辽东湾表层沉积物重金属生态风险及预警

为对辽东湾表层沉积物重金属的潜在生态风险进行定量评价及预警分析，根据2012—2015年每年8月的调查数据，计算了6种重金属元素（cu、PB、ZN、CD、HG和AS）的IGEO（地累积指数）、rI（综合潜在生态危害指）和IGE（生态风险预警指数）．　结果表明:2012年和2013年辽东湾表层沉积物重金属元素的IGEO由大到小顺序为AS>CU>ZN>PB>CD>HG，2014年为AS>CU>ZN>PB>CD>；2012—2014年辽东湾表层沉积物重金属污染区域主要位于北部河流入海口海域、葫芦岛周边海域．　风险分级和预警评价结果显示，各重金属元素的ＥＲＩ（单项潜在生态危害指数）平均值均小于40，rI均小于150，处于低潜在生态风险状态；辽东湾所有采样点中，2012年有5.6%的采样点处于2级生态风险等级（O　eR≤1.0），属生态风险预警级别，94.4%的采样点处在生态风险无警级别，2013—2014年所有采样点均处于生态风险无警级别．　对辽东湾生态环境具有潜在危害的元素是CD、aS和HG，辽东湾表层沉积物中AS、ZN、CD在部分采样点已达到生态风险预警级别，应加大对该海域的环境监测力度． 

Ecological Risk Assessment and Early Warning of Heavy Metals in the Surface Sediments of Liaodong Bay

Ecological risk assessment and early warning of surface sediments in Liaodong Bay were conducted by a geoaccumulation index (Igeo), a potential ecological risk index (RI) and an ecological risk warning model (IER) based on the concentrations of a range of heavy metals (As, Cd, Cu, Hg, Pb and Zn) from August 2012 to August 2014. The Igeo results showed that the regional sediments were practically uncontaminated (Igeo<0). The sequence of different elements' Igeo was As>Cu>Zn>Pb>Cd>Hg in both 2012 and 2013, while it changed to As>Zn>Cu>Pb>Hg>Cd in 2014. The contaminated areas were mainly distributed in the northern estuaries of Liaodong Bay and near Huludao. The average potential ecological risk indexes for single heavy metals (Eri) were less than 40, and the potential toxicity response index (RI) from 2012 to 2014 was less than 150, which was in the low risk category. Approximately 5.6% of the sampling sites were classified in the second ecological risk level （O　eR≤1.0） in 2012, which indicated an ecological risk warning, while the remaining 94.4% were in the “no ecological risk warning” category. No ecological risks were documented in 2013 and 2014. The RI calculations indicate that there are potential ecological risks from As, Cd and Hg in Liaodong Bay. The numerical values from IER calculations for surface sediments of Liaodong Bay show that there will most likely be negative impacts on the environment from As, Cd and Zn.