White foam from pollution covers the Tietê river in Salto (SP) – 07/06/2023 – Environment

A white foam was registered this Thursday (6) in the stretch of the Tietê river in the city of Salto (75 km from São Paulo). At some points, it is possible to observe that the substance covers the entire river, and it is not possible to observe the natural current of the waters.

The phenomenon is not completely new. In July 2022, the same white foam was reported covering the river in the Salto region as well. At that point, it was the fourth time the material had been viewed over the previous ten months.

Frequent in the part of the river that crosses Salto, environmentalists have already explained that the foam is normally seen after a prolonged drought. The training takes place from waste materials thrown into Tietê.

In a note, the city hall said that the foam is caused by pollution from the metropolitan region of São Paulo. “Salto treats almost 100% of the sewage, but, like all cities in the middle Tietê, it receives the river in terrible conditions.”

The municipality also reported that at this time of year, when there is less rain, foam formation is more common. This makes sense because the river is less full, causing pollutants such as detergents to be more concentrated in the water. “It is a serious problem that has been dragging on for several years”, completes the note.

The report also contacted Cetesb (Environmental Company of the State of São Paulo), but had no response until the publication of the text. Previously, the entity had already informed that foam was more common in the Salto region due to the low water flow and the presence of untreated domestic sewage.

The problem could be solved with the implementation of adequate sanitary sewage systems, including the collection, removal, treatment and final disposal of domestic sewage. Rains could also prevent foam composition.

Pollution in Tietê is still a problem faced by the state of São Paulo. Since 1992, the Tietê Project has been implemented with an investment of at least US$ 3.4 billion (about R$ 18 billion, at current exchange rates) since then. Although it still has many pollution problems, there have been some advances.

One of them was the pollution spot in the river. In the 1990s, the length was more than 500 km. In 2021, the index dropped to about 85 km. A year later, in 2022, it rose 43%, reaching 122 km of polluted area in the river’s body of water.

Stretching 1,100 km, the Tietê crosses the state of São Paulo — it starts in Salesópolis and, running in the opposite direction of Serra do Mar, goes to Itapura, where it empties into the Paraná River.