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What are the pollutants in water

Water is an essential element for the life of living beings. Many of the human activities need water such as industry, agriculture, livestock and households. At the same time, these activities reduce the amount of water available for consumption and especially its quality. There are thousands of substances that pollute the water and endanger aquatic ecosystems and the survival of many species.

If you want to know more about which are the polluting agents in water , in AgroCorrn we are going to explain the most important ones.

You may also be interested in: What are the soil pollutants
  1. List of the main water pollutants
  2. Wastewater that pollutes water and soil
  3. Heavy metals, one of the worst pollutants in water
  4. Radioactivity in water: a deadly water pollutant
  5. Pesticides that pollute water
  6. Hydrocarbons
  7. Pathogenic microorganisms
  8. Emerging or new water pollutants

List of the main water pollutants

To begin, as an outline or summary, we give a list of the main water pollutants , both groundwater and surface water , both fresh and salt water.

  • Sewage water.
  • Heavy metals.
  • Radioactivity
  • Pesticides
  • Hydrocarbons.
  • Pathogenic microorganisms.
  • Emerging pollutants.

In the following lines, we talk in detail about each of these types of aquatic pollutants .

Wastewater that pollutes water and soil

Most human activities generate wastewater that cannot be returned to aquatic ecosystems without first treating it. These waters can have from abundant amounts of organic matter, oils or fats to very toxic and harmful substances for the environment such as heavy metals or chemicals from industry.

Although normally, wastewater is collected to water treatment plants, in many cases the treatments are not enough. In other cases, populations and industries dump wastewater directly into rivers or other aquatic ecosystems either because they do not have treatment plants, or because it is cheaper to dispose of waste without treating it, or because of possible spills or leaks.

One of the most important consequences is the eutrophication of the waters due to the increase in nutrients, especially nitrogen and phosphorus (detergents, for example) and the amount of organic matter.

Heavy metals, one of the worst pollutants in water

Its presence is closely related to industry and mining. Within the contamination with heavy metals are metals such as chromium, copper, cadmium, mercury, lead and silver; and metalloids such as arsenic or selenium. Its existence in water can endanger human health and that of other living beings due to its extreme toxicity. They can have neurotoxic, mutagenic, teratogenic effects and, in addition, can induce cancer and congenital defects, among other results.

To learn more about this topic, we recommend reading this other AgroCorrn article in which we talk about How heavy metal pollution occurs in water .

Radioactivity in water: a deadly water pollutant

It is mainly due to leaks or accidents in nuclear plants or nuclear power plants , or by the intentional disposal of radioactive waste , referring to uncontrolled waste in nature, not to nuclear cemeteries in which, in principle, it is controlled.

It is a rare type of contamination but very dangerous if it happens, as it is extremely difficult to contain and repair the damage caused.

It must be taken into account that the harmful effects of this pollutant will depend on several factors such as the dose or quantity of radioactive material, the sensitivity of each person or animal, as well as the exposure to this material, both in distance and in greater or lesser protection. .

It can produce from acute and less serious effects, such as general malaise, vomiting, diarrhea, hair loss and skin burns, to being the culprit of serious and long-term or chronic health problems, such as fetal malformations, different types of cancer ( especially thyroid cancer and leukemia), lesions that do not heal or sores, produce abortions due to intoxication of the mother and fetus, among many other effects, as it produces changes in the structure of cells exposed to contamination.

However, it is important to note that the dose and type of exposure are key , because although these are the negative effects of a large exposure or quantity, it is true that radioactivity is present in our environment in different ways, it is used as a treatment for cancer (radiotherapy) and is also used in x-rays, which is very common.

In addition, here we relate it to being a water pollutant, but if there is an accident or spill it becomes a pollutant of the entire environment in a more or less specific area.

Pesticides that pollute water

Pesticides include a wide range of insecticides, herbicides, and fungicides . They are typically used in agriculture to combat insect pests, but they are also used on farms and on domestic animals to prevent infections and other diseases. These substances can reach rivers, lakes and groundwater by leaching, by surface runoff, especially after raining or by infiltration into the ground. Many of these pesticides have been banned due to their dangerous effects on human health such as organochlorine and organophosphate insecticides (eg DDT).

