Finding synergies for 3Rs - Toxicokinetics and read-across: Report from an EPAA partners' Forum.

The European Partnership for Alternative Approaches to Animal Testing (EPAA) convened a Partners' Forum Toxicokinetics and Read-Across to provide an overview on research activities to develop in vitro toxicokinetics methods and physiologically-based kinetic (PBK) models and to find synergies to enhance use of toxicokinetic data to strengthen read-across. Currently, lacking toxicokinetic data often prevent the application of read-across. Preferably, toxicokinetic data should be generated using in vitro and in silico tools and anchored towards human relevance. In certain sectors, PBK modelling is being used for risk assessment, but less so in others. Specific activities were identified to facilitate the use of in vitro and in silico toxicokinetic data to support read-across: The collation of available tools indicating the parameters and applicability domains covered; endpoint-specific guidance on toxicokinetics parameters required for read-across; case studies exemplifying how toxicokinetic data help support read-across. Activities to enhance the scientific robustness of read-across include the further user-friendly combination of read-across tools and formal guidance by the authorities specifying the minimum information requirements to justify read-across for a given toxicity endpoint. The EPAA was invited to continue dissemination activities and to explore possibilities to collate a contemporaneous list of open toxicokinetics tools that assist risk assessment.

Adverse outcome pathway development from protein alkylation to liver fibrosis.

In modern toxicology, substantial efforts are undertaken to develop alternative solutions for in vivo toxicity testing. The adverse outcome pathway (AOP) concept could facilitate knowledge-based safety assessment of chemicals that does not rely exclusively on in vivo toxicity testing. The construction of an AOP is based on understanding toxicological processes at different levels of biological organisation. Here, we present the developed AOP for liver fibrosis and demonstrate a linkage between hepatic injury caused by chemical protein alkylation and the formation of liver fibrosis, supported by coherent and consistent scientific data. This long-term process, in which inflammation, tissue destruction, and repair occur simultaneously, results from the complex interplay between various hepatic cell types, receptors, and signalling pathways. Due to the complexity of the process, an adequate liver fibrosis cell model for in vitro evaluation of a chemical's fibrogenic potential is not yet available. Liver fibrosis poses an important human health issue that is also relevant for regulatory purposes. An AOP described with enough mechanistic detail might support chemical risk assessment by indicating early markers for downstream events and thus facilitating the development of an in vitro testing strategy. With this work, we demonstrate how the AOP framework can support the assembly and coherent display of distributed mechanistic information from the literature to support the use of alternative approaches for prediction of toxicity. This AOP was developed according to the guidance document on developing and assessing AOPs and its supplement, the users' handbook, issued by the Organisation for Economic Co-operation and Development.

Measurement of ethyl glucuronide, ethyl sulphate and their ratio in the urine and serum of healthy volunteers after two doses of alcohol.

AIMS: Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are minor metabolites of ethanol, and their presence in urine provides a strong indication of recent alcohol administration. In this study, we performed a drinking experiment to investigate the kinetics of EtG and EtS formation and elimination after the administration of two doses of alcohol. METHODS: Nineteen volunteers provided urine and serum (only 18) after administration of 4 and 8 units of alcohol (1 unit corresponds to 10 ml or ∼8 g of pure ethanol). The analysis was performed using a validated ultra-performance liquid chromatography-mass spectrometry (UPLC(®)-MS/MS) method. RESULTS: After 4 units, the median EtG maximum concentration (C(max)) was 0.4 µg/ml and the interquartile range (0.3 µg/ml) in serum and 3.5 mg/h (1.2 mg/h) in urine and were reached (T(max)) after 2.0 h (0.8 h) and 3.0 h (1.0 h), respectively. EtS C(max) was 0.2 µg/ml (0.1 µg/ml) in serum and 1.3 mg/h (0.6 mg/h) in urine, and the corresponding T(max) were 1.0 h (1.0 h) and 2.0 h (0.5 h). After 8 units, EtG C(max) was 1.3 µg/ml (0.4 µg/ml) in serum and 10 mg/h (3.4 mg/h) in urine and was reached after 4.0 h (1.8 h) and 4.0 h (2.0 h), respectively. EtS C(max) was 0.6 µg/ml (0.1 µg/ml) in serum and 3.5 mg/h (1.1 mg/h) in urine, the corresponding T(max) were 3.0 h (1.0 h) and 3.0 h (1.0 h). The EtG/EtS ratio increased as a function of the time after alcohol administration in both serum and urine samples but to a lesser extent after 8 units than 4. CONCLUSION: These results correlate with values obtained in previous studies. T(max) of EtG and EtS increased between 4 and 8 units. The EtG:EtS ratio increased in the serum and urine samples of all volunteers as a function of time at least up to 4 h after alcohol administration.

