The study assessed the impact of dumpsites on their immediate environments. The particulate dust, hand-dug waters, dumpsite–leachates and refuse waste soils were collected in both the dry and wet seasons while gaseous pollutants and other field data were determined in situ using gas mobile gas sensors. Also, young chickens were fed with the solid wastes and leachates for a period of three months in each site across the seasons and then sacrificed. Blood, hair, urine and nail samples were also collected from people residing close to the dumpsites in both the dry and wet seasons. The percentage recoveries of metals were determined on the samples by spiking experiment in order to validate the analytical method and technique used for the analysis. The characterization of the refuse wastes across the sites revealed the ranges of 4.24 to 44.23, 0.85 to 26.74, 13.10 (SH) to 42.11(JK), 16.33(SH) to 58.83(DA) and 3.79 (NTC) to 30.34% (PR) for plastic, papers, textiles, polythene bags and wood, respectively across the sites. The concentration ranges of CO, H2S, FL, SO2, NO2, NH3 across the seasons were 1.50 (CTR) to 11.40(SA), 0.001(CTR) to 0.0039(RA), 0.001(CTR) to 0.0085(SA), 0.001(CTR) to 0.039(SH), BDL(CTR) to 0.0039(JK) and 0.001(CTR) to 8.65(SH)ppm, respectively. The concentrations ranges of these gases were higher than the standard limits of 9(CO), 0.03(H2S, SO2), 0.08(FL) and 0.05ppm (NO2, NH3) with few exceptions. Also the ranges of particulates, relative humidity and temperature of the air at vicinity of the dumpsites across the seasons were 0.105 (KU) to 19.305 (RA)ppm, 6.35(AJ) to 77.35(CTR)% and 27.25(CTR) to 38.1000C(RA), respectively. These levels across the sites and seasons were generally above the standard limits of 0.03ppm and 250C for particulate gases and temperature. The concentration ranges of Zn, Cd, Cu, Pb and Hg in the particulate dust across the seasons were 1.40(JK) to 210.60(SA), BDL (CTR) to 3.74 (RA), 0.241 (KU) to 390.0 (JK), 2.26 (CTR) to 78.260(SH) and BDL (CTR) to 25.69(AJ),
respectively. The ranges of the bioavailable fractions of Zn, Pb, Cu, Cd and Hg in the soils across the seasons were 4.00 (NTC) to 79.08 (BG), 5.37 (SA) to 39.65 (CTR), 0.35 (RA) to 68.57(NTC), 28.14 (SH) to 65.74(DD) and 24.068 (SH) to 80.52% (BG). Also the ranges of the bioavailable fractions of Zn, Pb, Cd, Cu and Hg in leachates samples across the sites were 53.387(NTC) to 95.625(AJ), BDL(CTR) to 97.584(BG), 96.452(BG) to 1100(KU, CTR, AJ, SA, SH, RA, PR, NTC), BDL(CTR) to 100(RA, JK, DD) and 53.848(KU) to 100%(SH, SA, DD). Also the ranges of 31.499(NTC) to 99.513(AJ), BDL(CTR) to 100(BG, DD, SA), BDL(CTR) to 100(RA, DD, JK), 67.884(PR) to 100(NTC, RA, SA, KU, JK, DD & BG) AND 85.729(NTC) to 100%(BG, CTR, DD, JK, KU, SA and PR) for Zn, Pb, Cd, Cu and Hg. Also, the water quality indices (WQI) of 123799.1 and 110501.6 were recorded in wet and dry seasons and were >300, indicating that they were unfit for drinking. Also, the concentration ranges of BDL (CTR) to 8.844(JK), BDL(CTR) to 2.850(BG), BDL(CTR) to 0.099(BG), BDL(CTR) to 128.017(NTC) and BDL(CTR) to 83.122mg/kg(DD) were recorded for Zn, Pb, Cd, Cu and Hg in the chicken samples across the sites and seasons. Similarly, the concentration ranges of Zn: 0.414 to 1.102mg/L(RA), 0.738(RA) to 4.047mg/L(DD), 0.485(JK) to 8.568mg/kg(DD) and 0.719(BG) to 13.641mg/kg(NTC); Pb: 0.060(RA) 0.180mg/L(JK), 0.011(CTR) to 0.244mg/L(JK), 0.090(PR) to 0.900mg/kg(DD), BDL(CTR) to 0.413mg/kg(AJ); Cu: BDL(AJ) to 0.088mg/L(PR), BDL(CTR) to 0.171mg/L(PR), BDL(CTR) to 0.905mg/kg(DD), BDL(CTR) to 0.312mg/kg(AJ); Cd: BDL(DD) to 0.029mg/L(KU), BDL(DD) to 1.648mg/L(RA), BDL(DD) to 1.144mg/kg(KU), BDL(DD) to 1.119mg/kg(NTC) and Hg: BDL(CTR) to 3.187mg/L(NTC), BDL(CTR) to 3.460mg/L(SA), BDL(CTR) to 3.871mg/kg(RA), BDL(BG, CTR) to 2.935mg/kg((DD) were recorded in the urine, blood nail and hair samples of human residents of the dumpsites. The results indicate that the levels of Pb, Cd and Hg were generally above the
