Global evaluation of potentially harmful elements (PHEs) in potato and carrot irrigated by wastewater: A systematic review, meta-analysis, and health risk assessment

Background: We aimed to conduct a metaanalysis on the concentration of potentially harmful elements (PHEs) in carrots and potatoes irrigated by wastewater and estimate noncarcinogenic health risks among adult and children consumers. Methods: The health risk of PHEs concentration, including Pb, Cd, total Cr, Ni, Zn, Cu, and Fe, in the edible parts of carrot and potato irrigated by wastewater was investigated by a metaanalysis using a randomeffects model (REM). Accordingly, the related articles were screened from international databases such as Scopus, Medline, and Embase. Results: The metaanalysis of 32 papers (38 studies) revealed that the rank order of the most accumulated PHEs in potato was Fe (86.54 mg/kg wet weight) Zn (30.9 mg/kg wet weight) Cu (13.7 mg/kg wet weight) Ni (8.42 mg/kg wet weight) Pb (5.56 mg/kg wet weight) Cr (3.45 mg/kg wet weight) Cd (0.58 mg/kg wet weight). This ranking for carrot was Fe (43.36 mg/kg wet weight) Zn (36.29 mg/kg wet weight) Ni (13.49 mg/kg wet weight) Cu (9.79 mg/kg wet weight) Pb (1.84 mg/kg wet weight) Cr (1.05 mg/kg wet weight) Cd (0.28 mg/kg wet weight). Total hazard quotient (THQ) of PHEs was higher than 1 for potato and carrot; its rank order for potato and carrot was Cu Pb Cd Ni Fe Zn Cr and Cd Pb Cu Ni Fe Zn Cr, respectively. The Cd, Pb, and Cu had also a considerable role for consumer health risk. Conclusion: According to the results, continuous monitor and control of wastewater treatment plants are necessary.