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The Science of the Total Environment Mar 2021The buds and initial flowers of honeysuckle (Lonicera japonica Thunb.) are most widely used in traditional Chinese medicines (TCMs). In recent years, the problem of...
The buds and initial flowers of honeysuckle (Lonicera japonica Thunb.) are most widely used in traditional Chinese medicines (TCMs). In recent years, the problem of pesticide residues in honeysuckle has attracted much attention. This research aimed to study pesticide residual situation of honeysuckle in China and estimate the potential health risks for consumers using the HQ (hazard quotient) and HI (hazard index) methods. A reliable and robust method was established to determine and quantify 137 pesticide residues simultaneously by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for 151 honeysuckle samples from different planting bases in China in 2017 and 2018. Fifty-four pesticides were detected in total, including 10 unauthorized pesticides (chlorpyrifos, fipronil, carbofuran, omethoate, isofenphos-methyl, triazophos, methomyl, dimethoate, methidathion, and methamidophos). One hundred and fifty (99.3%) samples contained at least 1 and up to 31 pesticides and/or their metabolites, with concentrations ranging from 0.001 to 3.087 mg/kg. Carbendazim, chlorbenzuron, imidacloprid, chlorpyrifos, and acetamiprid were the most frequently detected pesticides in 2017 and 2018, and the corresponding detection rates were 95.31%, 64.06%, 65.63%, 53.13%, 57.81%, and 98.85%, 88.51%, 70.11%, 77.01%, 57.47%, respectively. The acute hazard quotient (HQ) of carbofuran was 1.54 for specific population (fetus, infants, and pregnant or nursing women), which indicated that it posed a potential acute health risk. In the cumulative risk assessment, the acute hazard index (HI) of insecticides in honesuckle for children and the specific population were 1.34 and 3.36, respectively, suggesting that they posed potential acute cumulative health risks. These results were of theoretical and practical value for evaluating the safety of honeysuckle and improving its quality and safety.
Topics: Child; China; Food Contamination; Humans; Lonicera; Pesticide Residues; Risk Assessment; Tandem Mass Spectrometry
PubMed: 33121779
DOI: 10.1016/j.scitotenv.2020.142747 -
Chemosphere Dec 2020Triazophos (TAP), methamidophos (MAP) and carbofuran (CF) pesticides are highly toxic, soluble and absorbable. Efficient co-degradation of multi-pesticides is rare...
Simultaneous degradation of triazophos, methamidophos and carbofuran pesticides in wastewater using an Enterobacter bacterial bioreactor and analysis of toxicity and biosafety.
Triazophos (TAP), methamidophos (MAP) and carbofuran (CF) pesticides are highly toxic, soluble and absorbable. Efficient co-degradation of multi-pesticides is rare reported. The objectives of this study were to investigate TAP, MAP and CF co-degradative ability of Enterobacter sp. Z1 and study the degradation mechanisms. Strain Z1 was shown to efficiently co-degrade TAP, MAP and CF when they were used as primary carbon sources. The degradation occurred over a wide range of temperatures, pH values and pesticide concentrations and followed first-order kinetics. Under the optimum conditions (37 °C, pH 7 and 100 mg/L of each pesticide), the degradation efficiencies were 100%, 100%, and 95.3% for TAP, MAP and CF, respectively. In addition, strain Z1 could simultaneously degrade TAP, MAP, CF and total nitrogen in wastewater in a batch bioreactor, with high removal efficiencies of 98.3%, 100%, 98.7% and 100%, respectively. Genomics, proteomics, qRT-PCR and gene overexpression analyses revealed that the degradation mechanisms involved the activities of multiple proteins, among which, organophosphorus hydrolase (Oph) and 3-hydroxyacyl-CoA dehydrogenase (PaaC) are primarily responsible for TAP and MAP degradation, while carbofuran hydrolase (Mcd) and amidohydrolase (RamA) primarily degrade CF. Among these enzymes, PaaC and RamA are newly identified pesticide-degrading enzymes. Toxicity assays of strain Z1 using reporter recombinase gene (recA) and zebrafish showed that there was no accumulation of toxic metabolites during the degradation process. Biosafety test using zebrafish showed that the strain was nontoxic toward zebrafish. Strain Z1 provides a good purification effect for pesticides-containing wastewater and novel microbial pesticide-degrading mechanisms were discovered.
