CHARACTERIZATION OF BACTERIAL MANGANESE REDUCTION IN ABANDONED COALMINE DRAINAGE THAT CONTRIBUTES TO THE RE-MOBILIZATION OF POLLUTANTS

In Pennsylvania, there are ~11,000 abandoned mines that pollute the environment. Passive remediation systems are constructed to treat abandoned mine drainage (AMD), designed to increase the pH and precipitate metals onsite. High levels of manganese (Mn) can cause staining, damage to water infrastructure, neurological deficits in children, and Parkinson-like symptoms. Passive systems are naturally colonized by microbes that can impact the remediation within these systems both positively and negatively. We have determined that in acidic AMD, manganese reduction is primarily geochemically based on pH. Whereas, in neutral AMD, manganese reduction can be microbially driven. However, the microbial mechanisms that contribute to this are poorly understood and characterized. Microbes that impact Mn reduction have been isolated using differential manganese reduction media as agar and broth. Despite manganese reduction in acidic systems being based on geochemistry, manganese reducers were detected in all ponds of the system. Manganese reducing isolates were identified via 16S sanger sequencing and whole genome sequencing. Within the neutral system of Wingfield Pines, the frequency of manganese reducers was determined using differential broth. Determining the microbial metabolism and genes involved in the resolubilization of manganese is of interest for biomonitoring system health, to determine what if any interventions can be done to slow or stop microbial driven manganese resolubilization, as well as future applications for biomining of AMD.