闽江口表层沉积物中重金属含量分布特征及其潜在生态风险评价

对闽江口11个采样点的表层沉积物中重金属含量进行测定,结果显示各重金属含量分别为Cu4.8～34.3mg/kg(平均20.4mg/kg)、Pb12.4～28.9mg/kg(平均20.0mg/kg)、Cd0.064～0.393mg/kg(平均0.13mg/kg)、Hg0.01～0.2mg/kg(平均0.08mg/kg)、As3.8～12.5mg/kg(平均9.3mg/kg)。全部站位的重金属含量均符合国家海洋沉积物质量第一类标准,主要污染物是Cu、As和Hg。Cu、Pb含量空间分布特征相似;Cd、Hg、As含量空间分布特征不同;各元素含量均随着离岸距离的增大有递减的趋势。潜在生态风险评价结果表明,闽江口水域总体为轻微生态风险,重金属污染的风险系数较小,该水域重金属元素的污染风险系数大小顺序为:HgAsCdPbCu。

Distribution and potential ecological risk assessment of heavy metals in surface sediments of Minjiang Estuary

The concentrations of heavy metals in the 11 surface sediments sampled from Minjiang Estuary were determined.The results indicated that the concentration range（average） of Cu,Pb,Cd,Hg and As were 4.8～34.3mg/kg（20.4mg/kg）,12.4～28.9mg/kg（20.0mg/kg）,0.064～0.393mg/kg（0.13mg/kg）,0.01～0.2mg/kg（0.08mg/kg）and 3.8～12.5mg/kg（9.3mg/kg） respectively.The concentrations of heavy metals in every station were up to the classⅠstandard of marine sediment quality.The concentration space distributions of Cu and Pb were similar.The space distributions of Cd、Hg、As concentration were different.The concentrations of every heavy metal appear gradually degressive from west to east in Minjiang Estuary.The potential ecological risk index indicated that Minjiang Estuary belonged to low ecological risk,and the pollution of heavy metals was not very obvious in this period.The sequence of pollution risk for the heavy metals in Minjiang Estuary was： HgAsCdPbCu.