The survey measured the water quality in 177 points of 96 rivers in seven Brazilian states and found that 40% presented poor or poor quality.
In all, 87 analyzed points (49%) had their water quality considered regular, 62 (35%) were classified as bad and 9 (5%) presented a bad situation.
Only 19 (11%) of the rivers and springs showed good quality. And none of the analyzed points was evaluated as optimal.
In addition to the worrying numbers, the study shows the key role of caring for the natural environment in ensuring good quality water.
All 19 points that fit into this category are located in protected areas and have preserved riparian forests.
In the list of best results, protected areas of the Upper Tietê Basin enter the Environmental Protection Area (APA), Capivari-Monos and the Várzeas do Tietê Park.
In Minas, water with good quality was found in Extrema, at APA Fernão Dias. And in Espírito Santo, water with good quality was also observed in the municipality of Santa Teresa, known as the Capixaba Sanctuary of the Atlantic Forest, which has rich biological environments such as the Saint Lucia and Augusto Ruschi Reserves.
The worst indexes are close to urban centers. Lack of sewage treatment, illegal dumping of industrial effluents, besides deforestation are the main sources of contamination and pollution of water resources.
Advance and retreat in SP
During the month of February, a team of the NGO did 34 collections in different points of 32 subprefeituras of the city of São Paulo. The performance was disastrous: more than half of the samples presented poor quality; 17.5% were regular, and 23.5% were considered of poor quality.
The reversal of this scenario involves the protection of watershed areas, according to the NGO. An example that comes from the city of Salto, in the interior of São Paulo, where the catchment point went from the regular (almost bad), in 2010, to good after a program of three years of forest restoration.
“The solution is not just to collect and treat sewage, it is necessary to raise awareness of the population and good plans,” said Malu Ribeiro, coordinator of the SOS Mata Atlântica Water Network.
Not all rivers have the same fate. The Tamanduateí, which in 2010 outlined a recovery after a series of sewage treatment measures, maintained poor quality after a new wave of irregular occupations, the study said.