Novel Passive Sampling Device for Measuring Sediment鈥揥ater Diffusion Fluxes of Hydrophobic Organic Chemicals

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• 作者：Hui-Hui Liu ; Lian-Jun Bao ; Kai Zhang ; Shi-Ping Xu ; Feng-Chang Wu ; Eddy Y. Zeng
• 刊名：Environmental Science & Technology
• 出版年：2013
• 出版时间：September 3, 2013
• 年：2013
• 卷：47
• 期：17
• 页码：9866-9873
• 全文大小：409K
• 年卷期：v.47,no.17(September 3, 2013)
• ISSN：1520-5851

文摘

Molecular diffusion across the sediment鈥搘ater interface, as one of the key geochemical processes, dictates whether a sediment is a source or sink of chemicals, providing useful data in designing remedial actions. Despite ample previous efforts in quantifying sediment鈥搘ater diffusion fluxes, the resulting methods are largely unsatisfactory. Herein, we introduce a novel passive sampling device capable of measuring vertical profiles of chemical concentrations near the sediment鈥搘ater interface, from which diffusion fluxes can be calculated based on a model that we developed. In laboratory testing, diffusion fluxes (0.032鈥?10 ng m^鈥? d^鈥?) of dichlorodiphenyltrichloroethane and its metabolites obtained from the present sampling device were consistent with those (0.38鈥?10 ng m^鈥? d^鈥?) determined by using a conventional active sampling method, solid-phase extraction/liquid鈥搇iquid extraction. Field deployment of the sampling device yielded individual diffusion fluxes of p,p鈥?DDD, p,p鈥?DDE, p,p鈥?DDMU, o,p鈥?DDMU, p,p鈥?DDNU, and p,p鈥?DBP in the range of 5.9鈥?50 ng m^鈥? d^鈥?, which were comparable to those (5.5鈥?5 ng m^鈥? d^鈥?) obtained with a benthic chamber. Moreover, diffusion fluxes of p,p鈥?DDT and o,p鈥?DDT obtained with the sampling device were negative; i.e., the sediment is acting as a sink for these chemicals, while that could not be found using the benthic chamber. Thus, the passive sampling device can provide better information about the movement of chemicals through the sediment and overlying water for the choice of remedial strategies.