Major nitrogen sources in U.S. waterways

Domestic sewage and industrial wastewater require treatment to reduce the concentration of nitrogen and phosphorus pollution deposited into rivers, streams, and lakes. Wastewater treatment plants have reduced their load by optimizing equipment, upgrading treatment facilities, and implementing watershed-based approaches. Nitrogen from agriulture, however, remain high.

Total nitrogen load (kg) delivered from farms and wastewater in Gulf Hypoxia Task Force states, plus Texas, based on data collected between 1999 and 2014. Scientists used computer models to estimate how nitrogen traveled through rivers and streams, with 2012 as the reference year.
Chart: Jennifer Bamberg and Lauren Cross, Investigate MidwestSource: U.S. Geological SurveyGet the dataEmbed Created with Datawrapper