Research Activities

Foods + Ingested Particles

I4  Dr. Steven Siciliano (P.I.), steven.siciliano@usask.ca
Soil Science, University of Saskatchewan
Human Bioaccessibility of Metals Surrounding Northern Hotspots

Collaborators
Dr. Heather Jamieson (Co-Inv.), jamieson@geol.queensu.ca
Department of Geological Sciences & Engineering, Queen's University
Derek Muir (Co-Inv.)
Dr. Mike B. Parsons (Co-Inv.), miparson@nrcan.gc.ca
Geological Survey Canda, Natural Resources Canada
Derek Peak (Co-Inv.), derek.peak@usask.ca

Current summary: Exposure to metals and metalloids, such as arsenic, lead, and mercury, through the consumption of contaminated foods poses a potential health risk to human populations. This is especially true for Northern communities due to a reliance on traditional backcountry foodstuffs. Measuring the bioaccessible fraction, the amount of an ingested contaminant solubilized in the gastrointestinal tract, may allow risk assessors to better compare people’s exposure to ingested contaminants with toxicological reference values. By resolving the sources of variation of metal bioaccessibility in northern foodstuffs, it will be possible to reduce the uncertainty present in current risk assessments and provide northern communities with precise risk reduction strategies. Additionally, the arsenic and mercury bioaccessibility of mine tailings from Nova Scotia is being investigated to better evaluate the exposure of Nova Scotia residents to toxic metalloids.

Summary Archive: Current | 2007 | 2006

 

Project Metadata

Study/Sampling Design

  • Digestion of mine tailings (bulk and <38 µm fraction) in a static Simulator of the Human Intestinal Microbial Ecosystem (SHIME) with stomach (fasted), small intestine, and colon stages;
  • Measurement of the arsenic and mercury bioaccessibility in the small intestine and colon stages;
  • Use of a sterilized colon stage and re-digested mine tailings to assess role of gastrointestinal microbes in metalloid bioaccessibility;
  • Arsenic and mercury bioaccessibilities expressed as a percentage of the total concentration in the mine tailings;
  • Separation of the bioaccessible arsenic fraction by centrifugation (12,000 g for 20 min) followed by ultrafiltration (10 Kda);
  • Measurement of arsenic in the bioaccessible fraction by hydride generation atomic fluorescence spectroscopy; and
  • Measurement of mercury in the bioaccessible fraction by cold vapour atomic fluorescence spectroscopy.

Number of projects providing material for study: 0

Location of Field Site(s)
--- none provided ---

Human Studies

Outcome or Process Studied
--- none provided ---

Exposure Medium, and Metals/Substances Quantified
--- none provided ---

Biological Endpoint(s) Monitored
--- none provided ---

Biota Studied

Species
--- none provided ---

Metals, etc. Quantified
--- none provided ---

Biological Endpoint(s)
--- none provided ---

Physical Material(s) Studied

Medium/Media
Synthetic gastrointestinal fluids:

Small Intestine:
  • NaHCO3, bile salts (oxgall), pancreatin
Colon
  • SHIME suspension containing gastrointestinal microorganisms (i.e., Lactobacilli, Bifidobacteria, Enterococci, Fungi, Staphylococci and Clostridia)


Metals, etc. Quantified
  • Arsenic - Release (mg As / kg mine tailings) & Bioaccessibility (%)
  • Mercury - Release (mg Hg / kg mine tailings) & Bioaccessibility (%)

Bibliographic References on-file with Secretariat: No

Data Available: Yes

Data Archived with MITHE-SN: No