Blood Lead Levels in Adults and Children of East Otago Communities, New Zealand: Findings From a Public Health Response to Lead Detected in Drinking Water.

Background: In 2020-2021, intermittent elevated lead levels were detected in drinking water from communities of East Otago, New Zealand (NZ). A public health response was initiated with blood lead level (BLL) testing offered to all residents to identify any individuals with elevated levels and to determine if lead-contaminated water caused elevated BLLs in this population. Study Design: Cross-sectional study. Methods: BLL testing was offered to all residents to investigate possible lead exposure. Residents also completed a risk factor survey. Results: The majority of adults and children in the affected area had a BLL test; those with a venepuncture BLL and completed survey (1057 adults and 152 children) were included in the final estimates. The geometric mean (GM) BLL of adults was 1.54 µg/dL (95% confidence interval [CI] 1.49-1.60); children (0-17 years) had a GM BLL of 1.11 µg/dL (95% CI 1.01-1.22). In adults, BLLs increased with age, and children had higher BLLs than young adults. Twenty-nine adults and two children had BLLs exceeding the NZ notifiable threshold of 5 µg/dL. Conclusions: In adults and children aged over 5 years, BLLs were not consistently significantly different from prior national estimates measured in 2014-2016, suggesting that lead detected in the drinking water did not result in elevated BLLs in the exposed population. BLLs in these NZ children and adults were higher than reported in comparable high-income countries, likely due to exposure from known sources such as old paint, remnants of leaded petrol and tapware. NZ requires ongoing public health action to reduce lead exposure.