Search Results (23)

Prometryn and acetochlor are herbicides used to control weeds in farmlands and other areas. They enter the soil through direct application, residual accumulation in crops, and atmospheric deposition. The pollution of their residues in the environment has attracted people’s attention. Bioremediation is one of the main methods to solve such problems. In this study, the effects of prometryn and acetochlor-degrading strain NM-1 on soil enzymes, soil microbial communities, and physiological indexes of soybean seedlings during soil remediation were studied, and the relationship between them was discussed. The results showed that 81.54% of prometryn (50 mg·L⁻¹) and 89.47% of acetochlor (50 mg·L⁻¹) were degraded within 15 days after NM-1 inoculation in soil. NM-1 positively affected soil enzyme activities and soil microbial communities, and the abundance of beneficial bacteria in soil increased. More importantly, the inoculation of strain NM-1 under prometryn and acetochlor stress significantly increased plant height, root length, root volume, water content, chlorophyll concentration, and root activity of soybean. The results of these studies showed that the NM-1 strain showed significant potential in bioremediation in order to provide technical support for solving the problem of prometryn and acetochlor pollution. Full article

In this study, a halotolerant bacterial strain was isolated and identified. This bacterium was confirmed to efficiently degrade s-triazine herbicides under saline conditions. The optimal conditions for the metabolism and growth of this strain were determined through single-factor tests. Furthermore, the biodegradation pathways of prometryne (the target compound) by this strain were proposed based on the detection of possible degradation intermediates and genome sequencing analysis. Additionally, a possible halotolerance mechanisms of this strain were also revealed through screening halotolerance-related genes in its genome. The results demonstrated that a halotolerant bacterial strain (designated PC), which completely degraded 20.00 mg/L prometryne within 12 h under saline conditions (30.0 g/L NaCl), was isolated and identified as Paenarthrobacter ureafaciens. The optimal conditions for the metabolism and growth of the strain PC were identified as follows: yeast extract as the additional carbon source with the concentration of ≥0.1 g/L, NaCl concentration of ≤30.0 g/L, initial pH of 7.0, temperature of 35.0 °C, and shaking speed of ≥160 rpm. Furthermore, the strain PC demonstrated efficient removal of other s-triazine herbicides, including atrazine, ametryne, simetryne, and cyanazine. The strain PC might degrade prometryne through a series of steps, including demethylthiolation, deisopropylamination, deamination, dealkalation, decarboxylation, etc., relying on the relevant functional genes involved in the degradation of s-triazine compounds. Furthermore, the strain PC might tolerate high salinity through the excessive uptake of K⁺ into cells, intracellular accumulation of compatible solutes, and production of halophilic enzymes. This study is expected to provide a potentially effective halotolerant bacterium for purifying s-triazine pollutants in saline environments. Full article

This study systematically investigated the effect of organic solvent addition on the detection signal intensity of 15 organic pesticides in water using ultra-high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UHPLC–ESI–MS/MS). The analysis of chromatographic peak area ratios in ultrapure water (UPW) versus 30% methanol (MeOH)–UPW showed that the adsorption effects (AEs, mainly from injection vials with weaker polarity) were the main factor influencing the detection intensity of the organic pesticides. The AEs varied with pesticide type and concentration, especially for those with high logK_ow values and longer retention times, such as malathion, triadimefon, prometryn, S–metolachlor, diazinon, and profenofos. Significant differences were observed in the ability of five organic solvents (MeOH, dimethyl sulfoxide, isopropanol, acetonitrile, and acetone) to reduce AEs, with MeOH being the most effective. Optimal solvent ratios were determined to minimize AEs in aqueous solutions. Additionally, plastic injection vials caused greater AEs than glass injection vials, but the addition of organic solvents increased the detection intensity of the analytes for vials of both materials. Density functional theory calculations of the binding energies between pesticides (diazinon, malathion, and S–metolachlor) and vial materials further confirmed the effect of AE on the detection intensity of the analytes. This study showed that the addition of MeOH to real water samples effectively reduced or eliminated the effects of AEs, achieving a good linearity of calibration curves (0.05/0.1–5 μg/L, R² = 0.9853–0.9998), high sensitivity (LOD = 5–32 ng/L), precision (RSD = 1.4–14.5%), and accuracy (average recoveries = 80.6–121.8%). These results provide technical and methodological support for mitigating the effects of AEs on pesticide detection in water using UHPLC–ESI–MS/MS. Full article

