Bioaccumulation of potentially toxic elements in leafy and tuberous vegetables: a comparison based on meta-analysis studies with a cumulative health risk assessment

Seventy seven research papers published from 1986 to 2018 were observed. These papers investigated PTEs (Pb, Cd, Cu, As, Fe, Zn, Ni, and total Cr) in leafy (mint, spinach, coriander, and lettuce) and tuberous (potato, carrot, radish, and onion) vegetables irrigated by wastewater. The studies observed in our paper were conducted in 19 countries. The PTEs concentrations were compared among studies and the human health risk was observed. According to the obtained meta-analysis results, PTEs concentrations (mg/kg) in vegetables were found in the following order Zn (34.216)> Cu (22.581)> Ni (14.056)> Pb (10.173)> Cr (8.308)> Fe(8.130)> As(1.881)> Cd (1.763). Hazard index for children was higher than that for adults and for both groups, the calculated HQ was higher than 1, which indicates that there is a health risk for the consumers. This study provides a comprehensive analysis that demonstrates the urgent necessity for treating PTE pollution in agricultural areas worldwide.