Generally, rivers are the main source of life because they provide freshwater, which is critical for the survival of both flora and fauna. The uniqueness of rivers is that they provide homes to fish, reptiles, mammals, and amphibians. For this reason, the conservation of rivers is needed since the cycle of the ecosystem is dependent on them. However, there has been massive global pollution of rivers, thereby causing a shift in the ecosystem. This has been caused by the increased pressure on the bodies of water and the rapid increase in the human population.
Moreover, the releases of toxic waste from industries, urban centers, and agricultural pollution have saturated rivers with pollutants, resulting in serious water problems such as the lack of clean drinking water. To get an idea of how expansive rivers are polluted, this article presents a list of the top 21 most polluted rivers in the world as of 2020.
- 1. Ganges River
- 2. Yellow River
- 3. Doce River
- 4. Citarum River
- 5. Mississippi River
- 6. Sarno River
- 7. Marilao River
- 8. Buringanga River
- 9. Mantaza-Riachuelo River
- 10. Tijuana River
- 11. Jordan River
- 12. Yangtze River
- 13. Yamuna River
- 14. River Nile
- 15. Murray-Darling River
- 16. Indus River
- 17. Passaic River
- 18. River Danube
- 19. River Plate
- 20. River Salween
- 21. Rio Grande
1. Ganges River
The Ganges is the most sacred river in India. The Hindus believe that the river cleanses people from their sins. It is the third-largest river in the world, with a consumption base of over two billion people. The river’s ever-increasing pressure has resulted in the dumping of raw sewage into it, leading to its massive pollution.
Due to the combination of chemicals in the river, water used for basic uses such as drinking or cooking leads to the spread of waterborne diseases. The river has a layer of floating plastic and other waste which provides a poor image of the holy river. Besides, there are waste products that also come from the performance of religious rituals.
2. Yellow River
China has the fastest-growing economy, and this is attributed to its rapid industrialization. The Yellow River has yellow sediment ‘loess’ which attributes to its yellow colour.
This river is home to industrial waste from various industries, including chemical factories, rendering the water too toxic even for agriculture. More specifically, the coal mining industry releases a lot of waste back into the river after using water from it to run its operations.
Nevertheless, people are still dependent on the river for drinking water. It is because of this that the area around the river has seen a rise in the occurrence of waterborne diseases, cancers and birth defects. Most recently, there have been efforts to dissuade people from drinking the water from this river since it is unsafe for human or animal consumption.
3. Doce River
The Doce river runs through the southeastern part of Brazil for 853 kilometers. This river was once a great source of fresh water and was used by industries for steel making. However, in November 2015, the river was contaminated by 60 million cubic meters of iron ore sludge from two containment dams that ruptured.
The heavy metals from the sludge that contaminated the river killed a lot of aquatic life in the river, and just directly made the river not useful for any human consumption and uses. Experts state that it will be very difficult for the river to recover from the ecological catastrophe that happened, making the river one of the most polluted river in the world.
4. Citarum River
The Citarum is arguably one of the most polluted rivers in the world. Like the Ganges, it serves a big population. Indonesia, the home of the Citarum, may not be as populous as India or China, but it is still in the top league with a population of over 200 million. The river flows in an area where there are heavy human settlements coupled with a number of factories.
The industrial waste from 2,000 factories has led to an increase in the mercury levels of the water far above the legislated and original level. The river is dirty and polluted from the source all the way to the outlets.
Unfortunately, both entities use the Citarum as a dumping site, rendering it polluted. Since the river serves a large population, the residents are forced to use the water source despite its state. However, the river has continually robbed the country of people, with over 50,000 deaths annually.
5. Mississippi River
The Mississippi river is one of the longest rivers in the world. As such, it serves millions of US residents. The river is brown in color, owing to the constant release of waste into the river. The marine life in the river has reduced alarmingly due to various oil spillages in the past. More waste comes from industries and farmers who use harmful chemicals and release them into the river.
The river has a high level of nitrogen-based fertilizer run-off, which instead of leaching in the soil, upsets the food chain and reduces the oxygen levels in the water, thus causing the death of aquatic life. The major pollutants are benzene, mercury, and arsenic.
