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New Study Reveals that Fish Respond Quickly to Reduced Mercury Levels in the Environment


Landmark Research Conducted by Trent Professor Holger Hintelmann to be Published in Prestigious Scientific Journal

Monday, September 17, 2007, Peterborough

Today Trent University Professor Holger Hintelmann and a team of international scientists released the results from their joint U.S.-Canadian study which showed that freshwater fish can recover quickly when mercury levels in the environment are decreased.

The first synthesis of results from the Mercury Experiment to Assess Atmospheric Loading in Canada and the United States (METAALICUS) study will be published in the Proceedings of the Academy of Natural Sciences. This long-term, whole ecosystem experiment, carried out jointly by U.S and Canadian researchers at the Experimental Lakes Area in northwestern Ontario, is an important scientific breakthrough. This is because it shows experimentally that by regulating atmospheric mercury emissions to bring down the amount of the mercury coming back in rainfall, there will be a definite and timely effect on fish mercury concentrations. This has been very difficult to sort out using previously available data.

“This study will enable scientists to make accurate predictions about which lakes will respond more quickly when less mercury is released into the environment,” said Prof. Hintelmann of the Chemistry Department at Trent. “We were able to determine that certain Boreal lakes will improve quickly when mercury from emitters such as coal-fired plants are reduced, but that the Great Lakes will take longer because mercury enters them mostly from the surrounding watershed, not just from precipitation.” The experiment is still ongoing, as scientific data continues to be gathered for other long-term studies.

“We are very pleased to see our work published in such a highly respected scientific journal,” explained Prof. Hintelmann, who began working on this experiment in 1999. “We hope it will receive widespread attention and that its findings will be taken seriously in the designing of new regulations to reduce mercury levels in the environment.”

Mercury has increased greatly in the atmosphere since pre-industrial times as a result of emissions from coal-fired power plants, metal smelting, and other sources. Mercury is persistent in the environment, and is toxic to both humans and wildlife. There are thousands of advisories against eating fish from lakes in both Canada and the U.S.

National and international efforts to regulate mercury emissions are under way, but there is uncertainty about the efficacy of these efforts. One reason for uncertainty is that ecosystems have large amounts of stored mercury from previous emissions. Therefore it wasn’t known how much this stored mercury would contribute to current rates of mercury methylation and bioaccumulation versus the much smaller amounts of mercury coming each year from the atmosphere. For example, at the study site in northwestern Ontario, the soils have over 200 times more mercury stored in the upper five centimeters alone, compared to what rainfall delivers new each year.

The METAALICUS experiment underscores the importance of immediately reducing atmospheric mercury releases. Lowering current levels of direct mercury input to lake surfaces will take only a few years to impact fish mercury concentrations. There will also be additional, slower changes as watershed runoff responds to reduced inputs.
Prof. Hintelmann recently completed his Natural Sciences and Engineering Research Council (NSERC) Industrial Junior Research Chair in environmental modeling and received a Premier’s Research Excellent Award (Ontario). He is internationally recognized as a leader in applying stable mercury isotopes in environmental studies. He developed a variety of methods to analyze environmental samples for their contents of mercury species using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

All of the analysis relating to lake water, food chains and fish for the METALLICUS experiment was conducted in the world-class scientific facilities in the Worsfold Water Quality Centre at Trent University. The Worsfold Water Quality Centre is unique in Canada, and is one of the few water analysis laboratories in the world with the instrumentation suitable for trace metal, trace organic, and major element analysis. The Centre is renowned for providing scientists with the capability of addressing virtually any water quality issue related to contaminants. The Centre currently operates thirteen mass spectrometers and one nuclear magnetic resonance spectrometer, each with unique capabilities for the study of water quality.


For further information, please contact:
Professor Holger Hintelmann, chemistry department, (705) 748-1011, ext. 7659

To facilitate interviews with Trent faculty for expert commentary on water quality and environmental contaminants, please contact Brittany Cadence, Communications Officer, at (705) 748-1011, ext. 6185 or email brittanycadence@trentu.ca.