兴化湾表层海水和沉积物中重金属含量的时空变化特征

根据福建兴化湾2006年12月（冬季）和2007年4月（春季）表层海水以及2007年3月表层沉积物的监测资料，分析了该海域表层海水和沉积物中重金属Cu、Pb、zn、Cd、Hg和As含量的时空变化特征，评价了该海域重金属的污染程度．结果表明：冬季，调查海域表层海水中cu、Pb、zn、cd、Hg、As的含量范围分别为〈0．20～2．42、〈0．03～1．08、〈3．1～16．5、〈0．010—0．043、〈0．007～0．170、0．82～4．00肌g／dm’；春季其含量范围分别为0．91～3．80、0．18～3．40、8．7～36．0、〈0．Ol～0．22、〈0．007～0．063、0．63～1．58~g／dm’．这两季表层海水重金属的测值均低于《海水水质标准（GB3097—1997）》第二类标准值，其中春季cu、Pb、zn、cd含量的均值高于冬季，可能与陆源重金属污染物入海的影响有关．兴化湾表层沉积物中cu、Ph、zn、Cd、Hg和As的含量范围分别为7．60～22．oo、22．4～39．1、54．2～114．0、0．045～0．082、0．020～0．066、5．00～10．20mg／kg，均低于《海洋沉积物质量（GB18668_2002）》的第一类标准值．该湾表层海水和沉积物中重金属含量的平面分布特征呈近岸海域较高．此外，对其历年来监测结果的比较表明，兴化湾表层海水和沉积物中cu和Ph含量的多次监测值较接近，但重金属zn含量的监测值存在着波动现象．

Spatio-temporal variation characteristics of heavy metal contents in the surface seawater and marine sediments of Xinghua Bay

The spatio-temporal variation characteristics of heavy metals,such as Cu,Pb,Zn,Cd,Hg,and As contents,were investigated in surface seawaters collected in Xinghua Bay,Fujian Province,China in December 2006(winter) and April 2007(spring) and marine surface sediments collected in March 2007.Our analyses showed that the contents of Cu,Pb,Zn,Cd,Hg,and As in surface seawaters ranged<0.20~2.42,<0.03~1.08,<3.1~16.5,<0.010~0.043,<0.007~0.170,0.82~4.00 μg/dm3 in winter,and ranged 0.91~3.80,0.18~3.40,8.7~36.0,<0.01~0.22,<0.007~0.063,0.63~1.58 μg/dm3 in spring,respectively.The respective average contents of Cu,Pb,Zn,and Cd in surface seawaters in spring were higher than those in winter,which might be due to many more pollutants from land sources in spring.The contents of Cu,Pb,Zn,Cd,Hg,and As in marine surface sediments ranged 7.60~22.00,22.4~39.1,54.2~114.0,0.045~0.082,0.020~0.066,5.00~10.20 mg/kg,respectively.All heavy metal contents in surface seawaters and marine surface sediments were lower than the standard values of categories II and I of the seawater and the marine sediment quality standard,respectively.The heavy metal contents in surface seawaters and marine surface sediments in the nearshore areas were higher than those in the offshore areas.Recent observations over past years have shown that the contents of Cu and Pb in surface seawaters and marine surface sediments were very close to that of the historical observation results;however,the monitored values of heavy metals,such as Zn,fluctuated.