Pesticide volatilization from plants: improvement of the PEC model PELMO based on a boundary-layer concept

Calculation of pesticide volatilization from plants as an integral component of pesticide fate models is of utmost importance, especially as part of PEC (predicted environmental concentrations) models used in the registration procedures for pesticides. A mechanistic approach using a laminar air-boundary layer concept to predict volatilization from plant surfaces was compared to data obtained in a wind-tunnel study after simultaneous application of parathion-methyl, fenpropimorph, and quinoxyfen to winter wheat. Parathion-methyl was shown to have the highest volatilization during the wind-tunnel study of 10 days (29.2%). Volatilization of quinoxyfen was about 15.0%, revealing a higher volatilization tendency than fenpropimorph (6.0%), which is attributed to enhanced penetration of fenpropimorph counteracting volatilization. Predictions of the boundary-layer approach were markedly influenced by the selected values for the equivalent thickness of the boundary layer and rate coefficients, thus indicating that future improvements of the approach will require a deeper understanding of the kinetics of the underlying processes, e.g. phototransformation and penetration. The boundary-layer volatilization module was included in the European registration model PELMO, enabling simultaneous calculation of volatilization from plants and soil. Application of PELMO to experimental findings were the first comprehensive PEC model calculations to imply the relevant processes affecting the postapplication fate of pesticides.     

Measuring and predicting environmental concentrations of pesticides in air after application to paddy water systems

In this study, the volatilization of five pesticides applied to an artificial flooded paddy field was assessed using the theoretical profile shape (TPS) and the integrate horizontal flux (IHF) techniques. The dataset derived was utilized to improve the volatilization routine of the rice water quality (RICEWQ) model. The masses of pesticides ethoprophos, procymidone, metalaxyl, chlorpyrifos, and chlorpyrifos methyl volatilized from paddy water and their concentrations in paddy water were determined for a period of 6 d after application. The highest and lowest volatilization losses were observed for chlorpyrifos and metalaxyl, respectively, accounting for 3.3% and 0.03% of their initially applied amount. A rapid pesticide dissipation was evident in paddy water during the study period. The RICEWQ model was used to simulate the fate of pesticides in the artificial paddy system. The Kvolat, an empiric coefficient used by the model as an input parameter, was calculated for all pesticides through model calibration. RICEWQ simulated well the fate of pesticides in paddy water. A significant regression correlation between Henry's law constant (Hk) and Kvolat of the studied compounds was established which could facilitate the parametrization of the model for describing pesticide volatilization.     

Volatilization of parathion and chlorothalonil from a potato crop simulated by the PEARL model

The volatilization of pesticides from crop canopies in the field should be modeled within the context of evaluating environmental exposure. A model concept based on diffusion through a laminar air-boundary layer was incorporated into the PEARL model (pesticide emission assessment at regional and local scales) and used to simulate volatilization of the pesticides parathion and chlorothalonil from a potato crop in a field experiment. Rate coefficients for the competing processes of plant penetration, wash off, and phototransformation in the canopy had to be derived from a diversity of literature data. Cumulative volatilization of the moderately volatile parathion (31% of the dosage in 7.6 days) could be simulated after calibrating two input data derived for the related compound parathion-methyl. The less volatile and more slowly transformed chlorothalonil showed 5% volatilization in 7.6 days, which could be explained by the simulation. Simulated behavior of the pesticides in the crop canopy roughly corresponded to published data.     

