Huelva (South West Spain) and its surrounding municipalities represent one of the most polluted estuaries
in the world owing to the discharge of mining and industrial related pollutants in their proximity.
A biomonitoring study was conducted to assess exposure to arsenic and some trace metals (cadmium,
mercury, manganese and lead) in urine and scalp hair from a representative sample of children aged
6–9 years (n = 261). This is the only study simultaneously analyzing those five metal elements in children
urine and hair. The potential contribution of gender, water consumption, residence area and body mass
index on urinary and hair metal concentrations was also studied. Urine levels of cadmium and total mercury
in a proportion (25–50%) of our children population living near industrial/mining areas might have
an impact on health, likely due to environmental exposure to metal pollution. The only significant correlation
between urine and hair levels was found for mercury. Children living near agriculture areas
showed increased levels of cadmium and manganese (in urine) and arsenic (in hair). In contrast,
decreased urine Hg concentrations were observed in children living near mining areas. Girls exhibited
significantly higher trace metal concentrations in hair than boys. The greatest urine arsenic concentrations
were found in children drinking well/spring water. Although human hair can be a useful tool for
biomonitoring temporal changes in metal concentrations, levels are not correlated with those found in
urine except for total mercury, thus providing additional information.