Transport of trace elements under different seasonal conditions: Effects on the quality of river water in a Mediterranean area

Twenty percent of the water samples had dissolved Pb and total Hg concentrations that exceeded the Italian guidelines for drinking water (>10 μg/L Pb and >1 μg/L Hg). The highest concentrations of these heavy metals were observed at high-flow conditions and they were likely due to the weathering of mine wastes and to uncontrolled urban wastes discharged into the rivers.