Topics: Biodegradation, Environmental; Bioreactors; Carbofuran; Containment of Biohazards; Enterobacter; Hydrolases; Organothiophosphates; Organothiophosphorus Compounds; Pesticides; Triazoles; Wastewater; Water Pollutants, Chemical; Water Purification
PubMed: 33113645
DOI: 10.1016/j.chemosphere.2020.128054 -
Frontiers in Microbiology 2020Acephate is an organophosphate pesticide that has been widely used to control insect pests in agricultural fields for decades. However, its use has been partially... (Review)
Review
Acephate is an organophosphate pesticide that has been widely used to control insect pests in agricultural fields for decades. However, its use has been partially restricted in many countries due to its toxic intermediate product methamidophos. Long term exposure to acephate and methamidophos in non-target organisms results in severe poisonous effects, which has raised public concern and demand for the removal of these pollutants from the environment. In this paper, the toxicological effects of acephate and/or methamidophos on aquatic and land animals, including humans are reviewed, as these effects promote the necessity of removing acephate from the environment. Physicochemical degradation mechanisms of acephate and/or methamidophos are explored and explained, such as photo-Fenton, ultraviolet/titanium dioxide (UV/TiO) photocatalysis, and ultrasonic ozonation. Compared with physicochemical methods, the microbial degradation of acephate and methamidophos is emerging as an eco-friendly method that can be used for large-scale treatment. In recent years, microorganisms capable of degrading methamidophos or acephate have been isolated, including sp., , , , and Enzymes related to acephate and/or methamidophos biodegradation include phosphotriesterase, paraoxonase 1, and carboxylesterase. Furthermore, several genes encoding organophosphorus degrading enzymes have been identified, such as , , and . However, few reviews have focused on the biochemical pathways and molecular mechanisms of acephate and methamidophos. In this review, the mechanisms and degradation pathways of acephate and methamidophos are summarized in order to provide a new way of thinking for the study of the degradation of acephate and methamidophos.
PubMed: 33013750
DOI: 10.3389/fmicb.2020.02045 -
World Journal of Microbiology &... Sep 2020Acephate is widely used in agriculture, but its poisonous metabolites and poor sorption characteristics make it a serious environmental pollutant and toxicant to human...
Acephate is widely used in agriculture, but its poisonous metabolites and poor sorption characteristics make it a serious environmental pollutant and toxicant to human health. To screen novel bacteria for biodegradation of acephate and uncover its degradation pathway, a strain called NDZ that is capable of utilizing acephate as a sole carbon and energy source was isolated from severely contaminated cultivated land. The bacterium was identified as Bacillus paramycoides based on 16S rDNA sequence analyses. The growth and degradation capacities of B. paramycoides NDZ under different conditions were studied using optical density at 600 nm (OD) and high-performance liquid chromatography (HPLC). The results showed that B. paramycoides NDZ can grow well with acephate as its sole carbon source (OD = 0.76), and degraded about 76% of acephate in mineral salt medium with an initial concentration of 500 mg/L within 48 h. The results of response surface methodology revealed the optimal conditions for degradation was 36 ℃ and pH 6.85 with 526 mg/L acephate. Gas chromatography-mass spectrometry showed that methamidophos was the main metabolite of B. paramycoides NDZ, different from the degradation products of high-temperature steam (121 °C, 103 kPa). Based on the detection of this intermediate, we inferred that acephate was degraded to methamidophos through hydrolysis of the amide linkage, after which methamidophos was degraded to some small molecules, which can be metabolized easily by the bacterium. In summary, B. paramycoides NDZ is a potentially useful bacterium for acephate degradation and remediation of contaminated soils.
Topics: Bacillus; Biodegradation, Environmental; DNA, Bacterial; DNA, Ribosomal; Gas Chromatography-Mass Spectrometry; Hydrolysis; Metabolomics; Organothiophosphorus Compounds; Phosphoramides; RNA, Ribosomal, 16S; Soil Microbiology
PubMed: 32951077
DOI: 10.1007/s11274-020-02931-1 -
The Science of the Total Environment Nov 2020During water years (WY) 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network - Rivers and...
