Heavy metal concentrations in drinking water in a country heavily reliant on desalination

Desalination is an important strategy for adapting to the global shortage in safe drinking water. Israel relies heavily on desalinated water (over 50% of supplied drinking water). However, desalinated water may be more corrosive than water from other sources and may cause leaching of heavy metals from materials in contact with water. In this study, we measured heavy metal concentrations (copper, iron, lead) in 1379 drinking water samples in educational institutions in Israel and compared heavy metal concentrations in drinking water from different sources (desalination, groundwater, desalinated and groundwater mixture). 99.9% of the samples met the standard for copper (1400 μg/l), 99.7% for iron (1000 μg/l), and 99.6% for lead (10 μg/l). As expected, heavy metal concentrations were higher in first flush samples compared to flushed samples (significant findings for lead, copper, and iron). Heavy metal concentrations were not higher in desalinated water, or desalinated and groundwater mixture, compared to groundwater. In first flush samples, lead concentrations in groundwater were significantly higher than in desalinated-groundwater mixtures (p = 0.005). In flushed samples, lead concentrations in groundwater were higher than in desalinated-groundwater mixtures but the difference was not significant (p = 0.07). We suggest that regulatory requirements for stabilization of desalinated water and restrictions on lead content of plumbing materials appear to have been effective in preventing increased exposure to lead in desalinated drinking water in Israel. Further study should focus on potential heavy metal leaching in pure desalinated water samples.