By Brent Fewell
The following may be a wee bit granular for some of my readers, but hear me out, because this is a big deal in the context of improving national water quality. According to EPA, nearly 50 percent of the Nation’s water bodies, i.e., lakes, streams, rivers, still do not meet water quality standards due to impairments from pollution. One of the biggest offenders is excess nutrients as I’ve touched upon previously here (think harmful algal blooms). Thus, EPA has been applying significant pressure on the States to adopt numeric nutrient criteria (as opposed to qualitative criteria), which in theory should make it easier and more effective to regulate nutrient pollution. This has been a highly contentious issue, even going back to my time at EPA, as reflected in the recent Florida litigation.
The states have pushed back on EPA for a number of reasons, the first being, numeric criteria are scientifically difficult to get right, secondly, they are costly to develop and implement, and thirdly, they may not actually restore the water body. While numeric critera are important, they must be linked to restoring the biotic communities in the impaired waters, i.e., true environmental restoration will not occur unless the aquatic communities and critters are restored. However, excess nutrients may not be the only factor impairing a stream’s biotic community. Stressors such as stream temperature, heavy flows, sediments, and other toxic contaminants can and often will impede biotic integrity. My former Duke professor, Ken Reckhow, one of the Nation’s leading water quality scientists, discusses this very point over on his blog.