Dr. Richard Brase collecting macroinvertbrates with a net from their aquatic environment. Provided by Dr. Richard Brase

Clinging to a submerged log in a nearby stream and under some woody debris is a little critter known as a macroinvertebrate. These aquatic beings include tiny organisms and the larval stages of insects like worms, crustaceans, snails and dragonfly larvae. Visible to the naked eye, these creatures are not just known for being small and backboneless but are also good indicators of water quality. Recently published in Chemosphere, Environmental Health Sciences Ph.D. and Marist Alumnus Dr. Richard Brase used these seemingly trivial animals to monitor contamination in two streams in the Hudson River Watershed.

“We want to know if we could use these aquatic bugs to understand PFAS [per-and polyfluoroalkyl substances] contamination in the environment, better than we could using surface water alone,” Brase said.

Per-and polyfluoroalkyl substances (PFAS) are “forever chemicals” used to make non-stick cookware products, oil-and grease-resistant food packaging and stain-resistant carpeting. Since these man-made compounds have a strong molecular bond structure, they are difficult to break down. Even with current regulations to reduce their use, they continue to contaminate areas of the environment.

The Hoosic River flows directly through the town of Hoosick Falls, where in 2016 PFAS were detected in the local water supply and in private wells in the area. Brase and his team tested this river, and PoestenKill River as their control to measure how effective their macroinvertebrate protocol was.

“There were some pretty high levels of PFAS measured in the drinking water. So, we knew that we would be able to detect different PFAS from BMI [benthic macroinvertebrates] in the Hoosic River. If we couldn't detect them there then the method probably wasn't that sound, and the Peekskill River was originally meant to be our control,” Brase said.

Originally, the PoestenKill River was measured as the control site but as a secondary outcome, it ended up comparing a more highly contaminated site to a less contaminated one. The benthic “bottom-dwelling” macroinvertebrates in the control river site indicated a presence of PFAS but to a lesser degree.

“We picked these rivers because there was most likely some form of PFAS contamination; something to actually measure and get quantitative data from,” he said.

While a good source of food for fish, bottom-dwelling macroinvertebrates are commonly known for being used as tools for understanding water quality; however, very few studies have used freshwater benthic macroinvertebrates to monitor PFAS.”

Even though these “forever chemicals” have been around since the 1940s, there is no direct answer as to why there have not been many studies using freshwater BMI’s. Brase suggests it may have to deal with the modern relevance and the history of BMIs being used for persistent organic pollutants and some heavy metals instead.

Highly soluble in water, these popular and harmful substances don’t have as much street credit as substances like lead, which the newly published author says has been on everyone’s radar for a much longer time.

"You'll see a lot of studies done in the aquatic environment; I think probably one of the first things people will go to then is using fish for bio-monitoring,” he said. “And some unique research has been done on examining PFAS levels in higher trophic level organisms.”

A former professor of Brase’s used polar bear samples to demonstrate the ubiquity of PFAS contamination in the environment, but that isn’t always practical because of time, cost and accessibility to certain such resources.

Four of the eight macroinvertebrates taxa collected from the Hoosic River. Provided by Dr. Richard Brase

Before collecting data through these small, yet vital organisms between August and October of 2020, Brase was inspired by his former Marist advisor Dr. Zofia Gagnon, associate professor of environmental science.

Brase was fortunate to be exposed to analytical chemistry and learn new techniques through Gagnon’s guidance. “Dr. Gagnon taught a small group of us as her research students, and we all learned the techniques together,” he said. That is when Brase got to use research instruments such as inductively coupled plasma optical emission spectroscopy (ICP-OES) and mass spectrometry.

Graduated from Marist in 2016, Brase has since branched out from his undergraduate work and used what he learned then and has applied it to his work today.

Brase and his team collected these bottom-dwelling critters and broke them down by eight taxa: mayflies, hellgrammites, water pennies, caddisflies, stoneflies, crayfish, dragonflies and true flies. All these taxa except for the crayfish were aquatic insect larvae used in the study. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were the most common PFAS that were found in these critters.

Mayflies and hellgrammites were tied for highest PFOS at the Hoosic downstream site and where Hellgrammites were the highest PFOS at the Hoosic upstream site. They are highly sensitive to pollution and generally leave a water body if it is poor quality. Other BMIs, like the mayflies and Hellgrammites, do the same thing.

Brase’s study differs from what other state agencies typically do when using BMIs for water quality assessment by directly quantifying levels of contaminants in the organisms. He suggests performing similar studies on a routine basis would allow researchers to collect larger amounts of data to better understand PFAS contamination in the environment.

Generally, many researchers put the collected organisms together in a plastic bag filled with ethanol to preserve them and would then count how many individual species there are. Brase says that a diverse group of macroinvertebrates will indicate good water quality. This method would not work well for PFAS testing if one is interested in breaking the BMI taxa down and comparing the levels in different species, which Brase and his team performed.

“We kind of figured out in an early experiment, that if you put BMIs in a solution of alcohol, the PFAS begin to extract from their whole bodies, even before blending them up and turning them into bug juice for your PFAS extraction,” he said. “Because of this, one adaptation that would probably be necessary would be to essentially separate all the different taxa in the field prior to adding them to a solution of ethanol or methanol for preservation.”

Interestingly enough, Brase speculates that by breaking down the BMI taxa and the amounts of PFAS found in each, it could be possible to see where the contamination is coming from.

“You could start doing some interesting things with that data [such as] source tracking,” he said. “If we're seeing these specific PFAS in these kinds of bugs, is there a way to determine where the contamination is coming from?”

Now, working for the New York State Department of Health after finishing his Ph.D. this December at the University at Albany School of Public Health, Brase is working on a grant that characterizes PFAS in landfills across the state and doing some work on drinking water analysis for PFAS.

After working a lot with these tiny, but visible critters for a year, Brase hopes his study will broaden public awareness about the kind of contaminants that can lurk in the aquatic environment and for state agencies to see if their current BMI protocols could be improved.

“I'm hoping that people see the value in the data that we're showing here, and how we can gather more data to better understand PFAS contamination in the aquatic environment,” he said. “It’s imperative to understand what kind of things we as a population are exposed to and what that might mean for an individual's health and for public health as a whole.”

“This paper is just another piece in that puzzle to help people gain awareness of what's in the environment and why we should care about it,” he said.

Understanding Water Quality with Little Critters

MARIST CIRCLE