NMSU Graduate Student Investigates the Use of Plants to Remove Contaminants from the Gold King Mine Spill of Wastewater Into the Animas and San Juan Rivers

By Catherine Ortega Klett, NM WRRI Program Manager

Jason Fechner is a graduate student in the NMSU Department of Plant and Environmental Sciences. He graduated in May 2018 with a BS in horticulture from NMSU. Jason received a 2018 NM WRRI Student Water Research Grant entitled: Gold King Mine Spill: Contaminant Removal of San Juan County Rivers via Phytoremediation.

The Gold King Mine Spill in 2015 contaminated the Animas and San Juan Rivers with heavy metals that affected multiple states including Colorado, New Mexico, and Utah. This event had a tremendous impact on local farmers dependent on the Animas and San Juan Rivers for irrigation of their crops. There are also health concerns related to the plant and aquatic life in and around the contamination sites. Due to these concerns, remediation of these contaminated mining sites and river stretches is a priority issue. The main objective of this project is to explore the use of selected plants and their associated microbes for the removal and/or stabilization of contaminants deposited by the mine spill event. In this effort, Jason is working under the guidance of his faculty sponsors Dr. April Ulery, Department of Plant and Environmental Sciences, and Dr. Soum Sanogo, Department of Entomology, Plant Pathology, and Weed Science at NMSU.

Common duckweed (Lemna minor) is the plant chosen for this remediation project, as it is found throughout the United States and is known for its remediation ability as well as its high reproductive rates. It is an aquatic plant that grows on still or shallow, slowly moving waterways, and it is known to tolerate water contaminated with various toxins. For the Gold King Mine spill, there are multiple heavy metal contaminants of interest; however, the focus of the present study is the uptake of iron. Iron is one of the principal contaminants carried by the spill, and while it can be very toxic in high doses, it is also of interest because of its ability to form stable complexes (chelates) with other, more toxic contaminants. Accordingly, the focus of this project is to determine the extent to which duckweed is able to remove iron from an aquatic system. An attendant goal is the identification of bacterial and fungal species that are associated with the duckweed and may be partially or largely responsible for the chelation of iron.

To date, duckweed has been grown in various small vats under controlled conditions of lighting as well as nutrient and iron concentrations. Associated bacterial and fungi cultures have been isolated, grown, and samples analyzed using the genetic multiplication process known as polymerase chain reaction (PCR). The study results indicate that three different species of fungus are present, including Alternaria alternata, Plectosphaerella cucumerina, and Cladosporium tenuissimum. A review of the literature suggests that Alternaria alternata is most likely responsible for the plant’s iron uptake ability, as it can mycosynthesize iron nanoparticles.

A future, additional avenue of research for this project will include setting up the experiment again, but on a larger scale, composting the duckweed once the experimental trial is over, and growing Pleurotus ostreatus (oyster mushrooms) using the duckweed compost. The oyster mushrooms will be analyzed to see whether the fruiting bodies have absorbed any of the iron. If they do absorb iron, there will be an effort to determine how much is absorbed, how much is bound in the compost, and how much may have precipitated out of solution.

Knowledge of what types of plants can be used to remove or stabilize spill contaminants could prove very beneficial for water research and environmental agencies, especially since this approach is environmentally friendly, relative to conventional remediation methods. It is also potentially very cost effective, since it would reduce the burden of removal of contaminated material.

A native of Alamogordo, NM, Jason indicated that the NM WRRI grant has afforded him the opportunity to work with other scientists and to get their perspective on similar research. He has also been able to observe other field research studies underway on the Gold King Mine spill. He said, “The grant has provided funding for laboratory and other supplies pertaining to my research. After completing a master’s degree, I plan to continue my education and obtain a PhD. Eventually I want to work for a research university where I can train the next generation of scientists in the classroom and the lab.”