Reference n° ENV/CBC/MONO(2025)18

Date: 31.10.2025

Overview:

This OECD Guidance Document sets out best-practice approaches to improve generation, reporting, sharing and regulatory use of research data for chemical hazard and risk assessments. It defines reporting, reliability and relevance principles, and emphasises FAIR data, tailored reporting templates, and tools to bridge non-standard academic data with regulatory evidence needs.

The Guidance describes workflows for researchers and assessors: designing studies for regulatory utility, structured literature searching and screening, use of evaluation tools (e.g., SciRAP, CRED), systematic review methods, and case studies illustrating integration of research data into regulatory decisions and recommendations for harmonised practices.

Main points

- Regulatory Uptake of Research Data: Improving the use of non-standard research data in regulatory chemical assessments enhances scientific robustness and supports legal requirements to consider all available evidence.

• - Stakeholder Responsibilities: Researchers, funders, publishers, reviewers, repository managers, and risk assessors all share responsibility to increase the regulatory utility and uptake of research data throughout its lifecycle.
• - Principles of Data Quality: High-quality reporting, reliability (internal validity), and regulatory relevance (external validity) are essential for research data to be useful in regulatory contexts.
• - Reporting Standards and Templates: Adhering to established reporting standards (such as OECD Harmonised Templates, ARRIVE, STROBE, SciRAP, CRED) and using structured data repositories maximises data accessibility, transparency, and reuse.
• - Systematic Review and Evidence Integration: Structured approaches such as systematic reviews and systematic evidence maps (SEMs) are recommended for identifying, screening, evaluating, and integrating research data in regulatory assessments.
• - Fit-for-Purpose Evaluation Tools: Use of clear, context-appropriate evaluation tools and critical appraisal methods is necessary for transparent, consistent assessment of study reliability and relevance; qualitative tools are preferred over simple scoring systems.
• - Publication of All Results: Both positive and negative (no-effect) results should be published and made accessible to avoid bias, support model development, and prevent unnecessary repetition of studies, especially animal studies.
• - Recommendations for Harmonisation and Training: Adoption of harmonised reporting, evaluation tools, and ongoing training for all stakeholders is critical to improve the quality, consistency, and regulatory acceptance of research data.

Citations:

Please cite this publication as:
OECD (2025), OECD Guidance Document on the Generation, Reporting and

Use of Research Data for Regulatory Assessments, OECD Series on Testing and Assessment, No. 417, OECD Environment, Health and Safety, Paris, https://one.oecd.org/document/ENV/CBC/MONO(2025)18/en/pdf

Reference n° ENV/CBC/MONO(2025)19

Date: 30.10.2025

Overview:

This OECD guidance details a comprehensive, updated framework for grouping chemicals—via analogue and category approaches—to support hazard assessment, reduce animal testing, and inform regulatory decisions. It integrates traditional methods with New Approach Methodologies (NAMs), (Q)SARs, omics, AOPs, and IATA/Defined Approaches to improve read-across, trend analysis, and uncertainty characterization.

The third edition provides stepwise workflows, reporting templates, tools, and case studies for selecting analogues, forming categories, and documenting read-across justifications across diverse substance types (including UVCBs, metals, nanomaterials), emphasizing applicability domains, data quality, and iterative review.

Main points:

Chemical Grouping Approaches : Grouping chemicals enables hazard assessment by considering structurally or mechanistically similar chemicals together, using either analogue (one-to-one or few-to-few) or category (many-to-many) approaches to fill data gaps and reduce animal testing.

Read-Across and Data Gap Filling : Read-across uses data from one or more source chemicals to predict properties or hazards of a target chemical lacking data, and can be qualitative (binary) or quantitative (numerical value); it is central to both analogue and category approaches.

Category Formation and Trends : Categories are defined by common structural, physicochemical, or mechanistic features, and allow for the identification of trends (e.g., toxicity, potency) across members, which supports interpolation and extrapolation to fill data gaps.

