The contamination of the rivers It is the introduction into its channel of foreign substances or organisms that affect the quality of its waters. As a consequence of this, there is a negative impact on the associated ecosystems.
One of the main causes of river pollution is untreated urban or industrial water. Another important source of pollutants is solid waste dumped or washed into the river.
On the other hand, agricultural and livestock activities generate waste that is carried by groundwater or surface runoff to rivers. These substances include fertilizers and pesticides. Likewise, mining activity and oil exploitation are a source of river pollution, causing heavy metal and hydrocarbon spills..
Among the most common contaminants are organic substances such as food waste and feces, and inorganic substances such as chemicals, plastics and heavy metals. Likewise, contamination can occur due to the introduction of exotic species or pathogenic microorganisms to the river..
Among the main consequences of river pollution is the loss of water quality, making it undrinkable. Similarly, it affects biodiversity that is threatened by toxic substances or eutrophication processes. River pollution also affects economic activities such as tourism and agriculture. In the latter case as a consequence of the poor quality of the water for irrigation.
Most of the world's rivers present some degree of contamination, particularly those that cross large urban centers. There are extreme cases where the levels of contamination, both by toxic substances and solid waste, exceed any limit. For example, the Citarum River on the island of Java (Indonesia), is considered the most polluted in the world and the plastic waste present does not allow us to see the channel.
Some rivers, like the Bogotá in Colombia, have entire stretches that are considered biologically dead. Other cases such as Murray-Darling, the problem is the introduction of exotic species (carp) that affects local species..
On the other hand, river pollution impacts the oceans, as is the case in the dead zone in the Gulf of Mexico. This is due to eutrophication caused by the contribution of chemical nutrients resulting from the pollutant load of the Mississippi River..
In Latin America, the case of Mexico stands out, where 35 of its 51 main rivers present serious pollution problems. In Colombia, in addition to the aforementioned Bogotá river, others such as the Magdalena and the Cauca are also severely affected.
In the case of Venezuela, all the rivers of the Caribbean basin and the endorheic basin of Lake Valencia are seriously polluted. As for Peru, 35 rivers present serious problems of contamination by heavy metals.
In order to avoid the contamination of rivers, it is necessary to properly treat sewage and carry out an adequate management of solid waste. In addition, sustainable agriculture must be promoted and strict legislation must be established to protect rivers..
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The main cause of contamination of rivers is the discharge into their waters of effluents, coming from urban and industrial centers. These discharges can come both from the sewage system and carried superficially by runoff water due to the rains..
Another source of contamination of rivers is the discharge of solid waste generated in cities and towns into their channel. One of the most serious problems is the large amounts of plastic that end up in rivers.
Intensive agriculture makes use of large amounts of chemical fertilizers and pesticides. A high proportion of these agrochemicals are lost by leaching or dragging of runoff water ending up in rivers.
Some of these substances are toxic or carry heavy metals, and the excess of nutrients provided by fertilizers generates eutrophication processes. This phenomenon involves the uncontrolled growth of algae and bacteria that consume dissolved oxygen, affecting the biodiversity of the river..
Pig and poultry farms are among the most polluting, especially due to untreated effluents that carry fecal matter. Various pathogens can pollute river water with serious consequences for wildlife and human health.
Oil extraction generates so-called heavy metal-rich extraction sludge, as well as oil spills, just like in the transportation process. All these wastes can end up in rivers causing serious ecological problems.
On the other hand, mining uses destructive methods of the soil generating the transport of sediments, heavy metals and other components to the rivers. In some cases, highly toxic substances are used to separate the metal, such as mercury in gold mining..
Industries emit gases such as nitrogen dioxide (NO2), nitrous oxide (NO), sulfur oxide or sulfur dioxide (SO2) and carbon dioxide (CO2) into the environment. These gases are precursors of the formation in the troposphere of nitric acid, sulfuric acid and carbonic acid that then precipitate with rainwater..
Acid rain acidifies rivers and contributes to the eutrophication process, seriously affecting aquatic life and the potability of water.
