As part of a series of Science Advisory Board ongoing reviews on the ORD research program, the SAB reviewed a document entitled 'Reference Material for SAB Review of Water Quality Based Approach for the Control of Toxics - Freshwater'. The document was prepared by four EPA laboratories that carry out research in this particular program. The Subcommittee's major conclusion was that methods for deriving water quality criteria have undergone a steady evolution and extensive scientific review. The scientific and regulatory communities have widely accepted the resulting criteria. Additional Subcommittee recommendations were directed at further strengthening the water quality based approach, and integrating it with work related to other areas of toxic controls needing attention.