Development of adverse outcome pathways relevant for the identification of substances having endocrine disruption properties Uterine adenocarcinoma as adverse outcome.

Development of adverse outcome pathways (AOPs) for uterine adenocarcinoma can provide a practical tool to implement the EFSA-ECHA Guidance (2018) for the identification of endocrine disruptors in the context of Regulations (EU) No 528/2012 and (EC) No 1107/2009. AOPs can give indications about the strength of the relationship between an adverse outcome (intended as a human health outcome) and chemicals (pesticides but not only) affecting the pathways. In this scientific opinion, the PPR Panel explored the development of AOPs for uterine adenocarcinoma. An evidence-based approach methodology was applied, and literature reviews were produced using a structured framework assuring transparency, objectivity, and comprehensiveness. Several AOPs were developed; these converged to a common critical node, that is increased estradiol availability in the uterus followed by estrogen receptor activation in the endometrium; therefore, a putative AOP network was considered. An uncertainty analysis and a probabilistic quantification of the weight of evidence have been carried out via expert knowledge elicitation for each set of MIEs/KEs/KERs included in individual AOPs. The collected data on the AOP network were evaluated qualitatively, whereas a quantitative uncertainty analysis for weight of the AOP network certainty has not been performed. Recommendations are provided, including exploring further the uncertainties identified in the AOPs and putative AOP network; further methodological developments for quantifying the certainty of the KERs and of the overall AOPs and AOP network; and investigating of NAMs applications in the context of some of the MIEs/KEs currently part of the putative AOP network developed.

Peer review of the pesticide risk assessment of the active substance Purpureocillium lilacinum strain PL11.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, the United Kingdom, for the pesticide active substance Purpureocillium lilacinum strain PL11 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 Purpureocillium lilacinum strain PL11 as nematicide on tomato, pepper, aubergine, cucumber, courgette, melon, watermelon, pumpkin (field and greenhouse applications). The reliable endpoints appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed.

Determination of in vitro metabolic hepatic clearance of valproic acid (VPA) and five analogues by UPLC-MS-QTOF, applicable in alternatives to animal testing.

Laboratory measurements of intrinsic clearance support the development of TK models, with potential relevance to weight of evidence toxicity assessments of xenobiotics, including read-across, the concept of predictive estimation by data extrapolation between chemicals of similar structure (analogues). In this work a procedure with analytical method for determination of in vitro hepatic metabolic clearance, relevant to biotransformation toxicokinetic (TK) modelling, is presented. Cryopreserved primary human hepatocytes represent a suitable cells, due to their biological characteristics, for providing an in vitro model for simulating in vivo metabolic clearance. The experimental part considered an adequate sequential time-frame for collecting samples and controls for all chemicals tested, including centrifugation and aliquoting of the corresponding fractions until the instrumental session. For the first time, in vitro hepatocyte intrinsic clearance was measured for six analogue test chemicals: valproic acid, 2-ethyl caproic acid, octanoic acid, valeric acid, 2-methyl butyric acid and 2-trans pentenoic acid, during incubated cell culture exposure up to 2 h or 3.5 h. The time dependence of any metabolism was determined from analysis of the supernatant at intervals using a new developed analytical method for UPLC coupled with QTOF mass spectrometer. The chemicals could then be ranked by their relative intrinsic clearance. The analyses were reproducible, with coherence of the calculated in vitro intrinsic clearance between experiments.

