Essential and non-essential elements in lettuce produced on a rooftop urban garden in Sao Paulo metropolitan region (Brazil) and assessment of human health risks

This study evaluated the essential and non-essential elements in lettuce cultivated on a rooftop urban garden in the metropolitan region of Sao Paulo. In addition, the human health risks associated with the potentially toxic metals based on the estimated daily intake (EDI), the target hazard quotient (THQ), and the possible sources of heavy metal contamination by multivariate statistical were analyzed. The lettuces contain essential macronutrients such as K, Ca, and Mg. The Cd, Cu, and Pb concentrations did not exceed the Brazilian legislation limit. Ba, Ni, Cr, Co, and Pb presented low levels compared to oral reference dose and they may be associated to vehicles emissions. Both EDI and THQ values suggested minimal risk upon consumption of lettuce. (author)