Sc. Foo et al., METALS IN HAIR AS BIOLOGICAL INDEXES FOR EXPOSURE, International archives of occupational and environmental health, 65(1), 1993, pp. 190000083-190000086
Hair samples from three groups of occupationally exposed subjects were
analyzed for their lead (Pb), manganese (Mn) and mercury (Hg) content
s. For lead (number of subjects, n=209), the hair Pb ranged from 0.93
to 3527 mug/g (geometric mean, GM=641) and blood Pb from 33.3 to 774 m
ug/l (GM=341); for manganese (n=38), the hair Mn ranged from 0.20 to 5
2.97 mug/g (GM=2.66) and urine Mn ranged from 1.70 to 17.9 mug/l (GM=5
.56); and for mercury (n=85), the hair Hg from 1.79 to 12.8 mug/g (GM=
5.09) and the blood Hg from 0.63 to 57.3 mug/l (GM=10.9). The hair Pb
was significantly (P<0.0001) correlated to blood Pb (r=0.85); the hair
Mn to urinary Mn (r=0.45); and the hair Hg to blood Hg (r=0.53). The
average metal content at the distal end was not significantly (P>0.05)
different from that of proximal end. The GM levels for the distal end
were 223 mug/g (95% CI 152-347) and 2.26 (95% CI 0.97-5.29); and thos
e for the proximal end were 186 (95% CI 97-261) and 1.18 (95% CI 0.54-
2.58) for Pb and Mn respectively. However, linear regression analysis
of hair metal levels in the proximal end with respect to those in the
distal end after logarithmic transformation showed that hair Pb in the
proximal end was related to hair Pb in the distal end with a slope of
0.95 (95% CI 0.89-1.01) whereas hair Mn in the proximal end was relat
ed to that of the distal end with a slope of only 0.52 (95% CI 0.13-0.
91), reflecting the relatively constant Pb exposure as compared to the
dropping Mn exposure in recent years. Metals in hair are suitable bio
logical indicators for exposure and the distribution along the differe
nt segments of hair strands reflects the time history of exposure.