1.1 BACKGROUND OF STUDY
The availability of good quality water is one of man’s basic daily needs for preventing diseases and improving quality of life. Water remains one of the world’s most abundant natural substances and it is in constant circulation. Natural water contains some types of impurities whose nature and amount vary with source of water. Metals for instance, are introduced into aquatic system through several ways which include, weathering of rocks and leaching of soils, dissolution of aerosol particles from the atmosphere and from several human activities, including mining, processing and the use of metal based materials (Ipinmoroti et al. 1993; Adeyeye, 1994). Metals after entering the water many be taken up by fauna and flora and eventually, accumulated in marine organisms that are consumed by human being (Asaolu et al., 1997).
Water is absolutely essential to life, not only human but all life, plant and animal. It is a dispersion medium for all biochemical reactions which constitutes the living process and takes part in many of these reactions. Without water, life cannot survive.
Therefore, the quality of water poses vital concern for mankind since it is directly linked with our health and welfare. Over 97% of the total water supply is contained in the oceans and other saline bodies of water and is not readily usable for most purposes. Of the remaining 3%, a little over 2% is tied up in ice caps and glaciers (about 12.4%), 0.62% was found in groundwater supplies, the surface water like lakes and rivers cover about 0.019% and finally, the water vapour constitute 0.00%. Well water is believed to be comparatively much clean and free from pollution than surface water. However, indiscriminate discharge of industrial effluents, domestic sewage and solid waste dump causes well water to become polluted and creates health problems (Patil and Patil, 2010). There are various ways in which well water is contaminated, amongst which are; the use of fertilizer in farming (Altman and Parizek, 1995), seepage from effluent bearing water body (Adekunle, 2009). Most of the industries discharge their effluent mostly without proper treatment into nearby open pits or pass them through unlinked channels, resulting in the contamination of well water (Jinwal and Dixit, 2008). Hydro-geochemical conditions are also reported to be responsible for causing variations in water quality (Manhata et al., 2004). Well water has usually higher total dissolved solid (TDS) concentration than the surface water because of mineral pick up from soils and rocks.
Anka is a Local Government Area in Zamfara State, Nigeria. Its headquarters are in the town of Anka at 12°06′30″N 5°56′00″E. It has an area of 2,746 km² and a population of 142,280 at the 2006 census. While Gusua sits just north of a line drawn from Kebbe to Kano, it is the capital of Zamfara State. Gusau is a city and Local Government Area located in northwestern Nigeria, Its population is mostly Hausa with some Fulani, Yoruba, Igbo, Igala etc. The LGA has an area of 3,364 km² and a population of 383,162 (2006 census).
Series of researches have been conducted to examine the level of heavy metals in water bodies. El Bouraie et al. (2010) studied the distribution of heavy metals (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surface river water and the bed sediments of Rosetta Branch and the impacts of heavy metals on the water quality were monitored. The heavy metal concentrations in river water and their contents in the bed sediments were studied three times before, during and after winter period (low flow conditions) from August 2007 to April 2008. The heavy metal concentrations in the river sediments were remarkably high, but varied among sampling points, and the concentrations in water were mainly within the permissible limits. The heavy metal contents in bed sediment were highest during closure of winter period. Guhathakurta and Kaviraj (2000) determined the concentrations of Cd, Pb, Zn and Fe in samples of water, sediment, shrimp and mullet from India’s Sunderban fresh water lake. Okonkwo et al. (2005) conducted a study on three rivers in South Africa and compared heavy metal concentrations in water samples collected during the winter and the summer. Metal concentrations were higher in the winter than in the summer, probably due to increase in water volume in the winter. The Pb concentration was higher than the other metals in each of these three rivers during both seasons
Well water in some area is noted for high concentration of particular ions or elements such as magnesium, boron etc. Well water contains various types of pollutants and several other substances are dissolved in it. These substances may be useful for human body but in a specific limit (Ranjana, 2009). Well water is a preferred source of water because of its high quality with respect to portability and the minimum treatment requirement. For individual homes, they find surface water in remote mountains is as attractive because of their more desirable chemical characteristics and reliability. In general, the importance of well water for existence of human society cannot be overemphasized. Hence, there is always a need for the protection and management of well water quality. With respect to the above mentioned well water quality, this study examine the physico–chemical analysis and selected heavy metal estimation of well water in Anka and Gusua town.
