UMN Expert: The public health risks of nitrate in drinking water

Kara Nell

A recent study published in the journal Environmental Research found links between nitrate exposure from drinking water and increased cancer risk. On Monday, the Minnesota Department of Agriculture implemented rules to reduce the impact of nitrate on groundwater in parts of the state. 
Kara Nell, an assistant professor of chemistry at the University of Minnesota Morris, is available to comment on the potential health risks associated with nitrates, water-quality safety standards and her work to make Minnesota’s drinking water safer.

Kara Nell, Ph.D.
The risks posed by nitrates

The main concern has always been with infants taking in too much nitrate. If an infant takes in too much, it can impair the red blood cells’ ability to bind oxygen and cause them to suffocate because they don’t have enough oxygen flowing through their body. It can be fatal in some instances. This is why the Environmental Protection Agency (EPA) requires that our drinking water contains 10 parts per million (ppm) of nitrate or less.

What the new study tells us
What this finding says is that, as has been speculated, nitrates could be carcinogenic and result in adverse birth outcomes below 10 ppm. They could be linked to low birth weight, preterm birth and neural tube defects. The researchers examined data from across the United States and found a correlation between certain types of cancer and nitrates. This is the first time the correlation has been quantified.

Current and future water-quality safety standards
We’re just beginning to figure out the health effects of nitrate exposure. The unfortunate thing in toxicology is that almost all chemicals are innocent until proven guilty, unless they’re used in foods or drugs. Maybe in ten years we’ll have more data and know more, but the bottom line is that it's better to be safe than to worry about it. As long as you’re filtering your water through something, that’ll make it a lot better.

Making drinking water safer
Don’t be scared of your tap water! You can make your drinking water safe rather than buying bottled water, which can contain plasticizers and possible endocrine disruptors. Just make sure you filter it and change your filter on a regular basis.

Working to improve drinking water quality
I design and make materials to remove nitrates from water. I’m currently in the process of designing a material that binds nitrate over other natural ions in our water. If we can take out just the nitrate, then we’d be able to use the material for much longer than something that would also bind chloride or other ions.

Kara Nell holds a Ph.D. in chemistry from the University of Oregon and a B.A. in chemistry from Albion College. She completed postdoctoral research at the Lawrence Berkeley National Laboratory. Her areas of expertise include environmental and material chemistry. 

Jenna Ray
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