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The adverse outcome pathway (AOP) framework serves as a practical tool for organising scientific knowledge that can be used to infer cause–effect relationships between stressor events and toxicity outcomes in intact organisms. However, a major challenge in the broader application of the AOP concept within regulatory toxicology is the development of a robust AOPs that can withstand peer review and acceptance. This is mainly due to the considerable amount of work required to substantiate the modular units of a complete AOP, which can take years from inception to completion. The methodology used here consisted of an initial assessment of a single chemical hazard using the Integrated Approach to Testing and Assessment (IATA) framework. An evidence‐based approach was then used to gather empirical evidence combining systematic literature review methods with expert knowledge to ensure the effectiveness of the AOP development methodology. The structured framework used assured transparency, objectivity and comprehensiveness, and included expert knowledge elicitation for the evaluation of key event relationships (KERs). This stepwise approach led to the development of an AOP that begins with binding of chemicals to Voltage Gate Sodium Channels (VGSC/Nav) during mammalian development leading to adverse consequences in neurodevelopment evidenced as deficits in cognitive functions. Disruption of the formation of precise neural circuits by alterations in VGSC kinetics during the perinatal stages of brain development may also underlie neurodevelopmental disorders. Gaps in our understanding include the specific critical developmental windows and the quantitative relationship of binding to VGSC and subsequent disruption and cognitive function. Despite the limited quantitative information at all KER levels, regulatory applications of this AOP for DNT assessment have been identified. [ABSTRACT FROM AUTHOR]

Acetamiprid is a pesticide active substance with insecticidal action whose approval was renewed by Commission Implementing Regulation (EU) 2018/113. In January 2022, the EFSA PPR Panel published a statement following a request from the European Commission to advise on human health or the environment based on new scientific evidence presented by France during the decision‐making phase. In July 2022, by means of a further mandate received from the European Commission, EFSA was requested to provide advice if new information and any other scientific evidence that has become available since the assessment conducted for the renewal in 2018 warrant re‐evaluation of (i) toxicological parameters used for the risk assessment of acetamiprid during the renewal process, including toxicological endpoints; (ii) the residue definition for acetamiprid in products of plant origin; and (iii) the safety of existing maximum residue levels (MRLs). Meanwhile, the applicant of acetamiprid in the EU submitted new toxicology studies regarding the toxicological profile of the metabolite IM‐2‐1. Furthermore, the European Commission was made aware that several recent publications in scientific literature were made available after the literature searches conducted by EFSA. As the new data could affect the advice that EFSA was expected to deliver through the 2022 mandate, EFSA was further requested to consider this information by means of a revised mandate received in September 2023. As regards re‐evaluation of point (i) in this statement, this was addressed by an EFSA Working Group integrating all the available evidence. The results of the weight of evidence indicated that there are major uncertainties in the body of evidence for the developmental neurotoxicity (DNT) properties of acetamiprid and further data are therefore needed to come to a more robust mechanistic understanding to enable appropriate hazard and risk assessment. In view of these uncertainties, the EFSA WG proposed to lower the acceptable daily intake (ADI) and acute reference dose (ARfD) from 0.025 to 0.005 mg/kg body weight (per day). A revised residue definition for risk assessment was proposed for leafy and fruit crops as sum of acetamiprid and N‐desmethyl‐acetamiprid (IM‐2‐1), expressed as acetamiprid. Regarding pulses/oilseeds, root crops and cereals, the new data received did not indicate a need to modify the existing residue definition for risk assessment, which therefore remains as parent acetamiprid. Regarding the residue definition for enforcement, the available data did not indicate a need to modify the existing definition because acetamiprid is still a sufficient marker of the residues in all crop groups. Considering the new health‐based guidance values derived in the present statement, a risk for consumer has been identified for 38 MRLs currently in place in the EU Regulation. Consequently, EFSA recommended to lower the existing MRLs for 38 commodities based on the assessment of fall‐back Good Agricultural Practices received within an ad hoc data call. Some fall‐back MRLs proposals require further risk management considerations. [ABSTRACT FROM AUTHOR]

