Concentration and daily excretion of uranium in urine of Japanese

Tolmachev, S.*; Kuwabara, Jun ; Noguchi, Hiroshi

Study was undertaken to investigate uranium concentrations in urine samples for nonexposed Japanese individuals and to evaluate uranium daily excretion. Uranium concentrations were measured with inductively coupled plasma mass spectrometry after microwave-assisted digestion and online separation using the UTEVA extraction chromatographic resin. The concentrations ranged from 0.8 to 35.6 ng of uranium per liter of urine (median 4.5 ng L-1). Urinary uranium was normalized relative to the creatinine concentration in order to compensate a degree of urine dilution. Creatinine-normalized values ranged from 1.2 to 17.8 ng of uranium per gram of creatinine (median 7.4 ng g-1 creatinine). These results correspond to the lower end of urinary uranium reported for nonexposed populations. Using recommended by ICRP values for 24-h creatinine excretion, level of daily excreted uranium has been calculated 6.45 ng d-1 (median value). These data along with literature data on uranium dietary intake for Japanese populations were used to estimate uranium gastrointestinal absorption fraction (f1). The median f1 value was calculated to be 0.007.