Like many a successful artist, photographer Vik Muniz could just live the high life, air-kissing his way from gallery openings to auction soirées and then hopping a plane from his Brooklyn studio to his home in Rio de Janeiro.

Muniz has all the trappings of success in the fickle world of contemporary art, but he also has deep ties to Brazil where he was born, 48 years ago, on the working-class fringes of poverty. Tugged by those roots, in 2008 he set about using his art to change the lives of Brazil's most outcast citizens, the garbage pickers, or catadores, who sort and recycle the mountains of trash at Jardim Gramacho, a 321-acre dump outside Rio.

"Waste Land," directed by Lucy Walker, is a deeply touching documentary about his efforts and the people he encounters at the Jardim. A pretty 17-year-old picks trash rather than prostitute herself to support her two kids; an elderly man proud of his literacy has pulled thousands of books from the rubbish and read everything from "The DaVinci Code" to Sun Tzu's "Art of War." The film's central figure is the charismatic Tião Santos, who heads a garbage-worker's collective that pays the workers and agitates for better working conditions.

Befriending the catadores, Muniz pays them to pose. He photographs them, draws their portraits, and projects their images onto the floor of his studio, where the catadores carefully "color" the pictures with discarded bottles, shoes, toilet seats and other junk. Then Muniz photographs the trash collages and launches them into the international art world.

His picture of Santos posed like David's famous 1793 painting " Death of Marat" sold for $50,000 at auction in London. Santos, who attended the auction, wept afterwards saying, "I feel like a pop star." Shown at Rio's Museum of Modern Art, the photos attracted more than 1 million visitors.

Muniz and the filmmakers gave more than $300,000 in auction proceeds and other earnings to the workers' cooperative, which used the money to buy trucks and launch an education program. The film ends with a recap of lives changed.

"Waste Land" is a must-see PBS-style Cinderella story with true grit, a brilliant cast and an improbably big heart.

Mary Abbe • 612-673-4431