2.2. Blood Hg, Se and long-chain n−3 PUFA analyses
Total Hg and Se concentrations were determined in whole blood.
Total Hg in whole blood is a validated biomarker of recent intake and acceptable
surrogate of MeHg exposure given the elevated consumption
of fish and marine mammals in this study population (Kershaw et al.,
1980). Whole blood samples were collected from an antecubital vein
in a 6 mL plastic vacutainer containing potassium EDTA as the anticoagulant
(BD Medical), stored frozen at −80 °C and sent to the Centre de
Toxicologie du Québec of the Institut National de Santé Publique du Québec
for total Hg and Se determination by inductively coupled plasma mass
spectrometry. The detection limit for blood Hg and Se was respectively
0.1 and 7.9 μg/L. The complete analytical method is detailed elsewhere
(Valera et al., 2009). The long-chain n−3 PUFA composition of
the erythrocyte phospholipids (eicosapentaenoic acid (20:5; EPA),
docosapentaenoic acid (22:5; DPA) and docosahexaenoic acid (22:6; DHA)) was measured after membrane purification, chloroform/
methanol lipid extraction, and methylation of fatty acids, followed
by capillary gas–liquid chromatography using a DB-23 column
(39.0 × 0.25 mm ID × 0.25 μm thickness) in a Hewlett–Packard gas
chromatograph. The results are expressed as percentage of total
fatty acids and the complete analytical method, described in Lucas
et al. (2010c).