Tests conducted on hair samples taken from the heads of schoolchildren in some schools in the the Thessaloniki area have revealed worryingly high traces of arsenic which scientists have linked to high levels of toxic chemicals in local drinking water. The first set of tests carried out by a team of chemists at Thessaloniki’s Aristotle University – to be presented officially at a conference in the northern port city later this week – showed that pupils at 10 out of 32 schools in the region had been drinking water containing high levels of toxic chemicals. The most worrying finding highlighted by scientists was the presence of the potential carcinogenic arsenic, at levels that far exceed the internationally determined safe level of 10 micrograms (mg) per liter, in drinking water at five regional schools. Also of serious concern was the discovery of a toxic compound of the chemical manganese and various nitrates, in concentrations greater than 50 mg per liter, in the drinking water available at eight schools. The second set of tests carried out by the group of scientists focused on the correlation between the toxic chemicals in the water and the chemicals in hair taken from the heads of 65 children, aged 6 to 12, attending local schools. The results of this second set of tests indicated that the concentration of arsenic in drinking water in the area of Halastra, near Thessaloniki, was between twice and 10 times above the recommended safe level of 10 mg/l. «The statistical analysis revealed a positive correlation between the concentration of traces of toxic chemicals in the schoolchildren’s hair and in local drinking water,» the authors of the report said. The report also noted a particularly worrying finding – that the younger children’s hair generally contained a higher concentration of toxic chemicals, suggesting that they had consumed larger amounts of tainted water than the older children. The mayor of Halastra, Grigoris Ouzounis, allegedly disputed the conclusions drawn by the scientists, claiming that children at regional schools drink bottled water, not tap water.