REVIEW OF LITERATURE
2.1 INTRODUCTION
Our focus in this chapter is to critically examine relevant literature that would assist in explaining the research problem and furthermore recognize the efforts of scholars who had previously contributed immensely to similar research. The chapter intends to deepen the understanding of the study and close the perceived gaps.
Precisely, the chapter will be considered in three sub-headings:
Conceptual Framework and
Theoretical Framework
Empirical Review
2.1 CONCEPTUAL FRAMEWORK
Concept of Pollution
Pollution is the introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resource as ecological damage; or interference with legitimate uses of the environmental (Millar, 1998). Environmental pollution according to Miller (1998) is “any addition to air, water, soil or food that threatens the health, survival or activities of human or other living organism”. Such chemical or form of energy that causes harm is called pollutant. The pollutants can be solid, liquid, or gaseous products or wastes produced when a resource is extracted, processed, made into products or used. Equally, it can take the form of unwanted energy emissions, such as excessive heat or radiation (Miller Supra).
Similarly, Moronkola, (2003) states that the United Kingdom‟s Protection of Environment Act (1990) declares pollution of the environment as what is released into any environmental medium as a result of human activity which is capable of causing harm to human or other living organisms supported by the environment.
One of the greatest problems that the country is facing today is that of environmental pollution emanating from oil exploration, extraction and related activities. Environmental pollution of the physical environment is of three basic types, namely; air pollution, water pollution and soil \ land pollution.
Pollution is simply the introduction of contaminants into the natural environment that could alter the normal occurrences or distort the orderliness of the system. Pollution was also defined by the European Union 1996 Council Directive on Integrated Pollution Prevention and Control (IPPC) as “the direct or indirect introduction as a result of human activity, of substances, vibrations, heat or noise into the air, water or land which may be harmful to human health or the quality of the environment, result in damage to material property, or impair or interfere with amenities and other legitimate uses of the environment” (Gbehe, 2004).
Concept of Water
Ugeh (2009) stated that water is one of the renewable resources essential for sustaining all forms of life, food production, economic development, and for general well being. It is impossible to substitute for most of its uses, difficult to depollute, expensive to transport, and it is truly a unique gift to mankind from nature. Water is also one of the most manageable natural resources as it is capable of diversion, transport, storage, and recycling. All these properties impart to water its great utility for human beings. The surface water and groundwater resources of the country play a major role in agriculture, hydro power generation, livestock production, industrial activities, forestry, fisheries, navigation, recreational activities etc (Water Management Forum. 2003). The freshwater ecosystems of the world comprise only about 0.5% of the earth’s surface and have a volume of 2.84x105 Km3. Rivers constitute an insignificant amount (0.1%) of the land surface. Only 0.01% of the waters of the earth occur in river channels. Inspite of these low quantities, running waters are of enormous significance (Wetzel, 2001). Out of this, monsoon rainfall is of the order of 3000 km3. Rainfall in Nigeria is dependent on the south-west and north-east monsoons, on shallow cyclonic depressions and disturbances and on local storms (Kumar et. al., 2005). Most of it takes place under the influence of south-west monsoon between March and September (Kumar et. al., 2005). Nigeria is gifted with river system comprising of many rivers with several tributaries. Many of these rivers are perennial and some of them are seasonal.
In the last few decades, there has been a tremendous increase in the demand for freshwater due to rapid growth of population and the accelerated pace of industrialization (Ramakrishnaiah et al., 2009). Human health is threatened by most of the agricultural development activities particularly in relation to excessive application of fertilizers and unsanitary conditions (Okeke & Igboanua, 2003). Anthropogenic activities related to extensive urbanization, agricultural practices, industrialization, and population expansion have led to water quality deterioration in many parts of the world (Baig et al.2009, Mian et al., 2010, Wang et al., 2010). In addition, deficient water resources have increasingly restrained water pollution control and water quality improvement (Bu et al., 2010). Water pollution has been a research focus for government and scientists. Therefore, protecting river water quality is extremely urgent because of serious water pollution and global scarcity of water resources.
Water Resources in Nigeria
Accessibility to plentiful water resources in Nigeria is widespread throughout the sub-saharian country. This capital of water is a primary measure used in the development of all life aspects like industry, agriculture and human consumption. According to Okeke & Igboanua, (2003), these water assets can be classified into two categories in general.
Fresh surface water:
It constitutes approximately 80% of the country’s water, and includes ocean provenance, evenly distributed rivers and streams, lakes, water basins and wetlands. Annual rainfall varies along the latitude of the country from around 250mm in the extreme north to about 500mm in the south (Aminu 2000 ; CBN 2000, citied in Orubu 2006).
Groundwater:
There is an excessive quantity of water stored in Nigeria’s underground aquifers sited in several hydrological districts adjacent to major rivers. Yield at these sources fluctuates from 0.7 to 37.0 liters per second according to the location. (Kundell 2008).
Vast applications in the ecosystem depend fundamentally on water as a vital supply for development and universal existence and continuity. According to - the Food and Agriculture Organization of the United Nations – FAO (2009); more than 68% of the total water withdrawal in Nigeria is used for the agriculture sector which includes irrigation and livestock, and 21% as municipal water withdrawal as of the year 2000 evaluation.
The ultimate use of water is effective in its pure condition; however, contaminated water adversely affects habitation. In reality, Nigeria is one of the countries that have polluted water as explained later in this assignment. FAO (2005) recorded that only 60% of the total population had access to safe drinking water in 2002. The problem is more serious in the rural area as 51% of the citizens live without safe drinking water.
History of Water Pollution
Ancient Times:
Water forms like rivers, lakes and streams were in the ancient times the source of drinking water. However, human waste was deposited in the same water bodies. Therefore, in rivers became so polluted that in order to obtain clean drinking water, these ancient cultures needed to build aqueducts (FAO 2005). The main cause for polluted water was that its way to rivers and streams that were originate by human waste.
Medieval Times—1800s:
During this time, people were unaware of what was good for them and what was bad. Mercury was frequently dumped into water and was allowable to run freely into lakes and streams from most of the humans and farm waste. Most people living in metropolises just dumped their waste and garbage onto the street that smelled very bad, probably.
