Water pollution: causes, impacts and current efforts to address the issues of water pollution along river Meizimera-kihihi, Kanugu District,Uganda.

Background

The term pollution refers to adding harmful substances to the level at which they affect the environment. Pollution is the introduction of any substance, such as solid, liquid, or gas, into the environment in an amount that can hurt the environment, wildlife, human health, and well-being. Three major categories of pollution are affected by the type of environment being affected. These factors include water, air, and land pollution. Harmful substances are called pollutants, including nitrogenous wastes, domestic wastes, metal, plastics, and many others. Some pollutants are biodegradable, whereas others are non-biodegradable. Biodegradable substances can be broken down by natural processes, which are made from organic materials from animals, plants, or microorganisms such as food waste, cotton, and paper, while any natural processes cannot break down non-biodegradable substances which are made from synthetic materials such as bottles, glass, plastic bags and aluminum cans (Manasa & Mehta, 2020; Sahoo & Goswami, 2024).

Pollution, a critical global issue, arises when harmful contaminants enter the environment, negatively impacting ecosystems, wildlife, and human health. Water pollution originates from various sources, including agricultural runoff, industrial discharges, and urban waste, introducing key pollutants such as nutrients, heavy metals, and plastics into our rivers, lakes, and oceans (Ajibade et al., 2021; Gavrilescu et al., 2015; Khan et al., 2022). Likewise, air pollution is defined by harmful substances in the atmosphere, which pose significant health risks due to exposure to particulate matter, nitrogen oxides, and volatile organic compounds.

Looking at land pollution, it arises from the activities that are carried out by human which degrade the surface of the Earth’s, with solid waste mismanagement, chemicals from agricultural activities, and hazardous waste from the industries all contribute to degradation of the environment (Fazakas et al., 2024; Manisalidis et al., 2020; Odubo & Kosoe, 2024). Recognizing the many forms of pollutants, both biodegradable and non-biodegradable, is critical to establishing effective mitigation methods. As pollution continues to endanger environmental health and human well-being, immediate action is required through waste reduction, sustainable practices, and strengthened regulatory policies to ensure a cleaner, safer world for future generations (Kolawole & Iyiola, 2023; Qadeer et al., 2022; Tong et al., 2022).

Therefore, this study aims to analyze the causes, impacts, and current efforts to address water pollution in Meizimera-Kihihi, Kanungu District, Uganda. Kihihi is the second largest city in the Kanungu District and is situated in Western Uganda. The district features many rivers and streams, including the Kiruruma, Birara, Nchwera, Ishasha, and Meizimera rivers. The people of Kihihi use the river Meizimera for various purposes such as fishing, irrigation, washing, bathing, drinking, religious and cultural purposes, brick making and sand mining, recreation, and livestock watering. The dependence on rivers for various purposes increases the risks of water pollution, which has many harmful effects on human health, the economy, and the environment. A description of the pollution of the river and its consequences is elaborated below:

Water pollution

Globally, over 80% of wastewater worldwide is discharged into water bodies without adequate treatment (UN report, 2020), and in Asia, only one-third of wastewater is treated before being discharged (Asian Development Bank, 2023). In Africa, the lack of clean water and sanitation is a significant challenge in many countries, affecting approximately 319 million people worldwide. In East Africa, eutrophication and algal blooms of Lake Victoria pose significant environmental and public health risks. In Uganda, studies show that only 30% of the population has access to improved sanitation facilities; hence there is a widespread contamination of water sources with fecal matter and plastic, especially in urban centers (WHO, 2019; UNEP, 2020; Manasa & Mehta, 2020; Sahoo & Goswami, 2024).

Water pollution occurs when harmful substances contaminate fresh and marine water bodies such as groundwater, rivers, lakes, and oceans, rendering them unfavorable for various purposes such as drinking, recreation, and support to aquatic life. Over 80% of human-generated sewage is dumped untreated into rivers and oceans, causing pollution that causes over 50 diseases. In addition, poor water quality is linked to 80% of diseases globally (Lin et al., 2022). According to Taylor et al. (2008) and Sahoo and Goswami (2024), progressive increases in industrialization, urbanization, and agricultural practices are the leading causes of water pollution. This alleviates the most common problem of eutrophication, where inland waters and rivers are polluted with nitrogen and phosphorus runoff from fertilizers and the discharge of sewage and effluents.

Water pollution is still a major problem in the world, with detrimental effects on ecosystems and human health. It is mostly generated by human activities, but it comes from several interrelated sources. Because contemporary farming methods rely on fertilizers and pesticides, agricultural runoff plays a significant role in the release of nutrients, especially nitrogen and phosphorus, into water bodies. These substances have the potential to cause eutrophication, or excessive algal growth, in these bodies of water, which drastically lowers oxygen levels and can result in hypoxic conditions that are detrimental to aquatic life.

This can lead to a loss of biodiversity, disturb regional ecosystems, and have an impact on the food chain (Lan et al., 2024; Vantarakis, 2021). Additionally, one of the main causes of water contamination is the outflow of wastewater from homes. Untreated sewage is frequently dumped straight into rivers and lakes in many towns across the world due to a lack of proper sanitation facilities. This kind of discharge increases the danger of waterborne illnesses like cholera, typhoid fever, and dysentery by introducing different pathogens, such as bacteria, viruses, and protozoa, into water sources (Arnold, 2024). Children, the elderly, and those with compromised immune systems are among the most vulnerable groups impacted by these diseases, and drinking tainted water can have a serious negative influence on their health (Pond, 2005).

Severe water pollution is also caused by industrial processes as companies discharge untreated or insufficiently treated wastewater into adjacent bodies of water. Heavy metals, hazardous compounds, and organic contaminants that can build up in the water and bioaccumulate in aquatic life are frequently present in these discharges. Particularly when tainted fish or water winds up on the dinner plates of unwary consumers, prolonged exposure to such toxins can cause major health concerns, such as neurological abnormalities, developmental disorders, and different types of cancer (Adams, 2016). Furthermore, by introducing toxic and non-biodegradable components into freshwater systems, inappropriate solid waste disposal methods, such as the careless handling of plastics and other hazardous items, deteriorate water quality (Datta et al., 2024).

These contaminants have a wide-ranging and intricate effect on human health. Chronic exposure to heavy metals and organic pollutants can cause long-term health problems, such as metabolic disorders and endocrine changes, in addition to the immediate hazards of waterborne infections (Ojha & Tiwary, 2021). Additionally, the financial constraints of medical expenses and missed production can be substantial in communities that depend on contaminated water sources for cooking, drinking, and sanitation. The health risks are exacerbated by the psychological effects of living in contaminated surroundings, which can result in elevated stress and social instability.

Although efforts have been made to reduce water pollution, this phenomenon remains a challenge in most parts of the world. The dependence on rivers for various purposes increases the risks of water pollution, which has many harmful effects on human health, the economy, and the environment. Therefore, this report aims to explore the causes and impacts of water pollution, assess current efforts to address this problem, and provide recommendations for future action. The economic activity and terrain of the area have an impact on the river Meizimera as observed and recorded below: All Observations were made during the study.

The issues of water pollution affecting the river of Meizimera-kihihi range from the decrease in water clarity as a result of pollutants, which reduces the transparency of water, making it difficult for aquatic plants to photosynthesize. Changes in river flow due to pollution can lead to flooding and erosion. Excess nutrients from the runoff of agricultural activities and sewage lead to eutrophication, causing algal blooms and the depletion of oxygen levels in the river (Devlin & Brodie, 2023). Contaminated water poses many health challenges such as typhoid, cholera, and diarrhea to local communities that depend as a source on the river as a source of water, and there has been a decline in fish populations in the river which affects the livelihoods of fishermen (Isukuru et al., 2024; Baba, 2024).

Figure 1. Shows the environmental background of River Meizimera-Kihihi Kanugu, Uganda.

These are the environmental areas of River Meizimera, Kihihi, Uganda. The appearance of the river changes with the seasons; there is an increase in the flow of water during the rainy season and a decrease during the dry season. The river has been affected by pollution and human activities, which affect water quality and the aesthetic value in some areas of the river (Researcher’s observations, 2024). The hydrology and environmental quality of the River Meizimera in Kihihi, Uganda, are significantly impacted by the considerable seasonal variations that occur there. Increased precipitation, which can reach 100 to 250 millimetres per month, causes a discernible rise in water flow during the rainy season, which usually lasts from March to May and again from October to November (Mileham, 2008).

