[Reference values of chromium urine in the population residing in Lombardy]

The accurate determination of Cr in normal human urine still presents a considerable challenge, connected to its very low content, supposedly about 1 ppb. The analytical data obtaining from many Authors varying between 0.3 microgram/day and 150 micrograms/day. The question now arises which data picture the true Cr content of normal human urine. To this purpose we have determined the content of total urinary chromium in 310 healthy individuals (170 male, 140 female) resident in Lombardy (Italy). A mean urinary Cr concentration of 0.59 +/- 0.26 ppb was obtained. The levels of urinary chromium tended to be higher in males than in females and to decrease with age.