Study On The Method Of Soil Radon Exhalation Rate In The Laboratory And The Correlation With Soil Properties

It attracts more and more attention on the radon’s hazard to human. The negative effect of indoor radon concentration on human health has become the world’s hot issue. Soil Radon is a major source of indoor radon in the natural radiation level surveys, particularly in the level of monitoring indoor radon. So soil radon exhalation rate has become an important evaluation index. There are many factors that affect radon exhalation rate, among which soil properties is an important one. Therefore, it is significant to study of soil properties’ effect on radon exhalation rate during environmental assessment.The laboratory measurement method of radon exhalation in soil samples was designed in this paper based on the character of radon and exhalation mechanism in this paper, excluding the effect of environment factor such as rain, air pressure, earth temperature, humidity during the measurement of on spot radon exhalation rate. It provided an effective method for studying radon exhalation of samples. Then this paper studied the relationship between soil radon exhalation rate and soil property, emphasizing on the effect of several important soil property parameters on radon exhalation rate, such as radium content of soil, water content and porosity. And the author took several typical soil samples in Beijing Area and Zhuhai Area as examples to carry out laboratory measurement of radon exhalation rate and soil property parameter measurement. According to the experiment results, the author analyzed the intrinsic relation between radon exhalation rate and soil properties.In this paper, measurements experiment of radon exhalation rate from soil in the laboratory was designed by the use of Alpha GUARD PQ2000.The device was innovatively designed and improved. After checking the sealing property and repeatability in the experiments, the results took on pretty good and it could measure the soil sample effectively. In my paper, whether in the measurement process or in the correlation analysis process, the radon exhalation rate was not subjected to the environmental factors. The radon exhalation rates of some typical soil samples both in Beijing Area and Zhuhai Area were measured by this method. Soil properties’ effect on radon exhalation rate from soil was inherent factors. The results showed that soil properties had obvious influence on the radon exhalation rate.Among them, the radium content had positive correlation to soil radon exhalation rate and the correlation coefficient was about 0.559. In the condition that the water content was below 30%, radon exhalation rate from soil increased with the increasement of water content. Porosity had weak correlation with radon exhalation. It could be seen that radium content of soil had larger effect on radon exhalation rate than other two parameters.