ABSTRACT
A critical element of water quality impairment is the presence of trace toxic and bioaccumulative pollutants such as chlorinated pesticides, flame retardants, and metals such as mercury. These pollutants cause impairment to ecosystems through accumulation in the aquatic food web and eventually impact human health through fish consumption. The long-term persistence of these pollutants makes the problem even more acute because the impacts last for many decades after the pollutants have been released into the environment. This is true for mercury and several old pesticides such as DDT and flame retardants such as polychlorinated biphenyls. Accurate measurement of pollutant concentrations in relevant phases and predictive models for bio-uptake are required to perform a quantitative assessment of risk to the ecosystem and human health.
Traditional approaches for measuring water pollutants have involved collecting grab samples of water and performing extractions and measuring the target pollutants. This approach has several challenges, including sampling large volumes to meet detection limits and interference due to association with suspended particulates and dissolved ligands in the water. Research in the last decade has led to the increasing use of passive sampling to measure trace levels of hydrophobic organic compounds in water. This approach involves allowing a polymeric sorbent to sample the target pollutants from the water environment over time and then extracting and measuring the pollutants in the sampler to interpret a time-averaged concentration in the field. This chapter provides an overview of the passive sampling approach used in the time-integrated measurement of trace levels of hydrophobic pollutants in the environment. The chapter also describes some of the ongoing research and remaining challenges in the field of passive sampling.
