Lydia Jennings

Soil, Water, and Environmental Science / College of Agriculture and Life Sciences

Defining biogeochemical indicators as tools to evaluate active mine reclamation strategies
Copper mining is a 4.6 billion dollar industry in the state of Arizona, and U.S. metal mines directly contributed $29.2 billion to U.S. GDP during 2011. While economically beneficial, metaliffeous mining can have adverse environmental impacts to soil and water quality, plant establishment and human health. Environmental remediation of mining sites is required in most countries, but can be a very costly process, with estimated costs to be between 1 and 2 billion US dollars per year in the United States. There is a need to improve mine reclamation technology in economical and practical ways. Waste materials at mining sites in arid environments, such as mine tailings and waste rock, are challenging for plant and microbial growth due to acidic pH, elevated salinity, low nutrients, and poor soil structure. Understanding the physico-chemical properties of mining waste that play a role in soil formation is an important first step to plant establishment. This project is a collaboration between four mining companies throughout Arizona and the University of Arizona to establish biogeochemical indicators for optimal re-vegetation strategies at modern copper mining sites. Electrical conductivity, pH, particle size distribution, total carbon, total nitrogen, total organic carbon, total sulfur, neutrophilic bacterial plate counts, substrate net acid producing potential and molecular biology detection of soil bacterial populations will all be assessed as gauges of soil health. Using these parameters, our goal is to develop bio-indicator criteria for the re-vegetation of participating companies.