Contaminants in fish of Illinois inland lakes, 1974-1998.

Jenkins, David¹, Range, Lance¹, ¹

ABSTRACT- Fourteen contaminants in multiple fish species from 149 inland lakes have been quantified by ILEPA for over two decades (1974 to present). In the first synoptic examination of this data set to date, we analyzed for trends in contaminants over time, and among fish species, lakes and regions of the state. Organochlorine contaminants have become more frequently detected in fish over time, despite consistent detection limits for most compounds, likely due to improved laboratory methods over the years. In contrast, mercury contamination has decreased over time. Most detectable levels of contaminants are below health advisory values. However, sampling effort for fish contaminants has varied widely through the years and among lakes. The mid 1970's saw a large sampling effort, but fewer than 200 fish samples statewide have been collected and analyzed each year since 1985. Also, sampling effort varies widely among lakes and is not clearly related to evidence of contamination. These patterns lead to great uncertainty in the adequacy of public fishing advisories and contribute to difficulties in assessing fish contaminant trends in Illinois. A much larger and systematic sampling and analysis effort will be required to assure confidence in the risk assessment of eating Illinois fish.

KEY WORDS: fish contaminants, long-term trend analysis, organochorines and mercury, sampling and risk assessment