Chemical concentrations are often the first line of evidence in determining sediment quality, yet they tell only part of the story. Chemical values provide an idea of the entire amount of a constituent within a sample, but do not elicit what portion of the contaminant is available for uptake by organisms (bioavailable) and may be capable of causing adverse effects.
In sediment quality assessment, a number of methods have been developed to relate measured chemical concentrations to observed biological effects. None of the approaches alone consistently provides a highly reliable and accurate measure of chemical exposure; therefore, chemistry data is usually integrated with toxicity and benthic community information to assess sediment quality. This multiple lines of evidence (or MLOE) approach provides a better level of confidence in the assessment of sediment quality.
SCCWRP researchers have developed, calibrated, and evaluated the accuracy of a number of approaches for relating measurement of chemical concentrations to sediment toxicity and benthic community degradation. This work utilized a large database of California sediment samples, matching chemistry, toxicity, and benthic community data that was compiled from numerous monitoring and research studies.
For more information on this topic, please contact Steve Bay at steveb@sccwrp.org