Development of an immunoassay for the determination of polyaromatic hydrocarbons in plasma samples from oiled seabirds.

External exposure assessment of oiled seabirds is undertaken by assessment of the percentage oil coverage of the plumage. Nondestructive monitoring of the toxic fraction of petroleum oils and diesels (polyaromatic hydrocarbons, PAHs) which enters the general circulation (internal exposure burden) of oiled seabirds is rarely undertaken. This is because the traditionally used chromatographic methods for plasma PAH analysis require larger sample volumes than those that can be safely collected from smaller species, such as guillemots (Uria aalge). Furthermore, these methods are not a cost-effective or practical approach for analysis of large numbers of birds in a short time period as part of an oil spill response in wildlife rehabilitation centers. This study describes the modification and validation of a commercially available PAH immunoassay (cRaPID PAH) to enable high-throughput, cost-effective, simple, and rapid determination of total PAH concentrations in 50 microL volumes of plasma. The limit of detection of the assay was 0.1 ng/mL as benzo-apyrene (BaP) equivalents with a working range of 0.120 ng/mL. As further validation of the immunoassay, PAHs were determined by GC-MS. GC-MS data were significantly positively correlated with corresponding immunoassay data for the same birds (r2 = 0.976, p < 0.001). The plasma PAH concentrations of 40 oiled guillemots stranded on U.K. shores were determined using the assay to demonstrate its usefulness for biomonitoring studies. The mean ,PAH concentration observed was 1.05 +/- 0.67 ppm (range 0.02-2.40 ppm as BaP equivalents). The modifications to the cRaPID PAH kit in this study enable nondestructive, high-throughput, semiquantitative determination of PAH concentrations in plasma samples suitable for exposure assessment of oiled seabirds during oil spill response and rehabilitation.