Waste containing Naturally Occurring Radioactive Material
(NORM) is generated in industries which handle uranium and thorium containing raw
materials. The waste contains radioactive uranium/thorium and their progeny and
or K-40 which are naturally present in the earth crust in rocks, in ores/minerals
and in coal. After recovery of the useful product elements, the waste contains
traces of radioactive elements and can pose an environmental hazard. The fly-ash
(waste product after burning of coal) also contains radionuclides in more
concentrated levels as compared to their presence in coal. The ash waste is used to
make bricks in some countries. The constraint is the emanation of radioactive radon gas from
the traces of Ra-226/224 present in the fly ash.
There are regulatory limits on the radioactivity
elemental concentration levels for disposal without any controls. However, in
most of the industrial situations the activity concentration levels are much
higher and are not safe to indiscriminate disposal in the environment. Disposal
as road fillings is one of the uses of NORM waste.
It is time that national regulatory bodies wake up
this public health concern and enforce appropriate controls on the disposal of
the NORM waste.
