ABSTRACT
These findings documented the physical, chemical and heavy metal contents in leachate, borehole water, surface stream, treated water and soil samples around the municipal solid waste dumpsite at Uyo metropolis, Akwa-Ibom State, Nigeria. Samples were collected during the wet and dry seasons 2010/2011. The samples were analysed for the following parameters: heavy metals (Fe, Cu, Mn, Zn, Cr, Cd, Pb), anions (PO34,SO2-4,Cl–, NO–3, NH+4-N), essential metals (Na, K, Ca, Mg), total dissolved solids (TDS), dissolve oxygen (DO), Chemical oxygen demand (COD), pH, salinity, turbidity and conductivity. The results revealed that most of the parameters recorded for the leachate samples significantly exceeded the WHO international standards for drinking water in both seasons. Fe (47.33 and 113.13mg(L), Cd (2.29 and 14.47mg/l), Cu (5.78 and 35.87mg/l), Cr (1.63 and 7.63mg/l), Pb (12.33 and 31.13mg/l), Zn (17.33, and 34.5mg/l), BOD (52.2 and 159.6mg/l), Cl– (284.37 and 536mg/l), NO–3 (74.03 and 87.83mg/l), TDS (1709.5 and 2043mg/l) and DO (1.73 and 2.73mg/l). In leachate, all the heavy metals, Cl–, COD, salinity, and conductivity contents showed significant increase (P<0.05) while SO2-4 recorded significant decrease (P<0.05) during the dry season. The physico-chemical contents recorded for the borehole water and treated water samples in both seasons agree with the international standards for drinking water, except for high PO43- content (1.13 to 2.17mg/l) recorded for the borehole water samples in both seasons which exceeded the WHO permissible limit of 0.1mg/l for drinking water. The borehole water sample recorded significant increase (P<0.05) in Fe, Mn, Na, K. and a significant decrease in SO2-4 contents during the dry season. The stream water sample recorded high Fe (0.61 and 2.5mg/l) content in both seasons and high Mn (2.37 mg/l), Cr (0.42mg/l), Cd (0.46mg/l) and Cu (3.95mg/l) contents during the dry season which exceeded the WHO international standard for drinking water. The stream water samples recorded significant increase in BOD5, Cu, Mn, Cd and Cr contents during the dry season (P<0.05). The heavy metal contents recorded for soil samples from the dumpsite, from 10 and 20m east, west, south and north of the dumpsite and from the control site were all within the WHO international standards in both seasons. The heavy metal contents in the dumpsite soil sample in both seasons were significantly higher; pb (9.90 and 11.82mg/kg), Zn (1370 and 146mg/kg), Ni (12.56 and 11.82mg/kg), Cr (3.60 and 4.05mg/kg) Cd (9.05 and 12.2mg/kg) and Mn (94.0 and 91.2mg/kg) In both seasons than the control; Pb (3.78mg/kg) Zn (50.90mg/kg), Ni (2.19mg/kg), Cr (1.06mg/kg), Mn (44.27mg/kg), and Cd (1.09mg/kg). Heavy metal contents for soil samples 10 and 20m east of the dumpsite were also significantly higher (P<0.05) than that of the control. This study infer that the solid waste dumpsite is affecting the natural quality of the ambient environment. Therefore indiscriminate dumping of solid waste at the dumpsite should be prohibited.
