  A first comprehensive study is presented on radioactivity concentrations and
dose rates in 87 commonly used materials, manufactured or imported in Cyprus,
for building purposes. The natural radioactivity of K-40, Th-232, U-238 and
Ra-226 is determined using high-resolution gamma ray spectroscopy. The
respective dose rates and the associated radiological effect indices are also
calculated. A comparison of the measured specific activity values with the
corresponding world average values shows that most of them are below the world
average activity values. The annual indoor effective dose rates received by an
individual from three measured imported granites and four measured imported
ceramics are found to be higher than the world upper limit value of 1 mSv y-1.
Hence, these materials should have a restricted use according to their
corresponding calculated activity concentration index values and the related EC
1999 guidelines.
