Assessing contamination sources and environmental hazards for potentially toxic elements and organic compounds in the soils of a heavily anthropized area: the case study of the Acerra plain (Southern Italy)

Epidemiological and environmental studies demonstrated that the rate of cancer mortality in the Acerra area, better known as "Triangle of Death", and, more in general, in the Neapolitan metropolitan territory are higher than the regional average values. In the "Triangle of Death" the higher rate of mortality has been mostly related to the presence of toxic wastes illegally buried in agricultural areas which have been contaminating soils and groundwater for decades. Thus, collecting a total of 154 samples over an area of about 100 km2, a detailed study was carried out to assess the geochemical-environmental conditions of soils aiming at defining the environmental hazard proceeding from 15 potentially toxic elements (PTEs), 9 polycyclic aromatic hydrocarbons (PAHs) and 14 organochlorine pesticides (OCPs) related with soil contamination. The study was also targeted at discriminating the contamination sources of these pollutants. Results showed that 9 PTEs, 5 PAHs and 6 OCPs are featured by concentrations higher than the guideline values established by the Italian Environmental laws, especially in the proximities of inhabited centers and industrial areas. The contamination source analysis revealed that, as regards the concentrations of chemical elements, they have a dual origin due to both the natural composition of the soils (Co-Fe-V-Tl-Be) and the pressure exerted on the environment by anthropic activities such as vehicular traffic (Pb-Zn-Sb-Sn) and agricultural practices (Cu-P). As far as organic compounds are concerned, the source of hydrocarbons can be mainly attributed to the combustion of biomass (i.e., grass, wood and coal), while for pesticides, although the use of some of them has been prohibited in Italy since the 1980s, it has been found that they are still widely used by local farmers.