URBAN SOILS AND HUMAN HEALTH

Since the dawn of civilization, the anthropic activity has lead to a legacy of increased land degradation/contamination. Potentially harmful elements (PHEs) are among the most effective environmental contaminants, and their release into the environment is increasing since the last decades. Interest in trace elements has risen as major scientific topic over the last 50 years, when it was realized that some elements were essential to human health (e.g. Fe,Cu,Zn), whereas some others were toxic (e.g. As,Hg,Pb), and likely responsible for serious human diseases and lethal consequences. Since that time, great progresses in knowledge of links between environmental geochemistry and human health have been achieved. The urban environment (nowadays the main habitat for human population) is a potential PHEs source, with high risk for residents'health. Indeed, PHEs concentration and distribution are related to traffic intensity, distance from roads, local topography and heating. Industrial emissions also contribute to the release of toxic elements. Understanding the extent, distribution and fate of PHEs in urban environment is therefore imperative in order to address the sustainable management of urban soils and gardens in relation to human health. Despite the copious research addressed to this topic, the effects of most trace metals on human health are not yet fully understood. Uncertainty is still prevailing, particularly with non-essential elements that are "suspected" to be harmful to humans, causing serious health problems as intoxication, neurological disturbances and also cancer. Some of them (e.g. As,Cd,Hg,Pb) have attracted most attention worldwide, due to their toxicity towards living organisms. Other elements (Al,B,Be,Bi,Co, Cr,Mn,Mo,Ni,Sb,Sn, Tl,V,W) are likely harmful, but may play some beneficial functions not yet well known, and should be more investigated.