contaminated aquifer

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Activities that should be considered essential for restoring a contaminated aquifer and the costs involved

Water is a right of the population and governments must ensure that no citizen is excluded from this public good. The inspection, control and performance mechanisms of the public power, when they are fragile in these essential services, make it possible for certain lobbies, in their eagerness for profit and waste water, to act with ease in this essential sector for life, often barring any technical- science contrary to corporate interests.

Aquifers, or groundwater reservoirs, are of fundamental importance for the survival of living beings and constitute about 95% of the fresh water available on Planet Earth, with only 5% forming rivers, lakes and dams.

Historically, when an aquifer is contaminated by human action, it is difficult for those responsible to end up receiving the calculation of the value or cost of the damage caused.

In the Brazilian case, due to the predatory environmental policy of that federal government on duty, taking as a reference the dismantling of IBAMA (Brazilian Institute for the Environment and Renewable Natural Resources) and ICMBio (Chico Mendes Institute for Biodiversity Conservation), the domino effect that this policy can have a devastating effect on state environmental agencies and compromise the process of managing contaminated aquifers and their respective restorations.

At this point, it never hurts to remember that the path of water in the earth's crust is quite complex. Because of solar energy, a water molecule, by an infinitely large number of stimuli, can be evaporated from the ocean and return to it precipitated by the rains. It can also fall on the continents, infiltrating the ground below, be absorbed by plants or return indirectly to the seas through rivers and streams. It can accumulate underground and form aquifers or groundwater reservoirs.

The recharge water of underground reservoirs comes from precipitation or from surface water bodies, or even from other aquifers with which they maintain a hydraulic connection. Thus, the flow of groundwater is governed by the physical characteristics of the environment, composed of soils and rocks and, most of the time, does not respect the political divisions of municipalities, states and countries.

Contamination of soils and waters by elements, compounds or organisms that may harm human or animal health can occur both in urban and rural areas and is one of the major concerns of the modern world. When contamination does not have a natural origin, being caused by dissolved constituents of minerals that make up rocks and soils, contamination can come from human activities and ends up reaching surface and underground sources.

In this way, the restoration of a contaminated aquifer or a portion of it, which would be the integral and complete repair of the contaminated area, must be understood when the groundwater returns to present the same parameters of natural chemical quality of the aquifer medium and not containing contamination of anthropic origin, resulting from a progressive deterioration of this aquifer.

In this line of reasoning, the restoration of an aquifer needs to happen in the same scenario, for example, the restitution of an ecosystem or a degraded wild population, as stated in Federal Law 9.985/00, article 2, item XIV, which deals with a kind of repair in natura e , and its recovery, seeking to return as close as possible to its original condition.

However, for restoration to occur, one of the key points in the issue of valuing the damage of a contaminated aquifer or a portion of it concerns the dominance of groundwater. Groundwater located in aquifers is not an extension of the soil surface and, therefore, these reservoirs do not belong to landowners or superficies.

For this reason, for the valuation of the environmental damage of a contaminated aquifer to be effective, for example, costs with hydrogeological and hydrogeochemical studies, complemented with soundings, geophysics, sampling and water analysis, aiming at monitoring contamination and gathering data. for conceptual and mathematical modelling, during the management and restoration process of the underground reservoir.

In addition, the costs of the temporary “loss” of using the aquifer or a portion of it should also be included, which would account for the costs with possible wells that could have been built as sources of supply, plus an indemnity for cause of the environmental damage caused by the compromise of ecosystem services.

In this context, it is emphasized that groundwater is considered public domain property of the States of the Federation by virtue of Article 26, Item I, of the Federal Constitution and it is up to the States to manage it.

In conclusion, this article, which sought to show the activities that should be considered essential for the restoration of a contaminated aquifer and the costs involved, draws attention to the phrase by the writer João Guimarães Rosa, which is more and more relevant every day: “Water good quality is like health or freedom: it only has value when it ends”.

*Heraldo Campos He holds a PhD in Sciences from the Institute of Geosciences at the University of São Paulo (USP).


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