基质固相分散-气相色谱检测菊花中有机磷农药残留

建立菊花中14种有机磷农药残留量的气相色谱分析方法。样品用乙腈-丙酮(4:1,V/V)提取,经基质固相分散技术净化,以乙腈-甲苯(3:1,V/V)洗脱,气相色谱-火焰光度检测,外标法定量。在0.05～1.0mg/kg的添加水平,14种有机磷的平均回收率在84.54%～108.54%之间,相对标准偏差在0.66%～6.31%,该方法的检出限为0.01～0.04mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。采用所建立方法测定了黄山贡菊、杭白菊和胎菊3种代表性菊花中14种有机磷农药残留量,结果表明,黄山贡菊检出乐果1.68mg/kg、毒死蜱0.17mg/kg、硫环磷0.28mg/kg,杭白菊检出毒死蜱0.09mg/kg,胎菊检出乐果0.25mg/kg、毒死蜱0.14mg/kg、伏杀磷0.08mg/kg。     

四种农药耐受真菌的鉴定及降解效果

目的分析4种农药耐受真菌的农药残留的降解效果。方法分别添加浓度为1.0 mg/kg的4种常见农药甲拌磷、毒死蜱、三唑酮、腐霉利,通过不同时间的培养,对其农药残留的降解水平进行分析,采用18S rDNA/ITS对该菌株进行DNA提取,将提取后的DNA进行ITS扩增测序,并运用BLAST进行序列比对。结果通过分子鉴定,该菌株为真菌中根霉属(Rhizopus),对以上4种农药均具有降解作用,降解能力依次为甲拌磷腐霉利三唑酮毒死蜱。该菌株对甲拌磷降解效果最好,在培养时间达到72 h时,降解率为100%,其余降解率分别为腐霉利88%、三唑酮85%、毒死蜱50%。结论该菌株在培养时间为48 h时,对4种农药残留的降解水平最佳,对甲拌磷降解水平最好;培养时间到达72 h时,对甲拌磷降解率达到100%。     

Pesticide residue monitoring in Korean agricultural products, 2003–05

Between 2003 and 2005, a total of 11,716 samples were collected and analysed to determine the level of pesticides residues. Multi-residue methods (MRMs) capable of simultaneously determining 250 pesticides were used. Of the 11,716 samples, 89.1% had no detectable residues and 1.7% had violative residues. The detection rates by commodity group were 11.4, 8.6, 0.3, and 0.02% for vegetables, fruit, grain, mushrooms, and the others, respectively. Agricultural products with pesticide residues were pepper, Perilla frutescens, leafy lettuce and spinach in decreasing order. Of the 250 pesticides that were monitored, 70 pesticides were actually found. Procymidone, endosulfan, chlorfenapyr, metalaxyl, and diethofencarb were frequently detected. Of the samples, parsley, Petasites hybridus, Aster scaber and leek had high violative rates of 23.1, 12.6, 8.2, and 7.9%, respectively. From violative samples, procymidone, endosulfan, metalaxyl, diazinon and chlorpyrifos were frequently detected. The violation rates were 1.71, 1.68, and 1.76% in 2003, 2004 and 2005, respectively, and the detection rates were 8.5, 12.0, and 13.3% in 2003, 2004, and 2005, respectively.     

Application of Solid‐Phase Micro‐Extraction (SPME) for Determining Residues of Chlorpyrifos and Chlorpyrifos‐Methyl in Wine with Gas Chromatography (GC)

The incorrect use of insecticides in many countries' vineyards may result in some toxicological risks for the consumers by their presence on the grapes. In this research, a rapid gas chromatographic method was used for the determination of the residue levels of two organophosphorus pesticides (chlorpyrifos and chlorpyrifos‐methyl) in wine. Pesticides are described and compared with each other. Ten red wines from two different regions of Turkey were analyzed for their chlorpyrifos and chlorpyrifos‐methyl content. The samples were diluted with water and extracted by solid‐phase micro extraction. Nitrogen‐Phosphorus Detection (NDP) and Electron‐Capture Detection (ECD) were used to identify and quantify the pesticides, the findings being confirmed using Mass Spectrometric Detection. Individual detection limits were in the range of (chlorpyrifos) 0.02‐(chlor‐pyrifos‐methyl) 0.1 ng. Limits of quantification varied from (chlorpyrifos) 0.01‐(chlorpyrifos‐methyl) 0.05 mg kg^?1. The maximum residues limits of the two pesticides in the Turkish wines examined were much lower than the Turkish and European Union limits.     

