Determination the concentration of radon in human urine using LR-115 detector

Abstract


Introduction
Radiation and radiation emitters (radionuclides) can expose the whole body (direct exposure) or expose tissue inside the body when inhaled or ingested. Different types of radiation vary in their ability to damage different kinds of tissue. All kinds of ionizing radiation can cause cancer and other effects. The main difference in the ability of alpha particles, beta particles, gamma-rays and x-rays to cause health effects is the amount of energy they have, their energy determines how far they can penetrate into tissue, it also determines how much energy they are able to transmit directly or indirectly to tissues and the resulting damage [1]. The biological damage resulting from a given absorbed energy may be quite different for different tissues for these reasons, it is necessary to measure the radiation with an instrument and then translate it into response of tissue. Since different detectors do not have the same efficiency or sensitivity for all types of radiation and at all energies, there is no single instrument that can be used for alpha, beta and gamma [2].
The monitoring of trace metals in human urine plays an important role to gain a better understanding of sources of environmental contamination. However, human urine is a complex matrix containing high levels of urea, uric acid, proteins, fats, sodium, potassium, bicarbonate and chloride [3].

Collection of the samples
Twenty samples of human urine were taken from the hospital to measure the concentration of radon gas that emission from urine human, these samples are shown in Table 1.

Experimental details
The human urine samples were collected about 0.1 litter and stored for one month at normal laboratory conditions which were kept in plastic containers. This time is necessary to get a radiological equilibrating to the samples, before determining the concentration of natural radioactive material for the sample. Sheets of LR-115 were cut into small pieces each one of (1×1cm 2 ) area, then we put the track detector LR-115 into inner cover side of cylindrical container for two months to registries α-particles tracks that emitted from radon gas as shown in Fig1 where τ is the mean life of radon and equal to (5.5 days). In this study the actual exposure time (t) is 60 days and the effective exposure time is: T eff = 56.5 days. It is clear that the effective radium content of the sample can be calculated from the flowing formula: [7,8]  h: the distance between the detector and the top of the sample and equal to (0.17 m). V: the volume of the sample in liter and in this study equal to (0.1 liter). All of these procedures were completed at normal condition without using heating or cooling. To determine the concentration of radon we used the Eq.(1). The radon concentration in all samples (Bq.l -1 ) are shown in Table 2 and Fig.3.  The radon concentration in male urine samples are shown in Table 3 and Fig.4.

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The radon concentration in female urine samples are shown in Table 4 and Fig.5.  The radon concentrations in urine human of Baghdad samples are shown in Table 5.
The radon concentrations in urine human for Basrah samples are shown in Table 6.  The radon concentrations in urine human for Ramadi samples are shown in Table 7. The radon concentrations   in urine human  for  Baghdad,  Basrah and Ramadi samples are shown in Fig.7.

Discussion
From Table 2, the radon concentration in all urine human samples vary from 2.12×10 -3 Bq.l -1 to 4.42×10 -3 Bq.l -1 , the minimum of radon concentration was in the sample U14-(female, 30year, housewife, Baghdad) and the maximum of radon concentration was in the sample U3-(male, 45year, worker, Basrah). From Table 3, the radon concentration of urine human in male samples that vary from 2.43×10 -3 Bq.l -1 to 4.42×10 -3 Bq.l -1 , with the average of 3.21×10 -3 Bq.l -1 . The minimum of radon concentration of urine human in sample U6-(meal, 22 year, farmer, Baghdad) and the maximum of radon concentration of urine human was in sample U5-(male, 20year, worker, Basrah). From Table 4, the radon concentration of urine human in female samples that vary from 2.12×10 -3 Bq.l -1 to 3.78×10 -3 Bq.l -1 , with the average of 2.89×10 -3 Bq.l -1 The minimum of radon concentration of urine human in female was in sample U14-(female, 30years, housewife, Baghdad), the maximum of radon concentration of urine human in female was in sample U16-(female, 35 years, worker, Basrah). From Table 3 and Table 4, we note that there is a difference of radon concentration in urine human between male and female samples because the radon concentration in urine human increased when the human is exposed for a long time to the radiation. From Table 5 the radon concentrations of urine human in human samples where lived in Baghdad were varied from 2.12×10 -3 Bq.l -1 to 3.66×10 -3 Bq.l -1 , with the average of 2.66×10 -3 Bq.l -1 . The minimum of radon concentration of urine human was in sample U14-(female, 30years, housewife, Baghdad) and the maximum of radon concentration of urine human was in sample U4-(male, 65years, pensioned military man, Baghdad). From Table 6, the radon concentrations of urine human in human samples where lived in Basrah were varied from 3.30×10 -3 Bq.l -1 to 4.42×10 -3 Bq.l -1 , with the average of 3.71×10 -3 Bq.l -1 . The minimum of radon concentration of urine human was in sample U5-(male, 20years, worker, Basrah) and the maximum of radon concentration of urine human was (4.42×10 -3 Bq.l -1 ) in sample U3-(male, 45years, worker, Basrah). From Table 7, the radon concentrations of urine human in human samples where lived in Ramadi were varied from 2.87×10 -3 Bq.l -1 to 3.15×10 -3 Bq.l -1 , with the average of 3.01×10 -3 Bq.l -1 . The minimum of radon concentration in human's urine was in sample U18-(female, 29years, housewife) and the maximum of radon concentration of urine human was in sample U12-(worker, 29 years, housewife). From Tables 5, 6 and 7, the average of radon concentration in humans urine from Baghdad samples is less than the radon concentration in human urine from Basrah samples because the radioactivity in Baghdad less than Basrah and the average of radon concentration of urine human from Ramadi samples were between them because most areas of Ramadi contents a phosphate in soils and rocks.

Conclusions
From all the previous tables and results, the values of radon concentrations of urine human was dependence of the person's occupation, years of service, sex, age and health condition have been dealt with in sufficient details as required. All these results are low compared with the allowed limit 12.3×10 -3 Bq.l -1 [9].