Assessment of Polycyclic Aromatic Hydrocarbons (Pahs) in Water, Soil and Pepper Irrigated with Treated Wastewater

Due to the water shortages in Mediterranean countries, recycled water is being applied for agricultural uses. Potential risks of wastewater use include the presence of several pollutants dangerous for food security such as polycyclic aromatic hydrocarbons (PAHs), organic molecules containing condensed aromatic rings. Pepper plants (Capsicum annuum 'Aifos') were irrigated with treated wastewater from Almeria city (southeast Spain), and groundwater was used as control. Security risks related to PAHs in treated wastewater were not found according to legislation. Concentrations of PAHs in soils irrigated with wastewater (10.39 mu g kg(-1)) and groundwater (11.01 mu g kg(-1)) were significantly less than original soil (28.10 mu g kg(-1)). These differences could be caused by the decrease of PAHs with 3 or 4 rings, which can suffer higher degradation or possible plant uptake. Final concentration in fruits treated with treated wastewater (16.70 mu g kg(-1)) did not show significant differences with those which were treated with groundwater (14.29 mu g kg(-1)). In both cases, the PAHs quantified in higher rates were phenantrene (Phe) and benzo[a]anthracene (BaA); although their threshold levels are not still defined in horticultural crops, Phe and BaA concentrations were much lower than those obtained in other products like smoked food.