Student hopes to refine testing method
for arsenic in drinking water © Aug. 7, 2009, Norwich University Office of Communications
Leading health organizations are alerting the public that levels of arsenic in drinking water may be too high, even in developed countries.
In the United States, the official safety threshold for arsenic is 10,000 parts per trillion, but the World Health Organization recommends 170 parts per trillion, and the Harvard School of Public Health now recommends just 10 parts per trillion.
One part per trillion is equivalent to about one drop of water in 20 Olympic-size swimming pools. There is no easy or inexpensive test for such minute concentrations.
It’s a real problem, and Norwich University junior Jeff DeFelice is trying to find a practical solution. He spent the summer of 2009 developing a testing apparatus and process that could drastically improve the ability of health officials to measure arsenic levels in water. He’s building a mechanism that would be the first routine laboratory test for detecting levels of 10 parts per trillion. Although the design isn’t complete, DeFelice has made considerable progress and hopes to continue his work next summer.
No one has ever done this before. So you see if things work, and if they [don’t] you try to figure out why they
~ Jeff DeFelice,
on laboratory research
“This was definitely a different experience,” said DeFelice, a chemistry major who chose a nonmilitary lifestyle at Norwich, the country’s oldest private military college. “It was working alone as opposed to being in a class lab. ... You did this work for yourself.”
DeFelice’s research was completed with the help of the Norwich Summer Research Fellowship Program, through which he earned a stipend. He worked under the mentorship of Professor Seth Frisbie, who has extensive experience in arsenic testing.
The chemistry professor, with the help of several Norwich students and his wife, sociologist Erika J. Mitchell, worked with an international team of scientists to develop a laboratory method that detects arsenic at 10,000 parts per trillion.
Frisbie often travels to Bangladesh, where high concentrations of arsenic in drinking water have led to melanosis, keratosis, blackfoot disease and sores that are open to secondary infection. In developing countries such as Bangladesh, arsenic levels in drinking water often can only be tested at 50,000 parts per trillion, five times the U.S. safety recommendation.
DeFelice met Frisbie as a student in a general chemistry class during his freshman year. “I went to him and asked him about changing my major,” said DeFelice, a civil engineering major at the time.
The pair found common ground. “I was interested in water sanitation,” he said.
This research is helping DeFelice, who is from Warwick, R.I., prepare for graduate school, and the experience has been a change from regular classroom learning.
DeFelice is using a process called gas chromatography-mass spectrometry to measure arsenic levels. He is building on the process that Frisbie and colleagues used, called the arsenomolybdate method. In it, arsenic is removed from a water sample and converted into arsine gas by a chemical process. The arsine gas is converted to arsenic acid, which reacts with four more chemicals to form arsenomolybdate. That substance is measured spectrophotometrically, which determines a substance’s structure by its ability to absorb light.
DeFelice built on this process by using a gas chromatograph-mass spectrometer, which is an instrument used to determine the compound makeup of a gas sample.
“We used this instrument to identify arsine gas in drinking water samples by building an apparatus that traps and concentrates the arsine gas in a U-trap, immersed in liquid nitrogen, before passing the sample through the gas chromatograph-mass spectrometer,” DeFelice said. “We generated the arsine gas by using the techniques in Dr. Frisbie’s arsenomolybdate method.”
DeFelice spent most of the 10-week period designing and building the apparatus, and then finally testing it to see if the gas chromatograph-mass spectrometer detected arsine.
“This was more trial and error,” DeFelice said. “No one has ever done this before. So you see if things work, and if they [don’t] you try to figure out why they didn’t work, as opposed to if it didn’t work and you get a bad grade.”
DeFelice presented his research, successes and challenges [such as a need for better temperature control] to peers and professors in July. There, he got enthusiastic feedback and suggestions to improve the apparatus.
Once working, this testing method could be refined by other Norwich students.
”We’re hoping to hand off to the engineering department,” said Frisbie. “Hopefully next year, Jeff will get another research grant,” and continue his work. The engineering department has expressed interest in automating the apparatus, and there is potential to work with the business students to analyze the market, he added.
DeFelice is the third student Frisbie has mentored in the research fellowship program.
“For me, it’s part of the deal—to help students out,” said Frisbie. “The goal is for them to learn research, so they can see what graduate school is like.”