Increased runoff results from this rainfall spike, especially from nearby urban and agricultural regions (Cristiano et al., 2017). As a result, pollutants, sediments, and nutrient loads are carried away by runoff, which can worsen water quality and have an impact on aquatic ecosystems (Tiwari & Pal, 2022). The dry season, which typically lasts from June to September, on the other hand, delivers lower precipitation levels, occasionally dipping below 50 millimeters per month (Ojara et al., 2024), which reduces water flow. Because of this low flow, pollutants may be concentrated in the river, worsening problems with water quality and reducing the river’s aesthetic appeal in some areas. Furthermore, during the rainy season, human activities like urbanization and agriculture close to the riverbanks increase runoff, which causes sedimentation, chemical contamination, and changes to the river’s natural habitat (Chakraborty & Chakraborty, 2021; Mbonaga et al., 2024; Razali et al., 2020).

Figure 2. Shows rice processing factories along River Meizimera, an industrialized area with many rice processing factories, coffee processing factories, and grain milling factories.

In Kihihi, Uganda, the Meizimera River is an essential stream that sustains the local ecology and makes a substantial economic contribution to the area. The river, which flows through a heavily industrialized region with many rice processing factories, coffee processing facilities, and grain milling plants, draws over 1,000 tourists and employees every day. As a result, there is a lot of activity, and some of the waste that is produced is thrown into the river (Researcher’s observations, 2024). Although these sectors support regional economic development and agricultural output, they also generate a significant amount of garbage, which poses major environmental problems and health risks to the general public. Developing efficient management plans and guaranteeing the sustainability of this vital water resource requires an understanding of the origins, makeup, and impacts of this industrial waste (Koul et al., 2022; Silva, 2023).

Figure 3. Shows the other side of the river used as a washing bay for vehicles and motorcycles.

The area is urban, just at the base of Kihihi town, in the valley down the town hill. The water from the washing bay may contain oils, chemicals, and other detergents that can have harmful effects on aquatic life in the river and contaminate the water. Water from the bay also makes the river less appealing for tourism and recreational purposes (Researcher’s observations, 2024). Urban environments often present unique challenges in managing the quality of water, particularly in areas close to where human activities such as vehicle and motorcycle washing take place. The Meizimera River, which is located at the base of Kihihi town, exemplifies these challenges, as nearby washing bays contribute to the contamination of its waters.

The runoff from these washing facilities can introduce a variety of pollutants, including oils, chemicals, and detergents, which can have detrimental effects on aquatic ecosystems. Such substances may not only harm aquatic life by disrupting physiological processes and habitats but can also lead to bioaccumulation of toxins within the food chain, posing risks to human health as well (Ali & Khan, 2019; Koul et al., 2022; Rajak et al., 2024; Ray & Shaju, 2023).

Furthermore, the presence of contaminants from washing activities diminishes the aesthetic and recreational value of the river, deterring tourism and negatively impacting local economies that rely on natural attractions (Researcher’s observations, 2024). This scenario underscores a broader issue faced by urban waterways, wherein the intersection of commercial and residential activities significantly compromises water quality. As urban areas continue to develop, it becomes increasingly essential to implement sustainable management practices and regulatory frameworks that address the pollution from washing bays and similar sources. Failing to do so risks not only the health of local aquatic ecosystems but also the economic viability of tourism and recreation, which are vital to the community’s prosperity and well-being.

Figure 4. Shows the industrial dumping of their by-products and leaking oils at the bank of the river.

These can easily be eroded into the water. These have a devastating effect on the environment, aquatic life, and also human health (Researcher’s observations, 2024). The arrow on the image indicates where the bi-product site and the site where the leaking oils are located. The Meizimera River in Kihihi, Uganda, is a critical natural resource that has the potential to enhance the quality of life for local communities and stimulate economic growth through recreational activities. However, pollution and contamination have severely limited these opportunities (Barinova et al., 2020; Kibria et al., 2023). If restored to a healthier state, the river could support a range of recreational pursuits, such as fishing, boating, swimming, and ecotourism, attracting both residents and visitors alike (France, 2011; Jennings, 2007). This revitalization would not only improve public health and well-being associated with increased physical activity and access to outdoor spaces (Zabielaitė-Skirmantė et al., 2023) but also bolster local businesses and create jobs, highlighting the importance of sustainable environmental management in preserving this vital waterway (Li et al., 2024; Wang et al., 2024).

