Metals in playground soils of São Paulo city, Brazil

São Paulo is a megacity, with a population of over 20 million inhabitants. Soils have an impact on human health in many ways and young children are especially vulnerable. The concentration of As, Ba, Cr and Zn, were determined in surface soil samples from playgrounds of São Paulo public parks by neutron activation analysis. The results obtained in this study indicated concentration levels higher than the values considered as reference values for soils in São Paulo. The concentrations obtained suggest an anthropogenic source and indicate a potential damage to children's wellbeing.