To investigate the toxic and environmental effects of prometryn, a laboratory experiment was performed on coexistent fish and algae. The body weight and length of Carassius carassius, Microcystis aeruginosa (M. aeruginosa) densities and water quality were measured continuously for 92 days. It was observed that fish growth was significantly inhibited by prometryn. This can be partly attributed to the adverse effects of prometryn on the antioxidant system of fish; the activities of superoxide dismutase (SOD) and catalase (CAT) in crucian carp were significantly inhibited by prometryn. The growth of M. aeruginosa was greatly inhibited by prometryn (p < 0.05), and the adverse effects of prometryn on M. aeruginosa indirectly impacted water qualities. The body weight and length of Carassius carassius first increased and then tended to be stable with increasing electrical conductivity (EC) values; their quantified relationship was established based on the Gompertz and Logistic equations (R² = 0.920–0.989). Based on the above results, we concluded that the toxic effects of prometryn can impact the antioxidant system of fish and algae which in turn affects their growth performance, and have an indirect impact on water quality. The application of equations made it realizable to obtain a more detailed interpretation of the processes involved in these biological–abiotic interactions. Full article

Industrial hemp (Cannabis sativa) production is complex, with strict regulatory constraints and challenges associated with a lack of labeled pesticides due to its status as a novel crop in the US. Four experiments were conducted in 2020 and 2021 to establish herbicide tolerances for hemp production in the coastal plain of Georgia, USA. Objectives included evaluating hemp response to pretransplant or posttransplant herbicides, determining if planting method influenced herbicide injury from residual preplant applied herbicides, and understanding how plastic mulch may influence hemp flower yields. When applied one day prior to transplanting, maximum hemp crop visual injury was less than 12% compared to the untreated control, with acetochlor, flumioxazin, fomesafen, pendimethalin, and norflurazon while dithiopyr, halosulfuron, isoxaben, and isoxaflutole resulted in greater than 50% injury. Posttransplant applications of S-metolachlor, acetochlor, pendimethalin, and clethodim resulted in less than 15% injury while halosulfuron, metribuzin, trifloxysulfuron, imazethapyr, and prometryn applications resulted in greater than 50% injury to plants. Preplant and posttransplant applied herbicides were found to have little effect on total tetrahydrocannabinol (THC), cannabidiol (CBD), or total cannabinoids in the dry flower after harvest. In a separate experiment, injury from halosulfuron and metribuzin was 52% to 56% less when planted with a mechanical transplanter as compared to the practice of using a transplant wheel to depress a hole in the soil followed by hand transplanting. In the final experiment, hemp dry flower yield in a non-plastic mulched (bareground) system was similar to that in a plastic mulched system. However, early season plant above-ground biomass was less in the plastic mulched system, which may have been due to elevated soil temperatures inhibiting early season growth. Full article

Pesticide residues in soil, especially multiple herbicide residues, cause a series of adverse effects on soil properties and microorganisms. In this work, the degradation of three herbicides and the effect on bacterial communities under combined pollution was investigated. The experimental results showed that the half-lives of acetochlor and prometryn significantly altered under combined exposure (5.02–11.17 d) as compared with those of individual exposure (4.70–6.87 d) in soil, suggesting that there was an antagonistic effect between the degradation of acetochlor and prometryn in soil. No remarkable variation in the degradation rate of atrazine with half-lives of 6.21–6.85 d was observed in different treatments, indicating that the degradation of atrazine was stable. 16S rRNA high-throughput sequencing results showed that the antagonistic effect of acetochlor and prometryn on the degradation rate under combined pollution was related to variation of the Sphingomonas and Nocardioide. Furthermore, the potential metabolic pathways of the three herbicides in soil were proposed and a new metabolite of acetochlor was preliminarily identified. The results of this work provide a guideline for the risk evaluation of combined pollution of the three herbicides with respect to their ecological effects in soil. Full article