While others have been developed to prori could be less harmful to health and ecosystems for its specificity (pyrethroids, neonicotinoids ), the truth is that many of its effects are yet to be discovered. In the same way, they could be toxic and damage the health of aquatic ecosystems and living beings, including humans.


Hydrocarbons such as gasoline, diesel or oil, among others, are very polluting. They can reach ecosystems through spills , such as the one that occurred in Galicia in 2002 when an oil tanker (El Prestige ) sank off the coast releasing tons of oil; thus these spills, accidental or not, become natural disasters caused by man . On the other hand, when it rains, the water cleans the streets and highways and, therefore, can wash the hydrocarbon stains that may be in them into rivers, lakes, wetlands and groundwater.

Depending on the type of hydrocarbon (volatile, light or heavy), it can be more or less difficult to eliminate, but the consequences for the environment are very harmful and ecosystems take a long time to recover, in many cases exceeding ten years. They can have different toxic effects on organisms depending on the type and amount of hydrocarbon and can even die from suffocation in the case of oil slicks, but it is not only the damage to organisms, many habitats are also destroyed and can even affect the socio-economic activities in the affected areas.

Pathogenic microorganisms

In water, many microorganisms also exist naturally, which may or may not be toxic to humans.

However, activities such as intensive livestock farming or contamination by sewage can increase the number of pathogenic microorganisms in the water , such as coliform bacteria and Enterobacteriaceae. Its presence in the water indicates that there has been contamination by animal and human feces and / or waste . The consumption of water contaminated with these types of organisms can lead to serious health problems such as diarrhea, infections and even death, as occurs, unfortunately, in many underdeveloped countries.

Emerging or new water pollutants

Emerging pollutants are those pollutants unknown so far or not recognized as such. The presence in the environment of emerging pollutants, in many cases is not new, but they are found at such low concentrations that in the past they were not possible to detect. Currently, with the development of new analytical techniques and methods, it is possible to detect and quantify them in the medium.

Emerging pollutants include everyday products. Here are some examples of emerging pollutants :

  • Drugs (ibuprofen, paracetamol, antibiotics).
  • Perfluorinated compounds (non-stick pans, food wrapping papers, cleaning products, fire fighting foams).
  • Hormones
  • Drugs of abuse.
  • Personal care and hygiene products.
  • Nanoparticles and microplastics have recently been added to this list.


NanoparticlesThey are microscopic, on the order of one billionth of a meter, and usually measure between 1 and 100 nanometers. Currently, these are produced from different materials and with different purposes. They can be found in sportswear in order to prevent bad odors from permeating fabrics, in creams or sunscreen, in the construction industry, as well as in the automotive industry or they also have great potential to become a vehicle for serve to transport drugs that improve the effectiveness of treatment. Nanoparticles can be of natural origin (organic matter or volcanic materials), they can come from human activity (diesel or smoke emissions) or they could have been specially manufactured such as carbon nanomaterials (fullerenes, nanotubes) or metallic ones (nanoparticles of gold, silver, metallic oxides). The latter have increased considerably in recent years and have even been found in domestic wastewater.


Finally, microplastics , either those that come from the degradation of other plastics or that are manufactured in this way (glitter, particles in cosmetics, etc.) are those that are less than 1 mm in size. They have been detected in both marine and freshwater ecosystems. They can affect the endocrine system of fish, they can obstruct the respiratory tract and digestive systems of many animals, they can cause wounds and infections, and they also accumulate pollutants that are present in the environment, aggravating the problem of the existence of plastics in the environment .

Here we explain more about what microplastics are: definition and types .

If you want to read more articles similar to What are the pollutants in water , we recommend that you enter our Pollution category .

Maria Anderson

Hello, I am a blogger specialized in environmental, health and scientific dissemination issues in general. The best way to define myself as a blogger is by reading my texts, so I encourage you to do so. Above all, if you are interested in staying up to date and reflecting on these issues, both on a practical and informative level.

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