In compliance with Article 43 of Regulation (EC) No 396/2005, EFSA received from the European Commission in 2020 a mandate to provide its reasoned opinion on the toxicological properties and maximum residue levels (MRLs) for the benzimidazole substances carbendazim and thiophanate‐methyl. Specifically, EFSA was asked to assess whether thiophanate‐methyl or carbendazim has clastogenic potential and, in case clastogenic potential can be excluded, to derive toxicological reference values necessary for consumer risk assessment and assessment of maximum residue levels (MRLs). Although these active substances are no longer authorised within the European Union, MRLs were established by the Codex Alimentarius Commission (codex maximum residue limits; CXLs), and import tolerances are in place. Based on the assessment of the available data, toxicological reference values and MRL proposals were derived and a consumer risk assessment was carried out. Some information required by the regulatory framework was found to be missing and a possible acute risk to consumers was identified. Hence, the consumer risk assessment was considered indicative only and all MRL proposals derived by EFSA still require further consideration by risk managers. In October 2022, to ensure that MRLs derived by EFSA in its assessment of 2021 are safe for consumers also in view of endocrine‐disrupting properties, EFSA was requested to carry out a follow‐up assessment taking into account the scientific criteria for identifying endocrine disruptors (ED). Based on the outcome of the assessment, the experts agreed that the reference values are also covering the concern related to the identified hazards indicative of endocrine disruption for thiophanate‐methyl. No further considerations on the impact of the ED assessment on the current reference values were needed for carbendazim since the ED criteria are not met for this substance. Therefore, the risk assessment and the MRL recommendations derived in 2021 are confirmed. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance profenofos in view of the possible lowering of the MRL. EFSA investigated the origin of the current EU MRLs. Existing EU MRLs are based on Codex Maximum Residue Limits still in place or reflect temporary MRLs set from monitoring data. EFSA performed an indicative chronic and acute dietary risk assessment for the list of MRLs to allow risk managers to take the appropriate decisions. For some commodities, further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance chlorfenapyr in view of the possible lowering of the MRL set for tea. This current EU MRL is based on an import tolerance established in 2007. EFSA reviewed the toxicological data assessed by other scientific bodies, proposing toxicological reference values to be used for an indicative risk assessment, noting that the values are affected by additional, non‐standard uncertainties. According to the indicative chronic and acute dietary risk assessment the existing MRL for tea does not pose an unacceptable risk for consumers. Further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance dicofol in view of the possible lowering of the MRL. EFSA investigated the origin of the current EU MRLs. All existing EU MRLs reflect previously authorised uses in the EU or are based on obsolete Codex Maximum Residue Limits. Furthermore, in view of the limitations of the toxicological dataset and related uncertainties, the existing toxicological reference values derived at the EU level cannot be confirmed for dicofol. EFSA therefore proposed lowering all existing EU MRLs for dicofol to the limit of quantification. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance fenarimol in view of the possible lowering of the MRLs. EFSA investigated the origin of the current EU MRLs. For existing EU MRLs that reflect previously authorised uses in the EU, or that are based on obsolete Codex maximum residue limits, or import tolerances that are not required any longer, EFSA proposed the lowering to the limit of quantification. EFSA performed a chronic and acute dietary risk assessment for the revised list of MRLs to allow risk managers to take the appropriate decisions. For some commodities, further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance endosulfan in view of the possible lowering of the MRLs. EFSA investigated the origin of the current EU MRLs. For existing EU MRLs that reflect previously authorised uses in the EU, or that are based on obsolete Codex maximum residue limits, or import tolerances that are not required any longer, EFSA proposed the lowering to the limit of quantification or to an alternative MRL. EFSA performed an indicative chronic and acute dietary risk assessment for the revised list of MRLs to allow risk managers to take the appropriate decisions. For all commodities, further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substances azocyclotin and cyhexatin in view of the possible lowering of these MRLs. EFSA investigated the origin of the current EU MRLs. For existing EU MRLs that reflect previously authorised uses in the EU, or that are based on obsolete Codex Maximum Residue Limits, or import tolerances that are not required any longer, EFSA proposed the lowering to the limit of quantification. EFSA performed an indicative chronic and acute dietary risk assessment for the revised list of MRLs to allow risk managers to take the appropriate decisions. For some commodities under assessment, further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

