Quantifying that pond smell

On a Tuesday in late June, Coty Jen and three students took their new kayak out on Green Lick Lake, southeast of Pittsburgh. There, the Pennsylvania Department of Environmental Protection (DEP) trained them to collect water samples from harmful algal blooms, as part of a new partnership.

When DEP gets reports of harmful algal blooms (HABs), they need to determine if it is safe for people to be in the water, for swimming or other recreation. Jen, an assistant professor of chemical engineering, and her research group are interested in determining if emissions from the algae could also be unsafe. “We know it’s harmful to swim in and ingest these blooms. We don’t yet know the inhalation effects,” says Christine Troller, a Ph.D. student in the Jen Lab who is leading this project.

Some emissions from algae are known to participate in reactions in the atmosphere that produce carcinogens. Jen and Troller are researching the potential aerosolization of toxins and compounds that may potentially become toxic.

In other words, they’re quantifying the bad smell you might have noticed near a pond.

The peak season for harmful algal blooms in Pennsylvania is usually mid- to late-August through September. As the climate warms, HABs are occurring earlier, more often, and in new places, like rivers. Runoff from farms and yards and sewage overflows are also factors. HABs are no longer only a rural problem. The risk of human interaction with harmful algal blooms is increasing.

We know it’s harmful to swim in and ingest these blooms. We don’t yet know the inhalation effects.

Christine Troller, Ph.D. student, Chemical Engineering

In Pennsylvania, harmful algal blooms are most commonly caused by cyanobacteria. Troller will be sampling water from Green Lick Lake throughout the season. The DEP is analyzing biological toxins, and the Jen Lab is conducting air analysis, to see if there is a change in the concentration of cyanobacteria and the gaseous toxins they produce.

Troller starts measuring emissions the same day she collects the two-gallon samples, to get as close as possible to measuring the emissions from the algae in their natural habitat. “There is some uncertainty because anything biological gets upset when you take it out of its environment,” says Jen.

In their lab in Doherty Hall, Troller puts each sample on a tank connected to a mass spectrometer. The gas phase emissions coming from the tank flow directly into the mass spectrometer. Over the course of a week, Troller continues measuring the gaseous concentration of hundreds of different compounds that are emitted from the water sample. She is identifying the compounds, many of which are unknown, based solely on their molar mass.

She will share information about potentially hazardous compounds with a PA human toxicologist. The findings will help determine if they can set standards based on gas measurements for when it is unsafe to be on the shoreline near a harmful algal bloom.

The Jen Lab is also developing two new instruments that could collect air samples from the environments where harmful algal blooms are reported. The goal is to create smaller, battery-powered, and less expensive instruments. Instead of being limited to collecting air samples from shore or taking water samples back to the lab, researchers could take these new instruments out on the water in a kayak, to measure the air directly above harmful algal blooms.

The Jen Lab’s larger interest in understanding the atmospheric effects of emissions from algae relates to cloud formation. The connections between particles and clouds are a major uncertainty in climate science. Compounds emitted by algae help form seed particles for cloud droplet formation. “There’s very little experimental data that modelers use to predict cloud formation,” says Troller. “Our research will add to the accuracy of those predictions.”

Pictured, top: Christine Troller (in the yellow kayak) on Green Lick Lake with scientists from the Pennsylvania Department of Environmental Protection.