红碱淖沉积物重金属分布特征及生态风险评价

Distribution Features and Ecological Risk Evaluation of Heavy Metal in the Sediment of Hongjiannao Lake

为了清楚陕北红碱淖湖泊沉积物重金属污染状况,2020年6月采集沉积物表层样品5个,柱状样品2个,分析沉积物重金属表层及垂向分布特征,并利用地累积指数法和潜在生态风险指数法进行评价。结果表明:红碱淖表层沉积物重金属Hg、As、Cu、Cd含量变化范围分别为0.042~0.058mg/kg、1.40~5.09mg/kg、2.00~4.00mg/kg、0.13~0.20mg/kg,呈现湖心区>湖周区的分布规律。柱状沉积物HJ3点位Hg、As、Cu、Cd含量变化范围分别为0.04~0.06mg/kg、1.95~3.75mg/kg、2.00~6.00mg/kg、0.15~0.26mg/kg,柱状沉积物HJ5点位,Hg、As、Cu、Cd含量变化范围分别为0.038~0.044mg/kg、1.40~1.75mg/kg、2.00~4.00mg/kg、0.13~0.24mg/kg,As、Cu和Cd垂向变化规律基本一致,呈现随着深度增加先增大后减小的变化规律。重金属Cd处于轻度污染水平,各重金属元素均有中等生态危害。

In order to probe heavy-metal pollution status of the sediment of Hongjiannao Lake in northern Shaanxi,in June 2020,5 surface samples and 2 column samples in the sediment were collected to analyze surface and vertical distribution features of heavy metal as the Geoaccumula-tion Index and the potential ecological risk index were employed for evaluation.The results show that the content change range of heavy metals Hg,As,Cu,and Cd are 0.042~0.058 mg/kg,1.40~5.09 mg/kg,2.00~4.00 mg/kg,0.13~0.20 mg/kg,respectively,featuring central lake>peripheral lake.For column sediment HJ3 spot,the content change range of Hg,As,Cu,and Cd are 0.04~0.06 mg/kg,1.95~3.75 mg/kg,2.00~6.00 mg/kg,0.15~0.26 mg/kg,respectively.For column sediment HJ5 spot,the content change range of Hg,As,Cu,and Cd are 0.038~0.044 mg/kg,1.40~1.75 mg/kg,2.00~4.00 mg/kg,0.13~0.24 mg/kg,respectively.As,Cu,and Cd display consistent vertical change that increased before reduced as the depth in-creased.Heavy metal Cd is at the level of mild pollution.These heavy metal elements pose a medium ecological risk.