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SDGs Planet

SDG 6 – Clean water and Sanitation

The development and well-being of human societies has been inevitably linked to the availability

of freshwater in sufficient quantity and quality to meet the needs for various uses (from domestic
to industrial). Once used for such activities, water loses quality and needs to be treated to make
it suitable for use again. When the water used is returned to the environment (e.g. rivers, lakes or
lagoons) it undergoes a natural purification process. The organisms that live in the water eliminate
both inorganic and organic pollutants. However, when the water intake is excessive, the self-
purification capacity is exceeded and the water is no longer suitable for domestic and many

industrial uses (Vigil 2003). In addition, as one moves along the rivers from the headwaters to the
mouth of the river, the downstream population centers receive water contaminated by waste from
upstream populations. It is therefore necessary to treat the water before using it for its various
uses. The simplest system would require:

a) making the water drinkable before it is used in households,

b) an adequate piping network for transporting drinking water and collecting wastewater,

c) treatment before returning the water to the natural environment.

Lack of access to these systems increases infant mortality rates and decreases life expectancy
very significantly due to the spread of diseases caused by viruses and bacteria. There are about
500,000 (the size of a city like Dresden, Gdansk) deaths per year related to the consumption of
unsafe water. Globally, one in three people do not have access to properly treated water, two out
of five do not have a basic toilet (sometimes even health centers lack clean water) and almost
700 million people defecate in the open.

From another point of view, the return of untreated or inadequately treated wastewater to the
environment affects aquatic ecosystems. Various groups of organisms, including fish, are capable
of concentrating pollutants in water. Elements such as heavy metals, complex chemical residues
such as drug residues or household plastics are incorporated into the animals through the gills

and digestive system. Many of these pollutants cannot be eliminated and end up severely harming
individuals living in polluted waters. Indirectly, they can also cause human health problems when
these fish are part of the diet. On the other hand, the arrival of inorganic elements such as nitrogen
or phosphorus causes an excessive and unbalanced growth of microscopic algae that form part
of the plankton, causing eutrophication in bodies of water. This leads to serious alterations in the
state of aquatic ecosystems and even to the extinction of species. The development of low-cost
technologies for water purification and sanitation networks is crucial for preserving both human

health and the good condition of ecosystems.

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