ET-4E3 (6/24/05 version)
Chemical Integrity: Proposed Nitrogen Reduction Targets

Table 1. Proposed Nitrogen Reduction Targets

Target/Source/Indicator Level
Target 1: By 2010, 20% reduction in the number of public water systems with nitrate MCL violations (Level 4).
Baseline (July 2004): During the past 5 years, 13 public water systems using surface water sources and 34 public water systems using ground water sources has nitrate MCL violations.
Target 2: By 2010, statewide nitrogen loading reduction of 754,000 lbs/year, adequately treat 424,255 gallons/year and adequately store 1.73 M gallons/year of animal waste (Level 3).
Baseline (July 2004): 319 grant implementation projects currently reduce nitrogen loads by an estimated 623,000 lbs/year in the Ohio River basin and 125,000 lbs/year in the Lake Erie basin; ODNR, Division of Soil & Water Conservation Pollution Abatement projects currently reduce nitrogen loads by an estimated 4,000 lbs/year in the Ohio River basin and 500 lbs/year in the Lake Erie Basin. 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.
Target 3: 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 is 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 has occurred in three TMDL watersheds in rapidly urbanizing MS4 communities. A summary of project progress is available at OhioProgress2003.pdf (PDF 747kb).

Target 4: By 2015, reduce Gulf Coast hypoxic zone to less than 1,930 square miles through a 30 percent reduction in nitrogen discharges to the Gulf (Level 3).

Baseline: From 1996-2000, the average size of the hypoxic zone in the Gulf of Mexico off Louisiana and Texas was 5,454 square miles. About 90 percent of the nitrates entering the Gulf come from runoff. About 56 percent of the nitrates enter the Mississippi River above the Ohio River. The Ohio River Basin adds 34%.

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.

Target 5: By 2006, the Ohio EPA Integrated Water Quality Monitoring and Assessment Report will include data about surface drinking water sources with seasonal exceedances of nitrate MCLs (Level 1).
Baseline: Ohio surface water quality standards use the SDWA MCL for the public water supply.