Navigating the Challenges of Endocrine Disruption Assessment in the EU

Endocrine-disrupting chemicals (EDCs) pose significant challenges for regulatory bodies, scientists, and industries, particularly in the European Union (EU). EDCs can interfere with hormonal systems, causing adverse effects on both human health and the environment. The EU has responded to these concerns by tightening regulations, especially under the Plant Protection Products Regulation (PPPR), Biocidal Products Regulation (BPR), and the REACH regulation, which governs industrial chemicals.

Since 2018, ED assessments have been mandatory for the approval of plant protection and biocidal products in the EU, applying to both active and non-active substances. The introduction of new hazard classes under the Classification, Labelling, and Packaging (CLP) regulation has further emphasized the importance of ED assessments. However, despite the existence of multiple guidelines, the process remains complex due to the intricacies of the hormonal system and the properties of certain substances, such as UVCBs (unknown or variable composition, complex reaction products, or biological materials) and polymers.

Key Challenges in ED Assessment:

1. Complexity of the Hormonal System: The hormonal system’s complex and not yet fully understood nature makes it challenging to establish clear criteria for identifying EDCs. The criteria involve demonstrating an endocrine mode of action, observing adverse effects, and proving these effects are directly linked to the endocrine mode of action.
2. Non-active Substances: Substances like safeners and synergists in plant protection products undergo evaluation similar to active substances. However, co-formulants with ED properties are considered unacceptable and are listed in Annex II of the PPPR. This process often requires extensive database screening and expert literature searches, which can be time-consuming and may still lead to inconclusive results.
3. Industrial Chemicals: While there is currently no mandatory ED assessment for industrial chemicals under REACH, substances identified as endocrine disruptors can be classified as substances of very high concern (SVHCs). The recent introduction of new ED hazard classes in the CLP regulation highlights the EU’s commitment to addressing EDCs. However, assessing the ED potential of complex substances like polymers remains an area of ongoing research and debate.
4. Non-animal Testing: The use of in vitro assays, QSAR models, and read-across approaches provides alternatives to animal testing, helping to reduce costs and ethical concerns. However, these methods may not always offer sufficient evidence, especially for complex substances like UVCBs, where the QSAR toolbox often lacks detailed information.
5. Animal Testing and Environmental Studies: In cases where non-animal testing does not provide conclusive results, animal testing may be necessary. This approach focuses on the oestrogen, androgen, thyroid, and steroidogenesis (EATS) mediated modes of action. Testing challenges include issues with water solubility, choice of test concentrations, and the development of analytical methods, particularly for environmental studies with aquatic species.

Moving Forward:
To address these challenges, experts emphasize the importance of collaboration between study directors, regulatory experts, and statisticians to design studies that are fit for regulatory purposes. As the regulatory landscape continues to evolve, developing and refining methods for ED assessment will be crucial, especially for complex substances like UVCBs and polymers. The introduction of new hazard classes for EDCs marks a significant advancement in chemical regulation, signaling the EU’s commitment to protecting human health and the environment from the potential risks of endocrine disruptors.

For a more detailed exploration of these challenges and potential solutions in endocrine disruption assessment, please refer to the full article linked below.

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