Nutrient Limbo … How Low Can You Go?

“The number is going to be low regardless, so let’s make our best guess and deal with it through implementation.” While most clean water agencies have probably never heard their permit writer utter these exact words, this is the mindset of many regulators. When it comes to dealing with the effects of nutrients, regulators seem to believe that arguing over the exact number, when it is likely to be beyond the limits of technology, is pointless. State water quality criteria managers and permit writers, facing pressure to make progress on nutrients, are struggling to find ways to move forward that are reasonable and scientifically supportable, leading to sometimes contentious battles over what the right number is.   

For more than a decade, NACWA has been urging EPA and the states to develop nutrient criteria and permit limits that are linked to the Clean Water Act uses they are designed to protect. The complex interactions that dictate what effects nutrients have in the water environment, however, combined with variables that can influence those interactions, have led many regulators to throw up their hands in frustration. Developing Clean Water Act criteria for nutrients, especially for flowing waters (e.g., rivers and streams) is difficult, which suggest that perhaps we need a new approach. Is the current Clean Water Act methodology for regulating pollutants simply inappropriate for nutrients, which provide essential ecosystem building blocks when present at the right level?  States and clean water agencies, including work through the Water Environment Research Foundation, have sought new and more effective ways to address the effects of excess nutrients, but more work is needed.

EPA’s ongoing resistance to alternative approaches and insistence that states develop numeric values for nitrogen and phosphorus, will continue to lead to a proliferation of “best guess” criteria. EPA’s typical response when the clean water community raises objections to these best guesses, is that the criteria, whatever the exact numbers, are going to be low—lower than current technology can achieve—so it really does not matter what the exact number is. In other words, clean water agencies will be driven to limits of technology regardless. But here’s the problem—utility managers, especially in areas of the country where nonpoint sources of nutrients dominate, are not comfortable spending hundreds of millions, if not billions, of dollars nationwide on nutrient controls based on a best guess, especially when there is no assurance that water quality will actually improve.   

Yes, the numbers may be low in many instances, but these low numbers combined with the lack of meaningful controls for nonpoint sources, means that clean water agencies are required to take their plants to the limit of technology with no guarantee that improvements in water quality will even be noticeable. Some recent and promising developments regarding nutrient criteria include the use of biological confirmation together with numeric values for nitrogen and phosphorus. More work, however, is desperately needed.  

*Edit: First sentence clarified to say that it is the regulators who believe it is pointless to argue.

This entry was posted in Clean Water, Clean Water Act, Nutrients, Water Quality Standards and tagged , , . Bookmark the permalink.

One Response to Nutrient Limbo … How Low Can You Go?

  1. Thank you for posting this article. If EPA and environmental groups are successful in pushing criteria “past the limits of technology”, those tied in knots will certainly include state regulators but will also include our nation’s agricultural sector. Unreasonable limits on nutrients in water will translate to unreasonable restrictions on fertilizer use, hindering the ability of farmers to produce. There are better ways to address concerns over nutrients in water than establishing fixed limits that are beyond our present ability to achieve and in many cases below background levels in the environment.

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