Sorptive Capacity of Membrane Lipids, Storage Lipids, and Proteins: A Preliminary Study of Partitioning of Organochlorines in Lean Fish from A PCB-Contaminated Freshwater Lake

Abstract

Knowledge on the internal distribution of halogenated organic chemicals (HOCs) would improve our understanding of dose-effect relationships and subsequently improve risk assessment of contaminated sites. Herein, we determine the concentrations of HOCs based on equilibrium partitioning in storage lipids, membrane lipids, and proteins in field-contaminated fish using equilibrium sampling devices. The study shows the importance of protein as a sorptive phase in lean fish. Our results provide a basis for using species-specific equilibrium partitioning coefficients between sorptive tissues and fish internal water as a substitute for K(ow) in, for example, upgrading models that simulate food-chain accumulation of the chemical.

Fate of polychlorinated biphenyls in a contaminated lake ecosystem: Combining equilibrium passive sampling of sediment and water with total concentration measurements of biota

“…It is noteworthy that estimated equilibrium partitioning concentrations in lipid were ( C Lip ⇌Sed ) determined for a model neutral storage lipid, which is only an idealized equilibrium partitioning reference phase because biota lipids have a more complex composition. It gives a good approximation for lipid‐rich biota such as eel, but it may be less accurate for lean biota in which other sorption phases such as polar lipids or proteins may be important for hydrophobic organic chemicals . Currently, C Lip ⇌Sed reflects equilibrium partitioning concentrations in storage lipids, which show hardly any differences in their partitioning properties for hydrophobic organic chemicals .…”

“…Partitioning of bioaccumulative compounds between different sorbing phases of organisms has recently been investigated to better define tissue‐specific concentrations. These results showed that lipid normalization is a preferred transformation for the concentrations measured in biota because hydrophobic organic chemicals absorb predominantly in neutral lipids and less in polar lipids and proteins . Therefore, the approach undoubtedly results in conservative estimates in this respect because a portion of the total lipids consists of polar lipids.…”

“…This provides a lipid concentration estimate for a hypothetical lipid–sediment equilibrium. Estimated C Lip ⇌ Sed values were higher than actual measured lipid‐normalized concentrations ( C Lip,Bio ) of native sediment‐dwelling invertebrates , possibly because of metabolization of the chemicals and a higher sorptive capacity of storage lipids compared with membrane lipids . An organism may be in disequilibrium with its environment for several reasons, including slow uptake kinetics of hydrophobic organic chemicals, biomagnification, or biotransformation.…”

“…Moreover, low‐density PE , polyoxymethylene devices , ethylene vinyl acetate films , and silicone microtubes have been used for passive sampling. Furthermore, refinements such as thin polymer layers and in vivo sampling of biota have increased the applicability of passive samplers, and new methods have been developed especially for predicting equilibrium partitioning concentrations of hydrophobic organic chemicals in model lipids .…”

Coupling passive sampling with in vitro bioassays and chemical analysis to understand combined effects of bioaccumulative chemicals in blood of marine turtles

“…Recent advances in polymer-based passive sampling using polydimethylsiloxane (PDMS), for example, have opened an opportunity for rapid, quantitative extraction of neutral organic chemical mixtures from biological samples, based on equilibrium partitioning between the polymer and major sorption phases, such as lipid and proteins (Jahnke et al, 2008(Jahnke et al, , 2009(Jahnke et al, , 2011(Jahnke et al, , 2014Jahnke and Mayer, 2010;Allan et al, 2013;Mäenpää et al, 2014). Combined with high-throughput bioanalytical tools, this polymer-based extraction method facilitates our understanding of mixture effects of bioaccumulative chemicals present in lipid-rich tissues, such as dugong blubber (Jin et al, 2013(Jin et al, , 2015.…”