Determination of azoxystrobin, topramezone, acetamiprid, fluometuron and folpet in their commercially available pesticide formulations by liquid chromatography.

A rapid, simple, precise and accurate high performance liquid chromatographic (HPLC) analytical method was developed and validated for the determination of the active substances (a.s.) azoxystrobin, topramezone, acetamiprid, fluometuron and folpet in their respective commercially available formulations. The method was used for the analysis of samples under the frame of the national quality control program of plant protection products in the Greek market. Chromatographic separation of the active substances from additives and co-formulants is achieved using isocratic elution with acetonitrile and 0.1% phosphoric acid solution (60:40 v/v) at a flow rate of 0.4 mL min-1 on a C18 monolithic column (Chromolith Performance-RP18e 100 × 4.6 mm) and UV detection at 230 nm. Validation parameters of the method fulfilled acceptability criteria. Recovery of all individual compounds was in the range 97.8-100.9%. Precision expressed as relative standard deviation was lower than the theoretical values of the modified Horwitz equation. Correlation coefficients of linearity of response were better than 0.999. The benefits of the proposed method are significant reduction in analysis time and total cost since all analytes were determined with the same extraction procedures and chromatographic system. Analysis of real samples for all active ingredients confirmed fitness for purpose of the suggested method.

Ecologically controlling insect and mite pests of tea plants with microbial pesticides: a review.

Insect and mite pests are damaging stressors that are threatening the cultivation of tea plants, which result in enormous crop loss. Over the years, the effectiveness of synthetic pesticides has allowed for its prominent application as a control strategy. However, the adverse effects of synthetic pesticides in terms of pesticide residue, environmental contamination and insect pest resistance have necessitated the need for alternative strategies. Meanwhile, microbial pesticides have been applied to tackle the damaging activities of the insect and mite pests of tea plants, and their performances were scientifically adjudged appreciable and environmental friendly. Herein, entomopathogenic microbes that were effective against tea geometrid (Ectropis obliqua Prout), tea green leafhopper (Empoasca onukii Matsuda), paraguay tea ampul (Gyropsylla spegazziniana), tea mosquito bug (Helopeltis theivora Waterhouse) and red spider mite (Oligonychus coffea Nietner) have been reviewed. The current findings revealed that microbial pesticides were effective and showed promising performances against these pests. Overall, this review has provided the basic and integrative information on the integrated pest management (IPM) tool(s) that can be utilized towards successful control of the aforementioned insect and mite pests.

An analysis of the setting of the acute reference dose (ARfD) for pesticides in Europe.

To protect human health, acute reference values have been established for pesticides which have the potential to cause a toxic effect after acute human exposure. These values are used to identify exposure levels below which there is no appreciable risk. Comprehensive reference documents, including OECD criteria, are available to aid identification of relevant toxicological endpoints. Within Europe, there is a concern that the identification process is inconsistent and unnecessarily conservative such that safe products with no established human health risk are being restricted. For this reason, the basis for the setting of an acute reference dose (ARfD) has been investigated for 130 pesticides to better understand how the toxicological endpoints are selected. The investigation has shown that most ARfDs are derived from repeat dose studies and that there is an over-representation of prenatal developmental toxicity studies. There is clear evidence that ARfDs derived from rabbit developmental toxicity studies are set over conservatively with regard to acute maternal effects and often inappropriately. To facilitate an improved system, refinements to the existing process are recommended, the use of maternal data in the rabbit as the basis for deriving an ARfD is critically evaluated and a new, more pragmatic approach to ARfD derivation is proposed.

Analysis of organophosphorus and pyrethroid pesticides in organic and conventional vegetables using QuEChERS combined with dispersive liquid-liquid microextraction based on the solidification of floating organic droplet.

