Abstract
The back ground radiation in the natural environment is the constant companion of human beings since from their creation. Humans are continuously exposed to these radiations coming from outside and inside their bodies. Outside and inside radiations are coming from ground, building materials, food, air, the universe and even elements from human own bodies. According to UNSCEAR 2000 report, background radiations deliver an average effective dose of 2.4 mSv per person worldwide. Sustained exposure from high background radiation levels may pose substantial health threats to general public. In the current study we are presenting the results of ambient outdoor gamma dose rates measured for district Poonch of the state of Azad Kashmir. The study has been carried out by using Ludlum micrometer-19 which is an active and portable detector. Effects of geology and altitude on measured values of gamma dose rates have been investigated. Maximum and minimum values of gamma dose rates were recorded as 156 nGy.h(-1) and 65.25nGy.h(-1) respectively. The annual average dose for the whole area was estimated as 102 nGy.h(-1). Highest gamma dose rate was recorded at two places in Rawalakot and both places are the part of Quaternary Formation which is exposed to the lithology of gravels, sandstones and siltstone. Similarly the lowest individual gamma dose rate value (65.25 nGy.h(-1)) was recorded in Androat, which is situated in Siwalik Formation and exposed to the lithology of red clay, brownish gray sandstone. Current study findings shows no appreciable changes in gamma dose rates with altitudes and variations in measured gamma dose rates depends upon lithology of the area under investigation. The average gamma dose rate (102 nGy.h(-1)) measured for the current study is higher than world average gamma dose rate (57 nGy.h(-1)) as reported in UNSCEAR 2000.