Investigation into the physico-chemical properties and hydrochemical processes of groundwater from commercial boreholes In Yenagoa, Bayelsa State, Nigeria

The physico-chemical and hydrochemical study of commercial borehole waters in Yenagoa, Bayelsa State have been carried out. Eight commercial borehole water samples were analyze for various physico-chemical parameters using standard methods. The results obtained shows that the water samples quality examined compared favourably with WHO (1998) standard for drinking water. Although the values for pH (5.20±0.14, 6.10±0.10, 6.20±0.10, 6.20±0.20 in well 2, 5, 6, and 7 respectively), electrical conductivity (EC) of 520.00±5.50 mS/cm in well 7, biochemical oxygen demand (BOD) of 9.55±0.26 mg/L in well 3, Ca (9.25±0.10, 8.25±0.03 and 7.90±0.10 mg/L in well 2, 3, and 7 respectively) and all values obtained for Fe exceeded the WHO permissible limits for safe drinking water. The concentration of heavy metals; lead, copper, chromium, cadmium and arsenic (major sources of ground water pollution) were below detectable limit except at well 5, 6, and 7 where lead values of 0.03±0.001, 0.008±0.00, 0.04±0.00 mg/L respectively were obtained. The hydrochemical analysis shows that ion exchange and silicate weathering are the major prevailing hydrochemical processes in the groundwater. All the results obtained were however not significantly different from other reported values within the Niger Delta region. The higher concentrations of some of the parameters (pH, Ec, BOD, Fe, Ca2+) and the present of lead in some samples is an indication of some levels of pollution in the boreholes/ground water. This therefore calls for appropriate treatment measures before the consumption of these waters by the populace to avoid long term accumulative health problems of these pollutants. Recommendations on the strategies to reduce/eliminate some of these pollutants were made.Key words: Physico-chemical properties, hydrochemical processes, groundwater, boreholes, Yenagoa

Economic Approach to Risk Analysis of Naturally Occurring Radioactive Materials (NORMs) in Dairy Milk Products Consumed in Nigeria

One of the UN SDGs is for sustainable food for all; thus the need for safety in milk consumption in Nigeria which is also consonant with the NAFDAC regulatory plan of safety of food in Nigeria. This research work examined the radioactivity content in milks (powdered and liquid) consumed in Nigeria using sodium iodide (7.6 cm × 7.6 cm NaI(Tl)) detector. The estimated total cost of health detriment of consumption of the investigated milk products shows that the children age group has the highest cost health detriment per-caput dose with an estimated total cost of health detriment of US $17.26 million, followed by the adult age group with an estimated cost implication of US$11.86 million, and infants with the least computed cost implication of US $10.192 million. The overall results show that the milks consumed in Nigeria are radiologically safe and may not constitute any direct radiological health burden to consumers of these milk brands. Optimization of radiation protection mechanism for cost-benefit analysis is recommended

Thermal transport properties in GaAs (110)/GaAs (100) and GaAs/InAs interfaces by Reverse Non-equilibrium Molecular Dynamics

It is well known that the physics of thermal management is quite challenging as electronic device sizes are miniaturized and new materials are developed. This study calculates the thermal interface conductance (TIC), thermal interface resistance (TIR) and thermal grain conductivity across GaAs(110)/GaAs(100) and GaAs/InAs interfaces using the reverse non-equilibrium molecular dynamics (RNEMD) technique. Data obtained showed that, at GaAs(110)/GaAs(100) the TIC increased from 0.912 x 10-9 (W/K) to 1.433 x 10-9 (W/K), the TIR decreased from 1.096 x 109 (K/W) to 0.697 x 109 (K/W) between 300 K and 1000 K, and the thermal grain conductivity increased from 7.47 (W/mK) to 15.52 (W/mK) and 7.48 (W/mK) to 80.71 (W/mK) between 15 Å and 55 Å at 300 K. At GaAs/InAs interface the TIC increased from 7.228 x -10 (W/K) to 14.498 x 10-10 (W/K) and the TIR decreased from 0.138 x 1010 (K/W) to 0.068 x 1010 (K/W) between 300 K and 700 K, respectively. It was observed that, as temperature is increased the TIC and TIR for both materials change significantly. This trend is consistent with previous molecular dynamic studies of interface materials.Keywords: Interface conductance, thermal resistance, grain conductivity, temperature

