Sediment pore water concentrations of polychlorinated biphenyls (PCBs) in a contaminated mudflat in San Francisco Bay, CA were determined by field-deployed polyethylene devices (PEDs). Sequential sampling of PEDs deployed in the field showed large differences in uptake rates and time to equilibrium compared to PEDs mixed with field-collected sediment in the laboratory. We demonstrate a modeling approach that involves the use of impregnated performance reference compounds (PRCs) and interpretation of the data either by PCB molar volume adjustment or environmental adjustment factors to measure pore water concentrations of 118 PCB congeners. Both adjustment methods predicted comparable sampling rates, and PCB pore water concentrations estimated by use of the molar volume adjustment method were similar to values analytically measured in pore waters from the laboratory and field. The utility of PEDs for sampling pore water in the field was evaluated at a tidal mudflat amended with activated carbon to sequester PCBs. Pore water concentrations decreased up to 60% within 18 months after activated carbon amendment, as compared to a mechanical-mixed control plot Results of this study illustrate PEDs provide an inexpensive, in situ method to measure total PCB contamination in sediment pore water using a small set of PRCs.
"One study with POM was recently performed successfully by Oen et al. (2011), but studies on the utility of PRCs for use with PDMS and POM have been limited so far (Reible and Lotufo 2012). Alternatively, equilibrium in the field can be established by performing 2 different thickness samplers (Reible and Lotufo 2012) or by time series deployment (Tomaszewski and Luthy 2008), staggering the removal schedule of individual samplers over a period within which the establishment of equilibrium can be expected. Assessment of equilibrium for in situ exposures can be time‐ consuming and costly and should be considered at the beginning of the planning process for passive sampler deployment. "
"Although stable isotope labeled analogs are preferred, nonlabeled structural analogs that are not present in the sampled matrix may also be used as PRCs (e.g., unusual PCBs congeners when sampling for PCBs). PRC‐based calibration has been successfully used for disequilibrium corrections in field passive sampling of sediments (Booij et al. 2003; Tomaszewski and Luthy 2008; Fernandez, Harvey et al. 2009; Fernandez, MacFarlane et al. 2009; Oen et al. 2011). The application of PRCs for disequilibrium correction requires additional effort, but can ultimately be integrated within gas chromatography–mass spectrometry (GC‐MS) analysis to reduce time and costs because measurement , equilibrium confirmation and disequilibrium correction can be done with only 1 sampler at each location. "
"For samplers of identical surface areas, the uptake rate under static conditions in sediment has been shown to be lower than for sediments that have been mixed. Tomaszewski and Luthy (2008) found lower contaminant accumulations in PSMs under field conditions than in the laboratory, but they were able to adjust for this difference using performance reference compounds. Because contaminants accumulated by a PSM constitute an extract from the sediment in which the PSM was deployed, some factors cause uncertainties in the rate of transfer of contaminants from the sediment. "
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