To produce a scientifically defensible and holistic sediment assessment, the three lines of evidence related to sediment quality (chemistry, toxicity, and biological community) must be evaluated and integrated in a consistent manner. To meet this need, SCCWRP researchers developed an MLOE integration framework that combines the different types of data in a stepwise fashion.
1) To start, the results from each line of evidence to characterize the sediment sample are placed into the following categories:
2) Next, the chemistry and biology response categories are each combined with the toxicity category to assess two elements of ecological risk: the severity of adverse biological effects and the potential for biological effects from chemical exposure.
For example, if the benthic community shows a “low disturbance” and the toxicity test displays “moderate toxicity,” then the level of biological effect is classified as “low effect.”
3) The results of these two ecological risk elements are then integrated to determine the overall site condition. The Severity of Biological Effect category (Unaffected, Low, Moderate, or High) and Potential for Chemically-Mediated Effect category (Minimal, Low, Moderate, or High) are compared to determine the final site condition category.
When results from this integration framework were compared to the evaluation of the same data by a group of experts, the framework was found to have comparable accuracy and a low level of bias.
SCCWRP has recently applied this framework to regional monitoring data throughout California to produce a statewide assessment of sediment quality.
For more information on this topic, please contact Steve Bay at steveb@sccwrp.org