The amount of toxic mercury in Minnesota walleye and northern pike has been going up since the mid 1990s, the Minnesota Pollution Control Agency reported Tuesday. The unexpected increase in mercury was found in an analysis of 25 years of fish from 825 Minnesota lakes by the PCA and published last week in the journal Environmental Science & Technology. The increase surprised scientists because mercury levels in fish had been slowly but steadily declining in recent decades. "It's surprising.
Cutting small trees and brush for energy can be done without harming Minnesota's northern forests, but the cost to do the work may be more than the profit. That's the finding of the first comprehensive study of the environmental effects and economics of cutting so-called woody biomass. Researchers looked at nine plots on the Superior National Forest before and after loggers cut the wood -- brush and small trees ignored by paper or boards.