EPA Region 10 Mercury Strategy Framework - Environmental ...

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EPA Region 103. Conduct Mercury Deposition ModelingAtmospheric deposition of mercury may be the largestsource of mercury for many watersheds throughoutRegion 10. Understanding the relative contribution ofmercury from the atmosphere, and what the mainatmospheric sources are is important when trying tocontrol mercury in water and fish.Deposition from global sources may be very significant, butbeyond our ability to control. On the other hand, largeemitters in Region 10 may have a very significant effect onlocal deposition, and consequently on concentrations inlocal water and fish.Nationally, the EPA Office of Water has developed amercury deposition model (REMSAD) and a GIS tool(Aggregator) to summarize atmospheric mercury depositionwithin watersheds to help determine the relativecontribution of global vs. regional sources. These tools willsoon be available for states, tribes, and EPA Regions. Theirpurpose is to apportion atmospheric sources of mercury at awatershed scale, primarily for purposes of developingmercury Total Maximum Daily Loads (TMDLs).Mercury Strategy FrameworkEPA role:To use these or more refined models to evaluate sitespecific mercury deposition issues, and provideassistance to states and tribes in using these tools.Different levels of effort ranging from ~ 0.05 to 0.5FTE are described below.1. Basic level of effort: Transfer ArcGIS Aggregatorsource apportionment technology to EPA Region10, including training of GIS staff. Assist states andtribes in using results for TMDLs and air controlstrategies.2. More extensive effort: Above, plus transferREMSAD Hg modeling system to EPA Region 10,and train modeling staff.• Region 10 modeling staff will work with theREMSAD contractor to transfer modelingsystem to EPA computers. These modelingsystems are highly complex and requiresignificant effort to install and operate.• Adjust emissions inputs as needed based on:(a) mitigation scenarios and/or(b) new emissions information and re-runREMSAD.• Pass on new REMSAD results to GIS staff forprocessing with Aggregator tool.3. Highest level of effort: Same level of effort asabove, plus perform additional modeling at a finerhorizontal resolution. Pass on new REMSADresults to GIS staff for processing with Aggregatortool and compare results to coarser resolutionresults.REMSAD model of mercury deposition in Washington, Idaho and Oregon.Mercury Strategy Framework - Page 7
EPA Region 104. Identify / Inventory Mercury SourcesThe relative contribution of Regional sources of mercuryremains unknown. It is crucial to know the magnitude ofdifferent sources and their impact on specific locations inorder to make sure that our work focuses on efforts thathave a high likelihood of success in reducing mercurycontamination.Some EPA programs have or collect information on mercurythat can be used to evaluate potential sources. Theseprograms include: RCRA, CERCLA, NPDES, Air, Miningand TRI. This information is currently scattered among thevarious programs and their separate databases, which makesit difficult to compare potential sources.For example:• Individual project managers in RCRA and Superfundknow whether their specific cleanup projects includemercury as an important contaminant of concern, but wedo not have any way to know the cumulative impact ofsuch sites compared to other sources and pathways suchas air emissions and deposition, sediment erosion andrunoff, or direct discharges to water.• Mercury may be discharged in wastewater from mining,municipal treatment plants, and other facilities underNPDES permits. Although some dischargers monitor formercury, many do not. Even those that do monitor mayhave high detection limits, which do not yield usefuldata.• TRI reports and Air program databases provideinformation on mercury emissions and can be used toidentify sources.Collecting and collating this information from diverseRegional sources will highlight the extent of our knowledgeand of our data gaps related to the relative contribution ofRegional-scale mercury sources.Mercury Strategy FrameworkEPA role:• Solicit and compile information from the Superfundand RCRA programs to describe the scope ofmercury cleanup work in the Region.• The NPDES permits and/or compliance units willprovide information on concentrations of mercuryin permitted outfalls.• TRI data will be reviewed to provide information ofmercury releases to air, land, and water.• EPA’s mining team is beginning an effort tocollaborate with federal land management agencies(USFS and BLM) and Region 10 states and tribesto inventory and prioritize abandoned mines in eachstate or reservation.• All of this information would be compiled into onerepository.GIS layers for fish tissue data will be needed tocompare to potential sources. This may be done inhouseeither by Office of Environmental Assessmentor Office of Research and Development, or under anEPA contract. It may also be supported at the state ortribal level by grant or contract funding; Idaho isalready contemplating a similar project.These are all expected to be relatively straightforwardtasks that would not require a significant investment interms of FTE.Another important part of this work is to conduct statisticalanalysis of existing fish tissue data from waters downstreamof potential sources to determine whether mercuryconcentrations in fish are elevated. Locations where there islittle or no fish tissue data downstream of known sourceareas would also be identified in order to target future fishtissue monitoring.Mercury Strategy Framework - Page 8
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EPA Region 10 Mercury Strategy Framework - Environmental ...

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