Figure 5. Domestic wastes from the town are eroded down the hill to the river, while others are dumped directly into the river.

People who live along the river wash their clothes and household utensils and discharge their sewage into the water body. Farming occurs along the riverbank, and some soil is eroded into the river. The river is seen to be fertile at the old stage point of the river with a slightly green appearance, indicating the growth of algae and other vegetation (Researcher’s observations, 2024). The Meizimera River in Kihihi, Uganda, serves as a crucial ecological and social resource for local communities. However, it faces significant challenges due to environmental degradation from domestic waste, agricultural runoff, and inadequate waste management practices. Observations show that domestic waste from the nearby town is either eroded down the hillsides into the river or dumped directly into the waterway, resulting in increased pollution levels and negative impacts on water quality (Chakraborty & Chakraborty, 2021; Kienja, 2017; Kumar et al., 2019). Residents along the river frequently wash clothes and household utensils, while the direct discharge of sewage into the river further exacerbates contamination (Deb et al., 2021; Hamner et al., 2006; Hoque et al., 2021).

Farming activities along the riverbanks contribute to soil erosion, adding to the sediment load and compromising the river’s health (Hayes et al., 2024; Kondolf et al., 2018). Notably, the river exhibits a slightly green appearance at certain points, indicating the presence of algae growth and potentially highlighting nutrient enrichment, a process known as eutrophication (Brush et al., 2020; Hilton et al., 2006; Human et al., 2018). While this algal growth may suggest fertility, it is essential to investigate whether the observed green coloration is a common occurrence or an unusual phenomenon, as excessive algae can indicate declining water quality rather than ecological balance.

Furthermore, the presence of plastic waste, particularly green bottles, raises concerns about pollution and its sources. Although these plastics might not be unique to this area, their accumulation highlights gaps in local waste management practices. While trash collectors are operating in the vicinity, the effectiveness of their efforts in reducing plastic waste and promoting recycling remains uncertain. Recycling initiatives could significantly mitigate the impact of plastics in the river, but their implementation and community engagement play pivotal roles (Khalid & Ullah, 2022; Kumar et al., 2021; Sandu et al., 2020). Turning attention to these factors is crucial to designing sustainable management strategies for the Meizimera River, ensuring its health for future generations.

Figure 6. Shows a fully established water plant community that has completely succeeded in the river.

Water plant growth in rivers leads to oxygen depletion, nutrient competition, and the obstruction of recreational activities (Researcher’s observations, 2024).

The Meizimera River in Kihihi, Uganda, serves as a critical resource for both the local ecosystem and the communities surrounding it. However, recent observations indicate that the river’s health is under severe threat due to the proliferation of water plants and contamination from plastic waste, particularly green plastic bottles. The extensive growth of aquatic vegetation signifies an alteration in the river’s ecological balance and can lead to several complications, including oxygen depletion, nutrient competition, and interference with recreational activities (Chakraborty & Chakraborty, 2021; Lacoul & Freedman, 2006; Malmqvist & Rundle, 2002). While such water plant communities can sometimes indicate nutrient enrichment, often associated with pollution, their dominance in the river raises concerns about habitat quality and the potential for detrimental effects on fish and other aquatic organisms (Bănăduc et al., 2022).

Furthermore, the presence of plastic waste, particularly in the form of green plastic bottles, poses additional challenges to the river’s integrity. These plastic pollutants not only detract from the aesthetic and recreational value of the river but also have implications for aquatic life and human health (Yose et al., 2023). It is important to determine whether these plastics are a persistent issue in the river or an unusual accumulation resulting from recent activities. While they are a common form of waste, the degree of their presence and the effectiveness of local waste management practices, including recycling initiatives, remain critical points for investigation (Ben-Haddad et al., 2024; Singh et al., 2024). Addressing these environmental challenges through sustainable management and community engagement is essential for restoring the ecological balance of the Meizimera River and safeguarding it for future generations.

