Senior Lauren Barlass col­lected local water samples down­stream from the sewage treatment plant to determine phos­phate levels present in the St. Joseph River. Lauren Barlass | Courtesy

To measure very low levels of phos­phate in water samples, some­times researchers have to get cre­ative.

Senior bio­chem­istry major Lauren Barlass spent her summer researching phos­phate levels from locally obtained water samples, including the St. Joseph River and Baw Beese Lake. Most kits for testing phos­phate rely on a visual scale, which is not sen­sitive enough to detect low levels and determine whether water samples exceed local limits.

“The purpose of the research is to be able to determine even very low levels of phos­phate in natural waters,” Barlass said. “We used a spec­tropho­to­metric method to then quantify how much phos­phate was in the water through a series of reac­tions.”

Barlass said she used a flow-injection process to mix water with chemical reagents. From there, the reagents formed a blue complex with the phos­phate. This complex absorbed certain wave­lengths of light, and the phos­phate level could then be deter­mined based on how much light was absorbed. Barlass used an instrument called a spec­tropho­tometer to measure light intensity. The spec­tropho­tometer deter­mined the intensity of the blue light, so Barlass could tell how much phos­phate is in the water sample by com­paring these mea­sure­ments to a known standard.

“We were trying to use this method to see if we were able to detect even very low con­cen­tra­tions of phos­phate accu­rately,” Barlass said.

Too much phos­phate can have a neg­ative effect on plants and animals within a body of water.

“Microor­ganisms like phos­phate as a nutrition source, but there can be too much of a good thing,” said Pro­fessor of Chem­istry Mark Nussbaum, Barlass’ research adviser. “The EPA tries to ensure that phos­phate levels in natural waters are very low, so we need good ana­lytical tech­niques to test for them.”

Barlass said one danger of too much phos­phate is eutroph­i­cation, which occurs when an excess of nutrients causes an increase in plant life, such as an algal bloom, and death for animals who cannot get enough oxygen. This is one of the reasons it is helpful to have an accurate mea­surement of phos­phate levels in water.

When the spec­tropho­tometer mea­sured the level of phos­phate in water, it would show a peak that served as a con­crete mea­surement of the phos­phate level.

Barlass said she ran into a bit of trouble with some of her instru­men­tation.

“We still don’t know exactly what caused some of the problems,” Barlass said. “At some points, it would just be con­stantly having spikes up and down, even when we weren’t injecting any­thing. We had to try to trou­bleshoot it to get it working again. That took up about a week or so of my research, which is frus­trating, but by the last week, we were able to get it up and running again.”

Senior Randi Block, Barlass’ roommate, said Barlass remained pos­itive despite the dif­fi­culties she encoun­tered, par­tic­u­larly with blocked tubing that could mess up reac­tions.

“During this frus­trating process, Lauren always worked dili­gently to com­plete each day’s work and to find ways to prevent further problems,” Block said. “No matter how frus­trated she got, Lauren always took the time to help me on my own research and never lost her pos­itive attitude. I really admired her con­stant pos­i­tivity and smile.”

Nussbaum said con­t­a­m­i­nants in the water sample could interfere with the mea­surement by affecting the absorption of light at the par­ticular wave­length or by reacting with other com­pounds. Addi­tionally, he said that it is easy to get air bubbles in the tubing that can change the signal.

“In general, she got good results,” Nussbaum said. “Her numbers were sur­pris­ingly high. I’m sus­pi­cious that some­thing else might have been causing that, but I don’t know what.”

Barlass’ research also sought to expand on research another student, Ryan Wiska ’12, began in 2011.

“He only was able to test a few dif­ferent water samples, and he found that the levels of phos­phate were sig­nif­i­cantly higher directly down­stream from the waste­water treatment plant versus upstream,” Barlass said. “He hypoth­e­sized that the waste­water treatment plant was adding phos­phate somehow into the water, and so I wanted to add more samples to that to try to confirm or refute those initial results.”

Barlass said she found that the phos­phate levels were pretty con­sis­tently higher down­stream versus upstream of the treatment plant.

Nussbaum praised the work that Barlass did, espe­cially in opti­mizing the time it took to take mea­sure­ments.

“Lauren did a really good job,” he said. “She showed tenacity and ded­i­cation, sticking with it and fighting chal­lenges she faced.”

  • Jen­nifer Melfi

    great work