Workability of the guidance documents for the categoryor read-across approach for selected groups of chemicals

摘要

The current international guidance documents for performing a group-basedassessment of the possible risks caused by chemical substances withcomparable structures need further elucidation if they are to be properlyused. This was the result of RIVM research on the workability ofguidance documents.This research was prompted by the upcoming European legislation onproduction, trade and use of chemical substances (REACH), which will comeinto force in mid-2007. This legislation stipulates that about 30,000chemical substances are to be assessed on their possible risks.Several non-animal methods such as QSARs, in vitro methods and thecategory or read-across approach have been developed to assess this largenumber of chemicals. The physico-chemical and toxicological propertiesare only known for a minority of all chemical substances. These may forexample include skin irritation, water solubility and degradation in theenvironment. The category or read-across approach uses availablesubstance information to be able to assess chemical substances withcomparable structures for which only few data are available.The current guidance document for this approach can be used as a basis,but several points still need more attention in the further developmentof the guidance document for REACH. One point of particular interest isestablishing a clear definition of the categories for use in theread-across approach to avoid comparing unequal data. Data substantiatedand clearly presented for this approach highly define the usefulness ofthis new system.