Environmental monitoring and remediation action strategies require accurate measurements of the impact of contaminants of concern on terrestrial and aquatic organisms. Discrete sampling of water and sediment followed by laboratory analysis is a standard practice. Total concentration data provided by discrete measurements provides a baseline understanding of contaminant distribution, but provides only limited information on toxicity potential since a total concentration value may not predict to what extent pollutants are accessible to organisms. Passive samplers provide an alternative option to discrete sampling. Typically passive samplers have targeted the collection of trace organic compounds (TOCs), such as PCBs and other non-polar analytes such as PAHs. The integrative nature of passive samplers is useful in obtaining time weighted averages in water streams and increasing concentrations above method detection limits by accumulation over time. Special emphasis has been placed on mimicking the uptake of PAHs and PCBs by benthic organisms in order to illuminate the potential for adverse impacts on aquatic ecosystems without having to use live organisms and tissue extractions. As such, significant research has been accomplished developing biomimetic models, equilibrium models, and devices to simulate bioaccumulation. It is important to understand where contaminants are found in sediments, how source location affects bioavailability, and why passive sample design is critical.
The goal of the project was to utilize ABS Materials, Inc. swellable organosilica media to build and evaluate a passive sampler design that would possess the following attributes:
The technical approach taken to address the objectives was as follows:
The major findings of the project were the following:
The unique aspects of the sampler as designed and tested (i.e. low cost, fast capture rate, wide specificity) could open up new possibilities in sampling to provide data sets to site managers that are currently unavailable. Two examples are the following:
Additionally, the successful completion of this project has resulted in the development and commercialization of the Sentinel™ passive sampler.