Water Pollution: Understanding The Causes And Impacts

Water pollution is a pressing issue that poses a threat to aquatic ecosystems, human health, and the economy. It occurs when toxic substances, such as chemicals, waste, plastics, and other pollutants, contaminate water bodies like lakes, rivers, and oceans. These pollutants can come from various sources, including industrial waste, agricultural runoff, oil spills, and improper waste disposal. For instance, sewage and industrial waste discharge are among the most polluting sources, while indirect sources include contaminants from soils, groundwater, and atmospheric rainfall. With more than 80% of the world's wastewater flowing untreated back into the environment, it is essential to address water pollution to safeguard aquatic life, human health, and our limited freshwater resources.

Oil spills and leaks

The transportation and storage of oil are subject to leakage that pollutes water resources. Oil spills can be caused by the release of crude oil from tankers, offshore platforms, drilling rigs, and wells. They may also involve spills of refined petroleum products, such as gasoline and diesel fuel, as well as their by-products. Additionally, heavier fuels used by large ships, such as bunker fuel, or spills of any oily refuse or waste oil, contribute to such incidents.

Oil spills often have severe environmental and economic consequences. Oil on the ocean surface is harmful to many forms of aquatic life as it prevents sufficient sunlight from penetrating the surface, and it also reduces the level of dissolved oxygen. Oil spills can ruin a day at the beach and make seafood unsafe to eat. They can also have a significant impact on plant life, with saltwater marshes and mangroves being two notable shore ecosystems that frequently suffer from oil spills.

Oil spills can cause immediate negative effects on human health, including respiratory and reproductive problems, as well as liver and immune system damage. Oil spills can also lead to the closure of beaches, parks, and fisheries, and create fire hazards. The cleanup and recovery process after an oil spill is complex and time-consuming, often taking weeks, months, or even years.

Furthermore, oil spills can have significant social and economic repercussions. They can affect human-use resources, such as airports, diving sites, popular beach sites, marinas, hotels, factories, natural reserves, or marine sanctuaries. Oil spills can also impact commercial fishing, recreational businesses, tourism, and property values, ultimately stalling economic growth and exacerbating poverty in many countries.

Industrial waste

Many industrial sites produce waste in the form of toxic chemicals and pollutants, and some do not have proper waste management systems in place. Sometimes, industrial waste is dumped into nearby freshwater systems. The toxic chemicals leached from this waste can make the water unsafe for human consumption, and they can also cause the temperature in freshwater systems to change, making them dangerous for marine life. For example, chlorobenzene is a carcinogenic hazardous substance used as a solvent in the textile industry.

The increased population has led to a higher demand for goods, which has caused rapid industrialization. This has resulted in an increased production of industrial waste, which causes major environmental havoc by polluting the water, air, and soil. The quality and quantity of wastewater generated depend on the type of industry, with some industries producing non-biodegradable waste such as heavy metals, pesticides, and plastics. Without proper treatment and management strategies, the discharge of this waste into water bodies can have dreadful environmental and health effects.

Agricultural chemicals

Agriculture is a major cause of water pollution, particularly in freshwater sources. As the single largest user of freshwater globally, agricultural activities have led to the degradation of surface and groundwater resources through erosion and chemical runoff.

Soil erosion, a consequence of agricultural activities, is another leading cause of water pollution. Erosion can result in excessive sedimentation, overwhelming aquatic ecosystems, smothering breeding areas, and degrading coastal ecosystems, including coral reefs. This sedimentation, along with nutrient loss and the runoff of pesticides and other contaminants, constitutes the primary stressors on water quality.

The use of veterinary medicines, including antibiotics, vaccines, and growth promoters, has emerged as a new class of agricultural pollutants. These medicines can move from farms into water sources and ecosystems, potentially impacting drinking water and downstream ecosystems.

