Water Pollution's Worst Offenders: Where Is It Highest?

Water pollution is a pressing issue that affects countries worldwide. Globally, demand for water has more than doubled since 1960, and with it, the vulnerability of our water sources to pollution. Water pollution arises from various sources, including toxic substances from farms, towns, factories, sewage, and oil spills. While water pollution is a global issue, certain regions experience higher levels of water stress and pollution than others. This introduction will explore the varying levels of water pollution across the world and the factors contributing to this critical issue.

Oil pollution in the seas

Water pollution is a pressing issue globally, with agriculture being the leading cause of water degradation. However, oil pollution in the seas is a significant concern, and it is important to understand its sources and impacts.

The impacts of oil pollution in the seas can be devastating for the environment and wildlife. Major spills have coated shorelines and killed or harmed numerous animals, including seabirds, marine mammals, and fish. Oil pollution can also have more subtle biological effects due to the toxicity of the compounds in petroleum, which can persist over time. The compounds formed during the degradation of petroleum can also be toxic, further exacerbating the problem.

Efforts to address oil pollution in the seas have been made through international conventions and regulations, such as the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78), which has helped reduce the number of oil tanker disasters. Additionally, the International Maritime Organization (IMO) adopted the International Safety Management Code (ISM Code) to ensure the safe operation of vessels and prevent environmental damage.

Despite these efforts, there is still a lack of well-coordinated contingency plans for responding to major oil spills. The clean-up process can be challenging and costly, as seen in the case of the decommissioned Hanford nuclear site in Washington, where the clean-up of radioactive waste is expected to cost over $100 billion.

Overall, oil pollution in the seas is a complex issue that requires continued scientific, regulatory, and technological advancements to mitigate its impacts and protect the marine environment.

Radioactive waste

Anthropogenic sources of radioactive pollution include nuclear weapon investigations, nuclear power plants, nuclear calamities, and the dumping of radioactive waste. The application of radioisotopes in industries and scientific laboratories are minor sources. The use of radioactive elements in nuclear weapons, X-rays, and medical equipment like MRI machines causes exposure to humans. The dumping of radioactive waste in surface water bodies also causes water pollution. Uranium, thorium, and actinium are three NORM series that contaminate water resources. Radium, a descendant of the NORM series, is one of the most radiotoxic elements found in aquatic systems. It can penetrate groundwater through aquifer rock dissolution, the decaying of uranium and thorium, or desorption processes.

Nuclear reactors and nuclear warhead experiments are the key sources of human-induced radionuclide discharge. Nuclear reactors produce radioisotopes like Cobalt-60 and Iridium-192, which are used as sources of gamma radiation in radiotherapy and industrial appliances. Additionally, they create unnecessary radioactive waste, such as Strontium-90 and Caesium-137. Mining activities for radioactive elements like uranium and thorium also pollute surface and groundwater.

One of the most polluted spots on Earth is Lake Karachay in eastern Russia, which was used as a dumping ground by the Soviet Union's Mayak nuclear weapons laboratory and fuel reprocessing plant. A string of accidents and the drying out of the lake in the 1960s led to the contamination of the surrounding area and the irradiation of hundreds of thousands of people. The Techa River, which provides water to nearby areas, was also contaminated, resulting in radiation sickness in about 65% of local residents.

Water pollution in Africa

One of the primary causes of water pollution in Africa is plastic waste. Thousands of tons of plastic waste are shipped to African countries from the Global North each year, ending up in fragile river and dam ecosystems. This plastic pollution has severe impacts on marine life, with many sea animals mistaking microplastics for food and choking to death. It also affects human communities, as plastic waste blocks drainage systems, leading to dangerous flooding during the rainy seasons.

Agricultural runoff, industrial activities, and domestic wastewater disposal are other significant sources of water pollution in Africa. Rivers, lakes, and groundwater are contaminated by chemicals, heavy metals, pathogens, and other pollutants. In Kenya, for example, the Nairobi River, once a vibrant waterway in the country's capital, has become a conduit for untreated sewage, agricultural runoff, and plastic waste, making its water unsafe for human or animal consumption. Similarly, Lake Victoria and Lake Nakuru in Kenya are being choked by agricultural contaminants, raw sewage, plastic, and nutrient-dense fish waste.