Uncertainty Assessment : Evaluation of uncertainties is essential in grouping and read-across, considering data quality, similarity rationale (structural, physicochemical, metabolic, bioactivity, MOA), and robustness of predictions; multiple frameworks and templates exist for systematic uncertainty assessment.

Role of New Approach Methodologies (NAMs) : NAMs, including in vitro assays, omics (transcriptomics, metabolomics), high-throughput/content screening (HTS/HCS), and computational models ((Q)SARs), provide supporting evidence for similarity, mechanistic justification, and can increase confidence in grouping.

Applicability Domain and Boundaries : Clearly defining the applicability domain—structural, physicochemical, and mechanistic boundaries—determines which chemicals can be reliably included in a group or category and supports regulatory acceptance.

Reporting and Documentation : Transparent documentation is required, including the rationale, data matrices, justification for inclusion/ exclusion, uncertainty analysis, and reporting formats for analogue and category approaches, often using modular templates and data matrices.

Special Considerations for Complex Substances and Nanomaterials : Grouping and read-across principles apply to substances of unknown or variable composition (UVCBs), metals, inorganics, and nanomaterials, but require additional attention to compositional, physicochemical, and transformation characteristics due to their complexity and variability.

Summary

Introduction

This document provides comprehensive guidance on the grouping of chemicals for hazard assessment, offering methodologies to increase efficiency, reduce animal testing, and ensure scientific robustness in regulatory and scientific contexts.

Key Insights and Themes

• Grouping Approaches enable the assessment of chemicals as analogues or categories, allowing data from tested chemicals to predict properties of untested ones, thus reducing the need for extensive testing.

• Analogue Approach uses empirical data from one or more structurally or mechanistically similar chemicals to predict properties for a specific target chemi- cal, emphasizing the importance of shared mode or mechanism of action.

• Category Approach organizes chemicals into groups with similar or regularly patterned properties, supporting hazard assessment through trend analysis and read-across within the group.

• Read-Across and Data Gap Filling are central techniques, where information from one chemical or group is used to fill data gaps for others, and can be applied qualitatively or quantitatively.

• Uncertainty Analysis is integral, requiring systematic identification, characteri- zation, and documentation of uncertainties in both data and similarity rationales to ensure robust predictions.

• New Approach Methodologies (NAMs), such as in vitro assays, omics tech- nologies, high-throughput screening, and computational models, are increasingly used to substantiate similarity and support grouping hypotheses.

• Bioactivity Similarity leverages biological response data (e.g., from omics or HTS/HCS) as evidence for grouping, with confidence strengthened by mechanistic links to endpoints or adverse outcome pathways.

• Adverse Outcome Pathways (AOPs) provide mechanistic frameworks linking molecular events to adverse effects, supporting grouping and read-across by clari- fying the biological plausibility of groupings.

• Integrated Approaches to Testing and Assessment (IATA) and Defined Ap- proaches (DA) combine multiple evidence sources, including grouping, to guide hazard and risk assessment in a structured manner.

• Applicability Domains and Boundaries must be clearly defined for both ana- logues and categories, specifying structural, physicochemical, and mechanistic cri- teria for group membership and reliable predictions.

• Subcategories and Breakpoints may arise within categories when trends do not apply uniformly, requiring endpoint-specific justifications and potentially lead- ing to subcategorization for regulatory clarity.

• Regulatory Context and Evolution drive the development of grouping guid- ance, with frameworks like EU REACH and ECHA’s Read-Across Assessment Frame- work (RAAF) shaping scientific and documentation standards.

• Reporting Formats for analogue and category approaches are standardized to ensure transparency, reproducibility, and comprehensive justification, including data matrices and explicit uncertainty assessments.

• Computational Tools such as the OECD QSAR Toolbox, GenRA, and others support analogue identification, trend analysis, and category development by pro- viding systematic and reproducible methods.

• Special Considerations are addressed for complex substances (UVCBs), met- als, inorganic compounds, and nanomaterials, with tailored grouping and read- across strategies reflecting their unique characteristics and data challenges.

