Breath - a database on occupational exposure limits and local irritation

At present, occupational exposure limits (OELs) are derived from animal testing or human experiences. However, there is still a large number of chemicals without health-based OEL. The EU project OSIRIS focuses on intelligent testing strategies and prediction modules. These approaches could be used to fill gaps in OEL derivation. In this context, a database called Breath with focus on OELs and irritating effects after inhalation has been developed, as inhalation is the most important occupational exposure. Currently, the database consists of three sections: - Physicochemical part describing the intrinsic properties. - RD50-values (decrease in respiratory frequency; Alarie bioassay) describe the irritating properties. - OEL-section describes all studies (human and animal) used for OEL derivation. Breath contains over 200 substances with a German MAK value (according to the MAK statement of the DFG MAK commission) and/or RD50-value. Initially, the relationship of German MAK and RD50 value was assessed. In general there is a good correlation of the German MAK and the RD50-value for substances that are classified as local irritants by the DFG MAK commission. Only few compounds, e.g. acetone and R-(+)-limonene do not meet this correlation. A linear correlation was also obtained for German MAK values and human or animal LOELs. Furthermore, RD50-values correlate with human LOELs, however there are deviations. With regard to the substances deviating from the correlations further analysis is envisaged. Breath will further be used to derive SAR-concepts for locally irritation based on RD50-values, NOELs (animal and human) and OELs as surrogates for NOELs.