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Why such low Mn levels near EMI?. Figure 2. Graphs on the left are from Bender Road (closet to EMI) and graphs on the right are from the control. Why are bark levels of Mn elevated?. Figure 3. Graphs represent the unpredicted high levels of Mn throughout bark samples.
Figure 2. Graphs on the left are from Bender Road (closet to EMI) and graphs on the right are from the control.
Why are bark levels of Mn elevated?
Figure 3. Graphs represent the unpredicted high levels of Mn throughout bark samples.
Sugar Maple: Good Bioindicator?
Figure 4. Top graphs show the difference between the Sugar Maple at Bender Road and the control. The bottom graph shows the trend in Mn levels from 1978-2008 at the Bender Road site. Average values of the east and west samples are plotted in a line graph; the low R2 value suggest that there is no statistical trend in Mn levels.
In 2000, Senator Mike Dewine petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to determine if air pollution was adversely affecting the health of Washington County residents.1 With only one air monitor in place, the ATSDR asked the Environmental Protection Agency (EPA) for assistance. Between 2000 and 2007 the EPA put five total suspended particulate air monitors in place throughout the Ohio valley.1
Examination of these monitors revealed abnormally high levels of Manganese (Mn) throughout the ambient air, particularly near Eramet Marietta Inc. (EMI), a world leading producer of ferroalloy Mn hardeners for metals.
Mn is a natural heavy metal found throughout the human body in small amounts. In the body, Mn acts as a required cofactor for arginase, which produces urea in the liver.2 Acute and chronic over exposure has been attributed to a build up of Mn in the brain, particularly in the globus pallidus and substantia nigra.5 This buildup can lead to symptoms much like that of Parkinson's disease.
In the environment Mn is also found naturally, aiding in the transport of nutrients throughout plant material. A lack of Mn can lead to deficiency symptoms resulting in leaf pigment malformation and total biomass loss.3
I hypothesized that my findings would show proportional levels of Mn concentrations in tree ring bore samples taken near the EMI facility as the ATSDR found through their air monitoring data. Also, I predicted that tree rings will show historic trends in Mn levels, particularly after 1951 when EMI began production.
Figure 1. Arrow closest to EMI was located off of Bender Road at property owned by Kris Marr Reality. The second sample site is located directly across from the Washington County Career Center and is also property of Kriss Marr Reality. The control site is located in Ashland County at private property in the middle of the Mohican State Park. This is displayed in the map of Ohio in the right hand corner.
Based on a ATSDR emission model, two test sites and one control site were chosen in regards to EMI. These locations can be seen in figure 1. At each site two tree ring core samples were excised from the angiosperm species White Oak (Quercus alba), Yellow Poplar (Lireodendron tulipifera), and Sugar Maple (Acer sacchrum) and the gymnosperm species White Pine (Pinus strobus). These species were chosen based on abundance in each location and from the literature of Kennedy and Bergeron.4
Samples were excised from each species with a 16’’ Suunto increment bore. The diameter of each tree was also recorded and one inch square bark samples were removed from the area of excision.
In the lab, core samples were sanded and divided into five year segments. The bark samples were also divided into three sections. All samples were then dried and weighed to determine dry weight. Degradation of the wood was accomplished by adding a volume of Nitric acid 20 times the amount of the samples dry weight. Samples were allowed to reflux fully, then a volume of Perchloric acid 4 times the dry weight was added.
Samples were dried to approximately 1 ml of solution and then brought to a final solution of 10 ml with 2% Nitric acid. Final solutions were filtered and analyzed with flame atomic absorption spectroscopy. Mn concentrations were determined based on a standard curve ran with every trial.
I would first off like to thank Dr. David McShaffrey for all of the support, advice, and knowledge he gave me throughout this entire experience. Secondly, I would also like to thank Dr. David Brown for his help with the sample degradation and analysis and for also putting up with me always being in his way in the lab. Next, I would like to thank Dr. Fitch, Caroline Beidler and the Neighbors for Clean Air, and Patti Finkel with Kris Marr Reality for all of their help in the long process of finding an adequate test site. Finally, I would like to thank my fellow capstone classmates and Dr. Spilatro and Dr. Lustofin for their guidance and support throughout my capstone project.