Mercury Pollution Effects, Sources, and Solutions
As Minnesotans, mercury has a special place in our hearts as one of our most hated pollutants. It finds its way from our coal burning power plants to our soil and water. Here, bacteria convert it in to methylmercury and it enters the food chain through aquatic plants and organisms. It eventually accumulates in larger predatory fish,
notably the delicious walleye, our official state fish.
In the past couple of decades, the amount of mercury being emitted by coal-fired power plants has been decreasing, but as is illustrated by the fish consumption advisories regularly issued throughout our region, there is much room for improvement. There are some mercury specific controls close to being ready for wide scale implementation that would drastically decrease emissions. Currently, the most widely studied of these is activated carbon injection. With this technology, powder activated carbon (PAC) sorbent is injected in to the flue gas before it reaches the particulate matter control device. The mercury is adsorbed by the PAC and collected along with the particulate matter.
The Presque Isle Power Plant in Marquette, MI will be the first to implement a full-scale commercial demonstration project for activated carbon injection when the project is completed in 2009.
We would like to get some response as to what effects, if any, the Duluth community has had with mercury levels in fish.
Below is a post from the MN DNR as to the recommended maximum amount of fish which can be consumed from Fish Lake, located just north of Duluth.
Fish Consumption Advisory
Meal Advice for Pregnant Women, Women who may become pregnant and Children under age 15
Species: Walleye
less than 20" : 1 meal per week
20" to 30" : 1 meal per month
Meal Advice for the General Population
Species: Walleye
less than 15" : Unlimited
15" to 25" : 1 meal per week
25" to 30" : 1 meal per moth
Additional lake information is contained in the MN DNR website.
Comments
Seeing Mercury warnings for lakes in the middle of the BWCAW years ago really brought this home for me, and now, as I have children, I will not let them eat certain species, and severely limit their intake of others.
I'm also quite concerned about the effect of climate change, with indications that due to warmer summer temperatures, more mercury will be converted to methylmercury in our lakes, and be available for uptake.
Local Hg controls are important, but much of our Hg is coming from coal plants across the world; take a look in any store, and you can see what this coal-fired power is being used to make: everything from toasters to MP3 players that we buy.
Posted by: Jesse | February 11, 2008 1:08 PM
There was an article in the paper last week about a large decrease in hunting and fishing activities among the US population. I couldn't help but wonder if it was due to these contaminants in the environment. I know it has reduced my interest in fishing.
Posted by: Steve Sternberg | February 12, 2008 10:09 AM
From what I've heard, in Northern Minnesota most of the Mercury pollution that affects are fish populations comes from the soil, absorbed from trees, when these trees die the Mercury is released and free to flow into local lakes, streams, ect. I was wondering, is there information on how much of the Mercury pollution in northern Minnesota comes from power sources?
Posted by: Michael Claussen | February 24, 2008 3:25 PM
That makes sense, the trees could absorb it from the atmosphere before it could reach the soil. There's a link to an MPCA document that partially answers Mike's question. It looks like about 2/3 of the total mercury pollution is man made and at least in Minnesota, half of that is from energy production.
http://proteus.pca.state.mn.us/publications/p-p2s4-06.pdf
Posted by: Luke Schoenecker | February 26, 2008 12:14 PM
Your post is a little off. Minnesota's Mercury pollution doesn't come from "our coal burning power plants." 30% of it comes from other states, 30% of it comes from other countries (China's pollution is particularly egregious), and another 30% of it is from natural emissions. That leaves Minnesota sources responsible for only 10% of the Mercury. Coal power plants contribute less than half of that (about 5% of the total), with taconite production and product disposal accounting for the rest.
The moral of the story--the efforts to clean up and reduce power from our coal fired power plants is an important step, but it will make almost no difference. Mercury pollution is a big problem for Minnesotans, but is not one for which we're primarily responsible.
If we want our lakes and waterways--and the fish we get from them--to be safe and clean, we need to push for national and international controls on Mercury.
Posted by: Brandon | March 2, 2008 1:49 PM