Whenever dredged materials are disposed into the ocean, the potential effects of the materials on human health, fishery resources, and marine ecosystems may range from being negligible or unmeasureable to important. Because these effects may differ greatly at each dredged material extraction or disposal site, each site must be evaluated on a case-by-case basis. In the United States, the manual entitled Ecological Evaluation of Proposed Discharge of Dredged Material into Ocean Waters: Implementation Manual for Section 103 of Public Law 92.532 (Marine Protection, Research, and Sanctuaries Act of 1972) (the 'Implementation Manual' or 'Green Book') was published in 1977 to give guidance on determining the potential biological effects caused by dredging operations. The Green Book provides detailed guidance on the conduct of the required bioassays on the liquid, suspendEd particulate, and solid phases of a dredged material. In addition, guidance is given on how to conduct the bioassays and bioaccumulation tests. The U.S. Environmental Protection Agency (EPA) recently published a manual that gives guidance on the appropriate length of the bioaccumulation tests (i.e., 28 days), recommended teSt speCIes, and conduct of the tests. In the past, the U.S. Food and Drug Administration's 'Action Limits' and international fish and shellfish standards have occasionally been used in the interpretation of dredged material bioaccumulation data. Even though they may be useful in some cases, there are limitations to using Action Limits and international standards when evaluating bioaccumulation test data.