Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes最新文献

Sheath blight (Rhizoctonia solani) causes significant yield losses in rice (Oryza sativa L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to R. solani and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to R. solani in vitro. E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of R. solani, followed by spray inoculation of a bacterial suspension (10⁸ CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (Pseudomonas nitroreducens), BRM65929 (Priestia megaterium), and BRM65919 (Bacillus cereus) reduced R. solani colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (Serratia marcescens), BRM65923 and BRM65916 (P. megaterium) and BRM65919 (B. cereus) with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.

The present study examined the effects of mesoporous silica nanoparticles (MSNs) on its adsorption capacity of aflatoxin B₁ (AFB₁). Moreover, the study evaluated the toxicity of MSNs with AFB₁ using NIH3T3 cells and hemolysis test. The obtained MSNs were spherical, irregular-like in shape, having a mean size of 39.97 ± 7.85 nm and a BET surface area of 1195 m²/g. At 0.1 mg mL^-1 concentration of MSN, the AFB₁ adsorption capacity was 30%, which reached 70% when the MSN concentration increased to 2.0 mg mL^-1. Our findings showed that AFB₁ was adsorbed (∼67%) in the first few minutes on being in contact with MSNs, reaching an adsorption capacity of ∼70% after 15 min. Thereafter, the adsorption capacity remained constant in solution, demonstrating that the MSNs adsorbed toxins even beyond overnight. MSN treatment (0.5-2.0 mg mL^-1) using NIH3T3 cells did not result in any reduction in cell viability. In addition, MSN treatment completely reversed the cytotoxic effect of AFB₁ at all concentrations. Hemolysis test also revealed no hemolysis in MSNs evaluated alone and in those combined with AFB₁. To the best of our knowledge, this study is the first to demonstrate that MSN can reduce cell toxicity produced by AFB₁ due to its potential to adsorb mycotoxins.

Aquatic organisms are exposed to chemical pesticides including glyphosate (Sharp 480 SL) and atrazine (Atraforce), two phytocidal molecules used for agriculture purposes in Benin. In this study, we assessed the acute toxicity of these two herbicides with emphasis on their histopathological effects on the liver of catfish Clarias gariepinus. One hundred and eighty juveniles of C. gariepinus (mean length 7.26 ± 0.59 cm and mean weight 5.21 ± 3.22 g) were exposed over 96 h to increasing concentrations of each phytocide. The values of 96 h-LC₅₀ were 6.175 × 10³ and 3.165 ppm, respectively for Sharp 480 SL and Atraforce. This indicates that Sharp 480 SL was nontoxic, while Atraforce displayed a moderate toxicity to C. gariepinus juveniles. During the tests, the behavioral responses (hyperexcitation, lethargy, loss of balance, discoloration of skin, etc.) that usually precede death were observed in exposed fishes, confirming the neurotoxicity of these phytocides. Histological alterations observed in liver of contaminated fishes were regressive changes, such as necrosis, hepatocyte vacuolation, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. These results indicate that exposure to these herbicides had destructive effects on the liver of C. gariepinus.

Chlorpyrifos (CPF) is a widely used organophosphorus pesticide. Increasing evidence has shown that exposure to CPF in early life might induce neurodevelopmental disorders, but the pathogenesis remains uncertain. Synaptic plasticity plays a crucial role in neurodevelopment. This study aimed to investigate the effect of CPF on synaptic plasticity in hippocampal neurons and establish the cellular mechanism underlying these effects. Using CPF-exposed rat and primary hippocampal neurons model, we analyzed the impact of CPF on the synaptic morphology, the expression level of a presynaptic protein, a postsynaptic protein and ionotropic glutamate receptors (iGluRs), as well as the effects on the Wnt/β-catenin pathway. We found that the synapses were shortened, the spines were decreased, and the expression of synaptophysin (Syp), postsynaptic density-95 (PSD-95), GluN1, GluA1 and Wnt7a, as well as active β-catenin in primary hippocampal neurons was decreased. Our study suggests that CPF exposure induced dysregulation of synaptic plasticity in rat hippocampal neurons, which might provide novel information regarding the mechanism of CPF-induced neurodevelopmental disorders.

In this work, vermicompost was prepared with maize stover and cattle dung in ratios of 60:40 (VC₁), 50:50 (VC₂) and 40:60 (VC₃), and the physicochemical properties of the vermicompost were related to the ratio of the raw materials used. The effect of the vermicomposts on the adsorption kinetics, adsorption isotherms and desorption of atrazine were investigated in unamended soil (S) and soil amended with 4% (w/w) of VC₁(S-VC₁), VC₂(S-VC₂) and VC₃(S-VC₃). The total organic carbon (TOC) content of VC₁, VC₂ and VC₃ was 38.46, 37.33 and 34.47%, the HA content was 43.50, 42.22 and 39.28 g/kg, and the HA/FA ratios was 1.47, 0.44 and 0.83, respectively. The adsorption of atrazine on the soil, on the vermicompost and on soils amended with vermicompost followed a pseudo-second-order kinetic model. The Freundlich equation better fitted the adsorption isotherm of atrazine. The vermicomposts enhanced atrazine adsorption and decreased atrazine desorption. Correlation analysis showed that the TOC and HA were significantly positively correlated with K_f, which indicated that TOC and HA of the vermicomposts contributed significantly to the adsorption and desorption of atrazine. This study demonstrated that vermicomposts have great potential in the bioremediation of atrazine pollution and that their role is related to the raw materials used to prepare them.

