Calibrating passive sampling and passive dosing techniques to lipid based concentrations

Philipp Mayer, Stine Nørgaard Schmidt, A. Annika, MS Mclachlan, K. Maenpaa, MT Lappanen

Research output: Contribution to conferencePaperResearch


Equilibrium sampling into various formats of the silicone polydimethylsiloxane (PDMS) is
increasingly used to measure the exposure of hydrophobic organic chemicals in environmental
matrices, and passive dosing from silicone is increasingly used to control and maintain their
exposure in laboratory experiments. Both these equilibrium partitioning approaches are normally
calibrated to freely dissolved aqueous concentrations (Cfree), which often are considered the effective
concentration for partitioning, bioconcentration and toxicity. In the present studies we
extend the calibration of such methods towards equilibrium partitioning concentrations in lipids
(Clipid,partitioning). The first approach proceeds in two steps; (i) the concentration in the PDMS (CPDMS
) is determined and (ii) multiplied with recently determined lipid to PDMS partition ratios
(Klipid,PDMS). The second approach applies external partitioning standards in vegetable or fish oil
for the complete calibration of equilibrium sampling techniques without additional steps.
Equilibrium in tissue sampling in three different fish yielded lipid based PCB concentrations
in good agreement with those determined using total extraction and lipid normalization. These
results support the validity of the in tissue sampling technique, while at the same time confirming
that the fugacity capacity of these lipid-rich fish tissues for PCBs was dominated by the lipid
Equilibrium sampling of PCB contaminated lake sediments with PDMS coated vials and
with Head Space Solid Phase Microextraction (HS-SPME) yielded lipid based concentrations
that were in good agreement with each other, but about a factor of two higher than measured
lipid-normalized concentrations in the organisms.
Passive dosing was applied to bioconcentration and toxicity studies of several PAHs with the terrestrial
springtail Folsomia candida. Within the bioconcentration study, equilibrium partitioning
concentrations in lipids served as a well defined reference for the evaluation of measured concentrations
in the springtails. In the toxicity tests of naphthalene, phenanthrene and pyrene, lethal
concentrations were determined also on a Clipid,partitioning basis and were in good agreement with the
typical range of lipid membrane burdens for baseline toxicity (40-160 mM). This demonstrates
that these new calibration principles also can be applied within a toxicological context.

Original languageEnglish
Publication date15 May 2011
Number of pages3
Publication statusPublished - 15 May 2011
Externally publishedYes

Cite this