ET-4D3 (6/24/05)
Chemical Integrity: Proposed Phosphorus Reduction Targets

Table 1.  Proposed Phosphorus Reduction Targets

Target/Source/Indicator Level
Target 1: By 2010, Ohio EPA will adopt nutrient criteria for water quality assessment (Level 1).
Baseline: Excessive nutrients and associated problems, such as reduced dissolved oxygen, growth of noxious plants, and increased turbidity, are a major cause of ambient water quality use impairment. Consequently, USEPA requires that states adopt nutrient criteria into state water quality standard by 2004 or prepare a plan for development of nutrient criteria and demonstrate significant progress in setting nutrient standards consistent with the plan.

Therefore, Ohio has submitted and received USEPA approval for a plan (PDF 41kb) to develop nutrient standards. Specifically, Ohio is currently researching the relationship between nutrient concentrations and periphytic biomass, as measured by chlorophyll a, to determine if there a cause and effect relationship between nutrients and biological criteria. The cause and effect relationship from the nutrient study, if it exists, will be used to both define numeric water quality standards for nutrients, and to develop guidance for how/when to apply numeric criteria should the numeric criteria be exceeded in the absence of biological impairment.

To date, sampling and analysis of results have occurred in three TMDL watershed in rapidly urbanizing MS4 communities.  A summary of project progress is available at OhioProgress2003.pdf (PDF 747kb).

Target 2: By 2010, reduce statewide phosphorus loadings by at least 263,000 lbs/year (Level 3), adequately treat 424,255 gallons/year and adequately store 1.73 M gallons/year of animal waste.

Baseline: The 2010 phosphorus loading reduction target is based on estimates from 2001-2004 319 grant implementation and ODNR Pollution Abatement Cost-Share projects, and what is expected with consistent levels of activity through 2010. Because it is often impossible to do an exact estimate of loading reductions from animal waste treatment/holding facilities, the proxy indicator of gallons/year adequately treated or stored is used instead.

In Ohio, federal, state and local partners are cooperating in a water quality credit trading pilot project to address nutrient loading to the Gulf of Mexico.