Gross &#945 and &#946 Activity Concentration and Estimation of Adults and Infants Dose intake in Surface and Ground Water of Ten Oil Fields Environment in Western Niger Delta of Nigeria

The oil and gas rich Niger Delta region of Nigeria is characterized by environmental degradation leading to environmental pollution from oil and gas activities. This study examined the gross α and β activity in thirty (river/stream, well and tap) water samples collected from ten oil fields in the Western Niger Delta region of Nigeria. The counting system employed in this analysis is the Gas-flow proportional counter {Eurisys Measure IN20 low- background multiple (eight) channel counter}. Gross alpha activity concentration range from 0.01±0.002 to 0.7±0.01 (0.15±0.003) Bql-1, 0.01±0.003 to 0.5±0.01 (0.1±0.003)Bql-1and 0.02±0.001 to 35.1±1.1 (4.1±0.1) Bql-1 while beta activity concentration ranged from 1.1±0.04 to 13.2±0.1 (6.0±0.1) Bql-1, 0.7±0.1 to 54.7±1.3 (8.9±0.2)Bql-1 and 0.7±0.03 to 151.2±1.8 (40.1±0.9)Bql-1 for well, tap and river waters respectively. Correlation value between α and β activities in well, tap and river water is 0.025, 0.047 and 0.512 respectively. The results show that except for the alpha activity in the tap water samples, the average natural activity concentrations of α- and β-emitting radionuclides in the samples are slightly above the WHO recommended limit. For all samples the gross β activities are higher than the corresponding gross α activities. The mean effective equivalent dose intake per year due to alpha activity in the water samples for adults and infants are: 76.4±1.8 and 20.9±55μSvy-1, 54.6±1.3 and 14.9±0.4 μSvy-1, and 2118±70 and 584±19.2μSvy-1 in well, tap, and river water samples respectively. The results obtained for dose intake are below the WHO recommended reference level of 0.1mSvy-1, except for the water sample from Uzere river. This study indicates that the water sources evaluated, especially the rivers, are contaminated radiologically. @JASE

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

3-D Seismic Structural Interpretation of High Field Offshore Western Niger Delta

Seismic Structural interpretation of subsurface system is a vital tool in mapping source rocks and good trapping system which enhances good understanding of the subsurface system for productive drilling operation. This study is geared towards mapping the structural traps available within the hydrocarbon bearing zones of the “High field” with the use of well log and 3D seismic data. Seven horizons (H1, H2, H3, H4, H5, H6 and H7) were identified on well logs using gamma ray log and resistivity logs. Nine (9) faults were mapped on seismic sections across the field, two (2) of which are major growth faults (F1 and F2), two (2) synthetic faults (F3 and F7) and five (5) antithetic faults (F4, F5, F6, F8 and F9). Rollover anticlines which are structural closure and displayed on the depth structural maps suggest probable hydrocarbon accumulation at the down throw side of the fault F1. Structural interpretation of high field has revealed a highly fault assisted reservoir which depicts the tectonic setting of Niger Delta basin

Radiological impact of oil and Gas Activities in selected oil fields in Production Land Area of Delta State, Nigeria

A study of the radiological impact of oil and gas exploration activities in the production land area of Delta State has been carried out in-situ using two synchronized and calibrated radiation meters (Digilert 50 and 100) and a geographical positioning system (GPS). Ten oil field facilities were studied. At each facility, nine sampling locations and their host communities were evaluated making a total of 100 study points. Measured exposure rate in the oil field facilities ranged from 0.011\ub10.003mRh-1 in Evwreni camp site to 0.031\ub10.01mRh-1 at the Otorogu gas plant. Mean field exposure rates/equivalent dose rates ranged from 0.016\ub10.006mRh-1(0.839\ub10.34mSvy-1) to 0.0213\ub10.008mRh-1(1.134\ub10.44mSvy-1). In the host communities the values ranged from 0.0115\ub10.003mRh-1 (0.612\ub10.16mSvy-1) in Evwreni community to 0.021\ub10.007mRh-1 (1.117\ub10.37mSvy-1) in Otujeremi town, while for the control study area the value obtained was 0.009\ub10.002mRh-1(0.479\ub10.11mSvy-1). The results show that the radiation levels for the Ughelli East, Kokori, Eriemu, Evwreni, Eriemu, Oweh, Olomoro-Oleh oil and gas fields are within the 1mSvy-1 maximum permissible limit recommended for the public and non-nuclear industrial environment, while the levels for the fields at Otorogu, Ughelli West, Afiesere and Uzere West and East and the host communities of Olomoro, Uzere and Emeragha exceeded the maximum recommended value, an indication that the oil fields and host communities environment 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 @JASE