The introduction of exotic species (not typical of a particular ecosystem) in rivers can cause serious ecological imbalances. An example is the introduction of carp in the Murray-Darling basin (Australia), affecting native species that are in danger of extinction..
Organic waste that reaches rivers through untreated urban effluents includes fecal matter and food debris. This type of waste is especially dangerous because it provides pathogenic microorganisms that cause various diseases..
Among the diseases associated with contaminated water are diarrhea, hepatitis, typhoid fever and cholera. One of the water pollution indicators is the presence and level of total coliforms (bacteria such as Escherichia coli and others).
Soaps and surfactants used in the home and industry can reach rivers through untreated sewage. Detergents are very polluting, since they directly affect cell membranes by breaking their surface tension.
These substances, both of domestic and industrial origin, are dangerous pollutants because they are not diluted in water. For this reason, they form superficial films that prevent the exchange of oxygen from the water with the atmosphere, causing the death of aquatic life by suffocation..
Industries incorporate all kinds of waste chemicals into their drainage systems and if these effluents are not properly treated, they affect rivers. Among the most common pollutants are heavy metals such as mercury, cadmium, lead, arsenic, nickel and chromium.
Waste from the pharmaceutical industry, in some cases, is a cause of significant contamination as has been determined in the Ebro river (Spain).
Of the solid waste that ends up in rivers, the most problematic are plastics due to their abundance and slow rate of degradation. Most of the solid waste present in these water sources is plastic containers and bags..
Chemical fertilizers are the main cause of eutrophication due to the supply of excess nutrients. These fertilizers can provide macronutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. They are also a source of micronutrients such as iron, copper, manganese, zinc, boron, molybdenum and chlorine..
In modern agriculture and animal production, a large number of herbicides, insecticides and dewormers are used that can end up being washed into rivers.
Many drugs used in livestock, poultry production and aquaculture end up polluting waterways.
The main consequence of the contamination of rivers is the loss of the quality of the water they transport, which reduces the sources of drinking water.
The contamination of rivers, in extreme cases can cause the death of the biodiversity it presents due to various factors. In turn, the death of aquatic life affects the entire food chain of terrestrial ecosystems linked to the river.
Many rivers are the object of tourist activity so they provide benefits in terms of recreation and economics. The contamination of these areas diminishes their tourist attraction and, in extreme cases, cancels it.
River pollution can cause serious health problems for the communities that depend on them. Polluted rivers become a source of pathogenic microorganisms that cause diseases and their waters can cause skin problems.
The consumption of water contaminated by heavy metals such as mercury, lead or arsenic causes serious poisoning. Among some pathologies that can cause stand out the alterations of the nervous system, endocrine imbalances and kidney diseases.
Rivers are bodies of water that flow and their waters end up flowing into lakes or oceans. In this sense, the pollutants they carry, such as plastics, end up directly affecting the world's lakes and oceans..
It is located to the west of the island of Java (Indonesia) and is considered the most polluted on the planet. This river supplies 80% of the water of the capital Jakarta and is used as a means of transport and for agricultural irrigation.
Its main source of pollution is sewage and solid waste from 9 million people and hundreds of factories.
It is born in eastern Tibet, passes through the Yunnan province in China, passes between Burma and Thailand and ends up emptying into the Andaman Sea. It is considered the second most polluted river in the world and aquatic life has largely disappeared from its course.
This river receives the untreated effluents and solid waste from a large number of towns and urban centers.
It is a river in northern India that originates in the Himalayas and is a tributary of the Ganges River. Its waters are used for agricultural irrigation and 57 million people depend on them..
It receives the sewage from Delhi through 15 collectors that generate contamination mainly by fecal coliforms. Moreover, it receives pesticide and fertilizer waste from runoff from agricultural land.
It is born in the Himalayas, runs between India and Bangladesh and is divided into two large branches that are the Hooghly River and the Padma River. The Ganges is the holiest river for Hindus and one of the most polluted on the planet, affecting 600 million people.
It receives close to one billion liters of untreated wastewater from numerous cities. It is also a recipient of agricultural and industrial pollutants, human and animal remains, as well as numerous religious offerings wrapped in plastic..
