A novel public health threat – high lead solder in stainless steel rainwater tanks in Tasmania

Abstract

Objective:We identified two water tanks in Tasmania with water lead concentrations exceeding the Australian Drinking Water Guidelines (ADWG) limit; they had been constructed with stainless steel and high‐lead solder from a single manufacturer. An investigation was initiated to identify all tanks constructed by this manufacturer and prevent further exposure to contaminated water. Methods:To identify water tanks we used sales accounts, blood and water lead results from laboratories, and media. We analysed blood and water lead concentration results from laboratories and conducted a nested cohort study of blood lead concentrations in children aged <18 years. Results:We identifed 144 tanks constructed from stainless steel and high lead solder. Median water lead concentrations were significantly higher in the stainless steel tanks (121µg/L) than in the galvanised tanks (1µg/L). Blood lead concentrations ranged from 1 to 26µg/dL (median 5µg/dL); of these, 77% (n=50) were below the then‐recommended health‐related concentration of 10µg/dL. Concentrations in the 15 people (23%) above this limit ranged from 10–26µg/dL, with a median of 14µg/dL. The median blood lead concentration in the nested cohort of children was initially 8.5µg/dL, dropping to 4.5µg/dL after follow‐up. Conclusions:Lead concentrations in the water tanks constructed from stainless steel and high‐lead solder were up to 200 times above the recommended ADWG limits. Implications for public health:This investigation highlights the public health risk posed by use of non‐compliant materials in constructing water tanks.