Quantification of Activity Concentrations and Radiation Hazard Indices in the Solid Minerals Exploration Fields of Benue State, Nigeria with Multivariate Statistical Approach

The quantification of activity concentrations of radionuclides and the radiation hazard indices in the exploration fields of Benue State have been carried out. Samples of the environmental matrix (soil and minerals) were collected from five mining sites of barite, limestone, lead, coal and salt in Lessle, Gboko, Anyin, Owukpa and Akuana communities. The concentrations of radioactivity was analyzed using NaI (Tl) γ-ray spectroscopy. Results showed that the concentrations of activity of the primordial radionuclides 40K, 238U, and 232Th for soil samples obtained ranged from 11.42 (Salt) – 1491.47 (Lead) Bq/kg, 12.87 (Barite) – 452.32 (Coal) Bq/kg and 6.78 (Coal)–108.41 (Barite) Bq/kg respectively. The mean value activity concentration of the radionuclides in the minerals samples at the mining sites were 10.58 – 623.36 Bq/kg, 1.97 – 540.33 Bq/kg and 2.13 – 25.28 Bq/kg for 40K, 238U, and 232Th respectively. The radium equivalent activity (Raeq), external hazard index, Hex, internal hazard index (Hin), representative index (Ig) and excess lifetime cancer risk calculated for soil and minerals samples compared favourably with the precautionary limits set by UNSCEAR. The excess lifetime cancer risk estimated for soil which was fairly insignificant compared with 0.05 prescribed by ICRP for low level radiation. The multivariate statistical (Pearson’s correlation and cluster) analysis showed some positive significant among 40K, 238U and 232Th, and with other radiological parameters in some mine fields. The study indicated that the minerals and soil samples from the mining sites will pose no major health risk to the public if used for industrial activities except for the salt minerals consumption

Determination of Radionuclide Levels in Soil and Water around Cement Companies in Port Harcourt

The study of the radionuclide concentration levels in soil and water samples in Eagle, Atlas and rock cement companies in Port Harcourt was carried out. Soil and water samples collected from the respective premises were analyzed using the gamma -ray spectrometry. The average absorbed dose rates of the soil samples were 49.27nGy/h, 45.21nGy/h and 42.33nGy/h for Eagle, Atlas and Rock cements respectively while the water values were 22.16nGy/h, 20.75nGy/h and 19.37nGy/h for the respective companies. Mean dose rate equivalents of 0.18mSv/y and 0.39mS/y were obtained for the water and soil samples. These results are lower than the International Commission on Radiological Protection (ICRP) maximum permitted limit and therefore, have no significance radiological health burden on the environment and the populace. @JASE

Natural Radioactivity Levels in Surface Soil of Ogba/Egbema/Ndoni Oil and Gas Fields

The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides viz. 226Ra, 232Th and 40K were determined in soil samples collected from twelve oil fields and their host communities, using gamma ray spectrometry. The soil activity ranges from 10.10 to 41.23 Bq/kg for 226Ra, 7.42 to 30.31 Bq/kg for 232Th and 92.42 to 482.79 Bq/kg for 40K with mean values of 19.16, 21.26 and 224.29 Bq/kg, respectively for host community soil. In the field soil sample, the activity concentration ranges from 16.27 to 52.19 Bq/kg for 226Ra, 9.72 to 34.13 Bq/kg for 232Th and 134.50 to 395.15 Bq/kg for 40K with mean values of 29.61, 17.41 and 262.63 Bq/kg, respectively. The concentrations of these radionuclides are compared with the values of the control samples and the UNSCEAR, 2000 standards of 35.0, 30.0 and 400 Bq/kg for 226Ra, 232Th and 40K respectively. The measured activity concentration of 226Ra, 232Th and 40K in soil is lower than the world average except in two oil fields that 226Ra and 40K exceeded the world average. Radium equivalent activities are calculated from the results to assess the radiation hazards arising due to the use of these soil samples in the construction of dwellings. All the soil samples have radium equivalent activities lower than the limit set in the UNSCEAR report (370 Bq/kg). The overall mean outdoor Absorbed Dose rate are 32.17 and 35.45nGy•h−1 respectively for host community soil and field soil samples. The corresponding effective dose calculated has mean values less than 1.0 mSvy-1, the limit set by WHO (2008). The hazard indices calculated were all less than unity (1) showing that all the soil/sediment samples sampled are still safe for building purpose since their radiological impact is minimal. The percentage contribution of each of these radionuclide are; 64.77% for radium-226, 3.13% for thorium-232 and 32.10% for potassium-40. The entire radiation hazard indices are within the acceptable limit therefore, no immediate health risk as a result of these radionuclide but continuous exposure may result to a significant health impact