In this study, we aimed to identify suitable herbicides for quinoa fields in Anhui Province and explore the value of their potential application in order to achieve the sustainable weed management of the crop and tackle the global issue of unregistered herbicides in quinoa fields. Employing a pre-emergence seed soaking method, we evaluated the effects of different herbicides, such as anilofos, prometryn, pendimethalin, and atrazine on the germination inhibition rate of quinoa seeds, as well as their impacts on the growth indicators of quinoa seedlings. Our findings show that, while these herbicides initially suppressed quinoa seed germination, this effect decreased over time, allowing for the successful germination of all seeds, suggesting the existence of a recovery mechanism in quinoa. An increase in herbicide concentration was correlated with significant decreases in the germination vigor and index of quinoa seeds, along with a decrease in plant height, root length, and fresh weight. Notably, anilofos, prometryn, pendimethalin, and atrazine demonstrated significant inhibitory effects on quinoa seedlings, thus providing critical insights into the sensitivity of quinoa to these chemicals. Greenhouse pot experiments showed that pre-emergence herbicides, such as napropamide, pretilachlor, s-metolachlor, and anilofos, and post-emergence herbicides, including fluroxypyr, penoxsulam, clethodim, quizalofop-P-ethyl, oxaziclomefone, metamifop, benzobicyclon, nicosulfuron, and pinoxaden, are safe for quinoa and suitable for further field trials, broadening the options for integrated weed management strategies. The results of the mixture experiments indicated that penoxsulam and metamifop are safe for quinoa at a ratio of 1:4.6, and their combined activities against dominant weeds in quinoa fields in Anhui Province, such as Digitaria sanguinalis, Cyperus iria, and Amaranthus viridis, were higher than those of single-agent doses, with fresh weight inhibition rates ranging from 66.98% to 92.16% and selectivity indexes ranging from 176.88 to 3282.17. Therefore, this mixture offers a promising approach to enhanced weed control in a sustainable manner. Full article

To investigate the effect of pesticide use on surface water, the concentration and distribution characteristics of 57 pesticides and 3 degradation products were analyzed in the farmland soil and surface water in the Xingkai Lake area, including water from paddy fields, drainages and the Xingkai Lake, in Heilongjiang Province, China. Forty-three pesticides and three degradation products were detected in farmland soil. In dry field (corn and soybean field) soil, the main detected pesticides were atrazine and acetochlor with mean concentrations of 26.09 ng·g⁻¹ and 49.08 ng·g⁻¹, respectively. In paddy field soil, oxadiazon, mefenacet and chlorpyrifos were the main detected pesticides with mean concentrations of 14.32 ng·g⁻¹, 78.60 ng·g⁻¹ and 20.03 ng·g⁻¹, respectively. In the surrounding water, including water from paddy fields, drainages and Xingkai Lake, the total concentrations of contaminants detected in the water samples ranged from 71.19 ng·L⁻¹ to 10,145.76 ng·L⁻¹. Of the three sampling periods, the mean concentration of contaminants in the water exhibited its peak during the vegetative period. In the analysis of the drainage water, the primary pesticides detected were atrazine, acetochlor and buprofezin with mean concentrations of 354.83 ng·L⁻¹, 109.09 ng·L⁻¹ and 254.56 ng·L⁻¹, respectively. Atrazine, simetryn, buprofezin and isoprothiolane were the main pesticides detected in Xingkai Lake water, with the mean concentrations of 222.35 ng·L⁻¹, 112.76 ng·L⁻¹, 301.87 ng·L⁻¹ and 138.02 ng·L⁻¹, respectively. The concentrations of contaminants could be correlated with drainage, Da Xingkai Lake and Xiao Xingkai Lake water (ρ > 0.8) suggested that the source of these contaminants in drainage and Xingkai Lake water could be the same. The maximum potentially affected fraction (PAF) values of atrazine, chlorpyrifos and prometryn were higher than 5% in Xingkai Lake water, resulting in high ecological risks. Full article

Triazine herbicides are commonly used in agriculture to eliminate weeds. However, they can persist in the environment. In this study, we explored a new method for detecting triazine herbicides in aqueous samples. We selected two triazine herbicides, namely, prometryn and ametryn, as model herbicides. To generate magnetic probes, we mixed aqueous Gd³⁺ with aqueous sodium dodecyl sulfate (SDS), which created magnetic probes made of Gd³⁺-SDS micelles. These probes showed a trapping capacity for the model herbicides. Results indicated that the trapping capacities of our magnetic probes for ametryn and prometryn were approximately 466 and 468 nmol mg⁻¹, respectively. The dissociation constants of our probes toward ametryn and prometryn were 2.92 × 10⁻⁵ and 1.27 × 10⁻⁵, respectively. This is the first report that the developed magnetic probes can be used to trap triazine herbicides. For detection, we used carbon fiber ionization mass spectrometry (CFI-MS), which can be used to directly detect semi-volatiles from the samples in the condensed phase. Because of the semi-volatility of triazine herbicides, the herbicides trapped by the magnetic probes can be directly analyzed by CFI-MS without any elution steps. In addition, we also demonstrated the feasibility of using our approach for detecting triazine herbicides in lake water and drinking water. Full article

