连云港南海域沉积物重金属分布及其潜在生态风险评价

Distribution pattern and the potential ecological risk evaluation of heavy metals in the sediments in Lianyungang south sea areas

根据2013年3月份和10月份连云港南海域11个站位沉积物重金属(Cu,Zn,Pb,As,Cd,Hg)的调查数据,重点分析了重金属含量时空分布特征,采用Hakanson潜在生态风险指数法对重金属潜在生态风险性进行评价.结果表明:从空间分布来看,3月份6种重金属含量空间分布总体趋势均为河口区>倾倒区>养殖区,10月份Cu,Zn,Pb,As的分布规律一致,即倾倒区>河口区>养殖区,倾倒区Cu,Zn,Pb,As,Cd 5种重金属分布均有由倾倒区中心向外含量逐渐降低的规律,说明倾倒的疏浚物是该海区重金属污染的重要来源;从时间上看,多数站位重金属含量3月份数值高于10月份;调查区内重金属的潜在生态风险指数均小于40,表明该海域表层沉积物重金属对海洋生态系统的潜在危害风险低;3月份各重金属对该海域潜在生态危害顺序为Hg>Cd>As>Cu>Pb>Zn,10月份为Hg>As>Cd>Cu>Pb>Zn;养殖区重金属生态风险指数均较低,这对该区海水养殖提供了重要参考.

The monitoring data o{ heavy metals （Cu, Zn, Pb, As, Cd, Hg） in sediments at 11 sites in Li- anyungang south sea areas were obtained in March and October, 2013 respectively. Based on that, the spa- tial and temporal distribution pattern of heavy metals was analyzed. Finally evaluation on the potential eco- logical risk of heavy metals was made using Hakanson potential ecological risk index. The results showedthat the spatial distribution of these six heavy metals decreased gradually as the estuary 〉 dumping area〉mariculture area in March, 2013. In October Cu, Zn, Pb, As shared the same distribution pattern, as they decreased gradually as dumping area〉the estuary 〉 maricuhure area. Except for Hg, the concentration of the other five heavy metals dropped gradually from the central dumping area to the surrounding area, which further proved that the dredged material constituted the major source of heavy metals within this sea area. By contrast the content of heavy metals in March was higher than that of October at most sites. Within the survey area the potential ecological risk indexes of heavy metals were unanimously smaller than 40, indicating the lower potential risk to the marine ecosystems from heavy metals in surface sediments. In March the potential ecological risk of these heavy metals to the sea areas was as follows： Hg〉 Cd〉As〉Cu〉Pb〉Zn, and in October the ecological risk followed the rule as Hg 〉 As 〉 Cd 〉 Cu 〉 Pb 〉 Zn. The ecological risk indexes within the maricuhure area were all low, which could serve as an important ref- erence for the future maricuhural development within this area.