toxic limits of 0.001, 0.05 and 0.30mg/kg in the human residents. The non-toxic bismuth electrode was designed and tested which shows the detection limits of 0.005, 0.029, 0.033, 0.027 and 0.570μM for Cu, Pb, Zn, Cd and Hg, respectively. High levels of these gases and toxic metals reduce the oxygen carrying capacity of the blood, block oxygen transfer, poison cell enzymes, etc. The concentrations of the metals in chicken samples were generally below the tolerable limits with few exceptions which clearly show that the residents at the vicinity of these dumpsites are directly affected. Further work on bismuth working electrode should be carried out to improve the detection limits of these metals for environmental studies.
1.0 INTRODUCTION 1.1 Background to the Study The term ―solid waste‖ means garbage, refuse, or sludge from a waste treatment plant, water supply treatment plant, or air pollution control facility and other discarded material including solid, liquid, semisolid, or contained gaseous material resulting from industrial, commercial, mining and agricultural operations (US Law –Solid Waste Act 2, 1999). The term disposal means the discharge, deposit, injection, dumping, spilling, leaking, or placing of any solid waste, hazardous waste on any land or water so that such solid wastes, hazardous wastes, or any constituent thereof may enter the environment or be emitted into the air or discharged into waters including ground water from community activities (US Law-Solid Waste Act 2, 1999, Salam, 2010). The disposal of waste in the world is a problem that continues to grow with the development of industrialized nations and the growth of population. All over the world the talk is about various ways of handling garbage. It was estimated that 1.375billion tons of solid waste are generated annually and this number is expected to increase by 20 % (WHO, 1999). Solid wastes were classified into three different categorie: non-hazardous, hazardous and special wastes. Non-hazardous wastes are those that pose no immediate threat to human health and the environment while hazardous wastes have common hazardous properties such as ignitibility, reactivity etc. The last type, special waste, is very specific in nature, some are radioactive and they are regulated with specific guidelines (Luke, 2008).
Currently, world cities generate about 1.3 billion tonnes of solid waste per year (What a waste, 2013). This volume is expected to increase to 2.2 billion tonnes by 2025
(What a Waste, 2013). Waste generation rates will more than double over the next twenty years in lower income countries. Globally, solid waste management cost will increase from today‘s annual $205.4billion to about $375.5billion by 2025. Cost increases will be most severe in low – income countries (more than five – fold increases) and lower – middle income countries (more than five – fold increases) (What a Waste, 2013). Poorly managed waste has an enormous impact on health, local and global environments, and economy. Improperly managed waste generally results in down-stream costs higher than what it would have costed to manage the waste properly (What a waste, 2013). In 1999, the World Bank published What a Waste: Solid Waste Management in Asia (Hoornweg and Thomas, 1999) with an estimate of waste quantities and composition for Asia (What a Waste, 2013). In the intervening decade more accurate and comprehensive data became available for most regions of the world (What a Waste, 2013). OECD estimates are typically reliable and consistent added to these were comprehensive studies for China, and India and the Pan American Health Organisation‘s study for Latin America. Therefore, a global update of 1999 report is possible and timely (What a Waste, 2013). Solid waste collection and disposal have become a global business, the European school is rather dominated by policies initially espoused in Germany and later modified by the 15 – member European Union (EU). The underlying principle is ―polluter pays‖. The companies that manufacture and sell products are the ―polluters‖ not the consumers who purchase the products. Therefore, the EU has decreed that polluters should pay to collect and recycle all the packaging materials (Vasuki, 2001).
