Assessment of natural radiation in contaminated automobile workshop soils.

The presented study aims to identify and quantify the natural radionuclides activity concentrations on the top and sub-soils around mechanic workshops in Ojo and Ijegun, Lagos, Nigeria. Based on these measured radionuclides activity concentrations, radiological hazard indices are assessed. Twenty oil-contaminated soil samples were collected, and the levels of natural radionuclides activity are measured by applying gamma spectrometry The measured radionuclides with authoritative regularity are linked with the natural decay series of 238U (226Ra) and 232Th as well as the series of non-decay 40K. The obtained results show that the mean radionuclides activity concentrations in the collected oil-contaminated soils samples are 14 ± 4 Bq kg-1, 105 ± 55 Bq kg-1, and 90 ± 33 Bq kg-1, for 226Ra, 232Th, and 40K respectively. It was founded that the 226Ra radionuclide is the lower present in the oil-contaminated soils samples. The radiological assessments were evaluated in terms internal hazard index (0.54), and external hazard index (0.55) both of which are below the UNSCEAR-2000 standard limit. Consequently, the radiological assessment indicated that long-time exposure to those radionuclide's strength confuses integral hazards.

Evaluation of uranium concentration in the blood breast cancer women with CR-39 detector.

Some governorates of Iraq are considered as uranium-contaminated areas. The spread of cancerous tumors injuries was recorded in different parts of Iraq at very high rates. As cancer is closely related to high level of uranium in the blood, this study was conducted on women with breast cancer to evaluate the uranium concentrations in their blood. The aim of the study is to assess the concentration of uranium in the blood Iraqi breast cancer women to establish reference values for the levels of toxic uranium in their blood and the possibility of getting breast cancer. A total of 39 blood samples were collected from breast cancer women and a control group. CR-39 track detector has been used to evaluate the uranium concentration in blood samples by placing a drop of blood on the detectors and calculating the uranium concentrations by irradiating the detectors with a neutron source. Statistical analysis is achieved utilizing SPSS programme. The outcomes show elevated levels of uranium concentration in the blood of women with breast cancer, which was found to be 92±0.6 ngL-1 compared to the control group (40 ±0.4 ngL-1), and internationally published data. The results show that the uranium concentration in the blood of breast cancer women is higher than those in the control group and some of the globally published data. This indicated that there is a relationship between the elevated concentrations of uranium in blood and the risk of getting breast cancer.

Estimation of radon excess lung cancer near some dumpsites in, Lagos, Nigeria.

Generally, in Nigeria dumpsites are open and elevate the pollution by increasing the total environment contamination level. This affects not only the site of dumpsites but also the surrounding buildings and area. In the present work, indoor radon activity concentration is tested inside some buildings in the vicinity of dumpsites in Lagos, Nigeria. A passive technique with CR-39 detectors is used. Different buildings around different eight dumpsites were chosen. Radon concentration had ranged from 16.00 ± 3 to 931.00 ± 186 Bqm-3 in the dumpsites. With Mean concentrations range from 120 ± 24 at OKE-ODO to 334 ± 67, at Solus-4 respectively. The present results explain that 63% of the radon activity concentration in indoor air around the selected dumpsites at Lagos city in Nigeria is below the allowed limit from ICRP 200 Bq m-3 while 37% is more than this limit. Based on the measured radon concentration, the annual effective dose and cancer risk are evaluated. The range of ELC is from 242 to 14086 with mean value 3114 ± 1111.

Attachment rate characteristics of different wide used aerosol sources in indoor air.