The impacts of agricultural chemical pollution vary depending on factors such as the type of farming operation, landscape conditions, soils, climate, and farm management practices. However, it is evident that agricultural chemicals play a significant role in degrading water quality and the health of aquatic ecosystems.

Radioactive waste

Radioactive contamination, also known as radiological pollution, is the presence of radioactive substances on surfaces or within solids, liquids, or gases, including the human body. This contamination occurs when radioactive materials are accidentally or unintentionally released into the environment, presenting an environmental threat due to radioactive decay. Radioactive waste is produced by industrial, medical, and scientific processes that use radioactive materials.

Nuclear power plants, reprocessing plants, and the military are the main sources of radioactive waste. As the nuclear energy industry expands, the amount of radioactive waste disposed of each year increases. Nuclear waste has detrimental effects on marine habitats, and it is recognised that radioactive material must be isolated and encased to prevent leakage. Radioactive caesium and plutonium, for example, have been discovered in seals and porpoises in the Irish Sea. Radioactive waste can enter the food chain through plankton and kelp, eventually contaminating fish.

Radioactive pollution can also be caused by the disposal of nuclear weapons, cleaning materials from nuclear plants, military installations, and emissions from plutonium processing. Radioactive isotopes released by power plants, such as caesium, radon, crypton, ruthenium, zinc, and copper, can be detected in the soft tissues and bones of fish, as well as in seaweed used in bread. While the amount of waste released may be deemed "permissible," it does not imply it is safe. Radioactive waste contains radiation that can spread through air, water, and soil, making it difficult to target and eliminate.

Sewage and wastewater

Sources of Sewage and Wastewater

• Households: Sewage systems collect and convey wastewater from homes, including water from sinks, showers, and toilets. This wastewater contains human waste, bacteria, viruses, and parasites that can be harmful to human and animal health.
• Industries: Industrial processes generate large volumes of wastewater that can contain toxic chemicals, heavy metals, and other pollutants. Inadequate treatment or illegal discharge of this wastewater can contaminate rivers, streams, and oceans.
• Agriculture: Farms and livestock operations contribute wastewater that includes animal waste, fertilizers, and pesticides. When it rains, these contaminants can be washed into waterways, leading to nutrient pollution and algal blooms.
• Stormwater Runoff: Rainfall can carry oils, grease, chemicals, and debris from impermeable surfaces into waterways, contributing to water pollution.
• Septic Systems: Leaking septic systems can release untreated sewage into the environment, contaminating groundwater and surface water.

Impact of Sewage and Wastewater Pollution

The release of sewage and wastewater into water bodies can have significant environmental, health, and economic impacts:

• Environmental Impact: Sewage and wastewater pollution can disrupt ecosystems, reduce biodiversity, and kill aquatic life. Excess nutrients in wastewater can cause algal blooms, which block light for photosynthesis and reduce oxygen levels in the water, creating "dead zones" devoid of life.
• Health Impact: Sewage and wastewater contain pathogens, bacteria, and viruses that can breed diseases such as cholera, typhoid, and giardia. These contaminants pose risks to human health, affecting coastal economies that rely on clean water for tourism, recreation, and commercial fishing.
• Economic Impact: Polluted water can increase treatment costs, leading to higher drinking water prices. It can also impact property values and sectors that depend on clean water, such as tourism, recreation, and commercial fishing.

Preventing Sewage and Wastewater Pollution

To address sewage and wastewater pollution, it is essential to improve wastewater management and infrastructure:

• Wastewater Treatment: Increasing the treatment, recycling, and safe reuse of wastewater can reduce pollution and provide a sustainable source of water, energy, and nutrients.
• Infrastructure Maintenance: Upgrading and maintaining sewage infrastructure can prevent spills, overflows, and the discharge of raw or under-treated sewage into waterways.
• Reducing Plastic and Chemical Waste: Properly disposing of chemicals, oils, and non-biodegradable items can prevent them from entering waterways and contributing to pollution.

Frequently asked questions