Application of diffusive gradients in thin films (DGT) and simultaneously extracted metals (SEM) for evaluating bioavailability of metal contaminants in the sediments of Taihu Lake, China
Application of diffusive gradients in thin films (DGT) and simultaneously extracted metals (SEM) for evaluating bioavailability of metal contaminants in the sediments of Taihu Lake, China
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应用薄膜扩散梯度 (DGT) 和同步萃取金属 (SEM) 评估中国太湖沉积物中金属污染物的生物利用度
DOI：
10.1016/j.ecoenv.2019.109627
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发表时间：
2019
影响因子：
6.8
通讯作者：
Zhu Lingyan
中科院分区：
文献类型：
--
作者：
Zhang Yanfeng;Yang Jinxi;Simpson Stuart L.;Wang Yuanyuan;Zhu Lingyan
沉积物中重金属的毒性与其生物有效性有关，这对于制定可靠的沉积物质量基准至关重要。为了评价重金属（Cd、Cu、Ni、Pb和Zn）的生物有效性，采集了中国最大和最重要的淡水湖之一太湖沉积物。同时提取的金属（1-M盐酸提取，CSEM）在沉积物中，金属从沉积物中释放到孔隙沃茨和薄膜（DGT，CDGT）中的扩散梯度积累的浓度，和溶解的金属上覆水（COLW）分别进行了测量。沉积物的毒性进行了评估与tubificids（Monopylephorus limosus）和摇蚊（ChironomuskiiensisandChironomus tentans）。总金属含量与CSEM、CDGT和COWL测量值之间存在显著相关性（r2= 0.43- 0.95，n = 27，p< 0.001），与CSEM的相关性（r2= 0.91-0.95）强于CDGT（r2= 0.56-0.85）和COWL（r2= 0.43-0.71）。通过将CSEM除以沉积物质量基准值（SQGV）以及将CDGT和COWL除以水质标准（WQC）来获得风险因子。基于CSEM的风险商数比基于CDGT和COLW的风险商数更好地解释了沉积物对三种物种的毒性。该研究表明，在沉积物中面朝下部署的DGT活塞式探针所积累的金属与对这些淡水底栖生物造成毒性的生物可利用金属部分不成比例，而且对上覆沃茨中的金属进行单一测量不足以预测沉积物的毒性风险。CSEM的测量被确定为是有效的评估太湖沉积物中的金属所构成的风险，但提供了有限的改善，总金属浓度的测量。
The toxicities of heavy metals in sediments are related to their bioavailability, which is critical for deriving reliable sediment quality guidelines. To evaluate the bioavailability of the metals (Cd, Cu, Ni, Pb and Zn), sediments were collected from Taihu Lake, one of the largest and most important freshwater lakes in China. Concentrations of simultaneously extracted metals (1-M HCl extraction, CSEM) in the sediments, metals released from sediment to pore waters and accumulated by diffusive gradients in thin films (DGT, CDGT), and dissolved metals in the overlying water (COLW) were measured separately. Sediment toxicity was assessed with tubificids (Monopylephorus limosus) and chironomids (ChironomuskiiensisandChironomus tentans). Significant relationships existed between the total metal concentrations and CSEM, CDGT, and COLWmeasurements (r2= 0.43–0.95,n= 27,p< 0.001), with stronger relationships with CSEM(r2= 0.91–0.95) than CDGT(r2= 0.56–0.85) and COLW(r2= 0.43–0.71). Risk quotients were derived by dividing CSEMby sediment quality guideline values (SQGVs), and by dividing both CDGTand COLWby water quality criteria (WQC). Toxicity of the sediments to the three species was better explained by the CSEM-based risk quotient than those derived from CDGTand COLW. The study indicated that DGT piston probes deployed face down in sediments did not accumulate metals in proportion to the bioavailable metal fraction that caused toxicity to these freshwater benthic organisms, and that single measurements of metals in overlying waters are not adequate for predicting risks of toxicity from sediments. The measurement of CSEMwas determined to be effective for assessing the risk posed by the metals in the Taihu Lake sediments, but offered limited improvement over measurement of total metal concentrations.