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In Europe, agencies and official organizations involved in the pesticide control such as the EFSA, ECHA, JRC and ECETOC or even the OECD are pointing out that the software tools based on quantitative structure relationship models, i.e. QSAR and QSPR, have a huge potential to improve the pesticide risk assessment process. In this sense, these non-animal test methods can promote the competitiveness of agriculture in this region: the consumer safety is increased with them due to the possibility of perform an overall better risk assessment of the degradation products and metabolites from pesticides. However, the use of theses computational-based (in silico) tools must be much more systematised and harmonised, improving their validation and including case studies to test them. To open databases, incorporating critical data in an orderly manner for building the models, becomes also necessary. Moreover, quantum chemistry through the Density Functional Theory should be promoted as tool for calculation of quantum descriptors, especially for the study of similar compounds with the same carbon skeleton but differing substitution patterns, e.g. isomers. [ABSTRACT FROM AUTHOR]

According to EU guidance SANCO/7525/VI/95 Rev. 10.3, residue data extrapolation from a surrogate major crop to a minor crop can be used for setting maximum residue levels (MRLs) with a reduced number of residue trials and representative selected pesticides. In this work, a QuEChERS method (citrate-buffered version and PSA with MgSO 4 clean-up) and LC-ESI-MS/MS for the determination of boscalid, pyraclostrobin, fludioxonil, fluopyram and tebuconazole in persimmon was developed and validated according to EU Commission guidelines and afterwards used for the determination of residues in four field trials. Residue levels at harvest for each pesticide ranged between 0.347 and 0.028 mg/kg. After comparing EFSA residue data on apples, as the surrogate major crop, and conducting a consumer risk assessment, a proposal of residue data extrapolation to set MRLs in persimmons was performed. The results showed that pesticide residues in persimmons at harvest were consistently lower than residues in apples when substances were applied according to the same critical GAP. MRLs were set at 0.5 mg/kg for fludioxonil, 0.6 mg/kg for boscalid, 0.3 mg/kg for tebuconazole, 0.4 mg/kg for fluopyran and 0.3 mg/kg for pyraclostrobin. The ratio of the MRLs for apple/persimmon varied between 2.5 for boscalid and 1.25 for fluopyram, suggesting that residue extrapolation can be feasible, promoting the process of pesticide registration for minor crops and the settlement of MRL.

The European market for pesticides is currently legislated through the well-developed Regulation (EC) No. 1107/2009. This regulation promotes the competitiveness of European agriculture, recognizing the necessity of safe pesticides for human and animal health and the environment to protect crops against pests, diseases and weeds. In this sense, nanotechnology can provide a tremendous opportunity to achieve a more rational use of pesticides. However, the lack of information regarding nanopesticides and their fate and behavior in the environment and their effects on human and animal health is inhibiting rapid nanopesticide incorporation into European Union agriculture. This review analyzes the recent state of knowledge on nanopesticide risk assessment, highlighting the challenges that need to be overcame to accelerate the arrival of these new tools for plant protection to European agricultural professionals. Novel nano-Quantitative Structure-Activity/Structure-Property Relationship (nano-QSAR/QSPR) tools for risk assessment are analyzed, including modeling methods and validation procedures towards the potential of these computational instruments to meet the current requirements for authorization of nanoformulations. Future trends on these issues, of pressing importance within the context of the current European pesticide legislative framework, are also discussed. Standard protocols to make high-quality and well-described datasets for the series of related but differently sized nanoparticles/nanopesticides are required., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Assessment of two buffered QuEChERS (quick, easy, cheap, effective, rugged, and safe) versions (i.e., citrate and acetate) modified by including methanol to recover the residues of three cyclohexanedione oxime (CHD) herbicides and three of their byproducts from agricultural soil was performed. In this context, a full second-order face-centered factorial experimental design was developed to quantify the influences of the main five variables (i.e., extraction time, water content, soil weight, and extraction solvent volume and composition) on the target compound recoveries. The fitting equations satisfactorily described the extraction process behavior. The mathematical models also showed the most influencing independent variables (i.e., extraction solvent composition and soil weight). Handling simpler expressions was possible with the acetate QuEChERS but not with the citrate QuEChERS. The recoveries of the CHD residues were close to 100% after performing the extraction under suitable conditions. Furthermore, dispersive solid-phase extraction (dSPE) clean-up steps were assessed to reduce the matrix effect in mass spectrometry. In this sense, the citrate QuEChERS in combination with the PSA + C18 clean-up step was the best option for the extraction of CHD residues.

