Monitoring the dynamics of acid mine drainage affected stream surface water hydrochemistry at Jaintia Hills, Meghalaya, India.

Abstract

Streams are pristine natural life-thriving water sources for people living in the mountainous proximity of NE India, where water scarcity is a common occurrence in most villages and towns. In the last few decades, factors like coal mining had drastically reduced the usability of stream water in the region; as such, an attempt has been made to assess the spatiotemporal variation of stream water chemistry affected by acid mine drainage (AMD) at Jaintia Hills, Meghalaya. The water variables were subjected to a multivariate statistical technique of principal component analysis (PCA) to understand their condition at each sampling point while comprehensive pollution index (CPI) and water quality index (WQI) was incorporated to assess the quality status. Maximum WQI was recorded in S4 (541.14) during summer, while minimum value was estimated in winter at S1 (14.65). Throughout the seasons, the WQI revealed "Good" quality in S1 (unimpacted stream), while the impacted streams (S2, S3, and S4) exhibited a "Very poor" to "Water unsuitable for drinking" status. Similarly, in S1, the CPI showed a ranged value of 0.20 to 0.37, presenting a water quality status of "Clean to Sub-Clean," whereas, CPI of the impacted streams indicated "Severely polluted" status. In addition, PCA bi-plot presented higher affinity of free CO2, Pb, SO42-, EC, Fe, and Zn in AMD-impacted streams than in unimpacted streams. The result demonstrates the environmental issues induced by coal mine waste and in particular, stream water being severely affected by AMD in mining areas of Jaintia Hills. Thus, measures to stabilized the mine repercussions and cumulative effects on the water bodies need to be formulated by the government, as stream water will remain the primary water source for the tribal communities in this region.