Pictures: Toxic Foam Chokes Brazil River

Floating Foam

Photograph by Alexandre Carvalho, FotoArena/Getty Images

Heavy metals from industrial runoff give the foam—pictured in Pirapora do Bom Jesus, Brazil, on September 4—its toxicity.

The metals can build up in fish and create physical anomalies, such as extra fins, as well as pose threats to animals or humans that eat them. Likewise, the toxins can damage plants and erode walls and monuments.

Efforts to clean the waterway have led to reduced heavy metal pollution since the late 1990s, Ribeiro said. The river's surface has become cleaner in places, and some fish have returned.

Still, most of the river's pollution today comes from untreated household sewage, such as leftover detergents, soap, and toothpaste, Ribeiro noted.

(Related: "Cocaine, Spices, Hormones Found in Drinking Water.")

Published September 21, 2010

Washing Machine Effect

Photograph by Paulo Whitaker, Reuters

The Tietê River's foamy pollution is especially intense in areas where the river passes through dams, such as in Pirapora do Bom Jesus, pictured on September 2. (See more Brazil pictures.)

A dam's churning waters aerate the river and whip up more foam, Ribeiro said. "It is like turning on a washing machine."

Published September 21, 2010

Sprinkler Solution for Foamy River?

Photograph by Mauricio Lima, AFP/Getty Images

Sprinklers on a bridge in Pirabora do Bom Jesus (pictured in July 2003) are used to reduce the ongoing foam explosions on the Tietê River.

(See "'Wired' Irish River Detects Pollution in Real Time.")

Published September 21, 2010

Bridge Over Troubled Water

Photograph by Alexandre Meneghini, AP

Pirapora do Bom Jesus sanitary workers cross a bridge over the Tietê River in July 2003—a particularly "terrible" year for toxic foam, according to Ribeiro.

In that year "a defect at the dam opened the gates, making a toxic layer of hard metals deposited at the bottom of the river come up" to the surface, she said.

(Related: "Brazilian Water Protection a $100 Million Market?")

Published September 21, 2010

Flying Foam

Photograph by Alexandre Meneghini, AP

The Tietê River's lightweight foam also gets caught in the wind (pictured, windblown bits in July 2003 in Pirapora do Bom Jesus, Brazil).

These flying pieces carry hydrogen sulfide—a waste product common in river pollution—which can irritate people's eyes and respiratory systems.

"When the toxic cloud falls down, it acts like acid rain, damaging plants and monuments," Ribeiro added.

(See "Pollution Can Change Your DNA in Three Days, Study Suggests.")

Published September 21, 2010

Foam Blanket

Photograph by Mauricio Lima, AFP/Getty Images

A child surveys a white blanket of foam on the Tietê River in Pirapora do Bom Jesus, Brazil, in July 2003.

The Tietê—which stretches 715 miles (1,150 kilometers) across the state of São Paulo—has been described as an "open sewer" by scientists at the University of California, Los Angeles.

Published September 21, 2010

Toxic Reflection

Photograph by Helvio Romero, AP

A building in Pirapora do Bom Jesus, Brazil, is reflected in the foam-covered Tietê River on August 30.

Though reducing heavy metal pollution is crucial, the foam problem will only be solved when phosphate and phosphorus are prohibited from the formulas of biodegradable products such as detergent, Ribeiro said.

"Sewage treatment won't solve it," she said. "We would need a new legislation banning these substances, like the ones created in countries such as Canada, Sweden, and Germany."

(Read about responsible cleaning products in Green Guide.)

Published September 21, 2010