Spatial distribution, ecological and health risk assessment of organophosphorus pesticides identified in the water of Naseri artificial wetland, Iran

Agricultural development is inevitable to meet the growing need for food. But along with this development, there are unintended and undesirable consequences for human life and the environment that need, found a solution and corrected. One of the most important adverse consequences of agricultural development is the pollution of surface and groundwater resources, which results from various factors such as soil erosion and improper use of different pesticides. This study aimed to conduct an environmental monitoring program in Naseri wetland to determine the concentrations of organophosphorus pesticides (OPPs) in water samples and also to evaluate the potential risks (ecological and health risk assessment) of these pesticides. The salting-out assisted liquid-liquid extraction method was used to extract pesticides. The residual concentrations of OPPs evaluated by gas chromatography/mass spectrometry (GC/MS). In this study, the ecological risk of OPPs calculated for wetland ecosystem, based on the acute risk quotient (RQi) formula with maximum (RQmax), mean (RQmean), and mixture (RQmix) concentrations of organophosphorus pesticides in the wetland water. Also, to assess the health risk of consuming contaminated fish with organophosphate pesticides, the potential non-carcinogenic and carcinogenic risks were determined by the hazard quotient (Index) (HQ, HI) and incremental lifetime cancer risk (ILCR) indices, respectively. The mean ± SD concentration of OPPs (Chlorpyrifos, Malathion, Ethion, Dichlorvos, Trifluralin and Diazinon) in samples of wetland water ranged from 0.14 ± 0.08 to 0.35 ± 0.12 and 0.054 ± 0.06 to 0.2 ± 0.1 (μg/L) in summer and autumn, respectively. The mean ± SD of OPPs in fish varied from 0.68 ± 0.86 to 3.94 ± 2.7 (μg/kg). Overall, the concentrations of pesticides in all water and fish samples were below the maximum residue limit (30 μg/kg) during the study period, according to the Environmental Protection Agency (EPA) and the World Health Organization (WHO). The results of acute risk quotient were in summer (RQmax = 3.49E-4 to 0.067, RQmean = 5.8E-5 to 0.029, RQmix = 0.139-0.026, 0.018-3.42E-3) and autumn (RQmax = 8E-4 to 0.051, RQmean = 7.74E-6 to 0.018 RQmix = 0.1-0.013, 6E-3- 1.5E-3). The non-carcinogenic and carcinogenic risk indexes due to fish consumption for adults and children were (HQ = 0.026-4.68E-4, HI = 0.041, ILCR = 1.7E-7) and (HQ = 1.85E-3-1.3E-5, HI = 0.041, ILCR = 5.55E-8), respectively. The risk of OPPs was generally low. But cumulative risk (pesticide mixtures), should not be ignored.