Pollution of fresh and salt waters

Pollution of fresh and salt waters

Globally, it is estimated that 80% of industrial and municipal wastewater is discharged into the environment without any prior treatment, causing adverse effects on human health and ecosystems. This proportion is higher in least developed countries, where sanitation and wastewater treatment facilities are very poor.

Drink a glass of fresh, cold water as you read this, and you may think that water pollution is only a problem of far away places. But while most Europeans have access to safe drinking water, potentially harmful contaminants, from arsenic to copper and lead, have been found in tap water in every EU country, as well.

Still, we are not hopeless against the threat of polluted water. To better understand the problem and what we can do about it, here is an overview of what water pollution is, what causes it, and how we can protect ourselves.

The current problem of water pollution

The discharges into the waters destroy part of the aquatic ecosystems. Some species end up disappearing due to the rapid proliferation of invasive algae, which are nourished thanks to all the nutrients that the waste gives them. These multiply rapidly, taking up the space and oxygen in the water.

photo: harmful algae destroying ecosystems

Freshwater pollution

Deforestation in coastal areas and the proliferation of construction make the soils in these areas vulnerable. The paving does not allow the passage of river water seepage when it rains, which favors salt water seeping beneath and thus, the contamination of fresh water. As we can see, water pollution ends up destroying part of the natural ecosystem.

When salt water penetrates the freshwater aquifers, logically the components of the water are no longer the same. This causes the extinction of certain species and the invasion of others that can take over the place. In general, they tend to be more aggressive species, which kill others.

The intrusion of these salt waters can also cause subsidence in the land. The abuse of the construction of wells or canals favors the filtration of salt water into freshwater marshes. It is also true that these salt waters can pollute naturally through storms, for example, when sea level rises.

Already when a tiny part of salt water mixes with fresh water, the latter is no longer drinkable. Therefore, the decontamination of water and its purification end up becoming a vital process.

Salt water pollution

Regarding the pollution that occurs in salt water, we can say that this is mainly of terrestrial origin, particularly as a consequence of the emission of wastewater and industrial tributaries into rivers, which then carry polluting substances to the sea.

The main source of marine pollution is hydrocarbons, particularly oil tankers, which sometimes release large quantities of oil into the water. An example is the ecological disaster caused by the sinking of the oil-laden ship Prestige near the coasts of Spain and France and the oil tanker Jessica along the coasts of the Galapagos Islands. These have caused serious environmental problems and many damages to the health of humans due to the arrival of polluting substances to the coasts.

In addition, salt water can suffer from these other contaminations:

Pollution off the coast:
Includes all contaminations far from the coast; often caused by the desired spill during tank washing or from bilge discharge of large units or again, from naval accidents due to storms, collisions, explosions, structural failures or accidents to extraction platforms.

Coastal pollution:
It is the most harmful and dangerous form of pollution, because it is very difficult to eradicate once it comes into contact with the coast. Due to low sea level, the various units used for the service cannot operate; since it is useless to use collection machines, such as skimmers.

Fundamental here is human intervention, with manual extraction, and therefore, the main field of action of volunteers cleaning up beaches and collecting recyclable materials such as plastic bottles and plastic bags but also other waste.

Underwater pollution:
This type of contamination usually occurs after a fire (such as that of the “Refugio” oil tanker in the Gulf of Genoa) when the light component of the hydrocarbon evaporates and the heavy component precipitates and deposits on the bottom.

It has been 17 years since the sinking of the supertanker Haven, the most serious oil pollution in the Mediterranean. The consequences of this tragedy, although limited thanks to timely and efficient management of the emergency, have not yet been exhausted. Even today, from time to time, small amounts of hydrocarbons come out of the main wreck, and there are still many tar depositions over a large area of the seabed. Therefore, a recovery operation is needed on the main wreck of the Haven to eliminate the risk of leakage of hydrocarbons and oils, fuels due to corrosion of materials and collapse of the structures of the wreck itself.

Consequences of water pollution

We know that fresh and salt water end up mixing under the earth, in groundwater, unnoticed by the human eye. It is estimated that around 13 million tons of freshwater end up flowing into the oceans every year.

The incorrect use of agrochemical products, dangerous elements that are discharged for example by not properly recycling batteries, the incorrect location and poor functioning of sanitary devices, such as latrines or pits, cause the soil to filter everything until it reaches the groundwater. The main contaminants found in groundwater, in addition to organic matter, are heavy metals, hydrocarbons, chemicals, microplastics etc.

