广东红海湾表层沉积物重金属含量的空间分布特征与污染状况评价

Concentration Distribution and Pollution Assessment of Heavy Metals in Surface Sediments in Honghai Bay

对红海湾近岸海域20个采样站沉积物样品中的7种重金属含量分布进行了研究,结果表明:该海域表层沉积物中Cu、Pb、Zn、Cd、Cr、Hg和As质量分数范围分别为2.60~13.30、16.70~38.00、45.20~81.10、0.00~0.11、10.40~23.10、0.03~0.50、6.42~10.20 mg·kg^(-1),平均值分别为6.29、25.44、57.87、0.03、15.32、0.07、7.97 mg·kg^(-1),其中,Cu、Zn、Cd、Cr和Hg平均值低于全国海岸带重金属的背景值。海洋沉积物质量单因子污染指数法评价结果显示,Cu、Pb、Zn、Cd、Cr、Hg和As的平均含量均符合海洋沉积物质量Ⅰ类标准,7种重金属平均含量的污染程度为Pb>As>Zn>Hg>Cr>Cu>Cd。潜在生态危害指数法评价结果显示,红海湾近岸海域潜在生态风险指数等级"较低",海洋生态环境状况较好;结合重金属富集程度分析,该海域Pb的富集程度较高且集中于近岸海域。表层沉积物中重金属和TOC相关性分析表明:该海域表层沉积物TOC含量与重金属Cu、Pb、Zn、Cr和As含量具有一定的正相关性。进一步通过主成分分析研究沉积物中重金属污染来源,发现前2个主成分的贡献率分别为60.41%和16.48%;结合相关性分析,认为该海域沉积物重金属Cu、Pb、Zn、Cr和As的主要来源为工业废水与城市污水。文章揭示了红海湾近岸海域沉积物中重金属的分布特征,可为海洋生态环境建设提供依据。

Surface sediment samples at20sites in the offshore area of Honghai Bay were collected in May2015,to investigate thedistribution of7heavy metals(Cu,Pb,Zn,Cd,Cr,Hg and As)in that area.The results showed that mass fraction of Cu,Pb,Zn,Cd,Cr,Hg and As in the surface sediment varied in the range of2.60~13.30,16.70~38.00,45.20~81.10,0.00~0.11,10.40~23.10,0.03~0.50,6.42~10.20mg?kg-1,respectively.The average value was6.29,25.44,57.87,0.03,15.32,0.07,7.97mg?kg-1,respectively.The average valueof Cu,Zn,Cd,Cr and Hg were lower than the background values of the coastal zone of China.Marine sedimentquality was evaluated with the Single Factor Pollution Index method.The results showed that the average value of Cu,Pb,Zn,Cd,Cr,Hg and As conformed to the first-class standard of marine sediment quality.The Pollution Index values of7metals were in thefollowing order:Cd>Hg>Pb>As>Cu>Zn>Cr.The evaluation with the Potential Ecology Risk Index method showed that the indexgrade was relatively low.The marine ecological environment kept in good state.According to the analysis on accumulationcharacteristics of heavy metals,the concentrations of Pb were in high level in the offshore area.According to the PrincipalComponent Analysis of the heavy metals in the surface sediment,contributory ratio of the first and second principal component was60.41%and16.48%,respectively.Positive correlation was observed between concentrations of7heavy metals and TOC,respectively.Result of principal component analysis showed that the main sources of heavy metals Cu,Pb,Zn,Cr and As in marine sedimentswere industrial wastewater and urban sewage.This article revealed the distribution of the heavy metals in the offshore area ofHonghai Bay in order to provide scientific basis for marine sustainable development and marine ecological civilization construction.