Long-Term Field Study of Microbial Community and Dechlorinating Activity Following Carboxymethyl Cellulose-Stabilized Nanoscale Zero-Valent Iron Injection.
Nanoscale zerovalent iron (nZVI) is an emerging technology for the remediation of contaminated sites. However, there are concerns related to the impact of nZVI on in situ microbial communities. In this study, the microbial community composition at a contaminated site was monitored over two years following the injection of nZVI stabilized with carboxymethyl cellulose (nZVI-CMC). Enhanced dechlorination of chlorinated ethenes to nontoxic ethene was observed long after the expected nZVI oxidation. The abundance of Dehalococcoides (Dhc) and vinyl chloride reductase (vcrA) genes, monitored using qPCR, increased by over an order of magnitude in nZVI-CMC-impacted wells. The entire microbial community was tracked using 16S rRNA gene amplicon pyrosequencing. Following nZVI-CMC injection, a clear shift in microbial community was observed, with most notable increases in the dechlorinating genera Dehalococcoides and Dehalogenimonas. This study suggests that coupled abiotic degradation (i.e., from reaction with nZVI) and biotic degradation fueled by CMC led to the long-term degradation of chlorinated ethenes at this field site. Furthermore, nZVI-CMC addition stimulated dehalogenator growth (e.g., Dehalococcoides) and biotic degradation of chlorinated ethenes.
Civil & Environmental Engineering, Western University , 1151 Richmond Street, London, Ontario, Canada , N6A 5B8.|CH2M HILL Canada Limited , 72 Victoria Street Kitchener, Ontario, Canada , N2G 4Y9.
Chris M D
CM
Kocur
Chemical Engineering & Applied Chemistry, University of Toronto , 200 College Street, Toronto, Ontario, Canada , M5S 3E5.
Line
L
Lomheim
Chemical Engineering & Applied Chemistry, University of Toronto , 200 College Street, Toronto, Ontario, Canada , M5S 3E5.
Olivia
O
Molenda
Environmental Sciences Group, Chemistry and Chemical Engineering, Royal Military College of Canada , PO Box 17000, Station Forces, Kingston, Ontario, Canada , K7K 7B4.
Kela P
KP
Weber
CH2M HILL Canada Limited , 72 Victoria Street Kitchener, Ontario, Canada , N2G 4Y9.
Leanne M
LM
Austrins
Civil Engineering, University of Toronto , 35 Saint George Street, Toronto, Ontario, Canada , M5S 1A4.
Brent E
BE
Sleep
Civil & Environmental Engineering, Western University , 1151 Richmond Street, London, Ontario, Canada , N6A 5B8.
Hardiljeet K
HK
Boparai
Chemical Engineering & Applied Chemistry, University of Toronto , 200 College Street, Toronto, Ontario, Canada , M5S 3E5.
Elizabeth A
EA
Edwards
Civil & Environmental Engineering, Western University , 1151 Richmond Street, London, Ontario, Canada , N6A 5B8.
Denis M
DM
O'Carroll
D002266:Carboxymethylcellulose Sodium; D041862:Chloroflexi; D054879:Halogenation; D007501:Iron; D012336:RNA, Ribosomal, 16S
D012336:RNA, Ribosomal, 16S; D007501:Iron; D002266:Carboxymethylcellulose Sodium