Methylmercury (MeHg) is a potent neurotoxin capable of crossing the blood-brain barrier causing a profound negative impact on the central nervous system. After its release, Hg may be transported worldwide and eventually deposited in colder Arctic regions. Exposure of Aboriginal communities to MeHg occurs primarily through the consumption of traditional food. Dietary exposure studies are conducted using the total concentration of mercury in the food multiplied by the food consumption rate. This method does not take into account the oral bioavailability of Hg. Therefore, this study determines the bioavailability of Hg in four key traditional foods to provide a better estimation of Hg exposure and to improve the characterization of overall Hg risk to human health. We found that Hg concentrations significantly decreased for all foods after undergoing an in-vitro digestion process. Hg bioaccessibility percentage of ringed seal liver was 32.3%, ringed seal muscle was 69.0%, lake trout muscle was 28.8%, and lastly air-dried beluga muscle was 34.0%. Furthermore, no relationship was observed between bioaccessible Hg concentrations and original Hg concentrations in the raw food. The concentration of MeHg in the bioaccessible fraction was also examined and found to be significantly higher in muscle tissues than in the liver. Bioavailability of the foods was determined using Caco-2 cells. Hg bioavailability percentages were found to be 0.42% for RSL 5.24% for RSM, 7.30% for ADB, and finally, 12.70% for LT. Correlations were found between increased Hg uptake and higher percentages of bioaccessible MeHg as well as lower concentrations of bioaccessible selenium. Lastly, a significant decrease in MeHg uptake after 24 hours was observed when co-incubating with selenium. These results suggest that risk assessments should incorporate bioaccessibility and bioavailability when estimating mercury exposure. Additionally, nutrients such as selenium in traditional food may play a role in reducing mercury uptake in the gut.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/36037 |
| Date | January 2017 |
| Creators | Yassine, Rami |
| Contributors | Chan, Laurie |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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