Most of the countries within the West African sub-region are emergent nations which, for along time, have been grouped among the less developed countries of the world.
Due to the low level of development, these countries have generally considered economic growth, social and educational development and industrialization as key development priorities, while protection of the environment has not been given the same importance. The cities of the third world countries are growing at very rapid rates compared to those in the developed nations. For instance, a United Nations Habitat report observed that Africa is the fastest urbanizing continent having cities like Nairobi, Cairo, Lagos and Kinshasa, among others, growing at fast rates that would make them triple their current sizes by the year 2050 (UN-habitat, 2009). The increasing growth of cities therefore has implication for municipal waste management among other social services required in the urban communities. Data from many of the cities show inadequacy in the social services like shelter, provision of safe drinking water and efficient management of solid waste. The cities are, therefore, littered with mountains of rubbish in the landfills and open waste dumps which are covered with flies and thus serve as breeding grounds for rodents and mosquitoes which are carriers of diseases (UN-habitat, 2009). Industrialization and population increment result in changes in the composition and quantity of waste generated. This is one of the main causes of environmental pollution and degradation in many cities of the developing world (UNIDO, 2003). Poor waste management poses several challenges for the well-being of the city residents, particularly those living adjascent to the dumpsites due to the potential of the waste to pollute the water, food sources, land, air and vegetation (Njoroge et al., 2007). Dumping of solid wastes without proper separation increases the concentration of heavy metals such as arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg) and zinc (Zn). These heavy metals when present in solid wastes have been known to produce major environmental impacts (Suman et al., 2011; Ebong et al., 2007).
Studies have shown that soil and groundwater system can be polluted due to poorly designed waste disposal facilities, leakage from underground storage tanks and agricultural wastes. Soil and groundwater acidification and nitrification have been linked to waste dumps (Bacud et al., 1994) as well as microbial contamination of soil and groundwater system (Awomeso et al., 2010; Amadi et al., 2011). The contamination of soil, water and air with heavy metals even at low concentrations are known to have potential impact on the environmental quality and human health. These metals also pose a long term risk to ground water and ecosystem (Ebong et al., 2007). Reports further indicate that these metals are toxic or poisonous even at low concentrations and create definite health hazards when they enter the ecosystem (Lenntech et al., 2004; Duruibe et al., 2007; Okoronkwo et al., 2006). Cancer, heart diseases and teratogenic abnormalities are attributed to groundwater pollution via leachate from the waste dumps. Increase in population and rapid expansion of cities have resulted to generation of huge amount of waste (Sia Su et al., 2008).
Pollution of soil by leachate from surrounding municipal waste dumps has been recognized for a long time (Alloway et al., 1990; Amadi et al., 2010). In Nigeria, like in other developing countries, open dump is the only available option for solid waste disposal in its cities. The depressions into which solid wastes are often dumped include valleys and excavations (Amadi et al., 2011). Solid waste management has remained an intractable environmental sanitation problem in Nigeria. This problem has manifested in the form of piles of indiscriminately disposed heaps of uncovered waste and illegal dumpsites along major roads and at street corners in cities and urban areas. This problem is compounded by rapid urbanization and population growth which have led to generation of enormous quantities of solid waste which are often
discarded by open dumping (Uwakwe, 2012). Open dumping of municipal solid waste disposal practiced by three fourth of countries and territories around the world. It is the major cause of environmental degradation and public health concerns in many developing countries including Nigeria. These waste dumps may contain a mixture of generated waste and toxic infectious or radioactive wastes and are susceptible to burning and exposure to scavengers (Uwakwe, 2012). There are a number of major risks and impacts of the dumpsites on the environment. Air pollution from open burning due to emission of greenhouse gases, rats and fly infestation and nuisance effects are among the health and environmental impacts of poor solid waste management. In addition, scattering of wastes by wind and scavenging by birds, animals and waste pickers create aesthetic nuisance. Malodour emanating due to degradation of the waste in the dumpsite has nuisance effect and decreases the economic and social values in the locality (Uwakwe, 2012). In many dumpsites, the waste is directly increasing global concern over the public health impact attributed to environmental pollution particularly the environmental quality and human health risks associated with the waste dumps. The World Health Organization estimated that about a quarter of diseases facing mankind today occur due to prolongeg exposure to environmental pollution and it seems to be the highest (Uwakwe, 2012). To determine whether to rehabilitate and close or remediate, upgrade and operate a dumpsite may require an environmental impact assessment studies. In countries like Nigeria where the number of existing dumpsites (both legal and illegal) are many, economic considerations of evaluation process must be taken into consideration in recommending a suitable approach or methodology. Assessing the relative health and environmental hazards posed by the dumpsites existing throughout the
