Comparison of the effects of urinary flow on adjusted and non‐adjusted excretion of heavy metals and organic substances in ‘healthy’ men

Abstract

The effect of variation in urinary flow rate (ml urine min⁻¹, UF) on adjusted and non‐adjusted urinary excretion of metals and organic substances was examined in ten ‘healthy’ men. The effect of UF was found to be eliminated when urinary concentrations of lead (Pb), hippuric acid (HA), delta‐aminolevulinic acid (ALA) and coproporphyrin (CP) were adjusted to urinary specific gravity and to UF. Similarly, the effect of UF on inorganic mercury (Hg) was eliminated when the concentration was adjusted to timed excretion and to UF. The effect on zinc (Zn) and copper (Cu) was eliminated when adjusted to urinary creatinine (Cn) and to UF. The difference in the effect of UF on the adjusted urinary excretion was explained by the effect of UF on timed excretion of substance, which was ranked in the following order: Pb, HA, total urinary solutes, ALA and CP; Zn; Cu; Cn; and Hg. It was concluded that ‘UF‐adjusted concentration’ is applicable to measurement of all substances in urine as a method of minimizing UF effects, while the other three adjustment methods have only limited uses.