Development of a Novel Equilibrium Passive Sampling Devicefor Methylmercury in Sediment and Soil Porewaters
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Date
2019-11-06
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Citation of Original Publication
Sanders, James P.; McBurney, Alyssa; Gilmour, Cynthia C.; Schwartz, Grace E.; Washburn, Spencer; Driscoll, Susan B. Kane; Brown, Steven S.; Ghosh, Upal; Development of a Novel Equilibrium Passive Sampling Devicefor Methylmercury in Sediment and Soil Porewaters; Environmental Toxicology and Chemistry—Volume 39, Number 2—pp. 323–334 (2019); https://setac.onlinelibrary.wiley.com/doi/full/10.1002/etc.4631
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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0
This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
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Abstract
We explored the concept of equilibrium passive sampling for methylmercury (MeHg) using the strategy developedfor hydrophobic organic chemicals. Passive sampling should allow prediction of the concentration of the chemically labilefraction of MeHg in sediment porewaters based on equilibrium partitioning into the sampler, without modeling diffusionrates through the sampler material. Our goals were to identify sampler materials with the potential to mimic MeHg parti-tioning into animals and sediments and provide reversible sorption in a time frame appropriate for in situ samplers. Can-didate materials tested included a range of polymers embedded with suitable sorbents for MeHg. The most promising wereactivated carbon (AC) embedded in agarose, thiol–self‐assembled monolayers on mesoporous supports embedded inagarose, and cysteine‐functionalized polyethylene terephthalate, which yielded log sampler–water partition coefficients of2.8 to 5 for MeHgOH and MeHg complexed with dissolved organic matter (Suwannee River humic acid). Sampler equili-bration time in sediments was approximately 1 to 2 wk. Investigation of the MeHg accumulation mechanism by AC em-bedded in agarose suggested that sampling was kinetically influenced by MeHg interactions with AC particles and notlimited by diffusion through the gel for this material. Also, AC exhibited relatively rapid desorption of Hg and MeHg,indicating that this sorbent is capable of reversible, equilibrium measurements. In sediment:water microcosms, porewaterconcentrations made with isotherm‐calibrated passive samplers agreed within a factor of 2 (unamended sediment) or 4(AC‐amended sediment) with directly measured concentrations. The present study demonstrates a potential new approachto passive sampling of MeHg.Environ Toxicol Chem2020;39:323–334. © 2019 SETAC