Multiple potentially toxic elements in urban gardens from a Brazilian industrialized city

Abstract

Urban agriculture should be promoted as long as the food produced is safe for consumption. Located in the metropolitan region of São Paulo, Brazil, Santo André has intense industrial activities and, more recently, an increasing stimulus for urban gardening. One of the potential risks associated with this activity is the presence of potentially toxic elements (PTEs). In this study, the concentration of PTEs (As, Ba, Cd, Co, Cu, Cr, Ni, Mo, Pb, Sb, Se, V, and Zn) was evaluated in soil (n = 85) and soil amendments (n = 19) in urban gardens in this municipality. Only barium was above regulatory limits in agricultural soil, although enrichment of all elements was observed. A multivariate statistical approach indicated two groups of elements strongly influenced by the petrochemical complex located in the region. However, no carcinogenic or non-carcinogenic risks were observed. Soil amendments were identified as a possible source of contamination for Ba, Zn, and Pb, as well as for pathogenic bacteria. In addition, the occurrence of antimicrobial resistance suggests that some soil management practices are necessary.