In the present study, girls exhibited significantly higher concentrations
of trace metals in hair than boys , thus supporting
previous reports . This observation can be accounted
for by the different growth rate of hair among individuals since a
larger trace metal accumulation is expected with a slower rate of
hair growth. Nevertheless, there are some controversial
results as Olivero-Verbel et al. and Sanna et al.
found males with significantly greater Hg and Pb levels than
females.
The greatest urine As concentrations were found in children
drinking well or spring water (Table 3). Liu et al. (2010) suggested
that different As concentrations in drinking water could influence
arsenic levels in children. Although trace metal levels have been
related with the area of residence, our study found that living in
urban, metropolitan or rural areas does not contribute significantly
to metal concentrations in urine except for Hg. This finding was
also reported by Aguilera et al. (2010) near our study area.
The correlation between metal levels in hair and other biological
samples, such as blood or urine, used for the assessment of
environmental exposures, has been previously addressed for biomonitoring
purposes . Our results have found a
correlation between urine and hair trace metal concentrations only
for mercury . However, while hair content is related to
past exposures, urinary levels reflect recent exposure except for
Cd. This toxicokinetic difference may account for the lack of correlations
found in this study.