High Mercury Content
The Grassy Narrows & Islington Bands Mercury Disability Board

Methylmercury – A Dangerous Chemical

Mercury is an element. An element is a substance that cannot be broken down chemically into a simpler form, for example, hydrogen, or oxygen. These elements can be changed by a scientist, who has special knowledge, to form water. They can also be changed by a totally natural process. Water is a compound. It is a substance formed when more than one element is changed chemically, as happens when hydrogen, an element, is combined with another element, oxygen, to form water, a compound. In the case of methylmercury, mercury joins with carbon and hydrogen to form methylmercury.

This transformation, or change, happens by a process called methylation. Bacteria in river sediment cause mercury deposited in wastewater from chemical plants, such as the Dryden Mill, to change into this poisonous compound. Live creatures, such as fish and shellfish, eat it. Humans and animals in turn eat them. If the poisons are of a sufficiently high concentration, they can be harmful to both.

Animals and humans, who had eaten a lot of fish over a long period of time, were seriously affected. The Dryden Mill dumped a lot of chemical waste, or effluent, into the rivers. The poison that resulted was very harmful to the food in the food chain eaten by residents of the English – Wabigoon River systems.