Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland 21227, United States.
Environ Sci Technol. 2022 Jul 19;56(14):10020-10029. doi: 10.1021/acs.est.2c00312. Epub 2022 Jun 27.
The freely dissolved concentration of hydrophobic pollutants in sediment porewater () is a critical driver for exposure to aquatic organisms, bioaccumulation, toxicity, and flux across interfaces. In this research, we compared direct porewater extraction and passive sampling for measurements of a range of PCBs and PAHs in field-collected sediments. The direct water extraction method provided accurate quantification of for low to moderately hydrophobic PCB and PAH compounds (log < 6.5) that compared well with independent measurements performed using four passive sampling methods. Direct water extraction was adequate to assess narcosis toxicity of PAHs to benthic organisms that is driven by the concentrations of low to moderately hydrophobic PAHs (naphthalene to chrysene), even for a hypothetical sediment that had a tenth of the PAH concentrations of the study sediments and was assessed to be nontoxic. Prediction of PCB bioaccumulation in benthic organisms agreed within 50% for all measurement methods, but it was apparent that for less contaminated sediments, the direct water extraction method would likely have detection limit challenges, especially for the strongly hydrophobic PCBs. To address the uncertainty of the measurement of the strongly hydrophobic compounds and naphthalene, a new extrapolation approach is demonstrated that can be applicable for both direct water extraction and passive sampling methods.
疏水性污染物在沉积物孔隙水中的自由溶解浓度（）是影响水生生物暴露、生物累积、毒性和界面通量的关键因素。本研究比较了直接孔隙水提取法和被动采样法在现场采集沉积物中测量一系列 PCB 和 PAH 的应用。直接水样提取法可准确量化低到中等疏水性 PCB 和 PAH 化合物（log < 6.5）的，与使用四种被动采样方法进行的独立测量结果相当。直接水样提取法足以评估低到中等疏水性 PAH（萘到苊烯）对底栖生物的麻醉毒性，即使对于假设的沉积物，其 PAH 浓度仅为研究沉积物的十分之一且被评估为无毒性。对于所有测量方法，PCB 在底栖生物中的生物累积预测都在 50%以内，但显然对于污染程度较低的沉积物，直接水样提取法可能存在检测极限挑战，尤其是对于强疏水性 PCB。为了解决强疏水性化合物和萘的测量不确定性，提出了一种新的外推方法，该方法可适用于直接水样提取法和被动采样法。
