The relationship between lipid class composition and the bioaccumulation of polychlorinated biphenyls in marine mussels

Barbara Jane Bergen, University of Rhode Island

Abstract

The concentration of hydrophobic contaminants in organisms is often expressed on a per-gram total-lipid weight basis; however, recent evidence suggests that the total lipid pool, which consists of lipid classes with widely varying structure and polarity, cannot be considered a uniform compartment when measuring or predicting bioaccumulation. The objectives of this work were: (1) develop a method and quality assurance guidelines for the analysis of marine lipid classes, (2) use the method to investigate the seasonal variability in polychlorinated biphenyls (PCBs) and lipids in a contaminated and reference population of ribbed mussels (Gukensia demissus), and (3) examine the variability in lipid class composition and PCBs in individual ribbed mussels along a pollution gradient. ^ The method developed demonstrated that lipid classes can be analyzed quantitatively with Iatroscan® TLC-FID. Samples need to be analyzed immediately after homogenization due to the rapid degradation of total lipid and lipid classes. A laboratory intercalibration verified the accuracy of the method and identification of the lipid classes. During the seasonal study, no significant relationship was observed between the PCB concentrations and total lipid; however, there was a significant relationship between total PCB and total triacylglycerol concentration at the contaminated site. The most significant difference between sites was that significantly higher total lipid, total nonpolar and triacylglycerol concentrations were observed in the contaminated population. To normalize PCBs or study their affects in animals with low lipid concentrations, it is desirable to measure lipid classes. At a minimum, total lipid should be separated into nonpolar and polar fractions. ^ Along a pollution gradient, variability in the measured parameters was greatest at the site with median PCB concentrations. The sample number needed to examine any population varied and should be assessed prior to beginning any field study. Studies with deployed and indigenous ribbed mussels showed that the acetone mobile polar lipid (AMPL) increases significantly when animals are deployed and may be an indicator of stress. Blue (Mytilus edulis ) and ribbed mussels have similar lipid classes; however, blue mussels accumulate more PCBs at lower water-temperatures demonstrating that PCB bioaccumulation is dependent on other factors than lipid concentration. ^

Subject Area

Biology, Molecular|Chemistry, Biochemistry|Environmental Sciences

Recommended Citation

Barbara Jane Bergen, "The relationship between lipid class composition and the bioaccumulation of polychlorinated biphenyls in marine mussels" (1999). Dissertations and Master's Theses (Campus Access). Paper AAI9945192.
http://digitalcommons.uri.edu/dissertations/AAI9945192

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