Should We Move to Escape Water Radiation?
October 8, 2013 12:37 PM   Subscribe

We rent a house in a subdivision with its own (well-based) water supply, which isn't that uncommon where we are. But apparently there is radioactivity in the water supply. Details below.

Three times in the last year, we've received a notification that says:

The Texas Commission on Environmental Quality (TCEQ) has notified the [subdivision name] Corporation water system that the drinking water being supplied to customers had exceeded the Maximum Contaminant Level (MCL) for GROSS ALPHA PARTICLE ACTIVITY. The U.S. Environmental Protection Agency (U.S. EPA) has established the MCL for GROSS ALPHA PARTICLE ACTIVITY at 15 pico curies per liter (pCi/L), and has determined that it is a health concern at levels above the MCL. Analysis of drinking water in your community for GROSS ALPHA PARTICLE ACTIVITY indicated a level of 18 pCi/L.

This is not an emergency. Certain minerals are radioactive and may emit a form of radiation known as alpha radiation. Some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting cancer.

You do not need to use an alternative water supply. However, if you have health concerns, you may want to talk to your doctor to get more information about how this may affect you.

We are working to correct the problem.

At this time we are in the preparatory stages of a pilot test.

3rd & 4th qtr of 2009, running avg 16pCi/L
1st & 2nd qtr of 2010, running avg 16pCi/L
1st qt 2013 Gross Alpha, running avg 18pCi/L
1st qt 2013 Comb. Radium(-226 & -228) 6pCi/L

We spoke with our landlady and she has told us the "pilot test" could take six months, then another year before installing any kind of filtration is approved. She told us not to worry, it wasn't dangerous especially if you mostly drank bottled water.

Of course, Google tells us that showering makes you inhale atomized water, which increases your risk of lung cancer if it has radioactive particles in it. And of course we wash clothes and dishes in this water.

We have an open-ended lease and could move any time (once we scraped together a deposit) but we kind of like this house and moving is a hassle.

How worried should we be? We've been here about a year and three months.
posted by emjaybee to Health & Fitness (14 answers total)
The maximum level is 15 pCi and your water is 18? I wouldn't be worried about that at all. They're always super cautious about setting those limits.

Radiation isn't a big deal at low levels. You get a lot of radioactivity from natural sources - from the sun (especially while flying), minerals in the soil, lots of foods that take up those minerals, etc. For example, wikipedia tells me that a single banana contains 15 Bq of radiation, which works out to 4x 10^-10 Ci, or 400 pCi if I can math right today. Way more than the 18 pCi found in a whole litre of your water.

Google will tell you everything on the planet will kill you, unfortunately.
posted by randomnity at 1:13 PM on October 8, 2013 [2 favorites]

Radionuclide - Maximum Contaminant Level (MCL) Allowed by EPA
combined radium 226/228 - 5 pCi/L
gross alpha standard - 15 pCi/L
Not very. It's barely over the limit. Besides...
The National Inorganics and Radionuclide Survey(NIRS), performed by the EPA, found large numbers of water treatment plants in the midwestern and southeastern states processing water with radium concentrations in excess of EPA's Maximum Contaminant Levels (MCLs).
Scheme water and water elsewhere may not be as safe as the water you currently have.

What's the worry in scale? The Potassium-40 in soil is usually good for about 11 pCi/g. Obviously you don't go inhaling multiple pounds of soil but the radiation is next to nothing in the grand scheme of things.
posted by Talez at 1:15 PM on October 8, 2013

xkcd's radiation dose chart may be reassuring?
posted by kmennie at 1:19 PM on October 8, 2013 [3 favorites]

Not all MCLs are super-protective, because factors like cost of treatment are considered. IANYRA (I am not your risk assessor), but very quickly eyeballing the risk with a drinking water radiation expert, we wouldn't move if we were you.

The quick and dirty evaluation showed that the only exposure that was at all unacceptable was ingestion - ie, her model suggested that showering and bathing (with conservative models) with those levels was a low risk. That said, she wanted to look more closely at the numbers tomorrow to be sure she wasn't overstating things, and I'll get back to you if that changes.

To better understand how cancer risk is evaluated and presented, you might google the concept of excess lifetime cancer risk. EPA and other protection agencies evaluate risk by how many more cancers would be expected in a population with that exposure. Usually an ELCR of 1 in a 100,000 (sometimes one in a million) risk is considered "safe".

Her quick evaluation showed that drinking that water for a lifetime would pose a higher risk than that (somewhere in the 1 in 10,000 range, if I recall correctly), and so I, personally, would avoid drinking the water for now, even knowing I wouldn't be drinking 2 liters a day for 70 years like the models use. But I would shower, bathe, and wash with that water.

Your TCEQ may also have someone who can walk through this data with you, if you call saying you have a question about radiation in your water.
posted by ldthomps at 1:25 PM on October 8, 2013 [2 favorites]

If memory serves, Alpha particles are practically harmless if you don't ingest them. They can't get through even the dead layers of skin. The only problem is ingesting them, since mucus membranes don't have a protective layer.

So don't drink or cook with it, and it should be fine.
posted by gjc at 1:45 PM on October 8, 2013

The EPA says:
The radon in your water supply poses an inhalation risk and a small ingestion risk. Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes. Research has shown that your risk of lung cancer from breathing radon in air is much larger than your risk of stomach cancer from swallowing water with radon in it.
So it's not terribly unsafe to drink, but taking showers in it may be bad (as your Googling suggested). How about that for counterintuitive?

