Extraction and Analysis of Asphalt Pavement Core Samples: Detection of Coal Tar-Derived Species using Chemical and Biological Methods

Epidemiological studies [1,2] have reported elevated cancer incidences and mortality in the Danish mastic asphalt industry, and have associated these elevations with exposure to asphalt fumes. The strength of the causal association depends heavily on the claim that coal tar was not used in the industry after World War II; otherwise, exposure to coal tar pitch volatiles would have seriously confounded study results. Yet, other reports [3,4,5] indicate coal tar was used well into the 1970's. To clarify the issue, the Copenhagen Road Institute collected core samples from sites where the history of mastic application was known. Coded samples were extracted, and subjected to HPLC separation, GC-MS, fluorescence fingerprinting and the Diazo test for phenolics. The extracts were also tested in the Modified Ames Assay. The results of the study show that the composition and mutagenicity of the core samples until 1970 were consistent with the presence of coal tar.