INTERFERENCE OF AVIAN GUANO IN ANALYSES OF FUEL-CONTAMINATED SOILS

Site characterization on Johnston Island, Johnston Atoll, Pacific Ocea n, has yielded preliminary data that seabird guano can be an interfere nce in three common petroleum hydrocarbon quantification methods. Vola tiles from seabird guano were measured on a hydrocarbon-specific handh eld vapor meter (catalytic detector) in concentrations as high as 256 ppm by volume total hydrocarbon. Analysis of guano solids produced mea surable concentrations of total petroleum hydrocarbon (TPH) as diesel using both an immunoassay test and the EPA 8015 Modified Method. The t esting was conducted on one surface sample of guano collected from a s eabird roosting and nesting area. Source species were not identified. Positive hydrocarbon test results for guano raise concerns regarding t he effectiveness of standard methods of petroleum-contaminated site ch aracterization for Johnston Island, other Pacific islands, and coastal areas with historic or contemporary seabird populations.