Kennedy defends claim that Alberta fish inedible

Isn't there a naturally occuring mercury?

Yes. It seeps from the ground and can be found in both the plants and the fish. As far as my understanding freshwater fish in north america contain a level of mercury.

This is a classic example of "who-knows-what". Kennedy appears to be suggesting that mercury level makes fish inedible in which case you can't eat North American fresh water fish. Period. Alberta or Arizona doesn't matter. The "environmental groups" seems to be admitting that Kennedy is misinformed with out directly addressing the question "do fresh water fish contain a certain level of mercury naturally" which I believe is yes and I believe the environmental groups understand this. Seems they dodge the question in the article and just go straight to explaining why higher levels of mercury could be found as a result of oil sands production, waste (mis)management etc.

Well, technically, all mercury is naturally occurring.

There are, of course, background levels in water streams and they rise and fall depending on many factors, most signficantly the content of mercury ores (cinnebar, in particular) in the surrounding geology. Mercury (actually it's metabolite methyl mercury) is an acute neurotoxin at low concentrations, like many heavy metals.

In mines you get acid rock drainage, whereby water and oxygen react with primarily sufides (normally biocatalyzed) to produce sulphuric acid in solution. Consequently, you get a drop in pH of your mine effluent. Metals are typically more soluble in acid, so you get a lot of metals, such as mercury, going into solution and your dissolved metals concentrations go up in your local waterbodies.

Mercury bioaccumulates (tends to build up in an organism with increased exposure) and biomagnifies (tends to increase in concentraiton in organisms as you move up the food chain).

There is no safe exposure limit to mercury, but that's not really saying much becasue there isn't really a safe exposure level to thousands of chemicals and products--like wood dust or gasoline fumes.

Hatters used to use mercuric nitrate whihc would have nasty neurological impacts on them, thus the term "Mad as a Hatter."

Study Finds Mercury Contamination in Freshwater Fish Nationwide

Department of Interior press release:

WASHINGTON, D.C. – Scientists detected mercury contamination in every fish sampled in 291 streams across the country, according to a U.S. Geological Survey study released [August 19, 2009].

About a quarter of these fish were found to contain mercury at levels exceeding the criterion for the protection of people who consume average amounts of fish, established by the U.S. Environmental Protection Agency. More than two-thirds of the fish exceeded the U.S. EPA level of concern for fish-eating mammals.

“This study shows just how widespread mercury pollution has become in our air, watersheds, and many of our fish in freshwater streams,” said Secretary of the Interior Ken Salazar. “This science sends a clear message that our country must continue to confront pollution, restore our nation’s waterways, and protect the public from potential health dangers.”

Some of the highest levels of mercury in fish were found in the tea-colored or “blackwater” streams in North and South Carolina, Georgia, Florida and Louisiana — areas associated with relatively undeveloped forested watersheds containing abundant wetlands compared to the rest of the country. High levels of mercury in fish also were found in relatively undeveloped watersheds in the Northeast and the Upper Midwest. Elevated levels are noted in areas of the Western United States affected by mining. Complete findings of the USGS report, as well as additional detailed studies in selected streams,

In my opinion Robert Kennedy is just trying to find himself an audience. A lot of folks down here when they here when they meet him after they get over the initial attraction to his name realize he is just completely full of shit and looking for a cause so that people can take him seriously, so far not much success.

Rule #1 of Modern Environmentalism: your celebrity spokesperson is NEVER wrong!

*** just full of hot air ***