Assessment of reclaimed agro-wastewater polluted with insecticide residues for irrigation of growing lettuce (Lactuca sativa L) using solar photocatalytic technology

• Published in: Environmental pollution (1987) Vol. 292; no. Pt A; p. 118367
• Main Authors: Aliste, M., Garrido, I., Hernández, V., Flores, P., Hellín, P., Navarro, S., Fenoll, J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2022
• Subjects: Agricultural Irrigation; Agricultural reuse; Decontaminated water; Heterogeneous photocatalysis; Horticultural crops; Insecticides; Lactuca; Pesticide Residues; Pesticides; Technology; Wastewater; Decontaminated water; Agricultural reuse; Heterogeneous photocatalysis; Horticultural crops; Pesticides
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2021.118367

Scientific literature is full of works studying the removal of different pollutants from water through different Advanced Oxidation Processes (AOPs). Many of them only suggest it is reused for agricultural purposes or for small crops in pots. This study is based on the reuse of reclaimed agricultural wastewater contaminated with four insecticides (chlorantraniliprole, imidacloprid, pirimicarb and thiamethoxam) for growing lettuce in field conditions. First, solar photocatalysis with TiO2/Na2S2O8 was used on a pilot plant in a sunny area (Murcia, SE of Spain) as an environmentally friendly technology to remove insecticide residues and their main reaction intermediates from contaminated water. The necessary fluence (H, kJ m−2) to accomplish 90% removal (H90) ranged from 0.12 to 1212 kJ m−2 for pirimicarb and chlorantraniliprole, respectively. Only six (derived from imidacloprid, pirimicarb and thiametoxam) of 18 transformation intermediate products studied were detected in reclaimed water during the photoperiod (2000 kJ m-2 of accumulated UVA radiation) although all of them were totally photodegraded after a fluence of 1250 kJ m-2. Secondly, reclaimed agro-wastewater was used to irrigate two lettuce crops grown under greenhouse conditions and under agricultural field conditions. In no cases, insecticide residues nor their TIPs were noticed above their respective LOQs (limits of quantification) in soil and lettuce samples (between 0.03 and 0.04 μg kg−1 for pirimicarb and 2.49 and 2.23 μg kg−1 for thiamethoxam, respectively) when they were irrigated with reclaimed water, while residues of the four insecticides and some of their intermediates were found in soil and lettuce by the end of cultivation when they were irrigated with non-reclaimed contaminated water. According to the results, this technology can be applied in a sustainable way, mainly in areas with water scarcity and high solar radiation, contributing to water utilisation in drought areas and the use of renewable energy. [Display omitted] •Pesticide removal was done by solar heterogeneous photocatalysis at pilot scale.•Reclaimed water was reused on lettuce crops under greenhouse and field conditions.•Accumulation of pesticides in soil-plant system has been evaluated.•Transformation products in water, soil and lettuce samples have been also monitored.•This technology is a good tool in areas with lack of water and high solar radiation.