Parameters WHO international standard (1971, 1983) Bore wells exceeding permissible limits Undesirable effect Most desirable Maximum allowable Post-monsoon Pre-monsoon pH 7.0-8.5 9.2 Nil Nil Taste TDS (mg/L) 500 1500 Nil Nil Gastrointestinal irritation TH (mg/L) 100 500 S2,S3,S4,S14 S2,S3,S4,S15 Scale formation Na (mg/L) -- 200 Nil Nil Health hazards Ca (mg/L) 75 200 Nil S2,S15   Scale formation Mg (mg/L) 50 150 Nil S2 Cl (mg/L) 200 600 Nil Nil Salty SO4 (mg/L) 200 400 S2,S12,S13 Nil Laxative

Table 6: Groundwater samples exceeding permissible limits prescribed by WHO (1971,1983) for drinking purposes  and their effect on human system.