This document presents a risk assessment model for abandoned radioactive logging sources in oil wells in Nigeria. The model includes four components: a source term model, barrier failure model, geosphere model, biosphere model, and dose/health effect model. It estimates the time-dependent annual release rate and dose rate of radionuclides from abandoned sources. The highest estimated annual dose was less than the individual dose limit. The highest estimated cancer death rate was lower than background radiation but higher than a low-level waste repository. An abandonment procedure was developed to manage risk and reduce it to a minimum.
Evaluation of Radiation Emmission from Refuse Dump Sites in Owerri, NigeriaIOSR Journals
The natural radioactivity concentrations from 40 different locations of waste dump sites in Owerri, Imo state Nigeria, has been measured using a gamma – ray spectrometer. The results indicate that the ranges of activity concentrations of 40K, 226Ra and 323Th in the samples were ˂17.2 – 686.17 BqKg-1 , ˂ 4.2 – 103.51 BqKg-1 and ˂ 5.1 – 65.28 BqKg-1 respectively. The highest outdoor effective dose obtained was 65.28 μSv.y-1 which is less than the world average outdoor value of 70 μSv.y-1 given by United Nations Scientific Committee on the Effect of Atomic Radiation ( UNSCEAR )
Dust Characterization and Source Apportionment at an Active Surface Mine in West Virginia by Dr. Nick Basta, Shane Whitacre, Dr. Vlad Kecojevic, Ali Lashgari, and Dr. Braden Lusk
MODELING THE EFFECT OF ATMOSPHERIC STABILITY, NITROGEN OXIDE AND CARBON MONOX...IAEME Publication
Modeling the effect of atmospheric stability, Nitrogen oxide and carbon monoxide on ozone formation is presented. The observation of NO2, CO, Ozone and meteorological parameters were carried out in 5 predefined locations in Ogba/Egbema/Ndoni Local Government area in Nigeria. A model which was dependent CO, NO and solar radiation was developed and it attained a correlation coefficient of 0.6. Sensitivity analysis was carried out of the independent variables of the developed model and NO2 showed no significance to the formation of Ozone and a 0.5% coefficient of correlation in the direct relationship to Ozone formation.
The document analyzes soil samples collected from eastern Haryana, India to estimate levels of alpha radioactivity. Radon exhalation rates were measured using solid state nuclear track detectors exposed in the soil samples for 100 days. Track density measurements indicated radon concentrations ranging from 197 to 1495 Bq/m3 in samples from Karnal, 708 to 2243 Bq/m3 in samples from Panipat, and 905 to 2204 Bq/m3 in samples from Sonipat. Mass and surface exhalation rates were also calculated from the radon concentration data. The measurements found normal to higher levels of natural radioactivity in the soil samples, but within internationally accepted safe limits.
This study presents results of Activity Concentrations, Absorbed dose rate and the Annual Effective dose rates of naturally occurring radionuclides (40K, 232Th and 226Ra) absorbed in 8 soil samples collected from different areas within the Ajiwei mining sites in Niger State, North Central Nigeria. A laboratory γ-ray spectrometry NaI (Tl) at the Centre for Energy Research and Training (CERT), Ahmadu Bello University Zaria, was used to carry out the analysis of the soil samples. The values of Activity Concentration for 40K ranged from 421.6174 ± 7.9316 to 768.7403 ± 7.9315; for 226Ra it ranged from 20.6257 ± 2.0858 to 44.0324 ± 5.0985 and for 232Th the ranged is from 23.7172 ± 1.3683 to 62.7137 ± 4.1049 Bq.Kg-1. While the Absorbed Dose for 40K ranged from 17.5814 ± 0.3307 to 32.0565 ± 0.3307 ŋGy.h-1, for 226Ra the range is from 9.5291 ± 0.9636 to 20.3430 ± 2.3555 ŋGy.h-1 and for 232Th range from 14.3252 ± 0.4414 to 37.8791 ± 2.4794 ŋGy.h-1. The total average Absorbed Dose rate of the 8 soil samples collected is 63.7877 ŋGy.h-1 and the estimated Annual Effective Dose for the sampled areas range from 0.0636- 0.1028mSvy-1 (i.e 64 – 103 μSv.y-1), with an average Annual Effective Dose of 0.0782 mSv.y-1 (i.e. 78.2 μSv.y-1). These results show’s that the radiation exposure level reaching members of the public in the study areas is lower than the recommended limit value of 1 mSv.y-1 (UNSCEAR, 2000). Also the mean Radium Equivalents obtained ranged from 107.3259 BqKg-1 (AJ1) to 179.4064 BqKg-1 (AJ4). These results show that the recommended Radium Equivalent Concentration is ≤ 370 BqKg-1 which is the requirement for soil materials to be used for dwellings, this implies that the soil from this site is suitable use for residential buildings. The mean External Hazard Index ( Hext ) ranged from 0.1229 Bqkg-1 (AJ3) to 0.4226 Bqkg-1 (AJ7).. While the maximum allowed value of (Hext = 1) corresponds to the upper limit of Raeq (370 BqKg-1) in order to limit the external gamma radiation dose from the soil materials to 1.5 mGy y-1. That is, this Index should be equal to or less than unity (Hext ≤ = 1). Furthermore, the mean Internal Hazard Index (Hext) ranged from 0.3456 Bqkg-1 (AJ1) to 0.6453 Bqkg-1 (AJ2) .Finally, the mean value of the Excess Alpha Radiation (Iα) ranged from 0.1031 Bq.Kg-1 (AJ1) to 0.2202 Bq.Kg-1 (AJ3. All these values for Iα are below the maximum permissible value of Iα= 1 which corresponds to 200 Bq.Kg-1. It can therefore be said that no radiological hazard is envisaged to dwellers of the study areas and the miners working on those sites area.
Baseline concentration of Cd, Co, Cr, Cu, Pb, Ni and Zn in surface soils of SAElize Herselman
THE AIM OF THIS STUDY WAS TO DRAW up baseline concentrations for several environmentally important trace elements in South African soils. A major inventory of
some 4500 soil profiles has been compiled in South Africa over the past three decades and information on chemical composition can now readily be generated for the country as a
whole.
Low resource deep learning to detect waste intensity in the river flowjournalBEEI
This document summarizes a study that used the YOLO v3 deep learning algorithm to detect waste in river flows and calculate waste intensity. Researchers collected 340 images of waste in rivers to use as a training dataset for a YOLO v3 model. The model was tested on videos of river flows and achieved 98.74% confidence in detecting waste objects. The resulting application can detect a variety of waste sizes, from small food wrappers to large objects, and count the number of waste items intersecting a drawn reference line in each video frame. This waste detection and counting system aims to help monitor waste in rivers and predict when river cleaning is needed.
Evaluation of Radiation Emmission from Refuse Dump Sites in Owerri, NigeriaIOSR Journals
The natural radioactivity concentrations from 40 different locations of waste dump sites in Owerri, Imo state Nigeria, has been measured using a gamma – ray spectrometer. The results indicate that the ranges of activity concentrations of 40K, 226Ra and 323Th in the samples were ˂17.2 – 686.17 BqKg-1 , ˂ 4.2 – 103.51 BqKg-1 and ˂ 5.1 – 65.28 BqKg-1 respectively. The highest outdoor effective dose obtained was 65.28 μSv.y-1 which is less than the world average outdoor value of 70 μSv.y-1 given by United Nations Scientific Committee on the Effect of Atomic Radiation ( UNSCEAR )
Dust Characterization and Source Apportionment at an Active Surface Mine in West Virginia by Dr. Nick Basta, Shane Whitacre, Dr. Vlad Kecojevic, Ali Lashgari, and Dr. Braden Lusk
MODELING THE EFFECT OF ATMOSPHERIC STABILITY, NITROGEN OXIDE AND CARBON MONOX...IAEME Publication
Modeling the effect of atmospheric stability, Nitrogen oxide and carbon monoxide on ozone formation is presented. The observation of NO2, CO, Ozone and meteorological parameters were carried out in 5 predefined locations in Ogba/Egbema/Ndoni Local Government area in Nigeria. A model which was dependent CO, NO and solar radiation was developed and it attained a correlation coefficient of 0.6. Sensitivity analysis was carried out of the independent variables of the developed model and NO2 showed no significance to the formation of Ozone and a 0.5% coefficient of correlation in the direct relationship to Ozone formation.
The document analyzes soil samples collected from eastern Haryana, India to estimate levels of alpha radioactivity. Radon exhalation rates were measured using solid state nuclear track detectors exposed in the soil samples for 100 days. Track density measurements indicated radon concentrations ranging from 197 to 1495 Bq/m3 in samples from Karnal, 708 to 2243 Bq/m3 in samples from Panipat, and 905 to 2204 Bq/m3 in samples from Sonipat. Mass and surface exhalation rates were also calculated from the radon concentration data. The measurements found normal to higher levels of natural radioactivity in the soil samples, but within internationally accepted safe limits.
This study presents results of Activity Concentrations, Absorbed dose rate and the Annual Effective dose rates of naturally occurring radionuclides (40K, 232Th and 226Ra) absorbed in 8 soil samples collected from different areas within the Ajiwei mining sites in Niger State, North Central Nigeria. A laboratory γ-ray spectrometry NaI (Tl) at the Centre for Energy Research and Training (CERT), Ahmadu Bello University Zaria, was used to carry out the analysis of the soil samples. The values of Activity Concentration for 40K ranged from 421.6174 ± 7.9316 to 768.7403 ± 7.9315; for 226Ra it ranged from 20.6257 ± 2.0858 to 44.0324 ± 5.0985 and for 232Th the ranged is from 23.7172 ± 1.3683 to 62.7137 ± 4.1049 Bq.Kg-1. While the Absorbed Dose for 40K ranged from 17.5814 ± 0.3307 to 32.0565 ± 0.3307 ŋGy.h-1, for 226Ra the range is from 9.5291 ± 0.9636 to 20.3430 ± 2.3555 ŋGy.h-1 and for 232Th range from 14.3252 ± 0.4414 to 37.8791 ± 2.4794 ŋGy.h-1. The total average Absorbed Dose rate of the 8 soil samples collected is 63.7877 ŋGy.h-1 and the estimated Annual Effective Dose for the sampled areas range from 0.0636- 0.1028mSvy-1 (i.e 64 – 103 μSv.y-1), with an average Annual Effective Dose of 0.0782 mSv.y-1 (i.e. 78.2 μSv.y-1). These results show’s that the radiation exposure level reaching members of the public in the study areas is lower than the recommended limit value of 1 mSv.y-1 (UNSCEAR, 2000). Also the mean Radium Equivalents obtained ranged from 107.3259 BqKg-1 (AJ1) to 179.4064 BqKg-1 (AJ4). These results show that the recommended Radium Equivalent Concentration is ≤ 370 BqKg-1 which is the requirement for soil materials to be used for dwellings, this implies that the soil from this site is suitable use for residential buildings. The mean External Hazard Index ( Hext ) ranged from 0.1229 Bqkg-1 (AJ3) to 0.4226 Bqkg-1 (AJ7).. While the maximum allowed value of (Hext = 1) corresponds to the upper limit of Raeq (370 BqKg-1) in order to limit the external gamma radiation dose from the soil materials to 1.5 mGy y-1. That is, this Index should be equal to or less than unity (Hext ≤ = 1). Furthermore, the mean Internal Hazard Index (Hext) ranged from 0.3456 Bqkg-1 (AJ1) to 0.6453 Bqkg-1 (AJ2) .Finally, the mean value of the Excess Alpha Radiation (Iα) ranged from 0.1031 Bq.Kg-1 (AJ1) to 0.2202 Bq.Kg-1 (AJ3. All these values for Iα are below the maximum permissible value of Iα= 1 which corresponds to 200 Bq.Kg-1. It can therefore be said that no radiological hazard is envisaged to dwellers of the study areas and the miners working on those sites area.