Prometryn is a methylthio-s-triazine herbicide used to control the growth of annual broadleaf and grass weeds in many cultivated plants. Significant traces of prometryn are documented in the environment, mainly in waters, soil, and plants used for human and domestic consumption. Previous studies have shown that triazine herbicides have carcinogenic potential in humans. However, there is limited information about the effects of prometryn on the cardiac system in the literature, or the mechanisms and signaling pathways underlying any potential cytotoxic effects are not known. It is important to understand the possible effects of exogenous compounds such as prometryn on the heart. To determine the mechanisms and signaling pathways affected by prometryn (185 mg/kg every 48 h for seven days), we performed proteomic profiling of male mice heart with quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) using ten-plex tandem mass tag (TMT) labeling. The data suggest that several major pathways, including energy metabolism, protein degradation, fatty acid metabolism, calcium signaling, and antioxidant defense system were altered in the hearts of prometryn-treated mice. Proteasome and immunoproteasome activity assays and expression levels showed proteasome dysfunction in the hearts of prometryn-treated mice. The results suggest that prometryn induced changes in mitochondrial function and various signaling pathways within the heart, particularly affecting stress-related responses. Full article

There is growing evidence that long-term exposure to prometryn (a widely used herbicide) can induce toxicity in bony fish and shrimp. Our previous study demonstrated its 96 h acute toxicity on the crab Eriocheir sinensis. However, studies on whether longer exposure to prometryn with a lower dose induces toxicity in E. sinensis are scarce. Therefore, we conducted a 20 d exposure experiment to investigate its effects on the hepatopancreas and intestine of E. sinensi. Prometryn reduce the activities of antioxidant enzymes, increase the level of lipid peroxidation and cause oxidative stress. Moreover, long-term exposure resulted in immune and detoxification fatigue, while short-term exposure to prometryn could upregulate the expression of genes related to immunity, inflammation and detoxification. Prometryn altered the morphological structure of the hepatopancreas (swollen lumen) and intestine (shorter intestinal villi, thinner muscle layer and thicker peritrophic membrane). In addition, prometryn changed the species composition of the intestinal flora. In particular, Bacteroidota and Proteobacteria showed a dose-dependent decrease accompanied by a dose-dependent increase in Firmicutes at the phylum level. At the genus level, all exposure groups significantly increased the abundance of Zoogloea and a Firmicutes bacterium ZOR0006, but decreased Shewanella abundance. Interestingly, Pearson correlation analysis indicated a potential association between differential flora and hepatopancreatic disorder. Phenotypic abundance analysis indicated that changes in the gut flora decreased the intestinal organ’s resistance to stress and increased the potential for opportunistic infection. In summary, our research provides new insights into the prevention and defense strategies in response to external adverse environments and contributes to the sustainable development of E. sinensis culture. Full article

The removal of or decrease in pesticide residues in soil has attracted considerable attention, due to the serious pollution of pesticides in soil. The purpose of the study was to explore the adsorption behavior of biochar on pesticides and the impact on the degradation of pesticide residues in soil, providing a basis for the remediation of soil by biochar. Biochars were prepared via pyrolysis of rice straw at a high temperature (300 °C, 400 °C, 500 °C, 600 °C). The individual and competitive adsorption of three triazine herbicides, prometryn, atrazine, and simazine, on biochar was investigated, and the degradation of the herbicide residues in biochar-added soil was determined. The selected herbicides presented similar adsorption characteristics to rice straw biochar, and the amount of herbicides adsorbed increased with higher preparation temperature and the amount of biochar. The rice straw biochar adsorbed the studied herbicides simultaneously, and the adsorption amount decreased as follows: simazine > atrazine > prometryn. The competition adsorption of the selected herbicides on the biochar presented a lower adsorption affinity than that when they are adsorbed individually. The adsorption isotherm was best fitted by the Freundlich model. The half-lives of prometryn, atrazine, and simazine were 9.8~12.6 d, 5.2~8.1 d, and 3.7~5.6 d, respectively. Biochar addition increased the degradation of the evaluated herbicides in soil. The rice straw biochar could be the potential sorbents that can be implemented for the removal of pesticides. Full article

