珠江三角洲污灌区土壤中重金属含量特征

Heavy Metal Content Characteristics of Soil in Sewage Irrigation Area of Pearl River Delta

通过现场采样及室内测试方法,分析了珠江三角洲污灌区土壤中9种重金属Cd、Cu、Zn、Pb、Mn、Ni、As、Cr、Se的含量分布特征。结果表明,污灌区土壤9种重金属的全量平均含量均已超出广东省土壤背景值,其中Cd的污染程度最重,Se的污染程度最轻;污灌区土壤以Cd元素的有效系数最高,Ni元素的有效系数最低。Zn、Pb、Cu以及Cd元素随采样深度的增加其全量逐渐减少,Cr、Ni、As以及Se元素随采样深度的增加其全量呈上下波动状态或几乎不变,而Mn元素则是随采样深度的增加其全量先略有减少而后骤升。Cu、Cd、Zn等3种元素全量与有效态含量以及这3种元素全量间均呈显著或极显著的正相关关系。

With the rapid industrialization development in recent years, there are many sewage irrigation phenomenons in the Pearl River Delta. It is important to understand the distribution of heavy metals in soil in sewage irrigation area for soil pollution prevention and control planning in Pearl River Delta. The total content and available content of heavy metals（Cd, Cu, Zn, Pb, Mn, Ni, As, Cr and Se） in soil from sewage irrigation area in the Pearl River Delta were analyzed with 32 soil samples. The average content of total content of the nine heavy metals in soil from sewage irrigation area exceeded soil background value of Guangdong Province. Among of the nine heavy metals, Cd had the highest pollution degree, Se had the lowest pollution degree, Cd had the highest valid coefficient, and Ni had the lowest valid coefficient. The total contents of Cd, Cu, Zn and Ph decreased with the sampling depth increasing. The total contents of Ni, As, Cr and Se fluctuated or kept stable with the sampling depth increasing. The total content of Mn decreased firstly, and then rose remarkably with the sampling depth increasing. There was a remarkable or most remarkable positive correlation between total content and available content of Cd, Cu and Zn, and there was a remarkable positive correlation among of the total content of Cd, Cu and Zn, which indicated that the distribution of Cd, Cu, Zn and Pb in soil mainly affected by sewage irrigation.