TABLE OF CONTENTS
Title Page – – – – – – – – i
Declaration – – – – – – – – ii
Certification – – – – – – – – iii
Dedication – – – – – – – – iv
Acknowledgements – – – – – – – v
Abstract – – – – – – – – vii
Table of contents – – – – – – – viii
List of Tables – – – – – – – – xiii
List of Figures – – – – – – – – xv
List of plates – – – – – – – – xvii
CHAPTER ONE
1.1 Background of the study – – – – 1
1.2 Statement of the problem – – – – 7
1.3 Objectives of study – – – – 8
1.3.1 General objectives – – – – 8
1.3.2 Specific objectives – – – – 8
1.4 Expected benefits of the study – – – – 9
1.5 Research questions – – – – 9
1.6 Scope of the study – – – – 10
CHAPTER TWO
2.1 Meaning of waste – – – – 11
2.1.1 Solid waste – – – – 11
2.2 Solid waste dumpsite – – – – – 14
2.2.1 Open dumps system – – – – – 14
2.2.2 Sanitary landfill system – – – – – 15
2.3 Waste management – – – – – 15
2.3.1 Landfills – – – – – 16
2.3.2 Incineration – – – – – 16
2.3.3 Recycling – – – – – 17
2.4 Leachate – – – – – 17
2.4.1 Leachate production – – – – – 20
2.4.1.1 Influence of Source – – – – – – 20
2.4.1.2 Processes – – – – – – 20
2.4.1.3 Timing of landfill stabilization – – – – 22
2.5 Pollution – – – – – – – – 23
2.5.1 Ancient culture – – – – – 23
2.5.2 Official acknowledgement – – – – 23
2.5.3 Modern awareness — – – – – 25
2.5.4 Forms of Pollution – – – – – 27
2.6 Water Pollution – – – – – 28
2.6.1 Water pollution Categories – – – – 29
2.6.1.1. Surface Water pollution – – – – – 29
2.6.1.2 Groundwater pollution – – – – – 31
2.6.2 Causes of water pollution – – – – – 31
2.6.2.1 Pathogens – – – – – – 32
2.6.2.2 Chemical and other contaminants – – 33
2.6.3 Measurement of water pollution – – 34
2.7 Water quality – – – – – – – 34
2.8 Soil/land pollution – – – – – 33
2.8.1 Causes of soil pollution – – – – 36
2.8.2 Effects – – – – – – – 36
2.8.2.1 Health effects – – – – – – 36
2.8.2.2. Ecosystem effects – – – – – 37
2.8.2.3 Clean up options – – – – – 38
2.9 Review of related studies – – – 39
CHAPTER THREE
3.1 The study area – – – – – 45
3.2 Material and methods – – – – – 47
3.2.1 Sampling – – – – – – – 47
3.2.2 Samples treatment – – – – – – 51
3.2.2.1 Treatment of water samples – – – – 51
3.2.3 Treatment of leachate sample – – – – 51
3.2.4 Treatment of soil sample – – – – – 52
3.2.5 Preparation of stock solutions – – – 52
3.2.6 Chemical analysis – – – – – 52
3.2.6.1 Determination of pH and temperature – 53
3.2.6.2 Determination of chemical oxygen demand (COD) 53
3.2.6.3 Determination of Dissolved oxygen (DO) – – 53
3.2.6.4 Determination Biochemical Oxygen demand (BOD) 54
3.2.6.5 Determination of total dissolved solids (TDS) – 54
3.2.6.6 Determination of Major Anions – – – 55
3.2.6.6.1 Determination of Phosphate (PO43-) – – 55
3.2.6.6.2 Determination of Nitrate (NO3–) – – – 55
3.2.6.6.3 Determination of Sulphate (SO42-) – – 55
3.2.6.6.4 Determination of Chloride (Cl–) – – – 56
3.2.6.6.5 Determination of nitrite (NO2) – – – 56
3.2.6.6.6 Determination of Ammonium Nitrogen – – 57
3.2.7 Determination of Sodium (Na) and Potassium (K) 57
3.2.8 Determination of heavy metals – – – 57
3.3 Data Analysis Technique – – 57
CHAPTER FOUR: RESULTS AND DISCUSSION
- Means and standard deviations of some physic-
chemical contents in leachate ground
water, stream water and treated water samples – 58
- Mean concentrations of pH temperature turbidity
salinity and conductivity in leachate, groundwater,
stream water and treated water samples – – 58
- Mean concentrations of DO, BOD, COD,
Total suspended solids (TSS) and Total
dissolved solids (TDS) in leachate groundwater,
stream water and treated water samples – 69
- Mean concentrations of some major anions
In leachate, groundwater, stream water and treated
Water samples – – – – – – – 79
- Mean concentrations of essential cations in leachates,
Ground water, treated water and stream water samples 87
- Mean concentrations of heavy metals in leachate
Groundwater stream water and treated water
Samples – – – – – – – – 93
- Mean concentrations of heavy metals in soil along
Wastes and non wastes disposal sites – – – 100
4.3 Discussion – – – – – – – 115
4.3.1 Physico-chemical characteristics of leachate,
groundwater, stream water and treated water samples 115
- Heavy metal characteristics of soil samples
along wastes and non-wastes disposal sites – – 137
- Spiked samples – – – – – – – 144
CHAPTER FIVE: SUMMARY AND CONCLUSION
- Summary and conclusions – – – – – 150
- Recommendations – – – – – 152
5.3 Contribution to knowledge – – – – – 153
5.4 Suggestion for further works – – – – 153
References
CHAPTER ONE
INTRODUCTION
- Background of the study
The municipal solid waste dumpsite (MSWD) examined is located within the barrack’s road street at Uyo Metropolis; Akwa – Ibom State. The dumpsite examined contains both biodegradable and non biodegradable materials of all sorts. The different waste materials may contain different physical, chemical and biochemical properties. In the presence of atmospheric water, high temperature and high microbial populations, these waste materials may decompose and get dissolved in the presence of water to generate a waste liquid substance called leachate. This waste water produced may infiltrate into the ground water aquifer, it may be washed into a near by surface stream and it may affect the soil properties. When humans come into direct contact with such contaminated samples, it may lead to many health problems.
