A state agency is poised to bar big ships from dumping untreated ballast water that can contain invasive species into Duluth-Superior harbor.
Weary of waiting for federal action, the Minnesota Pollution Control Agency is scheduled to vote on a precedent-setting rule today that will prohibit ships from dumping untreated ballast water into Duluth-Superior harbor and other state waters.
State officials say they have to act because Duluth receives far more ballast water than any other Great Lakes port, making it more at risk from invasive species.
"They come in and compete with native organisms for food, and you get an imbalance that upsets the ecosystem," said Mary Jean Fenske, manager of the MPCA vessel discharge program. Invasive species also have cost millions of dollars by clogging water intake pipes for industry and reducing recreational fishing, she said. The state's proposal would require all large ships to begin treating their ballast water before dumping it, beginning in 2016. Possible treatment includes filtering through extremely fine screens or sand; using chemicals such as chlorine or ozone; or applying methods such as ultraviolet radiation or heat.
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