Active and diverse microorganism communities are essential for soil; and hence for agriculture, food security, and ecosystem health. Changes in these communities can significantly influence soil quality, health, and productivity. This research uses experimental and statistical/modeling approaches to investigate and predict the impact of common metal nanoparticles (iron, copper, and silver), which are reported to have anti-microbial properties, on soil microbial communities. The main research goal is to develop models that can help assess the ecotoxicity of common metal nanoparticles without having to resort to carrying out large numbers of experiments for each sample to be tested. This work accomplishes that goal with a combined experimental/modeling approach. Experiments involving the study of the toxicity of ten important soil parameters (pH, temperature, nanoparticle concentration, organic carbon content, soil moisture, and the concentration of various cations and anions like Na, Ca, Mg, nitrates, and phosphates) on the interaction between selected commercially purchased nanoparticles and two model soils, each with their unique microbial community, will be carried out in microcosms. The toxicity of the nanoparticles to microbial communities will be evaluated using three different indicators of microbial health and metabolic activity: PCR-DGGE, Biolog Ecoplates, and total soil FAME analyses from which a single ecotoxicity value can be determined. Results of the experimental matrix will be used to develop a linear regression model that will identify environmental parameters that increase, decrease, or have no influence on toxicity on the soil microbes. A quadratic regression will be developed that build off the results of the linear model to predict the toxic potential of each parameter and identify and assess interactions among the various environmental parameters. Broader impacts of the research include the strong integration of research and education, engaging large numbers of undergraduate students in environmental biology research, and using the research to augment undergraduate course curriculum. Through a summer research experience, the project will also engage students from Southern University, a historically black college that is still recovering from the effects of Hurricane Katrina. Participation of under-represented groups in the sciences will also be increased by recruiting students from the Dowling College Center for Minority Teacher Development and Training Program to participate in the research. Free public lectures tailored for the general public to increase their awareness of their impacts on the environment will also be presented.
