深圳湾沉积物重金属污染时空分布特征

根据1992~2013年间深圳湾沉积物的监测数据，重点分析了重金属砷（As）、镉（Cd）、铬（Cr）、铜（Cu）、铅（Pb）、汞（Hg）和锌（Zn）含量、来源、相关性、污染程度和生态风险等污染状况。深圳湾沉积物中重金属含量存在明显的时空分布特征。1992~2013年间，深圳湾尤其是近岸海域，沉积物重金属含量的基本变化趋势为先增加后下降，重金属含量在2000~2009年间相对较高；Cd、Cr、Cu、Pb、Hg和Zn的含量从湾内到湾口逐渐降低。重金属Cu、Pb、Zn和As的富集因子指数较高，说明这4种重金属主要来自人类活动。Cd、Cr、Cu、Pb和Zn之间存在明显的相关性，具有相似污染途径和迁移过程。深圳湾底泥中重金属Pb、Zn和Cu属于轻微污染程度，其他重金属为无污染程度。深圳湾沉积物重金属的生态危害程度为轻微生态风险，重金属中Hg的生态风险指数最高，As和Cd次之。

Spatial and temporal distribution of heavy metals in the sediment of Shenzhen bay

Based on the data collected from 1992 to 2013 in Shenzhen bay, the content, source, relationship, pollution degree and potential ecological risk of seven heavy metals (As, Cd, Cr, Cu, Pb, Hg and Zn) were analyzed.The temporal and spatial distribution of heavy metals in Shenzhen bay were different.During the period of 1992~2013, the contents of heavy metals especially in the inner bay areas increased initially and then decreased, and the contents were much higher in 2000~2009.In addition, the contents of Cd, Cr, Cu, Pb, Hg and Zn decreased from the inner bay to the open sea.The enrichment factors of Cu, Pb, Zn and As were higher than other heavy metals, and Cu, Pb, Zn and As were mainly contributed from human activities.The correlation of Cd, Cr, Cu, Pb and Zn was significant, indicating similar pollution sources and migration processes.Pb, Zn and Cu were within the slightly polluted degree, while As, Cd, Cr and Hg were belong to the non-polluted degree.The potential ecological risk of heavy metals in the sediment of Shenzhen bay was also very low, with the highest potentially ecological risk of Hg and followed by As and Cd.