Determination of organophosphorus pesticides in peanut oil by dispersive solid phase extraction gas chromatography-mass spectrometry

The organophosphorus pesticides including phorate, diazinon, tolclofos-methyl, fenitrothin, malathion, fenthion, isocarbophos, quinalphos and phenamiphos, in peanut oils were determined by liquid-liquid extraction coupled with dispersive solid phase extraction and gas chromatography-mass spectrometry (GC-MS). The mixture of multi-walled carbon nanotubes and alumina was used as adsorbent in dispersive solid phase extraction. The effects of some experimental conditions, such as types of multi-walled carbon nanotubes, amount of adsorbents and extraction time were examined. The limits of detection for the analytes were between 0.7 and 1.6 μg kg(-1). The obtained recoveries of the analytes in the samples were between 85.9 and 114.3% and relative standard deviations were lower than 8.48%.     

Determination of organophosphate and carbamate pesticides in spiked samples of tap water and fruit juices by a biosensor with photothermal detection.

The determination of organophosphate (paraoxon, chlorpyrifos, diazinon) and carbamate (carbaryl, carbofuran) pesticides in spiked drinking water and fruit juices was carried out using a photothermal biosensor. The biosensor consists of a cartridge containing immobilised enzyme acetylcholinesterase (AChE) placed in a flow-injection analysis (FIA) manifold and a photothermal detector based on thermal lens spectrometry. With this approach, 0.2 ng/ml of paraoxon can be detected in less than 15 min. Limits of detection for other organophosphate (chlorpyrifos, diazinon) and carbamate (carbaryl, carbofuran) pesticides varied, depending on their antiacetylcholinesterase (AntiAChE) toxicity, from 1 ng/ml to 4 microg/ml. The biosensor was used for the direct detection of pesticides in spiked tap water and fruit juices without any pretreatment steps. In these cases, the LOD3sigma of 1.5, 2.8 and 4 ng/ml paraoxon in tap water, orange juice and apple juice were obtained, respectively.     

In vitro effects of organophosphate pesticides on rat erythrocytes

In vitro effects of various organophosphate pesticides (dimethoate, chlorpyrifos, ethion and monocrotophos) were studied on hemolysis, K+ leakage and lipid peroxidation in rat erythrocytes. All the four pesticides increased hemolysis and K+ leakage from erythrocytes, that was concentration and time dependent. On the contrary, there was decrease in lipid peroxidation in erythrocyte membrane. Effect of pesticides on lipid peroxidation could be due to pesticide itself abstracting protons or interacting with free radicals rather than polyunsaturated fatty acids (PUFA), thereby protecting the latter against peroxidation.     

Human health risk assessment of organophosphorus pesticides in maize (Zea mays L.) from Yushu,Northeast China

In order to investigate organophosphorus pesticides (OPs) concentrations in maize and estimate the health risk to consumers, a total of 55 samples were collected from Yushu, one of the most important maize production areas. The concentrations of the eleven detected OPs in maize were analyzed by gas chromatography coupled with flame photometric detector (GC-FPD). The results showed that OPs concentrations of all maize were not higher than maximum residue limit (MRL), 67.3% of samples below MRL and only in 32.7% of samples was not found OPs. The mean concentrations obtained for the eleven OPs in μg kg^-1 were as follows: omethoate (0.8), quinalphos (0.8), phorate (0.7), dimethoate (0.7), parathion-methyl (0.6), isocarbophos (0.6), diazinon (0.5), fenitrothion (0.5), and malathion (0.5), with parathion (0.5) and fenthion (0.3). Phorate (16.4%), dimethoate (16.4%) and quinalphos (16.4%) had the highest frequency in the eleven OPs. 29.1% samples contained two or more kinds of OPs, while 38.2% samples detected one kind of OPs. The target hazard quotients (THQ) values were all less than one and the total acute hazard index (aHI) values for adults and children were 0.051 and 0.121, respectively indicating that consumer may not pose significant chronic and acute health risk through maize.     

