Uneven Geography of Freshwater Environmental Stress Across India: Identifying Hydrochemical and Microbial Vulnerability Hotspots
Keywords:
freshwater quality, hydrochemical stress, microbial vulnerability, environmental hotspots, IndiaAbstract
Freshwater quality varies substantially across India because hydrochemical deterioration and microbial contamination are shaped by diverse environmental and anthropogenic pressures. This study assessed the geographical distribution of freshwater environmental stress and identified relative vulnerability hotspots by integrating hydrochemical and microbial indicators. The analysis included 121 observations from 117 monitoring locations across 11 Indian states, covering rivers, canals, ponds, lakes, and a creek. Temperature, dissolved oxygen (DO), pH, conductivity, biochemical oxygen demand (BOD), nitrate-N, fecal coliform, and total coliform were evaluated. Standardized indicators were integrated into Hydrochemical Stress, Microbial Vulnerability, and Integrated Freshwater Vulnerability indices. Spearman correlation and quartile-based hotspot classification were performed in Python. Fecal and total coliform showed the strongest positive association (ρ = 0.634), while BOD was inversely related to DO (ρ = −0.404). Hydrochemical and microbial vulnerability were weakly associated (ρ = −0.111, p = 0.254), indicating distinct stress dimensions. Agra Canal at Madanpur Khadar recorded the highest integrated vulnerability, while very-high vulnerability observations were geographically uneven. Integrated monitoring can therefore improve identification of priority freshwater systems and support geographically targeted pollution management.
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