"Mercury (Hg) release is intrinsically linked to the firing of pellets, airborne Hg emissions from Minnesota’s iron industry effectively began with taconite processing in 1949...."
Average mercury concentration in NE Minnesota precipitation is higher than dissolved mercury in most streams and lakes, underscoring the importance of sedimentation and uptake by soils and vegetation in regional mercury cycles. Atmospheric deposition of mercury from precipitation appears to be increasing or holding steady since 1990 despite large reductions in Minnesota’s statewide emission rates. Lake sediment records indicate that mercury is being delivered to lakes at rates much greater now than in pre-industrial times, but some lakes reveal recent declines.
Berndt, M. E. (2003). Mercury and Mining in Minnesota.
http://www.citeulike.org/user/HEIRS/article/8356901
files.dnr.state.mn.us/lands_minerals/mercuryandmining.pdf
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