Rosenfeldt Tackles Water Quality
By Gabriel Chen
Something fishy is happening in the headwaters of one of the nations most conspicuous riversÂ– the South Branch of the Potomac River. Scientists have discovered that some male bass are producing eggs, which is a decidedly female reproductive function. Male fishes producing eggs in the Potomac River may read like the Nebula prize-winning plot for a science fiction novel, but this phenomenon is becoming a growing cause of worry for environmentalists worldwide.
Last year, U.S. Geological Survey (USGS) scientists examined fish health in the watershed near the town of Moorefield, about three hours drive from Washington, D.C. They conducted an intensive assessment with a statistically significant number of fish. That's when they discovered a so-called intersex conditionÂ– where one sex exhibits both testicular and ovarian tissue. Some 42 percent of male smallmouth bass surveyed showed signs of intersex development. A second sampling in the spring of this year produced an even higher rate i.e., 79 percent showed sexual abnormalities.
Erik Rosenfeldt, a PhD candidate in environmental engineering, hopes his ongoing research at Duke will help provide a treatment barrier between this hormone pollution in rivers, and the drinking water we pull from such sources. His Master of Science (M.S.) in environmental engineering, which he received at Duke last year, was about the destruction of endocrine disrupting compounds in water with direct UV and UV/H 2O 2 advanced oxidation. Rosenfeldts Ph.D. research will further his MS: he will explore ways to reduce the effects of estrogenic compounds in drinking water.
Endocrine disruptors work like biological disinformation campaigns. Sometimes mimicking natural hormones like estrogen, they alter normal hormone concentrations. The disruptors can either prevent or weaken the normal cell-signaling process. For humans, estrogensÂ– present in both males and femalesÂ– are the hormones responsible for female sexual features such as breast development and the menstrual cycle.
Rosenfeldt majored in chemical engineering and minored in environmental engineering in Washington University in St. Louis, Missouri. After college in 1999, he worked for two years as a project engineer solving a variety of industrial environmental problems at Environmental Resources Management, an environmental consulting firm. He came to Duke in 2001 to do his M.S. and then Ph.D.
"I feel like there is a natural lead-in from chemical engineering to environmental engineering, particularly in the treatment of chemicals. My work as an environmental consultant for two years after college solidified my interest in environmental engineering," he said.
The idea for Rosenfeldts research stems from his love for the environment. Describing himself as "a good steward to the environment," the Ohio native realized that endocrine-disrupting compounds had possible pernicious effects on the environment. These substances can affect hormonal systems in a manner that has adverse effects on the exposed organism or on its offspring. They include effects on embryos, gonads and reproductive behavior that can eventually lead to reduced reproduction and deterioration of not only quantity, but also condition of a population.
"Male fishes exposed to estrogenic chemicals in river water were found to produce proteins that only female fishes normally produce," Rosenfeldt said. "Alligators and turtles affected by a pesticide spill have deformed or undersized penises and the females have double the normal levels of estrogen. The list of environmental problems goes on and on. At this point the problem has only been linked in animals, but if you extrapolate that to human beings as animals, then it may be a problem for us in the future. This is something we must address, especially since it is a particular problem pregnant women and developing children who consume possibly contaminated drinking water."
For Rosenfeldts MS research, he used UV light in combination with H2O2 to destroy three endocrine-disrupting compounds: Bisphenol-A, Ethinyl Estradiol, and Estradiol. He then examined how fast the compounds degraded under UV light with H2O2, and modeled their destruction.
"These compounds have been found in high levels in streams and rivers all over the US, Europe and Japan," Rosenfeldt said. "Suppose youre a manager of a water treatment plant and you want to destroy these compounds. My model would allow people to see how fast these compounds would degrade if they were to include UV in their water treatment plan."
Rosenfeldt said that his Ph.D. research would deal with what these compounds would be turned into, and whether their byproducts would be as estrogenic as the initial product. For his Ph.D., he also wants to compare the UV/H2O2 process to the ozone oxidation process to see which is more energy-efficient for oxidizing chemical contaminants.
To facilitate his study of the comparison, Rosenfeldt traveled last November to the Swiss Federal Institute for Environmental Science & Technology (EAWAG).
"It was my first time to Switzerland," Rosenfeldt said. "I was given the privilege of working with some of the best scientists in the world, like Urs von Gunten, who is the head of the Water Resources and Drinking Water department at EAWAG. I learned a lot in those two months I was there, and it was an incredible experience. You would walk down the hall and be able to strike up a conversation with some extremely famous scientist. Whether that conversation was about science or skiing didnt really matter, you still came away learning something cool."
Rosenfeldt said that after he is done with his Ph.D. in 2006, he wants to be an environmental science or environmental engineering professor.
"The challenge for me would be to get the kids as excited about environmental engineering as I am. They might come in to my class thinking its just another course to trudge through, but there are some really interesting problems with the environment right now. These students are the future preservers of our environment and protectors of our health, and having the opportunity to teach them some of the tools theyll need for that task is very exciting."