Risk of urinary tract cancer from exposure to arsenic in drinking water.

Arsenic is found naturally in the environment and is known to cause cancer. Nova Scotia bedrock contains particularly large amounts of arsenic. Arsenic can enter surface and groundwater supplies and affect the health of people who rely on wells for their drinking water. In Nova Scotia, half of the population draw their drinking water from unregulated wells. In some areas of the province, the amount of arsenic in well water has been reported to be up to 100 times higher than the advisory limit set by Health Canada. However, the health risks associated with arsenic exposure in Canada are not known. Studies from elsewhere (e.g. Taiwan, Argentina, Chile, United States) show that high levels of arsenic in drinking water can cause cancers including those of the bladder and kidney. The occurrence of bladder and kidney cancer in Nova Scotia is amongst the highest in Canada. This research aims to measure the risk of developing bladder and kidney cancers as a result of drinking well water containing arsenic in Nova Scotia, Canada. It will also examine how other factors such as age, sex, body size, socio-economic status and lifestyle may influence the relationship between cancer risk and arsenic. To do this, data from the Provincial Cancer Registry and arsenic information from various government departments will be used. In addition, data on arsenic in the tap water and toenails of 5,000 people in Nova Scotia will be studied. This information will be used to show the relationship between the amount of arsenic in tap water and arsenic body burden, a necessary step to link arsenic exposure to cancer risk. The proposed research aims to improve the health of Nova Scotians and Canadians in general. It will support health and environmental policy; inform the public on the potential risks of well water supplies; and guide the development of a risk reduction strategy.