Amanda Morin

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Indigenous communities in Canada often struggle with access to clean drinking water. Chlorination is the primary water disinfection method in these communities, but due to high levels of organic carbon in the water pre-disinfection, the likelihood of chloroform formation, a trihalomethane (THM), is significantly increased. In 2019, Eabametoong and Attawapiskat First Nations in Northern Ontario declared a state of emergency due to high levels of THMs, mainly chloroform, in their drinking water. Health Canada supports that the benefits of disinfection through chlorination outweigh the risks of long-term, low-dose chloroform exposure. However, the field is lacking in research on the long-term effects on complex human health outcomes. This study aimed to assess the effects of low-dose chloroform treatment on a biomarker of health, mitochondrial DNA copy number (mtDNA-CN). mtDNA-CN variation is known to be associated with aging, frailty, and mortality. After 48h of low-dose chloroform treatment in HEK293 cells, no dose dependent mtDNA-CN changes were seen. HEK293 cells were then treated with a higher range of chloroform doses for 48hand yielded the same observation of no significant mtDNA-CN variation. Although there were no significant observations, this experiment tested only one biomarker of health in one cell line and was not conducted in a long-term setting, thus conclusions about the long-term health effects of low-dose chloroform exposure require further investigation.