Concentrations of organophosphorus pesticides in rice (Oryza sativa) and human health risk assessment from Songhua River,Northeast China

The aim of this study was to investigate organophosphorus pesticides (OPs) concentrations in rice grains and estimate potential health risk to inhabitants. A total of 102 rice samples were collected from the Irrigated Area of Songhua River, located in Jilin province, one of the most important rice production areas and a key agricultural area in China. The twelve OPs were determined by gas chromatography coupled with flame photometric detector. Results showed that OPs concentrations in rice grains did not exceed maximum residue limit. The mean concentrations obtained for the detected twelve OPs in µg kg^?1 were as follows: omethoate (0.60), diazinon (0.56), parathion-methyl (0.54), dimethoate (0.38), isocarbophos (0.38), phorate (0.31), fenitrothion (0.24), parathion (0.23), fenthion (0.23), malathion (0.13), dichlorvos (0.13), and methamidophos (0.08). Diazinon (39.2%), omethoate (31.4%), and parathion-methyl (25.5%) had the highest frequency in the detected twelve OPs. 69.6% of samples contained more than one OP, 24.5% of samples detected one OP, and only 5.9% samples did not find any OPs. The average target hazard quotients were all less than one and average hazard index for adults and children were 0.273 and 0.238, respectively. Overall, results indicated that the intake of rice may be safe for consumers.     

The use of commercial enzymes in white grape juice clarification

A commercial pectinase from Aspergillus niger containing various polysaccharases clarified the white grape juice to an extent of 98–99% and also degraded the grape mash by 25–30%. This was achieved by optimising the grape mash treatment with 0.048% of enzyme at 27–30°C for 30 min without changing the mash pH. After pectinolytic juice clarification, both juice viscosity and total phenols were reduced by 25% and 32% respectively.     

Pesticide poisoning events in wild birds in Korea from 1998 to 2002

We describe cases of pesticide poisoning of wild birds diagnosed at the National Veterinary Research and Quarantine Service (Kyunggi, Korea) from 1998 to 2002. Forty-one mortality events (759 birds) of 87 incidents (2,464 birds) investigated were associated with pesticide poisoning, and six organophosphates or carbamates were identified as being responsible for the poisoning. Phosphamidon was most frequently identified as the cause of poisoning, accounting for 23 mortality events. Other pesticides identified as poisons for birds were organophosphates monocrotophus, fenthion, parathion, EPN, and diazinon, and the carbamate carbofuran. Pesticide poisoning is a problem in wild birds in Korea.     

Effects of Selected Chemical Pesticides on Agamermis unka (Nematoda: Mermithidae), a Parasite of the Brown Plant Hopper,Nilaparvata lugens

Selected commercial and technical grade pesticides were tested against the egg, preparasite and adult stages of Agamermis unka , a nematode parasite of the brown planthopper, Nilaparvata lugens . The commercial insecticide, diazinon (LC = 0.37 ppm), was most toxic to the 50 preparasites, followed by phenthoate (LC = 0.43 ppm), BPMC (LC = 0.44 ppm), IBP 50 50 (LC = 0.46 ppm), cartap hydrochloride (LC = 0.82 ppm) and buprofezin + isoprocarb 50 50 (LC = 1.11 ppm). The least toxic commercial pesticide tested was the fungicide, pencycuron 50 (LC = 2.19 ppm). Out of 12 technical grade insecticides tested, phenthoate, monocrotophos, 50 diazinon and carbofuran (LC = 0.37-0.46 ppm) were highly toxic to the preparasites, followed by 50 buprofezin, BPMC and fenitrothion (LC = 0.74-0.86 ppm). Fenthion, etofenprox, chlorpyrifos, 50 imidacloprid and MIPC (LC = 1.11-2.19 ppm) were the technical grade insecticides least toxic 50 to the preparasites. Most preparasites survived for up to 24 h at the low insecticide concentrations (0.63 and 0.31 ppm). Preparasites that were exposed to BPMC for 24 h at concentrations as high as 5.0 ppm and survived the treatments infected brown planthopper nymphs. Four selected insecticides-chlorpyrifos, BPMC, imidacloprid and carbofuran-had significant adverse effects on A. unka egg hatching. Eggs that were in the insecticide solution for 168 h fared poorly with imidacloprid having the best survival ( > 2% of the eggs hatching at 0.04 ppm). No eggs hatched from the other insecticide treatments. Three selected insecticides, BPMC, imidacloprid and chlorpyrifos, tested against adult A. unka showed that most adults survived the exposure to the insecticides between 0.31 and 2.5 ppm. At 5.0 ppm of BPMC or chlorpyrifos none of the adults survived, whereas with imidacloprid 70% of the adults survived. Egg deposition by the surviving adults was greatly reduced in those treated with the insecticides compared with those in the controls. Imidacloprid had some negative impact on the preparasites' ability to infect BPH nymphs, but it had the least detrimental effect of the insecticides tested on preparasite survival and on the eggs and adults of A. unka .     