They are two rivers that flow through the southern part of Australia, the Darling being a tributary of the Murray, forming one of the largest river basins in the world. This basin is affected by pathogens, organic matter, heavy metals and toxic chemicals mainly from agriculture..
Its main problem is biological contamination with the introduction of exotic species, including carp. Nine of the 35 native varieties of fish have been officially declared in danger and ten of them are in critical situation.
It is born in the Tibetan plateau, crosses China, India and Pakistan and empties into the Arabian Sea. It is affected by industrial pollution from untreated effluents and the construction of dams that have decreased its flow and concentrated pollutants..
It is born in the Himalayas and crosses China, Burma, Laos, Thailand, Cambodia and Vietnam. It is recognized as the river with the most fishing resources in the world with 2,600,000 tons of fish annually.
The main pollutants that affect it are arsenic, mercury, ammonia and feces, due to untreated effluents and agricultural and industrial residues..
This river of great historical importance is the second longest in the world. It is born in Burundi and crosses ten countries until reaching Egypt where it empties into the Mediterranean Sea..
Its main problem is the almost 300 million tons of polluting discharges that are thrown annually by the urban centers and agricultural areas that it crosses. This includes feces, solid waste, dead animals, and even hospital waste..
It is a river in China, a tributary of the Yangtze, which rises in the Haiyang Mountains and flows through the province of Hunan. Its pollutants are mainly heavy metals that come from industrial areas, since it runs through one of the most industrialized regions of China.
In turn, zinc and lead mining activity also represents a source of contamination to the river, especially with antimony (a by-product of zinc mining).
Located in China, it is the largest river on the Asian continent and the third longest on the planet. In it, 40% of the country's waste is discharged, which corresponds to about 25 billion tons per year.
The main sources of pollution are agricultural waste, effluents from cities and industries, as well as river navigation.
It is located in the north of the Philippines, running from Laguna de Bay to Manila Bay, through the capital Manila. Its main problem is urban and industrial effluents and solid waste, especially plastic.
Its state of contamination is so serious that by 1990 it was established that the river was biologically dead.
Located in West Java (Indonesia), this river is totally covered in solid waste, especially plastic. It is estimated that hundreds of tons of garbage enter the river daily and most of it ends up in the sea.
This river is located to the east of Argentina, and is called Matanza in most of its channel and Riachuelo near the mouth of the Río de La Plata. It is considered the most polluted riverbed in South America due to the 88,000 cubic meters of sewage waste that it receives daily..
Among the river's pollutants are mercury, zinc, lead, chromium, dioxins, furans, cadmium, nickel, arsenic, selenium, and benzenes. In some cases, these elements are found in concentrations greater than 50 times what is allowed..
This river is born in the páramo de Guacheneque in the department of Cundinamarca (Colombia) and is a tributary of the Magdalena river. It is affected by contaminated discharges from factories from its source to its mouth, especially sewage from the city of Bogotá.
In some of its sections it is considered biologically dead and its main pollutants are organic waste. Also heavy metals such as cadmium, chromium, mercury, zinc, arsenic and lead can be found..
The Danube flows through central Europe through ten countries from Germany to Ukraine emptying into the Black Sea. It is highly polluted by solid waste, industrial effluents and agricultural residues..
The amount of polluting waste it receives daily is estimated at 1,500 tons. On its banks are numerous plastic factories and the geographic area that affects the river includes about 80 million people.
It runs along the border between the US and Mexico, ending in the Gulf of Mexico. It is called the Rio Grande in the United States and the Rio Grande in Mexico. The contamination of this river is fundamentally by agricultural residues and untreated urban sewage..
The problem is aggravated due to the decrease in its flow due to dams and the diversion of water used for irrigation.
It is the longest river in the United States and the fourth in the world. It passes through ten states and empties into the Gulf of Mexico. Around 5,443,104 kilograms of toxic chemicals are discharged into its riverbed.
Most of these toxic products come from fertilizers and pesticides as a consequence of agricultural activities in much of the United States..
