Patterns in utilization of carbon sources in soil microbial communities contaminated with mine solid wastes from San Luis Potosi, Mexico

• Published in: Ecotoxicology and environmental safety Vol. 208; p. 111493
• Main Authors: Martínez-Toledo, Ángeles, González-Mille, Donaji J., García-Arreola, Maria E., Cruz-Santiago, Omar, Trejo-Acevedo, Antonio, Ilizaliturri-Hernández, César A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15.01.2021; Elsevier
• Subjects: Bacteria - metabolism; Carbon - metabolism; Community level physiological profiles; Heavy metals; Historical mining activity; Metalloids - metabolism; Metals, Heavy - metabolism; Mexico; Mining; Pollution indexes; Soil Microbiology; Soil Pollutants - metabolism; Mexico; Community level physiological profiles; Pollution indexes; Heavy metals; Historical mining activity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2020.111493

In San Luis Potosí, Mexico, the exploitation of minerals has historically been carried out as an activity that has left in its path environmental liabilities, with high concentrations of heavy metals. These metals have undergone weathering by rain and wind and have moved closer to inhabited locations as is the case of Cerro de San Pedro (CSP) and Villa de la Paz (VDP). The objective of this study is to show the biological alteration of soils due to the presence of heavy metals and metalloids like Cadmium (Cd), Copper (Cu), Lead (Pb) and Arsenic (As) and to find the relationship between contamination and risk indexes. Soil samples were obtained from sites with historical records of mining activity and their surroundings. Several analyses were performed, such as pH levels, organic matter, electrical conductivity, clays, heavy metals and As. Moreover, Community Level Physiological profiling (CLPP) were conducted. The obtained evidence showed high levels of contamination by As and heavy metals in both sites (CSP: 6485.1 mg/Kg of Pb and pH of 4.4; VDP: 7188.2 mg/Kg of As and pH of 7.8). According to the Metal Pollution Index (MPI), 607.0 in CSP and 1050.5 in VDP, presented a high environmental risk, apart from, risk to human health (SQGQI) 35.8 in CSP and 131.5 in VDP. At the same time, CLPPs showed that microbiological communities were selective in taking up substrate groups, in the following order: Carbohydrates > Polymers > Carboxylic acids > Amino acids > Amines/Amides. However, a positive correlation in CSP was only found between both indexes and Amines/Amides (r = 0.46, p < 0.05), and in VDP the D-Galactonic acid-γ-Lactone with the MPI (r = 0.49, p < 0.05), and with the SQGQI (r = 0.45, p < 0.05). Although this behavior was not homogeneous, it was possible to find negative correlations between both indexes and the AWCD with other substrates, influenced by the physicochemical characteristics presented in each studied site. Consequently, according to our findings, a combined effect between the physicochemical characteristics, As, and heavy metals took place, on the metabolic activity, causing alterations to soil functions. •Soil contaminated with mine wastes has high concentrations of toxic elements compared to the reference sites.•As and heavy metal concentrations in contaminated sites represent a high potential risk for human and environmental health.•Long-term contaminated enviroments altered the metabolic activity and physicochemical properties in soil.•Substrate consumption assays are useful to study physiological responses of microbes in these environments.