Passive Sampling Devices Psds As Biological Surrogates For Estimating The Bioavailability Of Organic Chemicals In Soil PDF Download

Passive sampling devices have been used for decades to measure complex mixtures of bioavailable organic chemicals in a variety of environmental media. More recently passive sampler applications have expanded beyond monitoring chemical concentrations, and this dissertation continues to advance methods of passive sampling on many fronts. Despite their growing use, no practical, evidence-based guidelines exist to ensure concentrations of chemicals sequestered in passive samplers are stable in transport and storage. We demonstrated that concentrations of semivolatile chemicals sequestered within passive samplers would be stable with low-cost shipping from isolated locales by simulating in the laboratory a worst-case scenario at 35 °C for two weeks. Quantitative measures of the flux of semivolatile chemicals between soil and air have been limited by the challenges of collecting soil and estimating chemical fugacity from soil. We avoided these pitfalls by adapting passive sampling equipment to directly sample gas-phase chemicals in air above the soil. The sensitivity of the novel technique was demonstrated at three disparate sites, where volatilization was measured at a site with historically contaminated soil, and deposition was measured at another site with a recent oil spill and fire. In a related study, we deployed the same equipment on artificial turf fields to provide the first quantitative measure of semivolatile flux between artificial turf and overlying air. We detected an additional 26 compounds that have not been previously associated with artificial turf, including some that have known human health impacts. Finally, passive sampling principles were applied to measure chemicals in the human personal environment, using a newly-developed silicone passive sampler wristband. Nineteen pesticides were detected that were not reportedly used among 35 rural farmer participants, demonstrating the utility of the wristband in measuring personal exposures to pesticides. Pesticide concentrations in multiple wristbands, worn by a participant over time, were more similar to each other than to other participants, signifying the uniqueness of personal environments and the importance of taking personalized measurements when assessing risk. The advancements in this dissertation capitalize on the features of passive sampling techniques: easy, yet robust, transport capabilities were demonstrated to provide evidence-based transport criteria; ability to directly measure gas-phase chemicals led to quantitative flux measurements from soil and artificial turf; non-selective organic chemical sequestration allowed for identification of unexpected, or previously unreported chemicals; and the polymer qualities that mimic biological membranes sampled the bioavailable fraction for comparing human exposures. The advancements herein provide logistical solutions and sensitive measures of chemical transport and human exposures, and contribute to the expanding range of possibilities for passive sampling.