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Totally found 1636153 items.

  • [期刊] Evaluating national ecological risk of agricultural pesticides from 2004 to 2017 in China
    In recent years, excessive application and loss of pesticides have caused great risks to the aquatic systems, but the spatio-temporal variability in the ecological risk that agricultural pesticides pose to aquatic systems has not been explored at the national scale. In this study, an integrated assessment framework was proposed for the potential ecological risk of surface water caused by agricultural pesticide loss. The spatio-temporal variability in the potential ecological risk caused by agricultural pesticide runoff was evaluated. Based on the results, the total pesticide emissions increased from 165.47 tons in 2004 to 179.77 tons in 2017. Among the three pesticide types, insecticide had the largest application, but its runoff was estimated as the lowest. High-risk areas of insecticide runoff were concentrated in the east, south and central part of China, while the central region of China was identified as a hotspot due to the high and the ever-increasing ecological risk. This study provides an integrated method for potential ecological risk assessment of agricultural pesticide runoff to adjacent water bodies in large-scale regions and the results of the study have direct implications for environmental policies on pesticide management in China and around the world.
  • [期刊] Children's environmental health based on birth cohort studies of Asia (2) – air pollution, pesticides, and heavy metals
    The life style and child raising environment in Asia are quite different compared with Western countries. Besides, the children's environmental threats and difficulties in conducting studies could be different. To address children's environmental health in Asia area, the Birth Cohort Consortium of Asia (BiCCA) was co-established in 2011. We reviewed the mercury, polychlorinated biphenyls, perfluoroalkyl substances, phthalates, and environmental tobacco smoke in pervious based on birth cohort studies in Asia. The aim of this study was to summarize the traditional environmental pollution and the target subjects were also based on the birth cohort in Asia area. Environmental pollutants included air pollutants, pesticides focusing on organochlorine pesticides, diakylphosphates, and pyrethroid, and heavy metals including lead, arsenic, cadmium, manganese, vanadium, and thallium. Fetal growth and pregnancy outcomes, childhood growth and obesity, neurodevelopment and behavioral problems, and allergic disease and immune function were classified to elucidate the children's health effects. In total, 106 studies were selected in this study. The evidences showed air pollution or pesticides may affect growth during infancy or childhood, and associated with neurodevelopmental or behavioral problems. Prenatal exposure to lead or manganese was associated with neurodevelopmental or behavioral problems, while exposure to arsenic or cadmium may influence fetal growth. In addition to the harmonization and international collaboration of birth cohorts in Asia; however, understand the whole picture of exposure scenario and consider more discipline in the research are necessary.
  • [期刊] Recent advances on TiO2-based photocatalysts toward the degradation of pesticides and major organic pollutants from water bodies
    Pesticides and organic waste constitute a group of environmental pollutants that are widely distributed in our environment due to various human activities. Adsorptive removal and photocatalytic degradation of these pollutants from water have emerged as energy and cost-effective technologies. However, advanced oxidation technologies are gaining attention as an effective method for wastewater treatment capable of degrading a diverse spectrum of organic contaminants. Photocatalysis is a promising advanced oxidation technology to alleviate water pollution problems. Titanium dioxide (TiO2) is the most popular photocatalyst due to its low cost, nontoxicity, high oxidizing abilities, and easy immobilization on various surfaces. The current review aims to highlight recent advancements in photocatalytic degradation of pesticides and major organic pollutants using TiO2-based photocatalysts. Indeed, most of the methods, which employed potent catalysts, showed and exhibited successful degradation of the pesticides under various conditions. We believe this topic of research is extremely vital and will continue to grow in recent years, reaching ultimate desirable results and find more applications in different fields of study.
