降雨对废弃尾矿分层土壤重金属铜铅锌的淋滤释放影响规律研究

为探究废弃尾矿中三种典型重金属元素Cu、Pb、Zn在不同降雨pH值、降雨强度以及降雨历时综合影响条件下的淋滤释放变化规律，以辽宁省辽阳县寒岭镇某废弃尾矿库为对象，在实验室内配制与现场实际情况相符的不同污染程度的土壤样品，采用大型土柱分层装填，模拟降雨进行淋滤试验。研究发现：（1）pH值越低各出水口淋出液中铜铅锌的含量均越大，酸性淋滤下的重金属浓度相比碱性淋滤要更高，3种重金属的累积释放量为Zn>Pb>Cu；（2）底部出水口重金属浓度一直保持是最大的，各土柱溢流口淋出液的重金属浓度不为0；（3）总体上，淋出液中的重金属Cu、Pb、Zn含量均随着降雨强度的增大呈增加趋势；（4）在酸性降雨条件下，淋出液中铜、铅、锌的含量也均随淋滤时间的增大呈增加趋势，弱碱性淋滤条件下则正好相反。

Influence of rainfall on leaching and release of heavy metals copper, lead and zinc from stratified soil of waste tailings

To explore the abandoned tailing of three typical heavy metal elements Cu, Pb, Zn in different pH rainfall, rainfall intensity and rainfall duration comprehensive effect under the condition of leaching release the change rule, taking an abandoned tailings pond in Hanling Town, Liaoyang County, Liaoning Province as the object, prepared in the laboratory accords with the actual situation of different pollution degree of soil samples, The leaching test was carried out by using a large soil column to simulate rainfall.The results show that :(1) The lower the pH value, the higher the content of copper, lead and zinc in the leaching solution of each outlet, and the concentration of heavy metals in acidic leaching is higher than that in alkaline leaching and the cumulative release amount of three heavy metals is Zn>Pb>Cu. (2) The heavy metal concentration in the bottom outlet is always the maximum, and the heavy metal concentration in the leachate from the overflow outlet of each soil column is not 0.(3) Overall, the contents of heavy metals Cu, Pb and Zn in the leaching solution increased with the increase of rainfall intensity. (4)Under the condition of acidic rainfall, the contents of copper, lead and zinc in the leaching solution also increased with the increase of leaching time, while under weak alkaline leaching conditions, it was just the opposite.