• Weight of Evidence (WoE) Approaches are recommended to integrate multi- ple lines of evidence, address data gaps, and support regulatory decision-making with transparent confidence assessments.

• Continuous Evolution of the guidance is expected, reflecting advances in sci- ence, technology, and regulatory experience, with periodic updates to incorporate new data sources, methodologies, and case studies.

• International Collaboration underpins the development and harmonization of grouping approaches, with contributions from global regulatory agencies, scientif- ic experts, and industry stakeholders.

Conclusion

Grouping of chemicals, supported by robust methodologies, uncertainty analysis, and evolving scientific tools, enables more efficient, ethical, and scientifically sound hazard assessment for regulatory and research purposes.

Citation: not available

Reference n°: ENV/CBC/MONO(2025)17

Date: 24.10.2025

Overview:

The document presents OECD findings from the ninth review cycle (2023) of Integrated Approaches for Testing and Assessment (IATA) case studies, summarising lessons from three submissions on agrochemical carcinogenicity read-across, surfactant eye-irritation defined approaches, and bioaccumulation IATAs. It explains project aims, templates, review processes, and the scope of OECD guidance linking New Approach Methods (NAMs), AOPs, and weight-of-evidence (WoE) applications.

Key takeaways include methodological strengths and uncertainties for analogue selection by mode of action, the Defined Approach for Surfactants (DASF) performance and limits, and approaches to scoring and integrating evidence for bioaccumulation. The report identifies priority topics for further guidance, such as uncertainty analysis, applicability domains, PBK/IVIVE, and confidence-building with limited reference chemicals.

Summary

This document reviews the ninth cycle (2023) of OECD case studies on Integrated Approaches for Testing and Assessment (IATA) for chemical safety, highlighting new methodologies, lessons learned, and future guidance needs.

Key Insights and Themes

Global Expansion of NAMs reflects the increased use of New Approach Methods (NAMs) for chemical safety assessment, driven by the need to reduce animal testing and leverage advances in biotechnology.

OECD Guidance Development includes creation of documents and tools supporting NAMs, such as in silico, in chemico, in vitro, and in vivo methods, and guidance for Adverse Outcome Pathways (AOPs).

IATA Case Study Project (CSP) was launched to facilitate sharing and review of real-world applications of IATAs and promote regulatory acceptance.

Annual Review Cycle involves expert review and discussion of submit- ted case studies, focusing on strengths, uncertainties, and regulatory relevance, with findings published for transparency.

Ninth Review Cycle (2023) examined three case studies: chronic toxicity and carcinogenicity of agrochemicals, eye hazard identification of surfactants, and bioaccumulation assessment.

Analogue Selection for Read-Across in carcinogenicity assessment prioritizes mode of action (MoA) or biological response over structural similarity, with detailed justification and uncertainty analysis required.

Defined Approach for Surfactants (DASF) was developed for eye irritation testing, demonstrating high predictive accuracy across surfactant classes but limited by the small number of Cat. 2 reference chemicals.

Weight of Evidence (WoE) Scoring is context-dependent; transparent, fit-for-purpose scoring and weighting of lines of evidence are essential for integrating diverse data in bioaccumulation assessments.

Uncertainty Assessment is a recurring challenge, with frameworks and templates provided to systematically document and communicate uncertainty in read-across and WoE approaches.

Regulatory Applicability varies by country and sector; while many approaches are promising, barriers include data availability, validation of new methods, and regulatory requirements for specific endpoints.

IATA Framework Template was introduced to standardize and facilitate the reuse of IATA case studies, with ongoing improvements planned for endpoint-specific applications.

Guidance Priorities Identified include increasing confidence in IATA/ DA performance with limited reference chemicals, integrating multiple data streams, defining applicability domains, and improving uncertainty analysis.

Limitations and Needs highlight the need for further validation, broader chemical coverage, improved reporting, and harmonization of approaches for complex endpoints like carcinogenicity and bioaccumulation.