1.2 STATEMENT OF PROBLEM
The vast growth in urbanization has further affected well water quality due to overexploitation of resources and improper waste disposal practices. Large volumes of waste are concentrated and discharged into a relatively small area (Rao and Mamatha, 2004). Lack of access to safe water is strongly correlated with poverty, and the provision of safe drinking water is considered to be a fundamental step in a community’s transition out of poverty (Sachs J, Lenton R, Wright AM, Lewis K (2005). Villages in Anka and Gusua town are characterized by different types of basement complex formations. At present there is no major industry in and around the study area, yet household waste water and garbage are directly discharged into the area. The water supply for human consumption in these areas is often directly sourced from well water without biochemical treatment and the level of pollution has become a cause for major concern. The water used for drinking purposes should be free from toxic elements, living and non-living organisms and excessive amount of minerals that may be harmful to health. Keeping this in focus, the quality aspects of well water in villages around Anka and Gusua town were analyzed for general water quality.
1.3 AIMS /OBJECTIVES OF STUDY
The overall aim of this study is to examine the physico–chemical analysis and selected heavy metal estimation of well water in Anka and Gusua town. An important part of the study is also to contribute to further understanding of the main factors affecting well waters in the study area.
The specific objectives for this study will include:
- To investigate some physical and chemical water quality parameters in well water samples collected from different well water sources in Anka and Gusua town.
- To provides information on the levels of heavy metals and physico-chemical parameters in well water sources in Anka and Gusua.
- To investigate the impacts of selected pollution sources on the quality of water in hand dug well water in Anka and Gusua.
- To determine concentration of selected heavy metals in the well water sample in Anka and Gusua town.
1.4 RESEARCH HYPOTHESIS
HO: the well waters from Anka and Gusua town is not safe for human consumption.
H1: the well waters from Anka and Gusua town is safe for human consumption.
H0: there is low level of acidic causing substances in the soil of the study area.
H1: there is high level of acidic causing substances in the soil of the study area.
1.5 SIGNIFICANCE OF THE STUDY
Concentrations of heavy metals are usually high in well waters from the northern region. Different technologies may be applied to diminish these high levels in well water for human consumption. The study on well water has a great significance in helping alleviate certain problems which can pose risk to human health. This study investigates the physico–chemical analysis and selected heavy metal estimation of well water. The study will help estimate the status of heavy metal present in well water in Ansa and Gusua and suitability of this water source for consumption purpose. Similarly, the study is also important for providing scientific evidences before people using this well water especially for every drinking purpose that help them to take care from being infected by poisonous chemicals and microorganisms from different sources. Thus, at the completion of the study the findings will be relevant to; all the inhabitants from these regions using well water, health workers, beverages companies, NAFDAC and students from science departments as a whole.
1.6 SCOPE OF STUDY
The topic of this nature that has to do with physico–chemical analysis and selected heavy metal estimation of well water is broad in nature, and as such it’s difficult to gather information from relevant source in the state. As a result of this, the researcher limits his research to Anka and Gusua town, both in Zamfara state.
1.7 LIMITATION OF STUDY
The researcher experienced some limitations such as:
AVAILABILITY OF RESEARCH MATERIAL: The research materials available to the researcher at the time of this study were insufficient, thereby limiting the study.
Time: the time at the disposal of the researcher which was allocated for the study was a major limitation as the researcher had to combine other
Finance: The finance at the disposal of the researcher in the course of the study could not permit wider coverage as resources are very limited as the researcher has other academic bills to cover.
1.8 DEFINITION OF TERMS
Heavy metal: Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers.
Analysis: Analysis is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it, or detailed examination of the elements or structure of something.
Well water: Well water is an excavation or structure created in the ground by digging, driving, boring, or drilling to access groundwater in underground aquifers. The well water is drawn by a pump, or using containers, such as buckets, that are raised mechanically or by hand.
Contaminants: A contaminant is any potentially undesirable substance (physical, chemical or biological). It usually refers to the introduction of harmful human-made substances.
Turbidity: Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
Total hardness: Total hardness is a measurement of the mineral content in a water sample that is irreversible by boiling. Therefore, total hardness can be equivalent to the total calcium and magnesium hardness. Total hardness is determined by the multivalent cation’s concentrations present in water.