Leaching of Dibutyltin from Virgin Polyvinyl Chloride Pipe Material

This study examined the leaching of dibutyltin (DBT) from PVC particles derived from three different types of PVC pipes. Leaching of DBT into artificial freshwater was investigated at pH 6, 7, and 8, using both small (45–125 μm) and large (300–500 μm) particles alone, as well as in the presence of chlorine or chloramine to represent typical secondary disinfectants used in drinking water. Aqueous DBT concentration varied among the three pipes, suggesting that specific PVC formulations may be more amenable to leaching than others. An increase in pH from 6 to 8 was associated with higher DBT concentrations (by up to 100%), and a greater impact was observed for smaller sized particles. The presence of chlorine increased residual DBT by up to 25%, whereas chloramine exhibited a negligible impact. As treated drinking water commonly has a pH of 7–8 and PVC pipe is increasingly being employed for distribution, these findings highlight the need to assess the leaching of DBT under representative conditions.