Demonstration and Evaluation of Solid Phase Microextraction for the Assessment of Bioavailability and Contaminant Mobility

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Unlimited The goal of the project was to develop and standardize a procedure using field deployable solid phase microextraction (SPME) for the measurement of freely-dissolved porewater concentrations of hydrophobic organics and demonstrate the relationship of these measurements to contaminant flux, bioavailability and bioaccumulation. The goal of the project was to develop and standardize a procedure using field deployable solid phase microextraction (SPME) for the measurement of freely-dissolved porewater concentrations of hydrophobic organics and demonstrate the relationship of these measurements to contaminant flux, bioavailability and bioaccumulation. Specific objectives of the PDMS technology for hydrophobic organic compounds include: Determination of mobile and available contaminants in sediments Assessment of bioaccumulation potential in benthic organisms Assessment of vertical chemical profiles in surficial sediments and sediment caps The work was conducted in sediments both in laboratory and field testing. Laboratory testing allows sediments to be collected and tested in the laboratory, avoiding problematic field deployments where placement and retrieval is too difficult or costly. This testing also allows coupling of availability measurements with laboratory bioassays under controlled conditions avoiding the difficulties and variability of field bioassays. The field testing allows determination of availability and cap performance under conditions that might not be reproducible in the laboratory. All porewater measurements herein were measured in-situ (i.e. in sediments whether field or lab) and require no porewater separation from the sediments prior to analysis. 1.2. TECHNOLOGY DESCRIPTION In-situ solid-phase microextraction (SPME) is a passive sampling approach for measuring hydrophobic organic contaminants in porewater and involves the insertion of a polymer sorbent into the sediments, withdrawal after a period of time, preferably after achievement of equilibrium, and measuring the contaminants sorbed to the polymer. The contaminant concentration that accumulates in the polymer sorbent at equilibrium is directly …