Monday, September 8, 2008

Questions about Mercury and Cement

Whitney K. has gotten us started with two good sources:

1. A presentation from the Binational Toxics Strategy Mercury Workgroup
Toronto, Ontario – May. 17, 2006

2. A July 2008 article from the San Francisco Chronicle

Thanks Whitney!

Note the connection between slide #11 in the presentation and the article content.

Questions:

1. Why is mercury released in cement production (which raw materials contain mercury)?

2. How is mercury released in cement production?

3. How and in what form does the mercury then enter the atmosphere?

4. How and in what form does mercury get absorbed/consumed by humans?

5. What are the potential health effects of mercury ingestion?

6. Is there empirical evidence that these effects are more pronounced in areas adjacent to cement plants?

7. What are the potential solutions?

8. Other questions we should think about?

Some of these are at least partially answered in the sources provided by Whitney, but more info is always a good thing.

Pick a question and go for it. Please cite your sources.

8 comments:

Mandy Isaac said...
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Brad Coffey said...
This comment has been removed by the author.
Brad Coffey said...

I found a journal article that elaborates on the chemical makeup of Mercury and addresses a few of the possibilities to questions 4 and 5 as of the year 2000.

What are the Potential Health Effects of Mercury Ingestion?

In an aquatic environment, inorganic mercury is converted to Methylmercury by methanogenic bacteria present in sediments of fresh and oceanic water. The MeHG is then bioaccumulated and bioconcentrated as it passes up the aquatic food chain. All fish contain some MeHg and vertebrates (fish and sea mammals) at the top of the food chain contain the largest quantities.

MeHg in vitro inhibits microtubule formation and protein synthesis in nerve cells, alters neuronal membrane activity, and interferes with DNA synthesis; In vivo it impairs mitosis and disrupts neuronal migration. Its toxicity has been known for centuries and multiple episodes of poisoning in children by both inorganic and organic have been reported. Organic forms of mercury are particularly neurotoxic. Both prenatal and postnatal exposure to MeHg can adversely affect the central nervous system, but it appears to be most neurotoxic prenatally when the brain is developing rapidly. Exposure to sufficient amounts can cause neurological impairment or even death. However the lowest level of exposure that can produce health effects detectable using epidemiological methods is presently unknown.

(Environmental Health Perspective, Volume 108, Supplement 3, June 2000)

matthew pickett said...

In the proposed construction and mining of limestone for the Titan plant there will be destruction of approx. 500 acres of wetlands, (Doug Springer, cape fear riverkeeper). This destruction will counteract the long time goals of preserving this area, as well as undermine an already fragile system that supports aquatic life and flood mitigation. The opposite side of the river has been an object of conservation groups for quite some time and millions of dollars have been spent to set it aside. Tracy Skrobol of the NC coastal federation is currently gathering data in order to get a full figure on the amount and it should prove to be pretty disturbing when on the other side of the waterway the intense mining of limestone and cement production will prove to "destroy the island creek region"(Doug Springer). On a side note it has been communicated to me that our regional limestone contains a chemical more hazardous in production than that of traditional. When I recieve the name of which and the chemical process I will include.--matthew pickett

Mandy Isaac said...

#1 and 2: Mercury emissions in cement production mainly come from two sources. One is the because limestone, one of the main ingredients used to produce cement, contains mercury that is emitted while it is burned with other ingredients to form the clinker used to make cement. The other primary source of mercury emissions is the fossil fuels used to heat the chemicals. Coal is often used as a fossil fuel in the process and it emits a significant amount of mercury during the process.

#4 and 5: Mercury is absorbed through humans through direct physical contact with the chemical, breathing when it is emitted into the air, as well as through the consumption of fish that contain high levels of mercury. The main group affected by mercury is unborn babies and children. If a pregnant woman consumes too much mercury during pregnancy, there will most likely be a profound effect on the baby’s brain and nervous system, resulting in severe disabilities. Adults also are at risk for mercury poisoning through consumption, whose symptoms include “impairment of the peripheral vision; disturbances in sensations ("pins and needles" feelings, usually in the hands, feet, and around the mouth); lack of coordination of movements; impairment of speech, hearing, walking; and muscle weakness.” (http://www.epa.gov/mercury/effects.htm). Inhalation of mercury is a concern for Wilmington residents with the proposed 263 pounds of Mercury that Titan Cement Plant will emit each year if the project passes. Symptoms of this type of mercury exposure include, “ tremors; emotional changes; insomnia; neuromuscular changes (such as weakness, muscle atrophy, twitching); headaches; disturbances in sensations; changes in nerve responses; performance deficits on tests of cognitive function. At higher exposures there may be kidney effects, respiratory failure and death.” (same as above source).

#6: A study conducted by The University of Texas Health Science Center at San Antonio found that for every 1000 pound of mercury released there is a 17% increase in autism rates. (Wrightsville Beach Magazine September 2008).

Whitney Knapp said...

While this doesn't specifically relate to cement, I found some information about a fertilizer plant in Japan that released large amounts of mercury into the water. This caused several thousand residents to suffer from mercury poisoning, as well as death.

I couldn't find one article in particular that has a lot of information, but if you go on Wikipedia (not the most reliable source, i know)and search for Minimata disease they have a lot of information.

steve burke said...

Ok, this article I found speaks to several of the questions, and the source is OregonLive.com, or the link is http://blog.oregonlive.com/breakingnews/2008/02/2006richard_cocklethe_oregonia.html
if you would like to read the entire piece. Basically there is a cement plant in Oregon that is voluntarily introducing a control system to capture 75 percent of its current mercury emissions using a very new technology...here are a few bits of the info:

"Ash Grove Cement near Baker City, by far the largest mercury polluter in Oregon and the state's only cement kiln, has reached a voluntary deal with regulators to cut its mercury emissions by 75 percent within 3½ years.... The agreement between Ash Grove and the state Department of Environmental Quality requires the company to install controls within two years for a cost estimated at $15 million to $20 million....Eighteen months after that, Ash Grove's mercury reduction goal will be 85 percent, with a fallback target of 75 percent. If its capture rate falls below 75 percent the company could face civil penalties...Ash Grove mines limestone, slate and clay from a quarry near its plant in Durkee, southeast of Baker City. It bakes those ingredients and iron slag in a kiln at temperatures approaching 3,000 degrees, producing about 1 million tons of "clinker," a precursor to cement, each year. The process sends gas containing mercury up the kiln's 290-foot-tall main smokestack... The center injected particles of activated carbon into the emission stream. The mercury attached to the carbon, which was then captured in a series of filters. The tests concluded that the technology, already used in coal power plants, would capture 65 percent to 90 percent of mercury emissions, depending on operating conditions. That led the company, regulators and the advisory committee -- which included doctors, toxicologists, environmentalists, local and company officials and a tribal representative -- to agree that a 75 percent reduction was a fair target...Operating the system will cost $2 million to $4 million a year, the company estimates. It also will require hauling 400 to 1,000 tons a year of activated carbon, made from coal, to a landfill."

That is the basic idea, and it is good to know that there are possiblities for reducing the amount of mercury released, but the system is completely voluntariy and with the hundreds of tons of activated carbon going to the landfill each year it still has its drawbacks.

Brad Coffey said...

I was searching for potential solutions to mercury emissions and came across a potential abstract solution. There are some instances where dietary selenium (Se) has reduced the toxicity of mercury/methylmercury in animals. This article mentions rats, I also came across a different article showing experiments on quail in Japan. This journal states there is no evidence suggesting that this works with humans, but it's possible they're on to something.

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