Civilization made many great strides during the latter half of this period, frequently to the damage of the ecosystem. Individuals even consumed chemicals at that time as they thought, it’s good for their health. For the benefit of industry, the Industrial Revolution of the 1800s saw little care for the ecological impact. Many chemical substances have been dumped into the rivers. At that time, people were not concerned about the environmental impact of their inventions (Gleick 2002).
After World War-II: Besides contaminants such as human waste, composts, leather tanning and slaughtering waste, the development of industries and factories had also resulted in much water pollution problems. As waste from industries dumped into river freely without care about the environment were affecting ecology and humans, including flora and fauna (Jeantheau 2005).
1969: After a series of fires on the Cuyahoga River in 1969, it was realized that fires were triggered by oil slicks and dumped into it by flammable industrial waste. According to Gleick (2002), the government then began the studies that allowed the 1972 Clean Water Act to be enacted.
Present Day: Many people still do not know how to guard themselves against chemical toxins and waterborne diseases, even with this act. Many cleanups on a large scale have been going on for years.
Water Pollution
Water is regarded as polluted when there is change in its quality or composition, either directly or indirectly, as a result of both natural and human activities, such that it becomes unsuitable for domestic uses, agricultural, fisheries or any other purposes for which it would otherwise be quite suitable in its normal or uncontaminated state (Larry, 2006). One of the most important needs of living things is water because of its significance to human and other biological organisms. After air, water is the most vital requirement for sustainance of life. Pollution in a natural way is not very serious with water, as the pollutants get assimilated by water. Water pollutants bring about physical and chemical changes not only in the surface water, but also in the ground water.
Water is not suitable for consumption if it has biological organisms like guinea worms, tape worms, cholera and typhoid-creating bacteria and excess chemicals such as fluoride, iron, arsenic and nitrate. The pollutants are usually pathogens, silt and suspended solid particles such as soils, sewage materials, disposed foods, cosmetics, automobile emissions, construction debris and eroded banks of rivers and other waterways (Larry, 2006). Some of these pollutants are decomposed by the action of micro-organisms through oxidation and other processes.
Pollution that affects water comes mainly from industries, farms and sewage systems Kundell (2008), but in developing nations, water becomes polluted from the sources after pumping. The common sources of water that are available to local communities in Nigeria are fast being severed by a number of anthropogenic factors, of which pollution remained the most dominant problem.
There is a closer link between pollution and health damages. Five million people die each year because of polluted drinking water, poor sanitation and domestic unhygienic around the world (Maier 1993). In African countries, Nigeria in particular, water related diseases had been interfering with basic human development. There are numerous scientific and economic facts that water shortage or its pollution can cause severe decrease in productivity and death of living species. In Nigeria today research indicated that majority of the common fresh water sources are polluted, resulting in serious outbreak of diseases. The major issues of national and international interest are how these water pollution problems could be fully assessed and mitigated. Proper knowledge and planning are thus essential (Mathiason 2009).
In 2005, the National Council on Water Resources (NCWR) recognized the need to urgently establish acceptable Nigerian standard for drinking water quality because it was observed that the “Nigerian Industrial Standard for Potable Water” developed by Standards Organization of Nigeria and the “National Guidelines and Standards for Water Quality in Nigeria” developed by Federal Ministry of Environment did not receive wide acceptance by all stakeholders in the country. Since water quality issues are health related issues, the Federal Ministry of Health, collaborating with the Standards Organization of Nigeria and working through a technical committee of key stakeholders developed standards for effective protection of public health against water related diseases and standards for protection of water sources from potential sources of contamination.
Origin of Water Pollution
The origin of pollutants can be attributed to their fundamental occurrence on earth, the development of natural products by transformation, and their man-made syn- thesis. The particulates might well arise indeed very naturally to form part of the ecological background exposure levels Many of them are excreted by the organ- isms or detoxified. Examples of some pollutants that occur naturally are nitrogen oxides, heavy metals. Hydrocarbons and substances that are radioactive (Odeh 2006).
Some pollutants can be formed during their domestic, agricultural or industrial use by concentration and transformation of naturally occurring compounds. The generation of sewage and waste waters comprising agrochemicals, pesticides, petrochemicals hydrocarbons, heavy metals, and radio nuclides are some important examples of pollutants that have emerged from this.
Many of the chemicals do not occur in the nature and the pollution they cause is entirely man-made. For example, the synthesis of various pesticides, surfactants, plastics and petrochemicals has created a large number of chemicals in the envi- ronment that have created serious environmental problems (Odeh 2006).
Sources of Water Pollutants
The major sources of water pollution that result in contamination are direct and indirect ones, in addition to other sources.
Direct pollution is caused by releasing fluids directly into the water, such as a company that expels contaminated water or toxic solids mixed directly with water into the sea or river. This makes the water poisonous, every so often resulting in death, for fish and other aquatic creatures. Nevertheless, animals also drink this water, which also bring to them ill health or death. It can also affect to humans. In developed countries, people no longer depend on drinking water from the stream or river. There is still a risk for those who swim in or participate in activities such as canoeing on polluted water, as some of them can cause illness and even death (Obayomi 2009).
Indirect water pollution is not caused by the introduction of contaminants directly into the water, but by those that end up there. An example includes fertilizer and pesticide chemicals that are washed slowly through the soil and find their way into groundwater and then into various watercourses. In addition, air pollution can cause acid rain to fall to the ground, which can be extremely harmful to wildlife, including polluting lakes, streams and shores, and make the water deadly for those creatures that leave in and near it (Obayomi 2009).
Whether it’s direct or indirect water pollution, the results can still be the same, i.e. disease and possibly death to any living thing that lives in it or takes in water. Therefore, it is imperative that individuals and businesses take steps to reduce their levels of pollution and reduce their environmental impact
Types of Water Pollutants
According to Musa (2013), there are various types of pollutants categorized as:
Organic Pollutants
Inorganic Pollutants
© Radioactive Pollutants
Suspended Solid
Pathogens
Nutrients and Agricultural Pollutants
Thermal Pollution.
These pollutants are described as follows:
Organic Pollutants
Organic compound consists of carbon, hydrogen, oxygen, nitrogen and Sulphur. Organic compound emitted from sewage, urban waste water, industrial wastewater and agricultural waste. Example is Oleic acid, Palmitic acid, Dodecanoyl chloride and Docosanoic anhydride (Musa 2013).
