Evaluation of chemical contamination of crops produced in greenhouse by irrigation with reclaimed water.

Using reclaimed water for agricultural irrigation is increasing worldwide to compensate for water scarcity. The aim of this work was to evaluate the uptake of some of the most commonly detected organic contaminants of emerging concern (CECs) and pesticides in regenerated water in a field study. Furthermore, it was studied their distribution and accumulation in the different parts of a crop (soil, plant and fruit). Three crops (cucumber, pepper and melon) were grown under controlled agronomic conditions in a greenhouse. In order to make an accurate evaluation of the process, "regenerated blank water" was spiked with 70 chemicals (including antibiotics, anti-inflammatories, analgesics, anaesthetics, anxiolytics, anticonvulsants, pesticides) at environmental concentrations (∼1 µg/L) and used for continuous crop irrigation. After crop season, the average total concentration of contaminants detected in the soil samples ranged from 132 to 232 µg/kg d.w depending of the crops type. Between 7 and 10 different contaminants were found in the harvested fruits, up to levels of 27.8 µg/kg f.w. cucumber, 12.4 µg/kg f.w. melon and 7.8 µg/kg f.w pepper. In general, cucumber fruit showed higher accumulation levels of contaminants than pepper and melon for most target analytes. The accumulation rates followed the order: root (0.2 %) < stem/leaf (1-4 %) < fruit (1-6 %) < soil (17-30 %). The experimental data obtained in this study were also used to assess the risk associated with the reuse of reclaimed water for crop irrigation as well to identify those contaminants that, due to their physicochemical properties, show higher accumulation rates and environmental impact.