Heavy oils, which are more viscous and less effected by physical processes persist longer. Microbial degradation, the ultimate fate of most tar balls in the marine environment, is limited by the available surface area of the petroleum and by the recalcitrant petroleum constituents. The possible matches would then require conformation by a qualitative comparison of all chromatographic data. Mathematical, or statistical, techniques were limited by the lack of replication and range in index values. The use of statistical principal component analyses may provide a higher degree of separation of suspected sources.
More work is required to fully develop a statistical approach to source-fingerprinting.
Several of the sources appear to be derived from the discharge of tanker washings containing crude oil and high molecular weight paraffins. Biomarker signatures typical of Middle East and Alaskan North Slope crudes have been identified in the tar balls analyzed. Henry, C.B., P.O.Roberts and E.B. Overton. 1993. Characterization of Chronic Sources and Impacts of Tar along the Louisiana Coast. OCS study MMS 93-0046.