Assessment of Contaminant Migration in Groundwaterfrom an Industrial Development Area, Medak District,Andhra Pradesh, India

Number of chemical and pharmaceutical industries have been established during 1977 in the PatancheruIndustrial Development Area near Hyderabad city in the Medak district, Andhra Pradesh, India. Thetreated and untreated effluents from the industriesare being discharged in two streams: Nakkavagu and Peddavagu. The Pamulavagu, a tributary of the Nakkavagu alsocarries effluents from the adjacent Bolaram Industrial Development area. The industrial effluents are being discharged into open channels and streams in the area. Groundwater contamination has been reported since 1985.Groundwater level and water quality monitoringwas carried out during 1997 and 1998 in Patancheru andits environs, covering an area of 120 km2. Surface watersamples were also analyzed for the water quality. Thesurface water TDS (Total Dissolved Solids)concentration was found ranging between 3000–5000 mg L-1. The groundwater in the alluvium ofthe Nakkavagu has shown TDS concentrations ranging from1000–3000 mg L-1. The Nakkavagu is acting as adiffuse source of contaminants all along its course. Aquifer parameters were estimated by carrying outpumping tests at a number of wells. Groundwater flowand mass transport models were prepared using visualMODFLOW software. The extent of migration ofcontaminants from the Nakkavagu and other streams has beenassessed for 20 yr (1977–1997). The stream-aquifer interaction was found to be responsiblefor faster migration of contaminants in theover-exploited area east of the Nakkavagu.