natural radioactivity
3.This paper reports the investigation results of natural radioactivity level in riv-er,lake,reservoir,spring,tap water and offshore water in Guangdong Province(includeHainan province).
4.RELATIONSHIP BETWEEN RADIOACTIVITY OF NATURAL GAMMA RAY FROM ROCKS AND LITHOLOGY IN DAQING OIL FIELD
5.After the examination, the sandstone is zero radioactivity, non-toxic， tasteless, no pollution ，sound-absorbing, moisture-absorbing, moistureproof, slip resistance , light-absorbing and so on,it is a natural environmental protection stone material which the marble and the granite incomparable.