In accordance with Article 43 of Regulation (EC) 396/2005, EFSA received a request from the European Commission to review the existing maximum residue levels (MRLs) for the non‐approved active substance bifenthrin in view of the possible lowering of the MRLs. EFSA investigated the origin of the current EU MRLs. For existing EU MRLs that reflect previously authorised uses in the EU, or that are based on obsolete Codex maximum residue limits, or import tolerances that are not required any longer, EFSA proposed the lowering to the limit of quantification or to an alternative MRL. EFSA performed an indicative chronic and acute dietary risk assessment for the revised list of MRLs to allow risk managers to take the appropriate decisions. For some commodities, further risk management discussions are required to decide which of the risk management options proposed by EFSA should be implemented in the EU MRL legislation. [ABSTRACT FROM AUTHOR]

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the group of pesticide active substances cypermethrins. To assess the occurrence of cypermethrin, alpha‐cypermethrin, zeta‐cypermethrin, beta‐cypermethrin residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Regulation (EC) No 1107/2009, the MRLs established by the Codex Alimentarius Commission (codex maximum residue limits; CXLs) for cypermethrin, alpha‐cypermethrin and zeta‐cypermethrin as well as the European authorisations and import tolerances reported by Member States and the UK (including the supporting residues data) for cypermethrin and zeta‐cypermethrin. The toxicological profile of zeta‐cypermethrin was also assessed. Based on the assessment of the available data, MRL proposals were derived, and a consumer risk assessment was carried out. Some information required by the regulatory framework was missing and a possible chronic/acute risk to consumer was identified. Hence, the consumer risk assessment is considered indicative only, all MRL proposals derived by EFSA still require further consideration by risk managers and measures for reduction of the consumer exposure should also be considered. [ABSTRACT FROM AUTHOR]

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide dithianon. To assess the occurrence of dithianon residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Commission Regulation (EC) No 33/2008, the MRLs established by the Codex Alimentarius Commission as well as the European authorisations reported by Member States and the UK, including the supporting residues data. Given that a data gap as regards the magnitude of residues of the metabolites 1,4‐naphthoquinone and phthalic acid was identified in the peer review for dithianon in light of confirmatory data, the toxicological profile of these metabolites was also assessed in the framework of the Article 12 MRL review. Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was missing. In particular, it is highlighted that the toxicological reference values derived for the metabolite 1,4‐naphthoquinone are provisional only, pending a conclusion on the mutagenicity potential. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers. [ABSTRACT FROM AUTHOR]

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicant Syngenta France SAS submitted a request to the competent national authority in France to modify the existing maximum residue level (MRL) for the active substance sedaxane in potatoes. The data submitted in support of the request were found to be sufficient to derive an MRL proposal for potatoes. Adequate analytical methods for enforcement are available to control the residues of sedaxane on the commodity under consideration at the validated limit of quantification (LOQ) of 0.01 mg/kg. Based on the risk assessment results, EFSA concluded that the short‐term and long‐term intake of residues resulting from the use of sedaxane according to the intended agricultural practice is unlikely to present a risk to consumer health. [ABSTRACT FROM AUTHOR]

The conclusions of the EFSA following the peer review of the initial risk assessment carried out by the competent authority of the rapporteur Member State, Spain, for the pesticide active substance thiabendazole are reported. The context of the peer review was that requested by the European Commission following the submission and evaluation of confirmatory information with regard to the endocrine disruption potential of the substance. The conclusions were reached on the basis of the evaluation of the representative uses of thiabendazole as a fungicide on seed potato, apple and pear and citrus. Assessments not finalised together with the missing information identified as being required by the mandate are listed. Concerns are identified. [ABSTRACT FROM AUTHOR]

