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Результаты 4341-4350 из 6,535
Solubility and reactivity of surfactant-enhanced alkaline hydrolysis of organophosphorus pesticide DNAPL Полный текст
2020
Muff, Jens | MacKinnon, Leah | Durant, Neal D. | Bennedsen, Lars Frausing | Rügge, Kirsten | Bondgaard, Morten | Pennell, Kurt D.
The study presented in this paper evaluated the effectiveness of surfactants in enhancing mass removal of organophosphorus pesticides (OPPs) from soil under highly alkaline conditions and potential for enhancing in situ alkaline hydrolysis for treatment of OPPs, particularly parathion (EP3) and methyl parathion (MP3). In control and surfactant experiments, hydrolysis products EP2 acid, MP2 acid, and PNP were formed in non-stoichiometric amounts indicating instability of these compounds. MP3 and malathion were found to have faster hydrolysis rates than EP3 under the conditions studied. All surfactants evaluated increased solubility of OPPs under alkaline conditions with four nonionic alcohol ethoxylate products providing the greater affect over the polyglucosides, sulfonate, and propionate surfactants evaluated. The alcohol ethoxylates were shown to provide substantial mass removal of OPPs from soil. Hydrolysis rates were typically slower in the presence of surfactant, despite the relatively higher aqueous concentrations of OPPs; this was likely due to micellar solubilization of the OPPs which were therefore less accessible for hydrolysis. The results of this study support the use of surfactants for contaminant mass removal from soil, particularly under alkaline conditions, and may have implications for use of some surfactants in combination with other technologies for treatment of OPPs.
Показать больше [+] Меньше [-]An improved gray Bernoulli model for estimating the relationship between economic growth and pollution emissions Полный текст
2020
Li, Qin | Wang, Zheng-Xin | Zhang, Xiang-Yu
The environmental Kuznets curve (EKC) hypothesis is used to describe the relationship between economic development and environmental pollution. In this paper, an EKC-estimating method based on an improved nonlinear gray Bernoulli model (NGBM) is proposed from the perspective of gray system modeling. First, a non-equigap NGBM is established taking the GDP per capita and pollutant emission as the input and output of the gray system, respectively. Then, a particle swarm optimization algorithm is used to find the parameters in the nonlinear model. Finally, the EKC is validated by applying it to the per capita emission of wastewater, SO₂, CO₂, and soot in China. The results show that the new method proposed in this paper optimizes the exponent of the NGBM which allows it to describe the trends in the different morphological data very well, resulting in a higher fitting accuracy. China’s per capita emission of wastewater, SO₂, CO₂, and soot show trends corresponding to monotonically increasing, inverted U-shaped, S-shaped, and N-shaped changes, respectively.
Показать больше [+] Меньше [-]Oxidative stress and mitochondrial dysfunction in organophosphate pesticide-induced neurotoxicity and its amelioration: a review Полный текст
2020
Farkhondeh, Tahereh | Mehrpour, Omid | Forouzanfar, Fatemeh | Roshanravan, Babak | Samarghandian, Saeed
Organophosphorus pesticides (OPs) are widely used for controlling pests worldwide. The inhibitory effects of these pesticides on acetylcholinesterase lead to neurotoxic damages. The oxidative stress is responsible for several neurological diseases, including Parkinson’s disease, seizure, depression, and Alzheimer’s disease. Strong evidence suggests that dysfunction of mitochondria and oxidative stress are involved in neurological diseases. OPs can disturb the function of mitochondria by inducing oxidative stress. In the present study, we tried to highlight the role of dysfunction of mitochondria and the induction of oxidative stress in the neurotoxicity induced by OPs. Additionally, the amelioration of OP-induced oxidative damage and mitochondrial dysfunctional through the chemical and natural antioxidants have been discussed.
Показать больше [+] Меньше [-]Effect of plant hedgerows on agricultural non-point source pollution: a meta-analysis Полный текст
2020
Zheng, Yonglin | Wang, Haiyan | Qin, Qianqian | Wang, Yige
Eutrophication has been a critical environmental issue due to soil nitrogen (N) and phosphorus (P) loss in runoff from agricultural lands. Plant hedgerow is an important measure to prevent soil erosion and reduce agricultural non-point source pollution (NPSP). In the present study, we searched 3683 research papers on plant hedgerows published from 1980 to March 2020. After screening, we used 53 effective papers on plant hedgerows for the meta-analysis by using Stata 15.1. The results showed that plant hedgerows significantly increased soil organic matter (SOM) (standardized mean difference (SMD) = 1.46; 95% confidence interval (CI) = 1.12–1.80 > 0), total N (TN) (SMD = 1.33; 95% CI 0.98–1.68 > 0), total P (SMD = 0.73; 95% CI 0.26–1.20 > 0), alkali N (SMD = 0.86; 95% CI 0.52–1.21 > 0), available P (SMD = 1.28; 95% CI 0.75–1.81 > 0) and readily available potassium (K) (SMD = 1.20; 95% CI 0.75–1.65 > 0) concentrations but exhibited no significant effects on soil total K concentration (SMD = 0.17; 95% CI − 0.13–0.47 < 0). Plant hedgerows showed a greater effect on SOM increase than soil N, P, and K, and soil TN increase than the available state, but the opposite trend was observed for P and K. This meta-analysis can clarify the influence of plant hedgerows on soil nutrients and provide ideas for the prevention and control of agricultural NPSP.
