2019-2020 Executive Summary
The quality of sediment that underlies water bodies is a sentinel indicator of the health of marine ecosystems. Pollutants discharged from wastewater treatment plants and urban watersheds have led to sediment contamination along California’s coastline, with contamination levels most acute in bays and estuaries, where slower-flowing waters promote settling of contaminant-laden particles. SCCWRP has been at the forefront of efforts to quantify, monitor and develop solutions to remediate contaminated sediment. SCCWRP and its collaborators have advanced sediment-quality science into the regulatory arena through the development of a widely applicable sediment quality assessment frameworks. In California, these assessment frameworks are the technical foundation for implementing the state’s Sediment Quality Objectives program. An assessment framework to protect bottom-dwelling organisms went into effect in 2009. A companion framework to gauge the human health impacts of food web contamination due to sediment pollutants was approved for use in 2019.
SCCWRP’s research falls into two main categories that reflect the two main routes by which organisms become exposed to sediment contamination: direct exposure, where bottom-dwelling marine life come into contact with and/or ingests contamination in sediment and/or water, and indirect exposure, where predators accumulate pollutants in their bodies as they consume contaminated prey. Each exposure route calls for a different conceptual approach to build a comprehensive assessment framework that can accurately measure and estimate the impacts of sediment contamination on the organisms exposed to it, including humans. SCCWRP’s goal is to build a common, agreed-upon technical foundation for assessing sediment quality to help water-quality managers make better-informed decisions about sediment remediation and clean-up activities.
This year, SCCWRP is continuing its work across both the direct and indirect exposure arenas, as well as pursuing case studies that can assist in translating water and sediment quality objectives to application by environmental managers. SCCWRP’s focus for 2019-20 will be on:
- Assessing indirect effects on sediment quality: To assess sediment contamination’s health risks for humans and wildlife, SCCWRP is continuing to refine bioaccumulation models and assessment frameworks that integrate chemical exposure and sediment contaminant linkage indicators. In the sediment linkage arena, SCCWRP is using passive sampling and tissue contamination measurements to improve the ability of bioaccumulation models to address the influence of dissolved contamination in the water column on food web contaminant transfer.
- Implementing sediment and water quality objectives: To support implementation of new evaluation tools for assessing sediment quality impacts on human health, SCCWRP is continuing to update its technical support resources and guidance documents and provide training in the use of sediment quality assessment frameworks. In addition, SCCWRP is conducting a case study to investigate the effects of site-specific water quality factors on copper bioavailability in the water column. The development of site-specific objectives provides environmental managers with a mechanism to ensure that regulatory targets for contaminants will provide the intended level of environmental protection.