Policy outcomes

Implementing effective policies and strategies can have a profound impact on the environment and local communities. By reducing pollution levels and improving water quality, we can create a healthier environment and decrease the incidence of waterborne diseases (Levy et al., 2018), leading to improved health and well-being for residents. Moreover, clean water can support various economic activities such as fisheries and tourism, generating income and stimulating local economic growth. Successful policies can also protect biodiversity, preserve ecosystem balance, and maintain the natural beauty of the river (Arthington et al., 2010).

Effective policies can foster community involvement, raise awareness, and promote collective action to address water pollution (Bisung, 2021). Additionally, they can ensure efficient use of water resources, reducing waste and promoting sustainable practices. By achieving clean water and sanitation (SDG 6), we can contribute to the broader sustainable development goals. Successful policies can be replicated and scaled up to address water pollution in other districts, supporting national and global efforts to protect water resources and ensure a sustainable future for all.

Implications

The research on water pollution in the River Meizimera Kihihi has important ramifications for future research, policy and governance, human health, the environment, and communities and society. It emphasizes the necessity of more stringent regulations, stepped-up enforcement, community involvement, and ongoing monitoring to address the causes and effects of pollution and guarantee sustainable development. Significant implications of the study include increased risk of waterborne illnesses and long-term health effects; environmental degradation, including harm to aquatic life and ecosystems; economic impacts, including loss of income and livelihoods; community and social impacts, including improved quality of life; and future research directions, emphasizing the need for community engagement, ongoing monitoring, and evidence-based solutions to address the causes and effects of pollution and support economic growth.

The research conducted on water pollution in the River Meizimera in Kihihi, Uganda, reveals significant negative impacts that extend across multiple facets of human health, environmental sustainability, economic stability, and social well-being. The escalating pollution levels in this vital waterway underscore the urgent need for more stringent regulations and enhanced enforcement mechanisms to effectively combat the root causes of contamination. High levels of pollutants in the river have been linked to an increased risk of waterborne illnesses, which pose grave health threats to local communities, particularly in marginalized populations that depend on this water for daily use (Hamner et al., 2006; Lin et al., 2022). Such health risks not only lead to immediate concerns over the welfare of individuals but also have long-term effects, potentially overwhelming local healthcare systems and diminishing overall community resilience.

Environmental degradation is another major consequence of water pollution, with documented harm to aquatic life and ecosystems that are crucial for maintaining biodiversity and ecological integrity (Akhtar et al., 2021; Madhav et al., 2020). The river’s vitality is compromised by nutrient runoff from agricultural practices, contributing to toxic algal blooms that deplete oxygen levels and disrupt aquatic habitats (Roger, 1982; Siman & Niewiarowski, 2023). This degradation subsequently affects not only the flora and fauna within the river but also the livelihoods of those who depend on these natural resources for sustenance and income. Research has indicated that pollution-related declines in fish populations can lead to significant losses of income for local fisherfolk, further exacerbating poverty levels and undermining community stability (Onyenekwe et al., 2022; Tuler et al., 2008).

As the region grapples with the dual challenges of agricultural runoff and untreated wastewater, the development and enhancement of water management infrastructure are crucial. However, these changes can impart pollution if not carefully designed and implemented. For instance, the construction of sewage treatment facilities is essential for managing domestic wastewater; however, if these systems are outdated or poorly maintained, they can lead to the discharge of untreated sewage into the river, exacerbating pollution levels (Akpor et al., 2014; Hamdhani et al., 2020).

Moreover, as urbanization increases, the expansion of impervious surfaces such as roads and buildings can lead to heightened stormwater runoff, which carries sediments, nutrients, and pollutants directly into the river. The implementation of effective stormwater management systems, such as retention basins and green infrastructure, is necessary to mitigate this runoff. However, the likelihood of successfully integrating such systems into existing urban landscapes often faces substantial challenges, including financial constraints, limited space, and the need for ongoing maintenance (Aronson et al., 2017; Bandarin & Van Oers, 2012). In many cases, local governments may lack the resources or political support to prioritize these infrastructure improvements, resulting in a continued reliance on outdated systems that fail to adequately protect water quality.

