不同起源秋茄林湿地沉积物重金属污染与健康风险评价

Heavy metal pollution and health assessment in sediments of Kandelia obovata wetlands of different origins

关键词:  重金属污染, 秋茄, 沉积物, 健康评价, 闽东湿地

Key words:  heavy metal pollution, Kandelia obovata, sediment, health assessment, wetland in East Fujian

摘要:

秋茄(Kandelia obovata)林生态系统的重金属污染是滨海湿地研究的重要组成。为探究闽东不同起源秋茄林湿地的健康风险与重金属污染的状况,运用污染负荷指数法和人体健康风险评价法分析闽东不同起源秋茄林湿地表层沉积物重金属的含量特征并评估其健康风险。结果表明:(1)秋茄天然林湿地表层沉积物重金属平均含量排序为Zn(102.38 mg·kg^-1)> Pb(101.53 mg·kg^-1)> Cu(11.72 mg·kg^-1)> Cd(0.91 mg·kg^-1); 秋茄人工林表层沉积物重金属含量排序为Zn(152.81 mg·kg^-1)> Pb(105.83 mg·kg^-1)> Cu(16.38 mg·kg^-1)> Cd(1.33 mg·kg^-1)。(2)天然红树林表层沉积物重金属的区域污染负荷指数(I_{PL zone})低于人工红树林,对应的污染等级均为1,属于中度污染。(3)秋茄林湿地表层沉积物重金属对成年男性和成年女性非致癌风险(RN)均低于1,对人体造成的非致癌风险很低,Pb元素对儿童的RN高于1,会对儿童造成非致癌风险; Cd对成年男性、成年女性和儿童的致癌风险(RI)均大于1.0×10^-6,对人体存在严重的致癌风险。综上所述,闽东秋茄林湿地重金属污染较为严重,应控制湿地周边污染物排放和对湿地进行净化治理。

Abstract:

Heavy metal pollution in Kandelia obovata ecosystem is an important part of coastal wetland research. In order to explore the health risk and heavy metal pollution of K. obovata wetland of different origins in eastern Fujian, this study explored the content characteristics of heavy metals in surface sediments of different origins of K. obovata wetlands and assessed their health risks in East Fujian by using the pollution load index method and human health risk assessment method. The results were as follows:(1)The average contents of heavy metals in surface sediments of K. obovata natural forest wetlands were Zn(102.38 mg·kg^-1)> Pb(101.53 mg·kg^-1)> Cu(11.72 mg·kg^-1)> Cd(0.91 mg·kg^-1). The order of heavy metal contents in surface sediments of K. obovata plantation was Zn(152.81 mg·kg^-1)> Pb(105.83 mg·kg^-1)> Cu(16.38 mg·kg^-1)> Cd(1.33 mg·kg^-1).(2)The regional pollution load index(I_{PL zone})of heavy metals in surface sediments of K. obovata natural forest was lower than that of K. obovata plantation, and the corresponding pollution levels of K. obovata plantation and natural forest were both one, which belonged to moderate pollution.(3)The non-carcer risk(RN)of heavy metals in surface sediments of K. obovata wetlands to adult males and adult females was lower than one, and the RN to human body was very low. The RN of Pb element to children was higher than one, it would cause RN to children. The carcer risk(cancer risk, RI)of Cd to adult males, adult females and children was greater than 1.0×10^-6, and there was a serious RT to the human body. The results indicate that heavy metal pollution of wetlands in East Fujian was serious. Therefore, we should control the pollutant emission around the wetland and purify the wetlands. In addition, adding the health risk assessment of heavy metals to the evaluation of K. obovata wetland ecosystem will help to strengthen the ecological protection and risk management of K. obovata.