At a January fundraiser in Banff, Robert F. Kennedy suggested that 90 percent of Alberta's fish are unsafe to eat, inciting controversy across Alberta. In subsequent interviews, Kennedy clarified that he was talking about mercury in fish. Kennedy's Waterkeeper Alliance organization has an international campaign dedicated to highlighting the impacts of mercury to human health and fish. They are seeking to clean up sources of air borne mercury such as from coal-fired power plants.

Water Matters decided to investigate this comment to better understand the issue of mercury in fish in Alberta.

The story behind the story

There are 17 consumption advisories in Alberta recommending that women (between 15 and 49 years old) and children (under 11 years old) not eat fish due to mercury contamination. These advisories exist for the entire Athabasca, South Saskatchewan and Oldman Rivers and parts of the Bow River (below Bassano Dam) and Red Deer River (below Dickson Dam) including 10 lakes.

Advisories exist for other rivers in Alberta that indicate the quantity of different fish healthy adults, women, and children can consume. The Government of Alberta and Health Canada recommend that when mercury levels in fish exceed 0.5 parts per million (ppm), women of child-bearing age and children under 11 should avoid eating that fish. Healthy adults may eat limited amounts of fish with these concentrations of mercury. However, concentrations greater than 0.2 ppm are considered high for adult populations who eat a lot of fish such as First Nations.

The most recent advisory was announced by the provincial government last year in October 2009. High levels of mercury in fish prompted Alberta's chief medical examiner to issue a warning. The warning was directed at pregnant women and children for consuming certain types of fish in Pine Coulee, Twin Valley Reservoirs, the Red Deer River (mouth of Blindman River), and the lower South Saskatchewan River near Medicine Hat.

Mercury advisories can be found in the Alberta Guide to Sportfishing Regulation and at www.albertaregulations.ca/fishingregs. Click on the "Helpful Information" menu and go to Mercury Contamination.

More about mercury

Mercury occurs naturally in rocks, soils, and water. Mercury can also originate from burning coal which then deposits into waterbodies. Regardless of its source, once mercury enters a waterway, naturally occurring bacteria absorb it and convert it into a highly toxic substance - methyl mercury.

In general, mercury is a neurotoxin that can impair the nervous system in adults. Chronic exposure to mercury can cause damage to the brain, spinal cord, kidneys, liver and developing fetus. Pregnant women who are exposed to even low concentrations of mercury can bear children with neurodevelopmental problems.

Most people are exposed to mercury from the air, their contact with water, soil, or substances or products containing mercury. However, the greatest exposure to mercury by humans is from the ingestion of food, especially fish.

Sources of mercury

Mercury has always been a part of the natural environment, but industrial activities over the past 100 years have significantly increased the amount of mercury in the atmosphere. Today, the burning of fossil fuels emits more mercury than any other type of human activity.

According to a 2007 study by Vincent St. Louis, a biological sciences professor at the University of Alberta, there is a direct link between mercury emissions (atmospheric deposition, or mercury in the air) and mercury in fish. The study concluded that a reduction in mercury emissions in the air would result in a significant decrease in mercury levels in fish.

"We can say conclusively that if you reduce mercury emissions it will result in less mercury in fish...[the] experiment underscores the importance of immediately reducing atmospheric mercury releases," said St. Louis, (Coal-fired power stations 'poison fish with mercury', The Mail).

In Alberta, little information exists about the amount of naturally occurring mercury versus man-made sources. The Alberta government says most of the mercury in fish likely comes from natural sources in soils and sediments. Natural sources of mercury also include volcanoes, forest fires, and fossil fuels.

But in the United States, mercury contamination in water and fish are increasingly coming from mercury emissions from coal-fired power plants. Across the United States, mercury pollution contaminates 12 million acres of lakes, estuaries, and wetlands (30 percent of the total), and 473,000 miles of streams, rivers, and coasts. By 2003, many of these water bodies posted advisories in 44 states warning citizens to limit how often they eat certain types of fish because of mercury in those fish from state waters. A 2009 study by the U.S. Geological Survey found mercury contamination in every fish sampled in 291 streams across the country. The same study found a quarter of the fish contained mercury levels above the Environmental Protection Agency's threshold safe for human consumption.

While the Alberta government suggests that most mercury stems from natural sources, research such as from the University of Alberta discussed above offers information about the relationship of mercury emissions in lake sediment and higher concentrations in Alberta. A 2006 study evaluated whether coal-fired power plants contributed to mercury contamination for three Alberta lakes. Coal-fired power contributed to higher mercury contamination in lake sediment for Lac Ste. Anne, Wabamun, and Pigeon lakes. Wabamun Lake, which is located near two coal-fired power plants, had the highest increase of mercury contamination.

Kennedy clarifies comment

Government advisories for the consumption of fish due to mercury contamination exist on a large number of rivers and lakes in Alberta. These advisories largely affect women of child-bearing age and children. However there is no official evidence that 90 percent of Alberta's fish are too contaminated to eat. Kennedy defended and clarified his comment in a CTV interview arguing that there are no safe levels of mercury and Health Canada's regulations are wrong. "Here's what I would say to Health Canada: if you want mercury in your fish, any mercury, even a molecule of mercury, you should add it yourself at home," Kennedy said. "But don't put it in fish that the public has to eat, and don't allow polluters to put it into the fish that the public has to eat."

If your view is that there is no safe level of mercury to eat, then Kennedy's comment may be on point. But perhaps the more important lesson is that all Albertans should become aware of mercury contamination in fish. And, we should watch to see how much mercury from coal-fired plants close and far away affect things in the future.

For more information:

Mercury and the Environment, Health Canada.

Mercury Contamination in Fish: A Guide to Staying Health and Fighting Back

Sources

Alberta Sport Fishing Regulations. (accessed January 30, 2010).

Barbara C. Scudder, Chasar, L.C., Wentz, D.A., Bauch, N.J., Brigham, M.E., Moran, P.W., and Krabbenhoft, D.P. 2009. Mercury in fish, bed sediment, and water from streams across the United States, 1998-2005 (U.S. Geological Survey, Washington D.C.) (accessed February 5, 2010).

Coal-fired power stations 'poison fish with mercury'. 2007. The Mail (part of the Daily Mail syndicate), September 17, 2007. (accessed January 30, 2010)

Environment Canada. Fact Sheet. Mercury and the Environment: Fish Consumption. (accessed January 30, 2010).

Donahue, W.F. and E.W. Allen and D.W. Schindler. 2006. Impacts of coal-fired power plants on trace metals and polycylic aromatic hydrocarbons (PAHs) in lake sediments in central Alberta, Canada. Journal of Paleolimnology 35: 111-128.

Government of Alberta, Alberta Health and Wellness. 2009. Common questions about methylmercury levels in Alberta fish. Edmonton Alberta.

Kennedy defends claim that Alberta fish inedible. 2010. CTV.ca. January 27, (accessed January 30, 2010).

Mackenzie River Basin Board (MRBB). 2003. Mackenzie River Basin: State of the Aquatic Ecosystem Report: Whole Basin Overview. (accessed January 30, 2010).

Necheff, Julia. 2007. Study traces mercury pollution in fish. September 17, (accessed January 30, 2010).