Agricultural nutrient discharges from the Mississippi into the Gulf of Mexico have created a serious eutrophication problem. This has generated a hypoxic area (low in oxygen), which covers about 22,720 km2.
It is really an estuary or marginal sea formed by the confluence of the Paraná and Uruguay rivers that runs between Argentina and Uruguay. It flows into the Atlantic Ocean and is considered the widest in the world.
Its greatest source of contamination is in the area of the city of Buenos Aires, especially due to the contribution of the Riachuelo and Reconquista tributaries. Receives sewage water, without adequate treatment, as well as industrial and agricultural waste.
It is a tributary of the Paraná River that is born in the Sierra de Mar in Brazil and crosses the city of Sao Paulo. It has a high degree of contamination as a result of the discharge into its waters of industrial and urban waste, both solid and untreated effluent..
This river is born in Lake Chapala in the state of Jalisco (Mexico) and empties into the Pacific Ocean. On its banks there are about 400 factories that discharge their effluents into the river and receive sewage from the metropolitan area of Guadalajara..
It is considered that about a thousand pollutants including heavy metals and other pollutants enter the river daily, affecting 4.6 million people.
Most of the current pollution of most rivers would be mitigated if four fundamental aspects are addressed, namely:
All sewage of urban and industrial origin must be properly treated before returning it to the rivers. For this, it is necessary to establish treatment plants according to the nature of the waste carried by the waters to be treated..
Solid waste or garbage generated in cities and other populated or industrial centers must be properly processed. It is necessary to establish a system based on the criterion of the three Rs (reduce, reuse and recycle).
Therefore, waste once produced must be properly classified and processed according to its nature..
One of the most difficult problems to face is the agrochemical residues that pollute the rivers. To reduce its impact, it is necessary to reduce and rationalize the use of inorganic fertilizers, as well as pesticides in agriculture..
To minimize the risk of contamination of rivers, it is necessary to establish strict protective legislation and define safety fringes from their banks. The construction of population centers and industries near the banks of rivers is a sure source of pollution.
35 rivers of the 51 main rivers of Mexico have serious pollution problems, especially the Lerma, Bravo and Suchiate rivers. Among the most common pollutants in Mexican rivers are mercury, lead, cadmium, nickel and chromium.
Likewise, arsenic, cyanide, toluene, benzene, chloroform, vinyl chloride, and hormone disruptors such as DEHP are common..
The most common source of river pollution in the country is untreated sewage. In some cases, the source of contamination is mining activity, as in the Sonora River.
The Bogotá river is one of the most polluted in South America, being notable as some sections are considered biologically dead. The main cause of contamination is untreated effluents and poor solid waste management.
Other rivers with serious pollution problems are the Cauca and the Magdalena. In the latter case, mining is also a source of contamination. Pollution by agricultural residues (fertilizers and pesticides) is an important cause of pollution in the Meta river basin.
The main pollution problem of rivers in Venezuela is untreated sewage. This has generated that the rivers that cross populated centers have high levels of contamination, such as the Guaire river that runs through Caracas.
The contamination of all the rivers of the endorheic basin (closed basin) of Lake Valencia have generated a strong contamination of it. On the other hand, rivers such as the Aragua, Güey and Cabriales, which flow into the Lake of Valencia, are literally open-air sewers.
The intense mining activity in the Guayana region is negatively impacting the basins of the Cuyuní, Caroní and Caura rivers, tributaries of the Orinoco River.
The causes of river pollution in Peru are very varied, including untreated sewage, industrial discharges, mining, oil and agriculture. Heavy metals are a relevant problem and more than 22 rivers in the country exceed the permitted levels of cadmium.
In turn, copper contamination is alarming in 35 rivers in this territory. Likewise, according to the National Water Authority (ANA), the Ucayali River, head of the Amazon River, has worrying levels of contamination by fecal coliforms.
In the urban part of Pucallpa, 20,000 fecal coliforms have been recorded for every 100 milliliters of water, when the normal is 2,000 per 100 milliliters of water.
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