Radiocarbon as a tool to apportion the sources of polycyclic aromatic hydrocarbons and black carbon in environmental samples.
To determine the relative inputs of polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) in environmental samples from the combustion of fossil fuels and biomass, we have developed two independent analytical methods for determining the 14C abundance of PAHs and BC. The 5730 yr half-life of 14C makes it an ideal tracer for identifying combustion products derived from fossil fuels (14C-free) versus those stemming from modern biomass (contemporary 14C). The 14C abundance of PAHs in several environmental Standard Reference Materials was measured by accelerator mass spectrometry after extraction and then purification by high-performance liquid chromatography and preparative capillary gas chromatography. This method yields pure compounds that allow for a high degree of confidence in the 14C results. The PAHs data were then used to compare and evaluate results from an operationally defined thermal oxidation method used to isolate a BC fraction. The 14C compositions of PAHs and BC were very similar and suggest that the thermal oxidation method employed for isolating BC is robust and free from interferences by non-BC components. In addition, these data indicate that both the PAHs and the BC species derive mostly from fossil fuels and/or their combustion products.
Reddy
Christopher M
CM
Department of Marine Chemistry and Geochemistry and National Oceans Sciences Accelerator Mass Spectrometry Facility, Woods Hole, Massachusetts 02543, USA. creddy@whoi.edu
Pearson
Ann
A
Xu
Li
L
McNichol
Ann P
AP
Benner
Bruce A
BA
Wise
Stephen A
SA
Klouda
George A
GA
Currie
Lloyd A
LA
Eglinton
Timothy I
TI
D018533:Biomass; D002244:Carbon / Q000032:analysis*; D002250:Carbon Radioisotopes / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005579:Fossil Fuels; D017745:Incineration; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012680:Sensitivity and Specificity
D002250:Carbon Radioisotopes; D005579:Fossil Fuels; D011084:Polycyclic Aromatic Hydrocarbons; D002244:Carbon