EVALUATION OF THE PROTECTIVITY OF ASSESSMENT FACTORS IN THE REACH REGULATION

Abstract

Under REACH, a chemical risk assessmentis often conducted tduring the registration if an industrial chemical. In that chemical risk assessment, assessment factors can be used to extrapolate the toxicity of a chemical with a low amount of testing. These assessment factors are responsible to account for four kinds of uncertainty. These uncertainties are laboratory variation, biological variation, acute to chronic extrapolation and lab to field extrapolation. In this thesis, these uncertainties were evaluated based on how they present in databases from ECHA, EFSA and the US EPA. All tests with environmentally relevant effects, commonly used test durations and with algae, crustaceans, fish and molluscs were included in the evaluation. Additionally, the toxicity of industrial chemicals was compared to the toxicity of pharmaceuticals and pesticides. Finally, the tiered system as proposed by the guidance document of ECHA for REACH is evaluated on its ability to account for those uncertainties in the first four tiers. The analysis shows that the biggest uncertainty was the biological variation between species. The median variation between the most sensitive and least sensitive organisms of the same species group was 100. The median acute to chronic ratio was determined as 3.5 for algae and 11 for crustaceans, fish and molluscs. The laboratory variation showed a median variation of 2.2 and the lab to field extrapolation showed a median variation of 1. The median toxicity of Industrial chemicals was lower than that of pesticides and pharmaceuticals. Industrial chemicals, which were also pesticides or pharmaceuticals, show a higher toxicity than chemicals only classified as industrial chemicals. Evaluating the tiered approach with the available data, the first four tiers are more protective than the species sensitivity distribution approach in 22% of the cases.