Euphorbia hirta L. is a weed species that is tolerant to the most used herbicide in agriculture, glyphosate. The anatomical characteristics of plants influence the processes of absorption and translocation of herbicides. The objective of this work was to characterize the anatomy of the aerial vegetative axis (leaves and stem) of E. hirta, to support the establishment of strategies for better control of this species with herbicides. The plants were grown in a greenhouse under controlled conditions. When they reached sizes between 8 and 12 cm, samples of stems and leaves were collected, fixed in FAA 50, and stored in 70% ethanol. Subsequently, the samples were processed following usual light microscopy techniques. In cross-section, the stem of E. hirta has a circular shape. The leaf epidermis is uniseriate composed of isodiametric cells of compact arrangement and with the presence of multicellular trichomes and anthocyanin. As for the morphometric parameters evaluated, the young leaves have a lower thickness in the abaxial epidermis. Based on the anatomical characteristics observed in E. hirta, the main barriers that can act in the absorption of herbicides are the high hairiness and the high content of anthocyanin in the epidermal cells.

Herbicide drift phytotoxicity is a problem in plantation crops due to application failures and unfavorable spray conditions. With the increased use of glyphosate in cacao plantations in Ghana, there are concerns about the effect on cacao growth and productivity from doses that potentially could be expected from drift. The aim of this study was to evaluate the physiological and growth response of young cacao plants exposed to glyphosate. Two field experiments were conducted in randomized blocks, with four replications. Glyphosate was applied at rates 0 to 720 g a.e. ha^-1. Crop injury, shikimate accumulation, chlorophyll content, quantum efficiency of PSІІ (Fv/Fm), height, and stem diameter were evaluated. Increased glyphosate rates increased crop injury and shikimate accumulation and decreased chlorophyll content, quantum efficiency of PSІІ (Fv/Fm), and plant growth. Glyphosate rates 360 g a.e. ha^-1 or higher resulted in >60% foliar injury and more than 10-fold increase in shikimate accumulation. Glyphosate reduced chlorophyll content to <10 and Fv/Fm to <0.35 at the highest rates. Glyphosate rates ≥180 g a.e. ha^-1 reduced height and stem diameter of plants and caused reductions in stand count. Thus, cacao showed sensitivity to glyphosate, and severe injury impaired plant growth.

2,4-D or dicamba can cause injuries and other deleterious effects on non-tolerant soybeans. Thus, the objective was to evaluate the potential for injury of subdoses of 2,4-D or dicamba, in drift simulation, for application in non-tolerant soybeans. Two experiments were carried out, one with 2,4-D and the other with dicamba. The treatments consisted of the application, in post-emergence of non-tolerant soybean, of subdoses 0; 1.35; 2.68; 5.37; 10.72; 21.45 and 42.9 g acid equivalent (ae) ha^-1 2,4-D choline salt or dicamba diglycolamine (DGA) salt. Injury symptoms in plants, plant height and yield were evaluated, and the results were subjected to regression analysis. Polynomial fit was possible for the doses of both herbicides, with deleterious effects on soybean, with reductions in height and yield. The application of 2,4-D ≥ 10.72 g ae ha^-1 was enough to cause injuries greater than 10% in plants, in simulated drift. The application of dicamba ≥1.35 g ae ha^-1 was enough to cause injuries greater than 30% in plants, in simulated drift. For both herbicides, greater potential for injury and reductions in soybean yield were observed for the application of the highest doses (21.45 and 42.9 g ae ha^-1).

The enrichment and adaptation of hyper-thermal compost-derived thermophilic inoculum by repeated batch cultivation (RBC) was conducted by investigating bacterial community. The effects of recycling hyper-thermal inoculum by RBC into co-composting were investigated through evaluating the influences of temperature, pH, moisture, C/N ratio, transformation of nitrogen, composting maturity, humification levels and scanning electron microscopy (SEM). The results showed that RBC enriched the thermophilic bacterial community and nitrogen fixation bacteria of the compost-derived thermophilic inoculum. Simultaneously, recycling the inoculum into co-composting increased the temperature, nitrate nitrogen (NO₃^--N) and Germination index (GI), and improved the transformation of nitrogen and humification levels. Conclusively, recycling hyper-thermal inoculum by RBC into co-composting can improve the degradation process.

Acrylamide (AA) a widely used industrial chemical is also formed during food processing by the Maillard reaction, which makes its exposure to humans almost unavoidable. In this study, we used Schizosaccharomyces pombe as a model organism to investigate AA toxicity (10 or 20 mM concentration) in eukaryotes. In S. pombe, AA delays cell growth causes oxidative stress by enhancement of ROS production and triggers excitement of the antioxidant defence system resulting in the division arrest. Aronia fruit contains a variety of health-promoting substances with considerable antioxidant potential. Therefore, Aronia juice supplementation was tested to evaluate its protective effect against AA-derived perturbations of the organism. Cell treatment with several Aronia juice concentrations ranging from 0 to 2% revealed the best protective effect of 1 or 2% Aronia juice solutions. Both chosen Aronia juice concentrations alleviated AA toxicity through the improvement of the antioxidant cell capacity and metabolic activity by their strong ROS scavenging property. Efficiency of Aronia juice cell protection is dose dependent as the 2% solution led to significantly higher cellular defence compared with 1%. Due to the high similarity of biological processes of S. pombe with higher eukaryotes, the protective effect of Aronia juice against AA toxicity might also apply to higher organisms.