QuEChERS-GC/MS法解析枯草芽胞杆菌降解白菜叶际毒死蜱残留特性

在中国,毒死蜱作为替代高毒有机磷农药的最佳选择之一,已被广泛用于控制蔬菜生产过程中病虫害,然其带来的食品安全问题引起了人们越来越多的关注,因此建立快速检测毒死蜱残留的新方法显得尤为重要。本研究构建了一种改进的QuEChERS样品预处理和气相色谱-质谱(GC-MS)联用法,以快速测定白菜叶际毒死蜱的残留量。样品用含1%乙酸的乙腈提取,用适量N-丙基乙二胺(PSA)、无水MgSO_4、石墨化炭黑(GCB)和C18填料净化,GC-MS检测,外标法定量。结果表明:毒死蜱在质量浓度为0.20～1.00mg/L时,线性关系良好,R大于0.999;添加水平为0.10～0.50 mg/kg时,平均回收率为72.00%～111.00%,相对标准偏差为1.30%～1.60%,检出限(LOD)为0.005 mg/kg,定量限(LOQ)为0.01 mg/kg。该方法简便、快速、准确、灵敏,能够满足白菜叶际毒死蜱残留的定性和定量分析检测。枯草芽胞杆菌3374对白菜叶际毒死蜱残留具备有效降解能力。     

河北产区桃农药残留风险评估

目的 明确河北产区桃中农药残留水平和风险状况。方法 在河北省采集70份桃样品进行农药残留检测与分析,对检出农药残留行急性和慢性膳食摄入风险评估,并利用风险排序矩阵对农药残留风险大小进行排序。结果 70批次桃样品共检出农药残留33种,农药残留检出率为100%,个别样品存在农药残留超标现象,超标农药为多菌灵和甲氨基阿维菌素苯甲酸盐。桃中检出农药的慢性膳食摄入风险(%ADI)在0.00%～1.06%之间,急性膳食摄入风险(%ARfD )在0.00%～11.34%之间。根据农药残留风险排序结果,高风险农药共有5种,其中毒死蜱和甲氨基阿维菌素苯甲酸盐检出率较高,分别为45.7%和18.6%。结论 河北地区桃样品中农药残留检出率较高,但94.3%的样品中农药残留量符合国家限量标准,桃中农药残留急性和慢性膳食摄入风险均处于较低水平,其中,多菌灵、毒死蜱和甲氨基阿维菌素苯甲酸盐是桃中应重点关注的风险因子。     

Exposure to pesticides residues from consumption of Italian blood oranges

This paper reports the results of a 5-year study to evaluate pesticide levels, derived from orchard activities, on Italy's most common orange cultivar (Citrus sinensis, L. Osbeck, cv. Tarocco). Using a Bayesian approach, the study allowed both the qualitative (number) and quantitative distributions (amount) of pesticides to be determined with its own probability value. Multi-residue analyses of 460 samples highlighted the presence of ethyl and methyl chlorpyrifos, dicofol, etofenprox, fenazaquin, fenitrothion, imazalil, malathion and metalaxil-m. A total of 30.5% of samples contained just one pesticide, 2.16% two pesticides and 0.65% of samples had three pesticides present simultaneously. The most common residue was ethyl chlorpyrifos followed by methyl chlorpyrifos. Estimated daily intake (EDI) values for ethyl and methyl chlorpyrifos, as well as the distance from the safety level (non-observed adverse effect level, NOAEL), were calculated. The risk was differentiated (1) to take account of the period of actual citrus consumption (180 days) and (2) to discriminate the risk derived from eating oranges containing a certain level of chlorpyrifos from unspecified pesticides. The most likely EDI values for ethyl chlorpyrifos derived from Italian blood orange consumption are 0.01 and 0.006 mg/day calculated for 180 and 365 days, respectively. Considering the probability of the occurrence of ethyl chlorpyrifos, these EDI values are reduced to 2.6 × 10^?3 and 1.3 × 10^?3 mg/day, respectively. For methyl chlorpyrifos, the most likely EDI values are 0.09 and 0.04 mg/day, respectively; considering the probability of its occurrence, the EDI values decrease to 6.7 × 10^?3 and 3.4 × 10^?3 mg/day, respectively. The results confirmed that levels of pesticides in Italian Tarocco oranges derived from a known controlled chain of production are safe.     

