Potential for Polychlorinated Biphenyl Biodegradation in Sediments from Indiana Harbor and Ship Canal.
Polychlorinated biphenyls (PCBs) are carcinogenic, persistent, and bioaccumulative contaminants that pose risks to human and environmental health. In this study, we evaluated the PCB biodegradation of sediments from Indiana Harbor and Ship Canal (IHSC), a PCB-contaminated site (average PCB concentration = 12,570 ng/g d.w.). PCB congener profiles and bacterial community structure in a core sediment sample (4.57 m long) were characterized. Analysis of vertical PCB congener profile patterns in sediment and pore water strongly suggest thatin situdechlorination occurred in sediments. However, 16S rRNA genes from putative PCB-dechlorinatingChloroflexiwere relatively more abundant in upper 2 m sediments, as were genes indicative of aerobic biodegradation potential (i.e. biphenyl dioxygenase (bphA)). Characterization of the bacterial community by terminal restriction fragment length polymorphism and comparison of these with sediment and pore water PCB congener profiles with the Mantel test revealed a statistical correlation (p<0.001). Sequences classified asAcinetobacterandAcidovoraxwere highly abundant in deep sediments. Overall, our results suggest that PCB dechlorination has already occurred, and that IHSC sediments have the potential for further aerobic and anaerobic PCB biodegradation.
Department of Civil and Environmental Engineering, 4105 Seamans Center, The University of Iowa, Iowa City, IA, 52242, USA.
Yi
Y
Liang
Department of Civil and Environmental Engineering, 4105 Seamans Center, The University of Iowa, Iowa City, IA, 52242, USA.
Andres
A
Martinez
Department of Civil and Environmental Engineering, 4105 Seamans Center, The University of Iowa, Iowa City, IA, 52242, USA.
Keri C
KC
Hornbuckle
Department of Civil and Environmental Engineering, 4105 Seamans Center, The University of Iowa, Iowa City, IA, 52242, USA.
Timothy E
TE
Mattes
Chloroflexi; Indiana Harbor and Ship Canal sediment; PCBs; bacterial communities; bphA