Leaching of Metal Pollutants from Four Well Casings Used for Ground-Water Monitoring

Polytetrafluoroethylene PTFE, polyvinylchloride PVC, stainless steel 304 SS 304 and stainless steel 316 SS 316 well casings were tested for suitability for ground-water monitoring. A laboratory experiment, testing for the leaching of Ag, As, Ba, Cd, Cr, Hg, Pb, Se and Cu, was run in triplicate by exposing sections of the well casings to ground water for four periods ranging from 1 to 40 days. The results showed that PTFE did not leach any of the nine analytes studied, while SS 316 and PVC showed significant leaching of Cr, Cd and Pb SS 316 also leached significant amounts of Ba and Cu. Stainless steel 304 showed significant leaching of Cr and Pb. In every case where contamination was observed, the release of metal analyte, when averaged over all of the exposure periods, was the greatest from either SS 304 or SS 316. Released contaminants were sorbed back onto the well casings in several cases. Keywords Silver, Arsenic, Barium, Cadmium, Mercury, Lead metal, Selenium, Copper, Water pollution, Pollutants.