Impact of Coal Mining on the Tzuong River System of Mokokchung, Nagaland

Abstract

The Changki valley area is traditionally regarded as the rice bowl region providing the supply of stable food to a large population of the Ao Naga tribe dwelling in the foothill regions of Nagaland, India. Rampant and unscientific coal mining in and around the Changkikong range has painted a grim future for the area due to severe environmental degradation. Mine tailings and the lack of treatment or mitigation measures have led to the spread of acid mine drainage (AMD) in nature and are the primary source of contaminants for the Tzuong River system. The pollution has also threatened the livelihood of the indigenous people and endangered numerous aquatic species that once thrived in these streams with extinction, some of which are still yet to be identified. Fourteen samples of water are collected at the Tzuong river as well as from its tributaries for physicochemical analyses. Results show that the natural water is significantly compromised and is highly acidic besides high total dissolved solids (TDS), iron and copper concentrations. Assessment of the index of water quality (WQI) by employing the weighted arithmetic indexing (WAI) approach categorizes the stream waters under “unsuitable for drinking purpose” status with WQI scores >100.