It's not that Minnesota's waters are more polluted every year. It's that ever year the state looks at more lakes and rivers, it finds more that have pollution problems.
The Minnesota Pollution Control Agency this year is adding 500 lakes and segments of rivers to its list of "impaired waters" for problems like too much sediment, too much toxic mercury, too much nitrogen and too much bacteria. Thirty waterways are coming off the list for specific impairments, though they may remain on the list for other problems.
The Knife River, for example, no longer is considered a problem because of the pH level of the water, which is good news. But the river still is listed for having too much mercury for fish to be safe to eat by everyone.
The state has surveyed 4,123 waterways in recent years with 2,497 found to be impaired. In all, 20,740 miles of river have been surveyed, with 14,265 miles considered impaired for at least one reason.
For the first time, the PCA looked at beaches for elevated levels of bacteria, and found several along Lake Superior in and near Duluth. Most are beaches where the state Department of Health already has been issuing occasional summer beach advisories.
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The public will get a chance to comment on the 2014 list, which goes to the federal Environmental Protection Agency for approval. The list is intended as a report card or snapshot on how the state is progressing, or not, toward upholding the federal Clean Water Act.
This year the PCA looked at 18 of the 81 watersheds across the state. In Northeastern Minnesota, the agency looked closest at the Nemadji River (and its tributaries) and at Lake Superior's North Shore and the rivers that run into the big lake from Duluth to Silver Bay.
In the Lake Superior watershed surveyed, researchers found five lakes and 32 stream segments that were impaired for one or more problems. Some had too much sediment -- called turbidity -- while others are considered impaired because of too much nutrient runoff from nearby land, such as phosphorous or nitrogen. At least eight were found to have levels of mercury considered unsafe.
"It's really all over the board for those new North Shore impairments," the PCA's Miranda Nichols told the News Tribune. "There's not a pattern or one thing we can point to that's affecting those waters."
The PCA said there's good news about 32 miles of the Mississippi River that have been impaired since 2008 because of the presence of certain perfluorochemicals in fish tissue. PFC concentrations have decreased markedly in the impaired sections of the Mississippi. Three of the four sections of the river impaired for PFCs will be removed from the impaired list.
The PCA has been ramping up the number of lakes and rivers tested each year. The goal is to finish surveying all 81 watersheds by 2018. The PCA today stressed the increase in testing and its limited success are thanks in part to cooperative efforts with local groups and projects largely funded with state Legacy sales tax funding.
"In recent years, thanks in part to the Clean Water, Land, and Legacy Amendment, MPCA has greatly accelerated its schedule for assessing surface waters. Because of that, we are finding many more water bodies that don't meet water quality standards and are impaired," Rebecca Flood, assistant PCA commissioner, said in a statement released today. "At the same time, our local partners are making impressive progress on addressing water quality problems through their actions, so in every biennial cycle, we are able to remove a few more lakes and streams from the list."
Not included in the list for 2014 are waterways that may be impaired due to high sulfate levels that may limit wild rice growth. The PCA is studying the impact of sulfate on wild rice growth and will issue an addendum to the 2014 impaired waters list when the wild rice study is complete. The sulfate-wild rice study -- determining at what level and times sulfate harms wild rice -- is considered a key issue for wastewater discharge from mines.
