BACKGROUND: Various environmental studies have shown that the problem of elevated concentrations of lead in drinking water exists mainly in older buildings, where lead parts are built in the network or the network contains other materials containing lead. Migration of lead into drinking water is also affected by particular characteristics of the drinking water and by stagnation of the water in the pipes. Children are particularly susceptible to increased risk of lead exposure in the environment and adverse effects of lead will manifests at lower concentrations in the blood. The purpose of this work is to contribute starting points for the creation of evidence-based measures to reduce the levels of lead in drinking water, and thus its impact on human health in Slovenia.
METHODS: The author conducted a cross-sectional study in order to assess the status of selected public water supply systems and domestic water supply systems in selected kindergartens and elementary schools on the basis of a questionnaire. The concentration of lead in the drinking water of the selected kindergartens and elementary schools was determined by means of an experimental method in a laboratory. Cold drinking water samples of 250ml that stood in the pipes from 8 to 18 hours were used. A method for determining the migration from different materials was applied. An old lead pipe was used, which had already been installed in the facility, as well as new materials (plastic, copper, galvanized pipes and stainless steel pipes and also brass faucet, chrome angle valve and plastic hose) which had not been used yet. To determine the concentration of lead in the water the method ICP-MS was applied. Then the ecological study followed. Lead exposure for a 6-year- old child was calculated on the basis of assessing the uptake of lead from air, water, food and soil. In the calculation, absorption factors were considered and also worst–case scenario was provided. For the assessment, the model IEUBK was used.
RESULTS: Sampling showed that more than 22 % of samples had levels of lead higher than 10 gl, some of them highly exceeded that level. Positive correlation between the age of a building and the concentration of lead in drinking water confirms the assumption that the concentration of lead in drinking water is higher in old domestic distribution networks. Implementation of lead migration from various types of pipes demonstrated the migration from galvanized pipes in all simulants. The assessment of lead exposure for a 6-year-old child has shown a risk of adverse health effects.
CONCLUSION: All concentrations of lead after flushing the pipes were below the 10 gl, which shows that the most effective and the fastest action to lower the concentrations of lead is flushing the water pipes. For the purposes of the national monitoring of drinking water, it is necessary to apply a better method for determining lead levels in drinking water namely the sampling of water that stood in the pipes at least 8 to 18 hours.