Seeking Real-Time, Early-Warning Device for Harmful Algal Blooms

By Moira Harrington

Matt Smith and Todd Miller spent a lot of time last summer at the lagoon in Milwaukee’s Veteran Park, but it wasn’t a break from work.

The summer lagoon was a sampling spot for these two researchers based at the University of Wisconsin-Milwaukee. They are constructing and testing an autonomous device that measures toxins from blue-green algae blooms, otherwise known as harmful algal blooms (HABs).

HABs spring from cyanobacteria that are naturally present in Wisconsin waters but get active — and can be harmful to human and animal health — when conditions are right during warm months.

Conditions were right multiple times in 2017. In two high-profile instances uncovered by Smith and Miller’s monitoring, major events were affected. In June, an international “extreme” water skiing competition sidelined athletes from 31 countries because the HABs produced a toxic compound known as microcystin, which is the toxin the team’s device will measure. The Milwaukee Dragon Boat Festival in August was moved to Lakeshore State Park because the lagoon’s water quality was dangerous to human health.

Public health officials exercised caution in these instances because microcystin poses a danger to the liver, brain and reproductive organs of humans, particularly children. The blooms can also kill pets and wildlife, including fish living in the affected water. HABs are perhaps best known in the Great Lakes region as the reason behind the 2014 drinking water crisis in Toledo, Ohio, fueled by nutrient loading into Lake Erie. For three days, nearly half a million people had unsafe water flowing from their taps.

Current methods to keep Toledo residents — or water skiers, dragon boat captains or really anyone using the public water supply — safe, require technicians to collect water samples, return to a lab with the samples, do a chemical extraction from the sample and set about finding the toxins. Next comes toxin analysis through one of various methods, checking what kinds and how many of those kinds are present in the sample. The entire process is time-consuming, labor-intensive and costly.

Here’s where Professor Smith of the School of Freshwater Sciences, and Miller, professor in the Zilber School of Public Health, come in. They are co-investigators on a Sea Grant-funded project, “An In Situ Molecular Detection System for Microcystin Monitoring.”

“Our system pulls in a water sample. We filter it and get rid of the water because that’s not really what we’re interested in. Then, we extract the particular toxin that we are focusing on from the cells that we captured on the filter. By looking at the toxins contained inside the cells, we hope to create an early-warning system that can detect toxins before they are released into the water, thereby causing problems for drinking water,” Smith said. “We determine if we need to purify that sample further or whether some of the detection strategies we’re looking at can directly detect them.”

The UW-Milwaukee team has formulated solid sampling and extraction protocols, so they’ve taken the next step in connecting with Chemistry Professor Maria DeRosa at Carleton University in Ottawa.

DeRosa has helped them overtop the detection-within-a-sample speed bump. She uses a method employing DNA aptamers. Aptamers can bind tightly and recognize other molecules, such as microcystin. Then, the microcystin concentrations can be quantified.

This collaboration draws a workable detection and early-warning system ever closer. It would join a few commercial systems on the market. At this point, Smith termed those current offerings as expensive and requiring high maintenance.

Miller and Smith are aiming for a different niche. “What we are trying to do is, No. 1, make a device that is open source and affordable,” Miller said. “No. 2, we want some universality to it. What I mean by that is that it’s not just a device that can detect this one toxin but that you could easily adapt to a new chemical, whether that be a marine toxin or whether that be, for example, an oil chemical or a fuel chemical you want to monitor in the Gulf of Mexico.”

Smith hopes for a prototype device by end of the year.

The big picture, Miller reflected, is, “It is real nice when you do something that has immediate results, consequences and application to the taxpayer or the community.”