Water safety assessment and related health concerns of four districts of nagaland: a physicochemical and statistical investigation

Access to safe drinking water remains a persistent challenge in Nagaland, India, due to limited infrastructure, rapid urbanization, and sparse monitoring of water resources. This study evaluates the quality of drinking water across four districts by analysing 28 samples collected from rivers, streams, and wells, considering 13 key physicochemical parameters: pH, temperature, total dissolved solids (TDS), electrical conductivity (EC), dissolved oxygen (DO), total hardness (TH), nickel (Ni), aluminium (Al), sulphate (SO₄²⁻), phosphate (PO₄³⁻), calcium (Ca), magnesium (Mg), and total organic carbon (TOC). Water Quality Index (WQI) and Pearson correlation analysis were applied to identify dominant factors and interdependencies. Most parameters complied with BIS standards; however, aluminium and nickel exceeded permissible limits in several rural sites, highlighting potential long-term neurological and systemic health concerns, though causal effects are not claimed. WQI values ranged from 10.5 (excellent) to 90.9 (very poor), reflecting substantial spatial variation, particularly in Phek, Peren, and Kiphire. Correlation patterns indicate that water quality is largely influenced by physical parameters such as pH, TDS, and EC, while aluminium and nickel drive localized contamination. This study establishes a first multi-district, statistically integrated baseline of drinking-water quality in Nagaland, supporting future monitoring and evidence-based interventions. The findings provide critical insight for targeted water-safety management and priority actions to mitigate contamination in both rural and urban areas.