Industrial Waste And The World's Most Polluted Bodies Of Water

Water pollution is a pressing issue, with human intervention causing contamination through sewage, industrial waste, and agricultural runoff. The Pacific Ocean is the most polluted of the five official oceans, with the Great Pacific Garbage Patch spanning 1.6 million square kilometres. The Indian Ocean also has a garbage patch, covering five million square kilometres. The Yangtze, Ganges, Huangpu, and Salween are among the world's most polluted rivers, with industrial and agricultural waste being key contributors. In the US, the Mississippi, Ohio, and Jersey Shore waters are highly polluted, impacting aquatic life and human health.

Industrial and agricultural runoff

Industrial Runoff

Industrial runoff is the discharge of untreated or partially treated wastewater from industrial facilities into nearby water bodies. This can include a range of contaminants, such as heavy metals, toxic chemicals, oil, and industrial waste. For example, factories along the Yangtze River in China discharge industrial wastewater, contributing to it being one of the most polluted rivers in the world. Similarly, steel plants along the Ohio River in the United States release toxins like nitrate compounds and mercury, making it one of the ten most polluted waterways in the country.

Agricultural Runoff

Agricultural runoff is the result of excess fertilizers, pesticides, and manure from farms entering nearby water sources. This type of pollution is common in areas with intensive agriculture, where large amounts of animal waste, chemical fertilizers, and pesticides are used. For instance, the Mississippi River in the United States, which flows through America's agricultural heartland, experiences significant agricultural runoff, with chemical fertilizers and animal waste polluting the river and affecting nearby groundwater supplies. Similarly, the Ganges River in India, a sacred waterway, becomes increasingly contaminated as it flows downstream, collecting urban sewage, animal waste, pesticides, fertilizers, and industrial metals.

Combined Effects

In some cases, industrial and agricultural runoff combine to create even more severe pollution problems. This is often seen in areas with a high concentration of industrial facilities and agricultural activities, such as factory farms. For example, the Jersey Shore in the United States suffers from high levels of industrial and agricultural runoff, with the nearby ocean appearing gray-brown instead of blue due to the pollution. Similarly, the Río Grande in the United States experiences industrial tipping and agricultural runoff due to water extraction for agricultural and domestic use, causing a decrease in its volume.

Environmental and Health Impacts

Sewage and wastewater treatment

The treatment of sewage and wastewater involves removing impurities before the water reaches natural bodies of water such as rivers, lakes, estuaries, and oceans. This process began to be implemented in the late 19th and early 20th centuries, particularly in the United Kingdom and the United States, where centralized sewage treatment plants were constructed. These plants use a combination of physical, biological, and chemical processes to remove pollutants from the water. Additionally, new sewage collection systems were designed to separate stormwater from domestic wastewater, ensuring that treatment plants did not become overwhelmed during periods of heavy rainfall.

However, the increasing population and industrialization have also led to more significant challenges in treating sewage and wastewater. In densely populated areas, the volume of sewage generated can exceed the capacity of natural dilution processes, requiring more advanced treatment methods. Contaminants in wastewater can include organic matter, suspended solids, nutrients, chemicals, and microbial agents. Treating wastewater effectively helps control water pollution and protects aquatic ecosystems, ensuring water sources are safe for drinking, swimming, and other activities.

To design effective sewage treatment processes, decision-makers consider technical and economic factors. The "per person organic matter load," or population equivalent (PE), is a critical parameter in this design process. It represents the amount of biochemical oxygen demand (BOD) per person per day and is used to compare the strength of industrial wastewater to sewage. The base value for PE varies internationally, with 1 PE commonly equating to 60 grams of BOD per person per day and 200 liters of sewage per day.

In recent years, there has been a push for stricter discharge regulations and the implementation of the polluter pays principle. For example, Switzerland has set a target for the removal of key substances between the sewage treatment plant and the water body, with at least 80% of 6 out of 12 key substances required to be removed. Additionally, the municipal wastewater treatment sector is working towards becoming energy neutral by 2045, and the emission of microplastics and PFAS is being monitored. These efforts aim to improve the treatment of sewage and wastewater, reducing their impact on the environment and human health.

Farming and fossil fuel power plants

Our oceans, rivers, and lakes are being contaminated by chemicals, waste, plastics, and other pollutants. Nearly half of the rivers and streams and more than one-third of the lakes are polluted and unfit for swimming, fishing, and drinking. While plants and animals need nutrients like nitrates and phosphates to grow, they have become a major pollutant due to farm waste and fertilizer runoff. Municipal and industrial waste also contribute significantly to water pollution.

Farming has been a major contributor to water pollution, especially through nutrient pollution, which includes nitrates and phosphates. This type of pollution has led to eutrophication, a process where lakes become enriched with minerals and nutrients, causing a decrease in water quality and the formation of toxic algae blooms. Excessive fish farming has also contributed to this process, further degrading water quality.

Farm waste and fertilizer runoff containing pesticides, fertilizers, and chemicals contaminate nearby water sources, making them unsafe for human use and damaging local ecosystems. This has led to the decline of fish populations and the extinction of ancient animals, such as the Chinese paddlefish.

Fossil fuel power plants also contribute significantly to water pollution. Oil spills, such as the 2010 BP Deepwater Horizon spill in the Gulf of Mexico, have released massive amounts of oil into bodies of water, harming wildlife, destroying habitats, and polluting water sources. The burning of fossil fuels releases toxic particles and aromatic hydrocarbons, causing air pollution with severe health consequences, including asthma, cancer, heart disease, and premature death.

Additionally, the fracking process used in fossil fuel extraction can contaminate groundwater and drinking water with toxic substances like arsenic, lead, chlorine, and mercury. The plastic industry, heavily reliant on fossil fuels, produces significant plastic waste that ends up in oceans, killing marine life and polluting the food chain.

To address water pollution from farming and fossil fuel power plants, stricter laws and regulations are necessary to prevent agricultural and industrial industries from dumping waste into bodies of water. Governments must also invest in adequate waste management systems and support communities in properly disposing of their waste to reduce their contribution to water pollution.

Urbanisation, population growth, and fish farming

Population growth exacerbates water pollution by increasing water demand and scarcity. With a rising population, the finite supply of safe and accessible freshwater becomes strained, leading to water stress and scarcity. This is particularly evident in areas with high population densities and inadequate infrastructure, where the lack of clean drinking water can result in preventable deaths.

Urban development involves the construction of roads, buildings, and industrial sites, which can have detrimental effects on local water bodies. Urbanisation alters natural landscapes, leading to increased wastewater discharge into local streams and rivers. The expansion of pavement and concrete surfaces reduces the absorption of water into the ground, causing lower water tables and increased runoff into storm sewers and streams, resulting in flooding.

Population growth intensifies these issues as more people rely on finite water sources. The increased demand leads to overexploitation and further strains already limited resources. Additionally, population growth can result in the improper treatment of wastewater, with chemicals, oils, and non-biodegradable materials ending up in water bodies, contributing to pollution.

Fish farming, or aquaculture, while providing a source of food, can also contribute to water pollution. The high density of fish in enclosed areas produces large amounts of waste, which can contaminate surrounding waters with harmful chemicals and nutrients. Antibiotics and pesticides used in fish farming can also pollute water sources if not properly managed.

Microorganisms and chemical substances

Water pollution is the contamination of bodies of water by the introduction of substances that interfere with the natural functioning of ecosystems and render the water unsafe for human use. Water pollution can be caused by a wide range of chemical and non-chemical substances, as well as microorganisms.

Chemical Substances

Chemical substances are a major contributor to water pollution. These substances can be toxic and have severe ecological and human health impacts. Some common chemical pollutants include:

• Petroleum and oil spills: Oil spills, such as the Deepwater Horizon spill in 2010, can strand and kill marine life, impacting ecosystems and local communities.
• Industrial waste: Wastewater discharge from factories and industrial facilities can contain toxic chemicals, heavy metals, and pollutants like mercury and lead, which are harmful to aquatic life and human health.
• Agricultural runoff: Chemical fertilizers, pesticides, and animal waste from farms can contaminate nearby waterways and groundwater, damaging wildlife and rendering water unsafe.
• Nutrients and fertilizers: Excess nutrients, such as nitrogen and phosphorus, can cause eutrophication, leading to oxygen-deficient "dead zones" where aquatic life cannot survive.
• Toxic chemicals: Various toxic chemicals, including mercury, nitrate compounds, and radioactive substances, can contaminate water, posing risks to both ecosystems and human health.

Microorganisms

Microorganisms, such as bacteria, viruses, and parasites, can also contaminate water and cause significant health issues. These microorganisms are often introduced through human activities and sewage:

• Pathogenic bacteria: Escherichia coli (E. coli), Vibrio cholerae, and Salmonella are examples of bacteria that can cause waterborne infections and gastrointestinal disorders in humans.
• Viruses and parasites: Water can be contaminated by viruses like hepatitis A and E, and parasites such as Giardia and Entamoeba, leading to diseases with symptoms like diarrhea, fever, and body aches.
• Sewage: Domestic sewage is a significant source of microbial pollution, introducing disease-causing microorganisms like fecal streptococci and coliform bacteria into water sources, making them unsafe for drinking and recreation.

Combined Impacts

The introduction of chemical substances and microorganisms into bodies of water can have cumulative and synergistic effects, exacerbating the impacts on ecosystems and human health. For example, the presence of certain chemicals can promote the growth of harmful algae, which, upon decomposition, depletes oxygen levels in the water, creating "dead zones." Additionally, the presence of microorganisms in water can indicate the presence of other, more harmful contaminants, as they often share similar sources of introduction, such as sewage and wastewater.

Frequently asked questions