In accordance with Art. 31(1) of Regulation (EC) No 178/2002, the Commission asked EFSA to provide a scientific review on the BfR opinion on the 'Health risk assessment of ethylene oxide residues in sesame seeds' (Opinion No 024/2021) regarding the toxicity of 2‐chloroethanol. In addition, EFSA was asked to clarify under which circumstances the use of the MOE approach is considered appropriate. Based on the information available to EFSA, i.e. the studies assessed in the frame of the BfR opinion and additional data provided by stakeholders not assessed by BfR, EFSA considers the genotoxicity of 2‐chloroethanol as inconclusive. On this basis, EFSA would not recommend setting reference points for risk assessment or health‐based guidance values until the genotoxic potential of 2‐chloroethanol is clarified. EFSA therefore recommends performing new in vitro gene mutation and in vitro micronucleus tests with 2‐chloroethanol following the recommendations of the most recent OECD technical guidelines to clarify its genotoxic potential. If the result of any of the test is positive, the recommendations of the EFSA Scientific Committee (2011) should be followed. If the genotoxic potential of 2‐chloroethanol is finally clarified and overall negative, EFSA would recommend setting the reference point for deriving health‐based guidance values based on existing toxicity studies on 2‐chloroethanol. [ABSTRACT FROM AUTHOR]

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessment carried out by the competent authority of the rapporteur Member State Sweden, for the pesticide active substance propyzamide are reported. The context of the peer review was that requested by the European Commission following the submission and evaluation of confirmatory information in the areas of mammalian toxicology and residues. The conclusions were reached on the basis of the evaluation of the representative uses of propyzamide as an herbicide on lettuce and winter oilseed rape. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and/or literature in the dossier peer reviewed, are presented. Concerns are identified. [ABSTRACT FROM AUTHOR]

The conclusions of the EFSA following the peer review of the initial risk assessment carried out by the competent authority of the rapporteur Member State, France, for the pesticide active substance acibenzolar-S-methyl are reported. The context of the peer review was that requested by the European Commission following the submission and evaluation of confirmatory information with regard to the endocrine disruption potential of the substance. The conclusions were reached on the basis of the evaluation of the representative uses of acibenzolar-S-methyl as a plant activator on pome fruit, tomato and tobacco. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Assessments not finalised together with the missing information identified as being required by the regulatory framework are listed. [ABSTRACT FROM AUTHOR]

A retrospective cumulative risk assessment of dietary exposure to pesticide residues was conducted for chronic inhibition of acetylcholinesterase. The pesticides considered in this assessment were identified and characterised in a previous scientific report on the establishment of cumulative assessment groups of pesticides for their effects on the nervous system. The exposure assessments used monitoring data collected by Member States under their official pesticide monitoring programmes in 2016, 2017 and 2018, and individual food consumption data from 10 populations of consumers from different countries and from different age groups. Exposure estimates were obtained by means of a two‐dimensional probabilistic model, which was implemented in SAS® software. The characterisation of cumulative risk was supported by an uncertainty analysis based on expert knowledge elicitation. For each of the 10 populations, it is concluded with varying degrees of certainty that cumulative exposure to pesticides contributing to the chronic inhibition of acetylcholinesterase does not exceed the threshold for regulatory consideration established by risk managers. [ABSTRACT FROM AUTHOR]

Phenylmethylsulfonyl fluoride (PMSF) is a protease andesteraseinhibitor that causes protection or potentiation/promotion of organophosphorusdelayed neuropathy (OPIDN) depending on whether it is dosed beforeor after an inducer of delayed neuropathy. The molecular target ofpromotion has not yet been identified. Kinetic data of esterase inhibitionwere first obtained for PMSF with a soluble chicken brain fractionand then analyzed using a kinetic model with a multienzymatic systemin which inhibition occurred with the simultaneous chemical hydrolysisof the inhibitor and ongoing inhibition (inhibition during the substratereaction). The best fitting model was a model with resistant fraction,Eα (28%), and two sensitive enzymatic entities, Eβ (61%)and Eγ (11%), with I50at 20 min of 70 and 447 μM,respectively. The estimated constant of the chemical hydrolysis ofPMSF was kh= 0.23 min–1. Eα,which is sensitive to mipafox and resistant to PMSF, became less sensitiveto mipafox when the preparation was preincubated with PMSF. Its EαI50(30 min) of mipafox increased with the PMSF concentrationused to preincubate it. Eγ is sensitive to both PMSF and mipafox,and after preincubation with PMSF, Eγ became less sensitiveto mipafox and was totally resistant after preincubation with 10 μMPMSF or more. The sensitivity of Eα to paraoxon (I5030 min from 9 to 11 nM) diminished after PMSF preincubation (I5030 min 185 nM) and showed no spontaneous reactivation capacity.The nature of these interactions is unknown but might be due to covalentbinding at sites other than the substrate catalytic center. Such interactionsshould be considered to interpret the potentiation/promotion phenomenonof PMSF and to understand the effects of multiple exposures to chemicals. [ABSTRACT FROM AUTHOR]

