title: PAH fluxes to Siskiwit revisted: trends in fluxes and sources of pyrogenic PAH and perylene constrained via radiocarbon analysis.
abstract: Trends in concentrations and radiocarbon content of pyrogenic PAHs and perylene were determined 20 years after a previous study by Mcveety and Hites (1988). Pyrogenic PAH fluxes to sediments were observed to continue to decrease over the period from 1980 to 2000 at this remote site in contrast to observations in more urban areas. Radiocarbon analysis of pyrogenic PAHs showed a 50% decrease in the proportion of pyrogenic PAH derived from fossil fuel combustion over the past 50 years, consistent with decreasing emissions from regional coal-fired power-generating plants. Fluxes of pyrogenic PAHs related to biomass burning were consistent over this same period and found to exceed fossil fuel sources in the most recent samples. Fluxes of biomass-derived pyrogenic PAHs were similar in magnitude to total pyrogenic PAH fluxes in early 1900, suggesting that these fluxes may represent wildfire inputs. Not only did perylene concentrations in these sediments increase with depth as previously observed but also concentrations from the same sedimentary layers analyzed 20 years previously showed large increases in perylene concentrations. Radiocarbon analysis of perylene indicated that 70-85% of perylene observed in the deeper sediments could be explained by production from total organic carbon.
authors.affiliation: School of Geography and Earth Sciences, McMaster Unviersity, General Sciences Building room 306, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada. gslater@mcmaster.ca
authors.forename: G F
authors.initials: GF
authors.lastname: Slater
authors.forename: A A
authors.initials: AA
authors.lastname: Benson
authors.forename: C
authors.initials: C
authors.lastname: Marvin
authors.forename: D
authors.initials: D
authors.lastname: Muir
mesh_terms: D002250:Carbon Radioisotopes / Q000032:analysis*; D019015:Geologic Sediments / Q000737:chemistry*; D008824:Michigan; D010569:Perylene / Q000032:analysis / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D011786:Quality Control
chemical_list: D002250:Carbon Radioisotopes; D011084:Polycyclic Aromatic Hydrocarbons; D010569:Perylene