2010—2011年青岛市市售蔬菜农药残留状况分析

了解青岛市市售蔬菜农药残留状况,发现食品安全隐患,为进一步制定和采取有效预防控制措施提供理论依据。 方法 于2010—2011年间,在青岛市调查网点抽取蔬菜样品5 228份,依据NY/T 761—2008《蔬菜和水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯类农药多残留的测定》对样品进行检测,依据GB 2763—2014《食品中农药最大残留限量》对38种农药进行判定。 结果 农药残留检出率为24.77%,总不合格率为15.57%;各类蔬菜中以葱蒜类蔬菜农药检出率和不合格率最高,其次为绿菜类蔬菜,各类农药不合格率排序为:拟除虫菊酯类农药>有机磷农药>有机氯农药>氨基甲酸酯类农药,其中主要的不合格农药为氯氰菊酯(3.18%)、百菌清(2.54%)、毒死蜱(2.16%)和克百威(1.80%);混合农药检出率为5.87%,占检出样品的23.71%,不合格率高达4.65%。第四季度蔬菜农药残留检出率和不合格率最高,分别为42.05%和20.62%。 结论 青岛市市售蔬菜农药残留状况整体良好,但仍存在一些问题,应采取有效措施加强蔬菜的监督管理,确保市民使用蔬菜的安全。     

Ultrasound-Assisted Emulsification-Microextraction/Ion Mobility Spectrometry Combination: Application for Analysis of Organophosphorus Pesticide Residues in Rice Samples

The present paper describes the validation of ultrasound-assisted emulsification-microextraction method followed by ion mobility spectrometry (IMS) detection for simultaneous determination of two organophosphorus pesticides, diazinon and chlorpyrifos. Ultrasound radiation was applied for accelerating the emulsification of microliter organic solvent in aqueous solutions and enhancing the microextraction efficiency. This preconcentration step combined with IMS detection provided a precise and accurate method for determination of trace amounts of diazinon and chlorpyrifos pesticides. The effect of parameters influencing the extraction efficiency such as sonication time, type of extraction solvent, extraction solvent volume, and salt concentration were investigated and discussed. The enrichment factors found, under optimum conditions, were 230 and 300 for diazinon and chlorpyrifos, respectively, with corresponding LOD of 2.1 and 3.2 μg L^?1. The presented method can be applied for the determination of diazinon and chlorpyrifos in the range 6.0–700 and 8.9–750 μg L^?1, respectively, with correlation coefficients (R ²)?>?0.99. The applicability of the proposed method was evaluated by determination of the residues of the investigated pesticides in rice paddy water gathered from four stations during 60 days after spraying (June 2014), and in storage rice samples in Mazandaran province, Iran.     

Evaluation of pesticide residues in fruits and vegetables from Algeria

ABSTRACT

A total of 160 samples of 13 types of fresh fruits and vegetables from domestic production and import were analysed to detect the presence of pesticide residues. Analysis was performed by multi-residual extraction followed by gas chromatography–mass spectrometry. In 42.5% of the tested samples, no residues were found and 12.5% of samples contained pesticide residues above maximum residue limits. Risk assessment for long-term exposure was done for all pesticides detected in this study. Except chlorpyrifos and lambda-cyhalothrin, exposure to pesticides from vegetables and fruits was below 1% of the acceptable daily intake. Short-term exposure assessment revealed that in seven pesticide/commodity combinations, including three pesticides (chlorpyrifos, deltamethrin and lambda-cyhalothrin), the acute reference dose had been exceeded.     

