Bioavailability- and bioaccessibility-dependent mutagenicity of pentachlorophenol (PCP)
Csilla Hajdu, Katalin Gruiz and Éva Fenyvesi

The biological effect of a soil pollutant depends on its actual bioavailability and bioaccessibility, which is associated with the Kp value (soil-solid–soil-water partition coefficient) in the soil, and with the interaction between the soil and the test organism. Our aim is to find a biologically relevant conservative model for assessing the biologically effective proportion of the contaminant by increasing the bioavailability and/or bioaccessibility of the contaminant to a value that can be considered as the maximum in a biological system in the environment, for example, in freshwater or soil ecosystems.

We selected cyclodextrin, a starch-type molecule, in order to develop a reproducible interactive bioassay based on a pessimistic approach, but still remaining within a biologically realistic range. Cyclodextrin (CD) can be applied in nanotechnology, which allows us to modify the matrix-effect of the soil by simulating the maximum bioavailability/bioaccessibility of organic contaminants through their inclusion using cyclodextrin.

We introduce the mutagenicity testing of pentachlorophenol (PCP), a common, high-Kow (octanol–water partition coefficient) contaminant in soil with and without cyclodextrin pre-treatment. As an alternative to the cyclodextrin model, traditional bioavailability/bioaccessibility enhancement by simulating the process of human digestion was also tested and compared on contaminated soils. PCP has a high Kow and its mutagenicity is questionable, due to controversial data from the literature.

After complexation using RAMEB (randomly methylated b-cyclodextrin), a significant mutagenic effect was measured in PCP-contaminated soil. The same soil was negative even after simulated human digestion.

Key words: Ames test, bioaccessibility, bioavailability, cyclodextrin, ecotoxicology, mutagenicity, nanotechnology, pentachlorophenol, RAMEB, soil, whole-soil test 

Land Contamination & Reclamation, 17 (3-4), 473-481 (2009)

DOI 10.2462/09670513.973

© EPP Publications Ltd 2009

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Article code 973