Water Pollution: A Historical Perspective On Our Mistakes

Water pollution is a pressing issue that has been affecting our planet for centuries. It occurs when harmful substances contaminate bodies of water, degrading water quality and rendering it toxic to humans, animals, and the environment. While water pollution has been a concern since the 1800s, it has become an increasingly pressing issue due to industrialization, agricultural practices, and improper waste disposal. Today, our rivers, lakes, and oceans are inundated with chemicals, waste, plastics, and other pollutants, posing a significant threat to aquatic ecosystems, human health, and the economy. Understanding the history of water pollution and its causes is crucial to address this global challenge and find sustainable solutions.

Industrial and municipal discharge

Water pollution is caused by a variety of factors, including industrial and municipal discharge, runoff, spills, and the deposition of airborne pollutants. Industrial and municipal wastewater discharges have a significant impact on surface water quality, which affects both human and ecosystem health.

Industrial Discharge

Industrial wastewater discharges can contain a range of pollutants, including heavy metals, motor oil, refractory organic compounds, and radioactive materials. The amount and type of industrial discharge can vary depending on the size and type of industry, as well as the level of treatment applied before discharge into sewers. In response to regulations and local sewer surcharges, there has been an increasing trend towards mandating pretreatment of wastewater in the United States. While industrial point sources of water pollution have declined in developed economies due to national efforts and regulations, they still contribute significantly to water pollution in many countries.

Municipal Discharge

Municipal wastewater treatment plants are responsible for treating sewage and stormwater before discharging it into nearby water bodies. However, in some cases, municipal wastewater treatment plants may struggle to keep up with the volume of wastewater, especially during heavy rainfall or snowmelt, leading to the discharge of untreated sewage. In 2018, the Environmental Protection Agency (EPA) in the United States estimated that nearly 11,000 industrial facilities and municipal wastewater treatment plants had illegally dumped significant amounts of pollution into nearby water bodies.

Combined Sewer Systems

Hundreds of municipalities in the United States have combined sewer systems, where sewage and stormwater are combined in a single pipeline. These systems can contribute to water pollution during heavy rainfall or snowmelt events, as they may discharge untreated sewage into nearby water bodies. In 2020, more than 700 municipalities with combined sewer systems obtained permits from the EPA to discharge pollutants, with limits set on the amount of pollution allowed. However, it is important to note that the EPA's focus has primarily been on tracking compliance rates rather than the overall effect of improved compliance on water quality.

Agricultural waste

Agriculture is a major contributor to water pollution, accounting for 70% of water withdrawals worldwide. Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into water bodies. This includes pesticides, fertilisers, antibiotics, and other veterinary medicines.

One of the main ways that agricultural waste enters water sources is through runoff. Rainfall and snowmelt can carry pollutants such as soil erosion, nutrient loss, bacteria from livestock manure, and pesticides into local streams, rivers, and groundwater. This can lead to eutrophication, which is caused by the accumulation of nutrients in lakes and coastal waters and impacts biodiversity and fisheries.

Another issue is the use of manure, which can contain high levels of phosphorus, leading to phosphorus runoff that harms waterways. Livestock and poultry in the United States produce nearly 1.4 billion tons of manure annually, which is often spread on land untreated. This can result in excessive amounts of nutrients entering water sources, as well as the presence of heavy metals like copper and zinc, which are fed to pigs and chickens as supplements. These metals can accumulate in the soil and contaminate water supplies, causing health problems for humans and the environment.

To mitigate these issues, buffer strips of vegetated filter strips at the margins of farms and along rivers can be effective in decreasing concentrations of pollutants entering waterways. Integrated farming, where waste from one enterprise becomes inputs for another, can also help reduce pollution and optimise resource use. Additionally, practices such as drip irrigation instead of furrow irrigation can decrease water loss and allow better control of pesticide and nutrient amounts.

Sewage and wastewater treatment

Water pollution occurs when harmful substances, often chemicals or microorganisms, contaminate a body of water, degrading water quality and rendering it toxic to humans or the environment. Sewage and wastewater are some of the main sources of water pollution.

Wastewater treatment facilities process water from homes and businesses, removing many pollutants from the water. However, even after treatment, wastewater can still contain high levels of nitrogen and phosphorus, which can lead to nutrient pollution when the water is released into local water bodies.

In the United States, approximately 34 billion gallons of wastewater are processed daily, with around 20% of homes using septic systems to locally treat their wastewater. Septic systems can become a source of nutrient pollution if not properly maintained, with elevated levels of nitrogen and phosphorus released into local water bodies or groundwater.

The treatment and disposal of sewage and wastewater are significant challenges, especially in certain regions. In the Caribbean, for instance, untreated sewage is considered one of the main sources of degradation of the coastal environment. In Haiti, there are no sewage collection services, and a significant portion of the population dumps human waste illegally into rivers and seas, leading to harmful health and environmental consequences.

To address these issues, various strategies are being pursued to improve sewage and wastewater treatment. These include implementing treatment options that protect carbon-storing ecosystems, diverting waste into valuable resources, and developing national planning mechanisms to control marine pollution from sewage and wastewater.

It is important to note that individual actions, such as reducing plastic consumption, properly disposing of chemicals, and maintaining vehicles to prevent leaks, can also play a significant role in reducing sewage and wastewater pollution.

Oil spills

Accidents involving tankers, barges, pipelines, refineries, drilling rigs, and storage facilities are the most common cause of oil spills. Natural processes can also cause oil spills, as oil can seep from the bottom of the ocean and from eroding sedimentary rocks. Oil spills can have severe environmental, economic, and social consequences. They can harm sea creatures, make seafood unsafe to eat, ruin beaches, and cause respiratory and reproductive problems in humans, as well as liver and immune system damage. The cleanup and recovery process after an oil spill is challenging and can take weeks, months, or even years.

One notable example of an oil spill is the Deepwater Horizon spill in 2010, which was the largest oil spill in U.S. waters. Another example is the Exxon Valdez oil spill, which resulted in press releases and reports from the United States Environmental Protection Agency. While technologies for drilling in deep water have improved, oil companies are moving to more challenging drilling sites, making it difficult to determine any clear trend in the frequency of offshore oil platform spills.

To address oil spills, organizations like the Safe Water Foundation work to raise awareness and provide educational resources. MARPOL, which came into effect in 1983, has also contributed to a significant reduction in oil spills, particularly in the United States, by implementing regulations such as limiting the size of individual tanks within ships and prohibiting discharges within certain distances of land.

Air pollution

According to the World Health Organization (WHO), indoor and outdoor air pollution causes nearly seven million deaths annually worldwide. Ninety-nine per cent of humans currently breathe air that exceeds the WHO's guideline limits for pollutants, with those in low- and middle-income countries suffering the most. To combat this, the Clean Air Act of 1990 sets limits on the discharge of air pollutants from industrial facilities and motor vehicles, and addresses acid rain and ozone depletion. These laws have significantly reduced pollution.

Additionally, individuals can reduce air pollution by limiting car usage, using public transportation, choosing fuel-efficient or electric cars, and supporting leaders who advocate for clean air and responsible climate change policies. Carpooling, using mass transit, and adopting hybrid vehicles can also help lower carbon footprints and improve air quality.

Moreover, environmental disasters, such as oil spills, and industrial waste discharges contribute to both air and water pollution. The 1989 Exxon Valdez oil spill off the coast of Alaska is an example of a man-made disaster that devastated the area's wildlife and ecosystems.

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