Objective: The objective of this project is to develop and standardize a procedure using solid phase microextraction (SPME) devices for measuring freely dissolved pore water concentrations and to demonstrate the relationship of these measurements to contaminant flux, bioavailability, and bioaccumulation under field conditions. Pore water concentrations drive contaminant flux below the biologically active layer and in contaminated sediment caps, and a method for easily determining these levels would provide a better means of evaluating contaminant migration and release. More importantly, direct measurement of that portion of the contaminant that is freely dissolved has been shown to be an effective tool for determining the bioavailable fraction and predicting bioaccumulation. Technology Description: SPME traditionally has been used for determining aqueous phase concentrations, but work in the laboratory has shown that it can be used for in situ determination of pore water concentrations if appropriately armored and strengthened and if sufficient time is provided for equilibration. This project is designed to determine and demonstrate the optimum approach to implementation of SPME for in situ determination of pore water concentrations and bioavailability of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) in sediments, moving SPME from a successful laboratory tool to a routine field characterization tool. An approach to sampling similar to that used for diffusion samplers or "peepers" in pore water metals analysis is envisioned. Inserting 10-20 centimeter length of SPME into sediments, perhaps with a rigid rod for support and protection, and allowing it to equilibrate for hours or days, depending on the target analyte, would allow high precision profiles of pore water concentrations by analyzing in 0.5-1 centimeter lengths. The demonstration will test the hypothesis that these pore water concentrations directly indicate bioavailabilty and bioaccumulation potential to organisms. Expected Benefits: The expected benefits of this project are an improved ability to determine pore water concentrations and use them as a measure of bioavailability and bioaccumulation. Currently, pore water concentrations are difficult if not impossible to routinely determine for common hydrophobic sediment contaminants. Routine pore water concentration determination, simultaneous with demonstration of the relationship to bioavailability, will improve assessments of potential exposure and risk and the ability to appropriately manage contaminated sediments. (Anticipated Project Completion - 2009) Principal Investigator: Dr. Danny Reible University of Texas at Austin Hazardous Substance Research Center 1 University Station C1786 Austin, TX 78712 Telephone: (512) 471-4642 Fax: (512) 471-5870 E-mail: reible@mail.utexas.edu DoD Liaison: Dr. Jeffery Steevens US Army Corps of Engineers Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Telephone: (601) 634-4199 Fax: (601) 634-0713 E-mail: Jeffery.A.Steevens@erdc.usace.army.mil | 