In this work, six different aerosol sources, used in everyday life, were investigated to analyze parameters such as concentration, size distributions, and dynamics: regular and electronic cigarettes, incense, candles, mosquito coils, and cooking. During the experiments, the aerosol particle count ranged from 200 to 2·105 cm-3. The number, mass, and specific surface area of the aerosol size distributions were measured by a Model 2702 M diffusion aerosol spectrometer (DAS) with a range of 5 nm to 10 µm. The attachment rate of radon decay products to aerosol particles is calculated depending on their size distribution/ The use of household sources of aerosols (heat treatment of food, smoking, candles, etc.) result in an increase in the concentration of aerosol particles by more than an order of magnitude, mainly due to the generation of ultrafine aerosols with number median diameter 64-92 nm and GSD 1.45-1.84. The mass distribution is dominated by particles with a distribution maximum in the range of 2-5 µm. The attachment of radon decay products to aerosols is associated with ultrafine particles with diameter < 200 nm. The median diameter of the rate of attachment to aerosols is 130 nm.

Radon decay products equilibrium at different aerosol concentrations.

The influence of aerosol particle concentration on the activity of short-lived radon decay products (RPDs) was investigated inside a standard radon box. The 218Po:214Pb:214Bi activity ratio was determined for unattached and attached fractions of radon decay products at different aerosol concentrations. For the unattached fraction, this ratio was 1:0.31:0.06, while for the attached aerosol fraction the activity ratio was 1:1.4:0.91 at a low aerosol concentration (2000 cm-3) and with the unattached fraction fp = 0.45. In this case, there was no additional aerosol in the standard radon box and the equilibrium shift ratio for the total activity (attached and unattached) was 1:0.55:0.27 for 218Po:214Pb:214Bi. When the aerosol was injected, the unattached fraction nearly disappeared at a high aerosol concentration (80000-90000 cm-3). The equilibrium shift ratio for the total activity at a high aerosol concentration was 1:2:1.5 for 218Po:214Pb:214Bi. This ratio was the same for the attached fraction. For no more than 0.01 of the unattached fractions, this ratio was 1:0.85:0.7. Radioactive equilibrium factors and unattached fractions were also determined at different aerosol particles concentrations. A negative correlation between unattached fraction and the radioactive equilibrium factor, as well as a positive correlation coefficient between the radioactive equilibrium factor and aerosol particle concentration in a standard radon box, has been determined.

Comparison of radioactive aerosol size distributions (Activity, number, mass, and surface area).

Information regarding the number, mass, and specific surface area distributions of aerosols is extremely important for assessments of exposure to radiation due to the intake of radioactive aerosols by inhalation. In this study, these distributions were compared with the activity size distributions for radon decay products. The experiments were conducted in a radon chamber under controlled conditions for the aerosol concentrations and with size distributions in the range from 5 nm to 10 µm. The activity size distributions of the aerosols were measured by using a diffusion battery and two types of cascade impactors. The aerosol concentrations during the experiments were in the range from 2 × 103 to 2.5 × 105 cm-3. The measurements obtained with a diffusion battery demonstrated that at the low aerosol concentration, up to 80% of activity of the radon decay products was connected with aerosol particles with an activity median thermodynamic diameter (AMTD) ~1 nm (unattached fraction). After injecting the aerosols into the experimental chamber, the activity of the unattached fraction decreased to practically zero but we observed the presence of the activity of aerosols with AMTD values ~10-20 nm. After injecting the aerosols, the distribution of the aerosol specific surface area exhibited a bimodal distribution, where the median diameter in the accumulation mode was ~120 nm and the geometric standard deviation (GSD) was 1.3. The median diameter in the coarse mode changed with time due to the deposition of aerosols on the walls of the chamber, where it decreased from 5 µm (GSD = 1.6) at 15 min after injection to 2 µm (GSD = 2.5) at 120 min after injection. The distribution of the aerosol activity measured by the cascade impactor was virtually independent of the time from the moment when the aerosols were injected. The parameters used to assess the activity distribution comprised an activity median aerodynamic diameter (AMAD) ~500-650 nm and GSD = 1.5. Comparisons of the activity distributions with the distributions for the number, mass, and specific surface area showed that the closest correspondence was with the average distribution over the specific surface, whereas there were no exact correspondences with the other distributions.