What would I do for a cause I believed in? Wear a pin or a t-shirt? Sure, no problem. March in the streets or shiver in a tent, a la Occupy Wall Street? Maybe—if it was something really important.

But what if speaking up endangered my life? What if my fellow activists faced threats, or even actual violence, because of our actions? Would I keep going anyway, or be scared into silence?

Big questions, but those are the kind of things I’ve been asking myself since I met Francisco Pineda last week.

Pineda, an Oxfam America partner and recent winner of the prestigious Goldman Prize, led a citizens’ movement to protect El Salvador’s land and water from the harmful effects of a gold mine. He’s one of six Goldman Prize winners featured in a documentary called The New Environmentalists, narrated by Robert Redford and premiering starting Sunday on PBS stations around the country. “The new environmentalists are making personal sacrifices that most of us can’t even imagine,” says Redford in the trailer, below.

In Pineda’s case, that’s definitely true. Though he comes across in person as an unassuming guy, the story he told when I interviewed him was pretty shocking: A community’s only source of clean water being pumped away by a gold mine. A mining company scientist trying to convince people that cyanide isn’t poison. A leader living with 24-hour police protection because of repeated attempts on his life—and mourning his friends and fellow activists who’ve been killed for speaking out.

Ultimately, Pineda’s grassroots activists won an important victory. They stopped the Pacific Rim gold mine from operating in their region of El Salvador, at least for now. Since then, Pineda has been bringing attention to the effects of oil, gas, and mining projects on poor communities worldwide, and is leading a campaign to stop all mining in El Salvador. “You can live without gold, but you can’t live without water,” he said of the threat to his country’s vital resources.

When I asked Pineda whether he was worried about the risks, he told me he was just doing what he had to do. “This is our responsibility as parents: to protect our land and water for our kids,” he said. “All of us are volunteers, but we’re still ready to give our lives for this.”

In other words, even if the cost is high, some things are always worth fighting for.