In the more than two months since the Jan. 9 chemical spill into West Virginia's Elk River, new findings reveal the nature of the chemicals that were released into the water and then into the air in residents' houses.
"Based on our increasing understanding of the chemicals involved in the water crisis, the complexities and implications of the spill keep growing," said Andrea Dietrich (http://www.cee.vt.edu/people/dietrich.html), professor of civil and environmental engineering at Virginia Tech. "People are still afraid to drink the water; odors persist in schools, residences, and businesses; data are still lacking for the properties of the mixture of chemicals in the crude MCHM that spilled."
The lack of data motivated Dietrich and her research team to take on essential odor-related research that went beyond their National Science Foundation Rapid Response Research grant to better understand the properties of the chemical mixture called crude 4-methylcyclohexane methanol, the major component in the crude mix of the spilled chemicals into the Elk River. It is used in the separation and cleaning of coal products.
Rapid Response grants are the agency's funding mechanism when a severe urgency exists in terms of the availability of data.
When Dietrich's team first started, their goal was to conduct detailed scientific investigations to determine the long-term fate of the chemicals in the drinking water distribution system and in the environment. The spill had occurred upstream from the West Virginia America Water intake, treatment, and distribution center. Some 300,000 residents were affected, losing their access to potable water. The continued plight of West Virginia living day-to-day with the contaminant's licorice odor resulted in Dietrich's team unraveling the odor threshold problem.
As the ban was lifted on drinking water use, Virginia Tech researchers gathered their data and they realized that West Virginians were still complaining of an odor in their homes and in the environment.
"Like for many contaminants in water, chemicals leave the water and enter the breathing air, so that inhalation becomes a route for human exposure as well as drinking the water," stated Daniel Gallagher (http://www.cee.vt.edu/people/gallagher.html), also a faculty member in Virginia Tech's Via Department of Civil and Environmental Engineering and a member of the research team.
The Virginia Tech researchers were able to pinpoint the concentrations of contaminants in the air that residents can detect because they have specialized equipment, uniquely available in the College of Engineering, but more commonly used in the food, beverage, and fragrance industries. Called olfactory gas chromatography, it allows the investigators to independently measure the concentrations and odors of the two isomers found in the 4-methylcyclohexane methanol.
This specific cyclohexane "consists of two isomers, a cis- and a trans- methylcyclohexane methanol. The isomers have the same chemical formula but a very slight shape difference that for many isomers, can have enormous effects on the physical, chemical, and biological properties. Only the trans isomer has the characteristic licorice-like odor. The cis isomer is significantly less odorous and has different descriptors," Dietrich explained.
Dietrich added that they determined the odor threshold concentration of the trans-isomer to be "exceedingly low", measured at 350 parts per trillion by volume in the air. This air odor threshold can be combined with a Henry's Law Constant that relates the concentration in air to estimate the corresponding concentration in water. Based on an estimated Henry's Law Constant from TOXNET, this odor threshold in water concentration is about seven parts per billion-water.
This is more than a hundred times lower than the one part per million health guideline recommended by the Center for Disease Control. Thus, the odor of MCHM is readily detectable even when the water concentration water meets the health guideline level.
This relationship now needs to be further understood through additional data collection and research.
An "important implication of the findings," Dietrich said "is the critical need to independently measure the concentrations of the cis and the trans isomers, as was done in this study and is being done at the Virginia Tech labs. "The licorice odor will be proportional to the amount of the trans isomer, not the total amount of methylcyclohexane methanol. While there may be a tendency to measure 'total methylcyclohexane methanol', this could lead to misleading interpretations."
"The cutting edge research instrumentation and support available for student and faculty research is extensive," said lead graduate student Katherine Phetxumphou of Woodbridge, Va., who is supported on a Virginia Tech Graduate school fellowship and is a member of Virginia Tech's Water INTERface Interdisciplinary Graduate Education Program (http://interdisciplinary.graduateschool.vt.edu/?q=node/14).
"After our research protocol for human subjects received approval in February, we logged hundreds of hours of research that all boiled down to one number -- the odor threshold for trans methylcyclohexane methanol. It is amazing we accomplished so much so fast; we were committed to do this for the people of West Virginia and the research community," Dietrich said.
Of all the human senses, odor has been the most difficult to scientifically explain. Just 10 years ago, Linda Buck and Richard Axel were awarded the Nobel Prize in Medicine for being the first to decipher the genes that determine the sense of smell.
Dietrich is an expert on water quality and treatment, as well as its taste and odor assessment. Several years ago, the American Water Works Association and Research Foundation sponsored Dietrich to travel around the U.S. to educate utility staff and managers on how to use sensory analysis to detect changes in water quality. She is also a co-developer of three odor-testing methods for the daily monitoring of raw and untreated water. She is the current chair of the International Water Associations' Specialty Group for Off-Flavors in the Aquatic Environment; she travels internationally to speak and train on detecting tastes and odors in drinking water.
The College of Engineering (http://www.eng.vt.edu/) at Virginia Tech is internationally recognized for its excellence in 14 engineering disciplines and computer science. The college's 6,000 undergraduates benefit from an innovative curriculum that provides a "hands-on, minds-on" approach to engineering education, complementing classroom instruction with two unique design-and-build facilities and a strong Cooperative Education Program. With more than 50 research centers and numerous laboratories, the college offers its 2,000 graduate students opportunities in advanced fields of study such as biomedical engineering, state-of-the-art microelectronics, and nanotechnology. Virginia Tech, the most comprehensive university in Virginia, is dedicated to quality, innovation, and results to the commonwealth, the nation, and the world.
This story can be found on the Virginia Tech News website: http://www.vtnews.vt.edu/articles/2014/03/032714-enginieering-chemicalsinair.html
Lynn A. Nystrom | VT News
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
Disarray in the brain
18.12.2017 | Universität zu Lübeck
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
22.01.2018 | Materials Sciences
22.01.2018 | Earth Sciences
22.01.2018 | Life Sciences