Title:
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Biodegradation of polycyclic aromatic hydrocarbons in "pristine " soils from different environmental systems
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Global soils have the capacity to act as a sink for polycyclic aromatic hydrocarbons
(PAHs) and subsequently as a secondary source making soil/PAH interactions
important to environmental PAH levels. A number of physical, chemical and
biological processes determine P AH fate in soil but microbial degradation is the most
important. Biodegradation depends on bioavailability, soil organic matter, water and
nutrient content, temperature and previous exposure to PAHs. Globally, environments
differ and soils from different geographic regions differ in their properties and PAH
concentrations. While the importance of diffuse P AH contamination of soils is widely
acknowledged in literature, most studies on P AH biodegradation in soils have been
conducted on soils contaminated from a P AH point source. The aims of this project
were to investigate the indigenous biodegradation of PAHs in pristine soils from
different geographic locations as well as what environmental factors are most
significant in the development of PAH biodegradation potential in pristine soils.
Pristine soils used include soils from Antarctica, Norway, UK and Tibet. Levels of
PAHs in all the soils were low and properties like soil organic matter, nutrients and
water content were different. P AH degrading bacteria were present in all the soils
studied irrespective of low PAH concentrations. Temperature was found to affect both
the rates and extents of P AH degradation in the Antarctic soils. Results also suggest
that the effect of temperature on adaptation of indigenous microbes to PAH
degradation might be more important than that of lack of exposure. Further works
suggested include the identification of individual P AH -degrading bacteria in these
background soils and investigating the effect of increasing soil P AH-contact time in
low organic matter background Antarctic soils.
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