Simultaneous Determination of Zinc, Cadmium, Lead and Copper in Water by Potentiometric Stripping Analysis

Analysis of zinc (In) cadmium (Cd), lead (Pb) and copper (Cu) in drinking and irrigation waters by potentiometric stripping analysis (PSA) is described. The pH and EC of waters were also determined. The results for zinc and copper were compared with those obtained by atomic absorption spectrophotometry (AAS) which indicated a significantly (P<0.01) strong correlation (r = 0.994 and 0.984 for In and Cu). The waters widely varied in pH, EC, In, Cd, Pb and Cu contents. The range values observed were; pH (7.5-8.7), EC (3.2-16.6 urnhos crrr" x100), In (18.2-89.2 ppb) , Cd (0.5-2.9 ppb), Pb (1.3-10.3 ppb) and Cu (9.2-70.2 ppb). Water of river-Kabul contained generally higher levels of heavy metals and lower EC than others. Lowest Pb was in the tubewell water at Nowshera.