Testing our water

Microbiologist tests drinking water, lake water, and pools to keep the public safe.

From the pages of In Business magazine.

Pseudomonas, phosphorus, nitrates, and coliform are on Jennifer Lavender Braun’s daily hit list. The microbiologist for Public Health Madison & Dane County has the final say on whether rural, private well water is safe for drinking; whether chlorine at public swimming pools (in hotels and schools and parks) is within an acceptable range; or if Madison’s cherished lakes and beaches are suitable for recreation.

Braun, 34, together with chemist Glenn Hyland, and Rick Wenta, environmental protection, are the scientific superheroes waging war against microscopic threats to human health.

Their primary role is environmental monitoring, but most samples analyzed in the laboratories involve water. Heavy rainfall can make water quality worse for lakes and streams, Braun says, and while the spring of 2019 was above average for rainfall, it pales in comparison to the devastating rains of 2018, when on one particular summer day, all but one of the county’s public beaches were forced to close due to bacteria.

They scout for everything from bacteria to blue-green algae blooms, and from E. coli — caused primarily by the presence of animal and/or human fecal matter — to road-salt runoff.

And while all registered public pools at parks, hotels, and high schools are expected to test their water every day, sanitarians test pools at least twice a year for levels of chlorine or bromine. “We also look for coliform bacteria,” Braun adds. “Within that is E. coli, which tells us if there’s been fecal contamination.”

They also test public whirlpools or hot tubs looking for pseudomonas, a troublesome bacteria that can cause hot-tub rash or eye infections.


The process for monitoring private well-water samples (right) involves analysis in an ion chromatography machine.

Braun, 35, was raised in the Racine, Wisconsin area. She attended Walden III, an alternative high school in the Racine Unified School district, and was so inspired by her biology teacher that she continued to enroll in science classes beyond what was required for graduation.

After earning a master’s degree from UW–Parkside, Braun held jobs at the City of Racine Health Department and the U.S. Environmental Protection Agency in Cincinnati before accepting this position in 2010.

Now she is Dane County’s definitive expert when it comes to closing Madison’s beaches, testing the drinking water of rural, private wells, or monitoring public pools — and even some splash pads.

During peak season, between Memorial Day and Labor Day, Public Health hires two interns who collect water samples in knee-depth beach water.

Currently, 21 beaches are monitored regularly with samples brought to the fifth-floor of the City-County building for analysis. There, Braun will test for levels of E. coli bacteria, cyanobacteria (blue-green algae), and their toxins.

E. coli is an indicator of water quality and toxins, she explains, including the presence of human and animal fecal matter, which comes mostly from geese, raccoons, dogs, or rodents. If E. coli is present, there’s a chance that other things also exist that could make people sick. Recreational water illnesses, for example, can include an upset stomach or diarrhea, “and nobody wants that,” she states.

Braun’s typical day begins at 7 a.m. and ends at 3:45 p.m. In between, she alternates between the chemistry and microbiology laboratories testing drinking water samples from private, rural wells and lake water. The ion chromatography (IC) machine in this room is her friend, working around the clock to detect fluoride, chloride, nitrate, and sulfate levels, among a host of others.

This morning, Braun demonstrates a well-water test. She wishes more people would voluntarily submit samples because there are no requirements specifying how often well water should be tested.

Public Health recommends it be done annually to check for things like nitrates, which can be particularly dangerous for young families or pregnant women. “Nitrates compete for oxygen in the bloodstream and can cause blue-baby syndrome,” Braun explains.

Braun extracts a few drops of water from the homeowner’s sample and fills a tiny glass vial. She caps and labels it, and places it in a tray with other vials to be analyzed by the IC machine. It only takes about 15 minutes for results to begin displaying on a computer screen next to the machine.

“All samples being analyzed must be completed with adequate quality-control samples and data review before results can be made available,” Braun notes. This process usually takes about a day.



Across the hall in the microbiology lab, beach testing is underway from lake water collected this morning. If a high concentration of bacteria or E. coli is present, a beach will likely be closed and tested repeatedly until it can be reopened.

Thus far, this is a good day, Braun reports. The water samples have resulted in relatively few issues, and she was able to reopen the beach in front of the UW Memorial Union for swimming.

From top to bottom: 1) In the microbiology lab, Braun demonstrates a blue-green algae test. 2) With E.coli testing, a sample of lake water is poured into a Quanti-Tray, heat-sealed, and incubated before the tray is placed under UV light. 3) If the pockets, or wells, glow, E. coli is present. 4) Older beach water samples from June.

“We try to get to every beach at least once a week, usually on Mondays and Tuesdays, so samples can incubate overnight,” Braun says. Based on the test results, Braun makes the call as to whether a beach is unsafe and she must contact beach authorities and the media.

The problem is that conditions can change quickly. “We’ve seen algae blooms float away within an hour,” she reports.

Pockets of toxins

Public Health Madison & Dane County currently does not yet test for PFAS, or per- and polyfluoroalkyls, which are relatively new. Its role, related to PFAS, is to educate the public and explain the risks.

Meanwhile, in the microbiology lab, water testing continues. Braun pours a small sample of lake water into the top of a Quanti-Tray, filling dozens of moulded clear plastic pockets, or wells, with liquid. After the tray is heat sealed shut, it incubates for 18 to 24 hours. If bacteria is present, the water will change color.

To illustrate, Braun places one incubated tray filled with water that has taken on a yellowish tint under a UV light and peers through a viewfinder. Most of the wells glow, indicating the presence of E. coli.

Thankfully, the test for blue-green algae — which has proven deadly to some and certainly to water-loving dogs — checks for microcystin toxins and can be completed in less than two hours.

Water samples are boiled in a microwave before seven drops are placed into a vial containing reagents. After a period of shaking and incubating, a test strip is inserted into the tube to confirm the results.

If two black lines result — one being the control line — there is no toxin, but if only one line is visible, the water is highly toxic and should be avoided, Braun notes.

Earlier this summer during the swimming portion of the Half Ironman competition in Madison, Braun was called out on an emergency after two participants were found unresponsive in Lake Monona. Sadly, both men died.

Immediately, she collected water samples along the swimming course and quickly determined that water was not the cause of death in either case.

“I tested for bacteria and algae toxin,” she says, “and got the results I needed very quickly, but what a terrible and tragic incident.”

Braun is proud to be part of a team focused on keeping people safe. “This is a public health issue that affects the water we drink and the lakes we play on.”

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