Cumulative dietary risk assessment of chronic acetylcholinesterase inhibition by residues of pesticides.

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.

Scientific Opinion of the Scientific Panel on Plant Protection Products and their Residues (PPR Panel) on testing and interpretation of comparative in vitro metabolism studies.

EFSA asked the Panel on Plant Protection Products and their residues to deliver a Scientific Opinion on testing and interpretation of comparative in vitro metabolism studies for both new active substances and existing ones. The main aim of comparative in vitro metabolism studies of pesticide active substances is to evaluate whether all significant metabolites formed in the human in vitro test system, as a surrogate of the in vivo situation, are also present at comparable level in animal species tested in toxicological studies and, therefore, if their potential toxicity has been appropriately covered by animal studies. The studies may also help to decide which animal model, with regard to a particular compound, is the most relevant for humans. In the experimental strategy, primary hepatocytes in suspension or culture are recommended since hepatocytes are considered the most representative in vitro system for prediction of in vivo metabolites. The experimental design of 3 × 3 × 3 (concentrations, time points, technical replicates, on pooled hepatocytes) will maximise the chance to identify unique (UHM) and disproportionate (DHM) human metabolites. When DHM and UHM are being assessed, test item-related radioactivity recovery and metabolite profile are the most important parameters. Subsequently, structural characterisation of the assigned metabolites is performed with appropriate analytical techniques. In toxicological assessment of metabolites, the uncertainty factor approach is the first alternative to testing option, followed by new approach methodologies (QSAR, read-across, in vitro methods), and only if these fail, in vivo animal toxicity studies may be performed. Knowledge of in vitro metabolites in human and animal hepatocytes would enable toxicological evaluation of all metabolites of concern, and, furthermore, add useful pieces of information for detection and evaluation of metabolites in different matrices (crops, livestock, environment), improve biomonitoring efforts via better toxicokinetic understanding, and ultimately, develop regulatory schemes employing physiologically based or physiology-mimicking in silico and/or in vitro test systems to anticipate the exposure of humans to potentially hazardous substances in plant protection products.

Peer review of the pesticide risk assessment of the active substances Pepino Mosaic Virus,EU strain, mild isolate Abp1 and Pepino Mosaic Virus,CH2 strain, mild isolate Abp2.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, Spain, for the pesticide active substances Pepino Mosaic Virus, EU strain, mild isolate Abp1 and Pepino Mosaic Virus, CH2 strain, mild isolate Abp2 and the considerations as regards the inclusion of the substances in Annex IV of Regulation (EC) No 396/2005 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 use of Pepino Mosaic Virus, EU strain, mild isolate Abp1 and Pepino Mosaic Virus, CH2 strain, mild isolate Abp2 as an elicitor on tomato (permanent greenhouse production systems). The reliable endpoints, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed.

Peer review of the pesticide risk assessment of the active substance phosmet.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Spain, and co-rapporteur Member State, Greece, for the pesticide active substance phosmet and the assessment of applications for maximum residue levels (MRLs) 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 uses of phosmet as an insecticide on citrus fruits, pome fruits, peaches/nectarines and potatoes (field uses). 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 identified.

Peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp. kurstaki strain EG2348.

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, Denmark, and co-rapporteur Member State, the Netherlands, for the pesticide active substance Bacillus thuringiensis subsp. kurstaki strain EG2348 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 uses of Bacillus thuringiensis kurstaki strain EG2348 as an insecticide on pome fruits (field use), solanaceous fruiting vegetables (uses in permanent greenhouse and walk-in tunnel) and ornamentals (field, permanent greenhouse and walk-in tunnel uses). 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 identified.

Peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp. kurstaki strain PB 54.

