Sourcing of fossil fuel-derived PAH in the environment

To investigate the effects of domestic coal burning on the distribution and isotopic composition of environmental PAH, a series of soil samples were collected in a coal-burning village nearby Glasgow, UK. Analyses showed that, typically, PAHs in the Lochwinnoch village samples were isotopically heavy having delta C-13 values close to -25 parts per thousand that are consistent with the PAHs emanating from coal burning. It was also noted, however, that alkylated PAHs would appear to be more prominent in soot from coal fires than in the samples collected in Lochwinnoch where domestic combustion was determined to be the major source. Therefore, to address the possibility that parent PAHs may survive in soils preferentially, two weathering experiments have commenced using a low temperature coal carbonisation tar from the Coalite process. Initial results have shown that after as little as 80 days weathering period, parent PAHs, particularly fluoranthene and pyrene, become more prominent than alkylated species, suggesting that these compounds may survive oxidation/weathering to a greater extent than their alkylated counterparts.