PHYSIOCHEMICAL ASSESSMENT OF SEWAGE AND GROUNDWATER AND ITS IMPACT ON SOIL QUALITY IN RATANGARH TEHSIL, CHURU DISTRICT

Abstract

Owing to increasing water scarcity and dependence on untreated sewage water for irrigation in the Ratangarh (Churu) region, a systematic analysis was undertaken to understand the extent of environmental degradation and potential risks to agriculture and human health. The present study evaluates the physicochemical characteristics of sewage water, groundwater, and soil in Ratangarh tehsil of Churu district, Rajasthan. The results revealed notable variations in water and soil quality, with sewage water exhibiting elevated levels of dissolved solids, nutrients, and contaminants compared to groundwater. Continuous use of sewage water for irrigation was found to influence soil properties, particularly salinity, nutrient imbalance, and accumulation of trace metals, leading to gradual degradation of soil quality. Sewage water analysis showed high electrical conductivity (2.64– 4.45 mS/m), organic carbon (812–942 mg l⁻¹), nitrogen (116–188 mg l⁻¹), sulphur (44.8–66.7 mg l⁻¹), and phosphate (0.61–4.10 mg l⁻¹). Trace metal assessment revealed iron (1.49–2.86 mg l⁻¹), copper (0.12–0.79 mg l⁻¹), zinc (0.13–1.35 mg l⁻¹), manganese (0.28–0.70 mg l⁻¹), chromium (0.12–0.19 mg l⁻¹), nickel (0.17–0.27 mg l⁻¹), lead (0.02–0.09 mg l⁻¹), and critically elevated cadmium (4.23–9.30 mg l⁻¹), exceeding CPHEEO limits. Soil samples from sewage-irrigated areas showed pH values of 7.03– 7.23, EC of 1.01–1.99 dS/m, organic carbon of 0.39–0.97%, and excessive accumulation of nitrogen (35–196 mg kg⁻¹), phosphorus (27–35 mg kg⁻¹), and potassium (31–96 mg kg⁻¹). Groundwater samples exhibited high EC (2.45–5.20 dS/m), TDS (1214–2286 mg l⁻¹), hardness (274–808 mg l⁻¹), and magnesium (47–104 mg l⁻¹), resulting in moderate to poor water quality (WQI: 46.9–123.9). The findings indicate that while sewage irrigation provides short-term nutrient benefits, its prolonged use leads to soil degradation, roundwater deterioration, and potential risks to crop safety and human health