CHAPTER ONE
INTRODUCTION
1.0 BACKGROUND OF THE STUDY
Water is a valuable resource, which is not only vital in sustaining life, but is also important in the functioning of our society. Water is used in domestic activities such as cooking, cleaning and washing. It is also used in agriculture, as drinking water for livestock and in irrigation. It functions in industry in the running of machinery, cooling hot metals. It can also be used in generation of electricity. As a chemical compound, water molecule contains two atoms of hydrogen and one atom of oxygen linked by a covalent bond. At ambient temperature and pressure, water exists as liquid. A change in temperature makes it solid or gaseous. Clean water is needed for drinking and recreation.
Our drinking water today, far from being pure, contains some two hundred deadly commercial chemicals. Add to that bacteria, viruses, inorganic minerals and chemicals unsuitable for human consumption (Acher, 1996). The battle against water pollution may not be successful if other earth component is not tackled. Water is referred to as polluted when it is impaired by anthropogenic contaminants and either does not support human use, or undergoes a marked shift in its ability to support its constituent biotic communities. It has been suggested that water pollution is the leading worldwide cause diseases and deaths (Pink, 2006 and West, 2006).
There are basically two types of water resources. These are surface water and groundwater. Water collected on the surface of the earth constitutes the surface water. It is naturally open to the atmosphere and includes water from estuaries, ponds, lakes, reservoirs, streams, rivers, ocean and seas. Water collected beneath the earth’s surface in soil pore spaces and fracture or rock formation is termed groundwater. Such units of rock are referred to as aquifers when they can yield a usable quantity of water (Greenburg, 2005). Various organic and inorganic pollutant render water unsafe for life. Heavy metals contaminates both surface and ground water. These pollutant in water have serious detrimental effect on humans and the ecosystems that rely on it. Although these pollutants may occur naturally but are rare and often comes from anthropogenic sources.
1.1 BACKGROUND OF THE STUDY
Water is a valuable resource. It has the chemical formula (H2O). It is a transparent fluid which forms the world streams, lakes, oceans and rains, and this is the major constituent of the fluid in living things. Water covers 71% of the earth’s surface, 96.5% of the planet’s water is found in seas and oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of antarctica and Greenland, small fraction in other large water bodies, and 0.001% in the air as vapour, clouds, and precipitation (Gleick, 1993).
Water is very vital in agriculture (the most important use of water in agriculture is for irrigation which is a key component to producing enough food .irrigation takes 90% of water withdrawn in some developing countries and significant proportion in some more economically developed countries. Water here is also use in livestock rearing. ), municipal (water for domestic usage and commercial water such as water use in hotels, office buildings, civilian and military institutions), and industrial (processing, dilution, transportation, and cooling in manufacturing facilities) use. Pollution can mar the availability and potability of water use and supply.
1.2 WATER POLLUTION
Water pollution is the contamination of natural water bodies by chemical, physical, radioactive or pathogenic microbial substances. (Hogan 2014). Adverse alteration of water quality presently produces large scale illness and deaths accounting for approximately 50 million deaths per year worldwide, most of these deaths occurring in Africa and Asia. In china, for example, about 75% of the population are without access to unpolluted drinking water, according to china’s own standards (Charles, 2002).
In addition to the acute problems of water pollution in developing countries, developed countries also continue to struggle with pollution problems, for instance, in a recent national report on water quality in the United States, 45% of assessed stream miles, 47% of assessed lake acres, and 32% of assessed bays and estuarine square miles were classified as polluted (US –EPA, 2007 National Water quality Report). The head of China’s national development agency said in 2007 that one quarter the length of China’s seven main rivers were so poisoned, such that the water harmed the skin (Wachman, 2007).
1.2.1 Sources of Water Pollution
There are two different sources of pollution, and these are:
- point source of pollution, and
- non point source of pollution.
Point source of pollution
It is a pollution that comes from a single source or location such as a discharged attached to a factory, an oil spill from a tanker, (US-EPA, 2010) or pollution from municipal water treatment plants.(National Water Quality Monitoring Council, 2007).
Non point source of pollution
This is a source of water pollution that does not come from a single source such as snowmelt or rainfall picking up natural or anthropogenic pollutants and depositing them into water resources. Examples include pollutants from urban runoff, poorly managed construction sites, irrigation practices, abandoned mines and livestock operations.
1.2.2 Types of Water Pollution
The earth’s water resource is of two forms; surface water (water from oceans, lakes, rivers, etc) and underground water (held in underground water structure known as aquifers). Surface water and Ground water are the two types of water resources that pollution affects (Woodford, 2015).
Surface Water Pollution
This is the most visible form of water pollution and it can be seen floating on waters in lakes, streams, oceans. Trash from human consumption such as plastics, oil spill is most often evidence on water surfaces. This type of pollution also comes from oil spills and gas pipeline waste, which float on the surface and affects the water and its inhabitants
Groundwater Pollution
This is usually caused by highly toxic chemicals and pesticides from farming that leaks through the ground to contaminate the wells and aquifers below the surface. A groundwater pollutant is any substance that when it reaches an aquifer, makes water unclean or otherwise unsuitable for a particular purpose. Sometimes the substance is a manufactured chemical, but just as often it might be microbial contamination. Contamination also can occur from naturally occurring mineral and metallic deposits in rock and soil.
For many years, people believed that the soil and sediment layers deposited above an aquifer acted as a natural filter that kept many unnatural pollutants from the surface from infiltrating down to groundwater. By the 1970s, however, it became widely understood that those soil layers often did not adequately protect aquifers. Scientists have since realized that once an aquifer becomes polluted, it may become unusable for decades, and is often impossible to clean up quickly and inexpensively (Mason, 2003).
