New Mexico Geological Society Annual Spring Meeting — Abstracts

Basalt rock dust holds promise for several beneficial applications, including its use as an alternative fertilizer or a carbon sequestration agent. These uses are closely linked to the rock's weathering behavior, which can potentially release environmental contaminants originating either from natural sources or mining activities. Therefore, it is crucial to assess the leaching of such contaminants during application to prevent environmental pollution. In this study, basalt rock dust sourced from New Mexico was examined to evaluate its suitability for land application. The samples were categorized based on their physical portion (interior, exterior, and powdered) and particle size (150–75 µm and <75 µm). The samples underwent mineralogical and chemical characterization. Mineralogical analysis revealed that the primary constituents were anorthite, augite, sanidine, and quartz. Chemical analysis indicated the presence of elevated levels of aluminum, magnesium, calcium, iron, manganese, sodium, and trace amounts of heavy metals, including arsenic, cadmium, chromium, and lead. Subsequently, leaching tests were carried out to assess the potential environmental impact. Inorganic species in the leachates were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES) and ion chromatography (IC), while organic compounds were assessed using total organic carbon (TOC) analysis and fluorescence excitation-emission matrix (FEEM) spectroscopy. The leachate analysis showed detectable levels of lead, though no other significant concerns were identified. TOC results indicated a minimal presence of organic matter, and FEEM spectra confirmed low concentrations of fulvic and humic substances. These findings suggest a reduced likelihood of heavy metal and organic pollutant mobility in water and soil due to adsorption and retardation effects. Overall, the results suggest that the basalt rock dust from New Mexico does not pose significant environmental risks. However, some minor issues should still be considered before its widespread use as a fertilizer alternative.