Comparison of the guidance documents in support of EUrisk assessments with those for the derivation of EU water quality standards

摘要

Risks of both new and existing substances and of biocides in Europe arebeing evaluated using the Technical Guidance Document (TGD). TheEuropean Water Framework Directive refers to this document forestablishing Environmental Quality Standards (EQSs) for water. Anotherguidance document for the derivation of EQSs was developed on the basisof the TGD by the Fraunhofer Institt (FHI) on request of the EuropeanCommission. Our study, as documented in this report, aimed to elucidatedifferences between the two guidance documents. Besides describing themain differences in background, aim and methodology, we also considereddiscrepancies at a more technical level. Risk assessment described inthe TGD encompasses effect assessment, exposure assessment and riskcharacterisation. Determination of EQSs in the FHI document was found tooverlap with the environmental effect assessment of the TGD. Differenceswere partly technical; however, for certain substances the Fraunhofermethod could lead to lower values of EQS for water compared to thederivation of safe water concentrations (PNECs) according to the TGD. Only one PNEC for water is derived following the TGD, whereas accordingto the FHI document, several EQSs for water are calculated from toxicitydata for predators and human consumption of aquatic products. Additionally, risk assessment described in the TGD takes into accountmultiple exposure routes, while the FHI document only encompassesexposure via water. Therefore, it is theoretically possibly thatadopting PNECs as EQSs for the water compartment will not fully protecthuman health in the case of substantial exposure via air orfood.