Abstract:

In this project, a group of mahi-mahi (Coryphaena hippurus) fish were exposed to high energy water accommodated fraction (HEWAF) of oil for 24 hours. Blood was then extracted from fish, and plasma was isolated. The plasma was analyzed for the polycyclic aromatic hydrocarbon (PAH) content. Phenanthrene C14 was added to the blood extracted from a different group of mahi-mahi fish that had not been previously exposed to PAH. The blood was then analyzed to determine the distribution of Phenanthrene in the blood (plasma, red blood cells or plasma bound). The measurement of both total PAH and phenanthrene in plasma was done using Gas chromatography/mass spectrometry - selective ion monitoring (GC/MS-SIM) technique. The quantification of phenanthrene C14 partitioning in the blood of mahi-mahi was used to estimate the concentration of physiologically active PAHs following exposure to environmentally relevant concentrations of oil following the Deepwater Horizon (DWH) oil spill.

Suggested Citation:

Cox, G.; Schauer, K.; Grosell, M.. 2019. Laboratory measurements of polycyclic aromatic hydrocarbon (PAH) concentrations in the blood of mahi-mahi (Coryphaena hippurus). Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-ae8q-ne83

Purpose:

To determine the distribution of phenanthrene as a representative polycyclic aromatic hydrocarbon (PAH) between blood plasma and blood cells.

Data Parameters and Units:

The excel files "Blood Samples" and "Whole Fish Biological Data" contains data collected for blood samples treated with phenanthrene C14, and data collected for whole fish treated with oil respectively. Oil treatment was 10% HEWAF. It includes - Fish ID; Sample ID; Treatment; Gender (female/male); Weight (kg); HCT (haematocrit); HCT % (percent haematocrit). The file Raw measurements.csv includes: Sample ID = The format for these is (Fish #)(Replicate) (Sample Type); sample type = P: Raw plasma, PL: Plasma liquid (liquid remaining after protein precipitation), PP: Plasma protein (precipitated proteins from plasma); Counts (radiation count); Sample wt (g) = Actual measured weights for the plasma in scintillation vials; aliquot wt (g) =mass of plasma taken for protein precipitation; measured liquid wt (g) = mass of plasma liquid sample including acid (minus protein precipitate) - taken after protein was spun down. Note: N/A means not applicable because some of these values are not applicable depending on the sample type. For instance, an aliquot was only taken for the PL and PP samples.

Methods:

The oil used to prepare all HEWAFs collected during the DWH oil spill. Each HEWAF was prepared within 24 hrs to use at a loading rate of 2 g of oil per litre of 1 micron filtered, UV- sterilized seawater and mixed in a Waring CB15 blender (Torrington, CT) at low speed for 30 s. The mixture was immediately transferred to a glass separatory funnel, allowed to settle for 1 h, and the lower ∼90% carefully drained and retained for subsequent use as 100% WAF (unfiltered) that was diluted for test exposures. Two groups of mahi-mahi were used in this study. The first group was exposed to 10% HEWAF for 24 hours and then blood was taken via cardiac puncture, spun down to separate plasma from red blood cells, and the plasma was sent to ALS for analysis of PAH content. Blood was taken from the second group of fish of non-oil exposed fish and treated with Phenanthrene C14. The blood was then analysed to determine the distribution of Phenanthrene in the blood (plasma, red blood cells or plasma bound). PAH content and Phenanthrene C14 were analyzed as prescribed by the EPA Method 827D.

Instruments:

Gas chromatography/mass spectrometry - selective ion monitoring (GC/MS-SIM) was used to measure PAH content and Phenanthrene C14 while Beckman LS6500 was used to measure radiation.

Individual Files: