LUNG RETENTION OF CERIUM IN HUMANS

A retrospective study was conducted to evaluate lung retention of part icles containing cerium in subjects with and without previous occupati onal exposure to mineral dusts. Analytical transmission electron micro scopy was performed on 459 samples of bronchoalveolar lavage (BAL) flu id and 75 samples of lung tissue. Study of the distribution of mineral ogical species in human samples showed that particles containing ceriu m were encountered in less than 10% of subjects. The proportion of sub jects with particles containing cerium in their biological samples was not different between controls and subjects with previous occupationa l exposure to fibrous or nonfibrous mineral dusts. This was considered as the background level of lung retention of cerium in the general po pulation. By contrast, determination of the absolute concentration of particles containing cerium in BAL fluid and lung tissue samples showe d that 1.2% (from BAL fluid) and 1.5% (from lung tissue) of subjects w ith previous exposure to mineral particles had high lung retention of particles containing cerium. This study is believed to be the first on e in which lung retention of cerium was estimated in the general popul ation.