Adjustment of urinary concentration to urinary volume in relation to erythrocyte and plasma concentrations: an evaluation of urinary heavy metals and organic substances.

The effects of urinary volume on adjusted and nonadjusted urinary excretion of 11 heavy metals and organic substances were examined in relation to plasma and erythrocyte concentrations in 19 metal workers under conditions of water restriction and loading. Blood lead concentrations in these workers ranged from 25 to 59 micrograms/dl. The results indicated that: urinary volume significantly affects not only nonadjusted urinary concentration for all substances, but also affects timed excretion and concentrations adjusted to urinary specific gravity and to urinary creatinine for most substances; the concentration adjusted to urinary volume is, on the other hand, independent of urinary volume; and urinary excretion of lead and mercury is related more closely to erythrocyte concentration than to plasma concentration. This last finding reflects complex renal excretory mechanisms for these heavy metals.