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.

Review: In situ and bioremediation of organic pollutants in aquatic sediments

“…Surfactants are used as potential agents for enhanced solubility and removal of contaminants from soil and sediments [39][40][41][42]. Both biosurfactants, like bile salt, sodium taurocholate, and synthetic surfactants, like Triton X-100 and sodium dodecyl sulphate, have proved to increase the bioavailability of contaminants like PAHs and PCBs [43][44][45].…”

Explaining differences between bioaccumulation measurements in laboratory and field data through use of a probabilistic modeling approach

“…Through the model parameterization, we allowed for sediment (i.e., sediment organic matter) digestion to occur, which resulted in a more important chemical uptake from sediment ingestion relative to porewater exchange. Indeed, gut fluid extraction and subsequent contaminant accumulation during sediment ingestion have been observed in many sediment‐dwelling organisms (Mayer et al 1996; Voparil et al 2004; Voparil and Mayer 2004). By adopting an EqP approach, between animal and porewater and the BC concept (regarding solid–water partitioning), we would greatly underpredict contaminant accumulation and discard biomagnification, especially for chemicals with log K OW > 5.…”

“…This process will also be influenced by sediment composition (e.g., BC content) (Janssen et al 2010). Increased desorption and/or uptake due to gut fluids can be estimated by extracting contaminated sediments with synthetic gut fluids shown to mimic polychaete gut fluids (Voparil and Mayer 2004). Increased uptake from sediment due to digestion of particles is strongly influenced by sorption of the contaminant to the particle type and digestibility of the particle itself (Gunnarsson et al 1999; McLeod et al 2004).…”

Alteration of organic matter during infaunal polychaete gut passage and links to sediment organic geochemistry. Part I: Amino acids

“…Lauerman et al, 1997). Moreover, the digestive tracts of benthic invertebrates contain bacteria, enzymes, acids and surfactants (Longbottom, 1970;Mayer et al, 1997;Ahrens et al, 2001a;Voparil and Mayer, 2004), and are thus adapted to break down complex polymers, releasing simple biochemicals for assimilation. The rate at which these gut fluids act is very rapid, with Ahrens et al (2001a) reporting the majority of contaminant desorption to occur in the first minute of contact with sediment.…”