Although they have long been known to clog boat motors and cut people’s feet, zebra mussels pose a much more dangerous threat to area lakes then people might previously have realized.
Orlando ‘Ace? Sarnelle, an associate professor in the Department of Fisheries and Wildlife at Michigan State University, studied Oakland County lakes in 2002, including Lake Orion, where he said he and his colleagues found highest levels in the county of a toxin caused by algae created by zebra mussels.
‘We got interested in it because people had already seen things happening in the Great Lakes (with zebra mussels),? Sarnelle added. ‘But at that time, they couldn’t tell if zebra mussels were the cause.?
According to Sarnelle, lakes that have zebra mussels have, on average, three times higher levels of a blue-green algae called ‘microcystis,? which produces a toxin.
‘The zebra mussels just promote the algae that causes the toxin,? he added. ‘It’s a liver toxin…if you were to ingest it in high enough quantities, it could cause severe liver damage, and in some cases if the quantities were high enough, even death.?
When Lake Orion was initially sampled, samples were only taken from the middle of the lake. Sarnelle would be curious to know what the toxin levels were near the lake’s shore, where pets and children are more likely to be in the water.
‘Unfortunately, we don’t have the money to do that this summer,? he said. ‘The Lake Orion Lake Association (LOLA) had contacted me about paying for samples to be examined at the lab at MSU, so I put them in touch with my colleague who runs the lab.?
Ed Roberts of the LOLA said the association had offered to take samples, deliver them to MSU and pay the lab costs. The LOLA is already performing water quality tests on the lake as part of the Cooperative Lakes Monitoring Program (CLMP).
‘He put me in contact with someone, but I haven’t heard back from anyone yet,? Roberts said. ‘They both talked like they’d be contacting me before the end of June, or coming down here…but I haven’t heard anything.?
Roberts planned to call MSU again to see if they could look at anymore samples from Lake Orion.
Zebra mussels, which average in size about the width of a penny, are found in many Oakland County lakes. According to Sarnelle, in the initial sample of Lake Orion, MSU found the highest concentration of the zebra mussel algae-created toxin, at 69.9 nanograms (one-billionth of a gram) per one liter of water. There are 1,000 nanograms in a microgram.
The toxin level would have to be over 1,000 nanograms per liter before it would begin to affect a human being. Sarnelle has not yet heard a report of anyone becoming ill from the toxin in the State of Michigan.
‘The levels in Lake Orion are not very high in comparison with how much it would take to make you sick, but they are the highest we’ve measured,? Sarnelle said. ‘But we took a sample through the upper mixed layer of the lake (about 1-20 feet).?
According to Sarnelle, the algae causing the toxin will appear green on the surface of the water.
‘If you don’t see that, it’s probably not a problem,? he said. ‘If you do, you don’t want your dog drinking from that water.?