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Denmark, and co-rapporteur Member State, the Netherlands, for the pesticide active substance Bacillus thuringiensis subsp. kurstaki strain PB 54 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 uses of Bacillus thuringiensis subsp. kurstaki strain PB 54 as an insecticide on stone fruit and ornamentals (field uses) and tomato (field, permanent greenhouse and walk-in tunnel uses). 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 identified.

Peer review of the pesticide risk assessment of the active substance calcium carbonate.

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Spain and co-rapporteur Member State Hungary for the pesticide active substance calcium carbonate 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 uses of calcium carbonate as a repellent on deciduous and coniferous trees in forestry. 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. No concerns were identified.

Peer review of the pesticide risk assessment of the active substance Bacillus amyloliquefaciens strain IT-45.

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, France, for the pesticide active substance Bacillus amyloliquefaciens strain IT-45 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 use of Bacillus amyloliquefaciens strain IT-45 as a fungicide on citrus (field use, application to soil via drip irrigation systems). 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.

Peer review of the pesticide risk assessment of the active substance Bacillus amyloliquefaciens strain QST 713 (formerly Bacillus subtilis strain QST 713).

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Germany, and co-rapporteur Member State, Denmark, for the pesticide active substance Bacillus amyloliquefaciens strain QST 713, formerly Bacillus subtilis strain QST 713, 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 uses of Bacillus amyloliquefaciens strain QST 713 as a fungicide on strawberry (field and greenhouse uses) and grapes (field use). 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 identified.

Peer review of the pesticide risk assessment of the active substance potassium hydrogen carbonate.

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, the Netherlands and co-rapporteur Member State, Greece, for the pesticide active substance potassium hydrogen carbonate and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 uses of potassium hydrogen carbonate as a fungicide on strawberry, wine and table grapes, pome fruits, stone fruits, ornamentals and cucurbits. 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 not identified.

Peer review of the pesticide risk assessment of the active substance blood meal.

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 Austria and co-rapporteur Member State Lithuania for the pesticide active substance blood meal and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 uses of blood meal as a game repellent on deciduous and coniferous trees in forestry, orchard trees and ornamental plants and as a vole repellent on deciduous and coniferous trees in forestry (field uses). 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. No concerns are identified.

Peer review of the pesticide risk assessment of the active substance chloropicrin.

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the initial rapporteur Member State the United Kingdom and the new rapporteur Member State Italy for the pesticide active substance chloropicrin 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 chloropicrin as a soil fumigant on strawberries, tomatoes, peppers, cucurbits (field and greenhouse applications) and tree crops: pome fruit, stone fruit, citrus, olives (field applications). 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.

Peer review of the pesticide risk assessment for the active substance sulfoxaflor in light of confirmatory data submitted.

The conclusions of EFSA following the peer review of the initial risk assessment carried out by the competent authority of the co-rapporteur Member State, the Czech Republic, for the pesticide active substance sulfoxaflor are reported. The context of the peer review was that requested by the European Commission following the submission and evaluation of confirmatory ecotoxicology data. The conclusions were reached on the basis of the evaluation of the representative uses of sulfoxaflor as an insecticide on fruiting vegetables (field and greenhouse application), cucurbits (field and greenhouse application), spring and winter cereals (field application) and cotton (field application). 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. For the field and non-permanent structure greenhouses, a high risk to honeybees and bumble bees was identified related to some pertinent scenarios (treated crop scenario except after flowering period, weed scenario, field margin scenario). A low risk was concluded for honeybees, bumble bees and solitary bees in case of permanent structure greenhouse provided the low exposure in such scenarios. The European Commission mandated EFSA to complete the assessment of the spray drift reducing measures necessary to protect bumblebees and solitary bees in field margins from exposure to sulfoxaflor and to complete the assessment of the risk to bees from puddle water.

Peer review of the pesticide risk assessment of the active substance kieselgur (diatomaceous earth).

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Austria and co-rapporteur Member State Greece for the pesticide active substance kieselgur (diatomaceous earth) and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 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 uses of kieselgur (diatomaceous earth) as an insecticide and acaricide on stored cereals, empty storage rooms and storage rooms, mills and warehouses (with stored goods). 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.