Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Pathology

Supervisor(s)

Dr. Jack Bend

Abstract

This project is an interdisciplinary, community-based, participatory Ecosystem Health investigation with two First Nations in Canada, one located in the far south (Walpole Island; WIFN) and one in the far north (Attawapiskat; AttFN), and a large Kenyan community surrounding Lake Naivasha. The increased human health risks from exposure to three classes of environmental contaminants, persistent organic pollutants (POPs), pesticides and metals, and fear from such exposures are pressing concerns in each setting. Sensitive analysis of 15 metals in hair, six metals and 91 POPs in whole blood or serum of WIFN and AttFN volunteers has been conducted. Whole blood samples from volunteers in Naivasha were assayed for erythrocyte cholinesterase, a biomarker of exposure to anticholinesterase pesticides. Chronic stress was measured in all three communities with the biomarker cortisol in hair. The concentration of most of the metals in hair and of POPs in serum of AttFN volunteers are higher than at WIFN, possibly as a result of long-range atmospheric transport. These data indicate an enhanced risk for adverse health effects at AttFN, including Type 2 diabetes. There was no evidence for increased occupational exposure to anticholinesterase pesticides in flower farm workers at Naivasha, the hub of the floriculture industry in Kenya. We found increased hair cortisol concentrations among volunteers from AttFN compared to WIFN, which in turn were both higher than volunteers from a non-First Nation community in Canada. There were increased hair cortisol concentrations in volunteers from the Kenyan slum communities compared to Kenyan clinical team members and our reference group of Caucasians in Canada. The cause for this enhanced stress at WIFN, AttFN and in the Kenyan settlement communities is probably a combination of the fear of exposure to environmental contaminants, socio-economic conditions and poorer health. These are considered to be vulnerable populations because they have increased exposure to toxic contaminants and increased stress compared to the general Canadian population. In all three communities, an understanding of the real, current links between exposures to contaminants (through biomonitoring people) and health risks, as opposed to chemophobia, will empower community members to make decisions that will benefit their health and reduce stress.


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