Quantifying lead (Pb) leaching from galvanized handpump spouts, leaded brass taps, and stainless-steel alternatives using the NSF 61 test protocol: Implications for safe rural water supply

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Abstract
Lead (Pb) is a neurotoxin with no known safe level of exposure. Widespread lead contamination has been reported in rural groundwater-supplied drinking water systems in low- and middle-income countries (LMICs), primarily arising from the corrosion of lead-containing plumbing materials such as galvanized steel and leaded brass. The National Sanitation Foundation (NSF) 372 standard certifies drinking water system components as “lead-free” when the lead content is below 0.25% by weight for wetted surfaces. NSF 61 standard, in contrast, certifies the safety of “endpoint” drinking water system components based on their potential to leach chemical contaminants, including lead. This study evaluates the lead content (NSF 372) and lead leaching behavior (NSF 61) of plumbing components commonly used in LMIC rural community water systems to determine their suitability for delivering safe drinking water. Galvanized borehole handpump tanks (specifically, spouts) and brass taps widely used in Ghana and other LMICs were tested alongside stainless-steel alternatives and lead-free PVC pipe controls against NSF 61 and NSF 372 standards. Stainless-steel components and PVC controls met both standards, whereas galvanized steel spouts and leaded brass taps did not. Average water lead levels leached over the 19-day experimental period were 192 µg/L (SD = 89) for leaded brass taps, 34 µg/L (SD = 3) for galvanized steel spouts, 0.4 µg/L (SD = 0.1) for stainless-steel taps, 0.3 µg/L (SD = 0.3) for PVC pipes, and below the detection limit (0.5 µg/L) for stainless-steel spouts. These findings indicate that lead-containing galvanized steel and leaded brass components that exceed NSF 372 and/or NSF 61 standards pose a significant health risk and should not be used in potable water systems. Lead-free alternatives that meet NSF 372 and NSF 61 standards, such as stainless steel, are strongly recommended for safer rural water infrastructure due to their minimal lead-leaching risk.
Funding Information
  • World Vision (Validation and Prevention of Toxic Metal Contamination of Rural Water Supply Systems in Ghana)

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