Inorganic Pollutants
Developing countries are concerned about contamination of harmful chemicals such as nitrite, ammonium nitrate and heavy metals in drinking water. The high levels of inorganic nitrogen pollutants (nitrate, nitrite, ammonium) and inorganic phosphates in river water resulting from draining water from agricultural fields, releasing municipal/industrial sewage, etc. lead to many health problems. Nitrite is car- cinogenic in nature, which increases the risk of stomach, liver and esophageal cancer and can lead to high levels of ammonium in the body (Musa 2013).
Radioactive Pollutants
Naturally radioactive material comes from earth crust and dissolves in surface drinking water. Anthropogenic radioactive material emitted from nuclear power plant, nuclear weapons testing and manufacture and application of radioactive material. Generally, radionuclide appeared in drinking water have series of ura- nium, thorium and aluminum and with naturally occurring materials of radium, uranium and the radioactive gas radon. These contaminants cause dangerous effect on human being. Radium causes bone cancer. Uranium also causes cancer in bone and toxic effect on kidney (Musa 2013).
Suspended Solid
Suspended solid are the pollutants municipal and industrial wastewater treatment plants and sewage treatment plants. There are three different types of suspended solid are found (a) sand and other material at washing steps (b) organic content that cannot used for final product (c) suspended solid in the wastewater.
Pathogens
Pathogens are small microbes that cause disease, including bacteria, viruses, pil- lows, and certain parasites. Viruses generally present in wastewater are Hepatitis and Norwalk virus and a common fungus is Candida. A salmonella bacterium causes food poisoning whereas Vibrio cholera is the pathogen that causes cholera. Parasites such as Cryptosporidium and Schistosoma can cause diarrhea and all wastewater pathogens can lead to serious gastrointestinal illness (Musa 2013).
Nutrients and Agricultural Pollutants
As a result, the use of large quantities of chemical fertilizers in agriculture causes so many environmental problems as some fertilizers contain heavy metals (e.g. cad- mium and chromium) and high radionuclide concentrations. Non-organic fertilizer contains salts of phosphate, nitrate, ammonium and potassium. Manufactured fer- tilizer industry contains excess heavy metals such as Hg, Cd, As, Pb, Cu, Ni, and Cu. Heavy metal fertilizer is deposited in the soil and plant system. Plants absorb fertilizers through the soil; they can enter the food chain that contaminates the water (Musa 2013).
Thermal Pollution
The temperature alteration in water bodies, as a result thermal pollution occurs. The thermal power plants discharge causes raise in temperature of aquatic system of 10 °C. Therefore, very serious effect on aquatic life due to global warms by thermal effect. Use of wind and solar energy in place of thermal energy. Thermal pollution decreases by plantation and reduce the emitting of carbon dioxide in environment
Types of water pollution
Surface water:-
Water resources like huge oceans, lakes, and rivers etc. are called surface waters. Contaminants such as chemicals, nutrients, and heavy metals are carried from farms, factories, and cities into streams and rivers and then to seas and oceans. Our seas are also sometimes spoiled by oil spills Milieu (Defensie 2008).
Ground water:-
Water stored underground in aquifers is known as groundwater. Groundwater gets polluted when contaminants (pesticides, fertilizers) or waste leached from landfills and septic systems make their way into an aquifer, rendering it unsafe for human use. It is virtually impossible to remove contaminants from groundwater. Groundwater can also spread contamination into streams, lakes, and oceans (Defensie 2008).
Sources of water pollution:
Water pollution can occur from two sources.
Point source and
Non-point source.
According to WHO (2005), point sources of pollution are those which have direct identifiable source. Example includes pipe attached to a factory, oil spill from a tanker, effluents coming out from industries. Point sources of pollution include wastewater effluent (both municipal and industrial) and storm sewer discharge and affect mostly the area near it. Whereas non-point sources of pollution are those which arrive from different sources of origin and number of ways by which contaminants enter into groundwater or surface water and arrive in the environment from different non identifiable sources. Examples are runoff from agricultural fields, urban waste etc. Sometimes pollution that enters the environment in one place has an effect hundreds or even thousands of miles away (WHO 2005). This is known as transboundary pollution. One example is the radioactive waste that travels through the oceans from nuclear reprocessing plants to nearby countries. Water pollutants may be i) Organic and ii)Inorganic water pollutant.
Organic water pollutants: They comprise of insecticides and herbicides, organohalides and other forms of chemicals; bacteria from sewage and livestocks farming; food processing wastes; pathogens; volatile organic compounds etc (Unicef 2007).
Inorganic water pollutants: They may arise from heavy metals from acid mine drainage; silt from surface run-off, logging, slash and burning practices and land filling; fertilizers from agricultural run-off which include nitrates and phosphates etc. and chemical waste from industrial effluents (WHO 2005).
They can also be classified into natural and man-made sources
Natural Sources and Runoff
The natural entry of pollutants in water reservoirs can be done through various activities as given below.
Rain water
Atmosphere (dust, storms)
Underground rocks and volcanoes
Natural run off
Surrounding vegetation
WHO (2005) states that rain water is an important natural source of water pollution, which dissolves the pollutants from air and brings down the entrained particulate matter with it. E.g. Occurrence of acid rain formed due to the dissolution of acid gases such as oxides of Sulphur and nitrogen in rainwater. The direct deposition of particulate by gravity is called dry deposition is another way of causing water pollution.
The falling of leaves, twigs and other parts of surrounding vegetation can also enrich waters. Presence of underground rocks and volcanoes beneath the water bodies may also be the source of certain kinds of salts (WHO 2005).
Man-made sources
Domestic Sewage
Domestic Sewage comprises of waterborne wastes of the public and contains about 99% of water and 1% of solids. Of the solids existing in sewage, 70% are organic and 30% are inorganic in nature. Out of the organic constituents 65% are proteins, 25% carbohydrates and 10% fat. Inorganic fraction of sewage constitutes grit, salts and metals in varying proportions.
Urbanization: Urbanization generally leads to higher phosphorus concentrations in urban catchments (Paul & Meyer, 2001). Increasing imperviousness, increased runoff from urbanized surfaces, and increased municipal and industrial discharges all result in increased loadings of nutrients to urban streams. This makes urbanization second only to agriculture as the major cause of stream impairment.