Genotoxic effects of some organophosphorous pesticides. I. Induction of micronuclei in bone marrow cells in rat

The genotoxic effects of 4 organophosphorous pesticides, i.e. ekatin, fenitrothion, methylparathion and phorate, were examined employing the micronucleus test in bone marrow cells of the rat. Methylparathion and phorate were found to be mutagenic, while ekatin was weakly mutagenic. The frequency of micronuclei induction by fenitrothion did not differ significantly from that noticed in negative control.     

韭菜上五种有机磷农药的残留监测与安全性评价

【目的】2013—2016年,在北京、天津、河北和山东采集韭菜样品,采用超高效液相色谱-三重四级杆串联质谱法检测甲胺磷、甲拌磷、甲基对硫磷、对硫磷和毒死蜱的残留量,并对其残留安全性进行评价。【方法】韭菜样品用乙腈提取,石墨碳固相萃取小柱净化,超高效反相液相色谱分离,三重四级杆质谱检测,基质匹配标准溶液的外标法定量,在添加浓度为0.01~5.0 mg/kg时,方法的准确度、灵敏度和精密度满足农药残留检测的要求。【结果】甲胺磷的最高检出浓度由70.51 mg/kg降低到0.03 mg/kg,超标率由38.10%降到2.03%;甲拌磷的最高检出浓度由6.45 mg/kg降低到0.04 mg/kg,超标率由23.81%降到1.35%;甲基对硫磷的最高检出浓度由6.62 mg/kg降低到0.13 mg/kg,超标率由25.40%降到2.70%;毒死蜱的最高检出浓度由3.95 mg/kg降低到0.47 mg/kg,超标率由15.87%降到4.73%;对硫磷的最高检出浓度由22.69mg/kg降低到0.03 mg/kg,超标率由15.08%降到1.35%。【结论】上述农药的最高残留检出浓度和超标率大幅降低,但是韭菜中仍能检出少量残留。应加强安全综合防治技术的研发,加强安全用药的宣传和指导,保障韭菜产品安全。     

A multi-analyte method for the quantification of contemporary pesticides in human serum and plasma using high-resolution mass spectrometry

We have developed a sensitive and accurate analytical method for quantifying 29 contemporary pesticides in human serum or plasma. These pesticides include organophosphates, carbamates, chloroacetanilides, and synthetic pyrethroids among others and include pesticides used in agricultural and residential settings. Our method employs a simple solid-phase extraction followed by a highly selective analysis using isotope dilution gas chromatography-high-resolution mass spectrometry. Our method is very accurate, has limits of detection in the low pg/g range and coefficients of variation of typically less than 20% at the low pg/g end of the method linear range. We have used this method to measure plasma pesticide concentrations in females living in an urban area. We found detectable concentrations of carbaryl/naphthalene, propoxur, bendiocarb, chlorpyrifos, diazinon, dicloran, captan and folpet or their metabolites in more than 20% of the plasma samples tested.     

Evaluating membrane technology for clarification of sugarcane juice

The sugar industry needs to find efficient methods in clarifying the raw sugarcane juice in order to improve the quality of the clarified juice and to reduce or eliminate the usage of chemicals (lime). Conventional clarifiers use heavy equipment which lead to high operating costs and associated environmental problems. In sugar mills, ensuring the production of juice of consistently high clarity and low colour through the clarification process is a challenging task. The variations in the incoming juice characteristics due to differences in cane variety, soil and growing conditions, weather patterns and season make this task even more challenging. Membrane filtration promises superior quality juice with better clarity, much lower viscosity and noticeable colour removal. Ultrafiltration of clarified sugarcane juice can be done through spiral wound or flat sheet filtration systems using polymeric membranes or tubular filtration systems using ceramic membranes. This review evaluates the applications of membrane technology in sugar industry all over the world and the need for it in the Australian sugar industry. This is an important first step to identify the appropriate types and applications of membranes.     

