Guidance document on the impact of water treatment processes on residues of active substances or their metabolites in water abstracted for the production of drinking water.

This guidance document provides a tiered framework for risk assessors and facilitates risk managers in making decisions concerning the approval of active substances (AS) that are chemicals in plant protection products (PPPs) and biocidal products, and authorisation of the products. Based on the approaches presented in this document, a conclusion can be drawn on the impact of water treatment processes on residues of the AS or its metabolites in surface water and/or groundwater abstracted for the production of drinking water, i.e. the formation of transformation products (TPs). This guidance enables the identification of actual public health concerns from exposure to harmful compounds generated during the processing of water for the production of drinking water, and it focuses on water treatment methods commonly used in the European Union (EU). The tiered framework determines whether residues from PPP use or residues from biocidal product use can be present in water at water abstraction locations. Approaches, including experimental methods, are described that can be used to assess whether harmful TPs may form during water treatment and, if so, how to assess the impact of exposure to these water treatment TPs (tTPs) and other residues including environmental TPs (eTPs) on human and domesticated animal health through the consumption of TPs via drinking water. The types of studies or information that would be required are described while avoiding vertebrate testing as much as possible. The framework integrates the use of weight-of-evidence and, when possible alternative (new approach) methods to avoid as far as possible the need for additional testing.

Scientific Opinion on the setting of health-based reference values for metabolites of the active substance terbuthylazine.

The EFSA Panel on Plant Protection Products and their Residues was requested to establish health-based reference values for groundwater metabolites (LM2, LM3, LM4, LM5 and LM6) of the active substance terbuthylazine based on the available evidence, unless the evidence was considered insufficient to do so. The request was accepted under the explicit circumstance that the reassessment would be made according to a different methodology than the routine methodology currently applied for the assessment of metabolites in groundwater. While for metabolites LM2, LM4 and LM5, it was concluded that the reference values for terbuthylazine are applicable, substance-specific reference values could not be derived for metabolites LM3 and LM6. The applied threshold of toxicological concern (TTC) approach has shown that metabolites LM3 and LM6 are of potential concern for consumer health, since at least one representative groundwater leaching scenario results in exposure above the relevant threshold. Moreover, other sources of exposure to LM3 and LM6 could not be excluded with certainty. It is therefore recommended to address the specific toxicities of metabolites LM3 and LM6.

Guidance of EFSA on risk assessments for active substances of plant protection products that have stereoisomers as components or impurities and for transformation products of active substances that may have stereoisomers.

In response to the request of the European Commission to EFSA, this document provides guidance on the information necessary to perform the risk assessment of plant protection active substances that contain stereoisomers in their composition as active components or impurities. The guidance should also be used for active substances that without containing any stereogenic element may generate transformation products or metabolites that do contain them. As a general principle, stereoisomers need to be treated as different chemical components for the risk assessment. Current data requirements in the EU regulatory framework (Regulation (EC) No 1107/2009 and Regulation (EC) No 396/2005) already establish that the substance tested should match the technical specifications (including its isomeric composition) and that formation and effects of metabolites, degradation and transformation products should be investigated (which certainly includes the case when transformation products are stereoisomers). Experience gained during the application of EU pesticides regulation has shown that guidance may be needed to provide applicants and evaluators advice on how to generate and assess the required data. Also, guidance is needed on how to make the best use of the available information to perform the risk assessment of these substances, particularly in situations when the information on individual isomers is not available or difficult to obtain, with a primary objective being to reduce the need for repeating vertebrate animal testing. This guidance does not aim to provide specific technical advice on analytical methods. In this guidance, the Regulation (EU) 283/2013 on the data requirements for the plant protection active substances is analysed and recommendations are given on how to best address and assess data requirements for active substances containing stereoisomers.