One-third of all Pennsylvania waterways are polluted enough to harm wildlife, recreation, or drinking water, a new federally mandated report concludes.

The report by Pennsylvania's Department of Environmental Protection found 27,886 miles of streams statewide were impaired in one or more ways. Most are in Philadelphia and surrounding counties. 

The Inquirer reports nearly 97% of streams in heavily urbanized Philadelphia are labeled impaired, the highest rate of any county in the state. Delaware County and Lancaster County round out the top three. 

Read the full report here. Comments can be submitted here until March 1.

THE CONTEXT: According to The Inquirer, the sources of the pollutants vary, but the top three culprits are storm-water runoff, agricultural runoff, and acid-mine drainage, which occurs when water flows over sulfur-bearing materials.

President Joe Biden's Infrastructure Investment and Jobs Act promises billions to clean up old mines that leach such waste. But some environmental advocates warn the real cleanup costs are likely to be higher than expected given some sites are missing from a federal inventory.

In agrarian corners of Lancaster County, meanwhile, farm runoff is polluting waterways and the connected and ecologically vital Chesapeake Bay. (In short, fertilizer discharges will supercharge algae growth, which kills fish.) 

After years of pressure to improve its cleanup process, Pennsylvania has submitted an updated strategy to meet 2025 pollution reduction goals for the Chesapeake Bay — but progress has stalled on this front before.