Influence of contaminated waters on ecosystems

There are several causes of soil and water pollution. Probably the one that stands out the most is industrial pollution, followed by agricultural overexploitation, tourism, health centers and domestic waste. There should be more awareness under tourists to properly sort and throw away their waste from picnics such as food packaging, plastic bottles, plastic cups and plastic bags. Much of this waste can be recycled if sorted correctly. Also under normal households awareness of sorting and recycling waste has to be improved to prevent further water pollution. Another area where more measures are still needed to counteract pollution are the emissions from motor vehicles. The gases they emit also end up in the water, since everything that rises falls through precipitation, becoming more acidic and causing acid rain. There is still a lack of more measures regarding human behavior with spills and chemicals.

Another spill that causes great damage to ecosystems is oil. Unfortunately, there are few industries that take care of the environment seriously, making an economic issue out of everything. Waste and plastic recycling can be economically feasible if done the right way, though. It is not just a financial burden but can also be an economic gain model.

Lack of water

All these factors affect the health of humans and animals. In addition to negatively affecting other factors, such as the migration of animals due to lack of resources, for example. Food shortages and lack of decent water force them to change territory, and for those who are unlucky, death will follow.

Know the main sources of pollution

There are several polluting sources and they are classified as follows:

Point sources: Pollutants that come from this type of sources are those that access the place through fixed points, such as schools, industries, buildings, etc.

Diffuse sources: Here the source of pollution comes from varied, extensive and wide places. Urban sites, agricultural areas even atmospheric deposition.

Natural sources: These were caused by fires or volcanic activity.

Technological sources: Regarding industrial and domestic consumption, we are talking about chemical products. Also included are motor transports that require lubricants.

There are various degrees of pollution

The waters are divided into several zones according to the degree of contamination as follows:

Polisaprobiana: This area is characterized by being extremely polluted, with little oxygen and many organic compounds. Microorganisms abound in this place, especially anaerobic bacteria that are responsible for fermenting and decomposing.

Mesosaprobiana: This zone is characterized by being moderate. Organic substances are mineralized and oxidized. Bacteria are also considered, but they are not decomposers.

Oligosaprobian: This area is clean. Microorganisms are barely visible and there are no bacteria.

Saprobic: is the degree of contamination in waters that present the remains of decomposing animals or plants. This generates the influx of microorganisms and bacteria. To determine the intensity of the contamination of these waters, the presence of bacteria such as Escherichia coli or Streptococus faecalis, present in many humans, is taken into consideration.

Diseases related to contaminated water

Due to the characteristics it may have, water can be an important source of contamination for the transmission of countless diseases. These can be common, such as gastroenteritis, or also very serious, such as cholera, dysentery, typhoid fever, leptospirosis, among others.
Water contamination can cause certain diseases. The most important and worrying are the following:

This is the lack of red blood cells, which complicates the passage of oxygen to the muscles. There are different degrees, which can cause loss of skin color, drier lips and tongue, and damage to the nails and eyes.

A disease caused by food contamination, produced by bacteria that are usually found in conservation cans that have been poorly treated, there is no contagion between people.

A disease that can be spread between people, but is transmitted due to the bites of mosquitoes that have been in contaminated or water of poor condition. Although the mildest symptoms are fever, it can lead to death in more severe cases that are not treated.

Soil Pollution: Causes, consequences and how to solve it

Soil Pollution: Causes, consequences and how to solve it

There are many types of contamination of the soil that can have severely affect the environment. Let’s find out more about soil contamination below: what is it, what causes it, what are the consequences, why does it occur and how can we solve it?

What is soil pollution

Soil is the layer of organic and inorganic material that covers the rocky ground surface. The organic portion, derived from the decomposition of animals and plants, is concentrated in the upper part of the soil. The inorganic part is composed of rock fragments. Other components of the soil are water and air, which vary according to rainfall. Soil contamination, also called soil pollution, is caused by the introduction of chemicals or changes in the environmental soil by human activities. These chemicals lead to soil contamination and, directly or indirectly, to water and air pollution. Among these chemicals, the most common types are petroleum hydrocarbons, heavy metals (such as lead, cadmium, mercury, chromium, and arsenic), pesticides, and solvents.

