Spatial distribution of physicochemical-bacteriological parametric quality and water quality index of Gomti River, India

Surface water bodies are vital source of water for human consumption, domestic needs, agriculture, industrial activities, and also for aquatic life and ecosystems. In this study, a stretch of river Gomti was studied at 5 sites in Lucknow for two consecutive seasons during 2019. The physicochemical-bacteriological parameters of water and sediment samples were analyzed, followed by multivariate statistics. Mean values of pH, turbidity, EC, TS, TDS, TSS, DO, BOD, COD, nitrate, phosphate, sulfate, total alkalinity, total hardness, chloride, and fluoride during the pre-monsoon period were 7.4 ± 0.2, 5.2 ± 3.3 (NTU), 444.4 ± 97.4 (µS/cm), 274.6 ± 61.6, 254.3 ± 50.2, 21.9 ± 11, 5.4 ± 1.6, 10.2 ± 5.9, 31.2 ± 13.3, 1.2 ± 0.5, 1.7 ± 1.1, 25.9 ± 3.7, 204 ± 41.8, 146.2 ± 11.5, 15.5 ± 8.7, and 0.5 ± 0.1 mg/l, respectively. The corresponding values during the post-monsoon season were 7.5 ± 0.2, 5.5 ± 3.2 (NTU), 436 ± 75.1 (µS/cm), 273.7 ± 124.2, 209.7 ± 82.5, 63.9 ± 43.4, 5.6 ± 1.6, 15.8 ± 8.9, 39.2 ± 23.5, 5.4 ± 4.6, 1.4 ± 0.9, 25.5 ± 5, 199.2 ± 36.6, 134 ± 8.6, 20.2 ± 8.9, and 1.7 ± 0.2 mg/l, respectively. Concentration of pollutants significantly increased by 5–15% from sampling station S1 (upstream) to S5 (downstream). Enumerations of fecal coliform and Escherichia coli bacteria were low at S1 but significantly higher at the S5 site. WQI ranged from 88 to 345 during pre-monsoon and 159 to 422 during post-monsoon period, indicating poor water quality which was unsuitable for drinking purposes. Strong positive correlations (≥ 0.9) were observed among pH, chloride, phosphate, sulfate, turbidity, conductivity, TS, TDS, BOD, and COD for water samples during both seasons. The data reveals that pollution load increases gradually from upstream to downstream due to the increasing discharge of raw sewage. Regulatory bodies should formulate strict regulations and ensure their implementation for the protection and management of river water quality.