During water years (WY) 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network - Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic and acute toxicity to three taxonomic groups - fish, cladocerans, and benthic invertebrates. For invertebrates (either cladocerans, benthic invertebrates, or both), the maximum PTI score exceeded the predicted acute toxicity screening level at 18 of the 72 sites (25%) at some point during WY 2013-2017. The predicted toxicity of a single pesticide compound was found to overwhelm the toxicity of other pesticides in the mixtures after concentrations were toxicity weighted. For this study, about 71%, 72%, and 92% of the Fish-, Cladoceran-, and Benthic Invertebrate-PTI scores, respectively, had one pesticide compound primarily contributing to sample potential toxicity (>50%). There were 17 (13 insecticides, 2 herbicides, 1 fungicide, and 1 synergist) of the 221 pesticide compounds analyzed that were the primary drivers of potential toxicity in each water sample in which the PTI and TUmax (toxic unit score for the pesticide that makes the single largest contribution to the PTI) scores were above predicted chronic (>0.1) or acute (>1) toxicity levels for one of the three taxa. For cladocerans and benthic invertebrates, the drivers of predicted chronic (>0.1) and acute (>1) PTIs were mostly insecticides. For cladocerans, the pesticide compounds driving the PTI scores were bifenthrin, carbaryl, chlorpyrifos, diazinon, dichlorvos, dicrotophos, diflubenzuron, flubendiamide, and tebupirimfos. For benthic invertebrates, atrazine (an herbicide), as well as the insecticides - bifenthrin, carbaryl, carbofuran, chlorpyrifos, diazinon, dichlorvos, fipronil, imidacloprid, and methamidophos - were the drivers of predicted toxicity. For fish, there were three pesticide types that contributed the most to predicted chronic (>0.1) PTIs - acetochlor, an herbicide; carbendazim, a fungicide degradate; and piperonylbutoxide, a synergist.
Topics: Animals; Environmental Monitoring; Pesticides; Rivers; United States; Water; Water Pollutants, Chemical
PubMed: 32943215
DOI: 10.1016/j.scitotenv.2020.141285 -
The Science of the Total Environment Sep 2020The release of contaminants of emerging concern (CECs) into water bodies has aroused wide concern in recent years. Little information on the characteristics of CECs to...
The release of contaminants of emerging concern (CECs) into water bodies has aroused wide concern in recent years. Little information on the characteristics of CECs to pose potential risks even at low concentrations in urban water systems of Shanghai is available. This study investigated the occurrence and spatial distribution in source water, as well as the fates by drinking water treatment processes for organic compounds including 35 pesticides, 17 antibiotics, 7 microcystins (MCs), and 10 disinfection by-products (DBPs). The similar trends across seasons for COD and TOC, the indicators for organic pollutants, indicated that the water qualities in three targeted reservoirs were relatively stable. COD in the R3 reservoir inlet was 1.3-2.4 times greater than that in the R1 and R2 reservoirs, possibly resulting from the inflow of the Taipu River as a tributary. Pesticides, particularly methamidophos and metabolites, macrolide and sulfonamide antibiotics, particularly roxithromycin, were frequently detected in Shanghai source water inlets. Pesticide concentrations were 2.58-3.66 μg/L much higher than antibiotics (8.6-47.6 ng/L). The results showed that MCs (ng/L) and DBPs (haloacetic acids, HAAs μg/L; N-nitrosodimethylamine, NDMA ng/L) were found to be in low detection frequencies. It was found that 51.1-74.6% of organic matters in source water were composed of molecular weight (MW) <1 kDa. The removal rates for the part of MW <1 kDa were only 11.7-12.3% through the conventional treatment processes, compared with higher removal rates of 23.5-28.5% by advanced treatment processes. Pesticides, antibiotics and MCs can be significantly removed by six drinking water treatment plants.
Topics: China; Disinfectants; Disinfection; Drinking Water; Water Pollutants, Chemical; Water Purification
PubMed: 32446067
DOI: 10.1016/j.scitotenv.2020.139277 -
Food Additives & Contaminants. Part A,... Aug 2020To assess the dietary exposure risks of pesticide residues in snow fungus for the general population and young children, 91 snow fungus samples were collected from major...
To assess the dietary exposure risks of pesticide residues in snow fungus for the general population and young children, 91 snow fungus samples were collected from major production areas in Fujian Province, China and the presence of 44 pesticides was determined. A total of thirteen pesticides were detected; 65.9% of the samples contained one or more pesticide residues. The most frequently found pesticide was carbofuran, followed by acetamiprid and then imidacloprid. Data obtained were used for chronic, acute, and chronic cumulative dietary exposure risk assessments. The chronic hazard quotient (cHQ) was extremely low for both the general population and young children. The values of cumulative dietary exposures to organophosphorus pesticides and carbamates ranged from 0.53% to 1.49%, and did not exceed their corresponding ADIs. However, the acute dietary risks from all 13 pesticides, especially carbofuran and methamidophos, were of concern due to the relatively high acute hazard quotient. The risk ranking scheme showed that carbofuran could pose a high risk to snow fungus consumers. Finally, suggestions are made about the potential use in snow fungus cultivation of the pesticides with detected residues.
Topics: Basidiomycota; China; Dietary Exposure; Food Analysis; Food Contamination; Humans; Pesticide Residues; Risk Assessment
PubMed: 32429748
DOI: 10.1080/19440049.2020.1766119 -
Reproductive Biology Sep 2020Methamidophos (MET) is a pesticide that has toxic properties, including effects on fertility. This study aimed to assess the joint action of treatment time and exposure...
