ARL News

Mercury Deposition to the Delmarva Peninsula – a Collaboration with NOS


June 9, 2004

The Chesapeake Bay is one of the coastal ecosystems most affected by atmospheric deposition. Atmospheric deposition has been a specialty of the Air Resources Laboratory for more than twenty years. Today, the focus is on airborne nutrients and mercury.

This week, a major intensive study is commencing on the Delmarva Peninsula (to the east of the Chesapeake Bay), to measure and formulate the deposition of airborne mercury to land in the Chesapeake Bay watershed.

Two measurement sites have been set up, one at the NOAA/NOS Oxford (MD) Laboratory, the other at the University of Maryland’s Wye River site. At both locations, ambient air concentrations of total gaseous mercury, particulate mercury, and reactive gaseous mercury are being measured. In addition, measurements are being made of ozone, a wide range of meteorological variables, and the wet deposition of mercury.

Several NOAA groups are involved, including scientists from three ARL groups, and NOS.

It is proposed that the study will last about two months – from the second week in June to the first or second week in August. Analysis of the data will take a considerable effort. A main goal is to use the data to evaluate and/or improve the HYSPLIT-based atmospheric mercury model. Earlier modeling studies suggest that the Chesapeake Bay is receiving much higher than average mercury deposition – with a flux significantly higher than any other receptor (including the Great Lakes, etc.). This is the result of the location of several major sources of atmospheric mercury. One of the world’s largest medical waste incinerators is in Baltimore, and there are a lot of incinerators and coal fired power plants in the local and extended region upwind. Coal combustion is the dominant source of atmospheric mercury.

Bob Wood, Acting Director of the Oxford Laboratory, is leading the overall acivity.

Contact information: Mark Cohen
Phone: (301) 713-0295