Explained in other words, we can say that the soil is the unconsolidated loose material that is produced by the physical disintegration of the rocks, or the product of meteorological alterations in the environment.

The soil evolves until it can form a complex system, becoming a stratified structure and a specific composition, specifically under the influence of living beings.

But just like the atmosphere (air pollution), the soil can also be affected by pollution, something that – as you can imagine – is correctly called soil pollution.

Causes and consequences

The main causes of soil contamination are the use of fertilizers, pesticides, herbicides and insecticides, the incorrect disposal of solid waste and deforestation. These factors mean that the main consequences of soil contamination are reduced soil fertility, increased risk of erosion and loss of nutrients.

Below we explain more about the causes and consequences of soil contamination.

Use of fertilizers

Using them to correct soil deficiencies indiscriminately ends up contaminating the soil with impurities and/or nutrient overloading for plants, thus unbalancing the natural composition of the soil. Some heavy metals, such as lead and cadmium, are also found in fertilizers, increasing the toxicity of the soil and posing a great danger to plantations. These contaminants are subsequently removed with rainwater or infiltrate into the ground, ending up in groundwater tables and springs, thus contaminating watercourses.

Use of pesticides, herbicides and insecticides

Pesticides are used to reduce the number of pests that act on plantations and damage agricultural activity, despite the fact that they cause irreversible damage to the environment. These substances are absorbed by the soil, ending up contaminating the plantations that grow there. The subsequent consumption of these contaminated vegetables can cause serious damage to human and animal health. Another problem is the reduction of the fertility of the contaminated soil.

Improper disposal of solid and plastic waste

In general, domestic, industrial and rural wastes have in their composition a variety of chemical products like plastics that are harmful to the environment. This waste degrades and results in the production of leachate, which is a highly toxic liquid resulting from the decomposition of organic waste. Garbage deposits, made in an unsanitary manner, end up filtering this leachate, which crosses the soil, contaminates it and reaches the groundwater. The number of open air dumps around the world is worrying, since much of the rubbish is not properly disposed of. There may also be soil contamination from dumping radioactive material or hospital waste.


Natural soil erosion occurs when soil particles are carried by wind or water. Vegetation cover is removed during deforestation, removing protection from winds and eliminating water uptake by tree and plant roots. This excess water can cause soil instability and erosion.

Other causes of soil contamination are:

  • Contaminated water released by industries
  • Oil spill
  • Acid rain
  • Sewer discharged into rivers and land
  • Incorrect soil drilling
  • Cemeteries
  • Infiltration of septic tanks
  • Fires
  • Mining

Consequences of soil contamination

There are various damages caused by soil contamination. Among the main ones are:

  • Reduced soil fertility
  • Increased erodibility
  • loss of nutrients
  • ecological imbalance
  • Increased salinity
  • Reduction of vegetation
  • Public health problems
  • Release of polluting gases
  • Blockage of plumbing
  • Food contamination
  • desertification

Types of soil pollution

There are two types of contamination that can affect the structure and formation of the soil: natural contamination (which is frequently endogenous) and anthropogenic contamination (totally exogenous).

As we well know, and as we commented at the beginning, different natural phenomena can be important causes of soil contamination, as well.

To give just one example, an active volcano may be capable of contributing greater amounts of external substances and pollutants than several coal-fired power plants combined.

Soil contamination by human activities

Soil contamination can have a wide variety of causes. Some of the most frequent reasons are:

  • The use of pesticides in agriculture
  • Bursting underground storage tanks
  • Leaks from landfill or landfill areas leaking chemicals and plastics into the soil
  • Direct accumulation of waste from industrial products

The most common chemicals that are responsible for soil contamination are: petroleum derivatives (like plastics), pesticides, solvents, and other heavy metals. This phenomenon is a consequence of the high degree of industrialization, the increasing use of chemicals and the lack of management and control by both companies and the governments of the different countries.

When soil contamination reaches a critical level, the natural balance of these complex systems is affected, which translates into a change in soil behavior. What happens is that the harmful substances that accumulate become toxic to the organisms that live there. This chemical degradation can cause the partial or even total loss of soil productivity.

There are many negative consequences of soil contamination. Among them we can mention serious risks to human health, either directly or indirectly – caused by soil contaminants coming into contact with drinking water sources.

