近10年渤海湾重金属(Cu,Zn,Pb,Cd,Hg)污染时空变化趋势分析

Temporal-Spatial Variation Trend Analysis of Heavy Metals(Cu,Zn,Pb,Cd,Hg)in Bohai Bay in 10 Years

渤海湾的污染问题已成为其进一步开发利用的主要瓶颈之一,然而以往有关渤海湾污染问题的研究以营养盐为主,而海水重金属污染研究较少.本研究通过均值柱状图分析、方差分析、曼-肯德尔检验法(Mann-Kendall)、反距离插值等方法研究了渤海湾近10年来海水中重金属的污染状况及时空变化趋势.结果表明,渤海湾海水以可溶态Zn、Pb、Hg污染为主,Cu、Cd污染较轻.10年来,每种重金属在枯、丰、平3个监测时期含量差异性不显著,但时间序列变化规律性差异性较大.各种重金属含量变化的突变时期各不相同.空间分析结果表明,各种重金属均表现为近岸高离岸低的特性,除Cu元素表现为北高南低的规律以后,其他重金属都表现为南高北低的空间趋势.陆源污染、海洋养殖、海上石油开采、大气降尘等都是渤海湾可溶态重金属的主要污染来源.

The pollution of Bohai Bay has become the major limit to its further development. Most of the existing researches concentrate on the nutritional salt pollution while little attention has been paid to the heavy metals pollution in seawater. In this study,histogram analysis of average value,variation analysis,Mann-Kendall test and inverse distance weighted interpolation were applied to the analysis of the pollution level and temporal-spatial variation trend of heavy metals （Cu,Zn Pb,Cd,Hg） in Bohai Bay in these 10 years （1996--2005）. Study results show that the seawater in Bohai Bay is mainly polluted by Zn,Pb and Hg and only slightly polluted by Cu and Cd. Concentrations of each heavy metal in the drought period, wet period and common period do not have significant differences,while time series trend and concentration sudden change period of each heavy metal were also different. Spatial analysis indicates that the concentrations of all heavy metals have similar trend,decreasing from near-shore to off-shore,and decreasing from south to north except Cu. Land-based pollution, sea water aquaculture, offshore oil exploitation and air fall dust are the major sources of heavy metal pollution in Bohai Bay.