王港潮滩重金属Pb、Zn和Cu的积累特征

对15a来王港潮滩重金属积累规律和污染状况进行了研究,第1次测到了王港地区210Pb的本底值为1.16dpm/g,校正了前人对王港地区沉积速率的研究。尝试性地把分形理论引入到环境压力的定量研究中。研究表明,王港潮滩现代平均沉积速率为4.13cm/a;从重金属相关性分析得出:王港潮滩Fe、Zn与Li相关系数非常显著,归一化后,Cu、Zn的归一化值在15a内相对稳定,其中Cu的波动范围在0.4～2之间,Zn在1.5～2.6之间狭小的范围内波动。分形回归分析结果表明,王港潮滩重金属Cu、Zn归一化值的信息维数高,系统的结构松散,自组织程度低。Cu的分维值范围在5～6.5,平均值为5.8085,Zn的分维值范围在在3～6.5,平均值为4.68。王港潮滩重金属的人为污染较轻,主要受地球化学元素的控制;同时,Pb的归一化值的分维值较低,其分维值范围在2～5.5,平均值为3.608,自组织程度较高,说明存在一定程度的Pb污染。

Key Laboratory of Coast and Island Development, Nanjing University, MoE, Nanjing 210093, China

The vertical accumulation of heavy metals and pollution status in Wanggang tidal flat were studied.The base value of 210Pb in Wanggang area was obtained as 1.16dpm/g.The fractal theories were led into the quantitative study of pollution issues.The modern average sedimentary rate in Wanggang area is 4.13cm/a,according to the 210Pb analysis.Through the relativity analysis of heavy metals,it is educed that the Fe,Cu,Pb,Zn and Li have better pertinence in the area.After normalization,Cu and Zn remain stable values in the past 15 years.Cu shifts its value from 0.4-2,Zn from 1.5-2.6.The normalized heavy metal information dimension is high in the area,with loose systematic structure and lower organizational degree.The fractal dimension value of Zn moves from 3-6.5,average is 4.68,contemporary Cu from 5~6.5,average is 5.8085.The study shows that the heavy metal distribution in the area is mainly controlled by local geochemistry character,with limited contribution from human activities.Meanwhile,the fractal dimension of Pb normalization value is lower,in the scope of its fractal dimension flow varies from 2 to 5.5,with an average of 3.608.Higher levels of self-organization of Pb mean a certain degree of lead contamination.