In order to carry out a good study of soil contamination, the maximum admissible levels of contaminants must be defined, and factors that may influence the response of the soil to these agents must be analyzed. Therefore, it is not enough to simply detect the presence of contaminated soil.

Once the contaminated areas have been defined, the area can be cleaned. But this does not constitute a true solution, since -of course- the effects of the contamination may have affected both the animals and plants of the place, as well as the health of the inhabitants and the productive quality of the soil. In addition, cleanup tasks take a lot of time and money, and usually cannot be afforded by the affected communities.

Negative effects of soil pollution

Soil contamination affects flora, plants and trees. Soil contamination causes a decrease in the variety of species, hinders their survival and, therefore, greatly affects the plant ecosystem of the contaminated area.

The same is true of wildlife. In nature, everything is closely related and, in the same way that soil contamination affects plants, it also affects animals. Herbivorous animal species may not have plants to feed on. Furthermore, contaminated soil greatly increases the risk for animals of falling victim to poisoning.

Soil contamination, like water pollution, causes a great impact on the landscape. Who likes to see an extension of natural land full of garbage, plastic bottles and bags and other polluting substances?

Soil contamination also causes a decrease in the quality of the surrounding soil, which makes it less useful for agricultural activities. Contaminated soil not only makes agricultural activities on that same land impossible, but also diminishes the quality of adjacent lands.

In the same way that soil contamination is detrimental to agriculture, it is also harmful to livestock, since the animals will not have quality pastures to feed on but eat microplastics instead. Soil pollution does not only affect the land we walk on. All these substances that contaminate the soil also contaminate the air, emitting polluting gases that affect the health of animals, plants and people, negatively affecting the ozone layer and accelerating the greenhouse effect.

On the other hand, this soil contamination not only contaminates the air, but is also likely to negatively affect nearby waters, both surface water and groundwater.

It should be noted that many of these consequences occur slowly, silently, but also inexorably. Soil contamination always leads to land that is unusable both for human activities and for hosting a healthy and varied ecosystem.

How to fight and prevent soil pollution

Some steps can be taken to control and reduce soil contamination. Reduce or eliminate the use of harmful fertilizers and pesticides (using biopesticides, for example), eliminate the use of disposable plastics, reforestation, control of the release of toxic waste from industries and, mainly, waste and plastic recycling, together with the correct disposal of waste and its treatment. However, these measures are not easily carried out and require considerable time to implement, in addition to investment in infrastructure.

In fact, and as in any case related to the contamination of the planet, man is up to his neck in it. In the same way that it is the human being that contaminates, it is also in our power to prevent and fight contamination of the soil, but also of water and air.

Regulatory laws

To all of the above, we can also add the approval of stricter laws and regulations regarding the emission of discharges by companies. The companies that produce energy and all kinds of products are the main culprits for soil contamination, especially due to the large number of discharges that end up in landfills. But if there are no laws promulgated by the government that harshly penalize this type of practice, they will continue to have a free hand.

In addition, it is necessary to invest in fighting pollution, invest in studies and professionals who know how to detect where the problem is and what the methods are to solve it. And, of course, invest in mechanisms and infrastructures that allow these solutions to be carried out. The problem is that, in many cases, the problem has been left to pass for so long that there are sources of soil contamination that nobody wants to deal with anymore, since cleaning up the area would require huge investments.

Ecological consciousness

Another of the key factors when it comes to preventing soil contamination is the awareness of human beings in their duty to respect the planet. We are constantly contaminating the soil with every little gesture. When we don’t recycle, when we throw things on the ground, they are small gestures that, multiplied by those same gestures in as many millions of people, give rise to an increasingly polluted planet. This also has a bit to do with people’s ignorance. Did you know that a plastic bag takes more than 100 years to disappear?

Often, helping to fight soil contamination is in your own hand. Help, collaborate, be part of cleaning or decontamination groups in affected areas. Do something that is in your power, contribute your grain of sand. Every gesture counts and the planet appreciates it.

Sustainable resources

The progress, the development of industrial activities and the exponential development of these, mining extractions, oil plants, nuclear energy, etc. Many of them are activities that are based on resources that, when discarded or stored, cause air and atmosphere pollution. Therefore, another of the solutions to soil contamination would be to finally take a step forward and look for other forms of production that are more sustainable and appropriate to the needs of the planet.

Clean and renewable energies are there, and they do not pollute, nor do biodegradable objects that could replace, for example, plastic bags.