Показать больше [+] Меньше [-]Novel reduced graphene oxide/ZnBi2O4 hybrid photocatalyst for visible light degradation of 2,4-dichlorophenoxyacetic acid Полный текст
2020
Tho, Nguyen Thi Mai | Khanh, Dang Nguyen Nha | Thang, Nguyen Quoc | Lee, Yong-Ill | Phuong, Nguyen Thi Kim
A new highly efficient rGO/ZnBi₂O₄ hybrid catalyst has been successfully synthesized through oxidation-reduction and co-precipitation methods, followed by heating at 450 °C. The obtained rGO/ZnBi₂O₄ catalyst was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The catalytic activity of rGO/ZnBi₂O₄ under visible light irradiation was tested using 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. The rGO/ZnBi₂O₄ hybrid catalyst containing 2% rGO (2.0rGO/ZnBi₂O₄) showed the best catalytic performance. More than 90% of 2,4-D in a 30 mg/L solution was degraded after 120 min of visible light irradiation using 2.0rGO/ZnBi₂O₄ at 1.0 g/L concentration. Moreover, the 2.0rGO/ZnBi₂O₄ catalyst showed excellent stability over four consecutive cycles, with no significant changes in the photocatalytic degradation rate. This study demonstrated that rGO/ZnBi₂O₄ may be a promising, low-cost, and green photocatalyst for environmental remediation applications.
Показать больше [+] Меньше [-]Impact assessment of Bt maize expressing the Cry1Ab and Cry2Ab protein simultaneously on non-target arthropods Полный текст
2020
Yin, Yue | Xu, Yudi | Cao, Kaili | Qin, Zifang | Zhao, Xinxin | Dong, Xuehui | Shi, Wangpeng
Transgenic maize expressing the Cry1Ab and Cry2Ab protein simultaneously from Bacillus thuringiensis (Bt-maize) has been grown for farm-scale study to investigate its potential impact to non-target arthropod (NTA). The trials were conducted between Bt maize 2A-7 and its parental line (B73-329) in Beijing, China, over 3 years. Richness (C), Shannon index (H), Pielou index (J), Simpson index (D), and Bray-Curtis index were used to evaluate the population dynamics and biodiversity of the dominant arthropods from per 50 plants in crop field. The mainly abundant groups were Aphidoidea, Araneae, Coccinellidae, Anthocoridae, and Thripidae which represented about 90% of the total number of NTA. Although the abundance of NTA varied from year to year, there is no significant difference between Bt maize and non-Bt maize field. Fluctuations were found at individual sample dates, but the trend of these descriptors remained consistent. Further analysis showed the biodiversity indexes of the dominant arthropods C, H, J, D, and Bray-Curtis dissimilarity between Bt maize producing Cry1Ab and Cry2Ab toxin simultaneously and its parental line had no significant difference except for some sampling dates. These results suggested that Bt maize is compatible with the NTAs and provides further evidence of the ecological impact of genetically modified maize.
Показать больше [+] Меньше [-]Ca, Cu, and Li in washed and unwashed specimens of needles, bark, and branches of the blue spruce (Picea pungens) in the city of Ankara Полный текст
2020
Cetin, Mehmet | Sevik, Hakan | Cobanoglu, Oguzhan
The use of certain types of plants to determine the accumulation of HMs (heavy metals) has yielded quite consistent results in the research fields. Many researches have focused on particular types of HMs due to their common presence in the air (Pb, Cd, Ni, Co, Cr to name a few). However, it is equally as important to shed light on other types of HMs and the scale of their existence in our atmosphere, hence this paper. Blue spruce (Picea pungens) tree organs were used in an experiment to calculate the recent concentration of HMs. The research concentrates on Ca, Cu, and Li elements in the washed and unwashed needles, branches, and barks, and these organs were evaluated depending on the organ age. The study results showed that the concentration of the elements subjected to the research changed depending on the organ, washing status and organ age, and that the lowest concentrations of Ca and Cu elements were obtained in the barks in general. In relation to the organ age, it was found that there was an increase in the concentration of Ca with age, and that the concentration of Li element was inversely proportional to age.
