USE OF CHEAPER BRICKS - HEALTH CONCERNS

Construction cost of buildings is increasing by the day. Everybody is familiar with the “red bricks”, which are seen stacked up in any construction site. It is estimated that the cost of construction of a brick wall has gone up from about 500 rupees a square meter in 2003 to over a thousand rupees in 2007!

Cheaper alternatives suggested are: 1) bricks made up of “fly ash”, a waste product from coal-based thermal power plants and 2) gypsum load-bearing panels. The fly ash contains the natural radionuclides which are present in the coal and get concentrated in the fly-ash while burning. Gypsum salt (Phospho-gypsum), obtained as a waste product of the phosphoric acid production process, generally contains significant amount of naturally occurring radioactivity, mainly uranium and its decay products. The radionuclides of concern are: Uranium-238, Radium-226, Thorium-232 and naturally occurring K-40. A few hundreds of Becquerel (unit to express the quantity of radioactivity) of the activity per kg of the materials are likely to be present.

The storage areas of such materials or the houses made by using bricks made out of such materials are potential sites of radioactive radon (Rn-222) gas (decay product of Ra-226) inhalation hazard. From radiation protection considerations, it is suggested that before such materials are used for commercial exploitation, an assessment of the materials is made for their radioactive content. If necessary, the material should be processed to remove the radioactivity content as much as possible. Clearance from the appropriate authorities may be required before large scale use of the “waste” materials.