Sewage and other Oxygen Demanding Wastes: Management of solid waste is not successful due to huge volumes of organic and non-biodegradable wastes generated daily. As a consequence, garbage in most parts of India is unscientifically disposed and ultimately leads to increase in the pollutant load of surface and groundwater courses. Sewage can be a fertilizer as it releases important nutrients to the environment such as nitrogen and phosphorus which plants and animals need for growth. Chemical fertilizers used by farmers also add nutrients to the soil, which drain into rivers and seas and add to the fertilizing effect of the sewage. Together, sewage and fertilizers can cause a massive increase in the growth of algae or plankton that facilitate huge areas of oceans, lakes, or rivers creating a condition known as algal bloom thereby reducing the dissolved oxygen content of water and killing other forms of life like fish (Defensie 2008).
Industrial Wastes: Many of the industries are situated along the banks of river such as steel and paper industries for their requirement of huge amounts of water in manufacturing processes and finally their wastes containing acids, alkalies, dyes and other chemicals are dumped and poured down into rivers as effluents. Chemical industries concerning with manufacture of Aluminium release large amount of fluoride through their emissions to air and effluents to water bodies. Fertilizer industries generate huge amount of ammonia whereas steel plants generate cyanide. Chromium salts are used in industrial process for the production of sodium dichromate and other compounds containing chromium. All such discharges finally arrive at water bodies in the form of effluents affecting human health and the organism living there (Defensie 2008).
Agro-chemical Wastes: In the agricultural sector, water and electricity for irrigation are subsidized for political reasons. This leads to wasteful flood irrigation rather than adoption of more optimal practices such as sprinkler and drip irrigation. Cropping patterns and farming practices also do not necessarily encourage the judicious use of water. There are losses of water due to breaches and seepage resulting in water logging and salinity. Agro-chemical wastes include fertilizers, pesticides which may be herbicides and insecticides widely used in crop fields to enhance productivity. Improper disposal of pesticides from field farms and agricultural activities contributes a lot of pollutants to water bodies and soils. Some of the pesticides are: DDT, Aldrin, Dieldrin, Malathion, Hexachloro Benzene etc. Pesticides reach water bodies through surface runoff from agricultural fields, drifting from spraying, washing down of precipitation and direct dusting and spraying of pesticides in low lying areas polluting the water quality. Most of them are non-biodegradable and persistent in the environment for long period of time. These chemicals may reach human through food chain leading to biomagnification (Defensie 2008).
Nutrient enrichment: The sources of nutrients in surface water can be divided broadly into natural and anthropogenic types. Contribution to pollution by natural source is low due to balance established by the natural system between the production and consumption of nutrients over the course of time. Anthropogenic sources of contaminants are contributed from agriculture, domestic and industrial wastes. Nutrient concentrations in streams and rivers have been strongly correlated with human land use and disturbance gradients. Both N and P enrichment have links with the agricultural and urban land uses in the watershed. Fluxes of total N in temperate-zone rivers surrounding the North Atlantic Ocean are highly correlated with net anthropogenic input of N in their watersheds (Howarth et al., 1996). Total N and nitrate fluxes and concentrations in rivers are also correlated with human population density (Howarth et al., 1996). Nitrogen fertilization is the main source of N in streams and rivers (Goolsby and Battaglin, 2001). Similarly, nutrient enrichment of aquatic systems from anthropogenic sources includes point and non point sources (Carpenter et al., 1998). In contrast to point sources of nutrients that are relatively easy to monitor and regulate, non point sources such as livestock, crop fertilizers, and urban runoff exhibit more spatial and temporal variability. Following strong regulation of point source inputs in response to the Clean Water Act, nutrients from nonpoint sources are now the major source of water pollution in the United States (Carpenter et al., 1998).
Thermal pollution: Changes in water temperature adversely affect water quality and aquatic biota. Majority of the thermal pollution in water is caused due to human activities. Some of the important sources of thermal pollution are nuclear power and electric power plants, petroleum refineries, steel melting factories, coal fire power plant, boiler from industries which release large amount of heat to the water bodies leading to change in the physical, chemical and biological characteristics of the receiving water bodies. High temperature declines the oxygen content of water; disturbs the reproductive cycles, respiratory and digestive rates and other physiological changes causing difficulties for the aquatic life (Royal & Parvez. 2015).
Oil spillage: Oil discharge into the surface of sea by way of accident or leakage from cargo tankers carrying petrol, diesel and their derivatives pollute sea water to a great extent. Exploration of oil from offshore also lead to oil pollution in water. The residual oil spreads over the water surface forming a thin layer of water-in-oil emulsion.
The disruption of sediments: Construction of dams for hydroelectric power or water reservoirs can reduce the sediment flow affecting adversely the formation of beaches, increases coastal erosion and reduces the flow of nutrients from rivers into seas (potentially reducing coastal fish stocks). Increased sediment flow can also create a problem. During construction work, soil, rock, and other fine powders sometimes enter nearby rivers in large quantities, causing water to become turbid (muddy or silted). The extra sediment can block the gills of fish, causing them suffocation (Royal & Parvez. 2015).
Acid rain pollution: Water pollution that alters a plant’s surrounding pH level, such as due to acid rain, can harm or kill the plant. Atmospheric Sulfur dioxide and nitrogen dioxide emitted from natural and human-made sources like volcanic activity and burning fossil fuels\interact with atmospheric chemicals, including hydrogen and oxygen, to form sulfuric and nitric acids in the air. These acids fall down to earth through precipitation in the form of rain or snow. Once acid rain reaches the ground, it flows into waterways that carry its acidic compounds into water bodies. Acid rain that collects in aquatic environments lowers water pH levels and affects the aquatic biota (Royal & Parvez. 2015).
Radioactive waste: Radioactive pollution is caused by the presence of radioactive materials in water. They are classified as small doses which temporary stimulate the metabolism and large doses which gradually damage the organism causing genetic mutation. Source may be from radioactive sediment, waters used in nuclear atomic plants, radioactive minerals exploitation, nuclear power plants and use of radioisotopes in medical and research purposes.
Chemical and Industrial Pollution
Water can simply host the chemical substances due to its particular physical and chemical properties (World Bank 2009). Chemical and industrial disposals are frequent pollutants of the water as they have the ability to dissolve in the water molecules. Nevertheless, chemical pollutants either as solution in the atmosphere or as a direct discharge from factories have few broad groups are discussed below according to their effects.
