EPA Impaired Waters Listing May Open Door To Mississippi Nutrient Limits

By Inside EPA
23 August 2011

EPA is poised to decide in the coming weeks whether to list coastal waters in Louisiana as impaired for dissolved oxygen (DO), a decision that environmentalists hope could begin a regulatory process to restrict nutrients in upstream Mississippi River Basin waters even though the agency recently denied activists’ petition to require such limits. But environmentalists are also pushing EPA to give a higher priority ranking to the waters, which would require actions more quickly to address the pollution, as well as arguing for EPA to list the coastal waters as impaired for nutrients, which would more directly address the source of the impairment and is consistent with Science Advisory Board advice. The agency earlier this year sent a letter to the Louisiana Department of Environmental Quality (LDEQ) disapproving of the state’s "decision not to list three coastal waters west of the Mississippi River mouth which are affected by low levels of dissolved oxygen."

While LDEQ found that the three coastal segments were not meeting dissolved oxygen criteria, the state designated the waters as category 4b, a classification for waters that are impaired but for which pollution limits, known as a total maximum daily load (TMDL), is not needed because other controls will lead to meeting water quality standards. "EPA agrees with LDEQ’s decision that the three coastal segments . . . are not meeting the applicable marine dissolved oxygen criteria. However, EPA disagrees with the State’s decision that these water quality limited segments are exempt from the TMDL process.

"Consequently, EPA insists that the agency add the segments to the state’s Clean Water Act (CWA) section 303(d) impaired waters listing, meaning that a TMDL would be required. The agency also assigned the waters "priority ranking," environmentalists note, though they argue it is not high enough.EPA is now considering comments and hopes by the end of the month to finalize its decision in the Federal Register, according to an EPA source. Under section 305(b) of the Clean Water Act (CWA), states are required to assess the water quality status of waterbodies within their boundaries. EPA encourages states to use a five category system to classify which waters are meeting water quality standards. Those waters that are not meeting the standards are listed as being impaired, as required by CWA section 303(d), and can then be subject to control requirements, such as TMDLs.

Sources say that should EPA finalize its decision to list the waters as impaired, it could act as a hook to regulate upstream waters that may be contributing to the impairment, beginning the process of cutting down on nutrient pollution in the Mississippi Basin that contributes to the large hypoxic Dead Zone in the Gulf of Mexico. Low levels of DO can be a function of high nutrient levels, because the nutrients encourage eutrophication. For example, one activist says that listing the waters as impaired under 303(d) would require a TMDL, which will set a cap on pollution in the Gulf that could target upstream sources of pollution, "given the fact that the majority of the sources

[of impairment] are not in Louisiana. I’m not saying it would be an easy process," the source says, but notes that "loadings would have to be allocated outside of Louisiana."

‘Solve The Problem

Another environmentalist says EPA’s efforts are a "positive action . . . recognizing the problem in coastal waters," and the result will be water quality criteria that "will ultimately drive the actions necessary to solve the problem." "I think once you develop a TMDL for the coastal waters, then the solution for addressing TMDLs certainly crosses state boundaries and moves upstream," the source says. "And that might be the catalyst for more interstate cooperation for solving" the Gulf hypoxia problem. "And the criteria can also be a hook for voluntary options," the source says, like nutrient trading programs. "So it’s not like people are looking at it as a totally regulatory approach to things. I think most people realize there’s going to be a need for a voluntary and regulatory approach." Calls for such options could provide environmentalists with another means of regulating nutrients in the Mississippi River after EPA recently denied their petition seeking such regulations. Agency officials said granting the petition would impose burdens, while encouraging states to develop their own limits would be a better use of agency resources. But agency officials also left the door open to such regulations.

And agency officials have also contracted with a private firm to develop a model to help determine nutrient concentrations in the Mississippi River basin that are contributing to low levels of DO. Environmentalists have welcomed the modeling saying it could help states establish the “right targets for their own tributaries to the Mississippi, and for EPA to act if the states fail to do so.” But it is unclear whether EPA will agree to regulatory requirements anytime soon. The agency told LDEQ in its April 6 letter that while "nutrient load reductions may be needed from all States in the Mississippi River basin to reduce the size of the Gulf hypoxic zone and restore Louisiana coastal waters to full attainment of applicable water quality standards," the agency saw opportunities to address the problem by "large-scale reintroductions of the Mississippi River and beneficial use of dredged material, [which] provide excellent opportunities to both restore Louisiana’s vanishing wetlands and reduce the nutrient load flowing directly into the Gulf of Mexico."


EPA Weighs Comments

EPA is now weighing comments from environmentalists and the state on its proposal to list the waters as impaired, many of which focused on the appropriate category of impairment. The state planned to list the waters separately under the category 4b designation rather than so-called 303(d) list. LDEQ in its May 13 comments holds that the segments should be listed under section 4b because the actions described in the federal 2008 Gulf Hypoxia Action Plan will address the impairment and only a small percentage of nutrients in the Mississippi River are from Louisiana. But environmentalists and their supporters are opposing the state’s approach, with the Tulane University Law Clinic in its May 13 comments arguing that the action plan is voluntary, does not have adequate funding to meet its own goals and fails in numerous ways to qualify as a required control. — Erica Martinson emartinson@iwpnews.com