Among 90 rivers and water bodies analyzed in the Atlantic Forest, the most devastated biome in Brazil, about 20% have poor or very poor water quality and more than 70% have regular quality, which would be a warning sign, according to an analysis carried out by the Observando os Rios project, by the NGO SOS Mata Atlântica, sponsored by the company Ypê.
The Observando os Rios report was released this Tuesday (22), the world water day.
Poor or very poor quality freshwater means that it cannot be used for basic uses such as supply, animal hydration, food production, and even leisure and sports. Regular quality water, after treatment, allows some of these uses (swimming in regular water, however, is not an option), but that doesn’t mean it’s okay.
“It’s a warning that if you’re not careful, it will get worse”, says Gustavo Veronesi, coordinator of the Observando os Rios project, from SOS Mata Atlântica, referring to the 72% of samples with regular water quality. “It’s a big warning sign. Regular quality water can be used, but it’s in danger, it’s on the yellow light.”
Water samples were collected last year at 146 points in 90 rivers in the biome. This is the second time that the project has been carried out in all the states of the Atlantic Forest.
The project bases its analysis on the so-called IQA (Water Quality Index), which was adapted from the National Sanitation Foundation, in the USA, and observes the most relevant physical, chemical and biological parameters for the evaluation of fresh water used for public supply and several others. uses. Among the parameters observed are water temperature, turbidity, foams, floating garbage, odor, fish, dark and transparent larvae and worms, total coliforms, dissolved oxygen, phosphate and nitrate.
The result of the 2021 analysis is not very different from what was found in 2020. According to Veronesi, it is expected that the changes from one year to the next will not be profound. After all, polluting a river is a relatively quick process, while to clean up the pollution is another and much longer story.
“The river is not dirty. They may be dirty, but no river is dirty. We dirty the river, so we have the responsibility to clean them up”, says Veronesi.
The work of Observando os Rios is not able to embrace all the water bodies of the Atlantic Forest, despite being able to currently follow rivers in the 17 states of the biome and the desire to expand the area of ​​action. In any case, the project coordinator says he believes that the results in other places should not be very different from those found in the places already observed.
Much of the water contamination found by the project is derived from sewage. It’s not for less. According to 2020 data from the National Basic Sanitation Survey, from the IBGE (Brazilian Institute of Geography and Statistics), almost 50% of Brazilian households, or 34.1 million homes, did not have access to sanitary sewage network. In addition, almost 40% of the municipalities did not have this service in 2017.
The regulatory framework for basic sanitation predicts that, by 2033, sewage treatment and collection should reach 90% of Brazilian homes, something that Veronesi says he hopes will happen, but that he has doubts about the real possibility of carrying it out, considering the current scenario.
The case of the Tietê River in São Paulo is a good example of the difficulty of changing the course of pollution in a body of water. Even after nearly three decades of depollution project, it was only recently possible to see punctual improvements, in some stretches.
But, at the same time, these points of improvement in Tietê show that it is possible to act on pollution. Veronesi cites the points at the outlet of the river in the metropolitan region of São Paula, in Santana do ParnaÃba and Pirapora do Bom Jesus, which used to have poor and even terrible water quality, but are currently regular.
The last specific analysis of the Tietê river, also carried out by the Observando os Rios project, observed the continuity of the reduction of the pollution spot in the water body and the increase of the stretches with good water, maintaining the improvement trend.
Another good example is the lake at Ibirapuera Park, which is fed by the Sapateiro stream, which is part of the Pinheiros-Tietê system. According to the coordinator of Observando os Rios, the depollution work on the two major rivers ended up positively affecting the lake in the most famous park in São Paulo, which now has good quality water (it used to be regular).
“This is quite significant because it is part of the Pinheiros River project, which has a very poor quality and will still take time to get bad. It is not from one mandate to another that it improves. We need to stop thinking about sanitation and water management in mandates of four years”, says Veronesi.
The coordinator of river analysis actions also highlights the importance of the volunteers who are part of the project. The idea is to always be people who live very close to water bodies, so that they can always keep up with what is happening in the place and live up to the name Observando os Rios.
