岩溶山区煤矸石堆场重金属淋溶迁移特征及其对周边水体质量的影响

Characteristics of Heavy Metal Leaching and Migration in Coal Gangue Yard and its Impact on the Quality of Surrounding Water Bodies in Karst Mountainous Areas

为探讨岩溶山区煤矸石堆场重金属淋溶迁移特征及其对周边水体质量的影响,对贵州省中部不同类型煤矸石淋溶液、地表径流、周边水体重金属进行了分析。结果显示,坡积型煤矸石淋溶液中重金属浓度明显高于残积型煤矸石,重金属浸出浓度大小顺序为Fe>Mn>Zn>Cu>Cr>Pb>Cd,Fe、Mn质量浓度范围分别是1.65~6.71,0.82~3.09 mg/L,均超出了《污水综合排放标准》(GB 3838—2019)的限值,两种类型煤矸石淋溶液中重金属浓度受降雨量影响较大;不同类型煤矸石堆场地表径流中重金属浓度差异较大,坡积型煤矸石地表径流中重金属浓度明显高于残积型煤矸石,Fe、Mn浓度在6月份最低,8月份较高,浓度变化受降雨强度的影响;岩溶地区水质受煤矸石堆场重金属迁移的影响逐渐变小,阿哈湖水库入库口水体依然有轻微的Fe、Mn污染。本研究结果为溶山区煤矿区煤矸石堆场的生态环境治理及生态修复提供了科学依据。

In order to explore the leaching migration characteristics of heavy metals in coal gangue dump in karst mountain areas and its influence on the quality of surrounding water bodies,different types of coal gangue leaching solutions,surface runoff and heavy metals in surrounding water bodies in central Guizhou Province were analyzed.The results show that the concentration of heavy metals in the leaching solution of slope-accumulated coal gangue is obviously higher than that of residual coal gangue,and the leaching concentration of heavy metals is in the order of Fe>Mn>Zn>Cu>Cr>Pb>Cd,and the concentration ranges of Fe and Mn are 1.65~6.71 mg/L and 0.82~3.09 mg/L,respectively,which all exceed the Comprehensive Wastewater Discharge Standard(GB 3838-2019).The concentration of heavy metals in surface runoff of different types of coal gangue yards is quite different.The concentration of heavy metals in surface runoff of slope-accumulated coal gangue is obviously higher than that of residual coal gangue,and the concentration of Fe and Mn is the lowest in June and higher in August,and the concentration change is affected by rainfall intensity.The water quality in karst area is gradually weakened by the migration of heavy metals in coal gangue dump,and there is still slight Fe and Mn pollution in the inlet of Ahahu Reservoir.The results of this study provide a scientific basis for ecological environment management and ecological restoration of coal gangue yard in coal mining area of Rongshan District.