升金湖重金属污染历史、来源解析及其生态风险评价

Pollution History of the Heavy Metal,Source Analysis and Its Ecological Risk Recorded in Lake Shengjin

通过采集、测定升金湖沉积岩芯重金属含量,基于岩芯AMS14C年代—深度模型,分析了升金湖1000 A.D.以来的重金属污染历史特征和可能来源,采用潜在生态风险指数法与富集系数法评价了升金湖流域不同历史时期生态风险。研究结果表明,元素As、Mn、Pb、Cu、Zn、Cr、V和Ni的平均含量分别为19.2、623.7、28.6、42.4、115.7、83.7、153.1和46.5 mg·kg^(-1)。随时间推移,升金湖沉积物中重金属综合潜在生态风险(RI)逐渐上升;1600 A.D.前元素As的潜在生态风险属于轻微生态危害,1900 A.D.后上升为中等生态危害,元素Cu、Mn、Ni、Pb、Zn、V和Cr均为轻微生态危害;各元素潜在生态危害由大到小排序为As>Cu>Ni>V>Pb>Cr>Mn>Zn, As、Cu为主要贡献因子。1600 A.D.前元素As为轻度富集,人为污染小,1600 A.D.后呈中等偏强富集,人为来源占比显著增加;1600 A.D.前元素Cu波动变化,1600 A.D.后呈中等富集,人为来源占比增加;其余重金属Mn、Pb、Ni、Cr、Zn、V富集程度较小,1900 A.D.后存在一定程度的人为来源。多元统计分析结果显示,1600 A.D.前重金属主要为自然状态下沉积,1600~1900 A.D.为人类活动与自然沉积共同作用,1900 A.D.后人类活动是重金属污染的主要来源,其中工业污染物排放、矿业开采、农业活动是重金属污染来源的主要影响因子。基于以上研究,分析了升金湖流域未来可能存在的生态风险,为长江下游流域生态环境保护与可持续发展提供了有益参考。

In order to explore the historical variation and potential ecological risk of heavy metal pollution of lake Shengjin in the lower reaches of the Yangtze River,a sediment core was drilled and analyzed from the sediments.Based on AMS14C dating results,the historical distribution characteristics and main sources of heavy metal pollution in the lower reaches of the Yangtze River during the past millennium were analyzed by using the enrichment coefficient and potential ecological risk index method combined.the results show that the mean contents of As,Mn,Pb,Cu,Zn,Cr,V and Ni are 19.2,623.7,28.6,42.4,115.7,83.7,153.1 and 46.5 mg/kg respectively.The comprehensive potential ecological risk(RI)of heavy metals in the sediments of Lake Shengjin gradually increased over time.The potential ecological risk of element As before 1600 A.D.is a slight ecological hazard,after 1900 A.D.,which rises to medium ecological hazard,and the elements Cu,Mn,Ni,Pb,Zn,V and Cr are all slight ecological hazards.The order of potential ecological risk of elements is As>Cu>Ni>V>Pb>Cr>Mn>Zn,As and Cu are the main contributing factors.before 1600 A.D.,the element As was slightly enriched and the anthropogenic pollution was small.After 1600 A.D.,which was moderately enriched and the proportion of anthropogenic sources increased significantly.Before 1600 A.D.,the element Cu fluctuated,and after 1600 A.D.,the stable variation range was moderately enriched.The remaining heavy metals Mn,Pb,Ni,Cr,Zn,V enrichment degree is small,after 1900 A.D.,there is a certain degree of anthropogenic sources.The results of multivariate statistical analysis showed that the heavy metals before 1600 A.D.,were mainly deposited in the natural state,1600-1900 A.D.,were the combined effects of human activities and natural deposition,and human activities after 1900 A.D.,were the main sources of heavy metal pollution.Among them,industrial pollutant emissions,mining and agricultural activities are the main influencing factors of heavy metal pollution sources.Based on the above findings,the possible ecological risks of Lake Shengjin basin in the future were analyzed,which provided a useful reference for the ecological environment protection and sustainable development of the lake basin in the lower reaches of the Yangtze River.