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