The Missouri Department of Natural Resources (MDNR) is developing total nitrogen (TN) and total phosphorus (TP) criteria for streams of the State. Because of varied geology, land-use, and ecological regions across the State, the establishment of blanket criteria for the entire State is unlikely. For example, streams in the Ozarks typically have smaller nutrient levels than other streams in the State, and even streams within the same Ecological Drainage Unit (EDU) may have differing background or baseline TN and TP concentrations. In addition, biologic responses to similar nutrient concentrations are anticipated to differ among and perhaps within various EDUs. An assessment of algal, macroinvertebrate, and fish communities in streams with low-level nutrients found that algal communities correlated well with increasing nutrient levels. Using algal community data to investigate nutrient conditions have been shown to be a successful method in many water-quality monitoring programs.

The U.S. Environmental Protection Agency has recognized that the determination of suitable limits for nutrients for water bodies is a highly complicated issue. It is governed by wide variation in local ecological conditions, as well as the uses placed upon the waters. Too much nutrient loading to a water body can cause rapid growth of algal blooms, organic enrichment and depletion of dissolved oxygen. Too little may result in insufficient enrichment of the aquatic food chain, which would be detrimental to a healthy aquatic biological community. Developing the nutrient criteria that will protect the streams of the state requires significant analysis of water quality data. It also requires input from citizens concerned with the impact of implementation of nutrient criteria.

Nutrient criteria for lakes and reservoirs has already been developed and implemented using the rulemaking process as a part of revision to the Missouri Water Quality Standards. The Proposed 2010 303(d) List of Impaired Waters includes reservoirs placed on the list using Numeric Nutrient Criteria for Lakes. I participated in that rulemaking process attending stakeholder meetings over a 3 year period. Early indications are that the stream criteria will present an even bigger and more complicated process.

Stakeholders have begun meeting for briefings on how criteria development for streams will proceed.  There is still much that is unresolved at this point, including what types of analyses will be applied toward the development of criteria and whether more data will be required.  A technical subcommittee has been organized to address these questions and as soon as an approach to the development of a rule is agreed upon, more meetings with stakeholders will be scheduled. Additional information on nutrient criteria can be found on the DNR website at: 

http://www.dnr.mo.gov/env/wpp/wqstandards/wq_nutrient-criteria.htm

 Quote of the Week

In every glass of water we drink, some of the water has already passed through fishes, trees, bacteria, worms in the soil, and many other organisms, including people...  Living systems cleanse water and make it fit, among other things, for human consumption.
-   Elliot A. Norse, Animal Extinctions