  • [期刊] Ratiometric fluorescence sensor for organophosphorus pesticide detection based on opposite responses of two fluorescence reagents to MnO2 nanosheets
    The detection of organophosphorus pesticides (OPs) has received considerable attention for their great harm to human beings. Herein, a novel ratiometric fluorescence biosensor was constructed for the determination of OPs by using Scopoletin (SC) and Amplex Red (AR) as probe pairs that have opposite responses to MnO₂ nanosheets (MnO₂ NS). MnO₂ NS possess peroxidase-like catalytic activity, which could quench the fluorescence of SC as well as enhance the fluorescence of the non-fluorescent substance AR by oxidation. In the absence of OPs, acetylcholinesterase (AChE) hydrolyzed acetylcholine chloride (ATCh) into choline (TCh) and acetate. TCh led the decomposition of MnO₂ NS to manganese ions (Mn²⁺), increasing signal of SC and decreasing signal of AR. In the presence of OPs, the activity of AChE was inhibited and the decomposition of MnO₂ NS was hindered, therefore the fluorescence intensity of SC was weak and the fluorescence intensity of AR had an obvious increase. Moreover, under the optimal conditions, the ratio of fluorescence intensity response recorded on the AR/SC increases with increasing the concentration of DDVP. The method has wider linear range of 5.0 pg/mL ∼500 ng/mL with a detection limit of 1.6 pg/mL, which is superior to previously reported methods. This strategy has also been applied to a visual observation based on the color change of the solution under UV light.
  • [期刊] Toxicity of herbicides to cyanobacteria and phytoplankton species of the San Francisco Estuary and Sacramento-San Joaquin River Delta, California, USA
    The herbicides glyphosate, imazamox and fluridone are herbicides, with low toxicity towards fish and invertebrates, which are applied to waterways to control invasive aquatic weeds. However, the effects of these herbicides on natural isolates of phytoplankton and cyanobacteria are unknown. Three species of microalgae found in the San Francisco Estuary (SFE)/Sacramento-San Joaquin River Delta (Delta) (Microcystis aeruginosa, Chlamydomonas debaryana, and Thalassiosira pseudonana) were exposed to the three herbicides at a range of concentrations in 96-well plates for 5-8 days. All three algal species were the most sensitive to fluridone, with IC50 of 46.9, 21, and 109 µg L-1 for M. aeruginosa, T. pseudonana and C. debaryana, respectively. Imazamox inhibited M. aeruginosa and T. pseudonana growth at 3.6 × 104 µg L-1 or higher, and inhibited C. debaryana growth at 1.0 × 105 µg L-1 or higher. Glyphosate inhibited growth in all species at ca. 7.0 × 104 µg L-1 or higher. Fluridone was the only herbicide that inhibited the microalgae at environmentally relevant concentrations in this study and susceptibility to the herbicide depended on the species. Thus, the application of fluridone may affect cyanobacteria and phytoplankton community composition in water bodies where it is applied.
  • [期刊] Organochlorine Pesticides in Selected Sewage Sludge in South Africa : Assessment and Method Validation
    The purpose of this study was to determine the concentrations of organochlorine pesticides (OCPs) in sewage sludge from three wastewater treatment plants (WWTPs), with a view to study their contribution to the environmental pollution of the Amathole District in Eastern Cape, South Africa. Analyses were performed by gas chromatography joined with micro electron capture detector (mu ECD). The limits of detection (LODs) of the tested congeners varied from 0.04 ng/g alpha-Lindane (alpha-BHC) to 0.49 ng/g (endosulfan sulfate), and the limits of quantification ranged from 0.22 ng/g (aldrin) to 2.17 ng/g delta-lindane (delta-BHC). Total concentrations of the 17 congeners for different seasons in the sludge ranged from 191 to 947 ng/g dw. For the six predominant congeners, the total highest concentration levels were found in this order dichlorodiphenyl trichloroethane (DDT), dichlorodiphenyl dichloroethane (DDD), alpha-BHC, gamma-BHC, aldrin and endosulphate 1, and with values of 1512, 1330, 1095, 998, 994 and 547 ng/g respectively. For this result the contamination levels of some congeners for South African sludge can be categorized as high compared with European countries, but moderate to lower compared to other countries worldwide. Some congener (alpha-BHC, gamma-BHC, aldrin, endosulphate 1, DDD and DDT) contents in the samples exceeded limits set by the European Commission for 1000 ng/g set for Sigma DDT and 500 ng/g for other pesticide use of sludge in agriculture.