Baseline concentration of Cd, Co, Cr, Cu, Pb, Ni and Zn in surface soils of SAElize Herselman
THE AIM OF THIS STUDY WAS TO DRAW up baseline concentrations for several environmentally important trace elements in South African soils. A major inventory of
some 4500 soil profiles has been compiled in South Africa over the past three decades and information on chemical composition can now readily be generated for the country as a
whole.
Low resource deep learning to detect waste intensity in the river flowjournalBEEI
This document summarizes a study that used the YOLO v3 deep learning algorithm to detect waste in river flows and calculate waste intensity. Researchers collected 340 images of waste in rivers to use as a training dataset for a YOLO v3 model. The model was tested on videos of river flows and achieved 98.74% confidence in detecting waste objects. The resulting application can detect a variety of waste sizes, from small food wrappers to large objects, and count the number of waste items intersecting a drawn reference line in each video frame. This waste detection and counting system aims to help monitor waste in rivers and predict when river cleaning is needed.
IRJET- Waste water treatment by Tea Waste, Alum, Pre-Aluminium ChlorideIRJET Journal
This document summarizes a study on using tea waste, alum, and pre-aluminum chloride to treat wastewater from Tighra reservoir in Gwalior, India. Heavy metals like chromium, lead, cadmium, and nickel were found in high concentrations in the reservoir water due to religious practices of immersing idols. The study collected and processed tea waste to produce an adsorbent to remove heavy metals. Testing of water samples before and after treatment showed the tea waste adsorbent was able to remove up to 25.6% of heavy metals. The results indicate tea waste has potential for wastewater treatment and removing pollutants from water bodies.
This study investigated spatial patterns of air pollution in an industrial estate in Lagos, Nigeria. Seven sampling sites were selected to measure levels of particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), hydrogen sulfide (H2S), methane (CH4), and noise. Statistical analysis using principal component analysis and cluster analysis revealed two main sources of air pollution: traffic emissions contributed most to NO2 levels, while fossil fuel combustion and industrial sources contributed most to SO2, CO, and H2S levels. The levels of SO2, NO2, and PM10 exceeded national standards at some sites, indicating traffic and industrial pollution are problems. Appropriate vehicle emission controls
Assessment of Natural Radioactivity in Soil and Water Samples from Aden Gover...paperpublications3
Abstract:The level of natural radioactivity in soils and water of 74 samples collected from locations at Aden governorate south of Yemen was measured. Concentrations of radionuclides in soils and water samples were determined by gamma-ray spectrometer using a NaI (Tl) detector with specially designed shield. The mean activity level of the natural radionuclides 226Ra, 232Th and 40K is 30.41 ±2.4, 36.26 ±2.9 and 358.12±26.54 Bq kg-1, respectively. These values are well within values reported elsewhere in the country and in other countries with similar environments. The study also examined some radiation hazard indices. The mean values obtained are, 215±37Bq kg-1, 50.10±6 nGy h-1, 0.34mSv y-1, 0.30 and 0.34 for Radium Equivalent Activity (Raeq), Absorbed Dose Rates (D), Annual Effective Dose Rates (Eff Dose), External Hazard Index (Hex) and Internal Hazard Index (Hin) respectively. All the health hazard indices are well below their recommended limits. The paper recommends further studies to estimate internal and external doses from other suspected radiological sources to the population in Aden governorate.
Keywords:Absorbed dose, south Yemen, Aden governorate, Water, Soil, Natural Radioactivity.
This document summarizes an inverse modeling study of carbonyl sulfide (COS) using the TM5-4DVAR model. The objectives were to 1) implement an inverse system for COS, carbon disulfide (CS2), and dimethyl sulfide (DMS), 2) invert COS based on closing global budgets, and 3) validate the model with independent HIPPO and aircraft profile data. The results showed missing COS emissions in the tropics and additional sinks at high latitudes in the Northern Hemisphere. Assimilating both NOAA and HIPPO data into the model improved agreement with independent validation data compared to using NOAA data alone. Future work will include assimilating satellite observations
This document presents the results of a systematic study measuring indoor radon concentration levels across the main urban areas of Cyprus. Between 2004-2012, over 400 measurements were taken using portable detectors in the districts of Lefkosia, Lemesos, Larnaka, and Pafos, which are home to 67.3% of Cyprus' population. The districts were divided into 189 grid cells of 1 km2 each. Grid cell mean radon concentrations ranged from 1.7 to 86.4 Bq/m3, with an overall mean of 14.3 Bq/m3. This is lower than the estimated global average of 39 Bq/m3. Equivalent annual effective dose rates were also calculated and
Assessment of the Environmental Impact of Landfill Sites in the East Riding o...Mark Kwabena Gadogbe
This document summarizes a study that used GIS spatial analysis and multi-criteria evaluation to identify areas in the East Riding of Yorkshire, UK that are most sensitive to environmental impacts from landfill leachate and to identify the three landfill sites that pose the highest risk. The methodology weighted factors like proximity to residential areas, protected sites, and water sources to produce a sensitivity map. The analysis found 11 high-risk landfill sites, and identified Carnaby (Moor Lane), Gransmoor Quarry Site A, and Thorneholme as having the highest pollution potential due to size, waste types, and nearby water sources and boreholes.
Elemental Analysis of Soil samples of Cox’s Bazar Sea-Beach Area Using PIXE ...AM Publications
This document summarizes an elemental analysis of soil samples from Cox's Bazar, Bangladesh using the PIXE technique. Soil samples were collected from different distances from the sea and analyzed using a proton beam. Notably high concentrations of tantalum were found in samples near sea water compared to other elements. Samples from cultivated areas contained high levels of tantalum, potassium, and calcium. The sample from a populated area showed high concentrations of iron, silicon, and rubidium. The data on elemental compositions can help assess environmental conditions and risks to human and ecological health in the area.
SIMULATION OF ATMOSPHERIC POLLUTANTS DISPERSION IN AN URBAN ENVIRONMENTAM Publications
Interest in air pollution investigation of urban environment due to existence of industrial and commercial activities along with vehicular emission and existence of buildings and streets which setup natural barrier for pollutant dispersion in the urban environment has increased. The air pollution modelling is a multidisciplinary subject when the entire cities are taken under consideration where urban planning and geometries are complex which needs a large software packages to be developed like Operational Street Pollution Model (OSPM), California Line Source model (CALINE series) etc. On overviewing various works it can be summarized that the air pollutant dispersion in urban street canyons and all linked phenomenon such as wind flow, pollutant concentrations, temperature distribution etc. generally depend on wind speed and direction, building heights and density, road width, source and intensity of air pollution, meteorological variables like temperature, humidity etc. A unique and surprising case is observed every time on numerous combinations of these factors. The main aim of this study is to simulate the atmospheric pollutant dispersion for given pollutant like carbon monoxide, sulphur dioxide and nitrogen dioxide and given atmospheric conditions like wind speed and direction. Computational Fluid Dynamics (CFD) simulation for analysing the atmospheric pollutant dispersion is done after natural airflow analysis. Volume rendering is done for variables such as phase 2 volume fraction and velocity with resolution as 250 pixels per inch and transparency as 20%. It can be observed that all the three pollutant namely nitrogen dioxide, sulphur dioxide and carbon monoxide the phase 2 volume fraction changes from 0 to 1. The wind velocity changes from 3.395×10-13 m/s to 1.692×102 m/s. The dispersion of pollutants follow the sequence Sulphur dioxide>Carbon monoxide>Nitrogen dioxide.
IRJET- Analysis of Sediment Contamination of Deepor Beel, Guwahati, Assam, IndiaIRJET Journal
This document analyzes sediment contamination in Deepor Beel Lake located in Guwahati, Assam, India. Six students and one professor collected sediment samples from four locations around the lake on a monthly basis and analyzed physical and chemical parameters including pH, heavy metals, etc. Their analysis found pollution levels and heavy metal concentrations in sediments varied between locations and over time, with highest levels near waste dumping sites. The study suggests sediment contamination poses a threat to local groundwater and highlights the need for preventive measures to protect the lake's water quality.
This document summarizes a study that used portable X-ray fluorescence spectrometry (XRF) to rapidly detect toxic metals like lead in non-crushed oyster shells. The researchers developed a methodology to use a portable XRF to simultaneously detect multiple elements in oyster shells without crushing them. Lead contamination was confirmed in contaminated oyster shells using both XRF and scanning electron microscopy with energy dispersive spectroscopy (SEMeEDS). The portable XRF provided a quick, non-destructive, and cost-effective way to assess lead contamination in oyster shells.
President Obama announced a new climate plan that includes setting limits on carbon emissions from US power plants. The plan aims to reduce emissions from fossil fuel energy sources and increase renewable energy and energy efficiency. Researchers from the Atmospheric Sciences Research Center at SUNY and Rensselaer Polytechnic Institute studied the catalytic reactivity of airborne particulate matter and its potential role in atmospheric chemical reactions. Their research examined particles collected from power plant boilers and simulated samples to assess the impact of heterogeneous catalysis on the rates of pollutant gases in the atmosphere.
Study and analysis of the concentrations of tropospheric ozone in the city of...Enrique Posada
The document analyzes data from 9 air quality monitoring stations in Medellin, Colombia between 2014-2015. It finds:
- The average hourly ozone concentration was 15.7 ppb, with only 1.29% of readings exceeding the standard of 61 ppb.
- Concentrations were highest in southern stations and lowest in northern stations, peaking between 11am-3pm daily.
- Concentrations correlated with sunlight and were higher further from the river and in more urban areas.
- The situation was not considered serious from a public health perspective but deserves continued monitoring.
LGC is addressing the UK's chemical and bio-measurement needs to support key industries like healthcare, food, and energy. LGC researchers are developing new methods to accurately measure pollutants like PBDEs in water samples to help enforce the EU Water Framework Directive and clean up rivers and lakes. They are also studying microbial communities as bioindicators of water quality to rapidly assess the impacts of pollution and help mitigate threats to water resources.
This document is a summary for policymakers from the Working Group I contribution to the IPCC Fourth Assessment Report. It describes the key findings regarding human and natural drivers of climate change based on improved data, analyses, and understanding since the Third Assessment Report. The summary highlights that atmospheric concentrations of greenhouse gases like carbon dioxide, methane and nitrous oxide have increased significantly due to human activities since 1750 and now far exceed pre-industrial levels. It also notes that human activities have very likely caused warming of the climate system through radiative forcings, with a best estimate of +1.6 W/m2 net forcing since 1750. Direct observations show warming of the atmosphere and ocean, shrinking glaciers and ice sheets, rising
This document provides a literature review on the use of nanoparticles for removing contaminants from wastewater. It discusses nanoparticles that have been used to remove various types of contaminants including metals, non-metals, organic and inorganic pollutants, and microorganisms. The document surveys research on nanoparticles for removing specific contaminants such as heavy metals, pesticides, mercury, and pathogenic bacteria. It also examines factors that influence contaminant removal like nanoparticle size, surface chemistry, adsorption properties, and reusability. The literature demonstrates that nanoparticles show potential for wastewater treatment due to their large surface area and chemical reactivity.
2013 Global Carbon Budget (Global Carbon Project)Future Earth
The Global Carbon Project's 2013 global carbon budget.
Published 19 November 2013.