Examples and Templates for reporting, data matrices, and uncertainty assessment are provided to enhance reproducibility and clarity in future case studies.

Stakeholder Engagement in the review process ensures diverse regulatory perspectives and identifies practical challenges in applying IATAs to real-world assessments.

Continuous Improvement is driven by lessons learned from each review cycle, with feedback informing updates to templates, guidance documents, and regulatory practices.

Transparency and Documentation are emphasized throughout, with detailed templates and reporting formats to support regulatory acceptance and scientific rigor.

International Harmonization is an overarching goal, with the OECD facilitating the development of common frameworks and guidance to support global regulatory use of IATAs and NAMs.

Conclusion

The ninth review cycle advances the development and regulatory application of IATAs and NAMs, identifying key challenges and priorities for future guidance to support global chemical safety assessment.

Citation:

OECD (2025), REPORT ON CONSIDERATIONS FROM CASE STUDIES ON INTEGRATED APPROACHES FOR TESTING AND ASSESSMENT (IATA) Ninth Review Cycle (2023), OECD Series on Testing and Assessment, No 416, OECD Environment, Health and Safety, Paris, https://one.oecd.org/official-document/ENV/CBC/ MONO(2025)17/en

Reference n° ENV/CBC/MONO(2025)16

Date: 14.10.2025

Overview:

The OECD monograph presents Integrated Approaches for Testing and Assessment (IATA) using combined bioinformatics tools to extrapolate chemical toxicity across species. It details the complementary use of SeqAPASS and G2P-SCAN to evaluate protein and pathway conservation, supporting hazard identification, prioritization, and regulatory decision-making while reducing animal testing.

The document describes workflows, case studies (PPARα, ESR1, GABRA1), tool inputs/outputs, uncertainties, and regulatory applications (ERA, endocrine disruption, endangered species). It provides method guidance, software instructions, and evidence synthesis strategies for implementing NAMs in cross-species chemical safety assessments.

Main points:

Bioinformatics Integration: Combining the SeqAPASS and G2P-SCAN computational tools enables robust cross-species extrapolation of chemical toxicity by assessing both protein target and biological pathway conservation, supporting more informed chemical safety assessments while reducing animal testing.

Key Tools: SeqAPASS predicts species susceptibility to chemicals by evaluating protein sequence and structural conservation across thousands of species, while G2P-SCAN analyzes the conservation of biological pathways using human gene inputs and model organisms.

Regulatory Relevance: These approaches align with global regulatory trends favoring New Approach Methodologies (NAMs), facilitating mechanistic, transparent, and ethical chemical risk assessments that minimize reliance on animal testing.

Workflow Process: The integrated workflow involves identifying a chemical’s molecular target, mapping its associated biological pathways, prioritizing key pathway proteins, and using both tools to predict conservation and susceptibility across species, which informs regulatory decision-making.

Expert Judgment Requirement: Critical steps such as target identification, isoform selection, and pathway prioritization rely on expert judgment, often requiring literature review, evaluation of empirical evidence, and knowledge of protein structure-function relationships.

Limitations: The approach is limited by the availability and quality of protein and gene sequence data, incomplete pathway annotation in non-model species, and is most applicable when the chemical’s molecular target is known and well characterized.

Regulatory Applications: Results are used for hazard identification, prioritization, and as additional lines of evidence in weight-of-evidence evaluations for regulatory frameworks such as the Endangered Species Act, endocrine disruptor screening, and pesticide registration.

Case Study Outcomes: Application to chemicals like 2-ethylhexanoic acid, diethylstilbestrol, and topiramate demonstrated that consensus between SeqAPASS and G2P-SCAN enhances confidence in predicting pathway conservation and chemical susceptibility across mammalian and other vertebrate species.

Summary

Introduction

This document presents integrated bioinformatics approaches for extrapolating chemical toxicity knowledge across species to inform chemical safety assessments, aiming to reduce reliance on animal testing and improve regulatory decision-making.

