AN ASSESSMENT OF THE IMPACT OF UNTREATED SEWAGE DISPOSAL ON FARMLANDS

CHAPTER ONE

INTRODUCTION

Background of the Study

Sewage refers to the untreated discharge of industrial effluents and domestic wastewater. The growing population and industrialisation have resulted in greater strain on land resources and water, perhaps leading to a higher volume of sewage discharge. Sewage disposal refers to the method of managing and eliminating wastewater from residential and commercial establishments. This wastewater, often consisting of a liquid containing minute solid particles, is transported through enormous pipes known as sewers. Wastewater sustains the livelihoods of impoverished farmers, but it also alters the environmental conditions. In regions where safe effluents are not accessible, sewage is utilised for irrigation of crops and vegetables (Ensink et al., 2018). Urban treated wastewater, which is considered an alternative water source for irrigation in arid areas with high competition for water, has been utilised due to its satisfactory quality (Zhang and Shen, 2019; Khalid et al., 2018). Researchers have long been interested in studying the effects of short- and long-term wastewater irrigation on soil physicochemical qualities, plant production, pollution levels, and surface and groundwater resources. The use of urban treated wastewater has significant implications in these areas.Using treated wastewater in farmland is considered a viable strategy for both wastewater disposal and sustainable agriculture in areas with limited freshwater resources (Duan et al., 2020). The efficacy of this water resource in arid and semi-arid regions has been demonstrated by the impact of treated wastewater on plant growth, since its nutrients can improve agricultural yields while avoiding the need for excessive chemical fertilisers (Zhang and Shen, 2019). Wastewater contains three crucial macronutrients: nitrogen, phosphorus, and potassium, along with various micronutrients necessary for plant growth. Jiménez et al. (2021) and Murtaza et al. (2020) have found that this approach can significantly diminish the reliance on chemical fertilisers in agricultural areas. Nevertheless, the impact on human health, crop production, and soil physicochemical features may vary depending on the quality of the wastewater. Some of the consequences include diseases caused by microbial contamination, higher soil salinity and sodium absorption ratio, alterations in soil hydraulic conductivity, buildup of nutrients, and plant toxicity (Shoushtarian and Negahban Azar, 2020; Muyen et al., 2021; Andrews et al., 2018). Sewage water is utilised in places that only rely on a sewerage system for irrigation, covering an estimated area of approximately 32,500 hectares (Ensink et al., 2018). However, there is no specific information available regarding which crops are irrigated using sewage water. Due to the high cost of vegetables in the market, impoverished farmers place importance on sewage water as it contains nutrients and provides a reliable source. Ensink et al. (2018) conducted the study. There are certain landlords that treat sewage water and provide it to farmers for a fee. The use of sewage water increases agricultural intensity, resulting in a lower usage of canal water (US$ 43 ha−1) compared to sewage water (US$ 173 ha-1). Therefore, sewage water is considered a win-win situation for all individuals involved. The combination of a large population, inadequate water distribution, drought, and salt exacerbates the scarcity of canal water, perhaps necessitating further reliance on sewage water. Sewage varies in composition across different locations, but typically contains both organic and inorganic molecules, as well as heavy metals (Hussain et al., 2022).Furthermore, the impact of sewage water irrigation on soil and crop growth duration beyond the first stage of seedling development has received less attention thus far.Therefore, a survey will be conducted in order to assess the impact of untreated sewage disposal on farm lands.

Statement of the Problem

The global disposal of untreated sewage has emerged as a major environmental concern, carrying considerable implications for the utilisation of agricultural land. Sewage, which consists of human waste, industrial effluents, and other domestic byproducts, frequently contains elevated concentrations of pathogens, heavy metals, and organic contaminants. Direct discharge of untreated sewage onto farmlands can have adverse impacts on soil health, crop yield, and the overall ecological equilibrium. In addition, when sewage is not treated, it can change the physical and chemical characteristics of the soil, including its pH, salinity, and structure, which in turn impacts its ability to support plant growth and fertility (He et al., 2020). Applying sewage with a high organic content can initially enhance soil fertility by supplying vital nutrients such as nitrogen and phosphorus. Nevertheless, the gradual buildup of organic matter and minerals can result in imbalances in soil nutrients, heightened salinity, and the exhaustion of vital micronutrients, ultimately causing harm to crop output (Kirkham, 2018). Utilising untreated sewage on agricultural fields also presents substantial hazards to public health. Plants cultivated in polluted soils have the potential to accumulate heavy metals and other harmful compounds, which can subsequently poison the food chain. Consuming contaminated food products can result in a range of health problems, including gastrointestinal infections, heavy metal toxicity, and chronic diseases including cancer (Singh & Agrawal, 2020). In addition, sewage-borne diseases have the potential to pollute both groundwater and surface water sources, hence increasing the dangers faced by communities who depend on these water supplies for drinking and irrigation (Toze, 2018). 

