By Alexandria Krause, Contributor
UNO’s aquatic toxicology laboratory, led by Alan Kolok, professor of biology, has been diligently surveying Nebraska’s aquatic resources for 13 years. The 300-mile long watershed along the Elkhorn River has become home to data collection and research on water compounds to better understand what’s in our water.
One of the main compounds Kolok collects data on is atrazine, the most common herbicide in the United States.
Biologists have been studying fish, like the fathead minnow, a locally raised baitfish, and frogs, like the northern leopard frog. Researchers are interested in discovering whether internal cell signals are affected by external variables such as compounds in water. And if so, whether the masked chemicals could produce changes in estrogen and testosterone levels or in physical traits such as breasts or testicles.
Downstream wastewater treatment plants are used to remove ammonia, biological oxygen demand (BOD) and nitrogen from water.
While this is important, “They do not remove cell signaling endocrine disruptors,” Kolok said.
There are certain effective techniques, but they’re expensive. This is where Kolok’s research comes in.
When estrogens are found in downstream wastewater treatment plants, males are sometimes feminized.
“That’s not happening in the Elkhorn River,” Kolok said.
Lindsey Knight is working on her master’s degree at UNO. Knight completed her bachelor’s degree at UNO and has been working at Kolok’s lab for three years studying the effects of aquatic organisms that are exposed to agricultural watersheds like the Elkhorn River.
In the Elkhorn River, de-feminization of female fish has been found. That doesn’t mean they’re becoming more male, they’re simply becoming less feminine. Conversely, the male fish have experienced no change.
Knight compared the results to a study of northern leopard frogs.
“[M]ale frogs that had been exposed to the river water were showing exactly the opposite response in their gene expression suggesting they were being feminized,” Knight said.
Female frogs have experienced no change.
Atrazine levels are tested using a stick that works much like a pregnancy test. Data collectors can apply a sample of the water to the strip, wait 10 minutes and see a positive or negative result.
While the test doesn’t measure the amount of atrazine present, it’s an accurate indicator. The tester measures three parts per billion-USEPA’s drinking water standard, and at about $10 a pop, they are a cost efficient way of collecting data.
The atrazine “pulse” is what researchers refer to as the spike in atrazine levels in the springtime due to surface runoff of snowmelt from agricultural fields and after rainstorms. Kolok and researchers like Knight measured for the pulse.
“I went out on the Elkhorn River approximately every three days over the spring and summer and tested the water for the presence of atrazine using test strips,” Knight said. “In addition to the atrazine pulse exposure, we did a ‘post-pulse’ follow up exposure after the pulse had ended with just the fish. There were no effects in the fish following this exposure, so basically we found that the effects only occurred during this pulse time period.”
The Elkhorn River water does not go into Omaha’s drinking water. Most of Omaha’s drinking water comes from the Missouri and Platte Rivers.
The Elkhorn River Research Station (ERRS) was officially opened in April and encourages public outreach through the data collection research project. “Citizen scientists” can now use the testing strips independently. After they complete a test, they can go to a data collecting website, find their longitude and latitude coordinates on the map, as well as the time of collection and select “yes” or “no” for atrazine found.
From Boy Scout troops to curious farmers, “It takes an army to collect data,” Kolok said. If more people are interested, more samples can be collected and at different times.
Kolok found that individuals with an interest in the land for agricultural purposes are excited to get involved. They want to know what is in their backyard.
“We don’t know if atrazine was the cause of the effects, and indeed there were a number of other pesticides detected in the river,” Knight said. “In fact, we know that the effects in the female fish were not likely due to atrazine exposure, so this basically suggests that different animals are not only being impacted by the same watershed, but that there could be completely different compounds causing these effects.”
Kolok hopes to achieve two things with his ERRS project. The first is data collection. While he doesn’t know if the atrazine compound is good or bad, “data generation is important,” Kolok said.
The second is to discover more about the combination of compounds in the water or “cocktails” as Kolok calls them. Atrazine is the number one compound found and the easiest to detect, given the availability of the atrazine testers.
“Atrazine is the canary in the coal mine” Kolok said.
Other compounds found are acetochlor, metolachlor, DEA, dimethenamid, DIA, and propazine.
“Mixtures are complicated,” Kolok said. “No two are exactly the same.”
While scientists have a good understanding of what these compounds mean alone, it is hard to understand and measure the mixtures.
“I know that in future research, one of the goals is to do continuous bio-monitoring at the Elkhorn River Research Station with fish and other aquatic animals throughout the season, so we can better characterize these compounds that are entering the watershed and the effects they are having,” Knight said.
Knight plans to get her Ph.D. after completing her master’s.
“Working with Dr. Kolok and being here at UNO has really helped me to achieve far more than I thought possible as a student. It’s weird to realize I am doing real science and doing things that no one has ever done before,” Knight said. “One thing I can say to other students, is that as an undergrad I was never aware of how many opportunities there are here at UNO to do research and to get involved.”
“It’s important to understand what’s out there,” Kolok said. “I think it’s much scarier to not understand. When we understand what’s out there we can mitigate the risks.”
