Benzo(a)pyrene-blood protein adducts in wild woodchucks used as biological sentinels of environmental polycyclic aromatic hydrocarbons contamination

Abstract

Levels of benzo(a)pyrene-diolepoxide (BaPDE)-albumin and BaPDE-hemoglobin adducts in wild woodchucks (Marmota monax) have been measured to evaluate the potential usefulness of these parameters in the assessment of environmental contamination by polycyclic aromatic hydrocarbons (PAHs). Blood was obtained from nine woodchucks living near an aluminum electrolysis plant, contaminated area (Saguenay region, Québec, Canada), and from eight living in a control area (Saint-Roch-des-Aulnaies, Québec, Canada). Blood samples were collected and plasma separated from red blood cells by centrifugation on site. Isolation of albumin (Alb) and hemoglobin (Hb) was performed in our laboratory and each protein fraction was subjected to mild acid hydrolysis yielding free benzo(a)pyrene (BaP) tetrol from the adducts. The analysis was performed by high performance liquid chromatography (HPLC) using fluorescence detection. For the control and contaminated areas geometric mean (interval) Alb adduct levels were 7.6 (0.8-29.3) and 69.6 (10.0-1,103) pmol tetrol/g protein (p less than 0.01) while the corresponding figures for Hb adduct levels were 0.40 (0.01-2.72) and 1.18 (0.02-12.8) pmol/g protein (p greater than 0.01). Alb but not Hb adduct levels were associated with the measured concentration of BaP in the vegetation samples collected on the site where each animal was found. This is compatible with the short half-life of Alb adducts and with the instantaneous image provided by BaP measurements in the collected vegetation samples. BaPDE-blood protein adducts measured in wild animals appear to be good biomarkers of environmental contamination by PAHs.