Abstract：
Uncontrolled coal mining using non-scientific methods has presented a major threat to the quality of environment, particularly the water resources in eastern himalayan sub-region of India. Water bodies in the vicinity of mining areas are contaminated by acid mine drainage (AMD) that is released into streams and rivers. This study attempted to assess the impact of AMD, deciphering hydrogeochemical processes, seasonal fluctuations, and stable isotope features of water bodies flowing through and around coal mining areas. Self-organizing maps (SOMs) used to separate and categorize AMD, AMD-impacted and non-AMD impacted water from the different study locations for two sampling seasons revealed four clusters (C), with C1 and C2 impacted by AMD, C3 and C4 showing negligible to no impact of AMD. AMD impacted water was SO42- - Mg2+- Ca2+ hydrochemical type with sulphide oxidation and evaporation dominating water chemistry, followed by silicate weathering during both the sampling seasons. Water with negligible-to-no AMD-impact was Mg2+- Ca2+- SO42- to Ca2+ - HCO3- to mixed hydrochemical type with rock weathering and dissolution, followed by ion exchange as major factors controlling water chemistry during both the sampling seasons. Most of physicochemical parameters of C1 and C2 exceeded the prescribed limits, whereas in C3 and C4 water samples, parameters were found within the prescribed limits. Stable isotopes of hydrogen (δ2H) and oxygen (δ18O) during post-monsoon (PoM) varied between -41.04 ‰ and -29.98 ‰, and -6.60 ‰ to -3.94 ‰; and during pre-monsoon (PrM) varied between -58.18 ‰ and - 33.76 ‰ and -8.60 ‰ to -5.46 ‰. Deuterium excess (d-excess) ranged between 1.57 ‰ and 12.47 ‰ during PoM and 5.70 ‰ to 15.17 ‰ during PrM season. The stable isotopes analysis revealed that evaporation, mineral dissolution and mixing with rainwater are the key factors in study area.
摘要：
使用非科学方法进行不受控制的煤炭开采对环境质量构成了重大威胁，特别是印度喜马拉雅东部次区域的水资源。矿区附近的水体受到酸性矿山排水（AMD）的污染，该排水被释放到溪流和河流中。这项研究试图评估AMD的影响，破译水文地球化学过程，季节性波动，以及流经煤矿区和周围的水体的稳定同位素特征。自组织地图（SOM）用于分离和分类AMD，来自不同研究地点的两个采样季节的AMD影响和非AMD影响的水显示出四个簇（C），C1和C2受AMD影响，C3和C4显示出AMD的可忽略至无影响。AMD影响水为SO42--Mg2-Ca2水化学类型，硫化物氧化和蒸发主导水化学，其次是硅酸盐风化在两个采样季节。具有可忽略至无AMD影响的水为Mg2-Ca2-SO42-至Ca2-HCO3-与岩石风化和溶解的混合水化学类型，在两个采样季节，离子交换是控制水化学的主要因素。C1和C2的大多数物理化学参数超过了规定的限值，而在C3和C4水样中，参数在规定的范围内找到。季后（PoM）期间氢（δ2H）和氧（δ18O）的稳定同位素在-29.98‰至-41.04‰和-6.60‰至-3.94‰之间变化；在季风前（PrM）期间，变化在-58.18‰至-33.76‰和-8.60‰至-5.46‰之间。氘过量（d-过量）在PoM期间的范围为12.47‰至1.57‰，在PrM季节为15.17‰至5.70‰。稳定的同位素分析表明，蒸发，矿物溶解和与雨水混合是研究区的关键因素。
