莲花山矿区土壤-农作物系统中重金属调控

以广东省莲花山钨矿区耕地为研究点，研究土壤金属含量分布、形态特征及其调控措施。分析耕地土壤中Zn、Cu、Mn、Ni、Pb、Cd、As含量特征，以碱石灰、MnO2、Fe2O3和钙镁磷肥作为改良剂，对矿区污染耕地土壤进行改良，并种植萝卜Raphanus sativus，分析各改良剂对土壤金属形态及其在土壤-农作物界面迁移的影响。研究表明，矿区耕地土壤酸化， Zn、Mn、Pb、Cd和As超过土壤背景值，其中Cd和As污染严重，分别超过背景值的10.2-16.7倍和1.1-1.3倍。碱石灰有效降低耕地土壤pH值，降低土壤Zn、Cu、Mn、Ni、Pb、Cd可溶态含量，减少其在萝卜中积累。萝卜对Pb、Zn、Cd、Cu、Ni累积量与其可溶态含量相关性显著，与总量相关性不显著。Fe2O3、MnO2、钙镁磷肥对耕地土壤Zn、Cu、Ni、Mn、Pb、Cd 生物有效性及其在农作物中累积量无显著影响。矿区耕地土壤分别添加碱石灰、Fe2O3、MnO2，土壤中砷松散结合态含量降低，农作物砷累积量减少。钙镁磷肥对土壤砷形态无显著影响，但能显著降低萝卜中砷的累积量。碱石灰分别与Fe2O3、MnO2、钙镁磷肥相结合改良耕地土壤，比单一改良剂更能有效降低萝卜中砷的累积量。萝卜中砷累积量与松散结合态存在显著正相关性，与Ca-As存在显著负相关性。碱石灰分别和Fe2O3、钙镁磷肥同时加入土壤，能同时地有效降低Zn、Cu、Mn、Ni、Pb、Cd、As的有效性，及其在农作物累积量，因此，这2种改良方式是莲花山矿区土壤金属固定的有效措施。

Regulation on metals in plant-soil system in Lianhuashan tungsten mine area

The study targeted the arable soils in Lianhuashan tungsten mine area in Guangdong Province and investigated metals pollution and regulation of metals in the arable soils. The arable soils in Lianhuashan tungsten mine area were analyzed for Zn, Cu, Mn, Ni, Pb, Cd and As. Soda lime, MnO2, Fe2O3 and calcium magnesium phosphate were applied to amend the metals-polluted arable soils in which was planted by radish. Effects of substrate amendments on metals fraction and migration in plant-soil system were also investigated. The results showed that the arable soils were polluted by Zn, Mn, Pb, Cd and As, especially Cd and As, which were 10.2-16.7 and 1.1-1.3 times more than background values, respectively. Soda lime decreased soluble Zn, Cu, Mn, Ni, Pb and Cd contents, and their accumulations in the radish. Fraction of Zn, Cu, Mn, Pb and Cd in the arable soils and their accumulations in the radish were hardly affected by Fe2O3, MnO2 and calcium magnesium phosphate. Zn, Cu, Cd, Cu, Pb and Ni accumulations in radish were significantly and positively correlated with their soluble contents, but were not significantly correlated with the total heavy metal contents. Applications of soda lime, MnO2 or Fe2O3 significantly decreased the concentrations of loosely sorbed arsenic and arsenic accumulation in radish. Calcium magnesium phosphate had little effect on arsenic fraction, but decreased arsenic accumulation in radish. In addition, application of soda lime with MnO2, Fe2O3 or calcium magnesium, respectively, reduced arsenic accumulation in radish more effectively than a single one. Arsenic accumulation in radish had significant positive correlation with loosely sorbed arsenic content and significant negative correlation with Ca-As content. Addition of soda lime with Fe2O3 or calcium magnesium, respectively, is effective amendments to decrease metals and arsenic accumulation in radish in the arable soils around Lianhuashan tungsten mine area.