for National Geographic News
Sometimes it's good to have bugs in your water.
An increase in the diversity and size of water insects is heralding an improvement in the environmental quality of streams that flow into the Carson River in northern California and Nevada.
The streams run below an abandoned sulfur mine high in the Sierra Nevada mountain range that runs along the border between the two states (California map).
For decades a toxic soup of acids and heavy metals leaked from the mine, coloring the water and rendering the streams nearly lifeless.
In 2000 the U.S. Environmental Protection Agency (EPA) designated the mine as a Superfund site, one of the most polluted spots in the United States.
"The water quality was awful," said Kevin Mayer, the EPA project manager for the mine cleanup.
"And unlike most sites where I work, where groundwater and soil contamination can't be visibly seen, it was extraordinarily disheartening to see the bright orange streams going down miles away from the mine."
But since then cleanup activities have led to a "dramatic improvement" in the streams' habitats, said David Herbst, a biologist with the Sierra Nevada Aquatic Research Laboratory in California.
Herbst studies insects to monitor stream health throughout the Sierra Nevada region, including the waterways downstream from the sulfur mine.
Some waters still have an orange tinge and contain toxic metals, but his monitoring results indicate the return of algae, insects, and fish to the watershed.
Insects and Health
Insects and other invertebrates are central to stream life, Herbst said by email.
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