An obvious example is the disposal of industrial waste into the lagoon from Lagos metropolis which adversely affected the aquatic life and the aesthetic view of the metropolis (Onaji 1989, cited in Adedeji & Ako 2008). Hence, bluish green is the current colour of the affected water, their potential hydrogen (PH) level is high, and the meant rivers have non-preferable sodium and lead components (Odeh 2006, cited in Adedeji & Ako 2008).
Pesticides: as part from insects killing in farms and suburbans, pesticides are used in Nigerian states (see Figure 6). Pesticides reach and contaminate both surface water and ground water via runoff
– with rain or irrigation water - from adjacent farmlands, roadsides or countryside lawns (Jeantheau 2005 and 2009). Usually, pesticides are toxic chemicals which are dangerous if contained in the ingested food (Ademoroti 1996, cited in Ize-Iyamu et al 2007).
An analytical research study was conducted at Ogba, Ikoro & Ovia rivers in Edo State concluded that certain degrees of pollution of fish and water are recorded in the samples taken. Human health is endangered by rapid rising of contamination thus; the
report recommends serious monitoring and control of the water species while the three rivers are major supply of the seafood in the state (Ize-Iyamu et al 2007).
[As pesticides can be part of the food chain and then will be transferred from water and fish to carnivores. Consequently], pesticides have much effect on human health like destroying the nerve system, liver’s rotting, chronic diseases, etc (Jeantheau 2009).
Mercury: the watery silver chemical element can excess water through the atmosphere from electrical manufactured goods and other industrial processes. Mercury as a toxic substance has risky effects on offspring such as neurological troubles on fetus including slower reactions, incomplete mental development, brain damage and autism. Similarly, in grown-up people there will be heart illness, Alzheimer’s disease, fatigue and probable mortality. In addition to that, animals are exposed to slower growth, population shrinkage and irregular attitudes (Jeantheau 2009).
Mercury has been recorded in fish in some places of Nigeria especially in Lagos Lagoon, Niger delta and Oyewo were the measured values of mercury were very high. In fact, the approximate discharged mercury quantity into the environment in Lagos metropolis is being estimated per each industrial effluent (Odunlami n.d).
Effects of Water Pollution
Water related Diseases:-On an average 250 million people worldwide succumb to diseases related to water pollution.
Pathogens are responsible for causing following diseases:
Waterborne diseases: including cholera, typhoid, and dysentery etc. are caused by drinking water containing infectious viruses or bacteria, which often come from human or animal waste.
Water-washed diseases: such as trachoma and scabies, are caused by lack of clean water
Water-based diseases: such as schistosomiasis, dracunculiasis etc. spread by organisms that develop in water and then become human parasites.
Water-related: insect vectors, such as mosquitoes, black fly breed in or near water and spread diseases, including dengue, malaria, filariasis etc (Paguntaka 2008).
Besides pathogens contaminated water also contains toxic heavy metals:
Mercury: It may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes. It is a threat to the development of the child in utero and early in life. A significant example of mercury exposure affecting public health occurred in Minamata, Japan, between 1932 and 1968, where a factory producing acetic acid discharged waste liquid into Minamata Bay. The discharge included high concentrations of methyl mercury. The bay was rich in fish and shellfish, providing the main livelihood for local residents and fishermen from other areas. For many years, no one realised that the fish were contaminated with mercury, and that it was causing a strange disease in the local community and in other districts. At least 50 000 people were affected to some extent and more than 2000 cases of Minamata disease were certified. Minamata disease peaked in the 1950s, with severe cases suffering brain damage, paralysis, incoherent speech and delirium (Owa, 2014).
Cadmium: It causes nausea, vomiting, diarrhea, muscle cramps, salivation, sensory disturbances, liver injury, convulsions, shock and renal failure. Itai-itai disease was the name given to the mass cadmium poisoning of Toyama Prefecture, Japan, starting around 1912. The cadmium was released into rivers by mining companies in the mountains. The cadmium and other heavy metals accumulated at the bottom of the river and in the water of the river. This water was then used to irrigate the rice fields. The rice absorbed heavy metals, especially the cadmium. The cadmium accumulated in the people eating contaminated rice. Cadmium poisoning causes weak and brittle bones, pain in spine and legs, coughing, anemia and kidney failure (Owa, 2014).
Nitrate: Nitrate fertilizers used on soil enter our water bodies. It not only makes water unfit for drinking but also causes diseases. In human body, the nitrates are converted to nitrites by microbial flora of intestine. These nitrites then combine with the hemoglobin of blood to form methaemoglobin, which interferes with the O2 carrying capacity of the blood. The disease produced is called methaemoglobinaemia or Blue Baby Syndrome. Symptoms include shortness of breath and blue coloration of skin. Nitrate poisoning is frequent in Rajasthan due to hard and saline water. Several children have died due to this problem (Owa, 2014).
Fluoride: Ingestion of excess fluoride, most commonly in drinking-water, can cause fluorosis which affects the teeth and bones. Chronic high-level exposure to fluoride can lead to skeletal fluorosis, include stiffness and pain in the joints. Acute high-level exposure to fluoride causes abdominal pain, excessive saliva, nausea and vomiting. Seizures and muscle spasms may also occur. Many people in Rajasthan have humped back due to high fluoride content in water sources (Owa, 2014).
Arsenic: The immediate symptoms of acute arsenic poisoning include vomiting, abdominal pain and diarrhoea. These are followed by numbness and tingling of the extremities, muscle cramping and death, in extreme cases. Long-term exposure to high levels of inorganic arsenic include pigmentation changes, skin lesions, hard patches on the palms and soles of the feet (hyperkeratosis), skin cancer, cancers of the bladder and lungs. In China (Province of Taiwan), arsenic exposure has been linked to “Blackfoot disease”, which is a severe disease of blood vessels leading to gangrene.
Lead: Lead poisoning leads to nausea, vomiting, anemia, damages nervous system and kidneys.
