Passive sampling devices (PSDs) present many advantages over conventional aqueous samples for quantifying hydrophobic organic compound (HOCs) concentrations in pore water (sediment and soil), surface water and storm water in terms of cost and data usability.
They provide data to estimate contaminant bioavailability and toxicity to environmental receptors that is more representative than conventional grab samples, as it quantifies contaminants only in the dissolved form. In the field, PSDs enable collection of representative- and depth-discrete data without the need to collect large volume aqueous samples. Similarly, in laboratory treatability studies to evaluate remedial options for contaminated sediments or soils, passive samplers help to decrease the volume and number of samples required. Passive samplers deployed in these studies provide the ability to compare different treatment technologies in a relatively short time frame, test multiple conditions concurrently, and enable the flexibility to allow changes to a remediation strategy that would be impractical at field-scale.
This presentation will highlight the benefits of using PSDs in both laboratory treatability studies and field applications as well as discuss the practical lessons learned from applying passive sampling techniques, drawing from several case studies using a commercially-available PSD. In one study, PCB availability of a sediment amended with activated carbon, zero valent iron, siderite and sulfur was measured with PSDs. The results were used to determine the most effective commercial amendment for decreasing PCB concentrations in pore water, with PSDs demonstrating that the selected remedy achieved a >95% reduction in PCB availability. In another study, PSDs were used to characterize PCB concentrations in sediment pore water amended with different amounts of activated carbon and the results were used to determine the optimal dose of carbon for the field application, with PSDs demonstrating that the optimal activated carbon application rate resulted in a 98% reduction in PCB availability. At this same site, PSDs were deployed in the field to provide baseline PCB availability data prior to activated carbon amendment, and the PSDs will be used for post amendment monitoring to document remedial success. It is clear that currently-available passive sampling approaches are ready for widespread application and can provide high-quality data to aid environmental decision makers.