Drinking water supplies are only contaminated by human activity, such as pesticide run-off from farms and chemical spills. Drinking water comes from freshwater lakes, streams, and underground aquifers. These drinking water sources may contain naturally occurring substances, some of which are harmful to humans.
Water can contain decaying vegetation, causing humic and fulvic acids.
Rock formations in the earth can leach naturally occurring substances like arsenic, cadmium, iron, manganese, and uranium into water. Acidic precipitation is making water more corrosive, increasing its ability to leach contaminants from rocks and metallic surfaces. Yes, depending on where you live in Nova Scotia. The presence of low levels of arsenic, a known human carcinogen, in drinking water from private wells is a matter of concern. Arsenic is a naturally occurring element that is widely distributed in the Earth s crust and is present in trace amounts in all living matter.