1.1 Introduction
Irrigation is the artificial process of applying controlled amounts of water to land to assist in production of crops. Utilizing wastewater for irrigation is one option to meet agricultural needs. The main reasons for the use of wastewater are highly saline ground water, spell of droughts that depleted ground water as well as water table and the nutrient value of wastewater, urbanization and nearby urban markets and reliability of wastewater (Ensink et.al. 2004). Irrigation with treated, poorly treated, diluted, and even raw domestic wastewater is a widespread practice in urban and peri-urban areas in most developing countries (Hamilton et al., 2007; Keraita et al., 2008; Scott et al., 2004). Among different sources Industrial and Municipal wastes are major contributors to wastewater supply. Wastewater could be quite useful, if it is applied after proper treatment using science and technology (Bahri, 2008).
This chapter will address the background information that motivated this study, the challenges that prompted it, its aim, and its objectives as a preface to subsequent sections of the study. Additional factors include the study's significance, scope, limitations, research questions and hypotheses, and the definition of technical terms.
1.2 Background of Study
The population of Nigeria is always on the increase, with the World Bank estimating the population of Nigeria to hit over a 300 million in the year 2035, the gap between the supply and demand for water is widening and is reaching such alarming levels that in some parts of the world it is posing a threat to human existence. Since 1950 The world population has doubled while water consumption has increased six-fold. By 2025, it is expected that 3.4 billion people will be living in countries defined as water-scarce. Scientists around the globe are working on new ways of conserving water. It is an opportune time to refocus on one of the ways to recycle water-through the use of wastewater for irrigation and other purposes.
Wastewater supports livelihoods and generates considerable value in urban and peri-urban agriculture despite the health and environmental risks associated with this practice (Scott et al., 2000 and 2001). Water that contains human waste is useful even if it is applied untreated but untreated industrial wastewater is affecting the productivity of agricultural labourer by increasing the probability of sickness (Ensink et al., 2002). Untreated wastewater could be cost effective when the costs of negative externalities are not included in the analysis. After accounting for negative externalities (e.g., impact on human health) it might not be feasible for agriculture use (Ensink et.al. 2004).
On the other hand, wastewater use in crop production is not without some risks. The main risk associated with wastewater irrigation is infection with intestinal helminthes. Also, depending on the source of the wastewater it might contain chemical pollutants and heavy metals that can accumulate in the soil and crops thereby posing a threat to human health. However, a major drive towards wastewater use is the fact that it contains high levels of nutrients, reducing the need for and cost of fertilizers. Consequently, many farmers using wastewater are better able to support themselves and their families and often create extra employment (Spore 2002).
Furthermore, the continuous demand for certain crops especially vegetables has increased the need to cultivate these crops all year round. This in effect leads to the dependence on wastewater during the dry seasons or during periods of drought. Also, due to the light water requirement of some crops, the use of wastewater to augment the freshwater, if any, becomes inevitable. In many areas, the few freshwater supply stations (boreholes) are owned by individuals, and the water is sold to others who cannot afford to set up one. In such a situation, the resource poor farmers are forced to resort to a cheaper alternative - wastewater. However, unregulated use of wastewater poses some risks to human health and the environment. Because of these risks, the prevailing scientific approach to wastewater irrigation advocates treatment before use. But the reality is that many developing countries lack the resources to build and maintain treatment facilities.
A negligible proportion of wastewater is treated and no clear regulation exists for wastewater use in urban agriculture in Pakistan (Ensink et al., 2004). Irrigation of agricultural lands with wastewater increases crop production but also heavy metal concentration and the rate of farmer’s infection increases (Ramirez et al., 2002).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Health Impacts of Waste Water Irrigation of Vegetable.
1.3 Statement of Problems
Investigation revealed that wastewater use in crop production is not without some risks. The main risk associated with wastewater irrigation is infection with intestinal helminthes. Also, depending on the source of the wastewater it might contain chemical pollutants and heavy metals that can accumulate in the soil and crops thereby posing a threat to human health. However, a major drive towards wastewater use is the fact that it contains high levels of nutrients, reducing the need for and cost of fertilizers. Consequently, many farmers using wastewater are better able to support themselves and their families and often create extra employment (Spore 2002).
Furthermore, the continuous demand for certain crops especially vegetables has increased the need to cultivate these crops all year round. This in effect leads to the dependence on wastewater during the dry seasons or during periods of drought. Also, due to the light water requirement of some crops, the use of wastewater to augment the freshwater, if any, becomes inevitable. In many areas, the few freshwater supply stations (boreholes) are owned by individuals, and the water is sold to others who cannot afford to set up one.
In such a situation, the resource poor farmers are forced to resort to a cheaper alternative – wastewater. However, unregulated use of wastewater poses some risks to human health and the environment. Because of these risks, the prevailing scientific approach to wastewater irrigation advocates treatment before use. But the reality is that many developing countries lack the resources to build and maintain treatment facilities.
1.4 Aim and Objectives of Study
The aim of the study is to examine the Health Impacts of Waste Water Irrigation of Vegetable. In achieving this aim, the following specific objectives were laid out as follows:
- To evaluate the health implications of domestic waste water for irrigation of vegetable crops;
- To investigate the quality of irrigation water used by informal vegetable farmers;
- To assess the use of domestic waste water for irrigation of vegetable crops; and
- To ascertain the perceptions of farmers and consumers on irrigation water quality and vegetables produce from the practice.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What are the health implications of domestic waste water for irrigation of vegetable crops?
- What is the use of domestic waste water for irrigation of vegetable crops?
- What is the quality of irrigation water used by informal vegetable farmers?
- What are the perceptions of farmers and consumers on irrigation water quality and vegetables produce from the practice?
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