Additionally, industrial infrastructure in the region poses its own set of challenges. Industries along the Meizimera River may discharge pollutants if they lack adequate waste management systems. The push for modernization and compliance with environmental regulations can be met with resistance, as industries may perceive the costs associated with upgrading their infrastructure as burdensome. This reluctance underscores the need for governmental incentives and support to encourage industries to adopt cleaner technologies and practices that reduce their environmental footprint (Aliu et al., 2025; Subramanian & Abdulrahman, 2017).

Furthermore, policy enforcement and community engagement play critical roles in the success of infrastructure changes aimed at reducing water pollution. Inadequate coordination among governmental agencies, coupled with a lack of public awareness regarding the importance of water quality, can hinder the implementation of effective solutions. Engaging local communities in the planning and execution of infrastructure projects can foster a sense of ownership and accountability, ultimately enhancing the sustainability of these initiatives.

Moreover, the social ramifications of water pollution cannot be overlooked, as contaminated water sources contribute to a diminished quality of life for residents. Access to clean water is essential for health, hygiene, and daily activities, and the burden of using polluted water often falls disproportionately on vulnerable groups, leading to increased social inequities (Moe & Rheingans, 2006; Ray & Smith, 2021). This situation highlights the necessity for community engagement and ongoing monitoring efforts, as local knowledge and active participation are critical in developing effective solutions to address pollution and promote sustainable practices. Thus, this research not only emphasizes the urgent need for action but also serves as a call to prioritize collaborative, evidence-based approaches in future policy and governance frameworks aimed at ensuring both the health of the river and the well-being of its surrounding communities.

Current efforts to address the problem of water pollution in Mezimera Kihihi, Uganda

Therefore, the following strategies to address pollution in this and the world at large are as follows. The by-products from factories, the coffee and \rice husks, are sold to other industries where they can be made useful. In this case, two factory owners said these husks are taken to the Hima cement factory and also to the Mbarara Yoghurt industry, where they are used as a source of heat/fuel since they are good at storing heat/fire for a long period. This is because they are good insulators. The coffee husks are bought by many farmers who use them as a source of organic manure in gardens. So they are taken by those who bring coffee to the factory for other agricultural purposes and chicken feeds, hence reducing pollution of the area. There are strict orders for factory owners to collect their husks in a controlled space and avoid dumping them everywhere. The factories have shifted from using petrol and diesel as fuel to using electricity, which has reduced other forms of pollution.

Governments enact laws and regulations to control pollution, such as the Clean Water Act in the United States and the European Water Framework Directive in Europe. In Rwanda, plastic bags were banned from the market. NGOs and governmental organizations conduct awareness campaigns to educate the public about the importance of water conservation and pollution prevention. Advances in wastewater treatment technologies, for example, UV disinfection, pollution monitoring systems, and eco-friendly practices help mitigate pollution and improve water quality before discharge. International agreements and initiatives, such as the United Nations Sustainable Development Goals and the Paris Agreement, foster cooperation among nations to combat water pollution on a global scale (Javed et al., 2022; Zahoor & Mushtaq, 2023).

Recommendations

To address water pollution in River Meizimera –Kihihi, we recommend adopting sustainable agricultural practices, industrial processes, and waste management strategies to minimize water pollution. There should be enforcement mechanisms and penalties for polluters to ensure compliance with environmental regulations. Also, there should be awareness to educate the public about the importance of water conservation, pollution prevention, and responsible consumption to foster behavioral changes and community engagement. Investment in upgrading and expanding water treatment facilities, sewage systems, and stormwater management infrastructure will help to prevent pollution, safeguard water resources, and finally allocate resources to research institutions and initiatives focused on developing innovative solutions for water pollution control and management.

Ethics and consent

A consent form was signed by the LC chairperson of Kihihi Town Ward so that the research could be carried out in the community. Proof of the signed form by the LC is attached to this manuscript. The following steps were implemented to protect the rights of participants whose images appeared during observation. All participants were thoroughly informed about the goals and advantages of the study, and the participant gave their consent verbally with no written documents. The reason for verbal consent was that most of the participants in this research couldn’t write. The faces depicted in the image were de-identified, and participant identities were kept private. There was no ethical approval, but there was a consent form that was signed by the chairperson. Neither the environment nor the volunteers were harmed by the research. The community intended to gain from the research by having problems with water pollution and sustainable habits. Lastly, the study was conducted impartially, guaranteeing advantages for all parties involved.