february 19, 2005. usgs, 2000 usgs, 1997 * “new approaches are necessary to better elucidate,...

*Mercury in the Salt Lake Valley

* It’s kind of a big deal

February 19, 2005

*What is known?

USGS, 2000

USGS, 1997

*Spatial Variability of Mercury Methylation

*“New approaches are necessary to better elucidate, track, and quantify Hg sources and transformations in the environment” (Bergquist and Blum); especially methylmercury.

*Mercury exhibits both mass dependent and mass independent fractionation in ecological pathways though photoreduction is the only mechanism that exhibited significant mass independent fractionation (MIF in MeHg is more pronounced than iHg during photoreduction experiments).

*Degree of MIF is greater in large dissolved organic carbon (DOC) conditions

*Fractionation may be dependent on the type of DOC (GSL and wetland sediments)

*Isotopic Signatures

*Affect to organisms

*Brine shrimp have been found to have elevated levels of Hg in summer/fall (Naftz, 2008)*Eared grebes Hg concentration increased

three-fold over the fall molting period (Naftz, 2008)*Many duck species have exceeded EPA

limits (.3 mg/kg Hg dry weight) (Peterson, 2008)*What about other organisms/plants?

*Extension: Mercury in Ecuador

Figure from Greg CarlingImage from Greg Carling