Students take deep dive into Lodi water health
Lodi Storm Drain Detectives get lesson in water science
On Thursday afternoon, Storm Drain Detective students gathered around a table in a high school science lab, carefully peering into small vials of water containing water fleas.
The results showed that the samples collected from local water sources weren’t toxic for the water fleas.
“There is no statistical difference,” Dr. Stephen Clark noted while looking at the results. “All four samples were relatively similar. None of the samples were toxic within 48 hours to the water fleas.”
The fleas were living in water samples that were collected at four different locations around Lodi: upstream of Lodi’s storm water system in the Mokelumne River; from runoff downstream of Lodi’s storm water system in the Mokelumne River near the Woodbridge Irrigation District office; at the Lodi Lake storm water pump station; and at White Slough — with waste water effluent — 100 percent clean wastewater that had been treated by the water treatment plant.
There were also two reference toxicant samples, which showed two different levels of salt — a stressor for the water fleas, and a control.
The first day of the threeday workshop gave students an overview of environmental toxicology and method description. The second day students initiated the test, and the third day — 48 hours after the initiation of the test — they gathered data.
The free workshop for high school students was organized by Kathy Grant, director of the City of Lodi Watershed Education Program. It was led by Clark, vice president of Pacific EcoRisk.
The workshop reinforced basic science principles, Clark said. The students designed an experiment, used a new method, and interpreted the data collected.
“It’s a true science experiment,” Grant said. “Students dropped water fleas into water and came back 48 hours later to count and figure out if any water was toxic to them.”
The rigorous protocol is similar to the test the wastewater industry uses to determine whether treated wastewater, or effluent, is safe enough to discharge to local waterways, Grant said.
An important lesson for the students was to base their results only on what the data told them.
Alongside the students, Clark ran a professional experiment which validated the students’ findings. He
“What’s good (is that) the workshop looks like if you work in a lab. (Dr. Stephen Clark is) treating them like interns, teaching them about safety and the importance of creating negative controls.” KATHY GRANT DIRECTOR, CITY OF LODI WATERSHED EDUCATION PROGRAM
took the same samples of water and ran a 24-hour trial.
“What’s good (is that) the workshop looks like if you work in a lab,” Grant said. “He’s treating them like interns, teaching them about safety and the importance of creating negative controls.”
The team of students set up a control using salt water at two different stations. That water killed the fleas, showing the students an example of toxicity.
They also used several bottles for the testing to ensure they had a wide range of results to work with, Grant said.
Student Lauren Schwabauer said she learned a lot about what’s in Lodi’s water.
“And how well organisms can survive in different water,” Halley Lauchland added.
The workshop was really interesting to see the effects water can have on living things and bacteria, junior Dylan O’Ryan said.
“It’s important to take care of the watershed and not pollute,” he said.
At the end of the workshop, Clark commended the students for their work.
“You nailed it!” he told the class. “You got a useful set of data.”