Radon activity concentration measurements in water sources from Perak state Malaysia

Radon activity concentration in water samples from Perak state Malaysia and their possible health risk was assessed. The Samples were from lakes, hot springs, and rivers. The RAD7 Detector was used for in-situ measurement of radon concentration. The radon activity concentration ranged from 0.04 +/- 0.08 - 3.98 +/- 0.39 Bq l(-1), with mean of 0.69 Bq l(-1) and standard deviation of 0.92 Bq l(-1). The activity concentration ranged from 0.08 +/- 0.12 - 0.45 +/- 0.27, 0.04 +/- 0.08 - 0.62 +/- 0.32, 0.33 +/- 0.23 - 3.98 +/- 0.39 Bq l(-1), with a mean of 0.24 +/- 0.19, 0.30 +/- 0.21, 1.26 +/- 0.34 Bq l(-1) for lakes, hot springs, and rivers respectively. The result was below the UNSCEAR, USEPA and WHO action levels of 11.1 Bq l(-1) and 100 Bq l(-1) respectively. The Rn-222 contribution from water to indoor air was found to be below the recommended action level . The annual effective dose for inhalation and ingestion ranged from 0.000102 - 0.009954 mSv y(-1) and 0.000102 - 0.010112 mSv y(-1), with mean annual effective dose of 0.001733 and 0.001759 mSv y(-1) respectively. The effective doses for both inhalation and ingestion were below the world average of 0.002 mSv y(-1). The Rn-222 activity concentration in the study could be termed normal and without threat to human health.