G. O. Avwiri

Inhibitive action of Vernonia amygdalina on the corrosion of aluminium alloys in acidic media

Abstract The action of Vernonia amygdalina (bitter leaf) on the acidic corrosion of 2S and 3RS alloys aluminium was studied using the weight loss method. The corrosion rates and inhibition efficiencies of the various aluminium coupons in the extract were calculated. The average corrosion rates of 6.5×10−3 and 5.5×10−3 mpy were obtained for 2S and 3SR alloys, respectively, in 0.1 M HNO3 while 18.2×10−3 and 10.4×10−3 mpy were calculated for the 2S and 3SR alloys in 0.1 M hydrochloric acid (HCl), respectively. The results further showed the highest inhibition efficiency of 49.5% for the 0.1 M HCl and 72.5% for 0.1 M HNO3, respectively. However, the 0.2g/l concentration showed a better performance in the inhibition of 0.1 M HCl for all samples.

Studies on the Radiological Impact of Oil and Gas Activities in Oil Mineral Lease 30 (Oml30) Oil Fields in Delta State, Nigeria

A preliminary studies on the radiological impact of oil and gas exploration activities in the oil and gas production land area of Delta State has been carried out insitu, using two radiation meters (Digilert 50 and 100) synchronized and calibrated and a geographical positioning system (GPS). Readings were taken in nine different facilities in each of the oil and gas fields and one sample each in their host communities. Measured radiation values in the oil field facilities ranged from 0.011 ± 0.003 mRh-1 in Evwreni campsite to 0.031 ± 0.01 mRh-1 at the Otorogu gas plant. Mean field exposure rates/equivalent dose rates in the oil fields ranged from 0.016 ± 0.006 mRh-1 (1.4 ± 0.5 mSvy-1) to 0.0213 ± 0.008 mRh-1 (1.8 ± 0.7 mSvy-1). While in the host communities values ranged from 0.011 ± 0.003 mRh-1 (0.9 ± 0.3 mSvy-1) in Evwreni community to 0.021 ± 0.007 mRh-1 (1.8 ± 0.7 mSvy-1) in Otujeremi town and the control study area value been 0.009 ± 0.002 mRh-1 (0.8 ± 0.06 mSvy-1). The results show that all the oil and gas fields and host communities except Evwreni community yearly radiation dose rate exceeded the 1mSvy-1 maximum permissible limit recommend for the public and non-nuclear industrial environment by International Council on Radiological Protection [1]. All the oil fields and host community except Ughelli East and Evwreni community radiation levels exceeded the normal world average BIR level of 0.013 mRh-1 and other reported values in similar environment. This shows that the oil fields environment and the host communities have been impacted radiologically. However, these results obtained may not have immediate health hazard, but will pose some long-term health side effects on the staff working in the facilities and residents of the host communities. Interim proactive measures are recommended while further and a detail study is ongoing.

Activity concentration and radiological impact assessment of 226Ra, 228Ra and 40K in drinking waters from (OML) 30, 58 and 61 oil fields and host communities in Niger Delta region of Nigeria

This paper presents the concentrations of naturally occurring radionuclides ((226)Ra, (228)Ra and (40)K) measured in hand dug wells, boreholes and river waters collected from three oil mineral leases (OML) 30, 58 & 61 oil and gas fields onshore of the Niger delta, using gamma spectroscopy. Fifty-four water samples from the three sources of drinking water supply were collected within the oil fields and host communities and three water samples from a control site. The results showed average activity concentrations of (226)Ra, (228)Ra and (40)K as 8.9 ± 1.0, 8.1 ± 0.9 and 39.8 ± 3.3 respectively for hand dug wells, 4.4 ± 0.8, 4.6 ± 0.5 and 28.5 ± 3.0 for borehole water and 8.2 ± 1.0, 6.7 ± 0.7 and 32.1 ± 3.5 for river water respectively. These (226)Ra, (228)Ra and (40)K average are well above the WHO permissible levels of 1.0, 0.1 and 10 BqL(-1) respectively and also above the control values. Although the hazard indices calculated are still within their tolerable levels, the estimated committed effective dose due to intake of the sampled water for all the four age groups considered are far above the ICPR 0.1 mSvyr(-1) maximum permissible limit. The result indicates some level of water pollution in the studied area.

