A river’s return from the brink of disaster

In one long-polluted Ozark river, the little fish darting through the water and the rare mussels hiding on the pebbly bottom tell a story worth celebrating. They’re signs that the Spring River is benefitting from environmental cleanups after a century of mining pollution. A professor and his students are uncovering the evidence of recovery. But there’s a twist: They’ve also found a new environmental challenge unfolding farther upstream.