'Fingerprinting' method tracks mercury emissions...(e been proposed for construction in Mich...)

"Scientists have models and other ways of estimating how much mercury will be deposited locally, but we may, for the first time, be able to directly differentiate between mercury coming from local plants and mercury that has been transported longer distances."

In a project already underway, Blum's research group hopes to pinpoint which of the many mercury sources in the San Francisco Bay area are contributing most to the contamination of fish and wildlife.

"We don't know whether particular sources of mercury are more biologically available than others and thus more likely to accumulate in animals," Blum said. "If we can figure that out, then we can help local agencies decide where efforts will be most productive in terms of preventing wildlife from being exposed to mercury."

A major influence on Blum's research path into mercury isotopes was Clair Patterson, a famous geochemist on the faculty at Caltech when Blum was a graduate student there. Patterson developed and applied the lead isotopic fingerprinting technique to show the world that unhealthy levels of lead in humans could be traced to lead additives in gasoline. His work ultimately led to the removal of lead from gasoline in the U.S.

"The approach we are taking is similar to what Patterson did with lead isotopes, except the isotopic differences in mercury are about 50 times smaller," Blum said. "If we can do a tenth of what he did, in terms of alerting people to where mercury is coming from and how people are being exposed, I'll be thrilled."

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