PCB Dissipation and Microbial Community Analysis in Rhizosphere Soil Under Substrate Amendment Conditions

Abstract

ABSTRACT Dissipations of PCB in soils under factorial combinations of soil amendment (biphenyl, pine needles, orange peels, unamended) and planting (reed canarygrass, flat pea, burr medic, unplanted) regimes were evaluated in relation to carbon substrate utilization patterns of corresponding soil microbial populations. We examined potential differences among microbial communities under the treatments and then related the differences to PCB dissipation. Based on univariate analysis of treatment results, three PCB dissipation groups were identified. They were (1) high: 50% or more loss of an original 50 mg/kg aroclor 1248 after 100 d, (2) medium: 40 to 50% loss, and (3) low: <20% loss. A canonical discriminant analysis (CDA) was performed on the data with the PCB dissipation grouping as the class variables and the carbon substrates as exploratory variables so as to relate PCB dissipation to C substrate use. The three PCB dissipation groups were reconstructed based on a subset of C substrates. The CDA identified C substrates that were most important in differentiating between population communities under the various treatments. The potential importance of the ability to correlate community substrate utilization to contaminant dissipation is discussed.