Monitoring carried out by Inea, the environmental agency of the government of Rio de Janeiro, indicates that the water quality of Guanabara Bay has deteriorated in the last two years.
All collection points in the water mirror showed averages considered bad or very bad during the monitoring carried out in 2020 and 2021. This is the first time that this has occurred since 2014, the beginning of the survey’s historical series.
Neither Inea nor experts can explain exactly the reason for the result. The hypotheses were the worsening in the maintenance of the sewage system by the state in the imminence of the concession of the basic sanitation service, carried out last year, and a possible effect of weather conditions at the time of collection.
The worst result of the historical series was recorded precisely when the promise of depollution of the Guanabara Bay was renewed with the investment plan required by the new concessionaire, Águas do Rio, which will operate in its surroundings.
The company took over the region’s basic sanitation at the end of last year and expects to improve its results in five years.
According to Inea data, 13 of the 20 monitored points within the bay had an average considered to be very bad in the last biennium. The other seven collection sites were considered bad.
The state agency’s report refers to the average of the seven collections made between 2020 and 2021. The survey is usually annual, but it suffered interruptions two years ago due to preventive measures during the new coronavirus pandemic. For this reason, the bulletin refers to the biennium.
In the analyses, the institute verifies 15 physical-chemical and biological parameters of the water, such as the presence of fecal coliforms and phytoplankton, microorganisms that indicate the presence of pollution.
The result is the worst ever presented in the historical series. Before, the year with lower averages was 2014, the first, when 13 points were considered very bad, 5 bad and 2 regular.
The best result was achieved in the 2016/2017 biennium, after the Olympics were held in Rio de Janeiro, when only five points were considered bad, three bad, nine fair and three good. This was the only period with any point with a positive index.
Since then, the waters of the bay once again showed progressive worsening.
Despite being completely associated with the sewage disposal of the 16 cities that make up its hydrographic basin, the water mirror of the bay is diverse.
The areas close to the Guapimirim environmental protection area usually have better waters, due to the environmental preservation of the surrounding rivers in the region. In addition, the bay has a deep central channel that favors the exchange of water with the sea in a more intense way, diluting the dirt.
However, even these points showed poor results in the last biennium.
The collection point near the beach of Icaraí, in Niterói, registered for the first time an average considered to be very bad. In the five previous surveys, the location was considered regular three times, once good and once bad.
Even the external monitoring point near the mouth of the bay, already in an oceanic area, had its result considered bad for the first time in the historical series.
When contacted, Inea stated that “there was no significant change in the water quality of the monitored points in Guanabara Bay”.
experts heard by Sheet do not identify a specific reason for the results. All say, however, that the worsening trend remained in the analyzed period.
State deputy Carlos Minc (PSB-RJ) points out as one of the hypotheses the reduction of investment by Cedae, state-owned until last year responsible for the sewage system of almost the entire metropolitan region, due to the expectation of the concession of the basic sanitation service of State.
“In fact, I heard reports that there was an orientation to reduce spending on maintenance and hiring teams, since the private sector would take over”, said the deputy.
Biologist Mário Moscatelli says he does not see a reduction in Cedae’s performance in the period. For him, the company has always prioritized the production of water to the detriment of sewage collection. “I don’t think there has been a change, but a company culture.”
In a note, Cedae stated that the information that it reduced investments before the concession is not correct. “In 2020, Cedae invested 11 times more than it invested in the previous year. In 2021, investments increased three times compared to 2020.”
Minc also points to the relaxation in the inspection of state and federal environmental agencies as another possible reason for the worsening in the result.
“Supervision is weaker. Inea has fewer people. And, in federal agencies, there is a political orientation not to act. Ibama is completely gagged, with its hands tied”, said Minc.
Professor Paulo César Rosman, from Coppe/UFRJ, says that the monitoring carried out by Inea has limitations that make it difficult to compare the results in the historical series.
“They [coletas] are done when there is time. It’s almost a lottery. In a water system controlled by regular events, such as tides, and irregular, which are weather conditions, a pattern is essential,” he said.
All claim to have an expectation of improvement in results in the next five years, after the start of operations at Águas do Rio. An emergency investment of R$ 2.7 billion in this period is planned to accelerate the end of the dumping of waste in the bay.
The concessionaire has already decided to divert the course of the Carioca River, which flows into the bay at Flamengo beach. The polluted waters will be directed to an interceptor that will forward them to the Ipanema submarine outfall. The intervention will last until the watercourse is cleared.
