珠江河口的现代沉积环境与底质重金属的含量分布

MODERN SEDIMENTARY ENVIRONMENT AND HEAVY METAL CONTENT DISTRIBUTION IN BOTTOM LOAD IN PEARL ESTUARY

引用在珠江口多年的环境污染监测资料和近期珠江口海岛资源综合调查的资料,并引用珠江口河口湾较典型的现代沉积相,分析探讨了河口湾的沉积环境与底质重金属的含量分布的密切关系。河口湾的水动力条件是近海沉积重要的动力因素。河口湾的沉积环境主要是受迳流及远距离搬运而来的陆源污染物的影响。河口湾表层沉积物的铜、铅、锌、镉的含量分布主要特征是:(1)珠江河口湾表层沉积物是以粉砂质粘土沉积为主,底质的重金属污染主要受沉积环境的影响,重金属含量一般偏高;(2)重金属含量分布,高值区多集中于沿岸的潮滩区域,大部分的表层沉积物的含量均存在有超标现象。

In the light of typical modern sedimentary facies in the Pearl estuary,the relationship between sedimentary environment and the content distributional pattern of heavy metals in the estuary is discussed using the monitoring data of environmental pollution over the years and recent comprehensive investigation data of island resources in the estuary. The hydraulic conditions in the estuary is the major dynamic factor influencing offshore sedimentation. The sedimentary environment in the estuary is affected by runoff and pollutants carried over long distance from land sources. The content distributional pattern of Cu, Pb, Zn and Cd in the surface layer of the estuary is that 1) silty clay sedimentation dominates in the surface sediment of the estuary with heavy metal content being higher; 2) the higher content value of heavy metals concentrates in tidal flat alongshore, with most metal values in surface sedimentation going beyond the criterion set for normal seawater.