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.

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.

Radon measurements by nuclear track detectors in dwellings in Oke-Ogun area, South-Western, Nigeria.

An indoor radon survey of a total of 77 dwellings randomly selected in 10 districts in Oke-Ogun area of Oyo state, South-western Nigeria was carried out using CR-39 detectors. The CR-39 detectors were placed in the bedrooms and living rooms and exposed for 6 months and then etched in NaOH 6.25 N solution at 90 °C for 3 h. Mean concentrations amount to 255 ± 47 and 259 ± 67 Bq m(-3) in the living rooms and bedrooms, respectively. The lowest radon concentration (77 ± 29 Bq m(-3)) was found in Igbeti, whereas the highest was found in Okeho (627 ± 125 Bq m(-3)). The annual exposure of dwellers was estimated to fall <10 mSv (6.4 and 6.5 mSv y(-1) n living rooms and bedrooms, respectively), which is the upper range of action levels recommended by the International Commission on Radiological Protection. The average excess lung cancer risk was estimated 24.8 and 25.2 per million person-years in both living rooms and bedrooms. It is believed that the high radon level in this part of the country may be attributed to its geographic location. The data presented here will serve as a baseline survey for radon concentration in dwellings in the area.

Radon measurements by nuclear track detectors in secondary schools in Oke-Ogun region, Nigeria.

Radon measurements were performed in secondary schools in the Oke-Ogun area, South-west, Nigeria, by solid state nuclear track detectors (SSNTDs). About seventy CR-39 detectors were distributed in 35 high schools of the Oke-Ogun area. The CR-39 detectors were exposed in the schools for 3 months and then etched in NaOH 6 N solution at 90 °C for 3 h. The tracks were counted manually at the microscope and the radon concentration was determined at the Radioactivity Laboratory, Department of Physics, University of Trieste, Trieste, Italy. The overall average radon concentration in the surveyed area was 45 ± 27 Bq m(-3). The results indicate no radiological health hazard. The research also focused on parameters affecting radon concentrations such as the age of the building in relation to building materials and floor number of the classrooms. The results show that radon concentrations in ground floors are higher than in upper floors.

Indoor radon survey in a university campus of Nigeria.

CR-39 tracketch detectors were used for the measurement of (222)Rn concentration in 24 offices in Nigeria's oldest university campus in order to estimate the effective dose to the occupants from (222)Rn and its progeny. The dosimetric measurements were made over a period of 3 months. Questionnaires were distributed and analyzed. The radon concentration ranged from 157 to 495 Bq/m(3), with an arithmetic mean and standard deviation of 293.3 and 79.6 Bq/ m(3), respectively. The effective dose to the workers was estimated and this varied from 0.99 to 3.12 mSv/ y, with a mean of 1.85 mSv/y. The radon concentrations were found to be within the reference levels of ICRP.