模拟酸雨对污泥堆肥中重金属形态转化及其环境行为的影响

Effects of simulated acid rain on form transformation and environmental behaviors of heavy metals in amended sludge compost

通过模拟酸雨淋溶土柱的方法,研究了酸雨(pH=5.0和2.9)作用下污泥堆肥中Zn、Cu和Ni的溶出和迁移性,分析了酸雨对重金属形态分布规律的影响。结果表明,在相同酸雨强度下,淋出液中重金属含量与其在土柱中迁移距离大小次序为Zn>Cu>Ni;重金属在相同深度的土层中含量大小次序为Zn>Ni>Cu。淋溶液pH的降低和污泥堆肥施加比例的提高均会增加重金属在淋出液和土柱中的含量,但不影响重金属在土柱中的迁移距离。土壤酸化会促使土壤中重金属形态向活性形态转化,而且迁移距离增加。

In a simulation experiment with saline soil column, this paper studied the effects of acid rain （pH = 5.0 and 2.9） on the mobility and form transformation of Zn, Cu and Ni in amended sludge compost. The leachate was collected every other day over 42-day experiment, and the heavy metals in soil were fractionated by using sequential extraction method. The results showed that under the same acid rain intensity, the heavy metals content in leachate and their migration in soil followed the sequence of Zn 〉 Cu 〉 Ni, and the heavy metals content in the same soil depths was in the order of Zn 〉 Ni 〉 Cu. The decrease of acid rain pH and the increase of sludge compost dosage increased the heavy metals content in leachate and soil, but had no effect on their migration. Soil acidification promoted the transformation of heavy metals to activated forms and their migration to deeper soil.