What Lies Beneath
Technology promises to accurately and quickly assess the threat of toxic organic chemicals in sediment

Challenge
Harbor and river sediment polluted by toxic organic chemicals such as polychlorinated biphenyls (PCBs) is a persistent problem that threatens human health and coastal ecosystems around the country. A portion of these organic pollutants are dissolved in the water permeating sediment and are “bioavailable”—and therefore a threat—to marine life and people that consume seafood. The remaining pollutants bind tightly to sediment particles, which prevents them from entering the food chain. Traditional methods of monitoring sediment pollution are slow, costly, and unable to assess the percentage of organic pollutants that are actually bioavailable. Coastal managers need a sound, reproducible method to determine the potential bioavailability of organic pollutants in sediment so they can pinpoint those sites in greatest need of remediation and restoration.

Response
With support from CICEET, researchers at the Southern California Coastal Water Research Project (SCCWRP) are developing a cost-effective, fiber-based sampler that monitors the bioavailability of organic pollutants in situ, or in the sediment. Unlike bulk sediment chemistry, the most widely used tool to assess sediment, this sensor uses solid phase microextraction (SPME) technology to quantify the bioavailable fraction of organic pollutants in sediment, also known as “porewater concentration.” This enables the user to pinpoint sites with chemicals that could be harmful to aquatic life.

Researchers have begun to demonstrate the SPME sampler’s effectiveness in bench-scale tests. These have shown that porewater concentrations of organic pollutants taken with the sampler were consistent with those measured by more costly, conventional approaches to porewater sampling. Use of the sampler did not impact aquatic life or the ecosystem where the sampling has taken place.

Impact
CICEET researchers have partnered with the California State Water Resources Control Board, which is developing sediment standards and a sediment quality control plan for California’s bays and estuaries. The Board hopes to use the SPME-based sampler technology to replace complicated and costly sediment chemistry in its efforts to assess sediment quality.

In the next series of tests, researchers will compare measurements of the bioavailability of organic pollutants with measures of bioaccumulation in animals living in the same location where the testing is taking place. If successful, the technology has the potential to be applied in any water body where toxic organic chemical pollution in sediment is a problem.

Learn More
Keith A. Maruya
Southern California Coastal Water Research Project (SCCWRP)
T: 714-755-3214
E: keithm@sccwrp.org

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