固定化果胶酶澄清果汁的条件及效果

利用固定化果胶酶对四种不同果汁澄清条件及效果进行研究,结果表明,固定化果胶酶澄清四种不同果汁的效果明显,其中澄清桔汁的果胶酶重复使用20次以上,酶活力及透光率仍可维持在80%以上,其最适反应条件是:果汁浓度50%;pH 3.0~3.5;温度45~50℃;反应时间2小时;酶量每毫升果汁0.05 g固定化果胶酶;澄清时间20小时。     

Phytoremediation of ethion by water hyacinth (Eichhornia crassipes) from water

The potential of water hyacinth (Eichhornia crassipes) to remove a phosphorus pesticide ethion were investigated. The disappearance rate constants of ethion in culture solutions were 0.01059, 0.00930, 0.00294, and 0.00201 h-1 for the non-sterile planted, sterile planted, non-sterile unplanted, and sterile unplanted treatment, respectively, which were significantly different and implied that plant uptake and phytodegradation contributed 69% and that of microbial degradation took up 12% to the removal of the applied ethion. The accumulated ethion in live water hyacinth plant decreased by 55-91% in shoots and 74-81% in roots after the plant growing 1 week in ethion free culture solutions, suggesting that plant uptake and phytodegradation might be the dominant process for ethion removal by the plant. This plant might be utilized as an efficient, economical and ecological alternative to accelerate the removal and degradation of agro-industrial wastewater polluted with ethion.     

Cloning of mpd gene from a chlorpyrifos-degrading bacterium and use of this strain in bioremediation of contaminated soil

An effective chlorpyrifos-degrading bacterium (named strain YC-1) was isolated from the sludge of the wastewater treating system of an organophosphorus pesticides manufacturer. Based on the results of phenotypic features, phylogenetic similarity of 16S rRNA gene sequences and BIOLOG test, strain YC-1 was identified as the genus Stenotrophomonas. The isolate utilized chlorpyrifos as the sole source of carbon and phosphorus for its growth and hydrolyzed chlorpyrifos to 3,5,6-trichloro-2-pyridinol. Parathion, methyl parathion, and fenitrothion also could be degraded by strain YC-1 when provided as the sole source of carbon and phosphorus. The gene encoding the organophosphorus hydrolase was cloned using a PCR cloning strategy based on the known methyl parathion degrading (mpd) gene of Plesiomonas sp. M6. Sequence blast result indicated this gene has 99% similar to mpd. The inoculation of strain YC-1 (10(6) cells g(-1)) to soil treated with 100 mg kg(-1) chlorpyrifos resulted in a higher degradation rate than in noninoculated soils. Theses results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.     

Removal of pesticides from white wine by the use of fining agents and filtration

The effects of four clarification agents (bentonite, charcoal, PVPP and potassium caseinate) on the removal of residues of three fungicides (famoxadone, fluquinconazole and trifloxystrobin) applied directly to a racked white wine, elaborated from Airen variety grapes from the D.O. Region of Jumilla (Murcia, Spain) are studied. The clarified wines were filtered with 0.45 microm nylon filters to determine the influence of this winemaking process in the disappearance of fungicide residues. Hydro-alcoholic solutions with the three fungicides at concentrations of 1 and 2 ppm were then added through intense stirring to each of the containers. Two hours later, the corresponding clarifying agent was added with intense stirring for some minutes. The containers were then sealed and left to settle for five days. Once the clean wines had been racked, they were filtered through nylon 0.45 microm pore filters. All assays were performed three times. Analytical determination of fluquinconazole and trifloxystrobin was performed by gas chromatography with an electron captor detector (ECD), while that of famoxadone was made using an HPLC-DAD. For the three fungicides, the highest elimination is produced with the clarification by charcoal, reaching Levels of removal of 100% in all cases. For the four clarifying agents, the highest elimination is produced for the fluquinconazole residues. The fungicide which is retained most in the lees is famoxadone, since it has the lowest solubility of the three pesticides studied. The highest percentage of residues in the lees is obtained for the assay with charcoal. The filtration process of the clarified wines using the four agents studied is not effective, since the elimination percentage is generally lower than 10% of the initial residues in the non-clarified wines.     