Impact of Gas Exploitation on the Environmental Radioactivity of Ogba/Egbema/Ndoni Area, Nigeria:

A key component of the current national energy policy of Nigeria is to efficiently utilize her abundant natural gas reserves, especially in the energy sector. This paper reports a study of the terrestrial radioactivity in the industrial areas of Ogba/Egbema/Ndoni Local Government Area (ONELGA) of Rivers State. These industrial areas and their host communities were divided into six (6) zones, each having an oil and gas facility. An in-situ measurement was done using two well calibrated nuclear radiation meters (digilert–100 and digilert–50) and geographical positioning system (GPS). Ten readings were taken in each of the six zones and the host community at randomly selected sites, making a total of 60 sampling points. The mean site radiation level ranges from 0.014 ± 00.001mRh−1 (1.183 ± 0.060mSvy−1) to 0.018 ± 0.002mRh−1 (1.689± 0.085mSvy−1) while the mean community radiation level ranges from 0.014 ± 0.001mRh−1 (1.183 ± 0.06mSvy−1) to 0.017 ± 0.001mRh−1 (1.435 ± 0.072mSvyr1). The equivalent dose has an average range of 1.056 mSvy−1 to 2.871 mSvy−1, which is far below the recommended dose limit for radiological workers (20mSvy−1) but averagely above that for the general public (1mSvyr−1). Comparison of the measured radiation level of site locations with the normal background level shows that 43 locations, representing 71.7% of the sampled area, exceed the normal background level of 0.013mRh−1. This study indicates that there is no immediate radiological health hazard for the host communities and workers, however there may be long-term health challenges.

Cost-benefit analysis approach to risk assessment of natural radioactivity in powdered and liquid milk products consumed in Nigeria

ABSTRACT This article presents important facts on food safety in milk consumed in Nigeria that are in agreement with NAFDAC plan regarding the safety of food in Nigeria. The radioactivity con-centrations in powdered and liquid milk consumed in Nigeria were investigated using a sodium iodide (NaI(Tl)) detector. The activity concentrations of the three naturally occurring radionuclides, 226Ra, 232Th, and 40K, were measured in 10 brands of powdered milk and 11 brands of liquid milk. The results show that the mean activity concentration of 40K in the powder and liquid samples was 468.0 ± 72.7 Bq kg−1and 317.6 ± 58.5 Bq kg−1, respectively. The mean values for 226Ra for powdered and liquid milk were 19.2 ± 7.2 Bq kg−1 and 16.6 ± 6.3 Bq kg−1, respectively, while for 232Th it is 12.1 ± 4.8 Bq kg−1 and 10.6 ± 4.3 Bq kg−1, respectively. The average value of 40K in the powdered milk was found to be slightly above the standard value set by UNSCEAR for foodstuffs. The values of the calculated hazard indices and the radium equivalent of all milk samples were within the permissible limit set by UNSCEAR and other international regulatory bodies. However, the consumption of powdered and liquid milk by infants and children at the rate of 14 to 15 kg/year, from this analysis may result in radiation doses to vital organs above standard values. It is recommended that the amount of powdered milk consumed per year by infants and children should not exceed 7 and 11 kg/year while for liquid milk it should not exceed 8 and 13 kg/year, respectively. The cost-benefit analysis shows a low collective effective dose equivalent with a mean radiological index ratio of 1:30,839 for infants, 1:50,909 for children, and 1:247,145 for adults. The computed values of the total cost of the health detriment of consuming these examined milk products revealed that the child age group has the highest cost health detriment per capita dose, with an estimated total cost of health detriment of US

Terrestrial Radiation Around Oil And Gas Facilities In Ughelli Nigeria

17.256 million, followed by adults, with an estimated cost implication of US

γ-Spectroscopy measurement of natural radioactivity and assessment of radiation hazard indices in soil samples from oil fields environment of Delta State, Nigeria.

11.864 million; infants have the least, with an estimated cost implication of US

Determination of radionuclide levels in soil and water around cement companies in Port Harcourt

10.192 million. The overall results show that the powdered and liquid milk consumed in Nigeria are radiologically safe and may not cause any immediate radiation health hazard to consumers of the examined milk brands, while optimizing radiation protection using cost-benefit analysis is recommended.