Commercially available chemicals that mimic a deposit feeder's (Arenicola marina) digestive solubilization of lipids.

Abstract

To develop a simple and cost-effective bioavailability test for sediment-bound contaminants, the solubilization strengths of mixtures of four commercially available surfactants and four proteins were compared to that of digestive fluids from a deposit-feeding benthic polychaete Arenicola marina. Initial tests indicated that sodium taurocholate, a vertebrate bile salt, was the most accurate mimic of A. marina gut fluids' solubilization of individual polycyclic aromatic hydrocarbons (PAH). Further testing with nutritional lipids and other hydrophobic contaminants confirmed the similarities of these fluids. Bovine serum albumin (BSA) solubilization of PAH was the most efficient of all the proteins tested. A cocktail of sodium taurocholate and BSA was compared to A. marina's solubilization of 12 PAH from four different contaminated sediments (from Boston, Charleston, Jacksonville, and San Diego harbors). The two solutions released most PAH to similar extents; 40 of 48 PAH-sediment combinations were released at amounts within a factor of 2 in cocktail and gut fluid solutions. Therefore, the cocktail may serve as a surrogate for real gut fluids and allow easier adoption of the in vitro incubation approach to bioavailability testing.