Pollution occurs when a product added to our natural environment adversely affects nature’s ability to dispose it off. A pollutant is something which adversely interferes with health, comfort, property or environment of the people. Generally, most pollutants are introduced in the environment as seawage, waste, accidental discharge and as compounds used to protect plants and animals. There are many types of pollution such as air pollution, water pollution, soil pollution, nuclear pollution and oil pollution (Misra and Mani, 1991).
Solid wastes other than hazardous and radioactive materials are often referred to as Municipal Solid Waste (MSW). Municipal solid waste is useless unwanted material discharged as a result of human activity. Most commonly, they are solids, semi-solids or liquids in containers thrown out of houses, commercial or industrial premises (Nyangababo and Hamya, 1980). Municipal solid waste varies in composition, which may be influenced by many factors, such as culture affluence, location etc. Municipal solid waste management depends on the characteristics of the solid wastes including the gross composition, moisture contents, average particle size, chemical composition and density, in which knowledge of these usually helps in disposal plans (Sally, 2000).
In Nigeria, agencies like the Federal Environmental Protection Agencies (FEPA), Ministry of environment, Environmental Sanitation Authorities, for example Akwa Ibom State Environmental Protection Agency (AKSEPA) and even local authorities are responsible for planning a defined line of action for the disposal of waste generated on daily basis in our society.
The report that refuse dumps have caused traffic delays in some strategic parts of our urban centers and cities is an example of poor management of refuse dumps in Nigerian towns and cities (Umaakuta and Mba, 1999). According to Eddy, Odoemelem and Mbaba (2006), the series of problems are as a result of lack of designed strategies that can be based on scientific principles and approach.
However, human endeavours, such as technology, industrialization, construction, trade, commerce, as well as nutrition have rendered the whole environment system a “throw away society”. This is true because indiscriminate disposal of waste coupled with increasing world population and urbanization have combined to worsen the situation day in, day out (Eddy et al., 2006).
According to Holmes (1992), site selection for waste disposal is generally based on geographic rather than geological and hydro geological considerations, that is the closer the site to the source of the waste the better in terms of transport cost reduction. It is not uncommon therefore to find waste disposal sites within municipal boundaries and surrounded by residential areas. Clearly such sites pose-serious health risk just in terms of problems associated with litter, stray dogs, scavenging birds, rats and air borne contaminants from mobilization of fine particulate matter.
Despite the best attempts at waste avoidance reduction, reuse and recovery (recycling, compositing and energy recovery), landfills and waste disposal sites are still the principal focus for ultimate disposal of residual wastes and incineration residues world-wide (Waite, 1995). The placement and compaction of municipal wastes in land fills facilitates the development of facultative and an aerobic conditions that promotes biological decomposition of land filled wastes. Hence, leachates of diverse composition are produced, depending on site construction and operational practices, age of the landfill, landfill method, climatic and hydro geological conditions and surface water ingress in to the landfill (Campbell, 1993).