developing countries help prioritize, plan and initiate dumpsite rehabilitation (Uwakwe, 2012). Solid waste handling and disposal is a major environmental problem in many urban centers of Nigeria (Amusan et al., 2005). City dwellers have long contended that any form of waste with proper composting and processing can be made into fertilizer. Municipal refuse may contain paper, food wastes, metals, glass, ceramics and hairs (Carlson, 1976). Dumpsite soils are known to contain different kinds and levels of heavy metals depending on the peculiarities of the neigbourhood (Harrison and Chirgawi, 1989; Udosen et al., 1990; Odukoya et al., 2000). According to Carlson (1976) and Alloway (1996), heavy metals in dumpsites soils can be accumulated to environmentally hazardous levels. Heavy metals are environmental pollutants (Onyeri et al., 1991; and Gratani et al., 1992) and could be increasingly introduced anthoropogenically as co-products and finished products into dumpsite soils (Shuaibu and Ayodele, 2002). Heavy metals in soil could be greatly influenced by man mediated activities such as industrial and agricultural activities, waste disposal, etc. (Udosen et al., 1990; Eja et al., 2003; Benson 2004; Zauyah et al., 2004). Pollution is the introduction into the environment of a substance or effect that is potentially harmful or interferes with species habitats (Porteus et al., 1985). The substance that causes pollution is known as pollutant. Heavy metals are of significant environmental concern owing to their relative toxicity and accumulation potentials (Yusuf et al., 2003).
Most abandoned waste dumpsites in many towns and villages in Nigeria are considered as fertile grounds for cultivating varieties of crops. The cultivated plants take up the metals either as mobile ions present in the soil solution through the roots (Davies, 1983)
or through foliar absorption (Chapel, 1986; and Amusan et al., 2005). The uptake of metals by crops results in bioaccumulation of these elements in plant tissues. This is known to be influenced by the metal species, plant species and the part of the plant (Juste and Mench, 1992). Alloway et al., (1971) reported that plants grown on soils possessing enhanced metal concentration due to pollution have increased heavy metal ion content which, if not carefully regulated, may lead to accumulation in man.
Monitoring and systematic gathering of information on heavy metal levels in the environment are essential components of any pollution control system. The establishment of such control system often presupposes the existence of minimum pollution standard and regulations. Most countries within the African sub-region do not have such control standards and environmental impact studies become very imperative. The United State Environmental Protection Agency (USEPA) is a government agency established to enforce the proper disposal of wastes and conduct research in related areas. It reported that 208 millions tons of municipal solid wastes were generated in the United States annually (Luke, 2008). There are many different methods of disposing wastes, these are; land filling, incineration and pumping of wastes into deep wells but there is strong opposition to this method because of the apparent explosions, earthquakes and underground water pollution that may results due to heavy metal pollution (Luke, 2008). Municipal solid waste disposal is an enormous concern in developing countries across the world, as poverty, population growth and high urbanization rates combine with ineffectual and under-funded government to prevent efficient management of wastes (Doan, 1998; Cointreau, 1982). From American perspective, the sheer magnitude of solid waste problem in Nigeria is hard to comprehend as the garbage ―dumps‖ are located on the road sides of highways in cities and town. Since there are no means for containment, wastes
often spread into roads, blocking traffic in many towns and cities in the country (Stephen, 2004). Nigeria is a nation that exemplifies chronic waste management problems in conjunction with population growth. It is the most populous country in Africa with over 140million residents (World Bank, 2002). Over the past 50 years, Nigeria‘s annual growth rate was 5.51% which is the third largest urban growth rate in the world. The Federal government has very little control over environmental regulation as a whole. The Federal Environmental Protection Agency (FEPA) was established in 1988 to control the growing problems of waste management and pollution in Nigeria (Onibokun, 2003). Vision 2010 was FEPA‘s attempt to address environmental problems in the nation. The FEPA report proposed the goals to be accomplished by the year 2010 that would lead toward sustainable development. With regards to solid waste management, the report says the goal is to achieve not less than 80% effective management of the volume of municipal solid wastes generated at all levels and ensure environmentally sound management (Vision 2010, 2003). Strategies to achieve these goals include education and awareness programs, developing collaborative approaches to integrative management of municipal solid waste strengthening existing laws and ensuring compliance and encouraging local and private sector participation. However, poverty and corruption had prevented the implementation of these plans.
