摘要
为了解近年来洞庭湖表层沉积物中氮、磷及重金属污染情况,对洞庭湖15个采样点表层沉积物中TN、TP和重金属(Cu、Zn、Pb、Cd、Ni、Cr、Hg、As)质量分数进行分析,并运用有机指数和综合营养法对TN、TP的污染程度进行评价,采用重金属潜在生态风险指数法、综合地积累指数法对重金属进行生态风险评价,利用主成分分析重金属的来源。结果表明,洞庭湖表层沉积物中w(TN)和w(TP)的范围分别介于576—1526 mg·kg^(−1),482—982 mg·kg^(−1)之间。空间分布上,TN和TP总体均表现为东洞庭湖>南洞庭湖>西洞庭湖。洞庭湖表层沉积物中重金属含量在0.08—378.5 mg·kg^(−1)之间,Cu、Ni呈现东洞庭湖>南洞庭湖>西洞庭湖,Cd、Hg、Pb、As呈现南洞庭湖>东洞庭湖>西洞庭湖,Cr呈现东洞庭湖>西洞庭湖>南洞庭湖,Zn呈现南洞庭湖>西洞庭湖>东洞庭湖。洞庭湖表层沉积物中有机氮Ⅳ级污染点位约占所有点位的20%,有机氮Ⅲ级污染点位占比约为73.3%。营养盐综合污染指数等级为中度污染,空间分布整体呈现为东洞庭湖>南洞庭湖>西洞庭湖。洞庭湖表层沉积物中重金属风险RI值为483,潜在重金属生态风险为重污染,潜在重金属生态风险等级空间整体呈现为南洞庭湖>西洞庭湖>东洞庭湖。地积累指数表明洞庭湖表层沉积物重金属总体呈现偏重污染,空间分布为南洞庭湖>东洞庭湖>西洞庭湖。研究表明,洞庭湖表层沉积物营养盐综合污染呈现中等污染,重金属污染呈现重污染状态,Cd、Hg两种重金属的风险最高,洞庭湖表层沉积物重金属生态风险主要是这两种重金属造成的。
To study the pollution status of nitrogen,phosphorus and heavy metals in surface sediment of Dongting Lake,the contents of total nitrogen(TN),total phosphorus(TP)and heavy metals(including Cu,Zn,Pb,Cd,Ni,Cr,Hg and As)in sediment of 15 sample sites in Dongting Lake were analyzed.Comprehensive pollution index(FF)and organic index were selected to evaluate pollution grade of TN and TP.Potential ecological risk index(RI)and comprehensive geoaccumulation index(Itot)were employed to assess health risk of heavy metal pollution.The source of heavy metals was analyzed by Principal component analysis(PCA).The results indicated that the contents of TN and TP ranged from 576 mg·kg^(−1) to 1526 mg·kg^(−1) and 482 mg·kg^(−1) to 982 mg·kg^(−1),respectively.The spatial distributions of TN and TP presented similar patterns in the order of East Dongting Lake>South Dongting Lake>West Dongting Lake.The contents of heavy metals in sediments of Dongting Lake ranged from 0.08 mg·kg^(−1) to 378.5 mg·kg^(−1).Spatially,the contents of Cu and Ni ranked as an order:East Dongting Lake>South Dongting Lake>West Dongting Lake.The contents of Cd,Hg,Pb and As showed similar spatial trend,they all decreased in the order of South Dongting Lake>East Dongting Lake>West Dongting Lake.The content of Cr was ranked as an order as follow:East Dongting Lake>West Dongting Lake>South Dongting Lake.The content of Zn ranked as an order:South Dongting Lake>West Dongting Lake>East Dongting Lake.The results of organic index indicated that sampling sites evaluated as organic nitrogenⅣlevel accounted for 20%,and sites of organic nitrogenⅢlevel accounted for 73.3%.Comprehensive pollution index indicated moderate pollution,and the pollution level of spatial distribution ranked as an order:East Dongting Lake>South Dongting Lake>West Dongting Lake.The result of RI of Dongting Lake was 483,indicated that potential ecological risk level of Dongting Lake was heavy,and RI values decreased in the order of South Dongting Lake>west Dongting Lake>East Dongting Lake.The results of Itot indicated that contamination of heavy metals in sediments of Dongting Lake was serious,and Itot value decreased in the order of South Dongting Lake>East Dongting Lake>West Dongting Lake.The research showed that comprehensive nutrient pollution in surface sediment of Dongting Lake was moderate,and metals pollution in surface sediment of Dongting Lake was serious.Hg and Cd were the highest risk elements,and the ecological risk of heavy metals in surface sediments of Dongting Lake was mainly caused by these two kinds of heavy metals.
作者
尹宇莹
彭高卓
谢意南
莫永涛
李芬芳
欧阳美凤
黄代中
YIN Yuying;PENG Gaozhuo;XIE Yinan;MO Yongtao;LI Fenfang;OUYANG Meifeng;HUANG Daizhong(Ecological and Environmental Monitoring Central of Dongting Lake of Hunan,Yueyang,414000,China)
出处
《环境化学》
CAS
CSCD
北大核心
2021年第8期2399-2409,共11页
Environmental Chemistry
基金
国务院三峡工程建设委员会办公室/江湖生态监测重点站(洞庭湖)项目(JJ2017-028)资助.
关键词
洞庭湖
表层沉积物
总氮
总磷
重金属
风险评价
Dongting Lake
surface sediment
total nitrogen
total phosphorus
heavy metals
risk assessment
