Annual Meeting Features Mercury Expert

Steven E. Lindberg, Ph.D. is a Corporate Fellow Emeritus of the Oak Ridge National Laboratory. His presentation to the ICIE Membership on November 25, 2008, Mercury – from the Geosphere to the Biosphere and Back Again, posed the question “once the genie is out of the bottle, is it too late?”

Right now, Dr. Lindberg noted there is a lot of mercury in circulation – which he referred to as the “Billion Dollar Dilemma,” referring to the industry estimated expense it would cost to develop technology to address this.

Dr. Lindberg noted the following about mercury:
• It has a complex cycle
• It doesn’t stay put
• There is a great deal of redox chemistry
• Hotspots can be a red herring
• Natural sources large & not regulated
• Actions require multimedia perspective
• Expensive actions are sometimes ineffectual
• Legacy Hg is a consideration (atmosphere not only pathway)
• We probably know more about sources than sinks
• The methylation of mercury (the way in which it is absorbed) is influenced by lake characteristics

Therefore, Dr. Lindberg noted there is no simple solution to this dilemma. But, he said, there is also no good reason to emit mercury if it can be avoided, or if it can be captured with reasonable control technology.

Dr. Lindberg contrasted the mercury dilemma with the issues we had in the 1960’s with lead in gasoline. In the 60’s we took lead out of gasoline and directly addressed the problem.

The problem with mercury is its complicated cycle. With mercury there are lots of reactions going on – from mercury in the air turning into mercury in the rain, many of these have never been measured in the lab, but just estimated, then put with a comprehensive ecosystem model. Where does mercury go and how does it behave once it gets there? The fact is that we don’t know exactly.

Dr. Lindberg noted there are two sources of mercury in the air:
• Anthropogenic Emissions to air are globally distributed
• Geologic Emissions are also globally distributed

With that in mind, how much of the deposition of mercury is from US sources in the US? In the West, 80 to 90 percent of mercury is from sources outside of the US, and that percentage (of non US sources that make up the whole) goes down the further east you go.

Minnesota and Florida are the two states that are furthest along in understanding total maximum daily load of mercury, and therefore understanding the changes they can make that can help that system respond. Of the options presented by Hayes and the ICL, Dr. Lindberg couldn’t be sure.