RESPIRATORY EFFECTS IN MICE EXPOSED TO AIRBORNE EMISSIONS FROM STACHYBOTRYS CHARTARUM AND IMPLICATIONS FOR RISK ASSESSMENT

Stachybotrys chartarum, a mycotoxin producing mould found in some damp buildings, was grown in aluminum dishes in closed exposure chambers. The loading factor, 5.12 m(2)/m(3), corresponded to 2.8 times the load ing in a normal room with all surfaces covered by mould. Sensory irrit ation, bronchoconstriction and pulmonary irritation effects were inves tigated using a sensitive mouse bioassay in which the airway reactions were measured plethysmographically. Little effect was seen from the v apours in agreement with the predicted effects of the low concentratio ns of volatile organic compounds measured. Even under the influence of an airflow about four times that measured in normal buildings, the co ncentration of liberated spores and other particles was very low, corr esponding to the biological effects observed, and probably reflecting the high water content of the substrate. These results demonstrate tha t many factors are important for the transport of biologically active mould metabolites from building material to occupants and that no dire ct relationship may exist between immediate biological effects and sur face area covered with mould. Therefore, risk assessments should be ba sed on estimated effects of emitted vapours, effects of liberated part icles, e.g. sensitization potentials of the mould spores and effects o f the generated metabolites (mycotoxins).