A simple, sensitive and environmentally-friendly method for determining organophosphorus and pyrethroid pesticides in vegetables was developed to better evaluate the risk of consuming them. The pesticides in vegetables were extracted, purified and concentrated by using the QuEChERS (quick, easy, cheap, effective, rugged and safe method) combined DLLME-SFO (dispersive liquid-liquid microextraction based on solidification of floating organic droplet) techniques. The key parameters were optimized through orthogonal array experimental design and statistical analysis. The linearity of the calibration curves was satisfied in matrix-matched standard solution with R2 ≥ 0.99. The limits of detection and limits of quantification were 0.3-1.5 and 0.9-4.7 µg/kg, respectively. The average recoveries of pesticides were 61.6-119.4% with relative standard deviations <16.1%. Furthermore, the method was applied successfully to analyse the pesticides in 15 pairs of organic and conventional vegetables. These results reflect the efficiency, reliability and robustness of the developed method.

Deriving safe short-term chemical exposure values (STEV) for drinking water.

Small and brief exceedances of chemicals above their guideline values in drinking water are unlikely to cause an appreciable increased risk to human health. As a result, short-term exposure values (STEV) can be derived to help decide whether drinking water can still be supplied to consumers without adverse health risks. In this study, three approaches were applied to calculate and compare STEV for pesticides. The three approaches included basing a STEV on the acute reference dose (ARfD) (Approach 1), removing conventional attribution rates and uncertainty factors from current guideline values (Approach 2) and extrapolating 1 d and 7 d no observed adverse effect levels (NOAEL) from existing toxicity data using a log-linear regression (Approach 3). Despite being very different methods, the three approaches produced comparable STEV generally within an order of magnitude, which often overlapped with other existing short-term exposure values such as short-term no adverse response levels (SNARL) and health advisories (HA). The results show that adjusting the current guideline value using standard extrapolation factors (Approach 2) often produced the most conservative values. Approach 2 was then applied to two other chemical classes, disinfection by-products (DBPs) and cyanotoxins, demonstrating the wider applicability of the approach.

Cohort-friendly protocol for the determination of two urinary biomarkers of exposure to pyrethroids and neonicotinoids using gas chromatography-triple quadrupole mass spectrometry.

Neonicotinoids (NEOs) and synthetic pyrethroids (PYRs) are active ingredients of commercial pesticides and/or insecticides with extensive indoor and outdoor applications, worldwide. Improved exposure metrics are warranted for NEOs and PYRs, if we are to better understand their human health effects. A cohort-friendly protocol for determining non-specific biomarkers of exposure to NEOs and PYRs, e.g. 6-chloronicotinic acid (6-CN) and 3-phenoxybenzoic acid (3-PBA), respectively, in human urine voids was proposed. A series of optimization experiments were conducted to validate the bioanalytical protocol using gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS/MS) in MRM mode. The method reached low detection limits for both analytes (0.075 µg L-1 for 6-CN and 0.050 µg L-1 for 3-PBA) in a short preparation and analysis time. The method used small initial urine sample volume (2 mL), short extraction time (≈ 240 min for the batches of 32 samples) and instrumental analysis time (≈ 14 min) for both pesticide metabolites in a single run. This protocol could facilitate the assessment of population exposure metrics for these pesticides and their inclusion in health risk assessment. Graphical abstract.

Congenital anomalies in the offspring of occupationally exposed mothers: a systematic review and meta-analysis of studies using expert assessment for occupational exposures.

