Chesapeake Bay Program Voluntary Volume 1, Issue 1 Zones Phaseout August 2001 What did we commit to? The Governors of MD, VA, and PA, the EPA Administrator, the Administrator of the Chesapeake Bay Commission and the Mayor of District of Columbia endorse voluntary phaseout of mixing zones for persistent or bioaccumulative toxics in Chesapeake Bay Watershed. By signing both the Chesapeake Bay Agreement and the Toxics 2000 Strategy, the signatories are asking that point sources in the Chesapeake Bay Watershed commit to the following commitments: Zero Release Objective: To achieve the following Chesapeake 2000 Bay Agreement commitment "Through continual improvement of pollution prevention measures and other voluntary means, strive for zero release of chemical contaminants from point sources, including air sources. Particular emphasis shall be placed on achieving, by 2010, elimination of mixing zones for persistent or bioaccumulative toxics. What are mixing zones? A mixing zone is an area where pollutants from a point source's discharge pipe are mixed with receiving waters to dilute the pollutant's concentration. Inside a mixing zone, discharges of the pollutant are allowed to exceed the water quality limits set by a state. It is assumed that the brief exceedance of the water quality standard will not significantly impact aquatic organisms. At the boundary of the mixing zone, the concentration of the chemical must meet the water quality standard set for that particular body of water. The size of mixing zones is site specific and may vary. How a mixing zone is determined? Mixing zones are a legal regulatory option a point source can choose to comply with water quality standards. Mixing zones are site specific, scientifically based, developed according to applicable rules, regulations and policies and undergo rigorous regulatory review prior to issuance of a National Pollution Discharge Elimination System (NPDES) permit by the states and EPA. In order to issue a NPDES permit with a mixing zone, the permitting authority has determined that 1) the mixing zone would not cause impairment of the receiving water, 2) There is no lethality to organisms passing through the mixing zone and 3) there are no significant health risks, considering likely pathways of exposure. A NPDES permit is issued in accordance with the administrative process act (APA) of the NPDES authority. How will we do it? To accomplish this objective, the signatories commit to: Mixing Zone Phase Out Strive to meet water quality standards for persistent or bioaccumulative chemical contaminants at the point of discharge through continual improvement of pollution prevention measures and other voluntary means. • By 2001, establish a baseline for the facilities not meeting water quality standards at the point of discharge for persistent or bioaccumulative chemical contaminants and by 2003 and 2007 report on their progress in reducing concentrations at the point of discharge in order to eliminate mixing zones. • An initial emphasis shall be placed on phasing out mixing zones for persistent or bioaccumulative chemical contaminants in the following areas: Regions of Concern, Areas of Emphasis, - 303(d) listed waters for persistent or bioaccumulative chemical contaminants, - Areas under finfish or shellfish advisories caused by persistent or bioaccumulative chemical - contaminants. i Emphasis is placed on voluntary pollution prevention Measures to achieve this goal. Continued on page 2 Point source facility What is a mixing zone? Concentration of contaminant briefly exceeds water quality standard within the mixing zone At the Edge of mixing zone the concentration of the contaminant meets the water quality standard ------- Why would a point source have a mixing zone? Regulatory agencies have long recognized that the potential toxicity of an effluent will tend to decrease as it mixes with the receiving water body, simply due to dilution. Certain regulatory procedures have evolved to account for this tendency. These procedures result in less stringent permit effluent limitations compared to the limits that would be applied if dilution was ignored. In theory these procedures can be used to develop less stringent limits without compromising enviromnental protection. Concerns have arisen that this practice of recognizing a "mixing zone" may not be sufficiently protective in all cases, e.g. where sediment contamination may be an issue. While there are often significant costs that a discharger must bear when mixing zones are eliminated, it may be difficult to directly identify a specific enviromnental improvement that would be associated with the elimination of a particular mixing zone. Nonetheless, the Chesapeake Bay Program has determined that the concerns about the reduced level of protection associated with applying mixing zones are sufficiently high that dischargers should be encouraged to eliminate them whenever feasible, on a voluntary basis. Why phaseout mixing zones? A voluntary mixing zone phase out is one step toward achieving the "zero release" goal that industries have agreed to in the Chesapeake 2000 Agreement. impaired. By 2010, we are asking point sources to voluntarily eliminate all mixing zones for these contaminants throughout the watershed. In addition there are other benefits and reasons: Reduced acute and chronic water quality impacts Eliminating mixing zones will result in the reduced potential for acute and chronic impacts to aquatic resources from persistent or bioaccumulative toxics briefly exceeding water quality standards in the actual mixing zone. An elimination of mixing zones will also result in a reduction of mass loading to the ecosystem, especially to the sediment habitat, and a reduced potential long term bioaccumulative impacts from that facility. Bioaccumulative impacts from mercury and PCBs can be seen in the fish advisories which exist in many parts of the Bay for these substances, and in EPA's issuance of a nationwide advisory for freshwater