Water pollution has dire environmental consequences, devastating aquatic habitats and contributing to biodiversity loss. It creates dead zones in aquatic habitats where oxygen levels are too low to support life, leading to a concerning decline in biodiversity. Water pollution also exacerbates water scarcity, with one in three people in Africa affected by water scarcity.

The impacts of water pollution extend to public health, particularly affecting vulnerable populations. Contaminated water sources breed waterborne diseases like cholera, dysentery, and typhoid, posing significant health risks. In sub-Saharan Africa, 115 people die every hour from diseases linked to contaminated water, improper hygiene, and poor sanitation. Waterborne illnesses also lead to malnutrition and stunted growth in children and divert healthcare resources from other pressing health concerns.

The world's most polluted rivers

Water is a "universal solvent", able to dissolve more substances than any other liquid on Earth. This makes water especially vulnerable to pollution. Toxic substances from farms, towns, and factories readily dissolve into and mix with it, causing water pollution.

Agriculture is the leading cause of water degradation worldwide. In the United States, agricultural pollution is the top source of contamination in rivers and streams. Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens—such as bacteria and viruses—into our waterways.

The Citarum River, Indonesia

The Citarum River is one of the most polluted rivers in the world. The river serves a large population, with Indonesia's population exceeding 200 million residents. The river flows through an area with heavy human settlements coupled with numerous factories. The industrial waste from these factories has led to an increase in the mercury levels of the water, far above the accepted standard. The river has been deemed responsible for over 50,000 deaths annually.

The Ganges River, India

The Ganges River is the third-largest river in the world, with a consumption base of over two billion people. The Hindus consider the river sacred, believing that it cleanses people of their sins. However, the river is a victim of massive water pollution due to the dumping of raw sewage and chemicals. Communities frequently exposed to the river have reported higher incidences of waterborne diseases, and the river is now covered with a layer of floating plastics.

The Sarno River, Bangladesh

The Sarno River is a source of life for millions of Bangladesh residents and is a major economic resource for the country. While its source is clean and safe for drinking, poor waste treatment control has led to increased pollution. The unchecked dumping of agricultural, human, and industrial waste has contaminated the river, leading to frequent flooding and soil degradation.

The Mississippi River, USA

The Mississippi River is one of the most polluted rivers in the United States. A "Dead Zone" has been created by unchecked industrial waste, sewage, and agricultural runoff. The river remains crucial for commercial and recreational activities and is the source of drinking water for more than 18 million Americans.

Unnamed River, Philippines

This unnamed river in the Philippines is home to millions of residents who use the water for drinking and irrigation. The river has turned black, and the aquatic life in it has died. The river is mainly polluted by the tanneries that border it, as well as human waste, plastics, and animal carcasses. The dumping of non-recyclable materials, such as plastic bottles, can be seen on the surface of the water. The river is also prone to flooding, which brings wastes to the land, causing soil degradation and negatively impacting the local fish industries.

Agricultural pollution

Water is a "universal solvent", meaning it can dissolve more substances than any other liquid on Earth. This makes water especially vulnerable to pollution. Water pollution is caused by a variety of factors, including industrial, urban, and agricultural waste.

Agriculture is the leading cause of water degradation worldwide. In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It is also a major contributor to the contamination of estuaries and groundwater.

The National Water Quality Assessment in the US shows that agricultural runoff is the leading cause of water quality impacts on rivers and streams. About half a million tons of pesticides, 12 million tons of nitrogen, and 4 million tons of phosphorus fertilizer are applied annually to crops in the continental United States. Soil erosion, nutrient loss, bacteria from livestock manure, and pesticides are primary stressors to water quality. These contaminants are moved into local streams, rivers, and groundwater through runoff, infiltration, and irrigation return flows.

Agricultural conservation practices can help to minimize the impact of agricultural pollution on water quality. For example, drip irrigation instead of furrow irrigation decreases water loss and allows better control of the amounts of pesticides and nutrients added to irrigation water. Storing livestock manure in covered stockpiles or protected upland areas minimizes runoff risks. Additionally, contour strip cropping reduces erosion and runoff.

In addition to the environmental impacts, agricultural pollution also affects human health. Rural residents may be exposed to contaminated water, air, and food. Pesticides can be harmful to both humans and pollinators, such as bees and butterflies. Livestock production also contributes to greenhouse gas emissions and climate change.

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