Capture and Extraction of Particulate Lead from Point-of-Use Filters

Lead (Pb) in tap water remains a threat to human health. The total lead concentration in tap water is the sum of the concentrations of dissolved and particulate lead. Prior research has described point-of-use (POU) filters as sampling devices to quantify lead in tap water; however, there are questions regarding the effectiveness of this method for particulate lead. The objective of this study was to determine the effectiveness of the extraction method for recovering particulate lead accumulated in POU filters. Four Pb(II) solids and two Pb(IV) solids were loaded onto POU filters separately and in combination. Our results showed that the POU filters effectively removed particulate lead from artificial tap water and that at least 92% of loaded lead solids could be recovered using the same flow-through extraction method developed for dissolved lead. The extraction of Pb(IV) solids was slower than the extraction of Pb(II) solids, but both could be fully extracted in 2 L of acid. Overall, this study demonstrated that POU filters can be used as sampling devices for total lead concentrations in tap water that contains appreciable particulate lead. Moreover, this sampling method has the potential to be extended to other inorganic and organic contaminants in tap water with different extractants.