Interpretation of bioassay monitoring data following exposure to natural uranium through inhalation

Bioassay monitoring is carried out for occupational workers for estimation of internal dose likely to be received by them following acute/chronic intake of radioactivity. Interpretation of individual Bioassay and/or Whole Body/Lung Monitoring data requires knowledge on the type and particle size of the aerosols when the exposure is through inhalation. However, in most of the exposure situations this information may not be available a priori and this has to be inferred from the follow-up studies carried out by various monitoring techniques. The present paper describes the internal dose computation in incidents of suspected exposure of occupational workers to U (nat.) when specific information on the physicochemical characteristics of the inhaled aerosols is not available. The paper also shows how several bioassay data sources (e.g. urine and thorax monitoring), when used together; considerably increase the reliability of internal dose assessment. (author)