Molecular and Isotopic Records of Combustion Inputs to the Environment Over the Last 250 Years
Abstract
The most ubiquitous source of polycyclic aromatic hydrocarbons (PARs) to the environment is incomplete combustion. This study generated a high-resolution historical record of pyrogenic PAR emissions since pre-industrial times from anoxic aquatic sediments, allowing for detailed comparison with energy consumption data. We show that an increase in PAR concentrations over the last decade may be due to a rise in emissions from diesel-powered vehicles. Compound-specific radiocarbon measurements demonstrated unequivocally that the proportion of PARs derived from fossil fuel combustion has increased substantially during the 20th century. delta(exp13)C and Delta(exp14)C measurements were also used to constrain the relative importance of combustion versus in situ production as sources of perylene. In addition, a comparison of the down-core concentration and isotopic profiles of black carbon (BC) generated by a combination of chemical and/or thermal oxidation methods highlighted the limitations of these methods when applied to sedimentary matrices. Finally, parallel lead and cesium isotopic records revealed two new potential stratigraphic markers in North American sedimentary records. 206Pb/207Pb profiles show a distinct peak in the mid-19th century, while a 137Cs peak was found to coincide with the 1986 Chernobyl accident.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2004
- Accession Number
- ADA426947
Entities
People
- Ana L. Delima
Organizations
- Woods Hole Oceanographic Institution