Metal compartimentation in different biomass portions of helianthus annuus l. and sorghum bicolor l. grown in an agricultural field inside an urban fabric

Plant-based products comprise the vast majority of human and animal nutrition, and metal concentration and accumulation inside food can affect human health. Recently, agricultural soils are often located in close proximity of urban fabrics and factories, so that risk of contamination is high. A field study was carried out in summer 2014, Aimed at: i) to evaluate the chemical, biological and ecotoxicological characteristics of an agricultural soil in the neighbourhood of the city of Naples (Southern Italy); ii) to detect Cd, Cr, Cu, Ni and Pb concentrations and accumulations in roots iii) to distinguish the potential main pathway (by roots or leaves) of metal uptake in the two crop species. The concentrations of Cd, Cr, Cu, Ni, Pb were measured by atomic absorption spectrometry in soil, roots, stems, leaves and seeds for the two investigated species. The metal bioaccumulation and translocation factors were also calculated. Soils resulted slightly contaminated by Cu and Pb, deriving by both agricultural practices and urban inputs, but did not differ in biological and ecotoxicological characteristics. For both crops, Cu was the most abundant metal and roots appeared the main path of metal uptake, although Cd could be also uptaken by leaves of sunflower from the atmosphere, and metal translocation from roots to the aboveground biomass portions would seem to be traceable. Roots of sunflower apparently excluded Pb from being absorbed. Sunflower, likely for the higher biomass and faster growth rate as compared to sorghum, showed an overall higher metal accumulation, particularly high for Cd and Cu in the seeds.