Concept of Industrial Water Pollution
Industrial Wastewater
Water is an important requirement in many industrial processes, such as, heating, cooling, production, cleaning and rinsing. Overall, some 5–20 per cent of total water usage goes to industry (WWAP, 2009), and industry generates a substantial proportion of total wastewater. If unregulated, industrial wastewater has the potential to be a highly toxic source of pollution. The vast array of complex organic compounds and heavy metals used in modern industrial processes, if released into the environment can cause both human health and environmental disasters. Industry has a corporate responsibility to take action to ensure discharged water is of an acceptable standard, and accept costs of any required clean up. The most cost- effective solutions usually focus on preventing contaminants from ever entering the wastewater stream or developing a closed system of water use (Corcoran et al. 2010).
Different industries use different amounts of water depending on the size of an industry and the nature and type of production, thus, generation of wastewater from industries tend to vary from one section to another. Industrial wastewater from different processing activities, usually contain a number of elements which when not well handled can threaten the quality of the endpoint of such generated wastewater. The study by Alturkmani (2006) showed that wastewaters may contain suspended, colloidal and dissolved (mineral and organic) solids. In addition, they may be either excessively acidic or alkaline and may contain high or low concentrations of colored matter. These wastes may contain inert, organic or toxic materials and possibly pathogenic bacteria.
Furthermore, Alturkmani (2006) reported that several industries discharge heavy metals, but chromium is the most widely used and discharged to the environment from different sources. Many of the pollutants entering aquatic ecosystems such as mercury, lead, pesticides, and band herbicides are very toxic to living organisms. Also, Belay (2010) observed that industrial wastes are generated from different processes and the amount and toxicity of waste released varies with its own specific industrial processes. Tannery effluents are ranked as the highest pollutants among all industrial wastes. They are especially large contributors of chromium pollution. Belay (2010) explained that in India alone about 2000–3000 tons of chromium escapes into the environment annually from tannery industries, with chromium concentrations ranging between 2000 and 5000 mg/l in the aqueous effluent compared to the recommended permissible discharge limits of 2 mg/l.
Wastewater derived from food production has attributes that are very distinct from other industrial activities. In particular, food processing wastewater can be characterized as friendly in that it generally does not contain conventional toxic chemicals such as those listed under EPA's Toxic Release Inventory with a few exceptions, such as phenolics from the processing of some plant materials. However, food processing wastewaters can be subject to bacterial contamination, which represents a special issue for wastewater reuse. More generally, food processing wastewaters are distinguished by their generally high Biological Oxygen Demand (BOD) concentrations, high levels of dissolved and/or suspended solids [including fats, oils, and grease (FOG)], nutrients such as ammonia and minerals e.g., salts.
Common contaminants of Industrial Wastewater and their Effects
Heavy Metals (Lead, Cadmium, Zinc and Chromium)
Heavy metals as soluble ions are common contaminants of industrial wastewaters. Because of their toxicity they are typically removed prior to wastewater discharge. Heavy metals are naturally occurring elements, which under normal conditions are present at low concentrations in water. Weathering of rocks, soils and volcanic eruptions are among the natural sources of heavy metals in the environment. However, nowadays the anthropogenic contributions of heavy metal pollution to water, air and soil far surpass the natural sources. The main anthropogenic sources of heavy metal pollution include: mining, metal smelting, metallurgical industries and other metal-using industries, waste disposal, corrosion of metals in use, agriculture and forestry, fossil fuel combustion and sports and leisure activities (Mkumbo, 2012).
Zinc (Zn):
Zinc is a transition metal with the following characteristics: period 4, group IIB, atomic number 30, atomic mass 65.4, density 7.14 g cm−3, melting point 419.5oC, and boiling point 906oC. Zinc occurs naturally in soil (about 70mg kg−1 in crustal rocks) but Zn concentrations are rising unnaturally, due to anthropogenic additions. Most Zn is added during industrial activities, such as mining, coal, and waste combustion and steel processing. Many foodstuffs contain certain concentrations of Zn (Davies et al. 1988).
Zinc is one of the most common elements in the Earth's crust. It is found in the air, soil, and water and is present in all foods. In its pure elemental (or metallic) form, Zinc is a bluish-white, shiny metal. Powdered Zinc is explosive and may burst into flames if stored in damp places. Common use for Zinc is to coat steel and iron as well as other metals to prevent rust and corrosion, which is called galvanization. Metallic Zinc is also mixed with other metals to form alloys such as brass and bronze. A Zinc and copper alloy is used to make pennies in the United States. Metallic Zinc is also used to make dry cell batteries (ATSDR, 2005). Elemental Zinc is a lustrous, blue-white to grey metal that is virtually insoluble in water (ATSDR, 1995).
Zinc enters the air, water, and soil as a result of both natural processes and human activities. Most Zinc enters the environment as the result of mining, purification of Zinc, Lead, and Cadmium ores, steel production, coal burning, and burning of wastes. These activities can increase Zinc levels in the atmosphere. Waste streams from Zinc and other metal manufacturing and Zinc chemical industries, domestic waste water, and run-off from soil containing Zinc can discharge Zinc into waterways. The level of Zinc in soil increases mainly from disposal of Zinc wastes from metal manufacturing industries and coal ash from electric utilities. Sludge and fertilizer also contribute to increased levels of Zinc in the soil (ATSDR, 2005).
Major sources of Zinc (Zn): The primary anthropogenic sources of Zinc in the environment are from metal smelters and mining activities (ATSDR, 1995). The production and use of Zinc in brass, bronze, die castings metal, alloys, rubbers, and paints may also lead to its release to the environment through various waste streams. Pure Zinc is usually produced by an electrolytic process in which Zinc oxide is leached from the roasted or calcined ore with sulfuric acid to form Zinc sulfate solution which is electrolyzed in cells to deposit Zinc on cathodes. The primary application of Zinc in metallurgy is its use as a corrosion protector for iron and other metals (Lewis, 1997). In industries, Zinc is mainly found in paints, galvanization, batteries, smelting, fertilizers and pesticides, fossil fuel combustion, pigment, polymer stabilizers. Wastewater which comes from these industries is mainly polluted with zinc, since it is used in large quantities. One of the consequences is that rivers are depositing zinc-polluted sludge on their banks (WCE, 2012)
Lead (Pb):
Lead is one of the heavy metals found in group IV period 6 of the periodic table. Having atomic number 24, atomic mass 52, density 11343Kg/m3, melting point 327.46oC, boiling point 1749oC and its state at room temperature is Solid state. Lead is naturally present in all soils at low levels and not as a single element but in a combined form such as Pb (NO3)2, PbSO4, PbS, and PbCO3 when combined with Oxygen. The U.S Environmental Protection Agency established new standards for Lead in soils in 2001. The standards consider Lead to be a hazard to human health if there are greater than 400 ppm of Lead in bare soil in children’s play areas or 1200 ppm average lead for bare soil in the rest of the yard. For the case of industries, lead is usually found in lead piping in the water distribution system and can be found in paints (as oxides, carbonates), solder, pool cue chalk (as Carbonate, furthermore, lead is the main ingredient in industries dealing with batteries making.