See website for more information
http://www.globalcarbonproject.org/carbonbudget/index.htm
The Global Carbon Project (GCP) is a project of the International Geosphere-Biosphere Programme. GCP's chair Corinne Le Quéré is a member of the Future Earth scientific committee.
The Efficiency of Eicchornia crassipes in the Phytoremediation of Waste Water...iosrjce
The study involved a laboratory experiment on the use of Eicchornia crassipes in the
phytoremediation of a stream polluted by waste water from Kaduna Refinery and Petrochemical Company. The
physiochemical characteristics of the waste water were determined before and after the treatment. The
experiment lasted for three weeks and the rate of reduction was recorded. The highest rate of mean reduction
were for heavy metals accounting 99.0%, 95.0%, 96.3%, 100%, 99.3% and 94.3% of Cd, Hg, Zn, Mn, Pb and
Ag respectively. Other physiochemical parameters include Total Dissolved Solids (TDS) 90%, Chemical Oxygen
Demand (COD) 54.3%, Nitrate 86.3%, Biochemical Oxygen demand (BOD) 13.7%, Conductivity 11%, Total
suspended Solids (TSS) 55.7%, Turbidity 18%, 87% Total Solids (TS) and the pH 4%. Ecchornia crassipes is a
suitable candidate for effective phytoremediation of water from Romi stream.
This document discusses using liquid carbon dioxide as an alternative to water for hydraulic fracturing in shale gas extraction in India. The objective is enhanced gas recovery from Indian shales while sequestering the greenhouse gas carbon dioxide. Methods suggested include flooding experiments to model methane desorption and carbon dioxide adsorption capacities of Indian shale basins based on their total organic content. Previous works demonstrated that organic matter preferentially adsorbs carbon dioxide over methane, and that imaging techniques can provide insights into shale microstructure and flow properties. The conclusion is that using carbon dioxide for fracturing and sequestration could make shale gas extraction more sustainable while providing economic storage of carbon dioxide.
Annual atmospheric corrosion rate and dose-response function for carbon steel...Carlos Arroyave
This paper presents an assessment on the behavior of plain carbon steel exposure to the atmosphere of Bogotá. The main climate and environmental parameters, including relative humidity (RH), temperature (T), sulphur dioxide deposition (DSO2) and particulate matter deposition (DPM) were measured. Furthermore, mass loss of AISI/SAE 1006 plain carbon steel coupons was measured along one year. In this case, coupons were exposed in eight test sites located across the city of Bogotá. Results show that the corrosion rate of carbon steel is less than 35 μm yr–1 after one year. It was found that the west part of the city has the greatest aggressivity, which has the highest levels of DPM and DSO2, related with the characteristics of the anthropogenic activities distribution across the city. A dose-response function of plain carbon steel exposure to the atmosphere of Bogotá, based on RH, T and DSO2, was obtained.
Power generation by cheap and relatively abundant source of microbes has been investigated.
This form of renewable energy is gaining grounds in the world of energy technology. Microbial fuel
cell (MFC) technology signifies a new source for the generation of electricity from microbes found
in wastewater. The current study deals with performance of ion exchange partition and its viable
candidature in power production. The effect of operational parameters on electricity generation and
COD consumption was reported. A maximum voltage of 1.3 V was observed at 40 % H2O2 along
with wastewater from GGBL in an anode chamber. Average COD removal was more than 88%.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
Abstract
Rain is one of the main importance issues for atmospheric corrosion problem. Effects of rainfall on corrosion behaviors of carbon steels were investigated using artificial rainfall equipment. Three types of Atmospheric Corrosion Monitoring (ACM) sensors, which consist of Fe-Ag, Zn-Ag, and Al-Ag galvanic couples, were used to illustrate the correlation between the sensors output, Corrosion Rate (CR), and chemical concentration in the rain. The effects of ionic species on the corrosion behaviors were observed by using NaCl, KCl, Na2SO4, NaNO3, and KNO3 as rainfall solutions. The result revealed that the rainfall rate was insensitive to ACM sensors outputs and CRs. In contrast, the chemical species and their concentrations in the rainfall solution significantly affected the ACM outputs and CRs. The corrosivity of the cations (Na+ and K+) is negligible compared to the anions (Cl-, SO42-, NO3-).For a given number of molar concentration, the CRs resulted from the corrosivity of SO4-2anions were higher than that of Cl- and NO3- anions, respectively. According to the empirical data, the CRs is increased and then reach a steady state as the molar concentration is continuously increased. This research also indicates that the ACM sensors outputs of Fe-Ag and Zn-Ag couples are capable of estimating corrosivity of the atmosphere, while the ACM sensor of Al-Agcouple can be used to determine not only the time of wetness but also the typeofchemical species in the environment. The research methods discussed in this paper proves that the CRs are dependent on the atmospheric composition and can be forecasted through ACM sensors.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
1. The document investigates the effects of different ionic species in artificial rainfall solutions on the corrosion behavior of carbon steel.
2. Testing was conducted using an artificial rainfall chamber and three types of Atmospheric Corrosion Monitoring sensors to measure corrosion rates and sensor outputs under different conditions.
3. The results showed that the corrosion rate and sensor outputs were highly dependent on the chemical species and concentrations in the rainfall solutions. Sulfate ions caused the highest corrosion rates, followed by chloride and nitrate ions. Higher concentrations generally led to higher corrosion rates until a steady state was reached.
IRJET- Waste water treatment by Tea Waste, Alum, Pre-Aluminium ChlorideIRJET Journal
This document summarizes a study on using tea waste, alum, and pre-aluminum chloride to treat wastewater from Tighra reservoir in Gwalior, India. Heavy metals like chromium, lead, cadmium, and nickel were found in high concentrations in the reservoir water due to religious practices of immersing idols. The study collected and processed tea waste to produce an adsorbent to remove heavy metals. Testing of water samples before and after treatment showed the tea waste adsorbent was able to remove up to 25.6% of heavy metals. The results indicate tea waste has potential for wastewater treatment and removing pollutants from water bodies.
This study investigated spatial patterns of air pollution in an industrial estate in Lagos, Nigeria. Seven sampling sites were selected to measure levels of particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), hydrogen sulfide (H2S), methane (CH4), and noise. Statistical analysis using principal component analysis and cluster analysis revealed two main sources of air pollution: traffic emissions contributed most to NO2 levels, while fossil fuel combustion and industrial sources contributed most to SO2, CO, and H2S levels. The levels of SO2, NO2, and PM10 exceeded national standards at some sites, indicating traffic and industrial pollution are problems. Appropriate vehicle emission controls
Assessment of Natural Radioactivity in Soil and Water Samples from Aden Gover...paperpublications3
Abstract:The level of natural radioactivity in soils and water of 74 samples collected from locations at Aden governorate south of Yemen was measured. Concentrations of radionuclides in soils and water samples were determined by gamma-ray spectrometer using a NaI (Tl) detector with specially designed shield. The mean activity level of the natural radionuclides 226Ra, 232Th and 40K is 30.41 ±2.4, 36.26 ±2.9 and 358.12±26.54 Bq kg-1, respectively. These values are well within values reported elsewhere in the country and in other countries with similar environments. The study also examined some radiation hazard indices. The mean values obtained are, 215±37Bq kg-1, 50.10±6 nGy h-1, 0.34mSv y-1, 0.30 and 0.34 for Radium Equivalent Activity (Raeq), Absorbed Dose Rates (D), Annual Effective Dose Rates (Eff Dose), External Hazard Index (Hex) and Internal Hazard Index (Hin) respectively. All the health hazard indices are well below their recommended limits. The paper recommends further studies to estimate internal and external doses from other suspected radiological sources to the population in Aden governorate.
Keywords:Absorbed dose, south Yemen, Aden governorate, Water, Soil, Natural Radioactivity.
This document summarizes an inverse modeling study of carbonyl sulfide (COS) using the TM5-4DVAR model. The objectives were to 1) implement an inverse system for COS, carbon disulfide (CS2), and dimethyl sulfide (DMS), 2) invert COS based on closing global budgets, and 3) validate the model with independent HIPPO and aircraft profile data. The results showed missing COS emissions in the tropics and additional sinks at high latitudes in the Northern Hemisphere. Assimilating both NOAA and HIPPO data into the model improved agreement with independent validation data compared to using NOAA data alone. Future work will include assimilating satellite observations
This document presents the results of a systematic study measuring indoor radon concentration levels across the main urban areas of Cyprus. Between 2004-2012, over 400 measurements were taken using portable detectors in the districts of Lefkosia, Lemesos, Larnaka, and Pafos, which are home to 67.3% of Cyprus' population. The districts were divided into 189 grid cells of 1 km2 each. Grid cell mean radon concentrations ranged from 1.7 to 86.4 Bq/m3, with an overall mean of 14.3 Bq/m3. This is lower than the estimated global average of 39 Bq/m3. Equivalent annual effective dose rates were also calculated and
Assessment of the Environmental Impact of Landfill Sites in the East Riding o...Mark Kwabena Gadogbe
This document summarizes a study that used GIS spatial analysis and multi-criteria evaluation to identify areas in the East Riding of Yorkshire, UK that are most sensitive to environmental impacts from landfill leachate and to identify the three landfill sites that pose the highest risk. The methodology weighted factors like proximity to residential areas, protected sites, and water sources to produce a sensitivity map. The analysis found 11 high-risk landfill sites, and identified Carnaby (Moor Lane), Gransmoor Quarry Site A, and Thorneholme as having the highest pollution potential due to size, waste types, and nearby water sources and boreholes.
Elemental Analysis of Soil samples of Cox’s Bazar Sea-Beach Area Using PIXE ...AM Publications
This document summarizes an elemental analysis of soil samples from Cox's Bazar, Bangladesh using the PIXE technique. Soil samples were collected from different distances from the sea and analyzed using a proton beam. Notably high concentrations of tantalum were found in samples near sea water compared to other elements. Samples from cultivated areas contained high levels of tantalum, potassium, and calcium. The sample from a populated area showed high concentrations of iron, silicon, and rubidium. The data on elemental compositions can help assess environmental conditions and risks to human and ecological health in the area.
SIMULATION OF ATMOSPHERIC POLLUTANTS DISPERSION IN AN URBAN ENVIRONMENTAM Publications
Interest in air pollution investigation of urban environment due to existence of industrial and commercial activities along with vehicular emission and existence of buildings and streets which setup natural barrier for pollutant dispersion in the urban environment has increased. The air pollution modelling is a multidisciplinary subject when the entire cities are taken under consideration where urban planning and geometries are complex which needs a large software packages to be developed like Operational Street Pollution Model (OSPM), California Line Source model (CALINE series) etc. On overviewing various works it can be summarized that the air pollutant dispersion in urban street canyons and all linked phenomenon such as wind flow, pollutant concentrations, temperature distribution etc. generally depend on wind speed and direction, building heights and density, road width, source and intensity of air pollution, meteorological variables like temperature, humidity etc. A unique and surprising case is observed every time on numerous combinations of these factors. The main aim of this study is to simulate the atmospheric pollutant dispersion for given pollutant like carbon monoxide, sulphur dioxide and nitrogen dioxide and given atmospheric conditions like wind speed and direction. Computational Fluid Dynamics (CFD) simulation for analysing the atmospheric pollutant dispersion is done after natural airflow analysis. Volume rendering is done for variables such as phase 2 volume fraction and velocity with resolution as 250 pixels per inch and transparency as 20%. It can be observed that all the three pollutant namely nitrogen dioxide, sulphur dioxide and carbon monoxide the phase 2 volume fraction changes from 0 to 1. The wind velocity changes from 3.395×10-13 m/s to 1.692×102 m/s. The dispersion of pollutants follow the sequence Sulphur dioxide>Carbon monoxide>Nitrogen dioxide.