Protective mechanism against organophosphorus compounds (OPs) toxicity are mainly based in molecular processes frequently divided conceptually in (A) catalytic and (B) non-catalytic bio-scavengers. Modified natural proteins and small molecules have been developed for applying in therapy and protection. The catalytic ones are mainly associate to the classical concept of A-esterases (phosphotriesterases, PTEs, i.e. paraoxonase); they hydrolyze carboxylesters and OPs by a divalent cation dependent mechanism. The non-catalytic scavengers are mainly associated to covalent binding to proteins, especially B-esterases with a serine or tyrosine residue, which hydrolyzes carboxylesters. However, if an OP is bound (organophosphorylation), its represents an enzymatic inhibition in some cases considered "the target" of toxicity or initial molecular event (IME) in their mode of action developing toxicity (adverse output pathway, AOP). The binding to proteins also represents a sequestration avoiding the OP interaction to other protein. However, there are protein binding OPs (non-catalytic bioscavengers) which can be slowly dephosphorylated, having a role as catalytic scavenger. A proportion of B-esterase activity in serum and brain shows reversible inhibition and their protective role just in situ in the target tissue of toxicity need to be investigated. Serum albumin is other example of B-esterase mainly thorough a tyrosine residue; its role in detoxication have been demonstrated and adducts applied as biomarker of exposure. Moreover, for a specific phosphoramidate family hydrolysis capacity may be enhanced by copper, probably by a mechanism not related with its B-esterase activity. Therefore, we have examples in the borderline between non-catalytic and catalytic scavengers. [ABSTRACT FROM AUTHOR]

The toxicity of organophosphorus compounds (OPs) cannot be explained only by action on acetylcholinesterase or neuropathy target esterase (NTE). A fraction of the membrane bound phenylvalerate esterase activity (PVase) is associated to NTE, the key initiating molecular event in the OP-induced delayed neuropathy (OPIDN). An enzymatic fraction in chicken brain soluble PVase has been reported to be due to a butyrylcholinesterase protein, and we suggested that this enzymatic fraction could be related to the mode of action of the potentiation/promotion phenomenon of the OPIDN. We showed that human butyrylcholinesterase (hBuChE) shows PVase activity. Mipafox, iso-OMPA or PMSF inhibited both activities with similar kinetic constants for both activities. Moreover, the substrates acethylthiocholine and phenyl valerate showed competition in their activities. The results suggest that both activities are related to the same active center. This work studies in depth the kinetic interactions between phenyl valerate and acetylthiocholine in human butyrylcholinesterase, showing that the interactions are different to the competitive model of substrates according to the Michaelis-Menten reaction. The approach introduced in this work suggests that other site could be involved in the interaction with phenyl valerate. In addition, we have observed that human acetylcholinesterase has also phenyl valerate esterase activity, but with lower activity than human butyrylcholinesterase. The level of phenylvalerate esterase activity in cholinesterases depends on the species and the type of cholinesterase. Further evaluation of the molecular interactions is under study. [ABSTRACT FROM AUTHOR]

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State France and co-rapporteur Member State Spain for the pesticide active substance fludioxonil are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative use of fludioxonil as a fungicide on wheat, oats, grapes, pome fruit and strawberry. The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified., (© 2024 European Food Safety Authority. EFSA Journal published by Wiley‐VCH GmbH on behalf of European Food Safety Authority.)

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, The Netherlands for the pesticide active substance bixlozone are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of bixlozone as an herbicide on winter cereals (wheat and barley), winter oilseed rape and maize via soil broadcast spray application in field. The reliable endpoints, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified., (© 2024 European Food Safety Authority. EFSA Journal published by Wiley‐VCH GmbH on behalf of European Food Safety Authority.)