Mercury, arsenic and selenium exposure levels in relation to fish consumption in the Mediterranean area

In order to assess mercury (Hg), selenium (Se) and arsenic (As) exposure in the Mediterranean area, total mercury (THg), monomethylmercury (MeHg), Se and As levels were measured in umbilical cord blood and breast milk from Italian (n=900), Slovenian (n=584), Croatian (n=234) and Greek (n=484) women. THg, MeHg, As, and Se levels were also determined in blood samples of the same mothers from Italy and Croatia. In addition, THg and MeHg were determined in the same women's hair from all the countries involved in this study and As and Se levels were determined in the mother's urine samples from Italy, Croatia and Greece. Besides recording the consumption of other food items, the frequencies of fish consumption were assessed by detailed food frequency questionnaires, since fish represents an important source of Hg, Se and As in humans. The highest levels of THg and As were found in cord blood (Med(THg)=5.8 ng/g; Med(As)=3.3 ng/g) and breast milk (Med(THg)=0.6 ng/g; Med(As)=0.8 ng/g) from Greek women, while the highest Se levels were found in cord blood (Med=113 ng/g) from Italy. Significant linear correlations were found between Hg, Se and As in blood, cord blood and breast milk. In addition, significant relations were found between the frequencies of total fish consumption and biomarkers of As, MeHg and Se exposure, with the strongest Spearman rank coefficients between frequencies of total fish consumption and THg levels in cord blood (rs=0.442, p<0.001) or THg levels in hair (rs=0.421, p<0.001), and between frequencies of total fish consumption and As levels in cord blood (rs=0.350, p<0.001). The differences in Hg and As exposure between countries were probably due to different amounts of fish consumption and the consumption of different species of fish of different origin, while the highest Se levels in women from Italy were probably the consequence of the more frequent consumption of different non specific food items. Moreover, fish consumption, the possible common source of As, Hg and Se intake, could explain the correlations between the elements determined in cord blood, mother's blood or breast milk.

► Significant linear correlations between biomarkers of Hg, Se and As exposure.
► Significant relations between frequencies of fish consumption and biomarkers of Hg, As, Se exposure.
► The strongest correlations between frequencies of fish consumption and THg in CB or hair, As levels in CB.
► Almost 100% of MeHg in cord blood and hair, and variable % of MeHg in breast milk.
► The lowest % of MeHg in breast milk from Greece.