A view from the Islands: phosphorus in the lake

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(Host) Despite its beauty, Lake Champlain is in trouble. Much of the lake fails state water quality standards, and pollution can cause unsightly and dangerous algae blooms. How healthy is Lake Champlain?

VPR’s John Dillon looks into that question in part four of our series “A View from the Islands.”

(Dillon) University of Vermont grad student Emily Brines stands in a small boat and dips a small mesh net into the murky waters of Missisquoi Bay.

(Brines) “This is a 63-micro net and we just do a tow so that we can concentrate the plankton and get a better idea of what’s out there.”

(Dillon) It doesn’t look good. The water is thick, soupy and green. That means it’s full of blue-green algae, a microscopic plant that produces a nerve toxin in high concentrations.

(Brines) “There’s definitely a lot in the water, definitely a lot. So those are probably all blue-greens you see in there. So even though it’s not forming scums on the surface, it’s pretty dense.”

(Dillon) The algae is a sign that this part of the lake is sick. The shallow bay gets inundated with phosphorus and other nutrients from farm waste and city streets. The phosphorus acts like fertilizer. And in the hot days of summer, the algae blooms into millions of potentially deadly colonies.

Last year, two dogs died after drinking water from Missisquoi Bay. The Quebec health ministry has told swimmers to stay out of the bay because of the toxic organisms. The Vermont Health Department hasn’t yet posted warnings on this side of the border. But researchers keep a close eye on the toxic algae levels and they say it’s probably only a matter of time before some Vermont beaches will have to be closed as well.

At her laboratory on the shores of Lake Champlain in Burlington, University of Vermont scientist Mary Watzin leads the research project. She says the algae blooms have gotten much worse over the last several years, and researchers don’t know why.

(Watzin) “With blue-greens we haven’t figured it out. We know that reducing phosphorus, bringing those nutrients down, is going to help. But we don’t know all the other things – why is it that right now, this toxic problem is so intense? There’s something else going on besides the nutrients, and we need to figure that out too.”

(Dillon) The scientists do understand one problem that’s especially troubling for the lake clean-up efforts. Even though, New York, Vermont and Quebec have tried to control the nutrients that get into the water, there will be a long lag time before any improvement is seen.

That’s because the phosphorus that’s already trapped in lake and river sediment will pollute for decades. Watzin says the lake chemistry causes this time release effect. The phosphorus in the sediment is released as the phosphorus levels in the water are reduced.

(Watzin) “And so you’re essentially pulling phosphorus out of the sediment until you get to another balance. And unfortunately for areas like Saint Albans Bay, we’re talking about decades, and not years. We’re talking about probably 20 years or so until that process is complete. And that’s a very troubling thing. It’s very hard for people to accept that what they’re doing now, they may not see it, it may be their children that are going to benefit.”

(Dillon) Environmental groups have called for accelerated clean up efforts. And some state officials aren’t encouraged by the progress to date. Eric Smeltzer studies Lake Champlain for the Vermont Department of Environmental Conservation.

(Smeltzer) “And what we found is not really a very good picture. Several of the areas of the lake are not meeting their in-lake phosphorus water quality standards. And those areas are the main lake region, which is the big open water area off Burlington, part of the south Lake, Missisquoi Bay, Saint Albans Bay and the northeast arm, or the Inland Sea.”

(Dillon) Smeltzer says that in some areas of the lake – such as Saint Albans Bay and Mallet’s Bay north of Burlington – phosphorus levels are getting worse, not better.

(Smeltzer) “We’re not sure of the reasons for that. But apparently we haven’t done enough to reduce phosphorus inputs, particularly from non-point sources over the years.”

(Dillon) Smeltzer says the state has done a good job to control pollution from sewage treatment plants. Researchers say that so far, the pollution controls have cut phosphorus pollution by 38 metric tons a year.

But environmentalist Rob Moore says these efforts are inadequate. Moore, who holds “The Lakekeeper” position at the Conservation Law Foundation, says many treatment plants aren’t operating at full capacity. When the population grows, he says the facilities will pump even more phosphorus into Lake Champlain.

(Moore) “So until we really start taking a serious look at how can we get real reductions in pollution, I don’t think we’ll ever attain a healthy Lake Champlain. And I don’t think we’ll even be able to stop the slow degradation that Lake Champlain continues to experience.”

(Dillon) Phosphorus reduction is a top goal of a lake management plan signed by New York, Quebec and Vermont. The plan calls for the reduction targets to be met by 2016. Environmentalists want the clean-up goal moved up to 2009, to coincide with the 400th anniversary of Samuel de Champlain’s voyage of discovery down the big lake.

For Vermont Public Radio, I’m John Dillon.

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