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.