Effects of long-term exposure to low levels of organophosphorous pesticides and their mixture on altered antioxidative defense mechanisms and lipid peroxidation in rat liver

Organophosphorous pesticides, commonly used in agriculture for achieving better quality products, are toxic substances that have harmful effects on human health. Recent research on pesticides, especially pesticide mixtures, has shown that they are one of the key environmental health issues. The aim of the present study was to investigate whether dichlorvos, acephate, dimethoate and phorate, either used separately or in combination, can induce oxidative damage in rat livers. The levels of superoxide dismutase, glutathione peroxidase, catalase and lipid peroxidation products (malondialdehyde) were used as criteria. Low, middle and high doses of pesticides in drinking water were continuously administered orally to rats ad libitum for 24 weeks. Results show that the antioxidative defense mechanisms and lipid peroxidation in the rat livers display different responses, depending on the pesticide treatments and doses. The parameters for acephate, dichlorvos, phorate and dimethoate in the low-dose group, and the corresponding low-dose co-treated group were not altered. The oxidative damage in rat livers showed different responses with increasing pesticide dose according to the different pesticide treatments. The combination group of dichlorvos, acephate, dimethoate and phorate displayed different responses compared with the single pesticide-treated group. However, these responses did not constitute the sum of the response produced by each pesticide in the liver.     

Effects of co-existed proteins on measurement of pesticide residues in blood by gas chromatography-mass spectrometry

Accurate measurement of pesticides in biological fluids such as blood is important for quantifying environmental exposures. Beyond sample enrichment and separation, the method presented here is focused on studies of interactions between pesticides and co-existed proteins. It was experimentally demonstrated that entrapped or adsorbed pesticide residues within the folded native structures of proteins were poorly recovered using direct solvent extraction solely. We described here an effective approach termed Enzymatic Digestion-Organic Solvent Extraction (eDOSE) that utilizes the enzymatic approach to disrupt the folded structures of proteins and release entrapped or adsorbed pesticide residues. In this approach, samples were first reduced, alkylated, tryptically digested and then diluted 10 times before the subsequent extraction using an n-hexane solution. Resultant pesticide residues were determined by capillary gas chromatography coupled with a mass spectrometer. Mean recoveries of the 5 organophosphorus pesticides pre-spiked in fish blood including diazinon, parathion-methyl, malathion, parathion-ethyl and ethion were 85%, 95%, 84%, 103%, and 43% respectively using eDOSE strategy but only 24%, 45%, 40%, 27%, and 29% respectively using direct solvent extraction approach. The eDOSE approach was effective for demonstrating the critical role of folded native structure of serum albumin in adsorption of exogenous chemicals. It provides an alterative means for denaturation of proteins when the target analytes are not stable in acidic solution or entrapped within the protein aggregates caused by organic solvents such as acetone that have been applied for protein denaturation. The eDOSE approach should be able to combine with other advanced techniques of enrichment and separation for more efficient and accurate measurement of target compounds present in the context of complex biological systems. This approach can provide wide applications to the analysis of a variety of small molecules including environmental pesticide residues and metabolites as well as other toxins present in cells, tissues and biofluids.     

Simultaneous removal of chlorpyrifos and dissolved organic carbon using horizontal sub-surface flow pilot wetlands

Rural areas of developing countries require low-cost treatment systems to purify wastewater which is contaminated with pesticides and organic matter. This work evaluated for six months the simultaneous removal of chlorpyrifos and dissolved organic matter in water using four horizontal sub-surface flow constructed wetlands (SSFCW) at a pilot scale, that were planted with Phragmites australis at 20 ± 2 °C water temperature. In each wetland, three concentrations of chlorpyrifos and three of dissolved organic carbon (DOC) were tested by liquid chromatography and an organic carbon analyzer respectively. The pesticide and DOC were added to the wetlands in synthetic wastewater. For the experiments, four wetlands of equal dimensions were used, with granular material of igneous rocks, 3.9–6.4 mm in diameter and at a depth of 0.3 m with a layer of water 0.2 m deep. For each treatment, regular sampling was carried out for the influent and effluents. As a supporting feature NH₄⁺, NO₃^? and PO₄^3? were quantified and in situ measurements of dissolved oxygen (DO), pH, electrical conductivity, water temperature and redox potential were taken. The overall removal of the chlorpyrifos (92.6%) and DOC (93.2%) was high, as was DOC removal as a function of pesticide concentration in the influent. The minimum magnitude (92.0%) was reached with 425.6 μg L^?1 of chlorpyrifos and, with the highest pesticide removal (96.8%). At lower concentrations of the agrochemical, DOC removal increased. The removals were possibly due to mineralization processes, biological decomposition and sorption in plants. These findings demonstrate that SSFCW are capable of simultaneously removing dissolved organic matter and organophosphate pesticides such as chlorpyrifos, which indicate that chlorpyrifos did not interfere with the removal of organic material.