STUDY QUESTION: Is there an association between maternal occupational exposure to solvents, pesticides and metals as assessed by expert-based assessment and congenital anomalies in the offspring? SUMMARY ANSWER: There is an association between maternal occupational exposure to solvents and congenital anomalies in the offspring, including neural tube defects, congenital heart defects and orofacial clefts. WHAT IS KNOWN ALREADY: One important environmental risk factor for development of congenital anomalies is maternal occupational exposure to chemicals in the workplace prior to and during pregnancy. A number of studies have assessed the association with often conflicting results, possibly due to different occupational exposure assessing methods. STUDY DESIGN, SIZE, DURATION: For this systematic review with meta-analysis, the search terms included maternal occupation, exposure, congenital anomalies and offspring. Electronic databases MEDLINE and EMBASE were searched for English studies up to October 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two reviewers independently screened all citations identified by the search. Case-control studies and cohort studies were included if (I) they reported on the association between maternal occupational exposure to solvents, pesticides or metals and congenital anomalies, and (II) assessment of occupational exposure was performed by experts. Data on study characteristics, confounders and odds ratios (ORs) were extracted from the included studies for four subgroups of congenital anomalies. Methodological quality was assessed using the Newcastle-Ottawa Scale. In the meta-analysis, random effects models were used to pool estimates. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 2806 titles and abstracts and 176 full text papers were screened. Finally, 28 studies met the selection criteria, and 27 studies could be included in the meta-analysis. Our meta-analysis showed that maternal occupational exposure to solvents was associated with neural tube defects (OR: 1.51, 95%CI: 1.09-2.09) and congenital heart defects (OR: 1.31, 95%CI:1.06-1.63) in the offspring. Also maternal occupational exposure to glycol ethers, a subgroup of solvents, was associated with neural tube defects (OR: 1.93, 95%CI: 1.17-3.18) and orofacial clefts (OR: 1.95, 95%CI: 1.38-2.75) in the offspring. Only one study investigated the association between maternal occupational exposure to solvents and hypospadias and found an association (OR: 3.63, 95%CI: 1.94-7.17). Results of the included studies were consistent. In our meta-analysis, we found no associations between occupational exposure to pesticides or metals and congenital anomalies in the offspring. LIMITATIONS, REASONS FOR CAUTION: A limited number of studies was included, which made it impossible to calculate pooled estimates for all congenital anomalies, analyse individual chemicals or calculate exposure-response relations. Bias could have been introduced because not all included studies corrected for potentially confounding factors. WIDER IMPLICATIONS OF THE FINDINGS: Employers and female employees should be aware of the possible teratogenic effects of solvent exposure at the workplace. Therefore, is it important that clinicians and occupational health specialist provide women with preconception advice on occupational solvent exposure, to reduce the congenital anomaly risk. STUDY FUNDING/COMPETING INTEREST(S): NSp was paid by the Graduate School of Medical Sciences (MD/PhD program), UMCG, Groningen, the Netherlands. EUROCAT Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. There are no competing interests. REGISTRATION NUMBER: CRD42017053943.

Combined use of a modifier gas generator, analyte protectants and multiple internal standards for effective and robust compensation of matrix effects in gas chromatographic analysis of pesticides.

In the analysis of pesticides performed with gas chromatography, the quantitative performance of measurements can be severely compromised by phenomena known as matrix effects. In seeking a solution to the problem of matrix effects, the application of a modifier gas generator (MGG) was investigated in this study, together with analyte protectants and multiple internal standards. Ethylene glycol (EG) was used as modifier gas and matrix effects in GCMS analysis were then evaluated by using the extracts of various food commodities. MGG was used in combination with other known methods of matrix effect compensation and its performance in reducing matrix effects tested. We have found that by combining MGG with conventional analyte protectants, matrix effects were substantially reduced for most of pesticides. Use of EG was especially effective for organophosphate pesticides and those with amino groups. Using this approach, the shortcomings of conventional analyte protectants were remedied. Although neither EG nor analyte protectants could sufficiently reduce the matrix effects for certain classes of pesticides, this limitation could be overcome with the use of multiple internal standards (IS) in the analysis. Finally, it was shown that the method we developed could achieve better analytical performance than the matrix-matched calibration method. Our method was robust with respect to the variation of food matrix components, so its application to real-world analyses would be practical and promising.

[Current status of pesticides against ticks].

Ticks can spread a variety of diseases and cause serious damage to animal husbandry. However, the existing insecticide and vaccine control methods have some disadvantages. In this paper, we review the research status of tick pesticides, including the chemical pesticides and non-chemical pesticides (Chinese herbal medicine, nanometer material, virus, fungus and bacterium pesticides), and analyze the disadvantages of the existing researches on pesticides against ticks, in order to provide a theoretical reference for establishing high-efficient and safety tick control methods.

Perspective: regulation of pest and disease control strategies and why (many) economists are concerned.

