Saturday, June 20th, 2009
Algae toxin levels drop considerably
Ohio EPA has not canceled advisory on ingesting water
By Nancy Allen
Algae toxin levels in Grand Lake have lowered considerably during the last few days, but not enough to cancel an Ohio EPA advisory recommending people limit their contact with the water.
Samples taken from the lake on Tuesday ranged from 13.9 parts per billion to 23.3 parts per billion. The World Health Organization sets the recreational water exposure limit for the toxin at 20 parts per billion.
Water samples taken from the lake just four days earlier on June 11 produced toxin levels ranging from 28.9 to 72.2 parts per billion.
"Right now it looks good," said Ohio EPA spokeswoman Dina Pierce. "Levels of microcystin have dropped a lot and only one spot remains over 20 parts per billion."
Pierce said they are recommending the contact advisory remain in place because the site sampled at the east beach, located east of the Grand Lake St. Marys State Park office, is still above the 20 parts per billion.
Celina's treated drinking water continues to test negative for the toxin, data shows. Grand Lake is Celina's sole source of drinking water.
Pierce said the EPA is trying to learn more about the microcystin toxin, saying this is the first time the EPA has dealt with it in Ohio. It is not totally understood why blue-green algae produces the toxin at certain times and not others, she said.
Most of the sediment and nutrients in the shallow, manmade lake come from runoff from farm land, the major land use in the ag intensive watershed, Ohio EPA water tests have shown. Excess nutrients feed the blue-green algae, which produces the toxin.
Right before Memorial Day weekend, the Ohio EPA, Department of Natural Resources and Department of Health issued a warning that levels of the toxin in the lake were high enough to warrant warnings about swimming, jet skiing and water skiing - activities that might result in ingesting water. Boating, fishing and sunbathing, activities unlikely to cause people to swallow the water, should still be safe, Pierce said.
The toxin can cause skin rashes, and if ingested, nausea, diarrhea and vomiting. It also can cause weakness or dizziness, breathing difficulty and convulsions, information from the Ohio EPA states. It is particularly deadly to small animals such as dogs, Pierce said.
On Wednesday the Ohio EPA announced a Web page has been created so users of Grand Lake can check algae toxin levels before making a decision to use the lake.
The site is www.epa.state.oh.us/pic/glsm_algae.html. There are several links to the sampling data, fact sheets, news releases and other information.