广西铁山港-雷州半岛近岸沉积单元重金属分布

SURFACE SEDIMENT HEAVY METAL DISTRIBUTION IN SEDIMENT UNITS OF GUANGXI TIESHANGANG SHIJIAOPU NEARSHORE

通过地形地貌与沉积物类型相结合,分析了广西铁山港-雷州半岛石角埠近岸不同沉积物单元重金属分布。结果表明,由于沉积环境的不同单元重金属含量与分布是有差别的,全区重金属含量为4.96×10-6～55.80×10-6,浅谷体系由于沉积环境比较稳定,重金属含量和丰度最高,依次在11.88×10-6～55.80×10-6与0.66～1.87之间,斜坡体系则以含量偏低,变异系数偏大为特征;重金属之间相关系数在0.20～0.98,表现为显著正相关或者无显著相关,在斜坡体系中的Pb、Zn、Cr之间,以及在浅谷体系中Cu、Zn、Cr之间,有共聚共散的特点,尚未有负相关关系存在;重金属与粒度、有机质关系比较密切,采用变化幅度比值(ΔM/M)/(Δφ/φ)表示的相对粒度灵敏度在-6.5～11.0之间,随着颗粒变细,含量增加,但在各单元表现不一。随着有机质含量增加,重金属Zn、Pb、Cu含量也呈现波动式增加;从沉积相与海水溶解相对比来看,Cr更具有向沉积相积累的趋向性,比值范围在5000～200000之间,其次是Pb,这与其性质和环境因子调控有关;依据沉积物质量标准,研究区重金属质量均为一类,质量指数为0.06～0.74,总体上较好。

Based on geomorphic and sediment types, the nearshore surface sediment heavy metal distri bution of Guangxi Tieshangang-Shijiaopu of I.eizhou Peninsular was analyzed. The results show that because of different sedimentary environment, the surface sediment distribution has their own charac- ters. Heavy metal concentration ranges from 4.96×10^-6-55.80×10^-6 in study area, and the concen- tration in shallow valley whose environment was somewhat stable, is relatively high and falls into the range of 11.88×10^-6-55. 80×10^-6; in slope system, the concentration was lower and the spatial vari ation was more apparent; the correlation index was 0.20-0.98, revealing non-relation and significant relation between metals; there was a closer relation between metals and grain and organic matter, and the metal concentration sensitivity to grain using （△M/M）/（△φ/φ） changes from--6.5 to 11.0; from the ratio of sediment phase/seawater dissolved phase, Cr had a more significant trend to sediment and its ratio was 5000420000; finally, the sediment quality was assessed under nation standards.