Measuring bioaccumulation of contaminants from field-collected sediment in freshwater organisms: a critical review of laboratory methods.

To be effective, decision-making frameworks require data from robust and reliable test methods. Using standard methods allows for more effective comparison between studies and application of data, and it reduces unnecessary duplication of efforts. Laboratory methods to assess the toxicity of sediment have been standardized and extensively used; however, procedures for measuring the bioaccumulation of contaminants from sediment into aquatic organisms need further standardization. Bioaccumulation methods using freshwater invertebrates and fish exposed to field-contaminated sediment were reviewed to identify important similarities and differences in method protocols, test conditions that need to be controlled, and data gaps. Although guidance documents are available, great variation still exists in exposure techniques used in tests, which may potentially affect the estimation of bioaccumulation. The techniques most consistent across studies include the use of Lumbriculus variegatus as a test species, test temperatures between 20 and 25°C, and a 28-d exposure with no addition of food, followed by purging of organisms. Issues that were inconsistent between studies or remained unspecified, which should be addressed, include the bioaccumulation potential of other test species, loading density of organisms, and sediment-to-water ratio. In addition to proper evaluation of the various exposure techniques and conditions, a need exists for more consistent inclusion of quality control procedures during testing.