Can sewage treatment plants protect fish from the chemicals in the water?
So you know the saying, right? Stuff flows downhill? Myron Erickson knows a lot about that "stuff."
He heads up the sewage treatment plant that sits along the Grand River in Wyoming, Michigan (right next to Grand Rapids).
The screening room is where they take out the "grit." Erickson calls them "knick knacks."
"It's a small particle like sand, and also all things that come to us in sewage, like peas, and corn, and peanuts," says Erickson.
These screenings get dumped in a landfill, but that's just a start of what this treatment plant is designed to remove.
Settling ponds, specialized bacteria, and chemicals can take out all the stuff that might harm us – the viruses and bad bacteria that can make us sick.
But there are a lot of other things that come into this treatment plant.
“We see Tylenol, you know, acetaminophen. We see ibuprofen. We see DEET, and human hormones, because a lot of people are on hormone therapies - mood-altering drugs, anticonvulsants, antibiotics - everything under the sun, you can find it in sewage,” Erickson says.
A treatment plant helping researchers
He knows this because he began testing for it at this sewage treatment plant six years ago.
Most full-scale sewage treatment plants don't or simply won't test for this stuff.
Most full-scale sewage treatment plants don’t or simply won’t test for this stuff.
But Erickson has been able to gather a lot of data – which is great for researchers such as Nancy Love at the University of Michigan.
Love studies how sewage treatment plants are dealing with tiny amounts of so-called “emerging contaminants.”
"So very, very, very low concentrations, but it’s the active pharmaceutical ingredient that’s important," says Love. "And down at the nanogram per liter level, there can still be active pharmaceutical reactions down at the organism level. Certainly by fish, we’ve seen that now."
Scientists have established that fish can be feminized
Scientists know that fish are changed by certain hormones and other endocrine-disrupting chemicals.
The endocrine system controls how an animal grows and how it behaves.
Researchers have found that a synthetic compound in birth control pills and other hormone drugs can feminize male fish.
- They’ve witnessed this reaction in labs (here's a story we did back in 1998).
- And they’ve caught feminized male fish in the wild (the USGS found a lot of feminized smallmouth and largemouth bass throughout the U.S.).
Love says the good news is that sewage treatment plants might be able to tweak technologies already in use to address the problem.
"Can we do a little more to get significantly more removal, or conversion into a compound that is not a human risk or an ecological risk?" - Nancy Love, University of Michigan
“So the question is, ‘Can we do a little more to get significantly more removal, or conversion into a compound that is not a human risk or an ecological risk?',” says Love.
Zeroing in on the right compounds
But first they need to identify the right chemicals to target.
So before we spend money on controlling this stuff, Love says we need more research.
Research that will help pinpoint which compounds are causing problems – and how big those problems are.
Cheryl Murphy and her team at Michigan State University are testing a compound found in birth control pills and hormone drugs. It’s a compound that has not been studied before.
"Are the fish able to uptake it into the gills and make it biologically active? We don’t know," says Murphy. "And so if it becomes biologically active, that means it will induce yolk protein in the male fish."
So, like other tests have found, this compound might cause boy fish to make eggs. That’s not normal.
Biologists want to know more about what this might be doing to fish in the wild.
"The fish are like the sentinels because they're immersed in it constantly, so they have nowhere to go. They just get everything." - Cheryl Murphy, Michigan State University
What's happening to fish populations?
Murphy says with the thousands and thousands of untested chemicals out there – coupled with all the different types of fish species – it can be hard to figure out what’s really going on.
She and other toxicologists are working to find out what these compounds, at the levels found in the environment, can do to fish on the molecular level. When they have that information, they can run computer simulations to attempt to figure out what might be happening to fish at the population level.
"The fish are like the sentinels because they're immersed in it constantly, so they have nowhere to go," says Murphy. "They just get everything."
More work needs to be done to explore exactly which chemicals – or what mixture of chemicals - are changing fish – and to figure out how widespread this problem this is.
When we have a better handle on that information, wastewater treatment plant operators like Myron Erickson might be able to change some of their practices to take this stuff out of the water.
- Michigan Radio's Rebecca Williams contributed to this report.