Follow up to feasibility study on in vitro biotransformation systems: Determination of uptake, loss and bioconcentration of two surfactants

EXECUTIVE SUMMARY

This ERASM-sponsored study was a follow-up study to the ERASM-sponsored feasibility study “Identification of an In Vitro Method for Estimating the Bioconcentration of Surfactants in Fish”, by S. Dyer, M.J. Bernhard, and D. Versteeg, in which the biotransformation of C12-2LAS (2-phenyl dodecane p-sulfonate) and C13EO8 (Octaethylene glycol monotridecyl ether) was determined.
In this study, two in vitro cellular systems were tested to determine the biotransformation of two surfactants, octaethylene glycol monohexadecyl ether (C16EO8) and diethylene glycol monotetradecyl ether sulfate (C14E2S). The two systems consisted of primary hepatocytes from Cyprinus carpio and an immortalized hepatic cell line from the desert topminnow, Poeciliopsis lucida (PLHC-1). The cell systems were exposed to surfactants for approximately 72h in 96-well microtiter plates. Uptake rates of surfactants into cells and loss rates due to biotransformation were determined using radiochemical methods. Bioconcentration (BCFcell) in cells of surfactants were also determined and compared to modeled and measured BCFs in fish. The BCFcell values for C16EO8 were 25 and 184 for primary hepatocytes and PLHC-1 cells, respectively.

The modeled (BCFWIN) and measured BCFfish (Tolls, 1998) values for the same surfactant were 62 and 387, respectively. The BCFcell values for C14E2S were 15 and 12 for primary hepatocytes and PLHC-1 cells, respectively, which were at least a factor of 4 lower than the modeled BCF of 71 (BCFWIN).
While this study and the previous ERASM-sponsored work supports the future development and use of cellular assays to estimate BCFs, additional effort will require the use of cold analytical methods and automation to make these assays more efficient and cost-effective.