The water is a natural element that makes up not only the Earth, forming the hydrosphere , but also the human body , and therefore essential to the existence and maintenance of life. Found in the three physical states , water is present in oceans, seas, rivers, lakes, glaciers and also in underground reserves.

It is essential for practically all activities performed by human beings, whether in the sectors of the economy , such as agricultural and industrial production, or in acting as a universal solvent . However, the waste and irrational use of water has caused its lack in several regions of the world, which is one of the greatest concerns of the century.


We can define water as an abundant natural resource , characterized by being liquid , colorless and tasteless . In addition to the liquid state, this resource can also be found in the solid state, constituting glaciers and snows, and also in the state of vapor, found in the air and constituting clouds and fog.

Also read: Water-related diseases

Don’t stop now … There’s more after the publicity;)


Potable water

Drinking water is defined by the Ministry of Health, through Ordinance No. 1,469, as being: “water for human consumption whose microbiological, physical, chemical and radioactive parameters meet the potability standard and does not offer health risks ”.

Therefore, it is water that can be consumed when it meets the necessary requirements that guarantee the safety and well-being of those who use it. To be considered drinkable, it must be odorless, colorless and tasteless, as well as not having pathogenic organisms capable of causing disease.


Water on the planet

The water on the planet is not evenly distributed, varying according to regions and the existence of ecosystems.

The planet Earth is composed of an extensive body of water that comprises the oceans, seas and waters existing on the continents, totaling approximately 1.4 billion km 3 .

The Earth is known as “Water Planet” because it has about 71% of its surface covered by liquid water. Of this total, 97.5% of the available water is salty and unfit for consumption. Only 2.5% of the available water is sweet . Salt water is found in the oceans and seas, and fresh water is found in rivers, lakes, glaciers, eternal snows and underground reserves.

The water on the planet is not evenly distributed among the regions . Its distribution varies according to numerous factors, such as location , physical characteristics , climate , presence of ecosystems , among others.

Fresh water is more widely available on the American continent , according to the National Water Agency. Of the total available in the world, 39.6% are on that continent. The continent with the lowest water availability is Oceania, concentrating around 3.9%.

Also read: Tips to save water


The water cycle is responsible for maintaining the volume of water on Earth.

The hydrological cycle is responsible for maintaining the volume of water on the planet , being defined as the circulation of water, in its three physical states, between the surface and the atmosphere. How does it happen?

The continental waters found in the liquid state undergo the evaporation process due to the action of the Sun, which affects the sun’s rays, causing evaporation . The vapor that forms rises to the atmosphere, forming clouds. These, laden with moisture, precipitate like rain, snow or hail. After that, the water returns to the Earth’s surface . Throughout this process, some of that water evaporates before it even reaches the ground; part replenishes oceans, seas, rivers and lakes; part infiltrates the soil supplying the underground water reserves. Then, the cycle starts again.

To learn more about, visit: Water Cycle


According to the Ministry of the Environment, water can be used in two ways:

Consumptive use Non-consumptive use
Water is used directly to supply people, to feed animals, to irrigate agricultural products, etc. This type of use affects the amount of water available on the planet. Water is used indirectly for leisure activities, navigation, power generation, etc. This type of use affects the quality of the water available.

Data from the Food and Agriculture Organization of the United Nations reveal that about 70% of the consumption of water available in the world is for the agricultural sector. The industry is responsible for about 22% of consumption, and domestic supply , about 8% , according to the Ministry of the Environment. In Brazil, approximately 60% of the water consumed is used to make agricultural production viable. The industrial sector consumes around 17%, while only 9% is devoted to domestic supply.

Water in Brazil

Brazil is a privileged country when it comes to water. The country has one of the largest freshwater reserves in the world, accounting for approximately 12% of the world total . The region with the greatest availability of water in Brazil is the North region , concentrating around 68% of the water reserves. The Northeast region is the one that suffers most from the lack of the resource, concentrating only 3% of the water resources.

This large availability of water is also accompanied by an enormous amount of wasted water. According to data from the Ministry of the Environment, about 20% to 60% of water, varying in the regions, is wasted during distribution , showing a failure in the country’s supply systems . The habits of the population also reinforce waste , especially in activities of personal use and cleaning .

Water molecule

The water molecule is made up of two hydrogen atoms and an oxygen atom connected through covalent bonds . The water formula is H 2 O, and its shape is similar to a V. The water molecule is polar, and the positive hydrogen of one molecule is attracted by the negative oxygen of another, forming the so-called hydrogen bonds.

