Jun
24

Arsenic and Coal Trains

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A view of a coal-bearing railroad car through the vegetation at a test site.

Summer (in the astronomical sense) has just begun, and my Honors project, Land Use Impacts on Heavy Metal Accumulation in Vegetation, is three weeks underway. My hypothesis for this project is that various land uses, particularly the transport of loads of coal through the city of Williamsburg from Western Virginia to the ports at Hampton Roads, lead to the accumulation of heavy metals and other harmful elements in the adjacent ecosystems. John Lovette, a fellow chemistry/environmental science student, conducted a thesis last year exploring this topic, primarily assessing mercury accumulation in wetland environments near the tracks. Because the study of pollution impacts on ecosystems is so complicated, there was a lot more to explore where John left off, and I was eager to continue the investigation. Currently, I am testing for metal accumulation in vegetation. Trees absorb a great number of toxic compounds from the atmosphere as well as from the soil, and can serve as a valuable proxy for air quality.

I am excited about this project both for its context and its content. I have been engaged with environmental issues in various capacities throughout the past few years, and have take both a personal and a scientific interest in understanding and preventing the pollution that occurs as a result of extractive fossil fuel industries. While a great deal of research is on the books demonstrating the harmful ecological and health impacts of coal mining and combustion, few researchers have probed the intermediary section of the coal cycle – the transport from mining source to shipping destination. The opportunity to study the impacts of the coal cycle so close to home was one I was excited to explore.

Since I proposed my research project, this issue has gained more attention among scientists and among the public. Coal companies in the Pacific Northwest have proposed the expansion of their export terminals, which increase coal traffic through the region.  These proposals have lead to a surge in scientific interest and opposition from Northwest tribes, local governments, and environmental groups. The Municipal Research and Services Center of Washington has a great deal of information on the issue at their website.

A sample test site: A loblolly pine branch overhangs the railroad tracks

A sample test site: A loblolly pine branch overhangs the railroad tracks

In terms of content, this project represents the culmination of my studies at the College in environmental science and chemistry, and so far, it is everything I could have asked for: complex, multifaceted and challenging. On my first day of research, I found myself out in the field, scrambling along railroad tracks and sometimes running to avoid trains.  It’s nice to pursue research that includes some degree of physical activity, since I’m someone who gets restless before too long if I am stuck at a lab bench or in a library.

The bench aspect of the project has presented its own challenges. While I hope to test a few more metals, so far, I have been focusing on two elements – arsenic, a well-known environmental toxin, and selenium, which has toxic properties above a very narrow range of biological necessity. I will be using a method called Hydride Generation Atomic Absorption Spectrometry (HG-AAS) to measure levels of selenium and arsenic. The HG-AAS process converts these elements to a vapor, which is then excited by light at a wavelength corresponding to the element in question. The extent of absorption is proportional to the concentration of that element. You might be able to guess that I can’t just throw a sprig of Loblolly Pine into the HG-AAS instrument; the organic matter has to first be broken down. For this, I am grinding my pine needles to a fine powder (a very fragrant process!) and digesting them with a combination of nitric acid, hydrogen peroxide, and UV light. If my preliminary results from this method are promising, I may be on my way to taking my first HG-AAS readings by the end of the week!

My excitement about this project continues to build as I see more and more press about the potential impact of coal-bearing trains on environmental quality. I also want to give a shout-out to the donors who are making this project possible. Around the time that I found out I was fully funded for the project, I read this article about Dr. Dan Jaffe, a University of Washington atmospheric chemist who was denied government funding to study the impact of coal trains on air quality and human health, and turned to crowd-sourcing to fund his research. Due to industry lobbying, it can be incredibly difficult to fund research that investigates the health impacts of industrial practices, which makes grants and donations like the ones I am working from so crucial to increasing our understanding of the coal cycle’s impact on the environment. It’s an honor to take part in this field of research, one I plan to pursue in graduate school and (perhaps) beyond.

Until next time,

Sharon