18 September 2009

Granite counters have been proved to be safe. Again.



Toward the end of July 2008, The New York Times ran an article in its Home and Garden section about the supposed dangers posed by radioactive granite counters. Their piece was prompted by a concerted effort by an industry group that represents solid surface fabricators to prop up their dying product category by any means they could. So they took a bunch of information about normal, background radiation; dropped all context and pretense of real science, and embarked on campaign of fear-mongering and misinformation. Their efforts found fertile soil at the Home and Garden desk at The Times and so a public health threat was born. Never mind that wasn't a threat to begin with.

The Times story grew legs and fast. Within days I was fielding calls from people who were flipping out over the imaginary dangers lurking in their kitchens and bathrooms. I wrote about it a lot in the last year or so. I knew the whole thing was BS and wasted no time saying so. If you're interested in what I've had to say about this, click here, here, here, here, here, here, and here.


So rather than prattle on even more about it, here's an excerpt from Professional Remodeler:

Two new studies published in the scientifically peer-reviewed Journal of Exposure Science and Environmental Epidemiology show that granite used in countertops poses no radon or radiation threat to consumers.

"Based on the results of our research, we did not identify any slabs of granite intended for sale as countertop that would produce exposures that exceed health-protective limits or background levels commonly found in the environment," said Dr. Joseph G. Allen, of Environmental Health & Engineering, Inc., a principal investigator in both studies.

The science behind the studies was rigorously reviewed by independent scientists at the request of the Journal to ensure the studies are valid and used appropriate scientific methodology. Statements made by critics of granite countertops have not undergone this peer-review process.
The studies, published in the August 26, 2009 online issue of the Journal, conclude:

  • The market share-weighted average concentration of radon in indoor air attributable to emissions from granite countertops was estimated to be about 400 times lower than the action level recommended by the EPA.
  • Typical granite stones are likely to be a minor source of radiation dose when used as a countertop material within the home and present a negligible risk to human health.
  • Critics of granite have suggested that granite countertops pose significant health risks. However, after a year of claiming to have scientific proof, no study has been published by a scientific, peer-reviewed journal that demonstrates a meaningful environmental exposure resulting from granite countertops.
And here's the abstract from the actual, published paper from an actual, peer-reviewed scientific journal.
Humans are continuously exposed to low levels of ionizing radiation. Known sources include radon, soil, cosmic rays, medical treatment, food, and building products such as gypsum board and concrete. Little information exists about radiation emissions and associated doses from natural stone finish materials such as granite countertops in homes. To address this knowledge gap, gross radioactivity, γ ray activity, and dose rate were determined for slabs of granite marketed for use as countertops. Annual effective radiation doses were estimated from measured dose rates and human activity patterns while accounting for the geometry of granite countertops in a model kitchen. Gross radioactivity,  activity, and dose rate varied significantly among and within slabs of granite with ranges for median levels at the slab surface of ND to 3000 cpm, ND to 98,000 cpm, and ND to 1.5E-4 mSv/h, respectively. The maximum activity concentrations of the 40K, 232Th, and 226Ra series were 2715, 231, and 450 Bq/kg, respectively. The estimated annual radiation dose from spending 4 h/day in a hypothetical kitchen ranged from 0.005 to 0.18 mSv/a depending on the type of granite. In summary, our results show that the types of granite characterized in this study contain varying levels of radioactive isotopes and that their observed emissions are consistent with those reported in the scientific literature. We also conclude from our analyses that these emissions are likely to be a minor source of external radiation dose when used as countertop material within the home and present a negligible risk to human health. [italics mine]
I'm waiting for the rest of the mainstream media to pick this up but I'm not holding my breath.

3 comments:

  1. I've always wondered why there was never any mention of older buildings such as banks that have granite floors, granite columns, and granite countertops. Nothing more than shameful scare tactics.

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  2. The radiation scare tactics remind me of the bacteria scare tactics that are being bandied about currently. The press and other irresponsible people take a possible concern and whip it into doomsday sequence.

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  3. Thanks Ann, shameful's the right word. The kinds of twisted scare mongering the the trade group in question engaged in at the time has since passed into the realm of conventional wisdom and I find it enraging. They know words like "radioactive" are guaranteed to get an emotional reaction and they exploit that fear. It distracts people from real threats and dangers and it builds a marketing message around an outright lie. It's incredibly short sighted and it harms far more people than it helps.

    Because of these lies, I have to spend more time educating people than I should have to and I end up defending granite as a counter material, and I don't particularly like shiny granite!

    David, I am dying to see your biologists' take on that study from yesterday.

    ReplyDelete

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