Water Pollution: Understanding Key Differences And Their Impact

Water pollution is a pressing issue that jeopardizes the health of millions of people and aquatic life worldwide. It occurs when harmful substances contaminate water bodies, degrading water quality and rendering it toxic or unfit for human use. This contamination can be caused by various sources, including toxic waste, petroleum, industrial activities, agricultural runoff, and urban stormwater. When discussing water pollution, it is essential to differentiate between point sources and non-point sources. Point sources, such as storm drains or wastewater treatment plants, have a single identifiable cause, while non-point sources, like agricultural runoff or urban stormwater, are more diffuse and challenging to control. Understanding these differences is crucial for developing effective strategies to combat water pollution and protect our finite drinkable water sources.

Point source vs non-point source

Water pollution is the contamination of water bodies, causing a negative impact on their use. It is usually a result of human activities, but it can also be caused by natural factors. Water pollution can be categorised into two types: point source and non-point source.

Point Source

Point sources of water pollution refer to instances where harmful substances are emitted directly into a body of water. These sources have one identifiable cause, such as a storm drain, a wastewater treatment plant, or an oil spill. Other examples include sewage discharges, industrial activities, and urban runoff. Point sources are easier to control than non-point sources because the contaminated water is collected and conveyed to a single point for treatment.

Non-Point Source

Non-point sources of water pollution deliver pollutants indirectly through transport or environmental changes. These sources are more diffuse, such as agricultural runoff, which occurs when rainwater carries fertilisers and pesticides from farm fields into nearby water sources. Other examples of non-point sources include industrial waste from agricultural sites, mines, and manufacturing plants, as well as urban stormwater runoff, which can contain various pollutants.

Examples of Point Source and Non-Point Source Pollutants

Point source and non-point source pollutants can include a range of toxic substances such as oil, metals, plastics, pesticides, and industrial waste products. They can also include stressful conditions, such as changes in pH, hypoxia, increased temperatures, and excessive turbidity. Additionally, the introduction of pathogenic organisms, including bacteria, viruses, and parasites, can be a significant contributor to water pollution from both point and non-point sources.

Impact of Water Pollution

Water pollution has severe consequences for human health, the environment, and the economy. It can cause waterborne diseases, such as diarrhoea, cholera, dysentery, typhoid, and poliomyelitis, leading to hundreds of thousands of deaths worldwide each year. Water pollution also disrupts aquatic ecosystems, threatening the survival of various species and reducing biodiversity. Furthermore, it can stall economic growth and exacerbate poverty, especially in regions heavily reliant on water-related industries.

Human activity vs natural causes

Water pollution is a global issue that affects one in every three people on the planet, according to the United Nations. It is defined as the contamination of water bodies, including lakes, rivers, oceans, and reservoirs, which results in negative impacts on their use. While water contamination may occur naturally, water pollution is primarily caused by human activities and their consequences.

Human Activities

The most common cause of water pollution is human activity, which can introduce harmful substances into water bodies, rendering them toxic and unfit for human use. These activities include:

• Sewage Discharges: Untreated or inadequately treated sewage can contain high levels of bacteria, viruses, and other pathogens, which can cause waterborne diseases such as diarrhoea, cholera, and typhoid.
• Industrial Activities: Industrial sites produce toxic chemicals and waste that can contaminate nearby water systems. This includes chemical dumping, which can lead to eutrophication, and the release of heavy metals and other pollutants.
• Agricultural Activities: Farms and livestock operations contribute to water pollution through the use of fertilizers, pesticides, and animal waste, which can wash into water bodies during rainfall.
• Urban Runoff: Stormwater runoff can carry pollutants such as petroleum, oil, and plastic into water bodies, contributing to the degradation of aquatic ecosystems.
• Oil Spills: Leaks and spills from oil drilling operations or ships can have devastating impacts on marine life and ecosystems.
• Marine Dumping: Many countries still dispose of household garbage and industrial waste directly into the ocean, leading to the contamination of water bodies.

Natural Causes

While human activities are the primary drivers of water pollution, there are also natural causes that can contribute to water contamination:

• Mercury Filtration: Mercury naturally filters from the Earth's crust, polluting oceans, rivers, and other water bodies.
• Geological Processes: Natural geological processes, such as volcanic eruptions or earthquakes, can release pollutants into water bodies.
• Weather Events: Storms, floods, or other weather events can cause the dispersal of pollutants, leading to water contamination.
• Algal Blooms: While sometimes caused by human activities, algal blooms can also occur naturally and impact water quality.
• Radioactive Decay: The natural decay of radioactive materials in the environment can result in the contamination of water sources.

