Our work seeks to differentiate between biological and abiotic mechanisms for adsorption/treatment of As and U in mixed metal environmental systems for bioremediation applications.
Specific Objectives include:

Objective 1: Determine As and U speciation and rate of adsorption onto fungal biomass/hyphae using batch experiments at pH 4 and 7 under surface oxidizing conditions using geochemical modeling, spectroscopy, microscopy and microbiology tools. 

Objective 2: Characterize functional group surface chemistry and surface charge of abiotic biopolymers (active and inactivated fungi) reacted with metal mixtures (2 ppm U and As) using FTIR and XPS under same batch experimental conditions.

Objective 3: Integrate HPTF-LC, XPS, and microscopy tools to identify fungal secondary metabolites produced after reaction of Fusarium sp. with Uranyl (2 ppm and 0.2 ppm) using batch experiments at pH 7 and 4.

Team Leads: Jeffrey Bartholomeusz, Chrisa Whitmore, Gwen Flores

This work in environmental science and engineering (EES) seeks to synthesizing ethical protocols, data practices, and governance as we build partnerships with Indigenous communities for research, education, and outreach programs.

The objective of this work is to highlight concepts and frameworks from a growing community of interdisciplinary researchers seeking to implement and create tools which are tailored towards working with Indigenous communities. We use an iterative and cumulative seasonal framework to help expand the EES conceptions of data organization, sharing, and generation to include non-human specimens and samples from laboratory to ecological scale. We have associated each Earth season to a set of existing frameworks (CARE, TRUST, FAIR, and SHIFT) which have been developed to critically assess how research programs are planned, implemented, and utilized. We provide suggestions based on our findings on integrating relational accountability into research practice for investigators to become data stewards. Our hope is to engage with and elevate the implementation of Indigenous data sovereignty in environmental engineering and science research efforts. 

Team Leads: Jariah Callado, Cherie De Vore

Hydroponic and soil investigations are being explored to measure beneficial root-dwelling fungi (endophytes) affecting metal (Cu and As) uptake, accumulation, and tolerance. This work aims to better understand how these natural plant–fungus relationships can be used to manage mixed metal contamination, particularly in rural AZ and SW mining legacy areas, where metals have been a long-standing community concern.

De Vore’s early findings suggest that pairing native plants with filamentous fungi could be a promising low-cost, nature-based approach to manage metals in contaminated environments. Such plant–fungus systems could be applied in risk reduction strategies, helping protect ecosystems and communities. Further research in soil environments is needed to refine how these partnerships can be used for effective bioremediation.

Team Lead: Xavia Gutierrez

The copper mining industry is the focal point of numerous environmental debates in the Southwestern United States. Communities face disproportionate health and environmental impacts due to the pollution of soil and water with heavy metals originating from mining activities. Some of the primary heavy metals associated with copper mining include copper, zinc, lead, arsenic, and cadmium. Research efforts have focused extensively on exploring innovative and sustainable remediation solutions. One promising approach for remediating heavy metals and mine wastes is a bio-mediated technology known as mycoremediation, which primarily focuses on mushroom forming fungi.

Our objective for this study is to identify the metabolic processes that allow P. pistillaris to tolerate and accumulate heavy metals found in copper mine wastes, namely copper, zinc, lead, arsenic, and cadmium. We utilize microbiology techniques, ion chromatography, and metabolomic/proteomic assays to understand how P. pistillaris response to heavy metal stress and intracellular mechanisms conducive to remediation. The novelty of this study is the identification of species-specific heavy metal tolerance mechanisms in a mushroom-forming fungus native to a desert environment. Although many previous studies have explored biotic mechanisms for heavy metal remediation in mushroom-forming fungi, few have considered how those mechanisms may vary in fungi adapted to more strenuous conditions, such as those found in deserts. Investigating P. pistillaris and its biotic responses to heavy metal stress can support the creation of a framework for developing heavy metal mycoremediation strategies in arid and semi-arid environments.

Team Lead: Ryan Cotter

The primary objective of this project is to investigate the potential of Fusarium sp., a metal-tolerant fungus, as a biological agent for removal of copper and arsenic from mining-influenced water (MIW). Specifically, we aim to assess the biosorption capacity (mg/g biomass) and adsorption rates (min-1) of metals in the presence of a mixed metal solution containing copper (Cu), zinc (Zn), manganese (Mn), and sulphate (SO4-2), which simulates the composition of MIW. To achieve this, we have developed robust batch experiments that replicate the pH values, surface oxidizing conditions, and chemical composition expected in our passive treatment system to evaluate the effectiveness of Fusarium sp. in removing arsenic and the other metals. This includes quantifying removal efficiencies (%), adsorption kinetics (min-1), biosorption capacities (mg/g biomass), and determining the best-fit isotherm. Based on these results, we will optimize the large-scale passive remediation system by determining the volume and residence time of the fungal treatment cell, assessing the functional lifetime of the fungi, evaluating general adsorption mechanisms, and determining if further treatment is needed after the fungal cell to meet EPA Maximum Contaminant Level (MCL) standards for treated effluent. 

 This solution provides a long-term method for mitigating water pollution while empowering affected communities with accessible and low-maintenance water treatment technology. 

Team Lead: Macy Winn

The objective of this project is to integrate laboratory batch experiments to evaluate the effect of pH (4 and 7) on complexation and precipitation reactions with 2 mM uranyl and arsenate mixtures, in the presence of 1 mM phosphate, an environmentally relevant anion. This effort serves as a physiochemical comparison for other biotic systems tested in the Nihi Lab. Circumneutral pH facilitates the precipitation of apatite and Ca(PO4) minerals that could lead to co-precipitation with arsenic and the formation of CaCO3-U bearing minerals.

Uranium phosphate minerals could be precipitated in acidic pH conditions. In both pH conditions, the presence of phosphate leads to more adsorption/precipitation reactions in the metal mixture systems. 

Team Lead: Ignacio Garcia

This work seeks to address heavy metal accumulation in plants from Serpentine and Non-Serpentine Wildland Soils and Implications for Wildfires.

Objective: Evaluate metal (Cr, Ni, Mn) accumulation in plants from serpentine and non-serpentine wildland soils pre (Phase 1) and post fire (Phase 2). This work is followed by a controlled burn to determine changes in microbial diversity, richness and abundance in response to low severity burns.

Team Lead: Cherie De Vore