A landfill is an engineered waste disposal site facility with specific pollution control technology designed to minimize potential impacts. Landfills are usually either placed above ground or contained within quarries pits. Landfills are sources of groundwater and soil pollution due to the production of leachates and its migration through refuse (Christensen and Stengmann, 1992).
According to Amina, et al., (2004), leachate corresponds to atmospheric water that has percolated through waste, interacting with bacteriological activity and especially organic substances. Its composition is a function of the nature and age of the land fill, type of waste, the method of burying, the geological nature of the site and climate.
Leachate pollution is a result of mass transfer process. Waste entering the landfill reactor undergoes biological, chemical and physical transformations, which are controlled among other influencing factors, by water input fluxes. In the reactor, three physical phases are present; the solid phase (waste), the liquid phase (leachate) and the gaseous phase. In the gaseous phase, mainly carbon (prevalently in the form of CO2 and CH4) is present. The main environmental aspects of landfills leachate are the impacts on surface water quality, ground water quality as well as soil quality, if leachate is discharging into these bodies (Christensen et al., 1992).
According to Paster, et al., (1993); De-vare and Bahadir, (1994), uncontrolled leachates may exert deleterious effects on the environment, especially the input of high concentrations of organic leachate and inorganic solutions of metals at low oxidation states into water course which apparently depletes the dissolved oxygen content of the water and ultimately lead to extinction of all oxygen depending life. Also the non- biodegradable organic compounds in the leachate will persist for a long time. These compounds may adversely affect aquatic species when they are assimilated into food chains.
Ground water is that portion of subsurface water which occupies that part of the ground that is fully saturated and flows into a hole under pressure greater than atmospheric pressure. Groundwater occurs in geological formations called aquifer. An aquifer (gravel/sand) may be defined as a geological formation that contains sufficient permeable materials that yield significant quantities of water to wells and springs; this implies an ability to store and transmit water (Chae, 2000).
Groundwater is an important source of drinking water for human kind. It contains over 90% of the fresh water resources and is an important reserve of good quality water. Groundwater, like any other water resource, is not just of public health and economic value it also has an important ecological function (Armon and Kitty, 1994). Groundwater contamination by landfill leachate is increasingly recognized as a serious problem (Hussan, et al., 1989; Loizidous and kapetanois, 1993; kwanchanawong and Kootlakers, 1993; Al-Muzains and Muslamani, 1994).
Soil is the collection of natural materials occupying part of the earth surface that may support plant growth, and which reflects the pedogenetic processes acting over time under the associated influences of climate, relief, living organisms, and parent materials. Soil pollution is caused by the removal or addition of substances and factors that decreases its productivity, quality of plants and ground water. Landscape pollution is simply the conversion of fertile land to barren one by dumping wastes over it.
Indiscriminate dumping of refuse can influence soil physico-chemical properties, but can still be used for farming provided the risks associated with its usage are continuously assessed and controlled. The introduction of metal contaminants into the environment could result from various sources; a few of which are application of sea wage materials, and leaching of garbage. The impact on man would be felt if the metals enter into the food chain and accumulate in living organisms (Moore and Ramamoorthy, 1984; Altundogan, et al., 1998).
Continuous disposal of municipal wastes in soil may increased heavy metal concentrations. Heavy metals may have harmful effects on soils, crops, and human health. However, there is generally not strong relationship between the concentration of heavy metals in soils and plants because it depends on many factors such as soil metal bioavailability, plant growth, and metal distribution to plants parts.
Apart from the contamination of soil, water and agricultural land by other elements, lead alone has a poisoning effect. According to Akaeze (2001), the toxicity of lead could lead to encephalopathy, renal effect, and hematological effect. The WHO, had confirmed the effects of lead intake to include, abortion, infant mortality, malformation of foetus, genetic mutation, retarded growth, intoxication, depression of respiration and chromosomal aberrations. Smith, (1976), stated that heavy metals can be introduced into the environment through high tension electricity supply lines, municipal solid wastes and building materials. Sommers, et al., (1976), explains that copper is an essential constituent of all organisms, but if the copper concentration is increased above normal level, it becomes highly toxic. An increase in concentration of copper in the ocean by one part per billion has resulted in the death of several species of phytoplankton and the eggs of some fishes of open oceans. Based on these, researchers have opted to suggest ways of controlling the generation of wastes and effects on the environment.