Pests and diseases are a continuous challenge in agriculture production. A wide range of control strategies have been and will continue to be developed. New control strategies are in almost all countries around the world assessed prior to approval for use in farmers' fields. This is rightly so to avoid and even reduce negative effects for human health and the environment. Over the past decades the approval processes have become increasingly politicized resulting in an increase in the direct approval costs and the length in approval time without increasing the safety of the final product. This reduces the development of control strategies and often has negative human health and environmental effects. Possibilities exist for improvements. They include reducing approval costs and approval time by streamlining the approval process and substituting approval requirements by strengthening ex-post liability. © 2018 Society of Chemical Industry.

Compensation for matrix effects in GC analysis of pesticides by using cucumber extract.

Matrix effects (MEs) can adversely affect quantification in pesticide residue analysis using GC. Analyte protectants (APs) can effectively interact with and mask active sites in the GC system, and are added individually or in combination to sample extracts and calibration solutions to minimize errors related to MEs. Unfortunately, APs cannot sufficiently compensate for MEs in all cases. Plant extracts, containing a broad range of natural compounds with AP properties, can also be used for this purpose. In this study, the applicability of cucumber extract as a natural AP mixture was investigated both alone and in combination with traditional APs. Extracts of two selected difficult matrices (onion and garlic) were prepared according to the citrate-buffered QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure. ME values of 40 representative GC-amenable pesticides were compared when calibrating against standards in pure solvent and in cucumber extract, with and without the addition of APs. Using a GC system with a contaminated inlet liner, the use of a cucumber-based calibration solution decreased MEs remarkably. The combination of APs with cucumber raw extract further decreased MEs, resulting in more than 85% of the tested pesticides showing ≤ 10% ME in onion and ≤ 20% ME in garlic. These results demonstrate that the preparation of calibration standards based on cucumber extracts (with or without the addition of APs) is a very useful and practical approach to compensate for MEs in pesticide residue analysis using QuEChERS and GC-MS/MS. The use of various internal standards is furthermore critically discussed.

Assessing the effects of field-relevant pesticide mixtures for their compliance with the concentration addition model - An experimental approach with Daphnia magna.

The environmental risk assessment of pesticides is mainly performed on individual active ingredients. In surface waters within the agricultural landscape, however, contamination is usually characterized by complex pesticide mixtures. To estimate the joint effects caused by these complex mixtures, mathematical models have been proposed. Among these, the model of concentration addition (CA) is suggested as default model for the risk assessment of chemical mixtures as it is considered protective for mixtures composed of similar and dissimilar acting substances. Here we assessed the suitability of CA predictions for seven field relevant pesticide mixtures using acute (immobility) and chronic (reproduction) responses of the standard test species Daphnia magna. Pesticide mixtures indicated largely additive or less than additive effects when using CA model predictions as a reference. Moreover, we revealed that deviations from CA predictions are lower for chronic (up to 3.2-fold) relative to acute (up to 7.2-fold) response variables. Additionally, CA predictions were in general more accurate for complex mixtures relative to those composed of only a few pesticides. Thus, this study suggests CA models as largely protective for the risk assessment of pesticide mixtures justifying its use as default model. At the same time, extrapolating conclusions about the joint effects of pesticides from acute to chronic responses is uncertain, due to partly large discrepancies with regards to the deviation of model prediction and observed effects between exposure scenarios.

Introducing relative potency quotient approach associated with probabilistic cumulative risk assessment to derive soil standards for pesticide mixtures.

Children can be exposed to organophosphate and carbamate mixtures, which pose additive health effects via soil exposure. However, only 23 countries have soil standard values for organophosphate and carbamate pesticides, and most regulatory jurisdictions do not consider the cumulative exposure. This study derived proposed soil standards for organophosphates and carbamates by introducing the relative potency quotient approach (RPQ). The probabilistic cumulative risk assessment was also applied to evaluate current soil standards of pesticide mixtures. The U.S. Environmental Protection Agency (EPA) have soil standards of 19 organophosphates and five carbamates. However, these standards cannot protect population health via chronic exposure in conservative and semi-conservative scenarios based on the probabilistic risk assessment because the U.S.EPA simplified the regulatory process for the cumulative exposure to pesticide mixtures and omitted the soil allocation factor, which should be set for aggregate exposure. The analysis of proposed soil standards developed by the RPQ approach indicates that some human behavior variables, such as soil intake rate and exposure duration, have stronger impacts on the proposed soil standards than human biometric variables like body weight. This study may be helpful to develop regulatory standards and a framework for pesticide mixtures having additive health effects.

