Organophosphates are one of the most common pesticides in the world. Among them, one can find malathion that is classified as carcinogenesis, and, as a result, should be appropriately removed since it is highly consumed and possesses a lot of pathogenicity. So far, several processes have been used to remove malathion from aqueous media. The present study investigates its removal by means of Fe3O4 iron oxide nanoparticles. Based on experimental-laboratory studies, using the Response Surface Methodology (RSM), the impact of independent variables such as pH, iron oxide nanoparticle concentration, and contact time on malathion removal efficiency have been investigated. Results show that the pH of the solution is the most important and effective parameter in the process. Optimal conditions of malathion removal based on the appropriate model, obtained from RSM, include 0.4 g/L iron oxide nanoparticles, pH of about 5 (acidic conditions), and contact time of about 1 h with ultraviolet radiation being equal to 82% malathion removal. The process, used in this study, can remove malathion from aqueous solutions according to the so-called conditions, and changing the laboratory conditions can effectively remove it. This process can also be recommended as an economic and scientific method to remove malathion from drinking water.

This is the first report about the presence of pesticide residues in water and sediments from Chacahua-Pastoria Lagoon System in the Oaxaca Coast, Mexico. Organochlorine and organophosphate pesticides were analyzed in water and sediment samples collected during rainy and dry seasons in 2018. The pesticides extraction was carried out by 525.2 EPA and QuEChERS methods for water and sediments samples, respectively. The quantification was done by gas chromatography coupled to electron microcapture (μECD) and flame photometric (FPD) detectors. Univariate and multivariate analysis were carried out to evaluate the distribution patterns, comparing between lagoons, seasons and matrices. The spatial distribution of malathion and organochlorines in water showed the highest values near to adjacent land with some patterns differences. DDT was the most frequent in water and sediments samples, showed the highest concentrations in the Pastoria Lagoon. These results indicate the need to establish a permanent monitoring programs to implement mitigation measures.

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.

We assessed the combined effects of polyethylene microplastic (MP) and malathion (MLT) on the survival of the fiddler crab Minuca ecuadoriensis, and MP tissue bioaccumulation in four treatments following 120 h exposure: T1) Control; T2) MLT 50 mg L⁻¹; T3) MP 200 mg L⁻¹; and T4) MLT (50 mg L⁻¹) + MP (200 mg L⁻¹). The highest mortality (80%) was in T4, followed by T2 (28%) and no mortality was in T3. Higher MP bioaccumulation was observed in T4 (572 items g tissue⁻¹) followed by T3 (70 items g tissue⁻¹). Our findings indicate that the synergistic effect of MLT and MP increased M. ecuadoriensis bioaccumulative capacity and decreases survival. Thus, as MP contamination in aquatic environments is ubiquitous, our study raises a warning on the synergistic effects of MP with other environmental contaminants and serves as a baseline for further studies.

In this study, 30 pesticide residues in 45 fresh-eating cucumber, tomato, and okra fruit samples collected from the Khuzestan province as the main agricultural products in Iran using the QuEChERS extraction method were analyzed. In addition, noncarcinogen and carcinogen health risk assessments were evaluated. Results indicated that 93% of cucumber samples had at least one pesticide, of course, less than the maximum residue limit (MRL). All tomato and okra fruit samples were contaminated by diazinon. All pesticides detected in tomato samples were below national MRL except for thiamethoxam in four samples. In okra fruit samples, all detected diazinon and malathion, but only tebuconazole fungicide exceeded MRL. In addition, the hazard index (HI) was 0.23 and 1.06 in cucumber samples, 0.33 and 1.51 in tomato samples, and 5.5E-03 and 0.025 in okra fruit samples in adults and children, respectively. The use of cucumber and tomato may have notable risks in the short term in children group age. Ranking based on total CR was 1.2E-05 in tomato, 7.7E-06 for cucumber, and in okra 9.1E-11 because of the difenoconazole residue. However, significant carcinogenic risk threatens cucumber and tomato consumers.

The release and accumulation of pesticides in the environment require the development of novel sustainable technologies for their removal. While adsorption is a classical approach, the design of new materials with enhanced adsorption properties could rationalize the remediation routes and decrease potential risks for their non-target organisms, including humans. More importantly, the use of adsorbents and their synthesis should be implemented in a sustainable and environmentally friendly manner. In this contribution, we studied the adsorption of organophosphorus pesticides (OPs) dimethoate, malathion, and chlorpyrifos on viscose fiber–derived activated carbon fibers (ACFs). The most efficient adsorption was found for chlorpyrifos, followed by malathion and dimethoate, while material properties were correlated with OP uptake. These ACFs are extremely efficient for chlorpyrifos adsorption, with experimentally observed adsorption capacitances reaching 240 mg g⁻¹. Detailed analysis suggests that chlorpyrifos is physisorbed on ACF surfaces and that increased surface hydrophilicity reduces the uptake. Studied ACFs have great potential for practical application. They can reduce OPs’ concentrations to such levels that no acute neurotoxic effects of the studied OPs in spiked tap water samples are seen, even for starting concentrations up to 10⁴ times higher than the allowed ones. Finally, this study presents possible guidance for developing even more efficient and environmentally friendly adsorbents for chlorpyrifos, the most toxic among studied OPs.