不同干燥方法对苹果中毒死蜱残留的影响

目的 了解苹果干燥加工过程中毒死蜱残留的降解规律,为苹果干燥产品中农药残留风险的评估提供科学的依据。方法 以红富士苹果为研究对象,采用热风干燥、微波干燥、阳光干燥对苹果片进行了处理,毒死蜱的残留量使用高效液相质谱检测。同时,利用加工因子(PF)建立了毒死蜱的变化模型,分析了干燥过程中水分的扩散系数和苹果片的复水率。结果 毒死蜱在苹果干燥过程中的变化是动态的,它的变化复合动力学模型,微波干燥和阳光干燥对毒死蜱的去除率高于热风干燥。毒死蜱的残留量与干燥条件以及农药的理化性质相关。结论 在苹果的工业生产中,推荐采用微波和阳光干燥来处理苹果,以降低毒死蜱残留带来的食品安全风险。     

Degradation of pyrazophos and methidathion in fortified red and white wine under conditions of light and darkness

The decomposition of the pesticides methidathion and pyrazophos in red and white wine stored under different conditions was studied. Samples of red and white wine were fortified with 3.25 mg/kg of each of the pesticides. One lot was stored under diffuse daylight and the other in a dark closet. Both lots were stored at the same temperature. Their degradation was followed for 80 days. Half-lives of the pesticide methidathion in white and red wine stored in diffuse daylight were 20.1 and 20.0 days, respectively, and 21.1 and 24.2 days for those stored in conditions of darkness. Corresponding half-lives for pyrazophos were 29.7 and 29.1 days for storage in daylight conditions and 31.1 and 34.5 days in darkness conditions. Photodegradation was not found to play any important role in the decomposition of these pesticides under the conditions used.     

Pesticides in the atmosphere across Canadian agricultural regions

The Canadian Atmospheric Network for Currently Used Pesticides (CANCUP) was the first comprehensive, nationwide air surveillance study of pesticides in Canada. This paper presentsthe atmospheric occurrence and distribution of pesticides including organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), acid herbicides (AHs), and neutral herbicides (NHs) during the spring to summer of 2004 and 2005 across agricultural regions in Canada. Atmospheric concentrations of pesticides varied within years and time periods, and regional characteristics were observed including the following: (i) highest air concentrations of several herbicides (e.g., mecoprop, triallate, and ethalfluralin) were found at Bratt's Lake, SK, a site in the Canadian Prairies; (ii) the west-coast site at Abbotsford, BC, had the maximum concentrations of diazinon; (iii) the fruit and vegetable growing region in Vineland, ON, showed highest levels for several insecticides including chlorpyrifos, endosulfan, and azinphos-methyl; (iv) high concentrations of atrazine and metolachlor were measured at St. Anicet, QC, a corn-growing region; (v) the Kensington site in PEI, Canada's largest potato-producing province, exhibited highest level of dimethoate. Analysis of particle- and gas-phase fractions of air samples revealed that most pesticides including OCPs, OPPs, and NHs exist mainly in the gas phase, while AHs exhibit more diversity in particle-gas partitioning behavior. This study also demonstrated that stirred up soil dust does not account for pesticides that are detected in the particle phase. The estimated dry and wet deposition fluxes indicate considerable atmospheric inputs for some current-use pesticides (CUPs). This data set represents the first measurements for many pesticides in the atmosphere, precipitation, and soil for given agricultural regions across Canada.     