Key Insights and Themes

• Global regulatory shift increasingly favors New Approach Methodologies (NAMs), such as computational and cell-based tools, to assess chemical safety in an ethical, efficient, and scientifically robust manner.

• Cross-species extrapolation is essential for chemical risk assessment, enabling predictions about chemical effects in untested or protected species based on data from surrogate organisms.

• Traditional methods like safety factors and species sensitivity distributions have limitations due to assumptions about interspecies relatedness and data availability.

• Bioinformatics tools—notably SeqAPASS (Sequence Alignment to Predict Across Species Susceptibility) and G2P-SCAN (Genes-to-Pathways Species Conser- vation Analysis)—enable systematic evaluation of protein and pathway conservation across species.

• SeqAPASS assesses protein sequence and structural conservation to predict potential chemical-protein interactions across thousands of species, supporting chemical susceptibility predictions.

• G2P-SCAN analyzes conservation of biological pathways using human gene inputs, mapping orthologs and functional families across key model species to infer pathway conservation.

• Combined application of SeqAPASS and G2P-SCAN strengthens the weight of evidence by integrating molecular (protein) and pathway-level data, enhancing confidence in species extrapolation.

• Integrated approach supports hazard assessment, prioritization in early screening, and intelligent test design by identifying the most biologically relevant species for further testing.

• Regulatory context is evolving to accept mechanistic, cell-based, and computational data, requiring transparent, scientifically robust methods for cross-species extrapolation.

• Applicability domain for these approaches requires a known chemical-biomolecule interaction in at least one species and relies on high-quality sequence and annotation data.

• Workflow involves identifying chemical targets, mapping pathways, prioritizing key proteins, and combining evidence from both tools to generate lists of susceptible species.

• Expert judgment is critical at multiple decision points, including target selection, isoform choice, and interpretation of orthology and pathway conservation results.

• Uncertainties arise from incomplete knowledge of chemical-protein interactions, taxonomic coverage, and lack of empirical evidence for some pathways or species, but can be reduced by integrating multiple data sources.

• Case studies demonstrate the approach using chemicals such as 2-ethylhexanoic acid (PPARα target), diethylstilbestrol and butylparaben (ESR1 target), and topiramate (GABRA1 target), showing practical application and limitations.

• Results from combined approaches provide lists of species likely to be susceptible based on pathway and protein conservation, supporting regulatory decisions for hazard identification, prioritization, and species protection.

• Links to Adverse Outcome Pathways (AOPs) allow mapping of molecular and functional data to regulatory-relevant outcomes, helping to define the biologically plausible taxonomic domain of applicability (tDOA) for AOPs.

• Regulatory applications include support for the Endangered Species Act, endocrine disruptor screening, and pesticide registration, by identifying at-risk species and guiding intelligent testing strategies.

• Open-source and accessibility of tools like SeqAPASS and G2P-SCAN, along with transparent workflows, facilitate broader adoption and continuous improvement as more sequence data become available.

Conclusion

Integrating computational bioinformatics tools like SeqAPASS and G2P-SCAN enables more transparent, scientifically robust, and ethically responsible cross-species extrapolation for chemical safety assessment, supporting regulatory decisions and reducing reliance on animal testing.

Citation:

OECD (2025), Case Studies for the Integrated Approaches for Testing and Assessment in the Application of Combined Bioinformatics Approaches for Cross Species Extrapolation of Toxicity Knowledge to inform Chemical Safety. Tenth Review Cycle (2024), OECD Series on Testing and Assessment, No 415, OECD Environment, Health and Safety, Paris, https://one.oecd.org/official-document/ENV/CBC/ MONO(2025)16/en

Reference n°doi: 10.2903/j.efsa.2023.8194

Date: 14.07.2023

Overview:

This guidance establishes a tiered framework for assessing how drinking-water treatment processes transform residues of active substances (from plant protection and biocidal products) and their environmental metabolites, determining whether harmful treatment transformation products (tTPs) may form in surface water, groundwater or bank filtrate used for drinking‑water production. It prescribes exposure screening, PEC calculations, dilution factors per EU regulatory zone, and criteria to identify substances that trigger further tTP assessment.