Показать больше [+] Меньше [-]Evaluation of bioconcentration and toxicity of five metals in the freshwater rotifer Euchlanis dilatata Ehrenberg, 1832 Полный текст
2020
Hernández Flores, Saraí | Santos Medrano, Gustavo Emilio | Rubio Franchini, Isidoro | Rico Martínez, Roberto
Metals are widely used in modern society harming the environment; their toxicity cause environmental adverse effects to many organisms including zooplankton. This contribution employed: (a) acute and chronic toxicity tests, (b) epifluorescence image analysis, and (c) atomic absorption techniques, to analyze toxicity of four trace (copper, iron, nickel, and zinc), and one non-trace metals (mercury) on the freshwater rotifer Euchlanis dilatata. This work integrated results of Bioconcentration Factors (BCF’s), sites of entry and accumulation and to determine mechanisms of uptake and toxicity of these five metals of the freshwater rotifer Euchlanis dilatata. This integral analysis enhanced our understanding of knowledge on: (a) the toxicity mechanisms, (b) sites of metal entry and concentration inside the rotifer, (c) bioconcentration and body burdens. As expected, Hg the non-trace metal used here, was the most toxic. Our results suggest that the toxicity is ameliorated in the rotifer by selecting feeding avoiding the most toxic particles and reducing adverse effects on reproduction, until mortality per se reduces reproduction. The chronic effect on ingestion rate was quite sensitive for all metals whereas reproduction was slightly affected. The combination of acute and chronic tests and determination of BCF’s for each metal allowed calculation of the acute and chronic body burdens. Body burdens again confirmed that mercury was the most toxic metal of the five employed here.
Показать больше [+] Меньше [-]Occupational exposure to pesticides and associated health effects among greenhouse farm workers Полный текст
2020
Amoatey, Patrick | Al-Mayahi, Ahmed | Omidvarborna, Hamid | Baawain, Mahad Said | Sulaiman, Hameed
The number and production capacities of greenhouse farms have been increased across the globe, driven by an effort for addressing food security problems related to the rapid population growth and the effects of climate change. As a result, there was a large increase in the number of greenhouse farm workers who are typically involved in chemical preparations and pesticide sprayings, crop harvesting, and greenhouse maintenance activities. Considering the enclosed architecture of the greenhouse farm design and the frequent application of pesticides, the objective of this review was to characterize pesticide exposure levels and resultant health effects among greenhouse farm workers. While most health assessment studies were mainly based on self-reported symptoms, this review showed limited epidemiological and clinical studies on the assessment of the health effects of pesticide exposure on greenhouse workers’ health. Reproductive disorders, respiratory symptoms, neurological symptoms, and skin irritations were the most reported health effects among greenhouse farm workers. Additionally, there were limited studies on respirable pesticide-borne fine and ultrafine particulate matters in greenhouse farms. Ventilation systems and indoor environmental conditions of greenhouse farms were not designed according to specifications of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Among recommendations provided, long-term exposure assessments of pesticide effects on children born by greenhouse farm workers should be considered in future research. Also, compliance with ASHRAE indoor ventilation and environmental standards will be very important in reducing pesticide exposure and health effects among greenhouse farm workers.
Показать больше [+] Меньше [-]Radiolytic degradation of chlorobenzene in aerated and deoxygenated aqueous solutions Полный текст
2020
Albarrán, Guadalupe | Mendoza, Edith
Radiation-induced degradation of chlorobenzene was conducted at 0.1, 0.4, 0.5, 0.7, and 1.0 mmol/dm³ concentrations in aerated environment and at 1.0 mmol/dm³ in oxygen-free and N₂O-saturated solutions. The results demonstrated that the elimination of chloride is important when the solution is oxygen free, because the [Formula: see text] attacks at the ipso position of the chloro group produces hydrochloric acid. The degradation was affected to a large extent by the concentration and to a lesser extent by the presence or absence of oxygen in the solutions which were irradiated. Thereby, the degradation occurred faster in the solutions with air and without oxygen and more slowly in the saturated solution with N₂O. Some by-products were identified using an HPLC-UV-mass system. In addition, it was found that there is a linear correlation between the ln C/C₀ and the dose, indicating that the radiolytic degradation followed pseudo-first-order reaction kinetics. The radiolytic oxidation was followed by the chemical oxygen demand (COD) test. The COD decreases when the solute concentration increases. The COD results were for a 0.47 mmol/dm³ of 5.94 mg O₂ dm⁻³ kGy⁻¹ and for 0.09 mmol/dm³ of 7.45 mg O₂ dm⁻³ kGy⁻¹.
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