"Submitted to: Dr. James R. Clark"--Cover Includes bibliographical references (v. 2, pages 402-419).

The acute toxicological hazards of most pollutants are determined by laboratory toxicity tests. Estimates of field impacts or environmental risk assessments are made using extrapolation from laboratory toxicity tests to determine environmentally safe concentrations. A second phase of testing may involve in situ or field toxicity testing. A third and final phase of research is biomonitoring or ecotoxicological studies which use various environmental monitoring techniques to assess impacts on field populations. The integration of these three approaches provides a mechanism for measuring field impacts and validating the accuracy of laboratory toxicity tests in predicting field impacts. The application of this approach to assess impacts from nonpoint source agricultural pesticide runoff from vegetable crops in coastal South Carolina was studied by: (1) conducting laboratory toxicity tests on the most sensitive and ecologically important species endemic to the study area, the grass shrimp (Palaemonetes pugio) and the estuarine mummichog fish (Fundulus heteroclitus); (2) conducting field toxicity tests using a variety of test species including grass shrimp (Palaemonetes pugio), mysid shrimp (Mysidopsis bahia), panaied shrimp (Panaeus aztecus or Penaeus setiferus). Sheepshead mennow (Cyprinodon variegatus) and the mummichop (Fundulus heteroclitus); and (3) bionomitoring (block-seining) of macropelagic fauna (>15mm) at sites where field toxicity tests were conducted.