In Malaysia, the sources of water depend on rainfall, which
ranged from 2000 to 2500mmon average annually. Most of the
supply of water originates from streams and rivers in the
country, while the contribution of ground water is 1% of the
required water (Azrina, Khoo, Idris, Amin, & Razman, 2011).
High concentration of radon and heavy metals in tap, river
and well water used for drinking may pose adverse side effects.
In this study, measurement of radon and toxic elements
in water of Sungai Petani, Kedah, Malaysia was carried out to
assess the non-carcinogenic and carcinogenic health risks for
the population exposed to radon and toxic elements. Sungai
Petani is a capital of district Kala Muda in the state of Kedah,
situated in the north parts of Peninsular Malaysia and covers
an area of 925 km2 (Noresah & Ruslan, 2009). Fig. 1 shows the
location of the study area.