Water is the most important substance for human existence (Melese et al.,1998). It is the cradle of life, without which no living thing can survive in this world. Freshwater from rivers, lakes and ground is used to irrigate crops, to provide drinking water, and to act as a sanitation system (Economopoulos, 1993). Frequently, rivers act as conduits for
pollutants by collecting and carrying wastewater from catchments and ultimately discharging it into the ocean and storm water which can also be rich in nutrients, organic matter and pollutants, finds its way into rivers, lakes and other water bodies. Zaria, in Northern Nigeria, with population of over one million four hundred and ninety thousand (1,490,000) that came from different parts of the world faces problems of environmental sanitation such as improper refuse disposal near residential areas, poor refuse collection and handling etc. The environmental pollution posed by solid waste ranged from health hazard to soil and water pollution (Eddy et al., 2006). Some metals are essential components of living systems such as iron in haemoglobin, zinc as an essential component of many enzymes and coenzymes (Nayak, 2000). Respiratory pigments of many mollusks and higher crustaceans contain copper. However, when these metals are present in higher concentrations they accumulate and become toxic to organisms (Nayak, 2000). 1.2 The Research Problem Zaria metropolis is located at latitude 1103′ N and longitude 7 o40’E and is presently one of the most important cities in Northern Nigeria. It has a population of 1, 490,000 people (population census, 2006). Like many cities in Nigeria, Zaria faces problems of environmental sanitation such as improper disposal of refuse near residential areas; poor refuse collection and handling etc. For example, it is common to find huge refuse dumpsites within residential areas and along some minor and major roads (Plate I). City dwellers have long contended that any form of waste with proper composting and processing can be made into fertilizers that farmers will gladly pay for (Amusan et al., 200)
The presence of toxic heavy metals in the environment continues to generate a lot of concern to environmental scientists, government agencies and health practitioners because of health implications of their presence (Awofolu, 2005). Heavy metals have been referred to as common pollutants are widely distributed in the environment with sources mainly from soils and weathering of rocks (Merian, 1991; and O‘ Neil, 1993). However, levels of these metals in the environment have increased tremendously as a result of human inputs and activities (Awofolu, 2005). According to Oskarson et al. (1992), there exist transfer of heavy metals from contaminated soil to plants and from plants to animals with the subsequent transfer through the food chain up to man. It is not uncommon to find ruminants feeding on grasses and birds feed on insects and earthworms on the dumpsite soils. High concentrations of metals in the environment may lead to accumulation, becoming toxic to plants and animals with possible danger to human health.
Plate I: Kusfa (KU) Dumpsite Zaria Metropolis
Solid waste disposal tends to pollute under ground water at the vicinity of dumpsites which has been a serious problem for the entire world. It threatens the health and well-being of the residents, plants, and animals. All water pollution is dangerous to the health of living organisms; it has been reported that the quality of the underground water close to dumpsites is compromised resulting in serious health problems to residents. In some areas, the population has only one source of water and if this water is polluted, the population has no choice but to use it (Ince and Howard, 1999). The effect of toxic substances and a wide range of other adverse effects can occur when waste products are introduced into the water body leading to changes in physical, chemical and biological parameters such as infectious agents, temperature, turbidity, color, pH, salinity and oxygen concentrations. Changes in any of these parameters have direct environmental effects and can also produce impact by modifying other parameters (Chapman, 1992). The role of some heavy metals (Cd and Pb) is very critical in determining the quality of our atmosphere because air, soil and water are directly interacting with each other. Growing heavy metals pollution especially in air has led to increased respiratory diseases, infant mortality and also affects the functioning of the blood, liver, kidney and brain. The measurement of Pb, Cd, Cu, Zn and Ni accumulation in soil and plant appears to be a useful tool for evaluating the potential heavy metal hazards of the environment (Mudassir et al., 2005).