IRJET- Analysis of Sediment Contamination of Deepor Beel, Guwahati, Assam, IndiaIRJET Journal
This document analyzes sediment contamination in Deepor Beel Lake located in Guwahati, Assam, India. Six students and one professor collected sediment samples from four locations around the lake on a monthly basis and analyzed physical and chemical parameters including pH, heavy metals, etc. Their analysis found pollution levels and heavy metal concentrations in sediments varied between locations and over time, with highest levels near waste dumping sites. The study suggests sediment contamination poses a threat to local groundwater and highlights the need for preventive measures to protect the lake's water quality.
This document summarizes a study that used portable X-ray fluorescence spectrometry (XRF) to rapidly detect toxic metals like lead in non-crushed oyster shells. The researchers developed a methodology to use a portable XRF to simultaneously detect multiple elements in oyster shells without crushing them. Lead contamination was confirmed in contaminated oyster shells using both XRF and scanning electron microscopy with energy dispersive spectroscopy (SEMeEDS). The portable XRF provided a quick, non-destructive, and cost-effective way to assess lead contamination in oyster shells.
President Obama announced a new climate plan that includes setting limits on carbon emissions from US power plants. The plan aims to reduce emissions from fossil fuel energy sources and increase renewable energy and energy efficiency. Researchers from the Atmospheric Sciences Research Center at SUNY and Rensselaer Polytechnic Institute studied the catalytic reactivity of airborne particulate matter and its potential role in atmospheric chemical reactions. Their research examined particles collected from power plant boilers and simulated samples to assess the impact of heterogeneous catalysis on the rates of pollutant gases in the atmosphere.
Study and analysis of the concentrations of tropospheric ozone in the city of...Enrique Posada
The document analyzes data from 9 air quality monitoring stations in Medellin, Colombia between 2014-2015. It finds:
- The average hourly ozone concentration was 15.7 ppb, with only 1.29% of readings exceeding the standard of 61 ppb.
- Concentrations were highest in southern stations and lowest in northern stations, peaking between 11am-3pm daily.
- Concentrations correlated with sunlight and were higher further from the river and in more urban areas.
- The situation was not considered serious from a public health perspective but deserves continued monitoring.
LGC is addressing the UK's chemical and bio-measurement needs to support key industries like healthcare, food, and energy. LGC researchers are developing new methods to accurately measure pollutants like PBDEs in water samples to help enforce the EU Water Framework Directive and clean up rivers and lakes. They are also studying microbial communities as bioindicators of water quality to rapidly assess the impacts of pollution and help mitigate threats to water resources.
This document is a summary for policymakers from the Working Group I contribution to the IPCC Fourth Assessment Report. It describes the key findings regarding human and natural drivers of climate change based on improved data, analyses, and understanding since the Third Assessment Report. The summary highlights that atmospheric concentrations of greenhouse gases like carbon dioxide, methane and nitrous oxide have increased significantly due to human activities since 1750 and now far exceed pre-industrial levels. It also notes that human activities have very likely caused warming of the climate system through radiative forcings, with a best estimate of +1.6 W/m2 net forcing since 1750. Direct observations show warming of the atmosphere and ocean, shrinking glaciers and ice sheets, rising
This document provides a literature review on the use of nanoparticles for removing contaminants from wastewater. It discusses nanoparticles that have been used to remove various types of contaminants including metals, non-metals, organic and inorganic pollutants, and microorganisms. The document surveys research on nanoparticles for removing specific contaminants such as heavy metals, pesticides, mercury, and pathogenic bacteria. It also examines factors that influence contaminant removal like nanoparticle size, surface chemistry, adsorption properties, and reusability. The literature demonstrates that nanoparticles show potential for wastewater treatment due to their large surface area and chemical reactivity.
2013 Global Carbon Budget (Global Carbon Project)Future Earth
The Global Carbon Project's 2013 global carbon budget.
Published 19 November 2013.
See website for more information
http://www.globalcarbonproject.org/carbonbudget/index.htm
The Global Carbon Project (GCP) is a project of the International Geosphere-Biosphere Programme. GCP's chair Corinne Le Quéré is a member of the Future Earth scientific committee.
The Efficiency of Eicchornia crassipes in the Phytoremediation of Waste Water...iosrjce
The study involved a laboratory experiment on the use of Eicchornia crassipes in the
phytoremediation of a stream polluted by waste water from Kaduna Refinery and Petrochemical Company. The
physiochemical characteristics of the waste water were determined before and after the treatment. The
experiment lasted for three weeks and the rate of reduction was recorded. The highest rate of mean reduction
were for heavy metals accounting 99.0%, 95.0%, 96.3%, 100%, 99.3% and 94.3% of Cd, Hg, Zn, Mn, Pb and
Ag respectively. Other physiochemical parameters include Total Dissolved Solids (TDS) 90%, Chemical Oxygen
Demand (COD) 54.3%, Nitrate 86.3%, Biochemical Oxygen demand (BOD) 13.7%, Conductivity 11%, Total
suspended Solids (TSS) 55.7%, Turbidity 18%, 87% Total Solids (TS) and the pH 4%. Ecchornia crassipes is a
suitable candidate for effective phytoremediation of water from Romi stream.
This document discusses using liquid carbon dioxide as an alternative to water for hydraulic fracturing in shale gas extraction in India. The objective is enhanced gas recovery from Indian shales while sequestering the greenhouse gas carbon dioxide. Methods suggested include flooding experiments to model methane desorption and carbon dioxide adsorption capacities of Indian shale basins based on their total organic content. Previous works demonstrated that organic matter preferentially adsorbs carbon dioxide over methane, and that imaging techniques can provide insights into shale microstructure and flow properties. The conclusion is that using carbon dioxide for fracturing and sequestration could make shale gas extraction more sustainable while providing economic storage of carbon dioxide.
Annual atmospheric corrosion rate and dose-response function for carbon steel...Carlos Arroyave
This paper presents an assessment on the behavior of plain carbon steel exposure to the atmosphere of Bogotá. The main climate and environmental parameters, including relative humidity (RH), temperature (T), sulphur dioxide deposition (DSO2) and particulate matter deposition (DPM) were measured. Furthermore, mass loss of AISI/SAE 1006 plain carbon steel coupons was measured along one year. In this case, coupons were exposed in eight test sites located across the city of Bogotá. Results show that the corrosion rate of carbon steel is less than 35 μm yr–1 after one year. It was found that the west part of the city has the greatest aggressivity, which has the highest levels of DPM and DSO2, related with the characteristics of the anthropogenic activities distribution across the city. A dose-response function of plain carbon steel exposure to the atmosphere of Bogotá, based on RH, T and DSO2, was obtained.
Power generation by cheap and relatively abundant source of microbes has been investigated.
This form of renewable energy is gaining grounds in the world of energy technology. Microbial fuel
cell (MFC) technology signifies a new source for the generation of electricity from microbes found
in wastewater. The current study deals with performance of ion exchange partition and its viable
candidature in power production. The effect of operational parameters on electricity generation and
COD consumption was reported. A maximum voltage of 1.3 V was observed at 40 % H2O2 along
with wastewater from GGBL in an anode chamber. Average COD removal was more than 88%.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
Abstract
Rain is one of the main importance issues for atmospheric corrosion problem. Effects of rainfall on corrosion behaviors of carbon steels were investigated using artificial rainfall equipment. Three types of Atmospheric Corrosion Monitoring (ACM) sensors, which consist of Fe-Ag, Zn-Ag, and Al-Ag galvanic couples, were used to illustrate the correlation between the sensors output, Corrosion Rate (CR), and chemical concentration in the rain. The effects of ionic species on the corrosion behaviors were observed by using NaCl, KCl, Na2SO4, NaNO3, and KNO3 as rainfall solutions. The result revealed that the rainfall rate was insensitive to ACM sensors outputs and CRs. In contrast, the chemical species and their concentrations in the rainfall solution significantly affected the ACM outputs and CRs. The corrosivity of the cations (Na+ and K+) is negligible compared to the anions (Cl-, SO42-, NO3-).For a given number of molar concentration, the CRs resulted from the corrosivity of SO4-2anions were higher than that of Cl- and NO3- anions, respectively. According to the empirical data, the CRs is increased and then reach a steady state as the molar concentration is continuously increased. This research also indicates that the ACM sensors outputs of Fe-Ag and Zn-Ag couples are capable of estimating corrosivity of the atmosphere, while the ACM sensor of Al-Agcouple can be used to determine not only the time of wetness but also the typeofchemical species in the environment. The research methods discussed in this paper proves that the CRs are dependent on the atmospheric composition and can be forecasted through ACM sensors.
Effects of anion on the corrosion behaviors of carbon steel under artificial ...eSAT Journals
1. The document investigates the effects of different ionic species in artificial rainfall solutions on the corrosion behavior of carbon steel.
2. Testing was conducted using an artificial rainfall chamber and three types of Atmospheric Corrosion Monitoring sensors to measure corrosion rates and sensor outputs under different conditions.
3. The results showed that the corrosion rate and sensor outputs were highly dependent on the chemical species and concentrations in the rainfall solutions. Sulfate ions caused the highest corrosion rates, followed by chloride and nitrate ions. Higher concentrations generally led to higher corrosion rates until a steady state was reached.
Natural radiation levels and health hazard indices of soil in Owerri Nigeriatheijes
The document summarizes a study that measured natural radiation levels and calculated health hazard indices in soil samples from three local government areas in Owerri, Nigeria.
The mean activity concentrations of 40K, 226Ra and 232Th were 167.2 ± 10.5 Bq/kg, 19.7 ± 1.9 Bq/kg and 18.1 ± 3.3 Bq/kg respectively. The radium equivalent activity was 58.5 Bq/kg, the absorbed dose rate was 27.1 nGy/h, and the annual effective dose was 132.78 μSv. The external and internal health hazard indices were 0.16 and 0.21, respectively, which are below permissible
Evaluation of Radiation Hazard Indices and Excess Lifetime Cancer Risk Due To...IOSR Journals
This document evaluates the radiation hazard indices and excess lifetime cancer risk from natural radioactivity in mined tailings from 14 locations in Jos Plateau State, Nigeria. Samples were analyzed using gamma spectroscopy and the average concentrations of Ra226, Th232 and K40 were found to be far above world averages. Various hazard indices like annual gonadal equivalent dose, radium equivalent, external hazard index, internal hazard index, representative gamma index, annual effective dose equivalent (outdoor and indoor) and excess lifetime cancer risk were calculated. The values obtained were far above world recommended levels, indicating significant health hazards for miners, processors and nearby residents from radiation exposure. The results show the need to investigate radiation levels in other environmental samples from the area like
Radioactivity exposure level from some mining sites in Wurno LGA, Sokoto have been determined in this paper. The inhabitant’s exposure rates were found through in-situ radiation measurement and liquid scintillation counting of water samples. An invented equation for sampling was used to spot out points. Measurement was done with Digilert-50 at Gonadal height from 15 points. Three closed points were averaged to 5 points between; Kandam, Gyalgyal, Burmawan Masaka, Dinbiso and Giyawa mining sites respectively. Water samples were collected for Hidex 300 liquid scintillation counting of gross alpha and beta radioactivity. The mean in-situ radiation results were 0.206, 0.317, 0.108, 0.335 and 0.230 for the sample points. Annual effective dose and cancer risk were found in range of 0.32542 - 0.411125 and 5.01×10-1 - 1.56×101 respectively. These values were found significantly higher than the WHO and ICRP levels. Dangers from ransacking the major rocks that harbors these nuclides may be more prominent. These trends should be curtailed by authorities to avert future menace of environmental and health maladies.
