Why does LEED promote putting FlyAsh with high mercury content into landfills, where it may contaminate groundwater, and NOT into Concrete, where it is non biologically available? As we clean the air by putting more mercury into the flyash, and this problem will become more prevalent.
LEED should encourage flyash with higher mercury be put into concrete so that less mercury can possibly leach into groundwater from landfills.
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Susan Walter
HDRLEEDuser Expert
1296 thumbs up
July 2, 2013 - 12:09 pm
Okay, I'll play. You install concrete with high mercury fly ash and you put in as much of this mercury laden fly ash in as your structural engineer allows (in other words extreme amounts of mercury in your fly ash). The mercury is kept in 'statsis' by the concrete and the occupants happily walk all over it. Then they decide to remodel and now they are saw cutting and drilling new holes through this concrete. The dust now contains mercury which is now air borne and it will find its way into the building some how (shoes, clothes, etc). So now we have mercury in the air systems of a hospital. Now imagine that it is your very ill loved one who is exposed to this dirty air.
This is the only scenario I can imagine that is behind this ban. But there are environmental impacts of not doing something with the mercury contaminated fly ash as you point out. I do not recall if this mercury fly ash ban is in LEED v4 for all LEED programs or if it is specific to healthcare.
Interestingly, synthetic gypsum board is the by-product of coal plant smoke stacks cleaning required by the Clean Air Act and contains impurities like mercury and other compounds. My guess is the committee thought SCMs were a good place to start on moving the marketplace.
brian lutey
VP of Green Buildingozinga rmc
18 thumbs up
July 2, 2013 - 12:38 pm
Lets have some real fun. So we might ingest some concrete dust left behind after a remodel, and to avoid this we risk polluting groundwater tables across the country? The flyash with say 500 ppb, which is now chemically part of the concrete, is normally only 2% of the hardened concrete, for a mercury content of 10 ppb. This is 1/100th of the maximum safe level for fish tha we eat on a regular basis. (1 ppm = 1000 ppb)
Re Mercury; Its safer to eat concrete dust than tuna. Do hospitals serve Tuna? Should there be a LEED credit for removing tuna from the menu?
We need to use real science when setting these standards, and balance the pro's and con's, including the unintended conscequences.
Susan Walter
HDRLEEDuser Expert
1296 thumbs up
July 26, 2013 - 1:49 pm
Brian,
Sorry for the delay - combination of vacation and not going back into on this thread until Catherine posted.
There is a real push in the healthcare world to eliminate the use of mercury based on the MOU from the EPA and I do know systems that have taken it to the point of looking at tuna suppliers. Since LEED isn't about food, it shouldn't be in LEED. (Health systems have other programs to use like HHI and Healthy Food programs.)
Here's a good paper on the effects of mercury on human health: http://66.39.146.92/pdf/hyman_at.pdf. It is a summary of various aspects of mercury on humans including dental amalgams to methyl mercury. Mercury is a compound that stays in your body so that even small amounts of exposure have a cumulative effect over your life.
The FDA sets a limit of 1 ppm and the EPA sets a drinking water limit of 2 ppm for mercury.
brian lutey
VP of Green Buildingozinga rmc
18 thumbs up
July 26, 2013 - 3:27 pm
I understand the effects that Mercury can have on the human body, which is why it should be encouragedto lock it chemically inside concrete, where it is not available to get into the air, water, or people, even after the structure is demolished. There is NO fly ash in the USA available for use in concrete, that meets the 5.5 ppm limit in LEED for healthcare. The result is that the flyash and the mercury within it, will be sent to a landfill where it may eventually end up in the ground water. Every ton of ash in concrete reduces the CO2 of that concrete mix by a tonas well, so there is additional unintended consequences of an unrealistic fear of a bad substance like mercury. Mercury is a very bad actor when it is in living beings. The best way to make it not biologically avialable for any linving being is to lock it up in concrete. Lock up the bad material for good in concrete, don't ban it.
brian lutey
VP of Green Buildingozinga rmc
18 thumbs up
July 26, 2013 - 3:39 pm
Examples of average mercury levels in other materials you may come in contact with on a daily basis: Limestone, 12 ppb; Clay 52 ppb; iron ore 78 ppb; silica (sand, Diatomacious earth, sandstone, blasting grit) 95 ppb; Wood ash, soil, lime 42 ppb