December 29, 2016

Radon: a ‘natural’ environmental hazard

Back in the olden days, houses were constructed with hefty foundations and in areas where airflow was required, high stilts (eg. The Queenslander style) formed an airy, high and usable cavity where fresh breezes circulated. Old-fashioned idea, but now, it is being seen as a very practical design not just in Australia but all over the world.

The concrete slab house is something fairly recent being an adaptation from industrial and commercial construction.  Concrete pre-fab walls also followed.

But are these simple methods of building better?

My uncle, a Queensland builder, swore by high brick construction with an ant-resistant hardwood-framed and timber clad house and, as a child, I remember the lessons he taught us about keeping air circulation high in the footings and foundations.  He wasn’t keen on that cellar-musty-earthy smell and warned us never to buy a house with that smell.  He said it was radon, and now I have checked out that gas, that could be quite a scary one.

It is a single-atom gas whose atoms easily penetrate foundations, concrete, paints or surface sealers, and even most plastics. Radon gas is a very powerful carcinogen and children are particularly susceptible. It is the second leading cause of lung cancer.

It is found in water, soil, concrete, stone of all kinds.

Here in Mexico, most construction is concrete walls over concrete slab and the builders are generally generous with thicknesses as the materials are inexpensive.  Problems can arise, however, if there is a breach in the slab at any point, especially where the site is on reclaimed land (much of the urban areas are either built on a deep recycled rubble base or mangroves topped with rubble and tamped).  I’ve been wondering about the safety of our concrete and what the radon problems may be. But nobody does the radon test in our town.  I’ll have to get a kit online.

Recently, news agencies reported that even granite countertops might release unsafe levels of radon. The U.S. Environmental Protection Agency explains that radon comes from the natural decay of uranium that is found in nearly all soils.  They say not to panic as it is such small levels that kitchen benches and splashbacks are not a significant factor in carcinogenic indoor radon levels. But if you are the manufacturer or decide to trim your slab, make sure you wear protective gear.

Leakage of radon from the ground through cracks in the slab (foundations) is the more worrying source.

Concrete contains earthen materials that may generate radon gas and this also set me thinking.  There is so much used in this area that I am sure that the limestone mining (source of concrete) must affect habitats of animals living in the mines areas (bats etc.).  Recycled concrete is always worth looking for and there is plenty being recycled in Australia these days.  Cement does use lots of water and needs a lot of energy for its fabrication.  However, it is the radon factor that disturbs me most as recycled or not, it will be present in the raw material.

The U.S. Army now uses something called Electro-Osmotic Pulse (EOP) technology to protect concrete basement walls in military base houses.  These seal in water, mould and gases.   An electricity-based technology eliminates the need to coat the walls with conventional waterproofing materials most of which contain harmful chemicals. Of course, the electricity can be solar or wind generated. Low-voltage direct current (DC) pulses push moisture to the outside of the wall, preventing any gas, water or mould seepage into the house.

From the USA EPA:

‘Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon can be found all over the U.S. It can get into any type of building — homes, offices, and schools — and result in a high indoor radon level. But you and your family are most likely to get your greatest exposure at home, where you spend most of your time.’

It is possible to test for radon leakage and there are kits available in the USA but in Australia, contact the EPA in your state and ask them what they are doing about it.

As it leaks in from the decayed minerals in your soil,  anything below the 2nd floor could be vulnerable.

Check the following:

  • Cracks in solid floors,
  • Construction joints,
  • Cracks in walls,
  • Gaps in suspended floor,
  • Gaps around service pipes,
  • Cavities inside walls,
  • The general water supply inside and outside.
  • Radon in water is generally at quite a high level too and washing clothes, dishes etc. can be hazardous.
  • Do a test for radon. It should only take a few minutes of your time.

The amount of radon in the air is measured in “picocuries per liter of air,” or “pCi/L.” There are many kinds of low-cost “do-it-yourself” radon test kits you can get through the mail and in hardware stores and other retail outlets. Google it!   If you are selling your house, call a building inspector and ask advice. Free Radon Test Kits are available in the USA but probably not in Australia.  When you sell, you can say that it is radon tested and this could be a selling point (provided you deal with the problem).

Radon testing of all homes once a year is advocated.  In the USA it may one day be mandatory to radon-test prior to selling.

Nevertheless, radon spas feature all over Russia and Central Europe where they are used to treat a number of conditions but apart from that and some limited scientific/medical use, there is no practical function for the gas. Perhaps ‘Radox’ was originally inspired by this.  Radon is part of nature, but we need to learn how to live with it, even the bad parts!!

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