山口红树林保护区英罗港表层沉积物重金属形态的分布特征

Distribution Characteristics of Heavy Metal in Surface Sediments of Yingluo Bay in Shankou Mangrove Reserve

关键词:  重金属形态  红树林  粒度  英罗港  分布

Key words:  heavy metal speciation  mangrove  particle size  Yingluo Bay  distribution

摘要:

通过对广西山口红树林自然保护区英罗港红树林湿地表层沉积物粒度和重金属Zn、Cu、Pb、Cd的分析，探讨重金属在红树林表层沉积物中的存在形态和分布规律。本文发现英罗港红树林林内表层沉积物粉砂和黏土所占比例高于光滩，并且林内沉积物Zn、Cu、Pb、Cd含量均高于光滩。表层沉积物中粉砂和黏土所占比例与重金属含量呈显著正相关，符合重金属的粒度效应。英罗港表层沉积物Zn、Cu、Pb、Cd平均含量低于国内其他主要红树林生长区域，表明该地区表层沉积物重金属污染相对较小。英罗港红树林沉积物重金属主要存在形态为残渣态，表明该区域重金属元素生物有效性较小。红树林林内沉积物非残渣态可氧化态重金属所占比例较高，这与红树林沉积物富含有机质和硫化物有关。光滩沉积物可还原态所占比例较高，这可能是光滩沉积物的砂质较多，通气性好，呈现氧化性的结果。

Abstract:

By analyzing the sediment size and heavy metals Zn, Cu, Pb, and Cd in the Yingluo Bay mangrove wetland in Guangxi Shankou National Mangrove Reserve, the forms and distribution of heavy metals in mangrove surface sediments were explored. This paper finds that the proportion of silt and clay in the forest surface sediments in Yingluo Bay were higher than that in bare mudflat, and the contents of Zn, Cu, Pb and Cd in the sediments in the forest are also higher than that in bare mudflat. The proportion of silt and clay in surface sediments is significantly positively correlated with the content of heavy metals, which is consistent with the particle size effect of heavy metals. The average content of Zn, Cu, Pb and Cd in the surface sediments of Yingluo Bay is lower than that of other major mangrove growth areas in China, indicating that the heavy metal pollution of surface sediments in this area is relatively small. Heavy metals in mangrove surface sediments in Yingluo Bay are mainly in residual state, indicating that the bioavailability of heavy metals in this area is relatively small. In the non-residual state, the proportion of oxidizable heavy metals in forest sediments is higher, which is related to the abundance of organic matter and sulfides in the sediments in the growth area of mangroves. The proportion of bare mudflat sediments in the reducible state is relatively higher, which may be due to the results that the sediments in bare mudflat are full of more sand, have good aeration, and exhibit oxidative.