Estimation of soil hazard quotient of some identified heavy metals from an ab...Alexander Decker
This document summarizes a study that analyzed soil samples from an abandoned waste disposal site in Aba, Nigeria that had been reclaimed for commercial use. Heavy metal concentrations of chromium, cobalt, copper, zinc, and lead were measured in 20 soil samples using an Energy Dispersive X-ray Fluorescence Spectrometer. The results found heavy metal concentrations that far exceeded international standards and natural background levels, indicating significant pollution from disposed waste. All identified heavy metals had hazard quotients much greater than 1, suggesting health risks to people using the site. The study recommends remediation like adjusting soil pH and drainage to reduce heavy metal toxicity and make the area safer for human use.
IRJET- A Novel Detection Technique for Nuclear Radiations: Solid State Nuclea...IRJET Journal
This document reviews the use of solid state nuclear track detector CR-39 for detecting nuclear radiations. CR-39 is a plastic that is highly sensitive to charged particles like alpha particles and protons. When these particles pass through the plastic, they leave latent damage tracks that can be chemically etched to become visible. The document discusses how CR-39 has been used to detect products of nuclear fusion reactions and measure radon concentrations. It also examines different etching methods and conditions that allow tracks to be enlarged and counted more easily. CR-39 provides a simple, robust, and inexpensive way to detect ionizing radiation and has various applications in fields like health physics and fusion research.
Application of radiometric surveys to delineate between sedimentary terrain a...Alexander Decker
Th(Bq/kg)
K(Bq/kg)
1) The study used a NaI(TI) detector and multichannel analyzer to analyze soil samples from sedimentary and basement terrains in Nigeria to determine activity concentrations of radium, thorium, and potassium.
2) The results found higher average activity concentrations of radium, thorium, and potassium in the basement complex compared to the sedimentary terrain. Specifically, the averages were 44 Bq/kg, 53 Bq/kg, 80 Bq/kg for the basement complex and 35 Bq/kg, 43 Bq/kg, 72 Bq/kg for the sedimentary terrain.
3)
The document investigates the exposure of drillers to natural radioactivity in Abuja, Nigeria. Rock samples were collected from two borehole sites at different depths and layers. Neutron activation analysis was used to determine the concentrations of radioactive elements like uranium and thorium in the samples. The results showed elevated levels of uranium and thorium above global averages, posing potential health risks to drillers if exposed over long periods without protection. The study concludes drillers should be aware of subsurface geology and take necessary precautions when drilling to avoid overexposure to radiation.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Detection of the Presence of Heavy Metal Pollutants in Eleme Industrial Area ...theijes
The presenceof some heavy metal pollutants which are deposited on soil in the Eleme environment due to the operational activities of some companies in the area have been studied. Some soil samples in areas situated around industrial installations were collected and analyzed using Atomic Absorption Spectrophotometer (AAS). Results obtained show the presence and concentration distributions of nine heavy metals. The metals are Iron (Fe), Manganese (Mn), Zinc (Zn), Lead (Pb), Copper (Cu), Chromium (Cr), Cobalt (Co) and Cadmium (Cd). It was observed that over 90% of each of the metals was located in communities hosting the industrial corporations while the remaining 10% is distributed to areas away from the source or host communities. This reveals that, a link exists between the pollutants and the activities of these industries.
Assessment of Heavy Metals Content in Surface and Sub Surface Soil Samples in...IRJET Journal
The study assessed heavy metal content in surface and subsurface soil samples from waste dumpsites in Guntur, Andhra Pradesh, India. Samples were collected from 5 dumpsites at depths of 0-15cm and 15-30cm. Analysis found higher concentrations of iron, zinc, lead, cadmium, nickel, copper, and chromium in surface soils compared to subsurface soils. Mean metal levels generally exceeded Indian standards. This indicates percolation of heavy metals into subsurface soils poses risks of groundwater contamination. There is no proper solid waste management in the area.
An Analytical Review on Radioactive Waste ClassificationIRJET Journal
This document discusses the classification and management of radioactive waste from nuclear power generation. It begins by reviewing the history of nuclear technology and discovery of radioactive materials. It then discusses the different categories of radioactive waste - exempt, very short-lived, very low-level, low-level, intermediate-level, and high-level - based on their radioactivity and appropriate disposal methods. Experimental measurements of radiation exposure near a waste disposal site in Nigeria are presented. Statistics on estimated radioactive waste generation amounts and per reactor among different countries are provided. The rare element Protactinium is briefly outlined. The conclusion advocates for minimization of waste and improved storage methods such as pitted structures to isolate heat from high-level waste.
Enrichment Factor and Geo-accumulation Index for Heavy Metals at Industrial Z...iosrjce
This field study was conducted in Al Anbar Province in Iraq in order to identify the level of
contamination inlarge industrial zones, 8samples soil had been collected with depth (0-2)cm, were analyzed by
X-ray Fluorescence for 6 metals (Pb, Ni, Cd, Co, Cr, Cu ).calculated Enrichment Factor and Geo-accumulation
Index to assess quantitatively the influences of human activities by these heavy metals.
Catalytic Decomposition of N2O: Best Achievable Methods and Processesdrboon
In the current review paper, the N2O direct decomposition was investigated over a series of different catalytic systems, containing metals, zeolites, cobalt spinels. The N2O split via catalysis and the use of membrane systems in the separation to molecules N2 and O2 were studied, too. Decomposition of N2O has been studied in the temperature rate of 673 to 873 K over supported catalysts of chemical elements: Pd, Rh, Ru, Ni, Pt, Zn, Fe, Cu, Ir, over γ- Al2O3 showing their best catalytic activity. M-zeolites, (M = Cu, Fe, Co, etc.) supported on perovskite or precious metals such as Pd, Rh zeolites and dominant iron and copper catalytic structures such as ZSM-5, MFI, BEA, BETA investigated in the temperature rate of 583 to 775 K with best catalytic activity. Iron zeolites are more prevalent at high concentrations showing good catalytic behavior only at high temperatures. The spinel catalyst Zn0.36Co0.64Co2O4 and Rh/Mullite catalyst offer up to complete N2O conversion.
Physicochemical Analysis, Heavy Metals Contaminants and Health Risks Assessme...PriyankaKilaniya
The increasing exposure of humans to Harmattan dust is becoming a growing concern, especially in Northern Nigeria. This study aimed to identify the heavy metal contaminants, assess the associated health risks, and evaluate the physicochemical properties of the Harmattan dust. During the sample collection period, which took place from December 2023 to February 2024, Harmattan dust samples were collected from 20 different locations, 4.5 cm above the ground, using cleaned Petri dishes. The composite samples from each month were analyzed using standard analytical techniques and AAS to examine the physicochemical properties and heavy metal contamination, respectively. The results of the physicochemical examination, which included pH, organic matter, organic carbon, electrical conductivity, and moisture content, showed a significant difference (p ≥ 0.05), using statistical tools. However, there was no significant difference in the concentration of heavy metals such as pb, Cd, Ni, Zn, Cu, and Cr among the samples collected in December, January, and February. The concentration of pb and Ni was high in December and January, at 78 mg/kg and 73 mg/kg, respectively, while Ni was at 108 mg/kg and 80 mg/kg for December and January, respectively. The health risk assessment, using the model developed by EPA for children and adults, showed that Cu, Ni, and pb had a hazard index of 1.305, 1.098, and 1.205, and 1.050, respectively. Therefore, Cu and Ni pose health risks for children, while pb poses health risks for both children and adults. Protective measures, such as face masks, during the Harmattan period may help protect people from direct exposure to these heavy metals.
Radioactive waste is an arising concern in present era because of increasing nuclear activities and nuclear weapon activities related to defence. It is a significant problem to handle and protect the environment for safeguarding future generations. This study deals with the global problem of radioactive waste problems and its management. It consists of various aspects related to radioactive waste and also, caters to the cause of concern, effects of radioactive waste, classification and approaches of radioactive waste, involvement of waste magnitudes and prospective solutions, disposal of radioactivity and its management. With increasing nuclear power and arsenal, it is important to monitor and immobilize the waste and safe respositories deposition.
Enhancement on radon adsorption property of gac using nano size carbon colloidsAlexander Decker
This document summarizes a study that aimed to enhance the radon removal efficiency of granular activated carbon (GAC) using nano-sized carbon colloids (NCC). NCC was produced through a simple electrolysis method and used to impregnate GAC. Testing found that the NCC-impregnated GAC was able to adsorb 1.3-2 times more radon gas than untreated GAC, despite having a smaller total surface area. It is believed the NCC filled mesopores, creating more micropores suitable for radon adsorption. The study concludes that NCC impregnation improves GAC's effectiveness at radon removal.
Similar to Risk assessment of abandoned radioactive logging sources in oil wells in nigeria (20)
Abnormalities of hormones and inflammatory cytokines in women affected with p...Alexander Decker
Women with polycystic ovary syndrome (PCOS) have elevated levels of hormones like luteinizing hormone and testosterone, as well as higher levels of insulin and insulin resistance compared to healthy women. They also have increased levels of inflammatory markers like C-reactive protein, interleukin-6, and leptin. This study found these abnormalities in the hormones and inflammatory cytokines of women with PCOS ages 23-40, indicating that hormone imbalances associated with insulin resistance and elevated inflammatory markers may worsen infertility in women with PCOS.
A usability evaluation framework for b2 c e commerce websitesAlexander Decker
This document presents a framework for evaluating the usability of B2C e-commerce websites. It involves user testing methods like usability testing and interviews to identify usability problems in areas like navigation, design, purchasing processes, and customer service. The framework specifies goals for the evaluation, determines which website aspects to evaluate, and identifies target users. It then describes collecting data through user testing and analyzing the results to identify usability problems and suggest improvements.
A universal model for managing the marketing executives in nigerian banksAlexander Decker
This document discusses a study that aimed to synthesize motivation theories into a universal model for managing marketing executives in Nigerian banks. The study was guided by Maslow and McGregor's theories. A sample of 303 marketing executives was used. The results showed that managers will be most effective at motivating marketing executives if they consider individual needs and create challenging but attainable goals. The emerged model suggests managers should provide job satisfaction by tailoring assignments to abilities and monitoring performance with feedback. This addresses confusion faced by Nigerian bank managers in determining effective motivation strategies.
A unique common fixed point theorems in generalized dAlexander Decker
This document presents definitions and properties related to generalized D*-metric spaces and establishes some common fixed point theorems for contractive type mappings in these spaces. It begins by introducing D*-metric spaces and generalized D*-metric spaces, defines concepts like convergence and Cauchy sequences. It presents lemmas showing the uniqueness of limits in these spaces and the equivalence of different definitions of convergence. The goal of the paper is then stated as obtaining a unique common fixed point theorem for generalized D*-metric spaces.
A trends of salmonella and antibiotic resistanceAlexander Decker
This document provides a review of trends in Salmonella and antibiotic resistance. It begins with an introduction to Salmonella as a facultative anaerobe that causes nontyphoidal salmonellosis. The emergence of antimicrobial-resistant Salmonella is then discussed. The document proceeds to cover the historical perspective and classification of Salmonella, definitions of antimicrobials and antibiotic resistance, and mechanisms of antibiotic resistance in Salmonella including modification or destruction of antimicrobial agents, efflux pumps, modification of antibiotic targets, and decreased membrane permeability. Specific resistance mechanisms are discussed for several classes of antimicrobials.