It then details laboratory and in‑silico approaches to predict and confirm tTP formation across common processes (chlorination, chloramination, ClO2, ozonation, UV, advanced oxidation, sand/GAC filtration), and provides a three‑tiered human and domesticated‑animal hazard and risk assessment pathway emphasizing genotoxicity screening, avoidance of unnecessary vertebrate testing, and use of weight‑of‑evidence and alternative methods.

Summary of key points impacting PPPs

The guidance document introduces several critical requirements and procedures that directly impact the approval and authorisation of PPPs, particularly regarding their residues and transformation products in drinking water:

Tiered Risk Assessment Framework

A tiered framework is established to assess the risk of PPP active substances (AS) and their environmental transformation products (eTPs) in water abstracted for drinking water production. This aims to identify whether harmful treatment transformation products (tTPs) may form during water treatment and how to assess their impact on human and animal health (pages 1, 3 and 9).

The framework is designed to avoid unnecessary testing, especially vertebrate testing, and to use weight-of-evidence and alternative methods whenever possible (pages 3 and 10).

Exposure Assessment and Trigger Values

The guidance requires calculation of Predicted Environmental Concentrations (PECs) for AS and eTPs in both surface water and groundwater that may be used for drinking water (p.3 and 11).

Dilution factors are applied to surface water PECs to estimate concentrations at drinking water abstraction points. These factors differ by European regulatory zone (Central: 2, South: 5, North: 10) and are further refined by land-use type (pages 4, 18 and 86).

Substances with PECs above 0.1 μg/L at the abstraction point must be assessed for their potential to form tTPs during water treatment (p. 3, 14 and 29).

Identification and Assessment of Transformation Products

Both the parent AS and their main eTPs must be considered for literature review, modelling, and experimental testing to determine if tTPs are formed during drinking water treatment (p. 33, 34).

Experimental approaches involve first testing at high concentrations to detect possible tTPs, then repeating at environmentally relevant concentrations. Only tTPs detected above 0.075 μg/L in the final water require full identification and risk assessment (p. 33, 34, 35).

Common treatment processes considered include rapid sand filtration, chlorination, chloramination, chlorine dioxide, ozonation, and UV disinfection (p. 32, 36).

Hazard and Risk Assessment of tTPs

A three-tiered risk assessment is applied to tTPs:

Tier 1: Genotoxicity screening (using QSARs, read-across, or experimental data). Non-identified tTPs above 0.075 μg/L are considered genotoxic unless proven otherwise (p.44).

Tier 2: General toxicity assessment, comparing aggregate exposure to health-based guidance values (HBGVs) or Thresholds of Toxicological Concern (TTC) (p.48).

Tier 3: Further targeted testing if specific hazards (e.g., neurotoxicity, endocrine disruption) are suspected (p.50).

If a tTP does not pass the hazard or risk assessment, its presence at relevant concentrations is unacceptable and may preclude PPP approval or trigger mitigation (p. 44, 49, 50).

Data Requirements and Modelling Tools

Applicants must use agreed EU models (e.g., FOCUS Surface Water and Groundwater Scenarios, TOXSWA, PEARL, PELMO, PRZM) for PEC calculations (p. 13, 16, 20).

Substance-specific data, including degradation rates, sorption coefficients, and transformation pathways, must be provided (p. 13, 16).

Existing data from environmental fate and metabolism studies should be utilised before conducting new tests (p. 23).

Mitigation and National Considerations

If risks are identified, mitigation measures (e.g., buffer zones, application restrictions) must be considered and implemented in the risk assessment (p. 17, 49).

Note that national authorities may require additional scenario assessments.