The photochemical fate of the herbicide clethodim in natural waters was investigated under simulated and natural sunlight radiation. This herbicide exhibited a rapid degradation rate in simulated aquatic environment with half-lives ranged from 27.9min to 4.6h. The commercial formulation of clethodim showed a faster degradation with half-lives from 19.3min to 1.4h. It has also been demonstrated that the photolytic behavior of clethodim was affected by the water composition and the radiation intensity. Nine major photoproducts were identified and their distribution was dependent on the experimental conditions. Photodegraded solutions of clethodim were shown to be more toxic to the bacteria Vibrio fischeri than the herbicide itself, reaching the maximum toxicity when the herbicide is completely degraded. QSAR analysis of the fate, ecotoxicological and physicochemical endpoints of the degradation products provided positive alerts for several identified by-products. Environmental fate and transport estimates showed that all photoproducts, unlike the active substance, are potential leachers. Moreover, predicted vapor pressures suggested that dermal contact and ingestion are the most probable exposure routes for workers and general population to both clethodim and its photoproducts. These results highlight the importance of the degradation products in attaining a complete knowledge of the fate and behavior of an herbicide in the environment. To our knowledge, this is the first study to report a detailed QSAR study on clethodim photoproducts under environmental conditions. These results provide a very valuable information that will guide further experimental studies leading to a better pesticide risk assessment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The scientific community and regulatory bodies worldwide, currently promote the development of non-experimental tests that produce reliable data for pesticide risk assessment. The use of standard quantum chemistry methods could allow the development of tools to perform a first screening of compounds to be considered for the experimental studies, improving the risk assessment. This fact results in a better distribution of resources and in better planning, allowing a more exhaustive study of the pesticides and their metabolic products. The current paper explores the potential of quantum chemistry in modelling toxicity and environmental behaviour of pesticides and their by-products by using electronic descriptors obtained computationally. Quantum chemistry has potential to estimate the physico-chemical properties of pesticides, including certain chemical reaction mechanisms and their degradation pathways, allowing modelling of the environmental behaviour of both pesticides and their by-products. In this sense, theoretical methods can contribute to performing a more focused risk assessment of pesticides used in the market, and may lead to higher quality and safer agricultural products. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)

Photolysis is an important route for the abiotic degradation of many pesticides. However, the knowledge of the photolytic behaviour of these compounds and their commercial formulations under environmentally-relevant conditions are limited. The present study investigated the importance of photochemical processes on the persistence and fate of the herbicide sethoxydim and its commercial formulation Poast ® in aqueous media. Moreover, the effect of important natural water substances (nitrate, calcium, and ferric ions) on the photolysis of the herbicide was also studied. The results showed that additives existing in the commercial formulation Poast ® accelerated the rate of photolysis of sethoxydim by a factor of 3. On the contrary, the presence of nitrate and calcium ions had no effect on the photodegradation rate while ferric ions resulted in an important decrease in the half-life of sethoxydim possibly due to the formation of a complex. Different transformation products were identified in the course of sethoxydim irradiation and the effect of experimental conditions on their concentrations was investigated. Finally, Microtox ® test revealed that aqueous solutions of sethoxydim photoproducts increased the toxicity to the bacteria Vibrio fischeri., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

An accurate, simple and rapid liquid chromatography mass spectrometry method for the determination of organic acids in peach fruit has been developed. Direct injection and sample clean-up with a mixed-mode sorbent was compared. The best results for the determination of gluconic, oxalic, malic, citric and fumaric acids were obtained with only a simple dilution and filtration step, and nylon filters should be avoided since some organic acids are retained by them. It is the first time that gluconic acid has been determined in peach fruit. Different parameters involved in the separation and detection process have been optimized. Since matrix effects were observed in the peach commodity, organic acids were quantified by the standard addition method. All validation parameters of the method were found acceptable of all organic acids. Finally, the method was successfully applied to the analysis of samples of peach from two cultivars., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The photochemical fate of sethoxydim herbicide in water was studied under simulated sunlight radiation (Suntest apparatus). This compound exhibited a rapid degradation rate in water with a half-life of approximately 1h, which is in accordance with the high calculated value of the quantum yield (Φ=0.26). Consequently, the photolysis of sethoxydim should be considered as an efficient route of sethoxydim removal in aqueous media. During the photodegradation studies, ten by-products were detected, and their identification was accomplished using high-performance liquid chromatography (HPLC) coupled with quadrupole time-of-flight mass spectrometry (Qtof) and electrospray ionization in positive mode (ESI+). A detailed and exhaustive study of the mass spectra of the precursor ions and their MS/MS fragmentation patterns allowed for their identification. The photodegradation products resulted from the cleavage and isomerization of the NO bond of the oxime, oxidation of the sulfur atom, oxidative CS bond cleavage and Beckmann rearrangement followed by intramolecular cyclization. Additionally, the reactive species involved and a plausible mechanism for the photodegradation of sethoxydim in water are discussed. Finally, based on the identified products, a rational pathway for the photodegradation of sethoxydim in water is proposed., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: The European Pesticide Regulation (EC) No. 1107/2009 encourages the use of less harmful active substances. Two main concerns involve the application of cut-off criteria for pesticides without losing tools for future agriculture (especially for minor uses) and the implementation of zonal evaluations. Biopesticides are considered to have lower risks than synthetic pesticides; consequently, there is strong interest for their use in integrated pest management practices., Results: This paper provides an analysis of the current European situation, starting with the first attempts to regulate the use of plant protection products and focusing on the implications of the new legislative criteria for biopesticides., Conclusion: It is important to be aware that biopesticides are still pesticides and fall under the same regulations as their synthetic counterparts. Although manufacturers are still reluctant to commit to such alternatives due to difficulties with approval and registration, biopesticides could be alternatives for traditional plant protection products, either as a base for the synthesis of new products or integrated with traditional plant protection products. In addition, biopesticides have to be used only as indicated on the label, which provides critical information about how to safely handle and use plant protection products., (© 2013 Society of Chemical Industry.)