By HERALDO CAMPOS*
The case of the São Paulo State Coastal Aquifer
“The world was not made in alphabet. But first in water and light. Then tree.” (Manoel de Barros).
The restoration of a contaminated aquifer or a portion of it must be understood in the same context as the restoration of an ecosystem or a degraded wild population as close as possible to its original condition, as stated in Federal Law 9.985/00, article 2, item XIV, in the case of a kind of reparation in natura e in situ, as well as its recovery.
In this context, the restoration of a contaminated aquifer or a portion of it would be the integral and complete repair of the contaminated area, taking place when the groundwater again presents the same parameters of natural chemical quality of the aquifer medium and does not contain contamination of anthropic origin. , arising from a progressive deterioration of this aquiferous medium that can occur, for example, by urban, industrial and/or agricultural expansion that make it impossible to use the underground water resource due to the damage caused.
In this way, the restoration of the aquifer or a portion of it in this article, for the case of the State of São Paulo, is understood here as when the reservoir returns to present the same parameters of natural chemical quality based on the data published in the Groundwater Map of the State of São Paulo[1] shown in Figure 1.
Figure 1. Groundwater Map of the State of São Paulo.
For this understanding, the example used here refers to the natural chemical quality of the groundwater of the Coastal Aquifer located in the State of São Paulo, which according to the aforementioned study has the following characteristics: “The Coastal Aquifer is distributed irregularly along the coast, segmented through the rocks of the pre-Cambrian basement, from the region of Cananéia, to the south, to the region of Caraguatatuba and Ubatuba, to the north. It consists of sedimentary deposits from the Coastal Plain, which reaches 70 km in width, in the great plains of the Ribeira de Iguape river valley, reducing from Itanhaém, Santos and Bertioga, towards the north, where small isolated pockets , 300 m long are more characteristic.”
Figure 2. Coastal Aquifer. Groundwater map of the State of São Paulo.
Figure 2 shows the delimitation of the Coastal Aquifer and the natural chemical quality of groundwater in this underground reservoir can be summarized as follows: “Total iron is the most restrictive chemical element, with an average of 1,39 mg/L. However, this problem can be easily corrected by simple aeration techniques (DAEE, 1979a). Most wells have salinity below the standard of 1.000 mg/L, being higher in the Santos-Cubatão region, where chloride is above 250 mg/L, which indicates contamination by the saline wedge.”
As in this example, the groundwater may be naturally contaminated by the saline wedge and, consequently, unfit for human consumption, but, due to its natural chemical characteristics, it may favor a suitable environment for the development of certain crustaceans such as tatuí or tatuíra (emerita brasiliensis) and the corrupt (callichirus major), very common crustaceans found on the sands of beaches in São Paulo (Figures 3 and 4).
Figure 3. Crustacean tatuí or tatuíra (emerita brasiliensis) that lives on the sandy beach strip in an environment of non-potable salty underground water. Ecosystem service provided by the Coastal Aquifer: biological regulation.
Figure 4. Corrupted crustacean (burrowing crustacean callichirus major) that lives on the sandy beach strip in an environment of non-potable salty underground water. Ecosystem service provided by the Coastal Aquifer: biological regulation.
Thus, considering that one of the ecosystem services provided by aquifers or underground reservoirs is biological regulation, the Coastal Aquifer, in this example presented, due to its natural chemical characteristics (with salty groundwater), can favor the development of tatuíras and corrupt .
In other words, if by chance an accident occurs, such as the leak of a fuel tank at a gas station on a strip of beach sand, with groundwater naturally useless for human consumption, the role of the underground reservoir in biological regulation, in the presented context, it would be somehow guaranteed and should, necessarily, be preserved.
However, the removal of the corrupt crustacean (digger crustacean callichirus major), which lives in the subsurface of the sand strip of Praia do Perequê Açu in Ubatuba (SP), was observed during the summer season of 2020, during the months of January and February, and also at other times of the year, mainly when the The tide is low, which makes it easier to catch.
The removal of this type of crustacean, using suction pumps, generally used as bait for fish, can cause changes and environmental consequences, both in this specific species and in other existing ones, such as, for example, the crustacean tatuí or tatuíra (emerita brasiliensis). Thus, as additional information, on the sand strip of beaches in the municipality of Praia Grande, São Paulo, Municipal Law nº 789 of 1992 prohibits the commercialization or use of suction pumps for the extraction of this crustacean, aiming at its protection in this context. habitat natural.
Finally, from the above, it is concluded that the parameters of natural chemical quality of groundwater presented in the database published in the Groundwater Map of the State of São Paulo strengthen the idea of the importance of ecosystem services provided by underground reservoirs, one of which is biological regulation.
* Heraldo Campos, a geologist, is a postdoctoral fellow at the Department of Hydraulics and Sanitation at the School of Engineering of São Carlos-USP.
Reference
DAEE (Department of Water and Electric Power), IG (Geological Institute), IPT (Technological Research Institute), CPRM (Brazilian Geological Survey). 2005. Groundwater Map of the State of São Paulo. Sao Paulo: DAEE. (3v, map and CD-ROM).
