AN ASSESSMENT OF BACKGROUND RADIATION LEVEL OF SOME SELECTED MINING PROCESSING IN NASARAWA
ABSTRACT
Human is exposed to background radiation in their environment with or without their consent; and the exposure to natural background radiation is an unpreventable event on earth. The assessment was conducted for the determination of the amount of background radiation revel of some selected mining processing in Nasarawa. This was carried out using RDS-200 universal survey meter. The assessment was done on the mining processing ranges from 0.501msv/yr to 0.758msv/yr. for the indoor reading and 0.139msv/yr to 0.267msv/yr for the outdoor reading. The radiation levels in these selected mining processing were found to be within the safe limit. These results would serve as a baseline upon which another exposures would be assessed and in the future serve as reference for dosimetry and decontamination in situation of radiation poisoning of these mining processing.
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Human exposure to background radiation is unavoidable. This is because we live in a “sea of radiation”. It is omnipresence nature in the atmosphere, terrestrial deposits and in our body makes it a unique area of assessing energy in our environment. Background Radiation is a long wavelength electromagnetic radiation that hits the earth uniformly from all direction. It represents energy left over from the “big bang” the explosion of the beginning of the universe. What makes it a background radiation is because of man’s environment most people often associate the word radiation with ionizing radiation (e.g as occurring in nuclear weapons, nuclear reaction) but it can also refer to electromagnetic radiation (i.e radio waves, infrared light, visible light and x-rays). This can also be ionizing radiation to acoustic radiation because energy radiate i.e. travels outwardly froth a source called an emitter in straight lines in all directions (Agba, 2016).
Natural Background radiation accounts for 80% of radiation source in our environment which includes cosmic radiation from the sun and outer space and consists of positives charged particles, form radioactive material found on earth surface as in rocks and soil as well as radiation in our bodies in form of element liker potassium 40. The first two sources mentioned as referred to as external sources of natural background radiation while the last is called the internal source of natural background radiation. The other 20% comes from the artificial background source like the nuclear power plants, nuclear weapon testing and medical procedures (x-rays and mammography) in medicine and dentistry (ICRP, 2020).
Radiation is classified in two forms based on energy level; the ionization form of radiation which is the high energy radiation capable of ionizing atoms. It includes Alpha Particles bête particles, gamma rays and neutrons. And the non-ionization form of radiation which is a low frequency and energy radiation. It includes ultraviolet rays, visible light microwaves, and radio waves.
Over the years the level of background radiation in our surrounding has grown significantly. A study conducted by Japan’s institute of radiological studies in 1977 shows that the increase in radiation level was due to nuclear power plant production. Other factors regarded as major contributors include nuclear reactor explosion mining activities, industrial waste and effluent from factories estimate of dose contribution in the environment shows that 85% of radiation dose received by man are derived from natural radionuclide while the remaining 15% comes from cosmic rays and nuclear process (IAEA, 2016).
In the year 2000, the average and the average background radiation for human being amounts to about 2.4 micro sievert per year (µSv/yr) and about 1µSv/yr comes from nuclear activities (UNCEAR, 2020). At sea level, the average cosmic radiation dose is about 26 mRem per year. At high elevation, the amount of atmosphere shielding cosmic rays decreases and thus the dose increases. Radioactive elements like uranium, thorium and atom which are the terrestrial emitting radio nuclides are also regarded as contributors to high level of background radiation (Ellwell, 2018). Radon for instance is a current health concern – radon gas formed from radioactive decay of natural uranium in the soil. It emits alpha radiation, raises from soil under houses and can build up in homes particularly well insulated homes (UNCEAR, 2020).
Exposure to radiation can cause severe damage to human biological system (Emeka, 2017). Although a dose of 25 Rems which is equivalent to 0.25mSv causes some detectable changes in blood, doses to near 100 Rems usually have no immediate effect. Dose above 100 Rems causes the first signs of nausea, vomiting, headache, some lost of white blood cells. Dose of 300 Rems on more cause temporary hair loss but also more significantly internal harm including damage to nerve cells and cells that line up the digestive tract (Agba, 2016). Severe loss of white blood cells which are the body defense system makes a radiation victim vulnerable to diseases. Radiation also reduces the blood platelets which aid blood clotting, so victims of radiation are vulnerable to hemorrhaging. Half of the people exposed to 450 Rems die and dose of 800 Rems are fatal. The main way of saving the cells of the body is to protect it from exposure to radiation. This is why radiation monitoring and measurement are quite essential in our society today (Hay, 2016).
1.2 Statement of the Problem
According to Agba et al., (2016), every person is exposed daily to variety of radiation whether he recognize it or not. This is due to the various activities in our immediate surroundings. In fact, the context of background radiation over the years has passed in silence especially in developing countries like ours Nigeria. If it is mentioned at all, it is mostly the theoretical possibilities that are highlighted and negligence in the study especially on it effect to man in his surrounding will continue to leave a threat to human existence. The study finds solution to question like; the various factors that lead to the variation in background radiation of different indoor surrounding of some selected mining processing in Nasarawa, the hazards of man’s continual exposure to radiation through different radiation emitting source and the possible protection and control measures to its exposure.
1.3 Aim and Objectives
1.3.1 Aim
The aim of this project is to measure the background radiation level of some selected mining processing in Nasarawa.
1.3.2 Objectives
In view of the aim of the study, the specific objective of the study will include:
- To evaluate the amount of radiation present in mining processing in Nasarawa
- To review the effects of long exposure to radiation
- To create awareness of the possible danger posed by long exposure to radiation sources.
1.4 Justification of the Study
The limit of radiation exposure for non radiation workers is 1millisievert/yr while that for radiation workers is 20 millisievert average 5yrs according to the International Commission on Radiological Protection (ICRP). As such there is a need to know the amount of background radiation exposure in the mining processing from which the annual exposure in the tin shade can be calculated and compared with international limit started by the ICRP. Hence, there is the need to frequently and increasingly notify the public about the threat posed by radiation to health in general – also information derived from the study will therefore.
- Provide database for information regarding management of background radiation level in mining processing.
- Create more awareness on the danger posed by background radiation.
- Serve as reference for further or subsequent research
1.5 Significance of the Study
The findings of this study will help in creating awareness of certain danger that comes with the background radiation to the workers in the selected mining processing in Nasarawa
1.6 Scope and Limitation of the Study
The study will focus on the assessment of the background radiation level of some selected mining processing in Nasarawa relative to the standard amount of absorbable radiation in order to determine the effect of background radiation to the general public. It is however limited due to the following challenges:
- Insufficient finance to carry out the research work
- Limited time
- Poor cooperation by tin shade owners