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Tytuł:
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Mind the Exposure Gaps-Modeling Chemical Transport in Sediment Toxicity Tests.
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Autorzy:
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Fischer FC; Health and Environmental Risk Division, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan.
Hiki K; Health and Environmental Risk Division, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan.
Soetaert K; Department of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute for Sea Research, Korringaweg 7, 4401 NT Yerseke, The Netherlands.
Endo S; Health and Environmental Risk Division, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan.
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Źródło:
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Environmental science & technology [Environ Sci Technol] 2021 Sep 07; Vol. 55 (17), pp. 11885-11893. Date of Electronic Publication: 2021 Aug 16.
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Typ publikacji:
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Journal Article; Research Support, Non-U.S. Gov't
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Język:
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English
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Imprint Name(s):
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Publication: Washington DC : American Chemical Society
Original Publication: Easton, Pa. : American Chemical Society, c1967-
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MeSH Terms:
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Geologic Sediments*
Water Pollutants, Chemical*/analysis
Water Pollutants, Chemical*/toxicity
Environmental Monitoring ; Toxicity Tests ; Water
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Contributed Indexing:
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Keywords: bioavailability and exposure; diffusion and partitioning; facilitated transport; laboratory−field extrapolation; numerical modeling; sediment toxicity
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Substance Nomenclature:
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0 (Water Pollutants, Chemical)
059QF0KO0R (Water)
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Entry Date(s):
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Date Created: 20210907 Date Completed: 20210923 Latest Revision: 20210923
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Update Code:
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20240105
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DOI:
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10.1021/acs.est.1c03201
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PMID:
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34488347
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Chemical exposure in flow-through sediment toxicity tests can vary in time, between pore and overlying water, and amid free and bound states, complicating the link between toxicity and observable concentrations such as free pore ( C free,pore ), free overlying ( C free,over ), or the corresponding dissolved concentrations ( C diss , free + bound to dissolved organic carbon, DOC). We introduce a numerical model that describes the desorption from sediments to pore water, diffusion through pores and the sediment-water boundary, DOC-mediated transport, and mixing in and outflow from overlying water. The model explained both the experimentally measured gap between C free,over and C free,pore and the continuous decrease in overlying C diss . Spatially resolved modeling suggested a steep concentration gradient present in the upper millimeter of the sediment due to slow chemical diffusion in sediment pores and fast outflux from the overlying water. In contrast to continuous decrease in overlying C diss expected for any chemical, C free,over of highly hydrophobic chemicals was kept relatively constant following desorption from DOC, a mechanism comparable to passive dosing. Our mechanistic analyses emphasize that exposure will depend on the chemical's hydrophobicity, the test organism habitat and uptake of bound chemicals, and the properties of sediment components, including DOC. The model can help to re-evaluate existing toxicity data, optimize experimental setups, and extrapolate laboratory toxicity data to field exposure.