Reference n°247

Date: 9.10.2017

Overview:

This OECD test guideline specifies a laboratory method to determine acute oral toxicity (LD50, NOED) of pesticides and chemicals to adult worker bumblebees (Bombus spp.) using single-housed workers fed treated 50% sucrose solution. It covers test design, dosing, controls, analytical verification, observation times up to 96 hours, validity criteria, and data reporting requirements for regulatory risk assessment.

The protocol details colony selection, acclimatisation, feeding procedures, housing, environmental conditions, non-feeder handling, limit and dose-response tests, use of reference substances, and required study-report content including raw data, measured concentrations, statistical analyses, and documentation of deviations

Main points

Purpose: Assesses acute oral toxicity of chemicals (e.g., pesticides) to adult worker bumblebees using laboratory tests to determine LD50 and evaluate potential pollinator risk.

Test Species: Uses adult worker bumblebees, primarily Bombus terrestris and Bombus impatiens, collected from medium-sized colonies with active brood and a laying queen; excludes drones, queens, and very small or large individuals.

Exposure Method: Individual bumblebees are housed singly and fed 50% (w/v) sucrose solution containing the test chemical; exposure lasts up to 4 hours, followed by ad libitum feeding with untreated sucrose solution.

Controls and Reference: Includes water and, if needed, solvent controls, plus a toxic reference substance (e.g., dimethoate) to confirm test system sensitivity.

Replication and Randomization: Requires at least 30 replicates per treatment (50 for limit tests), with bumblebees randomized across treatments and sourced from at least three different colonies to avoid colony effects.

Validity Criteria: Test is valid if control mortality is ≤10% and reference substance mortality is ≥50% at the end of the test.

Data Recording: Mortality and sublethal effects are recorded at 4–5 h, 24 h, and 48 h (extended to 72/96 h if needed); non-feeders (consuming <80% of aver- age) are excluded from endpoint calculations.

Key Endpoints: LD50 (median lethal dose) and NOED (no observed effect dose) are calculated based on actual chemical intake per bumblebee, using statistical models and corrections for control mortality.

Summary

Introduction

This document outlines the OECD Guideline 247 for conducting laboratory tests to assess the acute oral toxicity of chemicals, particularly pesticides, on adult worker bumblebees.

Key Insights and Themes

- Test Purpose is to determine the acute oral toxicity (LD50) of chemicals to adult worker bumblebees, supporting pollinator risk assessments and regulatory requirements.

- Test Species primarily include Bombus terrestris and Bombus impatiens, though the method may be applicable to other bumblebee species.

- Exposure Routes considered are oral ingestion of contaminated food, simulating real-world chemical exposure for pollinators.

- Test Design involves exposing individually housed adult worker bumblebees to a single dose of a test chemical via a 50% sucrose solution for up to 4 hours, followed by observation for at least 48 hours (up to 96 hours if needed).

- Control Groups include water control, solvent control (if applicable), and a toxic reference substance (e.g., dimethoate) to verify test sensitivity and reliability.

- Colony Source requires bumblebee workers collected from mediumsized colonies with brood and a laying queen, excluding very small, large, newly emerged, male, or queen bees.

- Randomization and Weighing ensures unbiased allocation of bumblebees to treatment groups and accurate dose calculations.

- Acclimatization of bumblebees for at least 8 hours in single housing with untreated sucrose solution is mandatory to discard unhealthy individuals before testing.

- Starvation Period of 2–4 hours before dosing ensures full consumption of the treated diet within a maximum of 4 hours.

- Dose Preparation involves dissolving the test chemical in sucrose solution, using water or an organic solvent as appropriate, and preparing appropriate control solutions.

- Analytical Verification of test solution concentrations is required at least once for the lowest and highest doses, and for new chemical batches.

- Replicates and Dosing typically require five doses in a geometric series with at least 30 bumblebees per dose group, and at least three colonies to avoid colony effects.

- Non-feeders (bumblebees consuming <80% of mean food intake) are excluded from endpoint calculations to ensure accurate toxicity values.

- Test Conditions include constant darkness, 25 ± 2 °C temperature, and 60 ± 20% relative humidity, with continuous monitoring.