Gross \u3b1 and \u3b2 Activity Concentration and Estimation of Adults and Infants Dose intake in Surface and Ground Water of Ten Oil Fields Environment in Western Niger Delta of Nigeria

The oil and gas rich Niger Delta region of Nigeria is characterized by environmental degradation leading to environmental pollution from oil and gas activities. This study examined the gross \u3b1 and \u3b2 activity in thirty (river/stream, well and tap) water samples collected from ten oil fields in the Western Niger Delta region of Nigeria. The counting system employed in this analysis is the Gas-flow proportional counter {Eurisys Measure IN20 low- background multiple (eight) channel counter}. Gross alpha activity concentration range from 0.01\ub10.002 to 0.7\ub10.01 (0.15\ub10.003) Bql-1, 0.01\ub10.003 to 0.5\ub10.01 (0.1\ub10.003)Bql-1 and 0.02\ub10.001 to 35.1\ub11.1 (4.1\ub10.1) Bql-1 while beta activity concentration ranged from 1.1\ub10.04 to 13.2\ub10.1 (6.0\ub10.1) Bql-1, 0.7\ub10.1 to 54.7\ub11.3 (8.9\ub10.2)Bql-1 and 0.7\ub10.03 to 151.2\ub11.8 (40.1\ub10.9)Bql-1 for well, tap and river waters respectively. Correlation value between \u3b1 and \u3b2 activities in well, tap and river water is 0.025, 0.047 and 0.512 respectively. The results show that except for the alpha activity in the tap water samples, the average natural activity concentrations of \u3b1- and \u3b2-emitting radionuclides in the samples are slightly above the WHO recommended limit. For all samples the gross \u3b2 activities are higher than the corresponding gross \u3b1 activities. The mean effective equivalent dose intake per year due to alpha activity in the water samples for adults and infants are: 76.4\ub11.8 and 20.9\ub155\u3bcSvy-1, 54.6\ub11.3 and 14.9\ub10.4\u3bcSvy-1, and 2118\ub170 and 584\ub119.2\u3bcSvy-1 in well, tap, and river water samples respectively. The results obtained for dose intake are below the WHO recommended reference level of 0.1mSvy-1, except for the water sample from Uzere river. This study indicates that the water sources evaluated, especially the rivers, are contaminated radiologically. @JASE

Radioactivity content surveillance on canned food products in Nigeria

The radionuclides surveillance on imported can food products in Nigeria market has been investigated using High purity Germanium detector. The radioactivity concentrations of 226Ra, 232Th, 40K, 210Pb and 137Cs in selected brands of imported canned food products categorized into staple foodstuffs, beef and seafood were analyzed. The results obtained for staple foodstuffs shows a mean activity value of 12.33±3.68, 12.35±4.62, 51.48±15.12, 2.65±0.18 and 0.61±0.27 Bq kg-1 for 226Ra, 232Th, 40K, 210Pb and 137Cs respectively, while in beef food products, it is 14.41±4.79, 14.12±4.83, 50.44±14.80, 1.11± 0.07 and 0.32±0.20 Bq kg-1 respectively, and for seafood products it is 17.95±5.71, 16.24±5.48, 61.65±18.07, 1.17±0.13 and ND Bq kg-1 respectively. The overall results indicate that the natural radioactivity in the three categories of canned foodstuffs examined are well below the UNSCEAR and other regulatory bodies recommended permissible limits. The presence of 137Cs in some samples potent some degree of heavy metal contamination of those foodstuffs. The computed dose to essential organs and tissues indicates a highest dose level of 0.2 mSvy-1 which is well within the 1mSvy-1 recommended permissible level of the public. The calculated collective effective dose equivalent revealed that 97,463,16 of the total population are exposed to radiation from ingestion of the canned foods with adults most impacted. The total health detriment indicates radiological risk ratio of 1:2238 for infants, 1:2583 for children and 1:4238 for adults. From the estimated costdetriment, it is obvious that the economic benefits which is directly proportional to cost of purchase and importation put at about nine billion US dollars annually derived from consuming these imported canned food products is far above the health detriment. &nbsp