Abstract

Purpose: This study investigates the environmental impact of vehicle washing station effluents on surface water quality in Gilgit City, Gilgit-Baltistan, Pakistan. With an increasing number of car wash stations washing 15–30 vehicles per day and consuming 150–350 liters per vehicle, large volumes of untreated wastewater are discharged directly into nearby streams. Research design, data and methodology: Wastewater samples were collected from three major stations—Nagaral, Dumiyal, and Danyore—and analyzed for physicochemical parameters (pH, turbidity, EC, TDS, salinity, K, PO₄, CaCO₃, and Na) using standard laboratory methods. Macroinvertebrates were sampled using hand nets, and a questionnaire survey was conducted with station staff to document washing practices and water use. Results: ANOVA results revealed statistically significant differences (p<0.05) in TDS, EC, salinity, K, and PO₄ between sites. The highest EC (2.2 mS/cm) and salinity (524 mg/L) were observed at Dumiyal, while Nagaral showed elevated CaCO₃ (213 ppm). Macroinvertebrate data indicated the presence of pollution-tolerant Diptera larvae at two sites. Conclusions: Most parameters exceeded WHO recommended limits, indicating ecological degradation and potential health risks. The findings highlight the urgent need for regulation, treatment, and reuse of vehicle wash wastewater. Future studies should assess heavy metal contamination to better understand long-term environmental and public health implications.