Water pollution vs water contamination

Water pollution and water contamination are two different concepts, with the former being a more specific case of the latter. Water contamination refers to the presence of impurities in water, regardless of the source or events that led to the impurities being in the water. A common impurity or contamination in water is its Total Dissolved Solids (TDS) count. TDS consists mainly of carbonates, dissolved bicarbonates, chlorides, sulfates, phosphates, nitrates, calcium, magnesium, sodium, potassium, iron, manganese, and a few others.

Water pollution, on the other hand, is the addition of substances or energy forms that directly or indirectly alter the nature of the water body, impairing its legitimate uses. Water is typically referred to as polluted when it is impaired by anthropogenic contaminants. Due to these contaminants, it either no longer supports a certain human use, such as drinking water, or undergoes a marked shift in its ability to support its biotic communities, such as fish. The main water pollutants include bacteria, viruses, parasites, fertilisers, pesticides, pharmaceutical products, nitrates, phosphates, plastics, faecal waste, and even radioactive substances.

Water pollution can be further categorised into two types: point source and non-point source. Point source pollution occurs when harmful substances are emitted directly into a body of water, such as a pipe from an industrial facility discharging effluent directly into a river. Non-point source pollution delivers pollutants indirectly through transport or environmental change, such as when fertilizer from a farm field is carried into a stream by rain.

The consequences of water pollution are far-reaching and impact human health, the environment, and the economy. Unsafe water kills more people each year than war and all other forms of violence combined. It also jeopardises our drinkable water sources, which are already finite, with less than 1% of the earth's freshwater being accessible. Water pollution also damages the environment, with marine debris strangling, suffocating, and starving animals, and ocean acidification making it tougher for shellfish and coral to survive. Lastly, water pollution harms the global economy, with deteriorating water quality stalling economic growth and exacerbating poverty in many countries.

Oil spills and leaks

Oil is a toxic substance that does not dissolve in water. When oil is spilled or leaked into bodies of water, it contaminates them, rendering them toxic and unsafe for human use. This type of pollution can lead to the degradation of aquatic ecosystems and the spread of water-borne diseases when people use the polluted water for drinking or irrigation. Oil spills can also cause eutrophication, a process where aquatic life cannot survive due to a lack of oxygen.

The effects of oil spills and leaks on aquatic life can be devastating. Oil can coat the feathers or fur of animals, reducing their ability to insulate, leading to hypothermia. It can also impair their ability to hunt and move through the water, and block their breathing passages. Oil spills can also destroy the habitats of marine organisms, such as coral reefs and mangroves, and reduce biodiversity.

To prevent and mitigate the impacts of oil spills and leaks, proper waste management systems, infrastructure and management plans, as well as legislation, are necessary. It is important to prioritize the protection of water resources, as they are essential for sustaining life and supporting social and economic development.

Industrial waste

Industries and industrial sites are a major contributor to water pollution. Many industrial processes use water, which comes into contact with harmful chemicals. These include organic compounds, metals, nutrients, or radioactive material. If the resulting wastewater is discharged without treatment, it can pollute groundwater and surface water bodies, including lakes, streams, rivers, and coastal waters. This can have serious impacts on human health, the environment, and the economy.

The effects of water pollution from industrial waste are devastating to people, animals, fish, and birds. Contaminated water is unsafe for drinking, recreation, agriculture, and industry. It also diminishes the aesthetic quality of lakes and rivers, destroys aquatic life and reduces its reproductive ability, and fosters the invasion of new thermophilic species.

While legislation and regulations exist to address industrial waste and water pollution, compliance varies across countries and industries. Many industrial sites, particularly small-scale industries, lack proper waste management systems due to financial constraints. This results in the dumping of untreated waste into nearby freshwater systems, causing water pollution.

To mitigate the impact of industrial waste on water pollution, several strategies can be employed:

• Waste minimization: Reducing the production of hazardous waste and its toxicity levels through source reduction and recycling.
• Treatment and disposal: Ensuring that wastewater is treated or clarified before being discharged into sewage systems or bodies of water.
• Compliance and enforcement: Strengthening the implementation and monitoring of existing legislation and regulations to prevent illegal discharges.

Frequently asked questions