茶基质对气相色谱法定量分析有机磷农药的影响

选用茶叶、茶汤为基质,气相色谱法分析茶叶、茶汤对毒死蜱、甲基对硫磷、敌敌畏的基质效应。结果表明:优化色谱条件下,3种农药有较好分离效果和重现性。以不添加基质标准曲线与分别添加2种基质标准曲线的R2值均大于0.99;同一种农药基质标准曲线斜率与纯溶剂标准曲线斜率之比得出,基质增强效应明显,茶叶茶汤对3种农药的基质效应为敌敌畏 > 甲基对硫磷 > 毒死蜱。基质对回收率有较大影响,以添加基质的标准曲线定量,3种农药3个加标水平的回收率为74.75%~113.20%;以不添加基质的标准曲线定量,3种农药3个加标水平的回收率为80.40%~133.80%,其中茶叶3种农药加标量为0.4 mg/kg时,3种农药的回收率均超过120%。RSD(相对标准偏差)在0.79%~6.57%之间,基质对RSD影响不明显。说明茶基质对低浓度3种农药具有明显基质增强效应,采用基质标准溶液的定量方式对低浓度水平有机磷农药的检测有较好准确度。     

Degradation behaviour of methamidophos and chlorpyrifos in apple juice treated with pulsed electric fields

Apple juice (13 °Brix) spiked with methamidophos and chlorpyrifos (2–3 mg/l of each compound) was treated by pulsed electric fields (PEF), and pesticide residues were quantified by gas chromatography with flame photometric detection (GC-FPD). Results showed that electric field strength (8–20 kV/cm) and pulse number (6–26 pulses) have significant effects on the degradation of methamidophos and chlorpyrifos. PEF treatment is effective for the degradation of methamidophos and chlorpyrifos residues in apple juice, and chlorpyrifos is much more labile to PEF than methamidophos. An increase in either pulse number or electric field strength could speed the degradation of methamidophos and chlorpyrifos, and the kinetics equations and related parameters quantitatively characterized the degradation behavior of the pesticides. The exponential model better fits the experimental data for all treatments than the linear model.     

新疆红枣农药残留风险评估与排序

为明确残留农药对新疆红枣质量安全的危害水平及其排序,本文以新疆10县市产出的124份红枣样品为研究对象,并对37种农药残留进行了测定,在此基础上,通过急性、慢性膳食摄入风险分析,探讨了残留农药对红枣质量安全的危害水平;并采用风险矩阵,对残留农药进行了风险排序。结果显示,样品中残留11种农药;残留农药的% ADI(慢性膳食摄入风险)值远小于100%;10种农药的% ARfD值(急性膳食摄入风险)也远低于100%;较其他残留农药,哒螨灵、毒死蜱、苯醚甲环唑、氯氟氰菊酯、氯氰菊酯、甲氰菊酯6种残留农药风险值相对较高,均大于12.05。结论:新疆红枣残留农药的膳食风险较低,哒螨灵、毒死蜱、苯醚甲环唑、氯氟氰菊酯、氯氰菊酯、甲氰菊酯为需重点关注的农药。     

Reduction in pesticide residue levels in olives by ozonated and tap water treatments and their transfer into olive oil

The effects of different wash times (2 and 5 min) with tap and ozonated water on the removal of nine pesticides from olives and the transfer ratios of these pesticides during olive oil production were determined. The reliability of the analytical methods was also tested. The applied methods of analysis were found to be suitable based on linearity, trueness, repeatability, selectivity and limit of quantification all the pesticides tested. All tap and ozonated water wash cycles removed a significant quantity of the pesticides from the olives, with a few exceptions. Generally, extending the wash time increased the pesticide reduction with ozonated water, but did not make significant differences with tap water. During olive oil processing, depending on the processing technique and physicochemical properties of the pesticides, eight of nine pesticides were concentrated into olive oil (processing factor > 1) with almost no significant difference between treatments. Imidacloprid did not pass into olive oil. Ozonated water wash for 5 min reduced chlorpyrifos, β-cyfluthrin, α-cypermethrin and imidacloprid contents by 38%, 50%, 55% and 61% respectively in olives.