鄱阳湖及周边经济区土壤镉的含量与分布

Content and Distribution of Cadmium in Soils of Poyang Lake and Its Surrounding Economic Zones

采用双层网格布点法,在研究区分别采集表层和深层土壤样品9829和2467个,测定了样品的镉含量和pH值。表层土壤镉含量呈对数正态分布,含镉范围0.024~4.619mg/kg,宜用几何平均值0.157mg/kg表征其平均含量。深层土壤镉含量显著低于表层,含量范围0.010~1.982mg/kg,算术平均值和几何平均值分别为0.098mg/kg和0.080mg/kg。研究区7地市表层土壤镉含量几何平均值较30年前上升34.6%~165%。据《土壤环境质量标准GB15618-1995》,以镉为评价指标时,研究区以Ⅰ类土壤为主,分布面积占总面积的78.36%,次为Ⅱ类土壤、分布面积占总面积的15.92%,Ⅲ类和劣Ⅲ类土壤仅占总面积的5.72%,显示土壤环境质量良好,但仍须采取有效措施遏制镉污染的迅猛发展。

Two-layer grid method was employed for sampling. Surface soils at 0--20 cm and deep soils at 150--200 cm were collected at a sampling density of 1 sample per 4 km2 and 16 km2, respectively. 9829 surface soil samples and 2467 deep soil samples were collected in the studied areas. Cadmium concentration and pH value of these samples were determined. The contents of cadmium in surface soils show logarithm normal distribution, and cadmium values range from 0. 024 mg/kg to 4. 619 mg/kg, with the average cadmium content in surface soils in Poyang Lake and its surrounding economic zones designated as the geometric mean, 0. 157 mg/kg. Cadmium content in deep soils ranges from 0. 010 mg/kg to 1. 982 mg/kg, with its arithmetic and geometric mean of 0. 098 mg/kg and 0. 080 mg/kg, respectively, and they were significantly lower than those in surface soils. The geometric mean of cadmium contents of surface soils in the seven cities of the studied area has increased 34.6%- 165 % during the past 30 years. Although the cadmium environment quality in soils is good, with Class III and inferior class III soil only covering 5.72 % of the total areas. The effective measures should be adapted to control the rapid development of cadmium pollution.