Arsenic and other metal contamination of groundwaters in the industrial area of Thessaloniki, Northern Greece.

In groundwater, used for drinking water supply in the greater industrial area of Thessaloniki, in Northern Greece, concentrations of total arsenic exceeded the WHO provisional guideline value and the EU maximum contaminant level (MCL) of 10 microg/L. The concentration of total arsenic was in the range between 4-130 microg/L, whereas the median value was 36 microg/L and the average concentration 46 microg/L. Nine out of the eleven wells contained total arsenic at concentration higher than 10 microg/L and it should be stressed that 6 of them contain arsenic at concentrations between 10 (new MCL) and 50 microg/L (previous MCL). The examined groundwaters were found to contain elevated concentrations of manganese and phosphate. Arsenic had a positive correlation with the pH, indicating the possible effect of pH on arsenic mobilisation. These findings emerge the problem of contamination from arsenic, since, according to the EU directive 98/83, all drinking water sources within the European Union should have achieved compliance with the new limits by 12/2003, implying that the situation requires urgent remedial action.