São Paulo’s Tietê River’s Polluted Stretch Increases 33 Percent Over Last Year

SÃO PAULO, BRAZIL – The polluted stretch of the Tietê, the longest river in the state of São Paulo, has reached 163 kilometers (km) this year, representing an increase of 33.6 percent compared to last year (122 km), and the water is unsuitable for use. The smallest river length of pollution ever recorded in the survey’s historical series occurred in 2014 when the polluted stretch was 71 km.

The data were compiled by the SOS Mata Atlântica Foundation in the report “Observing Tietê 2019 – The Portrait of Water Quality and the Evolution of Impact Indicators of the Tietê Project”, released on Thursday, September 19th.

On the eve of Tietê Day, celebrated on September 22nd, the study shows that the river’s environmental quality is inappropriate for use, with bad or very bad water quality over these 163 kilometers, corresponding to 28.3 percent of the river monitored by the organization. The monitoring is carried out along 576 kilometers of the river, from the municipality of Salesópolis, at its source, to the downstream Barra Bonita lock, on the Tietê-Paraná Waterway. The largest river in São Paulo crosses the state, extending 1,100 kilometers, from its source to its mouth on the Paraná River, in the municipality of Itapura.

The 163-kilometer pollution spill has spread between the municipalities of Mogi das Cruzes and Cabreúva and another 8-kilometer stretch in the municipality of Salto. Two of the most serious stretches, where the water is deemed very bad, are located near the “Cebolão” highway junction, where the Tietê joins the Pinheiro River – and next to the Penha dam, where the Tietê collects wastewater from the municipality of Guarulhos.

Sanitation

“There are municipalities that are not operated by SABESP [São Paulo State Sanitation Company] that have very low rates of sewage collection and treatment, such as Guarulhos, which has up to six percent of its sewage treated. Mogi [das Cruzes] is also not part of the Tietê clean-up project and is at the head of the river,” said water expert Malu Ribeiro of the SOS Mata Atlântica Foundation.

“Another reason is the increase in deforestation and in areas of irregular occupation in the basin – there are over three million people with no access to sanitation who live in illegal areas, that is, there is no sewage collection service, not even garbage,” she added. Furthermore, the expert stressed the damage caused by pollution from pesticides, fertilizers, pharmacological products, microplastics, oils, and fossil fuel-based greases.

“No matter how much we invest in sewage collection and treatment, our legislation has been increasingly permissive in the use of poisons in agriculture and pharmacological products, for instance. This all ends up in the river, the sewage treatment system does not address it and, with a lower volume of rainfall, there is a concentration of invisible pollutants. All this is concentrated, the river loses its ability to dilute pollutants, and we lose quality”. During the monitored period, rainfall in the Upper and Middle Tietê basins recorded 20 percent lower volumes than the average for the past 23 years, according to data from the foundation.

According to Malu, the last rains in the Greater São Paulo region were laden with burning soot from the Amazon region, in addition to diesel particulate matter. “This shows that the relationship of water quality is no longer linked only to the sewage that the river gets, whether industrial or domestic, it is linked to all these factors occurring in the basin,” she said.

The data were measured at 99 collection points monitored monthly between September 2018 and August 2019. The points analyzed are distributed among 73 rivers in the Upper Tietê, Middle Tietê, Sorocaba and Piracicaba, Capivari and Jundiaí river basins, which cover 102 municipalities in the metropolitan regions of São Paulo, Campinas, and Sorocaba.

Solutions

The study recorded a reduction in the pollution in the metropolitan region around the municipality of Itaquaquecetuba, along a 10-km extension, where the Tietê Ecological Park is located.

“These floodplains protected by the ecological park have served as a climate regulator and have preserved the quality of water. This is a solution: to keep protected areas, to avoid occupation of permanent preservation areas, so that nature can help dilute the pollutants received by the river. Just treating sewage won’t solve the problem,” said Malu.

For the specialist, reversing the bad-to-terrible condition of the Tietê River is possible. “It is possible to reverse this, there is technology for it, to revert to that best rate obtained from the 71 kilometers of pollution, but to do so we need an all-embracing action between all the state and municipal bodies in the Basin, with a focus on land use,” she said. The expert also calls for more restrictive legislation regarding the use of pesticides.

In the remaining 413 kilometers monitored (71.7 percent), the river showed good and average water quality, a classification that permits the use of water for public supply, irrigation for food production, fishing, leisure activities, tourism, navigation and energy generation.

SOS Mata Atlântica emphasized the positive impact of investments in sewage collection and treatment in the basin’s municipalities. According to the foundation, the positive impact was evident in the reduction of the stretch of water considered to be very bad- which in this monitoring cycle stood at 18 kilometers, between the Cebolão, in the junction of the Tietê and Pinheiros rivers, to the municipality of Barueri. In the previous monitoring cycle, the stretch considered very bad had reached 60 kilometers.

“Despite the lack of rainfall, the spot did not extend into the interior of the state. So, this shows that investments in sanitation, even if slow, bring more lasting results. We need these results in all urban rivers. If we hadn’t invested billions in sewage collection and treatment, all of this would be terrible,” she said.

Malu emphasized that the terrible water condition affects people’s quality of life because they breathe on the riverbank.

Tietê Project

Since 1992, SABESP has been developing the Tietê Project, focusing on the expansion of sewage collection and treatment in the metropolitan region of São Paulo.

According to the sanitation company, to date, more than 10 million people have benefited from the collection and treatment of sewage in the region and there have been investments of almost US$3 billion in the project’s works. Currently, SABESP handles the collection and treatment of sewage in 32 municipalities of Greater São Paulo, out of a total of 39.

SABESP expects to collect 92 percent of all sewage by 2025, considering the cities served, and 91 percent of the total sewage collected, in order to expand the sewage treatment services to a further seven million people.

The company has confirmed the extension of the pollution as 163 kilometers currently but said that the sewage collection and treatment work has been contributing to the reduction of the river’s pollution spot, which has shown a trend of historical decline since the 1990s.

“Overall, the reduction in the Tietê pollution spill is approximately 75 percent in the period. In 1992, the blight extended for 530 kilometers along the river, from Mogi das Cruzes to Barra Bonita; today it is 163 kilometers,” the company says.

However, SABESP points out that the depollution of rivers involves much more than sanitation and includes factors such as garbage collection and street sweeping, cleaning of rainwater galleries, land use and occupation control, control of industrial pollution and the society’s environmental awareness.

“This is because the sewage from irregular settlements, the garbage dumped in the streets, animal feces and other waste also ends up in rivers, forming what is called diffuse pollution,” adds SABESP, “which also interferes in water quality.”

Source: Agência Brasil