化学添加剂对土壤和莴笋中重金属残留量的影响试验

Effects of chemical additives on the residual amount of heavy metals in soil and asparagus lettuce

针对重庆市蔬菜重金属污染现状,选取Hg、Cd、Pb为优先控制的目的重金属,通过盆栽试验,研究了石灰、腐殖酸、硫化钠等化学添加剂对莴笋吸收土壤重金属的效应及土壤重金属的残留机理。研究表明:适当剂量的石灰、腐殖酸能显著抑制莴笋对Hg的吸收,增加土壤中Hg的含量;而Na2S则能显著抑制莴笋对Pb的吸收,增加土壤中Pb的含量。从农产品安全要求出发,在试验条件下,抑制Hg、Cd、Pb进入莴笋体内的最佳化学物质及剂量分别为:石灰施用量为10.0g/kg、腐殖酸施用量为2.67g/kg时,抑制Hg进入莴笋体内的效果最好;石灰施用量为10.0g/kg时抑制Cd进入莴笋体内的效果最好;石灰、腐殖酸、硫化钠施用量分别为10.0、2.67g/kg和0.47mg/kg时抑制Pb进入莴笋体内的效果最好。

Based on current situation of heavy metal contamination of vegetables in Chongqing, potted-plant experiments were conducted to investigate the effects of certain chemical additives, such as limestone, humic acid, and sodium sulfide, on heavy metal uptake of asparagus lettuce and concerning mechanism in soil. Results showed that proper input of limestone and humic acid could significantly reduce mercury concentration in asparagus lettuce, whereas sodium sulfide could reduce lead uptaken by asparagus lettuce. According to the safety of agricultural products, the best chemical additives and their dosages which could reduce mercury,cadmium, and lead were obtained. Application of 10.0 g/kg of limestone, and 2.67 g/kg of humic acid sulfide had the most effective results on reduction of mercury in asparagus lettuce, and input of 10. 0 g/kg of limestone could most effectively decrease the cadmium concentration in asparagus luttce. Meanwhile, 10.0 g/kg of limestone, 2.67 g/kg of humic acid, and 0.47 mg/kg of sodium sulfide could best reduce lead concentration inasparagus lettuce.