1.1 Background of study
Water is one of the earth’s most important resources that use for human life and its quality totally depend on geological environment, recovery, utilization as per need and human activities like domestic, industrial or commercial, mining operations, agricultural etc-(Wagh et al, 2014). Water occupies about 71% of the earth’s surface and yet it is one of the scarcest commodities especially in the developing countries of the world (Karikari and Ansa, 2006). Water is also one of the most demanded of all urban and rural amenities and it is indispensable for man’s activities. Oketola et al,(2010) noted that water is abundant on the planet Earth as a whole, but fresh potable water is not always available at the right time or the right place for human or ecosystem use and water is undoubtedly the most precious natural resource vital to life. Furthermore, water is distributed in nature as surface and ground water in different forms and sources which are oceans, seas, rivers, streams, lakes, ponds, wells, boreholes and springs.
The world is faced with problems related to the management of wastewater. This is due to extensive industrialization, increasing population density and high urbanized societies (McCasland et al., 2008). The effluents generated from domestic and industrial activities constitute the major sources of the natural water pollution load. This is a great burden in terms of wastewater management and can consequently lead to a point-source pollution problem, which not only increases treatment cost considerably, but also introduces a wide range of chemical pollutants and microbial contaminants to water sources (Amir et al. 2004).
In most urban-rural communities in the developing countries especially the Sub-Saharan Africa, surface waters (rivers, streams, and lakes) have been the most available sources of water used for domestic purposes (Higler, 2012). The water from these sources is contaminated with domestic, agricultural, and industrial wastes and is likely to cause water related diseases (Ojekunle, 2012; Ayeni, 2014). Water is a resource that has many uses, including recreation, transportation, hydroelectric power and domestic, industrial and commercial uses (Kumar, 2007). Water also supports all forms of life and affects our health, lifestyle, and economic well- being. Although more than three quarters of the Earth’s surface is made up of water, only 2.8 percent of the Earth’s water is available for human consumption (Iskandar, 2010). At present, approximately one-third of the world’s people live in countries with moderate to high water stress and the worldwide freshwater consumption increases six fold between the years 1900 and 1995 more than twice the rate of population growth, thus, many parts of the world are facing water scarcity problem due to limitation of water resources coinciding with growing population (United Nations Environmental Programme, UNEP, 2002). Nowadays, the main sources of environment pollution are heavy metals and oil extraction and refining, mobile sources, district heating plants, domestic heating, cement production, and irregular garbage burning (Ejupi et al, 2016).
The prevention of pollution of water sources and protection of public health by safeguarding water supplies against the spread of diseases, are the two fundamental reasons for treating waste water. This is accomplished by removing substances that have a high demand for oxygen from the system through the metabolic reactions of microorganisms, the separation and settling of solids to create an acceptable quality of wastewater effluents, and the collection and recycling of microorganisms back into the system, or removal of excess microorganisms from the system (Abraham et al 1997). The major microorganisms found in wastewater effluents are viruses, bacteria, fungi, protozoa and helminthes. Although various microorganisms in water are considered to be critical factors in contributing to numerous waterborne outbreaks, they play many beneficial roles in wastewater effluents (Kris, 2007).
Rivers provide a variety of services for human populations, including water for drinking and irrigation, recreational opportunities, and habitat for economically important fisheries (Leroy, 2002). The growing problem of pollution of river ecosystem has necessitated the monitoring of water quality (Ravindra, 2003). Fresh water is a finite resource, essential for agriculture, industry and even human existence, without fresh water of adequate quantity and quality, sustainable development will not be possible (Kumar, 2007). Rivers play a major role in assimilation or carrying off of municipal and industrial wastewater and runoff from agricultural land, the former constitutes of constant polluting non- point sources whereas the later is a seasonal phenomenon (Muduli and Panda, 2010). With the rapid development in agriculture, mining, urbanization, and industrialization activities, the river water contamination with hazardous wastes and wastewater is becoming a common phenomenon (Ali, 2012).
The Great Kwa River is one of major tributaries of the Cross River estuary and according to Wilson (2002), estuaries and the most productive ecological systems around the world. As reported by Akpan (2000), this important river takes it rise from Oban Hill in Nigeria, flows southwards and discharge into the Cross River estuary along longitude 445N and longitude 820E. The lower reaches of the river drains the eastern coast of the Calabar municipality, the capital of Cross River State. Waste water generated from hospitals usually contain pathogens human tissues and fluids partially metabolized pharmaceutical substances with genotoxic properties, chemical substances, heavy metals, and radioactive waste, which may endanger public health and welfare. Waste water from the Teaching Hospital drains via a reservoir directly into the Great Kwa River. Despite the potential dangers of the wastewater discharge from the University Teaching Hospital into the Great Kwa River and the importance of the River itself on the socio-economic life of the people of the area. Constant use of heavily polluted water for a long time usually results in health problems.
Furthermore, as human population increases, more pressure is put on available water resources in meeting human water needs and for waste disposal. Adeyemi et al, (2009) stated that people residing close to rivers are predominantly farmers and occasional dredgers (sand miners). They use poultry droppings as well as chemical fertilizers to enrich their farmlands; these constitute pollutants which drain into the river through run-offs. Furthermore, they were of the opinion that most Rivers in Nigeria had in recent times come under stress as a result of rapid urbanization. All the domestic and industrial wastes as well as sewage from all parts of Port Harcourt are washed into the river during run-off (Olorode et al, 2015).
However, with increasing population pressure associated with the export free zone status of Calabar, human settlement and industrial layout are expanding rapidly into the freshwater mangrove swamp of the Great Kwa river, and due to human activities and lack of sewage treatment facilities in Calabar municipality, the rivers ecosystem is under threat by human activities and industrial waste, thus contaminating the water.
The need for good water quality has been of growing concern in Nigeria and worldwide as anthropogenic activities are fast degrading most water bodies, these activities which are agricultural practices, human domestic activities and dredging, all result in pollution of the natural habitats of aquatic organisms. Rivers serve as sinks to most wastes that result from these anthropogenic activities (Onyegeme and Ogunka, 2015). The impact of municipal waste discharge and re-suspension on the water quality in great kwa river proceeds from human activities (both from natural and artificial engagements). The environment waste discharge has tremendous impact on living aquatic organism, which may lead to various abnormalities and their growth deficiency.