A transformational generative approach towards understanding al-istifhamAlexander Decker
This document discusses a transformational-generative approach to understanding Al-Istifham, which refers to interrogative sentences in Arabic. It begins with an introduction to the origin and development of Arabic grammar. The paper then explains the theoretical framework of transformational-generative grammar that is used. Basic linguistic concepts and terms related to Arabic grammar are defined. The document analyzes how interrogative sentences in Arabic can be derived and transformed via tools from transformational-generative grammar, categorizing Al-Istifham into linguistic and literary questions.
A time series analysis of the determinants of savings in namibiaAlexander Decker
This document summarizes a study on the determinants of savings in Namibia from 1991 to 2012. It reviews previous literature on savings determinants in developing countries. The study uses time series analysis including unit root tests, cointegration, and error correction models to analyze the relationship between savings and variables like income, inflation, population growth, deposit rates, and financial deepening in Namibia. The results found inflation and income have a positive impact on savings, while population growth negatively impacts savings. Deposit rates and financial deepening were found to have no significant impact. The study reinforces previous work and emphasizes the importance of improving income levels to achieve higher savings rates in Namibia.
A therapy for physical and mental fitness of school childrenAlexander Decker
This document summarizes a study on the importance of exercise in maintaining physical and mental fitness for school children. It discusses how physical and mental fitness are developed through participation in regular physical exercises and cannot be achieved solely through classroom learning. The document outlines different types and components of fitness and argues that developing fitness should be a key objective of education systems. It recommends that schools ensure pupils engage in graded physical activities and exercises to support their overall development.
A theory of efficiency for managing the marketing executives in nigerian banksAlexander Decker
This document summarizes a study examining efficiency in managing marketing executives in Nigerian banks. The study was examined through the lenses of Kaizen theory (continuous improvement) and efficiency theory. A survey of 303 marketing executives from Nigerian banks found that management plays a key role in identifying and implementing efficiency improvements. The document recommends adopting a "3H grand strategy" to improve the heads, hearts, and hands of management and marketing executives by enhancing their knowledge, attitudes, and tools.
This document discusses evaluating the link budget for effective 900MHz GSM communication. It describes the basic parameters needed for a high-level link budget calculation, including transmitter power, antenna gains, path loss, and propagation models. Common propagation models for 900MHz that are described include Okumura model for urban areas and Hata model for urban, suburban, and open areas. Rain attenuation is also incorporated using the updated ITU model to improve communication during rainfall.
A synthetic review of contraceptive supplies in punjabAlexander Decker
This document discusses contraceptive use in Punjab, Pakistan. It begins by providing background on the benefits of family planning and contraceptive use for maternal and child health. It then analyzes contraceptive commodity data from Punjab, finding that use is still low despite efforts to improve access. The document concludes by emphasizing the need for strategies to bridge gaps and meet the unmet need for effective and affordable contraceptive methods and supplies in Punjab in order to improve health outcomes.
A synthesis of taylor’s and fayol’s management approaches for managing market...Alexander Decker
1) The document discusses synthesizing Taylor's scientific management approach and Fayol's process management approach to identify an effective way to manage marketing executives in Nigerian banks.
2) It reviews Taylor's emphasis on efficiency and breaking tasks into small parts, and Fayol's focus on developing general management principles.
3) The study administered a survey to 303 marketing executives in Nigerian banks to test if combining elements of Taylor and Fayol's approaches would help manage their performance through clear roles, accountability, and motivation. Statistical analysis supported combining the two approaches.
A survey paper on sequence pattern mining with incrementalAlexander Decker
This document summarizes four algorithms for sequential pattern mining: GSP, ISM, FreeSpan, and PrefixSpan. GSP is an Apriori-based algorithm that incorporates time constraints. ISM extends SPADE to incrementally update patterns after database changes. FreeSpan uses frequent items to recursively project databases and grow subsequences. PrefixSpan also uses projection but claims to not require candidate generation. It recursively projects databases based on short prefix patterns. The document concludes by stating the goal was to find an efficient scheme for extracting sequential patterns from transactional datasets.
A survey on live virtual machine migrations and its techniquesAlexander Decker
This document summarizes several techniques for live virtual machine migration in cloud computing. It discusses works that have proposed affinity-aware migration models to improve resource utilization, energy efficient migration approaches using storage migration and live VM migration, and a dynamic consolidation technique using migration control to avoid unnecessary migrations. The document also summarizes works that have designed methods to minimize migration downtime and network traffic, proposed a resource reservation framework for efficient migration of multiple VMs, and addressed real-time issues in live migration. Finally, it provides a table summarizing the techniques, tools used, and potential future work or gaps identified for each discussed work.
A survey on data mining and analysis in hadoop and mongo dbAlexander Decker
This document discusses data mining of big data using Hadoop and MongoDB. It provides an overview of Hadoop and MongoDB and their uses in big data analysis. Specifically, it proposes using Hadoop for distributed processing and MongoDB for data storage and input. The document reviews several related works that discuss big data analysis using these tools, as well as their capabilities for scalable data storage and mining. It aims to improve computational time and fault tolerance for big data analysis by mining data stored in Hadoop using MongoDB and MapReduce.
1. The document discusses several challenges for integrating media with cloud computing including media content convergence, scalability and expandability, finding appropriate applications, and reliability.
2. Media content convergence challenges include dealing with the heterogeneity of media types, services, networks, devices, and quality of service requirements as well as integrating technologies used by media providers and consumers.
3. Scalability and expandability challenges involve adapting to the increasing volume of media content and being able to support new media formats and outlets over time.
This document surveys trust architectures that leverage provenance in wireless sensor networks. It begins with background on provenance, which refers to the documented history or derivation of data. Provenance can be used to assess trust by providing metadata about how data was processed. The document then discusses challenges for using provenance to establish trust in wireless sensor networks, which have constraints on energy and computation. Finally, it provides background on trust, which is the subjective probability that a node will behave dependably. Trust architectures need to be lightweight to account for the constraints of wireless sensor networks.
This document discusses private equity investments in Kenya. It provides background on private equity and discusses trends in various regions. The objectives of the study discussed are to establish the extent of private equity adoption in Kenya, identify common forms of private equity utilized, and determine typical exit strategies. Private equity can involve venture capital, leveraged buyouts, or mezzanine financing. Exits allow recycling of capital into new opportunities. The document provides context on private equity globally and in developing markets like Africa to frame the goals of the study.
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Risk assessment of abandoned radioactive logging sources in oil wells in nigeria
1. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
Risk Assessment of Abandoned Radioactive Logging Sources in
Oil Wells in Nigeria
Mr. Amidu, Muritala Alade1*, Mr. Appah Thompson1, Prof. Adewale Dosunmu2
1. Centre for Nuclear Energy Studies (CNES), University of Port Harcourt, P.M.B 5323, Port Harcourt, Nigeria.
2. Department of Petroleum Engineering, University of Port Harcourt, P.M.B 5323, Port Harcourt, Nigeria
*
Email address of the corresponding author: murhylimatsad@gmail.com
appahtompson@yahoo.com,adewale.dosunmu@gmail.com
The M.Eng programme that culminated in this research work was facilitated and sponsored by Nigeria Atomic
Energy Commission (NAEC).
Abstract
An integrated model for the risk assessment is developed for abandoned radioactive logging sources (Am-241
and Cs-137) in oil wells. The model is composed of four components: Source term, Barrier failure model, a
geosphere model, a biosphere model, and finally a dose and health effect model to analyse the radionuclide
dispersion phenomenon from the abandoned source term to the risk of serious health effects on members of the
public (cancer death). In addition to time-dependent annual release rate and dose rate for each radionuclide, the
ultimate risk in terms of cancer death rate is estimated. The results show that the highest value of the annual
dose for the abandoned radioactive logging sources is less than the individual dose limit to the human body, and
the calculated highest cancer death rate is much lower than that of background radiation but higher than that of
low-level waste repository. Subsequently, an abandonment procedure was developed in an effort to manage the
risk and reduce it to the barest minimum. It is concluded that the use of simplified mathematical modelling for
the risk assessment of abandoned radioactive sources in oil wells could be an effective tool for development of
efficient and acceptable abandonment procedure.
Keywords: risk assessment, geosphere model, dose, cancer death, logging sources, low-level repository,
radionuclide, abandonment procedure
1. Introduction
The average number of radioactive sources abandoned in oil wells in Nigeria between 2001 and 2007 is greater
than the worldwide average. Most of these radioactive sources are high risk with considerable long half lives
which can pose danger to human health and the environment. In general these radioactive sources were
abandoned deep in the ground as a result of well logging activities. The nature of the containment as well as the
location of the abandonment is such that, radionuclide release to the environment could occur after a period of
time thereby contaminating the environment.
Worldwide data on abandoned radioactive sources were available for 18 years. Data on loss of control of
radioactive sources in oil wells which pose the threat of actual or potential release of radioactive materials to the
environment were obtained from IAEA TECDOCS 588(1991), 1105(1999) and 1242(2001) as compiled by
Bello (2007). The reported cases of abandonment of radioactive sources in some of the oil producing countries
between 1983 and 2001 are shown in Fig 1 with USA having the highest number of cases.
There is no data on stuck and abandoned radioactive sources in oil wells in Nigeria prior to 2001. The respective
numbers of abandonment of radioactive sources in wells by well-owners are depicted by Fig 2.
Since 2001, there has been at least one recorded case of abandonment of radioactive sources in oil wells in
Nigeria. The highest numbers of reported cases were obtained in 2006 and this called for concern by both the
well owners and the regulatory authority. The numbers of reported cases of radioactive sources abandonment in
Nigeria for every year from 2001 to 2007 are clearly shown in Fig 3.
Among the radioactive sources abandoned in Nigeria (2001-2007) there were 17 Cs-137 (30yrs) and 17 Am-Be
(433yrs). Therefore, number of incidents recorded in Nigeria between 2001 and 2007 (6 years) is greater than the
worldwide average as shown in Fig 4
16
2. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
Reported Cases of Abandonment of Radioactive Sources
World Wide: 1983-2001
Number of Cases
120
104
100
80
60
40
20
1
3
2
6
5
3
15
8
0
Country
Fig 1: Reported Cases of Abandoned Radioactive Sources World Wide
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
4
4
3
P
ea
k
A
dd
ax
P
et
ro
le
um
2
E
lf
S
P
D
C
2
C
h
ev
ro
n
2
E
xx
on
M
ob
il
N.o Aa d n e t
o f b n o m ns
No. of Abandonm e nts Vs We ll Ow ne r s :2001-2007
Well Ow ner
Fig 2: Number of Abandoned Radioactive Sources by Well Owners in Nigeria
17
3. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
Reported Cases of Abandonment of Radioactive Sources in
Nigeria: 2001-2007
7
6
No. of Cases
6
5
4
4
4
3
2
1
1
1
1
2004
2005
0
0
2001
2002
2003
2006
2007
Year Of Abandonment
Fig 3: Reported Cases of Abandoned Sources in Nigeria over the Years
Reported Cases of Abandonment of Radioactive Sources: Worldwide
Average Vs Nigeria
17.2
17
No. of Cases
17
16.8
16.6
16.4
16.2
16
16
15.8
15.6
15.4
World Wide Av.
