| The objective of this study is to establish a simple and cost-effective method to enhancement of intrinsic polycyclic aromatic hydrocarbon (PAHs) bioremediation. Soil amendments such as peat, cedar and pine bark were supplemented to the soil which contained 11 of 16 US EPA priority PAHs. Results from the first-year study showed peat moss, among three soil amendments, exhibited the potential to enhance PAH biodegradation. 10% Peat moss added to soil exhibited 62.5% removal of total PAHs from the soil. Meanwhile the untreated control only showed 10.7% of PAH depletion. Further study focused on exploring the enhancement effects of peat moss addition for PAH biodegradation. Several factors were tested including temperature, different amount of peat moss and minimal salt medium addition. 10% Peat moss addition at 25°C and 30°C yielded PAH depletion percentages, 54.2% and 71.6%, respectively. Moreover at 25°C, minimal salt medium was able to enhance PAH removal to 75.8% in 10% peat moss added soil. The depletion of 5- and 6-ring PAHs also increased relatively higher in peat moss supplemented soil.; Changes in number of bacterial, determined by direct plate count, consistently correlated with PAH depletion. The total bacteria numbers in peat moss added soils increased approximately 10 fold compared with the untreated soils. The number of PAH-degrading bacteria numbers, determined by using naphthalene as the sole carbon source, exhibited the 17–30 fold of increase in peat moss added soils. Meanwhile the number of PAH-degrading bacteria in the untreated soil remained relatively stable.; This study is the first report in which peat moss was used to enhance PAH biodegradation, and the results suggested considerable potential for field-scale bioremediation. |
