摘要
选取珠江三角洲冲积平原区4个不同沉积相带的第四系岩心做元素全量分析,并对4种重金属进行了赋存形态分数分析,揭示了珠江三角洲第四系元素地球化学特征主要受物源和沉积环境的控制。不同沉积环境下物源的影响程度不同,物源在三角洲平原相的沉积环境下影响强度最大,在海陆交互强烈的沉积环境下,物源的影响减弱,海陆交互作用的影响增强。不同重金属元素由于自身化学性质的差异,其对沉积环境的敏感程度有所不同。研究区Cd富集显著,且其活性态比例最高、潜在生态风险最大;而As,Hg和Pb的富集程度较弱,且As和Hg主要以残渣态的形式存在,Pb主要以残渣态和铁锰氧化物态为主,它们的生态风险相对较低。不同的沉积环境下p H等理化指标对Cd形态的影响不同,Cd的活动态主要与p H和淋滤系数有关。
This paper analyzed contents and geochemical fractions of four heavy metals in four Quaternary boreholes from different sedimentary areas in Pearl River Delta. The results revealed that the geochemical features of heavy metals were controlled by geological provenance and sedimentary environment. The contribution rates of geological sources showed differentiation in four sedimentary environments. In delta plain sedimentary environment, geological sources were the most predominant. In the sea land interaction sedimentary environment, the control of the geological source factor was weakened. The effect of land-sea interaction became more important. Due to differ- ent chemical properties of heavy metals, they showed distinct sensitivities to sedimentary environment. Cadmium （Cd） was enriched significantly in the study areas. Mobile fraction of Cd possessed the highest proportion. Poten- tial ecological risk of Cadmium was the highest among heavy metals. Asenic, mercury and lead were enriched weakly. Arsenic and Mercury were dominated by residual fraction. Lead was mainly composed of residual and Fe- Mn oxidation fraction. Their potential ecological risks were relatively lower. In different sedimentary environment, physicochemical parameters had various effects on Cadmium geochemical fraction such as pH. The mobile fraction of Cd was mainly correlated with pH and leaching coefficient.
出处
《地球科学进展》
CAS
CSCD
北大核心
2017年第8期885-898,共14页
Advances in Earth Science
基金
中国地质调查局地质大调查项目"珠江三角洲土壤重金属地球化学成因与风险评价"(编号:12120115050401)
痕迹科学与技术公安部重点实验室开放课题(编号:2015FMKFKT03)资助~~
关键词
珠江三角洲
第四系
物源
海陆交互作用
重金属
Pearl River Delta
Quaternary
Provenance
Land-sea interaction
Heavy metal.
