模拟酸雨对茶园土壤中铅的溶出及形态转化的影响

Effects of Simulated Acid Rain on Dissolution and Transformation of Lead in Tea Plantation Soil

采用模拟酸雨连续淋洗的方法,研究了茶园土壤的酸化以及不同铅污染程度土壤中铅的溶出和形态转化规律。结果表明,土壤的酸化程度受酸雨酸性强度的控制,酸雨pH越低,土壤酸化程度越强;土壤中铅的溶出总量随模拟酸雨的酸度和土壤本身含铅量的增加而增加,但是土壤滤液中铅含量随时间变化的规律只受模拟酸雨的pH影响;土壤铅污染程度越严重,其中的活性态铅含量越高,同时pH<4.5的酸雨会使土壤中的非活性态铅大量向活性态转化,这将导致土壤中铅的活化而增加其生态风险。

Through continuous simulated acid rain, the releasing characteristics and the transformation of lead in tea plantation soil with different contents of lead were studied. The results show that the leaching of acid rain induces increase of soil acidity; the lower pH value of acid rain is, the more severe acidification occurs in the soil. The amount of lead released from the soil increases with the decrease in pH value of acid rain and with the augment of content of lead. But the curve＇s characteristics of lead in the filtrate from the soil are only affected by pH value of acid rain. The activity of lead is boosted with the increase of total lead, and the acid rain with pH 〈 4.5 will greatly enhance activity of lead, so the environmental risk is higher in this case.