Why Regulators Lost Track and Control of Pesticide Risks: Lessons From the Case of Glyphosate-Based Herbicides and Genetically Engineered-Crop Technology.

PURPOSE OF REVIEW: The approval of genetically engineered (GE) crops in the late 1990s triggered dramatic changes in corn, soybean, and cotton pest management systems, as well as complex, novel regulatory challenges. Lessons learned are reviewed and solutions described. RECENT FINDINGS: Government-imposed resistance management provisions can work and adapt to changing circumstances, but within the private sector, pressures to gain and hold market share have thus far trumped the widely recognized need for resistance management. Risks arising from the use of formulated pesticides often exceed by a wide margin those in regulatory risk assessments based on data derived from studies on nearly 100% pure active ingredients. Innovative policy changes are needed in four problem areas: excessive faith in the accuracy of pre-market risk assessments and regulatory thresholds; post-approval monitoring of actual impacts; risk arising from formulated pesticides, rather than just pure active ingredient; challenges inherent in assessing and mitigating the combined impacts of all GE traits and associated pesticides on agroecosystems, as opposed to each trait or pesticide alone; and, tools to deal with failing pest management systems.

Persistent organochlorine pesticides in aquatic environments and fishes in Taiwan and their risk assessment.

Organochlorine pesticides (OCPs) are ubiquitous contaminants with high bioaccumulation and persistence in the environment; they can have adverse effects in humans and animals. This study examined residual concentrations in water, sediments, and fishes as well as the association between the health risks of OCPs and fish consumption in the Taiwanese population. Various water and sediment samples from Taiwanese aquaculture and fish samples from different sources were collected and analyzed through gas chromatography tandem mass spectrometry to determine the concentrations of 20 OCPs, namely, aldrin; cis-chlordane; trans-chlordane; dieldrin; endrin; alpha-endosulfan; beta-endosulfan; heptachlor; hexachlorobenzene; alpha-hexachlorocyclohexane; beta-hexachlorocyclohexane; lindane; mirex; pentachlorobenzene; o,p'-dichlorodiphenyltrichloroethane (DDT); p,p'-DDT; and DDT metabolites (o,p'-dichlorodiphenyldichloroethane [DDD]; p,p'-DDD; o,p'-dichlorodiphenyldichloroethylene [DDE]; and p,p'-DDE). None of the analyzed samples was positive for OCP contamination, suggesting no new input pollution from the land through washing into Taiwanese aquaculture environments. However, OCP residues were detected in fishes caught along the coast, namely, skipjack tuna and bigeye barracuda, and in imported fishes, such as codfish and salmon. DDT was the predominant pesticide. The contamination pattern of persistent organic pollutants was as follows: dieldrin > cis-chlordane > hexachlorobenzene, with average concentrations ranging from 0.09 to 2.74 ng/g. The risk was assessed in terms of the estimated daily intake (EDI) for potential adverse indices; the EDI of OCP residues was lower than 1% of the acceptable daily intake established by the Food and Agriculture Organization of the United Nations and World Health Organization. The assessed risk was negligible and considered to be at a safe level, suggesting no association between fish consumption and risks to human health in Taiwan. However, a continuous monitoring program for OCP residues in fishes is necessary to further assess the possible effects on human health.

[The flexibilization of the Brazilian legislation on pesticides and the risks to human health: analysis of Bill of Law 3,200/2015]. / A flexibilização da legislação brasileira de agrotóxicos e os riscos à saúde humana: análise do Projeto de Lei nº 3.200/2015.

This article aims to contribute to a reflection on pesticides, based on the Brazilian legal framework, from the perspective of protecting human health and the environment. This initiative is due to successive attempts to flexibilize the regulation of pesticides in Brazil, through bills of law in progress in the Brazilian National Congress. An analysis of Bill of Law 3,200/2015 was carried out. This bill of law represents a major setback to the legislative achievements for the regulation of pesticides, in order to alert to the risks to human health from exposure to these products and aggravated by other similar proposals.