You mightn’t be able to see it, and it may be difficult to obtain, but the human race has drawn on groundwater for water supplies for thousands of years. This much can be seen from archaeological remains in places such as the Motillas de Daimiel in Spain, one of the oldest well sites in the world, with over 4,000 years antiquity. Such structures, as well as reaching groundwater underground, served to conserve and protect them as a precious source. Today, however, one of the big problems we face is increasing groundwater pollution due to human activities and climate change.
What you’ll find in this article
- The water lying under our feet
- The threat of groundwater pollution
- Main causes of groundwater pollution
The water lying under our feet
At the dawn of the 20th Century a new science was born: hydrogeology, the study of the origin, dynamics and role of underground water in nature.
Up until then, great thinkers such as Leonardo da Vinci advanced the theory that underground water came from the bottom of the sea, filtering out the salt as it rose during its underground voyage.
“Hydrogeology studies the origin, dynamics and role of underground water in nature”
Today we know that groundwater is the result of a natural cycle. Some of the water that falls in the form of rain or snow seeps down through the ground, when the latter is permeable, reaching the subsoil and collecting and storing in what we know as aquifers.
The passage of this water is usually very slow and can remain in the subsoil for years, centuries or even millennia, before it reaches wellsprings or other sources that can be drawn on that, on occasions, give rise to wetlands of great environmental import. This is why it’s crucial that we refrain from polluting groundwater.
The threat of groundwater pollution
Most potable water is found below Earth’s surface and in this case is called groundwater. It is one of the main sources of water that is apt for human use and is consumed by almost a half of the world population. As well as being used by sectors such as agriculture, it is indispensable for the sustainability of a wide variety of planet ecosystems.
Nonetheless, human activities and climate change are causing the pollution of groundwater, even though it benefits from much more natural protection than surface water. It is also much more difficult to detect the presence of pollutants in groundwater, to stop them reaching it and to rid them from the water.
“Human activities and climate change are causing the pollution of groundwater”
Groundwater pollution causes serious problems for both the health of people and of the planet. The presence of nitrates, heavy metals and other compounds that alter the composition of this resource and diminishes its quality make it dangerous for humans to consume and to use in other ways.
Main sources of groundwater pollution
The fundamental causes of groundwater pollution can be broken down into four groups, in relation to the kind of human activity that produces
- Urban and domestic pollution: in this we include sewage water and pollutants from waste tips and the drainage network. The most efficient way of preventing this is through rigorous control of town water and correct sewage treatmen
- Agricultural pollution: fertilizers, pesticides and animal manure can seep through to freshwater sources and impoverish the quality of the water
- Industrial pollution: industrial waste, mines and leaks from fuel tanks can cause one-off pollution events
- Pollution caused by pumping: known as marine intrusion. The mix of seawater with freshwater in coastal aquifers is one of the most frequent forms of pollution and difficult to control on coastlines and islands.
Sustainable use and protection of groundwater is one of humanity’s biggest challenges. Freshwater sources are indispensable for human water supply and the performance of agricultural and industrial activities, while they are also necessary for the survival of ecosystems. Avoiding groundwater pollution is vital for life.