Nigeria
Fig 4: Comparison of Average Number of Abandoned Sources in Nigeria with World Wide Average
2. Description of Hypothetical Source Abandonment Site
The hypothetical logging source abandonment site considered in this study is a typical bottom hole source
abandonment containing Caesium (137Cs) and Americium-Beryllium (241Am-Be) sources which is illustrated in
Fig. 5
18
4. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
Fig 5: Schematic Diagram of a Multi-Barrier System for Radioactive Sources Abandonment in Oil Wells
The 137Cs is contained in glass or ceramic matrix before being doubly encapsulated with carbon steel while
241
Am-Be is a mixture of Americium oxide powder and Beryllium oxide powder contained in a pressurized
carbon steel container. The multi-barrier system includes the engineered barriers such as the cement plug and the
source container. The natural barrier is the undisturbed geological formation between the abandoned logging
source and the biosphere.
3. Models and Calculation
3.1 Abandoned Logging Source Term Model
The most common chemical sources used in petrophysical measurements are 137Cs (Caesium) which provides
gamma rays used in formation density logging and a mixture of 241Am (Americium) and Be (Beryllium) which
provides neutrons for neutron porosity logging.
From the half-life and the initial activity, the time dependent activity, ( ), of the radioactive nuclide is
obtained:
( )=
1
Where
is the initial activity, and is the decay constant of nuclide . The half-life and initial activity for
relevant radionuclide are given in Table 1
Table 1: Relevant Radionuclide Used in Neutron-Density Logging Tool
Nuclide
Half-life (yr)
Initial Activity (
Cs-137
30.2
1.7
Am-241
433
8.0
Np-237
2 million
0.0
)
3.2 Barrier Failure Model
The failure of a logging source abandonment system means that all the unit components (barriers) have failed
and the radionuclides are released into the biosphere. Then the failure probability of the abandonment system can
be expressesed, according to Kim et al (1993), by the following integral.
( )=
( )
(
−
)
19
(
−
) ×
( −
)
2
5. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
= ∏
∑
+
www.iiste.org
" #($ %$& )'
+ ∏
()&( (#$ )
3
&
Where
= decay constant of the radionuclide
= failure rate of the barrier ,, , = A, B, C, and D
The survival probability density function of radionuclide is
the barrier B has failed at ≤ and barrier A has failed at
( ) at time when barrier C has failed at
≤ .
≤ ,
( ) are the survival probability density functions of the radionuclide , for the
Here ( ), ( ), ( ), and
single barriers A, B, C, and D, respectively.
The time dependent annual release rate, . ( ), of the radioactive nuclide to the environment is then obtained as:
.( )=
⋅
( )
4
The amount of radioactivity released to the geosphere is calculated on the basis of sequential failure of each
barrier due to corrosion (resulting from water infiltration) or human intrusion such as drilling operation. The
failure scenario for each barrier is summarized in Table 2 along with assumed Mean Time to Failure.
Table 2: Representation of Barrier Failure Scenarios
No Barrier
Failure Scenario
Range of Reference
MTTFa
Value
(year)
(year)
A
Cement Plug
Degradation of the cement plug due to water infiltration 300-4000
300
from rain fall or failure resulting from drilling activities.
B
Source
Corrosion of the carbon steel container due to water 750-1000
750
Container
infiltration or outright damage by drilling operations
C
Source Matrix Leaching or dispersion of source nuclide into water
5-900
6
D
Geological
Radioactivity release to environment by ground water. RdTw
RdTw
Structure
Mobility of radionuclide is based on retardation factor (Rd)
and water travel time (Tw)
a
These values are assigned on the basis of Kim et al (1993) and Cho et al (1992)
3.3 Geoshpere Model
The geosphere model is used to translate the radioactivity release rate into radionuclide concentration dispersion
across the geological structure by ground water.
The convection-diffusion equation (CDE) is a classic model for radionuclide dispersion in the soil profile. For
instance, 137Cs can be adsorbed onto soil particles and transported into the soil profile by infiltration and bulkmixing processes (i.e. wetting/drying and freeze/thaw cycles, and bioturbation). The CDE model does not
represent these processes explicitly, but instead treats soil-transport processes as analogous to the hydrodynamic
dispersion of a passive tracer, or to the Brownian motion of molecules in a liquid.
1
= ∇. (4∇ ) − ∇. (5 ) + .
1
5
C is the radionuclide concentration, v is the velocity and R is the sink.
Assumptions: It is assumed that the convective component of transport is negligible and that the diffusion
coefficient is constant and there are no sinks
The solution of equation (5) for a unit instantaneous release of radioactivity taking into account the infiltration
by groundwater is given by:
(8, ) =
1
√4;4
<=
>
6
The equation (6) which describes the evolution of radionuclide concentration C by diffusive processes is the
solution to the diffusion equation in a semi-infinite medium with no-flux boundary condition at the surface and a
unit instantaneous release at z = 0 and t=0, z is depth in the soil profile, D is the diffusivity or dispersion
20
6. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
coefficient, and t is time following abandonment.
3.4 Biosphere Model
The biosphere model is used to calculate the rate at which human ingests, through the biosphere pathways, the
radionuclides which emerge from the geosphere. There are many identified pathways of the radionuclide to man
such as drinking contaminated surface water, ingestion of milk, meat, fish, green and root vegetables, inhalation
of dust resuspended from a irrigated soil, and direct irradiation from the contaminated field. These pathways are
shown in Fig 6. However, owing to insufficiency of site-specific data, this study considered generic pathways of
drinking contaminated surface water. The surface water will be rivers, wells, lakes, reservoirs, and so on. In
order to obtain a more precise estimation of the amount of radionuclide which reaches man, the site-specific
biosphere model should be established. The annual ingestion rate to an individual through the drinking of
contaminated water pathway is given by:
@A ( ) =
.( )
@. ,C
B
7
Where
@A ( ) = Annual ingestion rate of an individual for radionuclide from the abandonment zone through the
pathway of drinking contaminated surface water (Ci/yr)
B = Volume flow rate (VOLFLOW) of the surface water (m3/yr)
@. ,C = Annual individual ingestion rate with the unit concentration (1 Ci/m3) of radionuclide in the surface
water through the pathway of drinking contaminated surface water (Ci/yr per Ci/m3)
Fig 6: Identified Pathways for Biosphere Model
3.5 Dose and Health Risk Model
This model evaluates doses to an exposed individual at any time after the abandonment and health effects due to
ingestion of radioactivities. The time dependent annual dose rate (Sv/yr) to an individual is obtained from
multiplying the annual ingestion rate, @A ( ), by a dose conversion factor for each nuclide :
4E ( ) = 3.7 × 10G ⋅ @A ( ) ⋅ 4 H IJ
8
Where
4E ( ) = annual dose rate to an individual for radionuclide from the source abandonment zone through the
pathway of drinking contaminated surface water.
3.7 × 10G = activity conversion factor (Bq/Ci)
4 H IJ = dose conversion factor for ingestion (Sv/Bq)
21
7. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
The dose conversion factors for each nuclide are listed in Table 3
Table 3: Dose Converstion Factor for Radionuclides
Nuclide
4 H IJ (Sv/Bq)
Cs-137
1.30 × 10 L
Am-241
1.10 × 10 M
Np-237
2.0 × 10 M
The total annual dose, 4EN ( ), from all the radionuclides considered is obtained by taking the sum of dose, 4E ( ),
for each radionuclide:
4EN ( ) = O 4E ( )
9
Radiological dose can be converted to carcinogenic risk using radionuclide-specific risk coefficients (also called
slope factor) developed by US EPA. Often the risk is calculated by applying a dose-to-risk (DTR) conversion
factor to the effective dose (the whole body dose). Radionuclide slope factors are age-averaged by calculating
doses to each target organ or tissue, apply age- and gender-specific risk factors, and integrate over a lifetime.
• External (uniform whole body) irradiation is 8 x 10-7 radiogenic cancers
(incidence)/millirem.
• For intakes, dose to risk conversion is radionuclide-dependent and varies between 1 x 10-7
and 3 x 10-6 per millirem
However BEIR – V estimated 5.0 × 10 Q (fatal cancer probability coefficient per unit Sv) for low-level doses as
a risk conversion factor, where only stochastic effects (fatal cancer) are considered.
. R, (S TUV W XSW TY Z)
= 4SR (A5/ZW) × 4. SU5 WR SU HTV SW (] W ] WRSU − A5)
10
4.0 Results and Discussions
The risks evaluation carried out for a Logging While Drilling (LWD) tool which contains 137Cs source and AmBe neutron source abandoned in oil well using the integrated model with the associated input parameters. With
the input parameters shown in Table 4, the integrated models developed were evaluated using MATLAB R2009a
codes developed and The calculated annual release rates, annual ingestion rates, annual individual dose rates and
annual risk rates of the two nuclides (Cs and Am) are shown in the Table 5 and Table 6
The data contained in Table 5 and Table 6 for Cs nuclides and Am nuclides respectively were used to make plots
of annual nuclide release rate, annual dose rate, and individual risk rate as shown in Fig 7, Fig 8 and Fig 9.
Table 4: Integrated Models Input Parameters
INPUT PARAMETERS
VALUES
Depth of Abandoned Source
15000ft
Initial Activity of Cs
2.0Ci
Initial Activity of Am
23Ci
Half-Life of Cs
30.2yrs
Half-Life of Am
433yrs
MTTF of Cement Plug
300yrs
MTTF of Source Container
750yrs
MTTF of Source Matrix
6yrs
MTTF of Geosphere
400yrs
Water consumption rate
Volume Flow rate of S/W
4L/day
1010 m3/yr
22
8. Journal of Environment and Earth Science
ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
www.iiste.org
Table 5: Risk Evaluation Parameters for Cs-137 Radionulide
Time (yr) Annual Release Rate (Ci/yr) Annual Dose Rate (Sv/yr)
10
2.675410E-09
7.039190E-09
50
9.665980E-10
2.543190E-09
100
2.707480E-10
7.123570E-10
200
2.124240E-11
5.589020E-11
400
1.307620E-13
3.440430E-13
500
1.025930E-14
2.699300E-14
800
4.954880E-18
1.303660E-17
900
3.887510E-19
1.022830E-18
1000
3.050070E-20
8.024950E-20
Annual Risk Rate (/yr)
3.519600E-10
1.271590E-10
3.561780E-11
2.794510E-12
1.720210E-14
1.349650E-15
6.518320E-19
5.114160E-20
4.012470E-21
Table 6: Risk Evaluation Parameters for Am-241 Radionuclides
Time (yr) Annual Release Rate (Ci/yr) Annual Dose Rate (Sv/yr) Annual Risk Rate (/yr)
10
1.430730E-08
3.186030E-07
1.593010E-08
50
1.212260E-08
2.704030E-07
1.352010E-08
100
9.854660E-09
2.202740E-07
1.101370E-08
200
6.512300E-09
1.461730E-07
7.308660E-09
400
2.843930E-09
6.436900E-08
3.218450E-09
500
1.879360E-09
4.271510E-08
2.135750E-09
800
5.423600E-10
1.248230E-08
6.241150E-10
900
3.584100E-10
8.283210E-09
4.141610E-10
1000
2.368490E-10
5.496720E-09
2.748360E-10
It could be observed that the annual dose rate from Am nuclides is relatively constant over a long period of time.
This is because of the high half-life time of the nuclide which is 433 years. This implies that it will take about
1000 years for the dose rate form Am nuclide to reduce by one-fourth.
However, the annual dose rate from Cs nuclides drops off drastically after like 120 years of abandonment in the
oil well. The reason for this is that the half-life of Cs nuclide is 30.2 years which is relatively low. Therefore,
after a period of about 500 years, the dose rate from Cs should have gone down to a safe level.