A new multi-residue method using gas chromatography–mass spectrometry electron ionization selective ion monitoring mode (SIM) has been developed for the simultaneous determination of eight 1,3,5-triazine herbicides such as 1,3,5-triazine-2,4-diamine (atrazine), ametryn, prometryn, propazine, terbuthylazine, terbutryn, and simazine simetryn in water and soil samples. Quantification is done using lindane (gamma benzene hexachloride) as an internal standard. A specific Capillary DB-Wax column of 30 m length, 0.32 mm internal diameter, and 0.25 µm film thickness is used for the separation of eight 1,3,5-triazine-2,4-diamine. The method was applied for the determination of residues in groundwater and soil samples. The lowest detection limit by GC-MS-SIM (selective ion monitoring mode) is 0.1 pg/mL. Recovery in water samples is in the range of 93–103%, and in soil samples, 91–102% for different individual compounds. Forty-five groundwater and soil samples were collected in and around Kancheepuram district in Tamilnadu (India), and they were analyzed for the respective residues. A detailed discussion of the GC-MS analysis results has been presented. Full article

The analysis of pesticide residues in aquatic products is challenging due to low residue levels and the complex matrix interference. In this study, we developed a simple, fast method for the trace analysis of 90 pesticides and metabolites in aquatic products. The analytes covered a wide polarity range with log Kow (log octanol-water partition coefficient) ranging from −1.2 to 6.37. Grass carp (Ctenopharyngodon idellus) and prawn (Penaeus chinensis) samples were chosen to validate the quantification method. The samples were extracted by 0.2% formic-acetonitrile, cleaned by solid-phase extraction (PRiME HLB), and analyzed by high performance liquid chromatography−tandem mass spectrometry. The results showed good linearities for the analytes and were observed in the range of 0.05–50 μg/L. The recoveries of the method were within 50.4–118.6%, with the relative standard deviations being lower than 20%. The limits of quantifications (LOQs) of the method were in the range of 0.05–5.0 μg/kg, which were superior to values compared with other research. The developed method was applied to detect pesticide residues in prawn samples from eastern coastal areas of China. Three herbicide residues of diuron, prometryn, and atrazine were detected in prawn samples. The method was sensitive and efficient, which is of significance in expanding the screening scope and improving the quantitative analysis efficiency in aquatic products. Full article

Pesticide residues in aquatic products are of great concern due to the risk of environmental transmission and their extensive use in aquaculture. In our work, a quick screening approach was developed for the qualitative and semi-quantitative screening of 87 pesticide residues in aquatic products. The sample preparation was investigated, including extract solvent, extract methods, buffer salts, lipid removal, cleanup materials and filter membranes for aquatic products. Samples were extracted using a modified QuEChERS procedure, and two clean-up procedures were developed for UHPLC-Q/Orbitrap MS analysis based on the fat content of the aquatic products. The screening detection limits for all studied pesticides were distributed between 1 and 500 μg/kg in the three representative matrices. Seventy-one pesticides could be analyzed with a screening limit between 1 and 25 μg/kg in grass carp and crayfish, sixty-one pesticides could be screened for limits between 1 and 50 μg/kg in crab. The accuracy results showed that recoveries ranged from 50 to 120% for 60, 56 and 52 pesticides at medium-level for grass carp, crayfish and crab, respectively. At high spiking levels, 74, 65 and 59 pesticides were recovered within the range of 50–120% for the three matrices, respectively. The relative standard deviations of most compounds in different matrices were less than 20%. With this method, the local farmed aquatic products were tested for pesticide residues. In these samples, ethoxyquinoline, prometryn and phoxim were frequently detected. The majority of these confirmed compounds did not exceed 2.00 μg/kg. A grass carp with trichlorfon at 4.87 μg/kg and two carps with ethoxyquinoline at 200 µg/kg were detected, indicating the potential dietary risk. Full article