Air Quality Criteria for Lead Volume II of II - (NEPIS)(EPA) - US ...

AX5-141
Table AX5-8.4. (cont’d). Bone Lead as a Potential Source of Toxicity in Altered Metabolic Conditions
Compound
Dose/Concentration
Duration Exposure
Route Species Effects Blood Level Reference
Pb acetate
250 mg/l
Exposure for 5 wks
Drinking water
Pb acetate
250 µg/l
14 days
Drinking water
Abbreviations
µg—microgram
mL—milliliter
%—percent
mM—millimolar
l—liter
ppm—parts per million
dL—deciliter
Rat Rats were exposed to Pb for 5 wks, followed by a 4 wk washout period
without Pb to allow primarily accumulation in the skeleton. Rats were then
randomly assigned to a weight maintenance group (WM), a moderate weight
loss (MWL) group (70% of maintenance diet), or a substantial weight loss
(SWL) group (40% of maintenance diet) for a 4 wk period. At the end of this
experimental period the blood and bone levels of Pb did not differ between
groups, however, the amount and concentration of Pb in the liver increased
significantly.
Treatment Group Pb (nmol/g)
Femur WM 826 ± 70
MWL 735 ± 53
SWL 935 ± 84
Spinal Column Bone WM 702 ± 67
MWL 643 ± 59
SWL 796 ± 59
Rat Study was undertaken to determine the effect of weight loss and exercise on
the distribution of Pb. Weight loss secondary to dietary restriction was a
critical factor elevating organ Pb levels and, contrary to prior study (Han et al.
(1996)), elevated blood levels of Pb. No significant difference in organ or
blood Pb concentrations were reported between the exercise vs. no exercise
groups.
WM = 1.25 ± 0.10 µM;
MWL = 1.16 ± 0.10 µM;
WM = 1.32 ± 0.10 µM;
Graphs indicate
concentrations ranging
from 0.20 to 2.00 µM.
mg—milligram
µM—micromolar
Pb—lead
kg—kilogram
g—gram
204 206 207
Pb, Pb, Pb—Stable isotopes of lead 204, 206, 207, respectively
wt—weight
ppb—parts per billion
Han et al. (1996)
Han et al. (1999)