LEAD IN DRINKING WATER IN SLOVENE KINDERGARTENS AND PRIMARY SCHOOLS

Objectives: The purpose of the study was to determine lead content in drinking water in older kindergartens and primary schools in Slovenia. It is well-known that exposure to lead in early childhood may cause permanent neurological and psychological changes. Methods: To determine lead concentrations in kindergarten and school drinking water, a sample of 250 ml of drinking water is collected when it has remained stagnant in the pipes for eight to 18 hours. The first-draw sample is taken from a faucet in the kitchen where foods and drinks are prepared. The ICP-MS method was used to determine lead levels in drinking water, colorimeter to measure free chlorine, and MultiLine P4 with a combination electrode SenTix ORP or SenTix 41-3 with integrated temperature sensor to detemine redox potential and pH values. Results: Six of the 39 samples had lead levels higher than 10 mu g/l, three samples had borderline lead concentrations (10 mu g/l); in two samples lead levels notably exceeded borderline values, reaching 42 mu g/l and 26 mu g/l. A moderate negative correlation was found between the level of pH and lead levels in drinking water, a finding corroborating the assumption that increased lead concentrations in water are due to a low pH level. Discussion: The study stresses the problem of elevated lead concentrations in drinking water found in older kindergartens and primary schools. Since all flushed samples contained less than 10 mu g/l of lead, the easiest and most effective way to lower lead levels in drinking water would be flushing all water pipes in the kitchen by letting water run for a few minutes. Lead testing will be repeated in summer when water temperatures may increase by up to 10 degrees C, and lead content in drinking water may double. For the purposes of national drinking water monitoring a new method for determining lead content in drinking water will have to be introduced, i.e. sampling of water that has been sitting in the pipes for at least 8 to 18 hours.