寿光设施蔬菜土壤有效态Hg、As、Cu和Zn含量的变化

Available Hg,As,Cu and Zn content in vegetable Greenhouse soil of Shouguang

以山东寿光连作2、5、8、12年的设施土壤为材料,临近地块的露天麦地土壤为对照,研究了有效态Hg、As、Cu和Zn含量的变化.结果表明,有效态重金属在0～20 cm的表土层含量最多,由表层向底层逐渐减少,表聚性为有效态Hg>As>Cu>Zn.随着设施蔬菜种植年限的延长,有效态Hg、Cu和Zn含量不断增加,特别是种植5年以上的菜地,有效态增加速度加快.而土壤有效态As正相反,随设施年限的延长有逐渐减少的趋势.有效态重金属含量与土壤pH变化表现出显著或极显著的负相关性,有效态重金属之间多数表现出极显著的正相关性,说明重金属污染具有伴生性特征.

The temporal changes of the contents of available Hg, As, Cu and Zn in greenhouse soil were investigated. Soils that underwent different periods （2, 5, 8, 12 years） of continuous cropping were taken from Shouguang, Shandong province, while the control samples were taken from near open field plots of the planting wheat. The results demonstrated that the contents of heavy metals in surface layer （0—20 cm） were the highest, and gradually decreased from the surface layer to the deep layer, with a trend of the surface accumulation ability of available Hg 〉As〉Cu〉Zn. The content of available Hg, Cu and Zn increased with the extension of the continuous cultivation years of greenhouse, especially the greenhouse with over 5 years＇ planting. In contrast, the content of available As decreased with greenhouse planting years. Significant negative correlation existed between the contents of available heavy metals and soil pH, and significant positive correlation existed among most heavy metals, indicating that heavy metals are associated with each other during contamination .