Generally, Lead is generated from various sources include Smelting, Battery Manufacture, Metal recovery, Crystal glass production, Pigment Manufacture, Ceramic and Paints industries. Organic compounds used in petroleum refining. With these sources of Lead in Environment, effects that are associated with presence and accumulation of this heavy metal are such as Fatigue, Insomnia, Headache, Loss of appetite, Constipation, with increased exposure, Blue coloration of gum margins, abdominal cramps, weakening of muscles due to disturbance of peripheral nervous system (Rowland and Cooper, 1983).
Chromium:
Chromium (Cr) is an environmental pollutant element and ranks seventh in abundance in the earth crust. The major contributors of Cr contamination are the leather tanning, electroplating, and stainless-steel industries (Dheri et al., 2007). Many investigations were conducted on phytoremediation of chromium contaminated soils (Mangkoedihardjo et al. 2008). Dheri et al. (2007), investigated comparative phytoremediation of chromium-contaminated soils by fenugreek, spinach, and raya. These results showed fenugreek, spinach, and raya are affective for phytoremediation of chromium contaminated soil. It is well known that chromium is toxic to human, animals and environment (soil, water, and plants) hence prior to its release, it needs high treatment in order to reduce or avoid such impacts. Hence chromium disposal needs to be well monitored so as to avoid its impacts to both human and environmental at large. To prevent the public health and environmental impact of tannery waste in general and chromium in particular the environmental regulation like effluent discharge limit has to be stringent (Belay, 2010).
Cadmium:
Cadmium is a toxic metal occurring naturally in the environment and is considered as a pollutant emanating from industrial and agricultural sources. Exposure of human population to cadmium from air, food and water may produce effects in organs such as kidney, liver, lung, and cardiovascular, immune and reproductive systems (Flowler, 2009). Cadmium is efficiently retained in the kidney (half-time of 10–30 years) and the concentration is proportional to that in urine (Thompson, 2008). Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure level than previously anticipated (Jarup, 2009). Exposure to Cadmium can cause a number of harmful health effects. Eating food or drinking water with high levels of Cadmium can severely irritate or bother your stomach and cause vomiting and diarrhea. Breathing high doses of cadmium can irritate and damage the lungs and can cause death (ATSDR, 1989).
Bai (2009) reported that Cadmium is a toxic heavy metal present in wastewaters from a variety of industries. Therefore, it is necessary to remove it before discharge into the environment. Different methods can be used for removing metals, including filtration, chemical precipitation, coagulation, solvent extraction, electrolysis, ion exchange, membrane process and adsorption.
The Impact of Industrial Water Pollution to the Surrounding Community
Olajumoke & Oluwagbemiga (2017) postulated that, industrial effluents are basically hazardous and as the name implies pose potential risk to human health and the environment if not properly addressed. Those who own, operate, or help manage industrial facility that deals with wastewater, it’s important to understand how wastewater treatment can play a significant role in the overall health of the industry, environment and the living creatures. This is an important part of the process to consider, as ignoring it could earn the industry various fines or lawsuits and pose a potential threat to public health (SAMCO, 2016). The goal of wastewater management is to protect and maintain healthy rivers and oceans for the betterment of the surrounding community. Wastewater must be treated prior to discharge to receiving body whether it’s to the ocean, river or lake so as to manage water appropriately so that it doesn’t causes harm to the environment and living organisms at large by threatening public health, fisheries, wildlife habitat, recreation opportunities and ultimately, our quality of life (Sackey, 2001). In detail this focus on eliminating and/or reducing the harmful effects that may be caused by wastewater so as to attain the balance in water quality between the receiving bodies and the discharged water.
In both developed and developing countries the industrial activities have caused huge amount of untreated wastewater to carelessly release into freshwater streams. In Gulf regions, 80% of industrial effluents were directly discharged into rivers through various media (Islam et al., 2012). Similar observations were made in Nigeria and other developing countries. As there is an increase in industrial activities, the pollution stress was developed on the water bodies and resultant environmental and health problems rose in great extent. In many African states, there is a rapid increase in population, urbanization and industrialization which has altered aquatic diversity due to discharge of pollutant to water bodies (Rahib et al. 2013).
In the Western African region, it is estimated that only 10% of the existing industries treat their wastewaters to any degree. Most of the agro-processing industries discharge their industrial effluent without any form of treatment directly into immediate water bodies and open land. This discharge is affecting the health of the downstream communities not mentioning the threat to aquatic life in the region.
The uncontrolled disposal to the environment of municipal, industrial and agricultural liquid, solid, and gaseous wastes constitutes one of the most serious threats to the sustainability of human civilization by contaminating the water, land, and air and by contributing to global warming. With increasing population and economic growth, treatment and safe disposal of wastewater is essential to preserve public health and reduce intolerable levels of environmental degradation. In addition, adequate wastewater management is also required for preventing contamination of water bodies for the purpose of preserving the sources of clean water (Olajumoke and Oluwagbemiga, 2017).
Industrial Wastewater Treatment Technologies
This method is the most often used in the treatment of wastewater worldwide. In Nigeria in particular this technology is also in use. They may be designed to be anaerobic, aerobic or facultative. Stabilization ponds provide secondary biological treatment and are the most commonly used wastewater pond. Stabilization ponds are normally preceded by some form of primary treatment such as a primary clarifier to reduce the solids entering the pond. Normally, the required multiple ponds in series should have a detention times of 30 days plus. Average depths are three to five feet deep. All ponds must be constructed with impervious material such as clay or an artificial liner to prevent contamination of groundwater and surface water sources in the area.
