Evaluation of the content of metals and contamination indices generated by environmental liabilities, in Tacna, Peru

Abstract

Abandoned mines are environmental liabilities with a high potential for contamination of rivers, soils, and entire ecosystems, which constitutes a threat to wildlife, flora, and fauna, in addition to socio-environmental, economic, and human health risks. The objective of this study was to determine the degree of contamination of 5 abandoned mines to evaluate their potential environmental and social impact. The presence and concentration of arsenic, barium, cadmium, lead, chromium, mercury, and free cyanide by mass spectrometry, and hexavalent chromium by ion chromatography. The environmental indices of geoaccumulation, contamination factor, and contamination load were used to evaluate the level of contamination for each area. The results showed high contamination with a high content of arsenic (2,046 mg Kg− 1), cadmium (650 mg Kg− 1), lead (26,131 mg Kg− 1), free cyanide (92 mg Kg− 1), mercury (26.4 mg Kg− 1) above the established maximum limits, not detecting the presence of hexavalent chromium (0.03 mg Kg− 1). In Peru, there are many abandoned mines, so it is a latent danger of an environmental disaster. Therefore, it is essential to assess heavy metal contamination together with environmental risks, to establish efficient mitigation measures.

Cyanide Bioremediation by Bacillus subtilis under Alkaline Conditions

“…Cyanide is a highly toxic compound to living organisms that is used in various economic activities, mainly related to mining [73,74]. These mineral extraction activities generate wastes contaminated with heavy metals or toxic substances like CN that disperse into the environment [13,75]. This study isolated eight bacterial strains from a soil sample with sulfur mining residues that could tolerate 50-1000 ppm CN under alkaline conditions (Figure 1).…”

“…Studies have detected high levels of cyanide contamination in different rivers in Tumbes [11], Tacna [12,13], Amazonas [14], Piura [15], Arequipa [16,17], and other regions in Peru, likely originating from legal and illegal mining operations [18].…”

“…The Tacna region in Peru faces several environmental liabilities left behind by abandoned informal mines where various materials, including cyanide, were used for gold, copper, and sulfur processing, reaching concentrations of up to 92 mg/kg of free cyanide in the Cano community [13]. These sites are located close to rivers, leading to risks of water contamination that could have negative effects on the environment and health of people consuming the polluted water [13].…”

Effect of Lyoprotective Agents on the Preservation of Survival of a Bacillus cereus Strain PBG in the Freeze-Drying Process

“…The PBG strain stands out due to several outstanding features. First, it originates from environments affected by mining activities related to copper extraction, resulting in the presence of contaminants such as arsenic, lead, cadmium, barium, chromium, mercury, and free cyanide [18]. Secondly, it demonstrates remarkable tolerance to concentrations of up to 500 ppm of cyanide (CN − ).…”

“…Globally, there are over a million abandoned mines [15][16][17], and Peru is no exception to this issue. In the Tacna region, mining legacies from the Chulluncane copper mine contain high levels of contamination, with 1102 mg/kg of arsenic, 620.33 mg/kg of lead, 27.83 mg/kg of cadmium, and 0.04 mg/kg of free cyanide (CN − ) [18].…”