6. Sarno River
This is arguably the most polluted river on the European continent. The river that flows through Italy has, over time, become a poison to the residents. The source of the river is clean and safe for drinking. Nonetheless, its flow is faced with releases from industries and agriculture, leading to a polluted river downstream.
The toxicity of the river has caused an alarming increase in liver cancer cases in the area. What is more, the river easily floods, leading to mudslides and toxicity on earth. Poor waste treatment control has led to the increased pollution of the Sarno.
7. Marilao River
This river is home to millions of Philippine residents who use the water for drinking and also for irrigation. The pollution of the river is mostly from waste from tanneries, dumping and gold refineries. The dumping of non-recyclable materials such as plastic bottles is present on the surface of the water. In addition to this, the water contains rocks bearing heavy metals, which pose a health hazard to the residents.
The river, like the Sarno, is prone to flooding, which brings the waste to the land, thus leading to soil degradation. The pollution of the water is detrimental to the fish industries in the Philippines since toxic metals such as lead contribute to the death of aquaculture.
8. Buringanga River
This river is a source of life for millions of Bangladesh residents. It is also a major economic resource for the country since it is the biggest river in the country. The river is mainly polluted by the tanneries that border it. There has also been a lot of human waste in the river.
There is a lot of floating waste material in the river, such as plastic and dead animals. This has contaminated the water and rendered the discharge so intense that the river has turned black. Consequently, the aquatic life of the river has since died.
9. Mantaza-Riachuelo River
The river is based in Argentina and is arguably the most polluted river in South America. The presence of industries around the river has not made any cleaning easier. The reason for this is that there are millions of tons of sewage released into the river on a daily basis.
Also, there are heavy metals in the river, such as mercury and lead, which lead to high cases of cancer. These have come into existence due to the release of chemicals from chemical industries. Further, the river, also known as the Slaughterhouse River, is home to waste from slaughterhouses and tanneries, which are rampant along the river. Due to this, the river has a foul smell.
10. Tijuana River
The Tijuana River flows north through the Tijuana River Valley, passing through Tijuana, Mexico. This river runs 120 miles, and at times carries only a little water. The river is quite contaminated and polluted due to the millions of US gallons of sewage being dumped into it every year.
Some of the toxic chemicals that are present in this river are DDT, benzene, lead, mercury, and hexavalent chromium. Together with tons of tires and trash, the river causes a lot of diseases along its path due to its extreme pollution, especially when the river dries up and the toxicity in the riverbed goes airborne.
Due to the enormous amount of waste and toxic chemicals present in the Tijuana river, it has been considered as one of the most polluted rivers in the world, even if the government of Mexico has already allotted funds in order to clean the river over the years.
11. Jordan River
The source of the river is clean and fit for human consumption. However, as the river flows, it increases in toxicity due to the many waste disposals. This has caused an increase in the salinity of the water. Most of the pollution comes from the refugee crisis in the country, coupled with the increase in the population, both local and international.
12. Yangtze River
Like the Yellow River, the Yangtze River is also found in China. The rapid industrialization in the country has had its toll on the river, which receives a lot of the released water. As a result, there has been a growth in algae through eutrophication. There are many negative effects of this, including the death of aquatic life since there is a minimal source of oxygen in the water.
13. Yamuna River
This is the second most polluted river in India after the Ganges. It boasts its source as the Himalayas, but the river gets more polluted as it moves. The major issue is the poor management of raw sewage by the Indian government. There are few functional sewage plants in the city of New Delhi, which dampens the glory of the big capital city.
Further, agricultural and industrial waste have also played a role in the pollution of the Yamuna. The river has been polluted so much that the establishment of water treatment might not reduce the level of toxicity in the river. More to this, unlike normal water with a pH level of 7, the pH level of the Yamuna is 11. This has been caused by traces of poison in the water, which has raised the pH.
14. River Nile
In Egypt, when the most common diseases are reported to be bacterial diarrhea, typhoid fever, and schistosomiasis, all of which have a connection to unsafe water and poor sanitation, then it is clear that the focus must shift towards one source: the Nile.
