Almost 20 Percent of Americans Are Drinking Nitrate Contaminated Water

In the early 20th century, scientists discovered how to produce nitrate from air. This was key to the development of factory farming because nitrate is a very efficient fertilizer that is readily absorbed by crops. But the following decades revealed significant downsides to the use of nitrogen-based fertilizers. Because the compounds in fertilizer can make their way into soil, groundwater and nearby waterways, nitrogen-based fertilizers have emerged as the main source of nitrate contamination in drinking water.

Now, a new report from the Environmental Working Group (EWG) finds that around 18% of the United States population relies on drinking water with elevated nitrate levels in drinking water, which the EWG defines as levels above 3 mg/L.

Nitrate is a naturally occurring compound that exists in plants, rainwater and groundwater. However, the rise of industrial agriculture after World War II has accelerated nitrate contamination in the environment to levels far beyond those found naturally in the nitrogen cycle. And that’s a problem, because high levels of nitrate have been linked to increased risk of cancer, birth defects and thyroid disease.