fish containing mercury. Cont'd on column 2 Continued from column 1 Reduced loadings to sediment The 1999 Chesapeake Bay Basinwide Toxics Loading Inventory indicates that anywhere from 60-90% of metals such as copper and mercury are trapped in the tidal river sediments and not flushed out of the tidal rivers. The 1999 Toxics Characterization report indicates that in some Chesapeake Bay tidal rivers the concentrations of metals, pesticides, PAHs, and PCBs are elevated to levels that indicate probable adverse effects to aquatic resources. At these levels, these chemical contaminants may be bioavailable and impacting living resources. A voluntary phaseout of mixing zones is one step to reduce net loadings to the Chesapeake Bay sediments of metals and other persistent chemical contaminants. Limitations of the Mixing Zone designation There are also examples of shortcomings in the design of a mixing zone. One, mixing zones that have been established in State's permitting policies have still resulted in unintended benthic degradation in the mixing zone. Second, the design may not consider the cumulative load and effect from multiple sources of different contaminants within a mixing zone. Third, mixing zones may be subjected to extreme tide or enviromnental conditions, when these events occur violations of the water quality standard outside of the mixing zone edge may occur at no fault to the facility, but rather due to a limitation in the hydrological design of the mixing zone. For these and other reasons, the Bay Program urges a voluntary phaseout of mixing zones for persistent or bioaccumulative toxics. Benefits to the Facility Recognition for committing to voluntary phaseout: - Press for committing to voluntary phaseout - Potential pollution prevention awards and public exposure for enviromnental stewardship - Potential regulatory incentives What chemicals will we focus on? EPA's Great Lakes regulatory Mixing Zone phase out focuses on bioaccumulative chemicals of concern (BCC). The Chesapeake Bay Program will focus on some of the chemicals on the BCC list, but not others because these contaminants are not being released by point sources in the Chesapeake Bay Watershed, although some of these "legacy contaminants" appear to be impacting living resources from other sources. Due to the State impaired water list and the Toxics Characterization report this phaseout will also focus on metals. Data indicate these persistent toxics are potentially impacting aquatic living resources in the Chesapeake Bay tidal waters. Cont'd on page 3, column 1 ------- Cont'd from page 2, column 2 The final consensus based list for the voluntary phaseout of persistent or bioaccumulative toxics is under development. Additionally, an effort is underway to prioritise the chemicals to focus the phaseout. A preliminary very draft list of focus chemicals is: mercury and its compounds, lead and its compounds, chromium, copper, arsenic, cadmium, nickel, zinc, PAHs, PCBs, hexachlorobenzene, dioxins and furans, and octachlorostyrene. Where we will focus efforts? The Chesapeake Bay Agreement goal commits the Bay Program to voluntarily phase out mixing zones for persistent or bioaccumulative toxics throughout the Chesapeake Bay Watershed. In the Toxics 2000 Strategy, it is further clarified by the Chesapeake Executive Council to initially focus on point sources with mixing zones for persistent or bioaccumulative toxics located in the watersheds of the Regions of Concern, the Areas of Emphasis, watersheds with a fish consumption advisory or watersheds listed as being impaired (on the 303 (d) list for each state). What is our early implementation strategy? A voluntary strategy to guide progress... The Bay Program, (EPA, state agencies, pollution prevention programs, enviromnental groups, publicly owned treatment works operators, and industry representatives), is working to identify areas to focus collective efforts of the Bay Program to achieve this commitment over the next ten years. The strategy contains the following focus areas: - Establishing a baseline of facilities - Education and outreach - Identify technological needs - Recognition and incentives - One on one targeting What is EPA's Policy Stance on the National Mixing Zone Regulation? Currently, the Administration is not proposing a regulatory phaseout of mixing zones. They are currently evaluating standards and criteria and it appears that mixing zones will not be an issue or area for regulatory change. Other EPA initiatives related to the voluntary phaseout: EPA's PBT (persistent bioaccumulative toxics) intiative outlines a strategy to help reduce these contaminants from the enviromnent as well as monitoring initiatives. Our effort should seek to coordinate with these initiatives. Cont'd on column 2 How do TMDLs affect this voluntary initiative? Total Maximum Daily Loads may require point source facilities to comply with stricter than water quality standards. The voluntary mixing zone phaseout may be one step for industries to get ahead of a proposed TMDL. However, this will be evaluated on a case by case basis. How will the State/Bay Program permitting offices handle new and renewal applications for mixing zones? It will be the jurisdictions policy to actively explore and encourage non-mixing zone options to new and renewal permit applications to mixing zones. For More Information Contact: Bob Steidel Chair of the Point Source Workgroup Hopewell Regional Wastewater Treatment Facility 804-541-2210 bsteidel(®,hrwtf.org Bob Dunn Chair of the Pollution Prevention Workgroup DuPont 804-383-3895 Robert .L. Dunn(S?U SA. dupont. com Allison Wiedeman, Technologies Coordinator Chesapeake Bay Program Office 410-267-5733 ' wiedeman.allison@epa.gov Darin Crew, Toxics Fellow Chesapeake Research Consortium 410-267-9860 crew.darin@epa.gov 1 The Toxics 2000 Strategy and other reports and information on mixing zones, chemical contaminants and the Bay Program can be obtained at: www.chesapeakebay.net ------- |