Human Activities Polluting Fresh Water Sources

Water is essential for all living things, yet humans continue to pollute it. Water pollution occurs when harmful substances contaminate a body of water, degrading water quality and rendering it toxic to humans and the environment. The world's freshwater sources receive contaminants from a wide range of sectors, including agriculture, industry, and oil spills. In the United States, agricultural pollution is the leading cause of contamination in rivers and streams, while municipal and industrial waste discharges also contribute significantly to water pollution. Oil spills and leaks from pipelines or fracking operations can also degrade water supplies, and wind, storms, and littering, especially plastic waste, can send debris into waterways. Additionally, the burning of fossil fuels releases compounds that interact with the air, creating acid rain that pollutes water sources. With only a small percentage of freshwater easily accessible, preventing water pollution is crucial to ensure the health and well-being of humans and ecosystems alike.

Agricultural pollution

Agriculture is the leading cause of water degradation worldwide. The sector is the biggest consumer of global freshwater resources, with farming and livestock production using about 70% of the earth's surface water supplies.

Agricultural activities discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into water bodies. These pollutants include bacteria, viruses, parasites, fertilisers, pesticides, pharmaceuticals, nitrates, phosphates, plastics, and faecal waste.

Fertilisers and pesticides are responsible for nutrient pollution, which is the number-one threat to water quality worldwide. Excess nitrogen and phosphorus in water or air can cause algal blooms, a toxic soup of blue-green algae that can be harmful to people and wildlife. Nitrates in water can also cause "blue baby syndrome", a potentially fatal illness in infants. In addition, pesticides can be harmful to human health, with atrazine, one of the most widely used and widely detected pesticides in surface water, being linked to increased cases of stunted growth in children.

Livestock production accounts for 70% of all agricultural land and 30% of the planet's land surface. Animal waste from farms and livestock operations washes nutrients and pathogens, such as bacteria and viruses, into our waterways every time it rains.

Agricultural expansion and intensification have led to changes in water quality and the health of stream ecosystems. The area equipped for irrigation has more than doubled in recent decades, transferring agricultural pollution to water bodies.

Oil spills and leaks

The implications of oil spills on freshwater systems and their surrounding environments are still not fully understood. Oil is a complex mixture of chemicals whose nature changes over time, and this can affect its behaviour in water, including whether it floats or sinks, as well as its potential toxicity to freshwater wildlife. For example, within 24 hours of an oil spill, volatile hydrocarbons can quickly evaporate, causing the oil to become denser and thicker, which can eventually lead to it sinking. This knowledge is critical for those responding to and cleaning up oil spills.

To address the lack of understanding of oil spills in freshwater systems, researchers at the International Institute for Sustainable Development's (IISD) Experimental Lakes Area (IISD-ELA) have initiated a groundbreaking project. This project involves conducting controlled experiments in a real lake using enclosures called "limnocorrals" to simulate oil spills. By studying the behaviour of oil and its effects on the ecosystem, researchers aim to improve our understanding of the impact of oil spills on freshwater systems and develop more effective cleanup techniques.

While some methods exist to clean up oil spills, such as using skimmers or chemical dispersants, there is still a lot of progress to be made in terms of reducing oil pollution and improving our ability to remediate it. Proper disposal of oil, paint, and hazardous chemicals is crucial, as anything that goes down storm drains can end up in bodies of water without proper treatment. Additionally, reducing our reliance on oil and transitioning to more sustainable energy sources can help mitigate the risks associated with oil spills and leaks.

Industrial waste

The production of industrial goods generates wastewater contaminated with toxic substances. This wastewater is often discharged into nearby public waters, including rivers, lakes, and seas. In some cases, this discharge is illegal and occurs due to a lack of consistent implementation and monitoring of environmental legislation. Even when treated, the pollutants are not always effectively removed, and the water may still be unsuitable for human consumption or use.

The types of industrial waste generated include cafeteria garbage, dirt and gravel, masonry and concrete, scrap metals, trash, oil, solvents, chemicals, weed grass and trees, wood and scrap lumber, and similar wastes. Certain commercial products, such as cleaning fluids, paints, or pesticides, can also be classified as hazardous waste if improperly discarded.

The release of industrial waste into water systems has severe consequences. Many hazardous substances from industry are challenging to biodegrade and accumulate in water sediments, harming fish, crustaceans, and other aquatic life. These pollutants can also infiltrate groundwater, making it unsafe for drinking and leading to poor sanitation and health issues in humans.

To address industrial water pollution, effective wastewater treatment systems are essential. Industries should aim to prevent and reduce pollution by implementing strategies such as recycling, reusing treated wastewater, and adopting more eco-friendly and sustainable practices. Additionally, strict regulations and consistent enforcement are necessary to ensure industries comply with environmental standards and protect water sources from contamination.

Plastic pollution

Research has revealed the presence of plastics in various freshwater ecosystems, including rivers, sediment, and areas associated with inland waters. This pollution has consequences for freshwater biodiversity, with evidence of plastic ingestion by numerous freshwater species, from invertebrates to mammals, and entanglement in plastics, particularly among birds. The presence of plastics in tap water, bottled water, and beer has also been detected, indicating the extent of plastic pollution in freshwater sources.

The impact of plastic pollution in freshwater ecosystems is complex and far-reaching. Plastics can alter habitats and natural processes, reducing ecosystems' ability to adapt to climate change. It directly affects the livelihoods, food production capabilities, and social well-being of millions of people. The environmental, social, economic, and health risks associated with plastic pollution need to be addressed alongside other environmental concerns.

To mitigate plastic pollution in freshwater ecosystems, coordinated actions are necessary. This includes implementing recycling programs, improving waste management practices, enforcing correct disposal methods, and developing stringent legislation with regular inspections. Additionally, replacing synthetic polymers with alternative materials and ecological restoration can help restore freshwater ecosystems.

It is important to recognize that plastic pollution in freshwater has received less research attention compared to marine plastic pollution. This disparity may be due to the later emergence of freshwater plastic pollution as a field of study. However, it is crucial to address this knowledge gap and prioritize research on plastic pollution in freshwater ecosystems to effectively tackle this global issue.

Sewage

The impact of sewage on the environment is devastating. Sewage encourages the growth of algae, leading to algal blooms that block light necessary for plant photosynthesis. As the plants and algae die, they are consumed by bacteria, reducing oxygen levels in the water and killing fish and other organisms, such as freshwater insects like stoneflies and mayflies, which are particularly sensitive to low oxygen conditions.

To address sewage pollution, it is crucial to invest in updating wastewater infrastructure and expanding natural areas to prevent stormwater from rushing into sewers. Strong notification programs are also essential to alert people to the presence of raw sewage in their waterways. By taking these measures, we can protect human health and the fragile river ecosystems that depend on clean water.

Additionally, sewage pollution has severe economic consequences. Contaminated water harms the economy of affected countries and regions. When the biological demand for oxygen increases, GDP decreases significantly. Exposure to nitrates can have lethal effects and hinder children's development.

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