Oil Pollution
Over 70% of oil pollution at sea comes from routine shipping and from the oil people pour down drains on land (Kennish, 2009) only 12% of the oil that enters the oceans comes from tanker accidents. However, what makes tanker spill so destructive is the sheer quantity of oil they release at once. (IMO: Marine Environmental Awareness, 2011).
Chemical Waste Pollution
Detergents are relatively mild substances, at the opposite end of the spectrum are very toxic chemicals such as polychlorinated bis-phenyls (PCBs). They were once used to manufacture electronic circuit boards, but their harmful effects have now been recognized and their use is highly restricted in many countries. Nevertheless, an estimated half million tons of PCBs were discharged into the environment during 20th century (Robertson et al., 2015). Although PCBs are widely banned, their effects will be felt for many decades because they last a long time in the environment without breaking down (Woodford, 2015).
Another kind of toxic pollution comes from heavy metals such as lead (Pb), cadmium (Cd), mercury (Hg), etc. Lead was once commonly used in gasoline (petrol), though its use is now restricted in some countries. Mercury and cadmium are still used in batteries i.e. Nickel-Cadmium battery. The best known example of heavy metal pollution in the ocean took place in 1938 when a Japanese factory discharged a significant amount of mercury metal into Minamata Bay, contaminating the fish stocks there. It took a decade for the problem to come to light. By that time, many local people ate the fish and about 2000 were poisoned, hundreds of people were left dead or disabled (Kosei, 1982).
Oxygen Depletion Pollution
Micro-organism that lives in water feeds on biodegradable substances. When there is an influx of biodegradable material from such things as waste or erosion, the number of these organisms increase and utilize the obtainable oxygen. When these oxygen levels are depleted, harmless aerobic microorganisms die and anaerobic microorganisms thrives. Some of these organisms produce damaging toxins like sulfide and ammonia (Hearn, 2014).
Agricultural Pollution
Agriculture is the modification of the landscape for production of goods that are used for sustenance or market. It includes forestry, crop culture, biomass production for fuel and animal husbandry (Moss, 2007). Impacts on water and marine systems refers to the result from agricultural change of the landscape. This may include effects on water chemistry (Agouridis et al., 2005). Nitrogen and phosphorus leached from fields or animal dung have exactly the same effect as those produced by street drainage. Just as agriculture has comprehensively changed the face of the earth, its impacts have equally profoundly re-wrought the nature of its waters.
1.2.3 Causes of Water Pollution
Sewage
Sewage disposal affects people’s immediate environments and leads to water related illnesses such as diarrhea which kills about 760,000 children under five each year (WHO, 2013). The sewage water carries harmful bacteria and chemicals that can cause serious health problems. In theory, sewage is a completely natural substance that should be broken down harmlessly in the environment; 90% of sewage is water. In practice, sewage contains all kinds of other chemicals, from the pharmaceutical drugs people take to the paper, plastics, and other wastes that is flush down from the toilets. When people with viruses discharge their waste into sewage, the sewage produce carries those viruses into the environment. It is possible to get sickness such as hepatitis, typhoid, and cholera from river and sea water.
Waste Water
This include chemicals washed down the drains and discharged from factories. About half of ocean pollution is caused by sewage and waste water. Each year, the world generates perhaps 5-10 billion tons of industrial waste, much of which is pumped untreated into rivers, ocean, and other water ways (Spalding et al., 1998). Factories are point sources of water pollution, but quite a lot of water sources are polluted by humans from non-point sources. Virtually every one discharges chemicals of one sort or another down their drains. Generally, detergents used in daily washing and pesticides and fertilizers used in the gardens eventually end up in our rivers/oceans (www.explainthatstuff.com/water pollution.html). Oil spill constitutes a huge problem as large amount of oil enters the sea through pipeline leakages and does not dissolve with water thereby posing problem for man, and local marine wildlife such as fish, birds, and sea otters.
1.2.4 Effects of Water Pollution
The effects of water pollution in world re socio-economic, health and environmental problems. Children and new born babies are mostly affected by water pollution as can be seen from the infant mortality rate. Water related diseases such as malaria, cholera, and guinea worm infection are most common causes of illness and death. Heavy metal poisoning is also a serious health and environmental problem resulting from absorption in contaminated water (Ijaiya, 2013).
Level of toxicity of water depends on the type of pollutant. Mercury is reported to cause impairment of brain functions, neurological disorders, and retardation of growth in children, abortion and disruption of endocrine system. Pesticides are generally toxic or carcinogenic, damaging the liver and nervous systems. High fluoride content is often detected from symptoms such as yellowing of teeth, damage joints and bone deformities, which occurs from 10 years of exposure to fluoride containing water. Arsenic contamination of drinking water causes a disease called arsenicosis, for which there is no effective treatment, though consumption of arsenic free water could help affected people at early stages of the ailment to get rid of the symptoms of arsenic toxicity (Kumar et al., 2003).
1.3 JUSTIFICATION OF THE STUDY
Incessant digging of borehole/well and subsequent infiltration of pollutant into the aquifer is posing threats to health and potability of groundwater. As such, the result from this work would help in informing the people of these areas on the quality of their underground water resource. There is limited research and environmental data available for continuous assessment of groundwater quality in these areas. This work therefore will provide information and serve as a valuable reference material for future analytical work.
1.4 AIMS AND OBJECTIVES OF THE STUDY
Excessive withdrawal of groundwater from aquifers has lead to induced pollution in the form of intrusion. As such, this study is aimed at determining the physical/chemical characteristic of groundwater in some designated communities in Ikono and Ini LGA, levels of trace elements in the study area, concentration of some inorganic anions (nutrient), and determining compliance of water quality parameters with regulations/standards
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