Methamidophos (MET) is a pesticide that has toxic properties, including effects on fertility. This study aimed to assess the joint action of treatment time and exposure to methamidophos on the male reproductive system. MET was orally administered to adult male Swiss mice at a dose of 0.004 mg.kg for 15 and 50 consecutive days. The following parameters were evaluated: weight of reproductive organs, spermatogenesis, sperm and Sertoli cell count, daily sperm production and sperm transit time. Short-term exposure to methamidophos induced a decrease in epididymal weight. The frequency of stages V-VI of spermatogenesis increased and the frequency of stage IX decreased. In the epididymis, sperm transit time (caput/corpus) was reduced and the relative sperm number (cauda) increased. Long-term exposure induced an increase in the frequencies of stages I-IV and V-VI and decreased the stages VII-VIII and IX. The number of Sertoli cells with evident nucleoli was reduced in both exposures. These results confirm the reproductive toxicity of MET.
Topics: Animals; Epididymis; Insecticides; Male; Mice; Organ Size; Organothiophosphorus Compounds; Reproduction; Sertoli Cells; Sperm Count; Spermatogenesis; Spermatozoa; Testis
PubMed: 32405287
DOI: 10.1016/j.repbio.2020.05.003 -
Environmental Toxicology and Chemistry Jul 2020Singular use of activity assays or staining dyes to assess pathogen agrochemical tolerance can underestimate tolerance if pesticides cause sublethal effects. We exposed...
Singular use of activity assays or staining dyes to assess pathogen agrochemical tolerance can underestimate tolerance if pesticides cause sublethal effects. We exposed Schistosoma mansoni cercariae, the aquatic life stage of this trematode that infects humans, to 4 insecticides at 5 concentrations using a 24-h time-to-death assay. We used Trypan blue dye, which stains dead tissue, and activity assays simultaneously to discriminate dead from live but paralyzed individuals. Whereas cypermethrin, deltamethrin, and dimethoate exposure did not affect cercariae at any ecologically relevant concentrations, methamidophos exposure increased survival of cercariae compared with those in the controls. This was because methamidophos-induced paralysis reduced cercarial activity and thus energy expenditures, extending the lifespan of this short-lived parasite that causes human schistosomiasis. These findings highlight that sublethal effects should be considered when pesticide effects on disease are under investigation. Environ Toxicol Chem 2020;39:1421-1428. © 2020 SETAC.
Topics: Agrochemicals; Animals; Dimethoate; Organothiophosphorus Compounds; Proportional Hazards Models; Schistosoma mansoni; Survival Analysis
PubMed: 32335939
DOI: 10.1002/etc.4732 -
Biomolecules Mar 2020Many bacteria have the potential to use specific pesticides as a source of carbon, phosphorous, nitrogen and sulphur. Acephate degradation by microbes is considered to...
Many bacteria have the potential to use specific pesticides as a source of carbon, phosphorous, nitrogen and sulphur. Acephate degradation by microbes is considered to be a safe and effective method. The overall aim of the present study was to identify acephate biodegrading microorganisms and to investigate the degradation rates of acephate under the stress of humic acid and most common metal ions Fe(III) and copper Cu(II). s strain ACP1 strain ACP2, and ACP3 were isolated from acephate contaminated soils. Acephate of concentration 100 ppm was incubated with separate strain inoculums and periodic samples were drawn for UV-visible, FTIR (Fourier-transform infrared spectroscopy) and MS (Mass Spectrometry) analysis. Methamidophos, S-methyl O-hydrogen phosphorothioamidate, phosphenothioic S-acid, and phosphenamide were the major metabolites formed during the degradation of acephate. The rate of degradation was applied using pseudo-first-order kinetics to calculate the half-life (t) values, which were 14.33-16.72 d (strain(s) + acephate), 18.81-21.50 d (strain(s) + acephate + Cu(II)), 20.06 -23.15 d (strain(s) + acephate + Fe(II)), and 15.05-17.70 d (strains + acephate + HA). The biodegradation efficiency of the three bacterial strains can be ordered as > > . The present study illustrated the decomposition mechanism of acephate under different conditions, and the same may be applied to the removal of other xenobiotic compounds.
Topics: Biodegradation, Environmental; Copper; Humic Substances; Iron; Organothiophosphorus Compounds; Phosphoramides; Pseudomonas; Soil; Soil Microbiology
PubMed: 32168777
DOI: 10.3390/biom10030433