By Lisa Scott, MS in Environmental Science and Policy student
This semester at Plymouth State University (PSU), my Contaminant Hydrology class had the opportunity to transform a group project on the abandoned Ore Hill mine site into a report for the US Forest Service (USFS). The Ore Hill site is located in the town of Warren, New Hampshire, and was mined for metals from the late 1800s through the early 1900s, before its abandonment in 1915. Acid mine drainage containing high metal concentrations seeping from the site have contributed to unknown ecological impacts overtime. In 2006, the USFS took steps to improve mine site conditions through physical removal of mine tailings and installation of remediation systems on site.
We visited the Ore Hill mine in late September 2014 to assess site conditions. Our visit was extremely valuable for visualizing the site layout and observing water and contaminant flowpaths. We saw building debris where the old mine had existed, and the drip pipe where the contaminant source persists. As we observed the layout of the site (Slopes, flowpaths, culverts, and vegetation) we were able to see how contaminants move through the system rather than imagining based on reading old reports.
Our class focused on two of the main contaminant removal systems on site: the bioreactor and wetlands. The bioreactor acts as a settling pond to help metals fall out of solution from inflowing water before it is discharged to the lower portion of the site. Although the term “bioreactor” may sound like a deadly experimentation device from a SciFi movie, it is simply used to increase the amount of time metals have to be separated from flowing water.
The second removal system we looked at were the wetlands at Ore Hill. Increased vegetation is often used as an effective contaminant removal system. Phytoremediation is a common term used to describe plants’ ability to uptake contaminants, such as metals, and improve land and water quality. Wetlands have the added benefit of being high in organic matter and low in oxygen. These conditions promote additional metal removal by causing metals to precipitate out, or come out of the water solution.
To assess the effectiveness of the two contaminant removal systems, we used data collected by the USFS and PSU grad students from the years 2007-2013. We found that the data suggests that the bioreactor and wetlands have been successful at removing concentrations of lead, cadmium, aluminum, copper, and zinc. In other words, efforts by the USFS to decrease concentrations of potentially harmful metals leaving the Ore Hill site has led to an improvement in the water quality discharge overtime.
The most enduring lesson we learned working on this project was that raw data is often filled with errors and is difficult to interpret. Our conclusions were broad, but useful nonetheless. This project was engaging and motivating with the pressure of reporting our results back to the USFS. I really appreciated applying course work to a professional working experience, and feel a sense of accomplishment with the completion of this project.