Bioaccessibility and speciation of arsenic in country foods from contaminated sites in Canada

Abstract

Arsenic in foods obtained through foraging or hunting (country foods) in contaminated areas has not been reported; moreover the chemical form (arsenic speciation) is not known. Bioaccessibility extractions can be used to extract the arsenic from samples, giving information about the arsenic that is available for absorption into humans. Bioaccessibility of arsenic was measured in country foods (berries, other plants, mushrooms and hares) collected from contaminated sites in Canada. Arsenic speciation in the bioaccessibility extracts was also determined. Arsenic concentrations in berries ranged from 0.06 to 21 mg/kg, and Labrador tea contained 1.9 mg/kg of arsenic (all wet weight). Arsenic concentrations (wet weight) ranged up to 46 mg/kg in mushrooms, but they were much lower in hare muscle tissue (0.007 to 0.6 mg/kg). Percent bioaccessibility was lowest in berries and plants (means of 12-45%), where the arsenic species were mostly toxic inorganic arsenic. Bioaccessibility was higher in mushrooms and hare meat (means of 22-76%), where along with toxic inorganic arsenic, substantial proportions of less toxic organoarsenic species were measured, including non-toxic arsenobetaine. The speciation patterns were highly variable in both mushrooms and hare meat. Toxic forms of arsenic are present in country foods collected from contaminated areas, but the amounts vary according to and within each sample type. Therefore testing should ideally be carried out for new sample types and locations to estimate exposures to humans.