Simple polyethylene strip measures the fraction of sediment contamination that poses a risk to ecological receptors and human health.
DoD manages hundreds of contaminated sediment sites in bays, harbors, lakes, wetlands, and rivers. Historically, regulators and site managers have assessed these sites by measuring how much of a specific chemical such as polychlorinated biphenyls is present in the sediment. However, total concentrations are poorly correlated with the toxic impacts that need to be addressed. What is needed is a way to easily and cost-effectively measure the fraction of those chemicals at a particular field site that can be taken up by an organism and cause harm.
Dr. Philip Gschwend and colleagues have demonstrated and validated a commercially viable, simple passive sampler that can measure the fraction of the chemical that is of concern. Developed under SERDP, the passive samplers utilize an inert low-density polyethylene medium to accumulate organic compounds from contaminated sediment beds. The polyethylene concentrations can be converted to contaminant concentrations that are available to the organisms in this environment.
This accurate and robust passive sampling technique can be cost-effectively employed at virtually all DoD contaminated sediment sites to characterize the risk of contaminants entering the food chain. It provides significant savings in manpower, number of days in the field, equipment, and shipping costs as compared to traditional sampling methods. For sites already in the remedial action process, the use of these samplers could significantly reduce the costs of long-term monitoring. Beyond cost reduction, the passive sampling technique can help guide remediation efforts to target the real risk and thus improve the health of the environment at sediment sites across DoD and the nation.
For this work, Dr. Gschwend received a Project-of-the-Year award at the annual Partners in Environmental Technology Technical Symposium & Workshop held November 29 –December 1, 2011, in Washington, D.C.