Nitrogen isotopes show how nutrients leach out of septic tanks and into pond ecosystems.
Sediment core from a Copenhagen lake tells the story of the Industrial Revolution.
Tornadoes and flash floods can happen at the same time, but safety instructions for each one is the opposite.
Mass migration to Chinese cities has likely decreased the total number of premature deaths caused by air pollution.
Hundreds of U.S. streams may have significant levels of endocrine-disrupting chemicals from treated wastewater.