One thing that has been missed by many working on mercury exposure and toxicology issues is that risks associated with elemental mercury exposures may be greater than had previously been anticipated.

High elemental and methylmercury exposures cause neurotoxicity because mercury is a highly specific irreversible inhibitor of vital, but highly vulnerable selenoenzymes that are required by the brain to prevent and reverse oxidative damage. Because of its high rate of oxygen consumption, the brain produces reactive oxygen species at rates that are much higher than in other tissues. However, functionally elite selenoenzymes are present in the brain (actually throughout the neuroendocrine system), these reactive oxygen species are quenched before they can cause harm and much of the oxidative damage that does occur is rapidly reversed by other selenoenzymes. Since enzyme inhibition is, by definition, a bimolecular chemical reaction, both components in the equation (mercury and selenium) need to be assessed or the outcome of the equation cannot be guessed.

Understanding this makes it easy to comprehend why predictions of neurological harm from methylmercury exposures from ocean fish consumption were inaccurate. Those predictions were based on the observed effects of maternal consumption of pilot whale and shark meats (the only foods know to commonly contain far more mercury than selenium) and the assumption that the molecular mechanism of mercury toxicity occurred through first order, or pseudo-first order chemical reactions. Since the basic assumptions were inaccurate, the wrong equations were used, making it difficult for reliable risk assessments to be performed.

However, in the case of elemental mercury exposures, there will be no counterbalancing effect of concurrent selenium intakes in molar excess of the mercury exposure. Therefore, the risks associated with high elemental mercury exposures will be much greater than in the case of similar methylmercury exposures from fish consumption.

The MN Pollution Control Agency and the MN Dept. of Health have done a lot of work in this area. In fact, they have a black Labrador Retriever named Clancy trained to sniff out mercury vapor that they take to schools both for demonstration and testing purposes. (They also have mercury vapor meters - I figured I best include that note as well.)

 < /o:p>

- Diane Amell, MNOSHA

 < /o:p>

Good morning, Jim--

You could try some of the schools in the Great Lakes area. This region is a little more sensitized to mercury as an environmental hazard due to the fish consumption guidelines (we do love our fish frys), and many people fish on the smaller lakes as well for recreation & dinner.

The warnings about how much fish is safe to eat for the various groups of the population are on the local news every time they are revised. The reports also usually indicate the contaminant responsible foe the guideline.

Beth

Beth Shepard / Technical Compliance Specialist
Regulatory Compliance
6000 N. Teutonia Ave. / Milwaukee, WI 53209 / USA
P: (414) 438-3850, x5471
sigma-aldrich.com

JAKSAFETY**At_Symbol_Here**AOL.COM Sent by: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU> 03/25/2011 09:16 AM Please respond to DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>

To DCHAS-L**At_Symbol_Here**LIST.UVM.EDU cc Subject Re: [DCHAS-L] Residual Mercury in Schools

Monona and colleagues,
 
I understand and appreciate your point.  I'm hoping that with nearly 15,000 schools in the country that we'll find a couple with the "fortitude" to have a look and see if this is or is not a reasonable concern.  If NYC is not interested, we'll try Boston.  ... Jim
 
James A. Kaufman, Ph.D.
Chair, ICASE Committee on Safety in Science Education
International Council for Associations of Science Education
www.icaseonline.net

President/CEO

The Laboratory Safety Institute (LSI)
A Nonprofit International Organization for
Safety in Science and Science Education

192 Worcester Road, Natick, MA 01760-2252
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jim**At_Symbol_Here**labsafetyinstitute.org www.labsafetyinstitute.org
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In a message dated 3/25/2011 12:15:59 A.M. Eastern Daylight Time, LISTSERV**At_Symbol_Here**list.uvm.edu writes:
Jim,

The schools are already in a bind due to the finding of excessive levels of PCBs in the air from light ballasts, caulks, and other PCB-containing building materials.  Mayor Bloomberg is concerned about the expense of replacing the light ballasts when he already says they will have to lay off a few thousand teachers.

I think if you mentioned testing for residual airborne mercury to school administrators, they'd reach for the Valium and pitch your letter in the round file.

Monona

In a message dated 3/24/2011 11:55:00 AM Eastern Daylight Time, JAKSAFETY**At_Symbol_Here**AOL.COM writes:

The Laboratory Safety Institute (LSI) is considering a project to evaluate the presence of residual amounts of mercury in middle, junior, and senior high schools.
 
If there are any schools in the New York City area which would like to participate, please contact me to discuss the project. ... Jim

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