Assessment of Gamma-Radiation Levels in Selected Oil Spilled Areas in Rivers State, Nigeria

A prelude radiological impact assessment of oil spillage on the oil spilled environment, those saddled with the responsibility of cleaning the spilled crude and the host/nearest communities residents in Rivers State Nigeria has been examined in-situ, using radiation meters (Digilert 100 nuclear radiation meter) and a geographical positioning system (GPS). Readings were taken twice in a month for three months in the five different oil spilled site and one measurement taken at a control site where there is no oil spillage but within oil bearing community. The average radiation values in all the oil spilled site is 0.019±0.006mRh-1, this is far above the 0.011±0.003mRh-1obtained for the control and ICRP 0.013±0.005mRh-1 world background levels. The average equivalent dose rate obtained in all the five studied site is 1.6mSvy-1 while the dose rate in the control is 0.93mSvy-1. The results showed that all the oil spilled sites yearly equivalent dose rate exceeded the 1mSvy-1 maximum permissible limit recommend for the public and non-nuclear industrial environment by International Council on Radiological Protection (ICRP,1999). All the oil spilled environment radiation levels exceeded the normal world average BIR level of 0.013mRh-1and other reported values in similar environment. This shows that the oil spilled environment have been impacted radiologically. This will pose some long-term health side effects on the clean-up workers and residents of the host communities. Interim proactive measures are recommended while further and a detail study is ongoing

Environmental sound quality of some selected flow Stations in the Niger delta of Nigeria

The measurements of environmental sound quality of some selected flow stations in the Niger-Delta area of Nigeria were carried out to obtain the noise distribution pattern of the stations. An in situ approach was adopted using direct reading calibrated digital noise level meters. The results show an average of 81.72 dB (A) and 84.74dB(A) for the East and West of the Niger-Delta respectively. The results are slightly below the FEPA recommended permissible limit for maximum of 8 hours, but the day and night continuity of the sound could therefore classify the results as hazardous and environmentally unfriendly to the host communities @ JASE

Editorial

No Abstract

Impact of environmental conditions on sub-surface storage tanks (part I)

The present investigation concentrates on the effects of environmental changes upon sub-surface storage tanks that are frequently used in the Niger Delta region and other parts of Nigeria for petroleum products. The research is part one of a long-term study that aims at the determination of corrosion rates of the under ground tanks within the Port Harcourt Municipality. Cast iron made storage tanks with gasoline fluid were buried under the soil at a depth of 4 m under various environment conditions. The simulated conditions include natural rain fail, temperature and acidic, alkaline and neutral soils. A control condition of neutral sea sand as base and filling materials were also investigated. After various exposure periods, the densities of the storage tanks, composition of soil, soil pH, corrosion rates and soil resistivities were determined. The experiments were repeated after every six months. Within the last three years, it has been observed that the corrosion rates of the tanks covered with cellophane materials were relatively less than those tanks that were buried directly within the soil except that of the control experiment. In addition the corrosion rates of tanks buried within the acidic environment were more than those buried within the alkaline and neutral soil conditions. Also, it was interestingly observed that the corrosion rates were generally and initially very rapid during the first year of the work, and decreased with time. Equally the water content of the soil was low. The soil resistivity increased relatively to the control sample site (G). (Journal of Applied Sciences & Environmental Management: 2002 6(2):79-84

Impact of Environmental Conditions on Sub-Surface Storage Tanks (Part I)

The present investigation concentrates on the effects of environmental changes upon sub-surface storage tanks that are frequently used in the Niger Delta region and other parts of Nigeria for Petroleum Products. The research is part one of a long-term study that aims at the determination of corrosion rates of the under ground tanks within the Port Harcourt Municipality. Cast iron made storage tanks with gasoline fluid were buried under the soil at a depth of 4 m under various environment conditions. The simulated conditions include natural rain fail, temperature and acidic, alkaline and neutral soils. A control condition of neutral sea sand as base and filling materials were also investigated. After various exposure periods, the densities of the storage tanks, composition of soil, soil pH, corrosion rates and soil resistivities were determined. The experiments were repeated after every six months. Within the last three years, it has been observed that the corrosion rates of the tanks covered with cellophane materials were relatively less than those tanks that were buried directly with in the soil except that of the control experiment. In addition the corrosion rates of tanks buried within the acidic environment were more than those buried within the alkaline and neutral soil conditions. Also, it was interestingly observed that the corrosion rates were generally and initially very rapid during the first year of the work, but with time it decreased. Equally the water content of the soil was low. The soil resistivity increased relatively to the control sample site. @ JASE