Plot of Annual Release Rate from Radionuclides
Radionuclide Release Rate (Ci/year)
1.00E-12
1.00E-14
1.00E-16
1.00E-18
Am
1.00E-20
Cs
1.00E-22
1.00E-24
1.00E-26
10
100
Time (year)
Fig 7: Annual Release Rate of Radionulides
23
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9. Journal of Environment and Earth Science
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Plot of Annual Dose Rate from Radionuclide
Annual Dose Rate (Sv/year)
1.00E-08
1.00E-12
Am
Cs
1.00E-16
1.00E-20
10
100
1000
Time (year)
Individual Annual Risk Rate (Cancer deaths/year)
Fig 8: Annual Dose Rate from Radionuclides
Plot of Annual Risk Rate from Radionuclides
1.00E-08
1.00E-12
Am
Cs
1.00E-16
1.00E-20
10
100
1000
Time (year)
Fig 9: Annual Individual Risk Rate from the Radionuclides
The average of the risk obtainable from the abandonment of radioactive logging sources in oil wells (due to Cs
and Am) was obtained from the Fig 5 to be 8.141 × 10 ^ cancer deaths/year and this can be compared to
normal annual risk of mortality from other sources of risk. This is clearly shown in Table 7.
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Table 7: Normal Annual Risk of Mortality*
Sources of Risk
Annual Risk Rate (Death Rate)
Smoking cigarettes
1.739 × 10 _
Natural Background Radiation
1.087 × 10 `
Drowning
2.696 × 10 `
Air Travel
6.522 × 10 a
Lightning
3.826 × 10 M
a
Nuclear Fuel Cycle
1.305 × 10 L
a
Low-Level Waste Repository
3.695 × 10 ^
b
Abandoned Logging Sources
8.141 × 10 ^
*
Estimated from E.L. Etnier and C.C. Travist, (1993)
a
Obtained from Kim et al (1993)
b
Obtained in this Study
The annual risk rate (8.141 × 10 ^ cancer deaths/year) from abandoned logging sources in oil wells is slightly
higher than the annual risk rate (3.695 × 10 ^ cancer deaths/year) from Low-Level Waste Repository. The
reason being that the site of low-level wastes repository is carefully selected and sufficient engineered barriers
are put in place to shield the biosphere from the effects of the wastes. Whereas logging sources are abandoned in
an unplanned site and efforts are just being made to contain the sources from contaminating the environment.
The implication of this is that 8 people out of 109 people that were exposed to these radionuclides would die of
radiation-induced cancer.
5.0 Management of Risk: Development of Logging Sources Abandonment Procedure
The template for radioactive logging sources plugging and abandonment procedures was developed using the
common requirements of Industry Standard, Regulatory Authority and Operator Best Practices as shown in Fig
10. The template has two sections which are Pre-abandonemt, and Abandonment sections.
Industry
Standard
Regulatory
Authority
Operator
Practices
Best
Figure 10: Common Requirement for Abandonment Template
5.1 Pre-Abandonment Phase
Whenever a sealed radioactive logging source gets lodged downhole, the licensee should be required by
regulation to do the following forthwith.
1. Notify the Regulatory Authority
2. Monitor the presence of radioactive contamination at the surface with survey meter and if there is a
detection of radioactive contamination, the Regulatory Authority should be notified immediately.
3. In a case where the lodged sealed source is still intact, then several attempts must be made to recover it
using different fishing methods. The recovery operation must be done in such a way that the sealed
source is not damaged in the process.
4. When it becomes apparent that efforts to recover the radioactive source will not be successful, then
abandonment procedure plan should be developed based on the following highlighted information about
the well: Date of occurrence, Type of sealed source (Cs or Am) and activity level, Depth of well, Depth
of lodged radioactive source, Surface location and identification of the well, Water Depth, Hole
conditions, Hole and Casing sizes
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5.2 Abandonment Phase
If, after making all reasonable attempts to recover a tool containing a radioactive source without a success, the
source shall be classified as irretrievable. Then, abandonment plans should be drawn up following guidelines
stated below but subject to the approval of appropriate regulatory agency before its implementation.
STEP 1: Leaving Minimum of 100ft drillpipe above the Source
In implementing the abandonment procedure, the standard practices with most operators is to leave about 100ft
to 200ft of drill pipe above the sources to act as a layer of defence against inadvertent intrusion or influx of
corrosive element into the sources. Afterwards, the radioactive source shall be immobilized and sealed in place
inside the drill pipe using cement slurries of specifications stated in STEP 2. The cement slurry should cover the
100-foot drillpipe which houses the radioactive source.
STEP 2: Immobilization and Sealing in Place of Radioactive Source with Cement Plug
In this study, the cement slurry design uses modified class G/H cement (based on API cement classification) for
the immobilization and sealing in place of the lodged sources. The modification done to the class G/H cement is
the addition of 1% nanosilica. The nanosilica is added to achieve the following advantages over ordinary class
G/H cement Ershadi et al (2011)
• It increases the Compressive Strength to 3023 psi at 1580F and P = 3000psi.
• It reduces the permeability by 99% and reduces the porosity by 33.3%
The other features of the cement slurry are given as shown in Table 8.
Table 8: Features of Cement Slurry
Cement Class
Water/Cement (W/C) ratio
Slurry Density
(gal/sk)
(lb/gal)
Class G + 1% nanosilica
5.0
15.8
Class H+1% nanosilica
4.3
16.4
STEP 3: Plugging of the Well
The common lodged sources scenarios and their plugging methods are enumerated in Table 9 for the vertical
wells.
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Table 9: Plugging of Wells Containing Radioactive Sources
Vertical Wells
1. Bottom Hole Abandonment:
Sources abandoned in the bottom of the hole shall
be covered with a (100-200)-foot standard colordye cement plug on top of which a mechanical stop
or deflector shall be set. The dye shall contrast with
the color of the formation to alert a re-entry
operator prior to encountering the source
2. Abandonment behind Casing String:
In a well where a logging source has been
cemented in place behind a casing string and above
total depth, upon plugging the well, a (100-200)foot color-dyed cement plug shall be placed
opposite the abandoned source inside the well bore
and a mechanical stop or deflector shall be placed
on top of the plug.
3. Producing Zone Abandonment:
If a well is to be deviated or sidetracked around a
lost radioactive source, then a (100-200)-foot
standard color-dyed cement plug (dyed with red
iron oxide) shall be placed above the abandoned
source, and an approved deflection device shall be
placed on top of the plug. The sidetrack
requirement shall be a horizontal distance of (1520)-foot from the lost radioactive source.
STEP 4: Mechanical Stop or Deflection Device
A well in which a radioactive source has been abandoned shall be mechanically equipped and plugged so as to
prevent either accidental or intentional mechanical disintegration of the radioactive source. An example of such
mechanical deflection device is whipstock.
STEP 5: Placement of Identification Plaque (if practical)
Upon plugging a well in which a radioactive source is left in the hole, the operator shall place a permanent
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plaque by welding or bolting or cementing it to the top of the well in a manner approved by the Regulatory
Authority such that re-entry cannot be accomplished without disturbing the plaque. The plaque shall serve as a
visual warning to a person re-entering the hole that a radioactive source has been abandoned in-place in the well.
The plaque shall depict the trefoil radiation symbol with the words ‘‘Caution, Radioactive Material’’ and shall be
constructed of a long-lasting material such as monel, stainless steel, bronze or brass. A typical plaque is shown in
Fig 11. The marker shall bear the following information:The words “CAUTION, RADIOACTIVE
MATERIALS”, Radiation symbol without the conventional color requirement, Date of abandonment, Name of
the Well Operator or Well Owner, Well name and well identification number, The sealed sources by
radionuclides and by activity level, The source depth and the depth to the top of the plug.
COMPANY NAME: W & T Offshore, Inc. Port Harcourt,
Nigeria
WELL:
OCS-G - 26168 A-6 STOO BP03 API 17-72440942-00
LOCATION: MAIN PASS BLOCK 279 OFFSHORE GOM
CAUTION
ONE 1.7 CU E CS-137 AND ONE 8.0 CURIE AM-24lBE
RADIOACTIVE SEALED SOURCES ABANDONED ON
6 December 2008 @ 5004 FT MD (4580 FT TVD)
PLUGBACK DEPT 4700 FT MD (4336 FT TVD)
DO NOT RE-ENTER THIS WELL
BEFORE CONTACTING
NIGERIA NUCLEAR REGULATORY
AUTHORITY
Fig 11: Typical Identification Plaque
6.0 Conclusions
The annual risk rate (8.141 × 10 ^ cancer deaths/yeeary) from abandoned logging sources in oil wells is slightly
higher than the annual risk rate (3.695 × 10 ^ cancer deaths/year) from Low-Level Waste Repository. The
reason being that the site of low-level wastes repository is carefully selected and sufficient engineered barriers
are put in place to shield the biosphere from the effects of the wastes. Whereas logging sources are abandoned in
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ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online)
Vol. 3, No.10, 2013
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an unplanned site and efforts are just being made to contain the sources from contaminating the environment.
The possibility of damaging the encapsulation of abandoned sealed source through human intrusion and natural
disruptive processes could be high. This could lead to the release of radionuclide into the environment.
However, the safety of the abandoned sources can be assured if dispersion of the radionuclide into the biosphere,
driven by natural processes, is retarded until they have decayed to a safe level and if human intrusion into the
source is unlikely. In order to achieve this, modified class G/H cement with the addition of 1% nanosilica has
been found to provide substantial standard cement slurry in terms of compressive strength, permeability and
porosity. This kind of cement slurry, when used for plugging and abandonment of radioactive sources, will
greatly retard the dispersion of radionuclide through the geopshere to the biosphere.
Subsequently, a template for abandonment procedure of radioactive logging source in oil well was developed
based on the requirements of Industry Standards, Regulatory Authority and Operator Best Practices. This
template should be adopted as a basis for development of abandonment plan, however, if hole conditions make it
impossible to abandon source as prescribed in the template, then alternate abandonment procedures should be
developed which should be subjected to the approval of the regulatory authority before implementation.
References
Bello, N.A (2007) “Regulatory Framework for Safety and Security of Radioactive Sources used in Nuclear Well
Logging”, presented at the 1-day Technical Meeting on the Abandonment of Radioactive Sources Stuck
in Oil Wells.
Kim, Y.N., Kim, J.K. and Kim, T.W. (1993):“Risk assessment for shallow land burial of low-level radioactive
waste” Waste Management 13 (8), 589–598.
Cho, W.J., Chang, S.H. and Park, H.H. (1992): “Uncertainty analysis of safety assessment for high-level
radioactive waste repository”, Waste Management 12 (1), 45–54.
Etnier, E.L. and Travist, C.C. (1993): “Risk of EnergyTechnologies”, Nuclear Safety, 24:671.
Ershadi, V., Ebadi, T., Rabani, A.R, Ershadi, L., Soltanian, H. (2011): “The Effect of Nanosilica on Cement
Matrix Permeability in Oil Well to Decrease the Pollution of Receptive Environment”, International
Journal of Environmental Science and Development, Vol 2., No. 2, April 2012
International Atomic Energy Agency (1991):”Inventory of Radioactive Material Entering the Marine
Environment: Sea Disposal of Radioactive Waste”, TECDOC 588, IAEA, Vienna.
International Atomic Energy Agency (1999):”Inventory of Radioactive Waste Disposal at Sea”, TECDOC 1105,
IAEA, Vienna.
International Atomic Energy Agency (2001):”Inventory of Accidents and Loses at Sea Involving Radioactive
Material”, TECDOC 1242, IAEA, Vienna.
29
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