The water molecule has two hydrogen atoms and one oxygen.

In liquid form, the hydrogen bonds established between the molecules are fragile, and the formation and rupture of these bonds is constant. This characteristic is responsible for the fluidity of the water. In the solid form, the bonds are more rigid, and in the gaseous state, there is no great aggregation of water molecules.

Functions in the human body

As we know, water is essential for the existence of life on our planet . All living things depend on water in some way, including humans. Water is fundamental for the functioning of our body and is the most abundant constituent of our organism , with the human body being composed of about 70% water. This substance is in greater quantity in thin people, with a lower percentage being found in obese people.

The human body has about 70% water.

See below a chart with the main activities performed by water in the human body:

Role of water in our body
Transport of substances Water is one of the main components of blood plasma, and it is through plasma that various nutrients reach the cells.
Medium for chemical reactions Many chemical reactions only occur in an aqueous medium.
Protection Water is present, for example, in the amniotic fluid that protects the fetus inside the uterus. In addition, it is also present in our tears, which protect the eyes, and in cerebrospinal fluid, which acts to protect the central nervous system.
Lubricant Water is present, for example, in the synovial fluid, which is located in the joints. This liquid works as a lubricant, preventing friction between the bones.
Regulation of our body temperature Water is present in sweat, in the substances that act in the thermoregulation of our body. On very hot days or when we practice physical activities, it is common to release sweat. Its evaporation causes body heat to dissipate.
Waste disposal Water is part of the urine, which contains substances that were in excess in the body and waste products of metabolism.

It is noticed, therefore, that water is needed all the time in our organism, and, due to the inability to store it, we must often replace it. It is worth noting that our bodies lose water in different ways, such as through sweat , urine , feces and the breathing process .

Amount of water to be consumed daily

We must drink water daily for our glass to work harmoniously. Lack of water can cause an individual to die in less than a week, unlike the lack of food, which only takes a person to death in about 30 days. Given the importance of water, what would be the ideal amount to be ingested daily?

Without water, we can die in less than a week.

The Ministry of Health’s recommendation is to drink at least two liters of water every day. This recommendation is increased when the days are very hot or when the individual practices physical activity. It is worth noting that some professionals emphasize that the ideal is that 35 ml of water be ingested per kilogram of weight, per day. That is:

Liters of water daily = 35 x weight

Using the calculation above, we can conclude that, for example, a person with 60 kg will have to consume 2100 ml of water, that is, a little more than two liters. To find out more details on the topic, access this specific and very detailed content: What is the ideal amount of water that we should drink daily?

Water-related diseases

Water is essential for our survival, however, it is often also related to the development of diseases. Here are some situations in which water may be related to disease:

Dengue, zika and chikungunya are related to water, as their vectors place their eggs in the water and their larvae develop in that environment.

  • Diseases related to ingestion of contaminated water:When we ingest water contaminated by some pathogenic organism, we can develop some diseases. Among the diseases related to the ingestion of contaminated water, we can mention: giardiasis , rotavirus, amebiasis , cholera and hepatitis A.
  • Diseases related to contact with contaminated water:Some diseases related to water do not require ingestion of this substance, just by simple contact. Among the diseases that are transmitted by contact with contaminated water, we can mention: leptospirosis and schistosomiasis.
  • Vector-related diseases that develop in the aquatic environment:Some vectors (the agent responsible for transmitting the disease-causing agent) develop in the water, requiring attention with standing water. Mosquitoes vectors of some known diseases, such as zika , malaria and dengue, show part of their development in this environment.
  • Diseases related to lack of water, lack of sewage treatment and poor hygiene:Lack of water is directly related to poor hygiene and the appearance of diseases. The lack of sewage can also be responsible for promoting the transmission of diseases, such as worms.

In general, we can avoid water-related diseases with very simple attitudes, such as:

  • always wash your hands, especially before and after going to the bathroom and when handling food;
  • wash food well;
  • drink only treated, filtered or boiled water;
  • do not bathe in places that may be contaminated;
  • avoid exposure to flood water;
  • take care to avoid the proliferation of vectors, not leaving, for example, water accumulated in tires and bottles.

To see more about, visit: Water-related diseases

Water is an abundant natural element on Earth that is found in three physical states: liquid, gaseous and solid


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