Assessing the response of aquatic organisms to short-term exposures to urban runoff

To establish a foundation for interpretation of laboratory-based toxicity testing with field-based studies, the laboratory-based testing is compared with in situ testing using caged organisms, or field bioassessments. Test application results indicate different degrees of concordance between tests in measured degree of toxicity; some tests give consistently similar results whereas others show more complex and variable patterns. Toxicity testing in single events may not be predictive of long-term effects in receiving waters, but multiple event analysis provides information on sources and variability of toxicity that is useful in watershed management.