RadioactivityHeavy metals a b s t r a c t Assessment of naturally occurring radionuclides and heavy metals in 5 major dumpsites around Lagos and Ogun State, Nigeria, was carried-out to determine the natural radionuclide and heavy metals in the dumpsites and to evaluate the hazards these may have on the public. Radionuclide concentrations were determined using gamma-ray spectrometry with NaI (Tl) detector. The mean activity concentrations of 226 Ra, 232 Th and 40 K in the soil samples were 23.840.9 ± 42.0 in Ogijo, respectively. The results of 226 Ra and 232 Th are lower than the world average but higher for 40 K (UNSCEAR, 2000). The analysis of the heavy metal concentrations indicated that there is presence of Cadmium, Zinc and Copper in high proportion. These metals are toxic and may cause severe problem with prolonged exposure. Monitoring the accumulation of these metals in soil samples is very important and the practice of cultivating the land for planting vegetables and legumes by farmers around the dumpsites must be discouraged to prevent the transportation of these toxic metals into human system.

Background: The problem of radon (Radon-222) in water is one of the daily health hazards faced by those in Ojo Axis, Nigeria. Therefore, continuous monitoring of radon contamination in different types of water is essential. In the present work, sixteen groundwater and surface-water samples (wells, boreholes, and sachets) were collected from six different locations within the Ojo Local Government area in Nigeria. The water samples collected were stored in 75 cl bottles that were already sterilized with distilled water to avoid contamination. Water samples were then taken to the laboratory for the analysis of radon levels using a RAD7, an active electronic device produced by the Durridge Company in the USA. The radon level in the water is higher than the safe limits of 11.1 Bq/L, as per EPA regulations, except for two sample points from the studied areas. The total annual effective doses from ingestion and inhalation for drinking and groundwater were higher than the safe limit of 0.1 mSv y−1 that is recommended by the World Health Organization and the European Union Commission. Conclusions: The obtained results underline the importance of the development and/or updating of databases regarding radon levels in drinking and groundwater in the Ojo Local Government area in Nigeria.

Background Radon (Radon-222) in water is one of the daily health hazard problems. Therefore, continue check of radon contamination in different types of water is essential.in the present work, sixteen groundwater and surface-water samples (wells, boreholes, and sachets) were collected from six different locations within Ojo Local Government area in Nigeria. The water samples collected were stored in 75 cl bottles which were already sterilized with distilled water to avoid contamination. Water samples were then taken to the laboratory for analysis of radon using RAD-7, an active electronic device produced by the Durridge Company in the USA. Results The radon level in water is higher than the safer limits of 11 Bq/l as per EPA regulations except one site of the six under study. The total annual effective doses from ingestion and inhalation for drinking and ground water is upper than the safe limit of 0.1mSv y− 1 recommended by WHO and EU council. Conclusions The obtained results promote the development and/or the update of databases of radon levels in drinking and ground water in Ojo Local Government area in Nigeria.

Dumpsites in Nigeria are generally open and significantly elevate the pollution and contamination level of the total environment.  Indoor radon was measured with CR-39 detectors in some buildings in the vicinity of dumpsites in Lagos, Nigeria. Eight (8) dumpsites (4 dormant and 4 active dumpsites) were chosen for this study. Detectors were exposed in 50 houses randomly selected within 0 and 100m away from the dumpsites. The detectors were exposed for 3 months. They were then retrieved and etched in a 6M NaOH solution in a water-bath at a temperature of 90o C for 3 hours. Tracks were counted using a semi-automatic system with a DCE camera mounted on a microscope and connected to a PC. Radon concentration ranged from 24.00±4.86 to 656.00±131.20 Bqm-3 in the active dumpsites.Mean concentrations were 120.3±24.0, 257±51.4, 179.8±33.6, and 131.5±19.4, respectively in Oke-Odo, MRF, Olusosun, and Solus-3. In the dormant sites, concentration ranged from 16±3.2 to 931±186.3 Bqm-3 having means of 194.17±38.80, 206.75±41.33, 223.25±44.69, and 334±66.85Bqm-3 , respectively in Oke-Afa, Solus-1, Solus-2, and Solus-4. The annual effective dose and cancer risk in the active and dormant dumpsites were (3.60 mSv, 8.97 per million person-yearly) and (4.53 mSv, 12.47 per million person-yearly), respectively. This study revealed some high value of radon concentrations in some houses close to the dormant dumpsites than in the active dumpsites. This is unsafe and can cause severe health issues in the long term. Keywords: Radon, dumpsites, Olusosun, CR-39, buildings, Lagos state, SOLUS

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