A toxic cocktail that includes arsenic, nickel, cadmium and the pesticide DDT have all been detected in the air that is inhaled by the residents of Thessaloniki, according to research by the city’s Aristotle University. Researchers found that the concentration of suspended particles in the air in some parts of the city, particularly in the center and eastern suburbs, was above the permissible limits on up to 80 percent of days each year. The use of DDT has been banned in Europe after being deemed dangerous to public health amid suggestions that it could cause cancer. «The source has to be researched, as it is possible that it has been blown in from across the border or could come from illegal use in parks and gardens across the city,» said chemistry professor Constantina Samara-Constantinou. A potent insecticide, DDT fell into disrepute after the publication of Rachel Carson’s «Silent Spring» just over 40 years ago. The book showed that widespread, indiscriminate use of DDT and related compounds was killing wildlife over vast tracts of North America and Western Europe. No studies ever proved that it also damaged human health, but it was widely believed to do so and was banned. Thessaloniki has a notorious pollution problem, which is largely attributed to the number of vehicles in the city. Statistics suggest that 44 percent of the city’s residents use their cars on a daily basis. Seven percent use taxis, 6 percent use motorcycles and only 27 percent use buses – one of the lowest percentages in the European Union. Thessaloniki does not yet have a metro system but the network is currently under construction and is due to be completed by late 2012. Samara-Constantinou said that the type of air pollution in Thessaloniki is similar to that found in Barcelona. She said that by 2012, every EU city will have to be able to measure each pollutant in the air individually, but many cities, including Thessaloniki, are not in any position to do that at present.