| 引用本文: | 刘成,黄蔚,古小治,张雷,陈开宁.白洋淀沉积物重金属潜在生态风险及生物可利用性分析.湖泊科学,2022,34(6):1980-1992. DOI:10.18307/2022.0614 |
| Liu Cheng,Huang Wei,Gu Xiaozhi,Zhang Lei,Chen Kaining.The potential ecological risks and bioavailability of heavy metals in the sediments of Lake Baiyangdian. J. Lake Sci.2022,34(6):1980-1992. DOI:10.18307/2022.0614 |
|
| 摘要: |
| 沉积物是湖泊水体重金属的主要汇集场所，也是湖泊重金属污染研究及整治的重点.本文分析了白洋淀多个淀区沉积物中16种重金属含量水平及垂向分布特征，解析了其中典型有害重金属潜在生态风险，并基于酸可挥发性硫（AVS）及同步可提取金属（SEM）、间隙水溶解态金属、可转化态金属形态分级等研究，对重金属生物可利用性进行了分析.结果表明：沉积物重金属含量均值高低依次为Fe （29630.50 mg/kg）>Ti （3213.07 mg/kg）>Mn （539.44 mg/kg）>Zn （104.01 mg/kg）>V （76.63 mg/kg）>Cr （52.60 mg/kg）>Cu （43.49 mg/kg）>Ni （35.83 mg/kg）>Pb （26.75 mg/kg）>Co （10.32 mg/kg）>As （8.96 mg/kg）>Mo （2.06 mg/kg）>Sb （1.57 mg/kg）>Tl （0.43 mg/kg）>Cd （0.31 mg/kg）>Hg （0.16 mg/kg）；其中，10种重金属在各淀区沉积物中呈现出自北往南逐渐降低的趋势，各金属在不同淀区分布差异性主要由污染输入所致.除北部烧车淀区域外，其余区域重金属潜在生态风险总体处于较低水平.重金属污染主要来源于该区域周边河道，但近10年来污染输入及在沉积物中的富集总体趋于稳定并呈逐渐降低的趋势.入淀污染不仅增加了该区域沉积物中重金属总量，也使得其中可转化态重金属比例较高，大多在30%~90%之间，提升了重金属生物可利用潜力.水生植物等内生性有机质的大量富集导致沉积物还原性较强，AVS含量较高，沉积物中AVS和ΣSEM均值分别为（10.59±6.37）和（2.23±1.53）μmol/g （dw）.Cd、Cu、Ni、Pb、Zn等金属由于高含量还原态硫的固定而生物可利用性较低.然而，As和Hg在这样的高有机质和强还原环境下更容易溶解和释放，是潜在生物可利用性相对较高的金属，在间隙水中的浓度分别达到（17.07±0.23）和（2.39±0.94）μg/L，未来研究及整治中应给予更多关注. |
| 关键词: 白洋淀 重金属形态 间隙水 生物可利用性 酸可挥发性硫 同步可提取金属 |
| DOI：10.18307/2022.0614 |
| 分类号: |
| 基金项目:国家自然科学基金项目（42077310）、江苏省科协青年科技人才托举工程（2020）和云南省环境治理项目（QT[2020]THXQ09）联合资助. |
|
| The potential ecological risks and bioavailability of heavy metals in the sediments of Lake Baiyangdian |
|
Liu Cheng1, Huang Wei1, Gu Xiaozhi1, Zhang Lei1, Chen Kaining1,2
|
|
1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, P. R. China
|
| Abstract: |
| Being the primary sink for heavy metals in lakes, the sediment is the hotspot for the research and remediation of heavy metals in lakes. In the current study, the horizontal and vertical distributions of 16 kinds of heavy metals in the sediment of multiple areas in Lake Baiyangdian were analyzed and based on the concentrations of several typical harmful heavy metals in the sediment, the potential ecological risk was assessed. The bioavailability of heavy metals was further analyzed according to the acid volatile sulfide (AVS), simultaneously extracted metals (SEM), dissolved metals in the pore water, and fractionation of mobile metals. The results showed that the concentrations of heavy metals in the sediment followed the descending order of:Fe (29630.50 mg/kg)>Ti (3213.07 mg/kg)>Mn (539.44 mg/kg)>Zn (104.01 mg/kg)>V (76.63 mg/kg)>Cr (52.60 mg/kg)>Cu (43.49 mg/kg)>Ni (35.83 mg/kg)>Pb (26.75 mg/kg)>Co (10.32 mg/kg)>As (8.96 mg/kg)>Mo (2.06 mg/kg)>Sb (1.57 mg/kg) >Tl (0.43 mg/kg)>Cd (0.31 mg/kg)>Hg (0.16 mg/kg). Among all the heavy metals studied, 10 kinds of the metals in the sediment of the studied areas showed a gradually decreasing trend from north to south of the lake. The variations in the horizontal distribution of metals between different areas were most likely caused by the external pollution input from the north part of the lake. The potential ecological risks of heavy metals in most parts of the lake were generally at low levels except for the Shaochedian area in the north. The inflowing rivers around this area were the main sources of heavy metal pollution. While the pollution input and the accumulation of heavy metals in the sediment have generally stabilized and gradually decreased during the past 10 years, the pollution input not only increased the total amount of heavy metals in the sediment of this area but also led to the high proportion of mobile heavy metals (mostly between 30% and 90%), which increased the bioavailable potential of metals. The massive enrichment of endogenous organic matter from the wither of aquatic plants led to the strong reductive status of the sediment, which thereby resulted in high concentrations of AVS. The average concentrations of AVS and ΣSEM in the sediment of the whole lake were (10.59±6.37) μmol/g(dw) and (2.23±1.53) μmol/g(dw), respectively. Due to the immobilization with a high concentration of sulfides, the bioavailability of Cd, Cu, Ni, Pb, and Zn were generally low. However, As and Hg are much easier to dissolve and release from the sediment under such high organic matter content and strong reducing environment. These two metals had relatively high potential bioavailability with the concentration in the pore water reaching (17.07±0.23)μg/L and (2.39±0.94)μg/L, respectively, which should be given more attention during future research and remediation works. |
| Key words: Lake Baiyangdian heavy metal fractions pore water bioavailability acid volatile sulfide simultaneously extracted metals |
