广西海域沉积物重金属、滴滴涕、多氯联苯含量及生态风险分析

Assessment on the Pollution and Potential Ecological Risk of Heavy Metals, DDTs and PCBs in Sediments at Guangxi Sea Area

在广西近岸海域采集了36个站位的表层沉积物样品,测定了沉积物样品中Cu、Pb、Cd、Zn、Cr、Hg、As共7种重金属和DDTs、PCBs共2种持久性有机污染物的含量,分析了各检测因子的含量和分布特征,对沉积物中7种重金属和DDTs、PCBs进行了综合生态风险评价。结果表明:广西海域沉积物中重金属平均含量(×10-6,干重)顺序为Zn(49.4)>Cr(41.7)> Cu(21.5)>Pb(15.6)>As(9.1)>Cd(0.07)>Hg(0.026),持久性有机污染物平均含量(×10-9,干重)为PCBs(2.97)> DDTs(0.88),重金属、DDTs、PCBs所有站位含量平均值均低于一类标准,广西海域沉积物Cu、Pb、Cd、Zn、Cr、Hg、As、DDTs、PCBs总体含量水平较低;沉积物重金属潜在生态风险程度排序为Hg>As>Cd>Cu>Pb>Cr>Zn,36个监测站位的潜在生态风险指数RI平均值为19.51,广西海域总体潜在风险程度较轻,属低潜在生态风险,位于茅尾海和廉州湾的站位潜在生态风险较高,As和Cu为主要的潜在生态风险因子;沉积物中DDTs、PCBs的残留水平生态风险较低,但部分站位DDTs含量介于其相应的ERL和ERM之间。

Based on the investigation of heavy metals (Cu, Pb, Cd, Zn, Cr, Hg, As) and DDTsPCBs in 36 surficial sediment samples collected from Guangxi sea area, the spatial distribution were discussed and integrative pollution effect of persistent toxic substances were evaluated. The results showed that the average concentration of heavy metals ( X 10^-6, dry wt) followed the sequence of Zn(49. 4 )>Cr (41. 7)> Cu (21. 5)>Pb (15. 6)>As (9. 1)>Cd (0. 07)>Hg (0. 026), and the average concentration of DDTs, PCBs (10^-9, dry wt) were PCBs (2. 97)>DDTs (0. 88), respectively. Average content of heavy metals, DDTs and PCBs of all the sampling sites were lower than the first class regulated by the GB 18668-2002. The potential ecological risks followed by Hg>As>Cd>Cu>Pb>Cr>Zn, and the RI was 19. 51, indicating a low potential ecological risk at Guangxi sea area. The high value in the Maowei Sea and the Lianzhou Bay was mainly due to the high potential risk of As and Cu. The concentrations of DDTs and PCBs indicated that Guangxi sea area had a low potential ecological risk, but The concentrations of DDTs of several sampling sites were between ERL and ERM.