Akpan (2001) observed that the major cause of land degradation in Uyo is solid waste, and on the characteristics of wastes, papers, food remains, metal scraps, tins, cans, rubber containers, plastics, cellophane bags, worn-out tyres, and tubes were identified as the major components of solid waste. Apart from the fact that solid waste degrade the environment, and pose problems to the aesthetic value of the environment, Etekpo (1999) has confirmed that health hazards associated with improper disposal of solid waste include;
- harbouring and favouring rodents breeding and other harmful reptiles
- empty can which favour mosquito breeding
- putrescible wastes emit offensive odour thus polluting the air.
- Statement of the problem
Humans and other living organisms depend on a healthy environment for good health. The Barrack’s road dumpsite examined is situated very close to residential areas. These areas use borehole water, and a nearby stream located closed to the dumpsite for drinking and for other domestic activities. Soil around the dumpsite is used for farming activities. Rapid population growth and industrialization, coupled with indiscriminate dumping of solid wastes at the site, with little or no sound solid waste management plants at the study area have contributed to increase the volume of solid wastes at the dumpsite in an alarming rate. The different wastes types at the dumpsite, possess different physical, chemical and biochemical properties. The waste water produced from the decomposed wastes materials each times it rains, may drain into the nearby surface stream, may leach into the sub-surface soil and then into the groundwater aquifers. During this process, the boreholes, stream water and soil samples around the dumpsite may become contaminated. This may be very possible in the study area because the soil texture show that soil around the dumpsite and even outside the dumpsite show very high percentage coarse sand which is highly conducive to leachate transport. When humans and other animals come into direct contact with the contaminated samples they may face serious health challenges. With the desire to know the present quality of the borehole water, surface stream and soil around the dumpsite, the researcher deemed it necessary to determine the physio-chemical characteristics of leachate from the dumpsite, the borehole water, surface stream and soil sample around the solid wastes dumpsite which are known to impact on human health. The results of this findings may reveal the present qualities of the boreholes, surface stream and soil around the dumpsite.
- Objective of study
- General objective
To characterize leachate, groundwater, stream water and soil in the vicinity of a municipal dumpsite at Uyo metropolis to determined the level of impact of the dumpsite on the ambient environment.
- Specific objective
1) To assess and compare the physic-chemical properties of leachate, borehole, surface stream and treated water samples around the barrack’s road dumpsite with the international standard for drinking water.
2) To assess and compare the heavy metal contents of soil samples from the dumpsite, samples from the control site (800m) and samples from 10 and 20m outside the dumpsite in the north, south, west and east transects with the internal standards.
3) To compare the physic-chemical contents and heavy metals recorded for leachate, borehole water, surface stream treated water and soil samples during the wet and dry seasons.
- Expected benefits of the study
This study is necessary because it is hoped that through its outcome, the magnitude of the environmental contamination in the study area will be highlighted.
To the author, this work is so important since it serves as a medium through which he can address the numerous problems associated with the waste dump site.
The outcome of this study may ginger the government to adopt appropriate waste management strategies and control measures over indiscriminate dumping of waste.
Further more, it is hoped that the findings of this study will motivate other interested researchers in and outside the study area; thus helping to broaden our knowledge which is a prerequisite to formulation of effective control strategies in the future.
Finally, the result of this findings will be included into the limited literature of pollution studies in the study area, and to the numerous existing literatures on studies around waste dumpsites.
- Research questions
- Why did you embark on pollution studies in the vicinity of the chosen dumpsite?
- Was the levels of physico-chemical parameters and heavy metal in all the samples analysed within the permissible limits?
- Was there any variation in physico-chemical parameters in all the samples analysed during the wet and dry seasons?
- Was there any significant difference in heavy metal concentrations in soil at dumpsite compared with soil outside the dumpsite?
- Scope of the study
These findings, examined the physico-chemical and heavy metal characteristics of leachate, borehole water, treated water, stream water and soils at the vicinity of a municipal solid wastes dumpsite at Uyo metropolis, Akwa-Ibom State, SE Nigeria, during the wet and dry seasons.
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