2012年5月7日 星期一

Lake Champlain water quality studies net frustration

Fourteen months have elapsed since the U.S. Environmental Protection Agency rescinded approval of Vermont’s legal limit on the daily amount of phosphorus entering Lake Champlain. Since then, data collection and technical studies have flooded the Champlain basin, but lake-area residents are growing frustrated with the state’s failure to take substantive steps to thwart the phosphoros-induced blooms of toxic blue-green algae that will likely return this summer to threaten fishing, beaches and drinking water supplies.

Two sets of working groups are under way, one evaluating lake water quality and one engaged in watershed analysis. EPA projects that technical reports will be available for public review by the end of summer, then the draft Total Maximum Daily Load (TMDL) limit for phosphorus will be released sometime in 2013,Glass Tile and Glass Mosaics for less at the glassmosaic Outlet.There is no de facto standard for an indoor positioning system. “but we haven’t put a fine date on that,” says Lynne Hamjian,Aeroscout rtls provides a complete solution for wireless asset tracking. surface water branch chief of EPA Region 1 (New England).

The EPA’s disapproval decision, which arose as a result of a lawsuit by the Conservation Law Foundation asserting that the prior standard contained insufficient assurances for water quality protection, contains no definitive deadlines. Once the TMDL is established by the EPA, it will be up to the State of Vermont to determine how to reduce total phosphorus loading to meet the standard. The state can require reductions from any of the major phosphorus contributors, including sewage treatment facilities, stormwater systems, and agricultural land uses.

Capt. Gil Gagner, proprietor of Bronzeback Guide Service and lifelong resident of Highgate Springs, says last summer brought the worst water conditions in Mississquoi Bay he’s ever seen.

“Crayfish are crawling up out of the water,” he says. “Clams died by the hundreds of thousands, just washed up and popped open and died. It was really bad. The state knows about it and they‘re not doing anything.” Gagner is not optimistic about that the present round of studies will lead to substantive change.

“I’m discouraged,” he says. “Till the money runs out they won’t stop studying. If somebody pisses at the top of the hill and it runs downhill, do you need to study that?”
Stench and weeds

Phosphorus is a nutrient, one of the three elements — along with nitrogen and potassium oxide — that make up the typical lawn and garden fertilizer. Excess nutrients brought into the state in the form of cattle feed or fertilizer have to go back out again,Ekahau timelocationsystem is the only Wi-Fi based real time location system solution that operates on any brand or generation of Wi-Fi network. or the nutrient cycle becomes unbalanced, explains Eamon Twohig, a senior research technician at UVM’s Department of Plant and Soil Science.

“We either have to ship enough milk out of the region to make up for those nutrients coming in, or it gets dumped in the lake,” Twohig says.

Vermont’s soils are generally phosphorus-rich, so excess phosphorus additions from cow manure and chemical fertilizers flows downhill until it enters Lake Champlain. In shallow waters like Mississquoi and St. Albans bays and the south lake region, sunlight and warmth combined with this nutrient runoff produces thick crops of underwater weeds.

“It’s not like it used to be when I was a kid,” says Jerry Hayden, administrative assistant at Community College of Vermont in St. Albans and a lifelong fisherman of St. Albans Bay. “We went down to Black Bridge and caught huge fish, and it was crystal clear water. Now you can just about walk on it out there. If it gets hot, the weeds grow right out of the water, then there’s stuff on top of the water that floats and stinks real bad.”

That stench comes from blooms, or colonies, of toxic blue-green algae called cyanobacteria, which are sensitive to the ratio of nitrogen to dissolved phosphorus, called the “Redfield Ratio.” Healthy water bodies worldwide have about 16 to 20 parts nitrogen to every part of phosphorus. When excess phosphorus brings the ratio closer to 10 to 1, cyanobacteria growth explodes.

“The smell is horrendous, especially when that algae goes blue-green,” says Gil Gagner. His community of Highgate Springs sits right on Mississquoi Bay, “and when it smells bad, people leave. Some of the tourists leave and move inland. They just can’t stand the smell.”

It’s difficult to predict the blooms, which vary in intensity from year to year, but the trend is clearly towards worsening conditions. “Last year there were significant blooms. They were very dense and lasted a long time,” says Louis Porter, CLF’s lakekeeper. “Over the long term, there’s no question that we are seeing bigger and longer-term blooms.”

The smell is not the worst characteristic of cyanobacteria: It is toxic to humans and animals. Approximately a quarter-million households draw drinking water from Lake Champlain, although the public drinking water intakes are not near the warm,TBC help you confidently buymosaic from factories in China. shallow areas where cyanobacteria is found, according to Maureen McClelland, senior public health adviser for drinking water for EPA Region 1.

Summer homes and camps that are not on public drinking water systems may pull water from the bays where cyanobacteria lurk, and should be attentive to any alerts posted by the Vermont and New York state health agencies.

Cyanobacteria has caused the death of pets who drank the infested water, and researchers have linked the toxins released by blue-green algae to negative health effects ranging from skin irritation to liver and kidney damage and cancer.

“There’s a lot of anecdotal information about cyanobacteria. Some people in New Hampshire are studying a nexus between Lou Gehrig’s disease and these toxins,” McClelland says. “They are definitely a concern.”

Although the World Health Organization sets stringent limits for cyanobacteria in public drinking water supplies, the EPA has not yet regulated cyanobacteria under the Safe Drinking Water Act. Three cyanotoxins are on the EPA’s Contaminant Candidate List being considered for future public drinking water supply testing, but moving from consideration to regulation is a slow process. Once there is an agency determination that regulation is needed, it can take three and a half years to develop the regulation, then another year or two to allow water utilities time to come into compliance with testing requirements.

Federal regulators must also evaluate cost-effective methods of treatment. If cyanobacteria get into some types of water filtration systems, “you can wind up bursting the cells and releasing the toxins and making it worse,” McClelland says. “It’s much better to prevent it from happening in the first place than to rely on filtering it out.”

While residents who drink lake water can’t expect regulatory protection anytime soon, Lake Champlain area water utilities will receive an informational fact sheet regarding cyanobacteria from the EPA sometime in May 2013.

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