Personally I'd just shrug and live with it.
posted by pipeski at 2:21 PM on October 8, 2013

Do you know what the source mineral is? You can buy shower filters that you simply screw between the showerhead and the wall ($40ish for a cheap one). Depending on the mineral and on the filter, you may be able to install something yourself as a basic stopgap/reduction measure in the meantime while they sort out proper filtration at the supply.
posted by anonymisc at 2:25 PM on October 8, 2013

I would be more concerned about radon in the air in your house, which could be getting released into your foundation from the same subsoil strata where your water comes from. If you have not done a radon test, I suggest you do one. Buy a kit at the hardware store or big orange box store.
posted by beagle at 2:34 PM on October 8, 2013 [1 favorite]

Seeing some of the other speculative answers, I finally understand the doctors and lawyers who urge OPs to talk to a professional. Talk to the CEQ about your results if you have questions. Your levels aren't very high, but the USEPA MCLG (goal) for radionuclides is zero, because there's no "healthy" level of radiation exposure over zero. The MCLs are set at higher levels because many areas of the country have naturally occurring radiation, and the cost/benefit for treating low levels of radiation is expensive.

I see from googling that Texas had a scandal awhile back about radionuclide results in drinking water (underestimating levels because of costs / differing risk assessment methods), so there are likely experts at the CEQ who thoroughly understand radionuclide risk and have been trained to communicate that to the public. They likely have spreadsheets like the one I borrowed that will calculate the risk for your levels of those specific radionuclides.

Just fyi, when running the numbers to come up with my conclusions above, I used 3 pCi/L each of -226 and -228. A risk assessor may ask if you have those individual results (instead of combined) when discussing your risk. Again, the answer to "how worried should I be?" is probably not very, especially for non-drinking uses. But the best people to answer that are the professionals at your CEQ.
posted by ldthomps at 3:06 PM on October 8, 2013 [3 favorites]

There are published tables that the EPA uses to calculate the relative risk of exposure to radioactive nuclides, available here. I agree that you should believe the opinion of a professional over any back-of-the-envelope calculation, but if you have an inclination to see the underlying data, this is a decent place to start. For what it's worth, I get about the same order of magnitude as ldthomps using the EPA data and assuming 16 pCi/L and 1L/day for 100 years, but I mention this only to illustrate that this can be roughly estimated by hand, not to indicate that you should believe me or that the professionals need to be double-checked.

I will note though that the reading of 18 pCi/L means that your increased risk above the level at which they would not be required to notify you (and thus the level you could be ingesting anywhere else if you chose to move) is basically 20%, so if the maximum risk in the non-notified case is up to 1:100,000 or whatever, the increased risk is now 1.2:100,000. If you wanted to realistically assess what you would gain by moving or drinking from an alternative water source, you can't assume that the alternative is going to have 0.000 pCi/L.
posted by kiltedtaco at 6:10 PM on October 8, 2013 [1 favorite]

Alpha radiation doesn't cause cancer. It's strong beta and gamma radiation that does.
posted by KRS at 7:26 PM on October 8, 2013

Alpha radiation doesn't cause cancer. It's strong beta and gamma radiation that does.

I've been a radiation worker in one form or another for nearly a decade (including at the facility mentioned as a source in the XKCD chart above), and unfortunately, this just isn't true. Due to their comparatively enormous mass and their electrical charge, alphas interact strongly with other matter, depositing their energy within a very short distance, and thus don't tend to travel far into tissue, if at all--they can generally assumed to have been stopped by the dead skin layer on the outside of your body or the water layer on your cornea. However, this vanishes as a benefit when the alpha-emitting substance is internalized: the strong interaction/damage now happens, not harmlessly in your protective outer coatings, but in the nearby layers of your internal organs.

(on preview, what gjc said)

This can possibly damaging; it might be one of the reasons why smoking can cause lung cancer, for instance. (Here's another article in which the possible cancer-causing effects of radiation are difficult to identify against the effects of other health risks, like, again, smoking.)

That being said, that's a clinical, textbook radiation-explanation, not a medical opinion. As pointed out the legal limits are set to incredibly small levels--way lower than any level that could be calculated to cause any sort of harm--for your protection. It's great that your community recognizes the natural environmental impacts and actually tests for these things. It's possible you've lived (or would then move to) other places which were worse and just didn't know it, right? At least here you know it's being monitored. There are a *lot* of sources of environmental radiation (for instance, the bananas listed above) and they aren't really bad. You've got to keep this incredibly minor risk factor in context of all the other risk factors in your life, most of which are probably less well-studied and protected against than this one. Your body is also incredibly good at repairing itself, which it does constantly.

To answer your question more directly: I don't think you need to be worried at all. It's understandable that you might feel so, anyway, and you could ask your governing agency for ways to reduce risk. As beagle said, you might look into a radon detector, a good investment for anyone with a basement/in an area with high concentrations of certain minerals in the soil.
posted by spelunkingplato at 1:17 AM on October 9, 2013 [1 favorite]

Metafilter is the best, you guys. Really. This is all great information, thank you so much. I think we will move eventually for unrelated reasons, but it's good not to have to hurry about it.
posted by emjaybee at 8:14 AM on October 9, 2013

If the radioactive substances are mineral-based, then could you remove them with an ordinary water-softening system?
posted by Sunburnt at 8:31 AM on October 9, 2013

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