Environmental risk assessment of technosols formulated with calcined pyrite-rich coal gangue
摘要
Calcination was used to oxidize and reduce the sulfur content of pyrite-rich coal gangue (PCG). The resultant ash (CCG) was used as the main compound (95–100%) of Technosols. A balance was produced using composted urban solid waste (USW) as the organic matter (OM) source. Ecotoxicological assessments were performed by monitoring antimicrobial activity in Escherichia coli, growth and dry biomass production of Avena strigosa Schreb, and the avoidance behavior and feeding activity of Eisenia fetida. Calcination increased the pH from 2.67 in PCG to 4.88–5.87 in formulated Technosols, reducing the potential for acid mine drainage (AMD) formation and its consequences. Al, Fe, and Mn availabilities were reduced from 187.4, 826, and 6.2 mg·L− 1 to values above the detection level. The leachates from the presented Technosols did not demonstrate an inhibitory effect, whereas those from PCG considerably inhibited E. coli activity (25 ± 3). An ANOVA test for A. strigosa resulted in an F-value of 102.73 with a p-value of 5.01 × 10− 22 for growth, an F-value of 25.7 with a p-value of 3.04 × 10− 5 for dry biomass production; the ANOVA for E. fetida testes resulted in F-value of 7.76 and p-value of 9.39 × 10− 3 for avoidance behavior, and F-value of 96.53 and p-value of 6.02 × 10− 8 for feeding activity. These results indicated that elevated pH and OM content are essential for improving the quality of Technosols. This study highlights the importance of integrating physicochemical and biological approaches to develop sustainable solutions for mitigating the environmental impacts of mining.