Divers are planning to collect zebra and quagga mussels this week in Muskegon. It’s part of a national effort to study chemical pollution, called Mussel Watch.
The mussels are invasive species, but they’re also good study subjects.
Ed Johnson is a senior scientist with the National Oceanic and Atmospheric Administration. He says zebra and quagga mussels are ideal for studying contaminants in the Great Lakes, because they stay in one place; they don't move around like fish or birds do.
"They’re very good at accumulating chemicals dissolved in the water and chemicals absorbed onto particulates they feed upon," he says. "They tend to be less effective at metabolizing many of these chemical contaminants, so they can accumulate to levels we can more easily measure them."
Johnson says this means the mussels more accurately represent chemical contamination in the areas where they're collected, than other organisms.
He says they’re finding fewer legacy chemicals from decades ago in the mussels. But they’ve been surprised to find drugs people take in zebra and quagga mussels.
“We’re finding some of the statins, we’re finding a number of drugs used for treating depression, antibiotic drugs, we’re finding even illicit drugs, like cocaine,” he says.
Johnson says wastewater treatment plants can’t filter out many of these drugs, and other chemicals, so they end up in the lakes.
He says in addition to collecting mussels from different zones of the lakes, they also run tests on them.
“They don’t mind being in a cage for an extended period of time, so we’ve actually deployed caged mussels at the outfalls of wastewater treatment plants," he says.
Every year, scientists collect mussels from a different Great Lake. This past year, they collected samples from Lake Ontario. Over the winter, Johnson says they'll run a number of tests on the zebra and quaqqa mussels, to look for DNA damage, and other biological markers of stress.
Johnson says they’re trying to figure out if drugs and chemicals in the lake harm the mussels.
"We're not really sure yet," he says. "This is where we're treading on new ground."