Ml. Gargas et al., URINARY-EXCRETION OF CHROMIUM BY HUMANS FOLLOWING INGESTION OF PICOLINATE - IMPLICATIONS FOR BIOMONITORING, Drug metabolism and disposition, 22(4), 1994, pp. 522-529
This study investigated the variability in urinary chromium (Cr) excre
tion following the ingestion of Cr picolinate by human volunteers. A p
harmacokinetic model was used to estimate the bioavailability of Cr fr
om ingested Cr picolinate using known distribution patterns and elimin
ation rates of Cr by humans. The possible advantages of using sequenti
al, individual spot, or 24-hr urine sample collection for biomonitorin
g of Cr exposure were examined. Background concentrations of urinary C
r determined from the spot samples in this study compared well with va
lues reported by others. The variability in urinary excretion of Cr in
untreated volunteers indicated that it is virtually impossible to dis
tinguish exposures to most occupational and virtually all environmenta
l exposures to Cr. Sequential urine sampling was found superior to bot
h 24-hr and spot urine collection for indicating exposure to Cr picoli
nate. The extent of absorption of Cr from the picolinate matrix in the
gastrointestinal tract was 2.80 +/- 1.14% (SD). It was estimated that
10 mg of soil containing between 7,400 and 52,000 mg Cr(III)/kg would
have to be ingested by an adult to result in urinary excretion of Cr
clearly above the upper bound of Cr in urine from background populatio
ns (1.8 mu g Cr/liter), depending on certain assumptions regarding bio
availability. This study supports the results of other recent work tha
t demonstrated urinary excretion of Cr resulting from low-level enviro
nmental exposure is unlikely to be distinguished from that resulting f
rom dietary uptake.