- Observations include daily mortality and sublethal effects, with specific behavioral criteria for affected and moribund bees.

- Limit Test may be conducted for low-toxicity chemicals using 50 replicates per group and a high dose, proceeding to full dose-response if significant mortality occurs.

- Data Analysis requires statistical methods (e.g., Probit analysis) to determine LD50 with 95% confidence limits, correction for control mortality, and reporting of NOED if possible.

- Reporting Requirements specify detailed documentation of test chemicals, bumblebee sources, conditions, methods, raw data, and deviations from guidelines.

Conclusion

The guideline establishes a standardized, robust procedure for assessing the acute oral toxicity of chemicals to bumblebees, supporting pollinator risk assessment and regulatory decisions

27 January 2026

When it comes to crop protection, Brazil and the European Union are often compared as global agricultural heavyweights. Yet in 2025, their portfolios of active substances tell a story shaped less by ideology and more by climate, farming systems, and regulatory philosophy. On the surface, both regions rely on herbicides, fungicides, and insecticides. Dig deeper, and the comparison quickly becomes less straightforward (source).

In the European Union, around 420 active substances are approved under Regulation (EC) No. 1107/2009. (EU pesticides database). Approval is based on strict hazard- and risk-based criteria, with strong emphasis on human health, environmental protection, and sustainability. The EU’s Farm to Fork Strategy and Green Deal reinforce this approach by explicitly aiming to reduce reliance on synthetic pesticides and promote integrated pest management, low-risk products, and biological alternatives. As a result, the EU maintains a relatively curated and tightly controlled list of substances.

Brazil presents a very different picture. In 2025 alone, the country recorded more than 900 pesticide product registrations, alongside a record number of bio-input approvals (www.global-agriculture.com). While registrations are not the same as unique active substances, the scale reflects a broader and more flexible crop protection toolbox. Brazil’s regulatory framework prioritises availability and effectiveness, responding to intense pest pressure driven by tropical climates, large-scale monocultures, and double-cropping systems, such as reflected in recent legislative changes, particularly Law 14.785/2023. Soybeans, sugarcane, maize, and coffee dominate production (www.grokipedia.com), and these crops demand robust, often broad-spectrum solutions to protect yields.

These differences are especially visible in how substances are used. In the EU, several neonicotinoid insecticides have been banned or severely restricted since 2018 due to risks to pollinators, with only narrow exemptions allowed in specific cases [(https://food.ec.europa.eu/plants/pesticides/approval-active-substances-safeners-and-synergists/renewal-approval/neonicotinoids\_en]). European farmers are increasingly encouraged to adopt biological control agents such as _Bacillus thuringiensis_ or _Beauveria bassiana_, as well as pheromones and other non-chemical tools. In Brazil, while biologicals are growing rapidly, conventional chemistry remains central, and new active ingredients continue to be approved to address resistance and emerging pest challenges (source).

Farming structure plays a decisive role in this divergence. Brazil’s agriculture is dominated by vast, mechanised monocultures operating under high disease and insect pressure year-round (www.wikipedia.com). In this context, chemical crop protection is often essential to maintain productivity and economic viability (source 1) , (source 2). Europe, by contrast, operates largely under temperate conditions, with smaller farms, greater crop rotation, and a strong focus on quality and value-added markets such as wine grapes, fruit, and vegetables. These systems generally allow for more targeted and preventive pest management strategies.

For these reasons, direct comparisons between Brazil and the EU can be misleading. Pest pressure, climate, farm size, regulatory goals, and market priorities differ fundamentally. Brazil focuses on yield maximisation and global commodity supply, while the EU increasingly prioritises sustainability, environmental protection, and food system resilience. The overlap in active substances exists, but the context in which they are approved and used could hardly be more different.

In the end, comparing crop protection in Brazil and the EU is less about counting active substances and more about understanding the systems behind them. Both regions protect crops, but they do so under vastly different conditions. In that sense, the comparison really is apples and pears: similar on the surface, shaped by entirely different environments underneath.