洞庭湖东南缘草鱼、鲢鱼及其生活水域底泥微量元素含量特征及健康风险评价

Grass Carp,Silver Carp and Their Living Waters Sediment Trace Elements Content Characteristics and Health Risk Assessment in the southeast edge of Dongting Lake

为研究洞庭湖东南缘日常消费鱼类(草鱼、鲢鱼)及其生活水域底泥微量元素的含量特征及健康风险水平,采集了洞庭湖东南缘不同水域13件表层水、57件表层底泥、29件草鱼、35件鲢鱼样品,采用污染指数法、潜在生态风险评价法分别评估了表层水中重金属的污染水平和底泥中重金属的污染特征;利用目标系数危害法分别计算了草鱼、鲢鱼对两类人群(成人和儿童)的非致癌健康风险。研究结果表明,洞庭湖东南缘主要养殖水域除Hg元素为国家Ⅲ类地表水标准,其他元素都在国家Ⅰ类地表水限值内,Hg、Pb、Zn、Cu、Se超过环境背景值,分别是洞庭湖背景值的2.2、1.8、2.4、2、1.8倍。洞庭湖东南缘水域底泥平均RI(生态危害指数)为166.7,属于中度潜在生态风险水平,主要是湘江点位和洞庭湖口点位RI较高。两种鱼类全部达到富硒标准,其中草鱼有4件,鲢鱼有10件超出富硒食品含量标准,鲢鱼有13件样品As超出无公害水产限值标准,草鱼、鲢鱼安全富硒率分别为86%和34%,综合污染指数鲢鱼大于草鱼,表现出不同习性鱼类对重金属富集能力为杂食性>食草性。目标系数危害法评价结果表明,两种鱼类THQ(单一重金属风险)、TTHQ(多种重金属复合风险)对于成人和儿童均小于1,对人群健康风险不明显。鱼类重金属污染水平与水域呈极显著正相关,相关系数为0.957,与底泥相关性不显著。本文研究结果表明洞庭湖东南缘草鱼、鲢鱼全部富硒,且食用安全性良好,主要污染来源是As,需要从饲料、水源环境做好防范。

In order to study the content characteristics and health risk level of trace elements of daily consumption fish(grass carp,silver carp)and their living waters sediment in the southeast edge of Dongting Lake,13 surface water,57 surface sediment,29 grass carp and 35 silver carp samples from different waters in the southeast edge of Dongting Lake were collected.The surface water pollution level and the sediment heavy metal pollution feature were evaluated respectively through pollution index and potential ecological risk assessment,and the non-carcinogenic health risk of grass carp and silver carp on adults and children was calculated by target coefficient hazard.The research results show that except the Hg element content in the southeast edge of Dongting Lake aquiculture area is up to the national surface water standard,and the other elements are within the national class I surface water limits.Hg,Pb,Zn,Cu and Se contents exceed the environmental background values,which are 2.2,2.8,2.4,2 and 1.8 times of the background values of Dongting Lake,respectively.The average RI(ecological hazard index)of sediment in the southeast edge of Dongting Lake is 166.7,which is a moderate potential ecological risk level,mainly due to the high RI of Xiangjiang River and Dongting Lake mouth.Trace elements contens of the two kinds of fish are all up to selenium-rich standard,including 4 grass carp,10 silver carp samples beyond selenium-rich food content standard and 13silver carp samples beyond pollution-free aquatic product limit standard.Grass carp,silver carp safety selenium-rich rate are 86%and 34%respectively,while comprehensive pollution index of silver carp is greater than that of grass carp,showing differen heavy metal enrichment ability of omnivorous fish is stronger than that of herbivore fish.The evaluation results of the target coefficient hazard method show that the THQ(single heavy metal risk)and TTHQ(multiple heavy metal compound risk)of the two fish species are less than 1for adults and children,which means the health risk for the population is not obvious.The level of heavy metal pollution in fish is significantly and positively correlated with the water area,with a correlation coefficient of 0.957 and no significant correlation with the sediment.The research results of this paper show that all grass carp and silver carp in the southeast edge of Dongting Lake are rich in selenium,and they are well safe to eat.The main source of pollution is As,which needs to be prevented from the feed and water environment.