These compounds generally are not soluble in water but can accumulate in the tissues of organisms that live in the water. As a result, tissue samples of fish are collected and analyzed for the presence of these compounds. Contaminants on the land surface can be washed into streams, commonly attached to sediment. The contaminants can enter the food chain and bioaccumulate in predator species.
Trace amounts are present in streambed sediment and fish.
Fish are collected for study by a team of biologists using equipment like this barge-mounted electroshocker. Twenty sites were sampled from 1992 to 1995 to determine the occurrence and distribution of selected organochlorine compounds. Whole-body tissue samples of white sucker were collected at 19 of the 20 sites and smallmouth bass were collected at 5 sites. Organic compounds were detected in whole-body fish tissue and the streambed sediment at all 20 sites sampled, which represented a variety of settings. The collection of whole fish and fillet data in future studies would aid in identifying problem sites and evaluating the need for fish-consumption advisories.