Prevention of bony fluorosis in aluminum smelter workers. A five-year study of fluoride absorption and excretion -- Pt. 3.

1. A study of over 52,000 urinary fluoride determinations collected over a 5-year period among aluminum smelter workers is described. The pre-shift urinary fluoride concentration (representative of bony burden) appears to increase less rapidly than the post-shift concentration. This slow rate of bony buildup of pre-shift urinary fluoride concentrations reflects the relatively slow uptake of fluoride by osseous tissues at these levels of exposure. 2. The utility of post-shift urinary fluoride analysis is reflected by its close correlation with improvement or deterioration in work practices which determines the degree of potential fluoride exposure. 3. Over 16,000 urinary tests for protein were performed in aluminum smelter workers. The absence of correlation between urinary fluoride concentrations and the presence of albuminuria indicates the absence of renal alteration among these workers.