Degradation mechanisms of DDX induced by the addition of toluene and glycerol as cosubstrates in a zero-valent iron pretreated soil.
Abiotic and biotic processes can be used to remediate DDX (DDT, DDD, DDE, and DDNS) contaminated soils; these processes can be fostered using specific carbon-amendments to stimulate particular soil indigenous microbial communities to improve rates or extent of degradation. In this study, toluene and glycerol were evaluated as cosubstrates under aerobic and anoxic conditions to determine the degradation efficiencies of DDX and to elucidate possible degradation mechanisms. Slurry microcosms experiments were performed during 60 days using pretreated soil with zero-valent iron (ZVI). Toluene addition enhanced the percentage of degradation of DDX. DDNS was the main compound degraded (around 86%) under aerobic conditions, suggesting cometabolic degradation of DDX by toluene-degrading soil bacteria. Glycerol addition under anoxic conditions favored the abiotic degradation of DDX mediated by sulfate-reducing bacteria activity, where DDT was the main compound degraded (around 90%). The 16S rDNA metagenomic analyses revealed Rhodococcus ruber and Desulfosporosinus auripigmenti as the predominant bacterial species after 40 days of treatment with toluene and glycerol additions, respectively. This study provides evidence of biotic and abiotic DDX degradation by the addition of toluene and glycerol as cosubstrates in ZVI pretreated DDX-contaminated soil.
Posgrado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico City, Mexico.
Antonio
A
Velasco
Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria, 3083, Australia; Departamento de Biotecnología, Escuela de Ingeniería, Instituto Tecnológico y de Estudios Superiores de Monterrey (ITESM), Vía Atlixcáyotl No. 2301, Reserva Territorial Atlixcáyotl, San Andrés Cholula, 72800, Puebla, Mexico.
Arturo
A
Aburto-Medina
Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria, 3083, Australia.
Esmaeil
E
Shahsavari
Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico City, Mexico.
Sergio
S
Revah
Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico City, Mexico. Electronic address: irmene@correo.cua.uam.mx.
Irmene
I
Ortiz
D000332:Aerobiosis; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D003634:DDT / Q000031:analogs & derivatives*; D004269:DNA, Bacterial / Q000235:genetics; D005990:Glycerol / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D014050:Toluene / Q000737:chemistry*
D004269:DNA, Bacterial; D012989:Soil Pollutants; D014050:Toluene; D003634:DDT; D007501:Iron; D005990:Glycerol
Biostimulation; Cosubstrates; DDT; Soil remediation; Zero-valent iron