To avoid these dangers, it is crucial to use effective management measures such as treating sewage before applying it to agricultural fields and closely monitoring the quality of soil and crops.Prior research indicates that a high salt absorption ratio in urban treated sewage leads to an increase in sodium exchangeable content in soil, which in turn causes soil degradation, reduced permeability, decreased hydraulic conductivity, and hampers root development. (Paudel et al., 2018; Yalin et al., 2019). Hence, it is in the light of these that the study seeks to assess the impact of untreated sewage disposal on farm lands.

1.3 Objectives of the Study

The main purpose of this study is to assess the impact of untreated sewage disposal on farm lands. Specifically, the study will;

To assess the extent of untreated sewage disposal on farmlands.

Assess the effects of untreated sewage disposal on farmlands.

Investigate the health risks associated with the consumption of crops grown on farmlands exposed to untreated sewage.

Propose strategies for mitigating the negative impacts of untreated sewage disposal on farmlands and promoting safe agricultural practices.

1.4 Research Questions

The following questions have been prepared for the study:

To what extent does untreated sewage disposal impact farmlands?

What are the effects of untreated sewage disposal on farmlands?

What health risks are associated with the consumption of crops grown on farmlands exposed to untreated sewage?

What are the strategies for mitigating the negative impacts of untreated sewage disposal on farmlands and promoting safe agricultural practices?

1.5Research Hypotheses

H0: Untreated sewage disposal has no significant impact on farmlands.

Ha: Untreated sewage disposal has a significant impact on farmlands.

1.6 Significance of the Study

This study will provide valuable insights to farmers and agricultural workers who depend on the fertility and productivity of farmland for cultivating crops, enabling them to make well-informed choices about land utilisation and crop management. Additionally, it will enhance knowledge regarding the potential hazards linked to the utilisation of polluted water or soil, thereby promoting improved methodologies and potentially pushing for more secure waste management regulations.Furthermore, the results of the study will potentially provide guidance for the establishment of waste treatment and disposal regulations, with the goal of mitigating the environmental and health hazards linked to untreated sewage.

 Moreover, subsequent researchers will use it as a literature review. This means that other students who may decide to conduct studies in this area will have the opportunity to use this study as available literature that can be subjected to critical review.

1.7 Scope of the study

The scope of this study is boarded on the impact of untreated sewage disposal on farm lands. Empirically, the study will evaluate the extent of untreated sewage disposal on farmlands, assess the effects of untreated sewage disposal on farmlands and investigate the health risks associated with the consumption of crops grown on farmlands exposed to untreated sewage.

Geographically, the study will be delimited to residents of Cameroon.

1.8 Limitation of the study

In the course of carrying out this study, the researcher experienced some constraints, which included time constraints, financial constraints, language barriers, and the attitude of the respondents.In addition, there was the element of researcher bias. Here, the researcher possessed some biases that may have been reflected in the way the data was collected, the type of people interviewed or sampled, and how the data gathered was interpreted thereafter. The potential for all this to influence the findings and conclusions could not be downplayed. More so, the findings of this study are limited to the sample population in the study area, hence they may not be suitable for use in comparison to other schools, local governments, states, and other countries in the world.

1.9 Definition of Terms

Sewage: Wastewater that is generated from domestic, industrial, and commercial activities, which typically contains human waste (faeces and urine), household waste (such as detergents and food residues), and water used for washing, bathing, and cleaning.

Sewage disposal: The process of collecting, treating, and safely discharging or recycling sewage to prevent pollution and protect public health.

Farmlands: Areas of land designated and used primarily for agricultural activities, including the cultivation of crops, rearing of livestock, and other farming practices.

Untreated sewage: Untreated sewage is waste water that has not undergone any treatment to remove contaminants, pollutants, or harmful substances. It contains raw human waste, chemicals, and other waste materials and can pose serious environmental and health risks if released into the environment.