Egypt is the most populous, agricultural, and industrial country in the basin. Therefore, most sewage releases into the river take place in Lower Egypt. Nile pollutants are derived from sources such as industrial wastewater, oil pollution, municipal wastewater, and agricultural drainage, and include natural cyanotoxins.
Besides excessive water extraction from the River Nile for irrigation, growing saltwater incursion in coastal areas and the decline in the availability of fresh water in the delta region have created huge problems for species living in its waters.
15. Murray-Darling River
The health of the River Murray is critical to the current and future wellbeing of South Australia. In the River Murray, the main water quality problems relate to water management and the need to maintain sufficient water levels in the main channel to limit saline inflows upstream and problems associated with Lower Murray Irrigated Reclaimed Area (LMRIA) discharges in the lower weir pool (downstream of Mannum).
The other sources of pollution of concern to the EPA include:
- Septic leakage from housing adjacent to the river and floodplain areas.
- Contaminated stormwater run-off from developed land areas.
- Sand dumping from creating beaches (often associated with vegetation removal).
- Managing black and grey water from vessels.
Autochthonous species in the river, one of the most important in Australia, have plunged to 10% of their levels prior to European settlement. On the other hand, invasive species have significantly jumped in number, causing an imbalance in its biodiversity that has left nine native species in danger of extinction, affecting aquatic flora and water quality.
16. Indus River
Pakistan’s main river is in grave danger as it is highly polluted as a result of litter, untreated agricultural, industrial, and municipal waste.
At a recent seminar organized by the Environmental Protection Agency (EPA), Sindh, it was informed that the Indus river is highly polluted. The levels of various parameters are high enough to classify the river as polluted. Even the coliform level, which should not have been present in water bodies at all, averaged 800 per 100 ml.
Added to this, the constant extraction of water for farming activities and the incursion of saltwater into the delta are wiping out part of its natural biota.
17. Passaic River
It is 80 miles long in New Jersey. The source is the Mendham, and the mouth is Newark Bay. The Lower Passaic has borne a heavy burden of pollution from a century of industrialization in the Passaic River Watershed.
The manufacturing industries have left behind layers of dioxin, mercury, PCBs, and many other harmful contaminants in the sediment. This pollution, along with harmful disease-causing organisms brought in through combined sewer overflow events, has worsened the river’s water quality.
18. River Danube
A wide-ranging global study has identified the Danube as the river with the highest concentration of antibiotics in Europe and the single most polluted on the continent. Chemical waste is its great enemy, and it is not just farming pesticides but waste from Serb factories bombarded as of 1999.
According to a study, the Danube is the most contaminated river in Europe with antibiotics. After taking samples from a Danubian site in Austria, researchers found traces of up to seven antibiotics, surpassing the safety threshold.
Another factor in the river’s growing contamination is increasing river traffic.
19. River Plate
The River Plate is the second biggest watercourse in South America. Tipping of industrial waste and waste disposal by neighborhood communities is an incessant source of pollution in this river. In recent years, the sluicing of the water with chemical waste from farming activities has also increased, including it in the list of most polluted rivers on the planet.
20. River Salween
Located in South-East Asia, the Salween, born in Tibet, meanders down through regions of China and Burma. The Salween is considered the most polluted river on the planet, so much so that some fishing communities have abandoned their former trade to sell the glass and plastic they collect from the river.
Over its course, it passes through industrial parks, mostly made up of textile factories, whose polluting waste has provoked an alarming increase in sulfur, cadmium, copper, lead, mercury, and zinc levels in the river.
21. Rio Grande
The Río Grande is the second biggest watercourse in the United States. Two decades ago, many Mexican border communities treated little or no wastewater and instead dumped it into the Rio Grande. Its basin is increasingly polluted by the tipping industrial waste.
Perez’s town is one of many along the Texas-Mexico border where water supplies are threatened by persistent pollution in the Rio Grande, due, in part, to raw sewage coming from Nuevo Laredo in Mexico.
Perez, local officials and environmental advocates along the border are calling for the US and Mexico to tackle the problem of Rio Grande pollution more aggressively.