RD238 - Status of the Virginia Mercury Study


Executive Summary:
This report is prepared pursuant to the requirements of Chapter 867 of the 2006 Acts of Assembly (House Bill 1055). The Act directs the Department of Environmental Quality (DEQ) to conduct a detailed assessment of mercury deposition in Virginia in order to determine whether particular circumstances exist that justify, from a health and cost and benefit perspective, requiring additional steps to be taken to control mercury emissions within Virginia. The assessment must include (i) an evaluation of the state of mercury control technology for coal-fired boilers, including the technical and economic feasibility of such technology and (ii) an assessment of the mercury reductions and benefits expected to be achieved by the implementation of the CAIR and CAMR regulations. This report is a preliminary assessment of DEQ’s efforts and findings. A final assessment will be provided by October 15, 2008.

DEQ identified the largest emitters of mercury in the Commonwealth and in August 2006 sent letters to 75 industrial facilities in Virginia requesting estimated mercury emissions for calendar years 2002 and 2005. The facilities chosen for this request are the largest known mercury emitters in Virginia. Information received from each of the facilities will be used to estimate future-year emissions. The future-year estimates will be used in the air quality modeling and deposition analysis.

In order to assess the mercury reductions and benefits expected to be achieved by the implementation of the Clean Air Interstate Rule (CAIR) and the Clean Air Mercury Rule (CAMR) regulations, DEQ staff issued a Request for Proposal (RFP) on September 25, 2006 for a detailed assessment of mercury deposition in Virginia. The scope of the RFP included an analysis of mercury air emissions data, an assessment of mercury deposition modeling, as well as the development of information on the human health risks from consuming methylmercury-contaminated fish.

In February 2007, two contracts were awarded for the assessment. One contract was awarded to ICF Resources, LLC (ICF) for work on the mercury emissions data analysis and deposition modeling portions of the study. Specifically, ICF will conduct mercury deposition model simulations that can be used by DEQ to examine:

1. Air deposition as a contributor of mercury to Virginia’s impaired water bodies and other mercury sensitive waters;

2. Impacts of emissions from Virginia’s electric generating units (EGUs) on mercury deposition in Virginia, including an evaluation of the benefits of CAMR and other federal and state programs which may impact or reduce mercury emissions;

3. Contributions of Virginia’s non-EGUs to mercury deposition in Virginia; and

4. The individual impact of a selected number of Virginia facilities to local and regional scale mercury deposition.

DEQ also awarded a contract to the Center for Environmental Studies at the Virginia Commonwealth University (VCU) to assess the human health risks from consuming methylmercury-contaminated fish. The study will focus on understanding the risks of consuming methylmercury through ingestion of freshwater fish by sensitive sub-populations (such as children and pregnant women) in Virginia. This study will use DEQ’s fish tissue database and on-site fish consumption data to estimate risks to human health. These estimates of risks to human health will then be monetized by DEQ to arrive at potential economic benefits and costs of current levels of mercury and potential future reductions. The mercury uptake and human health risk portions of the study are dependent on the findings in the mercury deposition portion of the study. Final results from the modeling deposition portion of the study are scheduled to be completed by mid-February 2008. Therefore, the main focus of this interim report is the work completed to date on ICF’s emissions data analysis.

DEQ was unable to fund an analysis of the mercury deposition impact on fish tissue concentrations resulting from Virginia sources because the only vendor who met the requirements of the RFP was cost prohibitive. Therefore DEQ staff will consult available literature sources, review experiences in other states, and interact with researchers to derive a default value or range of values to estimate the effects that changes of deposition rates of mercury to watersheds could have on local fish tissue contamination levels.

DEQ is in the initial stages of performing the mercury control technology cost assessment task. The project team is collecting data from internal and external sources on control technologies used at all of Virginia’s coal-fired power plants in order to understand expected mercury removal rates and costs of controls. The team expects to develop estimates later this year that distinguish the portion of such control costs that can be ascribed to mercury from the co-benefits of controlling other pollutants. The team then will analyze the costs associated with mercury-specific control technologies for coal-fired power plants.

Information regarding the Virginia Mercury Study can be found on the DEQ website at http://www.deq.virginia.gov/air/vamercury/vamercurystudy.html. Additionally, the State Air Pollution Control Board and DEQ are hosting a symposium about mercury on November 28-29, 2007 in Newport News, Virginia. Interim results of the DEQ mercury study will be presented at the symposium. Outside experts and stakeholders have been invited to provide information and perspectives on mercury emissions; transport, deposition, and biotransformation; prevention and control technologies; and human health and environmental impacts.