In Nigeria at present, little data is available on the extent of soil-vertebrates-human pollution. Clearly, there is a gap in knowledge related to dumpsite soil-water-animal-human pollution especially in Nigeria and empirical data are needed as the basis for wider modeling assessment.
1.4 Research Questions
The research was aimed to answer the following questions:
i. What are the effects of dumpsites on the air quality at the vicinity of dumpsites
ii. What are the effects of dumpsites on the water quality at the vicinity of the dumpsites
iii. What are the effects of the dumpsites on the soil physico-chemical parameters and heavy metal contents (Zn, Cu, Hg, Cd and Pb). iv. What are the effects of dumpsites on the different organs of the chickens‘ feeding on the dumpsites v. What are the effects of the dumpsites with respect to the particulate dust emanating from the dumpsites vi. What are the effects of the dumpsites on residents with respect to some heavy metal (Zn, Cu, Hg, Cd and Pb) contents. 1.5 Aim and Objectives The aim of this investigation was to assess the dynamics of dust particulates –soil leachates – water – vertebrates – human pollution with special preference to heavy metals (Hg, Cu, Cd, Zn and Pb), and some gaseous pollutants (SO2, NO2, H2S, NH3, flammable gas (Fl) and CO) from dumpsites of Zaria Metropolis, Kaduna State, Nigeria in dry and wet seasons. This aim was designed to be achieved through the following objectives:
i. To Assess quality of the groundwater near the dumpsites in comparison with the standard limits.
ii. To characterize the refuse wastes, determine physicochemical parameters and levels of metals in the soils and leachates using sequential extraction method.
iii. To assess the quality of the air around the dumpsites and compare it/them to standard limits.
iv. To determine the concentrations of the heavy metals in the tissues and organs of chickens fed with the refuse wastes.
v. To determine the concentrations of the afore mentioned heavy metals in blood, nails, hair and urine samples of people living at the vicinity of dumpsites across the seasons.
vi. To develop a bismuth electrode (BiEs) and ascertain its workablity compared to other analytical methods for the determination of heavy metals in water samples.
1.6 Research Hypotheses The study was guided by the following hypotheses:
i. The null hypotheses (H0) states that
a. the water quality at the dumpsites is not significantly different from that at the control site
b. the air quality at the dumpsites is not significantly different from that at the control site
c. there is no significant difference in the physico-chemical parameters and heavy metal contents between soils from dumpsite and those of the control site
d. there is no significant difference between the heavy metals in chickens‘ tissues and organs fed with the refuse waste and those at the control site.
e. there is no significant difference between heavy metals in human blood, nail, hair and urine collected from people living at the vicinity of the dumpsites and those from the control site.
f. there is no significant difference between square wave technique and the atomic absorption spectrometry
ii. the alternative hypotheses (H1), which states that there is significant differences in a, b, c, d and e.
1.7 Significance of the Study In Zaria metropolis, little data is available on the extent of soil – vertebrates – human pollution around the dumpsites. A variety of metal ions and hazardous gaseous pollutants demonstrate a wide range of uptake capacities and interaction mechanisms as reported in literatures from developed countries. Clearly, there is a gap in knowledge related to dumpsite soils – water – animals – human pollution especially in Nigeria, a developing country. Therefore, an empirical data is needed as the basis for wider modeling assessment which forms the basis of this research. 1.8 Scope and Limitations The study was designed to assess the impact of dumpsites in Zaria Metropolis and their environments to include air, soil, water, leachates, animals, birds and human kind across the four seasons of the year in 10 dumpsites and a control site. However, during the sampling, it was obvious that the research could not be sustained for the four seasons due to finance, hence, the research was limited to two seasons (dry and wet ) of the year.
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