Updated 5:40 p.m.
Toxic blue green-algae wasn’t detected in water samples taken from the city of Lawrence’s treatment plant last week.
On Thursday, the U.S. Geological Survey released results that showed water treated at the Kaw River Water Treatment Plant, or any other water departments along the Kaw, contained no traces of the toxin.
The results come almost a week after Lawrence stopped pulling water from the Kansas River because of concerns over the toxic levels of blue-green algae that were detected upstream.
Jeanette Klamm, projects manager for the city’s utilities department, called shutting down the Kaw plant a precautionary measure and an easy decision because demand for water was low and maintenance on the plant needed to be done. The city will rely on water from its Clinton Treatment Plant in the coming weeks.
The city shut down the treatment plant late last Friday after the U.S. Geological Survey released preliminary data that showed high levels of blue-green toxins in water that was being released from Milford Lake and flowing down the Kaw.
For much of the summer, Milford Lake has been battling toxic levels of blue-green algae, also known as cyanobacteria. At high levels, the toxins can cause illness or death in people and animals. Three dogs died this summer after being in Milford Lake.
In August, levels at the lake were 80 times higher than what the World Health Organization deemed dangerous.
On Aug. 31, the U.S. Army Corps of Engineers released a large amount of water from Milford Lake, sparking concerns that high levels of cyanobacteria toxins would get swept downstream. Two days later, the USGS tested water at 14 points along the Kaw. In areas the Milford Lake water had reached, they found high levels of blue-green algae. At that point, the water hadn’t reached Lawrence.
“We have a lot of (algal) bloom events in Kansas reservoirs. We have them almost every year. The thing that is unique here is that water was being held in Milford Reservoir that needed to be released. And that (release) happened at a time (algal) toxins and taste and odor problems were very large,” said Andy Ziegler, director of USGS’s Kansas Water Science Center.
Another round of water was tested on Sept. 8, two days before Lawrence stopped pulling water from the Kaw. Results from those samples, which were released Thursday, showed that the toxins weren’t in drinking water, but could be found in the Kaw.
In areas where Milford Lake and Perry Lake flow into the river, water samples showed the toxins at a level of 4 micrograms per liter. That number was diluted farther downstream, with just 0.8 micrograms per liter in Johnson County. The World Health Organization guideline for drinking water is set at an average of 1 microgram per liter over a person’s lifetime.
The USGS will release more results next week from samples taken Monday.
“There’s a lot of science we don’t know (about blue-green algae),” Ziegler said. “With the sampling done this week and last week, we hope to learn more about what causes these events so we can know more about how to help water suppliers adjust treatments.”
Even though toxin levels weren’t detected at the Kaw plant, it won’t be operating in the next few weeks as the city continues to perform maintenance.
This isn’t the first time Lawrence had to draw heavily from the Clinton Treatment Plant. In summer 2010, a similar algae outbreak upstream left a musky taste in water from the Kaw, so more water production was shifted to the Clinton plant.
“It seems that there is a trend,” Klamm said.
While it won’t make a difference for where the city pulls its water in the short term, Klamm hopes the data from the most recent water samples will help determine what can be done upstream to fix it.
“I don’t think it’s a Lawrence issue. I think we would certainly like to see some discussion on what could be done or would be done,” Klamm said.