Irrigation with Treated Municipal Wastewater on Artichoke Crop: Assessment of Soil and Yield Heavy Metal Content and Human Risk

Industrial and municipal wastewaters are often used for irrigating agricultural fields in arid and semi-arid countries, representing the most attractive option to alleviate pressure on fresh-water resources. However, the wastewater may contain various potentially toxic elements and organic matters with highly harmful effects on human and animal health. During two growing seasons of globe artichoke, the effects of irrigation with secondary (SWW) and tertiary (TWW) municipal wastewater on heavy metal soil and plant content were evaluated, together with the consequent human risk from artichoke head consumption. The heavy metal contents (i.e., Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn, and Mn) of the irrigation water, soil, plant, and yield were analyzed. Total and extractable heavy metals were quantified to determine the bioaccumulation factors, and the health risks to adults and children were determined according to hazard indices. The heavy metal contents of the artichoke heads harvested after SWW and TWW irrigation were lower than the international threshold values, and low bioaccumulation factors suggested that these heavy metals did not accumulate in the edible part of the artichoke crop. The hazard indices that were based on the consumption of the artichoke heads remained <1.0 for both adults and children, thus indicating that the health risks involving the different heavy metals are not significant.