Metal environmental contamination within different human exposure context- specific and non-specific biomarkers.

Exposure to high levels of persistent pollutants, such as metal mixtures, is commonly encountered by the general population especially in industrialized countries. The aim of this work was to evaluate how metal pollution in contaminated areas is reflected in terms of biomarkers (BMs) of exposure and effect in human sub-populations living in distinct non-occupational environmental contexts. Thus, four Portuguese sub-populations living in different areas of Portugal were studied: i- the exposure of each member of these sub-populations to lead (Pb), manganese (Mn) and arsenic (As) was evaluated by determining metal levels in urine; ii- biochemical changes were assessed, establishing the levels of urinary metabolites of heme biosynthesis; iii- the ability of combinations of these BMs to predict the context of exposure of each subject was tested, as to develop a tool to identify adverse health effects in these environmentally exposed populations. Concerning the combinations of BMs, heme precursors in urine (delta-aminolevulinic acid and porphyrins), were predictive of contexts of environmental exposures, with 94.2% of the studied subjects correctly identified as to their sub-population origin. The use of non-specific BMs may affirm the exposure to Pb, Mn and As, also reflecting health effects induced by a chemical environmental mixture. Our studies affirm the difficulty in establishing a metal reference population.