What is a contaminant?

When most people think of contaminants, they think of some nasty chemical that’s polluting the land or water; something that leaked out of a tank somewhere; that was illegally dumped along some lonesome road in the middle of the night; or that is the result of the manufacture of some industrial chemical. And in some instances, any or all of those scenarios may very well lead to contamination of the water supply. But if you look at the EPA web site where they discuss and list all of the “contaminants” that they currently regulate in drinking water, ( http://water.epa.gov/drink/contaminants/basicinformation/index.cfm ), you will also find a lot of compounds that are naturally occurring; no one dumped them, manufactured them, or otherwise “polluted” the environment with them. They are every bit as much a part of the environment as the water itself. That doesn’t mean they can’t be harmful – arsenic is naturally occurring, but ingest enough of it and it can still kill you. Contrary to so many marketing campaigns that make you believe that “natural products” are somehow inherently safe, they can in fact be just as, if not more harmful than anything created by man. When I was taking Botany in college, someone asked my professor what the definition of a weed was. His response was that a weed is any plant that is somewhere you don’t want it to be. Likewise for drinking water, saying something is a contaminant doesn’t mean it’s the result of some toxic spill or other pollution. It means that, no matter what the source, it’s just something in the water that we don’t want there at more than a certain level.