  • [期刊] Adsorption Mechanism of Metalaxyl Pesticide in Pesticide/Heavy Metal Sediment Using Fractional Factorial Design/Fixed Effects Models
    A resolution V 2(10-3) fractional factorial design method was estimated to identify the main effect and second-order effects of pesticides and heavy metals concentrations in a composite contamination system on adsorption of sediment to metalaxyl, combined with a fixed effects model. It was found that contributions of the second-order interaction effects of the pollutant factor concentrations (79%) was dominated in controlling metalaxyl adsorption to sediment in the system than that of the main effect (21%), and the significant synergistic and antagonistic effects to metalaxyl adsorption were 47.93% and 52.07%, respectively, indicating that metalaxyl adsorption was inhibited. Meanwhile, the main effect and second-order effects of the pollutant factor concentrations (36.32% and 63.68%) in the synergies effects and (6.81% and 93.19%) in the antagonistic effects were calculated, showing that more contribution was attributed from the second-order effects of pollutant factor concentrations to metalaxyl adsorption in the combined pesticide and heavy metal system.
  • [期刊] Determining multi-pesticide residues in teas by dispersive solid-phase extraction combined with speed-regulated directly suspended droplet microextraction followed by gas chromatography-tandem mass spectrometry
    In this study, an effective speed-regulated directly suspended droplet microextraction method was developed to condense pesticide residues from teas through dispersive solid-phase extraction prior to analysis by gas chromatography with tandem mass spectrometry. The extractant was intentionally dispersed into the sample solution in the form of globules through high-speed agitation. This procedure increases the contact area between the binary phases and shortens the distribution equilibrium time. The fine globules reassembled by decelerating stirring speed, the extractant could be taken out for gas chromatography with tandem mass spectrometry. Recovery studies were performed under optimized extraction conditions by using matrix blanks fortified with pesticides at three concentrations (10, 50, and 100 mu g/kg). Over 87% of the recoveries for the analytes in four tea matrices were acceptable given their recovery ranges of 70-120% and relative standard deviations of <= 20%. The limits of quantification of most pesticides were lower than 10 mu g/kg and thus satisfied the requirements for maximum residue levels prescribed by the European Community. A total of 38 tea samples from local markets were analyzed by using the proposed method. Results showed that chlorpyrifos was the most frequently detected pesticide in teas. The method is a potential choice for the routine monitoring of pesticide residues in complex matrices.
  • [期刊] Azadirachtin, a natural pesticide with multiple effects
  • [期刊] Assessing washing methods for reduction of pesticide residues in Capia pepper with LC-MS/MS
    The effects of washing treatments on removal rates of some pesticides residues (acetamiprid, chlorpyrifos and formetanate hydrochloride) on pepper were investigated. Method verification was conducted through spiking pepper samples at 0.1, 1.0 and 10.0 × MRL. QuEChERS method produced average recovery of 104.91% with relative standard deviation (RSD) of 13.41%. LOQ values of acetamiprid, chlorpyrifos and formetanate hydrochloride were estimated as 2, 10 and 5 µg/kg, respectively. Capia peppers grown in open fields were sprayed three times with pesticides. Peppers were harvested after 1st, 2nd and 3rd day of the treatments. Then the peppers were subjected to tap water, acetic acid and citric acid washing and ultrasonic cleaning treatments (for 2 and 5 min). Based on three different harvest times and two different washing durations, processing factors (PFs) and reduction rates were calculated for each washing treatment. The residues gradually decreased during washing treatments with increasing process duration. Similarly, a gradual reduction was noted with the progress of harvest times. This in turn corresponded to an increase in PF. Ultrasonic cleaning and citric acid (9%) washing were more effective than the others. Non-systemic pesticides (chlorpyrifos) were more readily removed than the systemic ones (acetamiprid). Similarly, highly soluble pesticides exhibited higher reduction.
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