Constructed Wetland
Constructed Wetlands (CW) is another option for wastewater treatment and it is used worldwide. This technology has helped to reduce the load that natural wetlands were carrying however they are still in use to treat wastewater though currently, CW is becoming more popular and effective for wastewater treatment.
Constructed wetland treatment systems are engineered systems that have been designed and constructed to utilize the natural process involving wetland vegetation, soil and their associated microbial assemblages to assist in treating wastewater. They are designed to imitate the same processes that occur in natural wetlands (Mayo et al. 2011).
Constructed wetlands can be built with a much greater degree of control, thus allowing the establishment of experimental treatment facilities with a well-defined composition of substrate, type of vegetation and flow pattern. In addition, constructed wetlands offer several additional advantages compared to natural wetlands, including site selection, flexibility in sizing and most importantly, control over the hydraulic pathways and retention time. The pollution in such systems is removed through a combination of physical, chemical and biological processes including sedimentation, precipitation, adsorption by soil particles, assimilation by plant tissue, and microbial transformation (Mayo et al. 2011).
Fly ash and Cement Fixation
Fly ash and cement fixation is another process that helps in the reduction of heavy metals from industrial wastewater. A study by Weng and Huang (1994) has shown its effectiveness. Results show that the fly ash can be an effective metal adsorbent, at least for Zn (II) and Cd (II) in dilute industrial wastewaters. Fly ash adsorption capacities for Zn (II) and Cd (II) were 0.27 mg/g and 0.05 mg/g, respectively. A mortar specimen prepared with 10% metal‐laden fly ash showed a 56‐day strength, about the same or even greater than that of cement alone. Leachates from the fixed metal‐laden fly ash, obtained by using both the ASTM and U.S. Environmental Protection Agency‐extraction procedure (USEPA‐EP) leaching tests, exhibit meta concentrations lower than the drinking water standards. Compressive strength and leaching test results suggest that metal‐laden fly ash can be considered for use in secondary construction materials.
Challenges of Industrial Water Management
Water pollution due to industrial discharges is becoming a serious restrictive factor for sustainable development of any society. On weak economies of numerous transitions or other developing countries, water quality management is one of the heaviest burdens. Lack of basic data in planning and designing of wastewater systems and treatment mechanisms is a major challenge facing industrial wastewater management. Usually the main source data for planning are unrealistic and are based on theoretical calculations. Measured parameters of quantity and quality of wastewater are used in very few situations. Lack of practical experience is another challenge, visible in beginner mistakes with wastewater flow, pumping, inlet and outlet hydraulics, detention time, aeration and sludge treatment. Lack of knowledge is reflected in frequent copying of foreign solutions and old projects, without taking in account local situations and other important influences may hinder industrial wastewater management. Poor environmental policies and support from the environmental regulators and consultants may also affect the management of wastewater from industries (McIntosh & Pontius, 2017).
Conception of sewer system Construction of the sewers in the past was mainly purposed for as faster as possible drainage of all present waters to the nearest recipient. With necessity of treating wastewaters this approach is completely changed. Low quality of sewer system is another challenge. The quality of the constructed sewers is very different from place to place, and also dependent as the time when it was constructed. Frequently the channels are not water-tight, and drainage of underground or storm water is a common problem. Poor maintenance of sewer system due to inferior economic situation in most of the industries is another big challenge to most of the industries (EPA, 2018).
2.2 THEORETICAL FRAMEWORK
The Deterministic Theory of Cause-Effect Relationships
The deterministic theory of cause-effect relationships states that knowing the cause – effect relationship is essential in decision making. Through this theory, people are able to quantify a specific water quality problem and thereby support rational management decisions. This can be done at different levels of complexity such as; first, loadings, these are preliminary decisions that can be taken with respect to reduction of loadings from a ranking of the size of actual pollution loadings to a particular receiving water body. The rationale is to assess where the greatest reduction in pollution can be obtained in relation to the costs involved (Mutamim, et al, 2012).
Second, mass balances whereby mass balances can be established using load estimates from pollution sources in combination with the water flow or residence time in the water body. The significance of the different loadings can be evaluated by comparing their magnitude to their contribution to the resulting concentration of the pollutant in the receiving waters. The significance of the different loadings for the pollution level of the receiving water body provides the rational basis for decisions on effective reduction of the pollution level in those waters. (Mutamim, et al, 2012). This theory was relevant to the study since it helped the researcher to understand how industrial waste water affects water sources thus causing pollution. Therefore, through this theory, the researcher achieved the main objective of the study.
2.3 EMPIRICAL REVIEW
In a study carried out by Ocheri (2018) on “Industrial Water Pollution in Nigeria; Types and Health Consequences”, the study found out that water is safe when it is in the order of what nature wants it to be. However, pollution occurs when substances harmful to living things are introduced to water. These substances that make water impure are known as pollutants and are of different compositions. Pollutants may be solids, liquids, gases or mixtures of them and they either cause nuisance or have a direct impact on the health of living things - man, animal, and plant. The paper further discussed the different types of pollution in Nigeria, the health impacts arising from pollution globally and recommends policy measures to reduce the health impact of pollution. It was therefore recommended that the government should monitor the implementation of laws and regulation against pollution and there should be adequate public awareness of environmental issues such as over use of petrol vehicles, over the use of coal, oil and ground water.
Furthermore in a similar study conducted by Ityavyar & Thomas (2019), the study examined the issue of pollution and its attendant consequences on the Nigerian society. In doing so, the paper on the basis of personal observation and secondary sources examined the effects of pollution in Nigeria. The findings showed that environmental problems in Nigeria generally are many, diverse in nature, and are caused by man’s interaction with nature (environment) for exploits in a number of ways-both in the cities; where industrial activities predominate, and rural areas; where agriculture thrives. The paper posited that man utilizes air for survival, harnesses land and water resources for domestic, commercial, industrial, agricultural and other purposes. Through these activities; man directly and/or indirectly create problems which are detrimental to his health/survival, well being, natural existence and stability. The paper also observed that these problems are a consequence of environmental pollution which also degenerates into environmental degradation and several other hazards such as widespread epidemics, depletion of natural habitats, and thus; impede the socio-economic development of Nigeria as a nation. The paper recommended awareness creation and change in attitudes for effective environmental and resources management strategies as a way forward.