February 6, 2023

10:02

Ívina Garcia – Amazon Agency

MANAUS – Surrounded by the waters of the Negro, Solimões and Amazonas Rivers, Manaus has the waterway as one of the main means of tourism and transportation. The city’s hydrography has four main basins: Educandos, São Raimundo, Tarumã and Puraquequara.

Intersected by creeks and small lakes, the city mixes urban pieces and modern buildings, with creeks, bridges, and ports. Despite being surrounded by water, many of the watersheds are unsuitable for drinking or leisure.

According to the Sustainable Development Goals (SDGs) of the United Nations, access to drinking water is one of the main factors that help reduce inequalities and ensure a better life, with access to health and quality of life.

From this, a pioneering study of the Amazonas State University (UEA) mapped the main points of the basins of Educandos and São Raimundo over two years, between February 2020 and January 2022, to put into practice the environmental mapping project that checks the water quality.

In all, 14 points were collected in the Educandos Basin and 31 in the São Raimundo Basin, considered the main ones in the capital, to generate the Water Quality Index (WQI), with a series of parameters used in international research.

At first, the study crossed the data obtained with figures used in São Paulo and Rio Grande do Sul. However, the researchers noticed that the Amazon basin presented differences that could not be measured by non-regionalized parameters.

According to the researcher and coordinator of the study, Dr. Sergio Duvoisin Junior, the numbers obtained in the research are still inaccurate, because once the parameters disregard the regional sphere, the data do not reflect the true quality of the water in Manaus.

“While we don’t have this [regional] index here, we use the one mapped in São Paulo and Rio Grande do Sul. They are completely different waters, so sometimes we may be inferring results that are not exactly what they should be”, explains Junior.

The next step, according to the researcher, is to generate the Amazon IQA, using the specificities of the region, considering the basins’ own chemistry and acidity. Campaigns with teams of researchers have already started visiting places with no human action to start defining the index in the state.

“From this project we saw that here, in Amazonas, there was no water quality index that characterized the water here without human action. So, this was the motivator even for the projects that came later, of us starting to monitor the water in places far from the city, to set up an IQA that really represented the waters of the region”, he reports.

The coordinator exemplifies that the IQA in São Paulo, for example, considers that the pH (hydrogenic potential) considered as optimal is around 7 points, different from what is observed in Rio Negro, where the average is below 5 points.

“If we were to compare the data from here, which are between four and a little bit and five points, with the table from São Paulo, the water would be bad, but this is not true, because the water from Rio Negro has a pH around four and five. That is why the IQA adjustments need to be made for the region”, says Júnior.

Besides mapping the water quality, the project works as a monitoring of discharges. Part of the research collected water in places near factories in the Industrial District.

“They are the two main basins most impacted in Manaus. It is extremely important to monitor them because they pass through regions where there is a large population or in the Industrial Center, so we can have things being dumped there that are not domestic”, says the research coordinator, who says he is in talks to reactivate the monitoring project with the Special Projects Management Unit (UGPE).

Results

The results obtained by the research are available for consultation on the site of the Chemical Research Group Applied to Technology, of the Amazonas State University (UEA). The research is available for the population to have access to information about the water quality in the places where they live.

According to the researcher, the results were already expected by the group. “I think that anyone who walks by these watersheds and looks at them knows that the quality is not that great, the thing is that the project ended up pointing out what was really happening,” he says.

See the IQA table used in Brazil:

Each parameter has a color, blue for excellent, green for good, yellow for fair, red for poor and black for bad. The research in the Educandos and São Raimundo watersheds considered the two ranges, in both of which the IQA registered was, on average, 30, with a “bad” evaluation for both.

The Educandos basin had an average of 31, with four black points, with very bad quality; 68 red points, with bad quality; 24 yellow points, with reasonable quality; two green points, with good quality and no blue points, with excellent quality.

“This reflects this distortion that we have of the IQA for the region, requiring an index that really identifies us as the water quality of this macro basin that are these black waters”, evaluates the researcher, who points out that besides the IQA, a classification based on the parameters of the National Council for the Environment (Conama) was carried out, divided into classes from one to four, in which the Educandos basin is within class four, the worst of all.

In the São Raimundo basin, which is not an industrial affluent and has more domestic waste, the IQA recorded also showed bad data. With an average of 32, the basin presented seven black points, with very bad quality, 130 red points, with bad quality; 69 yellow points, with reasonable quality; 11 green points, with good quality and no blue point, with excellent quality.

“The São Raimundo basin is also compromised in the same way as the Educandos basin, and classified as class 4 in Conama. This shows that both basins are very compromised”, he evaluates.

For the coordinator, the research is an important step for environmental monitoring and serves as a tool for managers, both environmental and state, to generate improvements for the population.

“Today the public manager has a gigantic tool in his hand, through which he can know exactly at what point we are performing inadequate dumping, because this project we ended up doing kilometer by kilometer in the two basins, mapping out very well what is wrong”, he stresses.

According to Sergio, the basins are very compromised and now that the extent of the problem is known, it is possible to act to correct it. “Now we have to use this tool and really try to solve it. This part goes through the management, we show the problem, and now it is up to the public management to give a solution”, Sérgio concludes.