Application of cyclodextrins in environmental bioassays for soil

作者：Hajdu Csilla^*; Gruiz Katalin; Fenyvesi Eva; Nagy Zsuzsanna Magdolna

来源：Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2011, 70(3-4): 307-313.

DOI：10.1007/s10847-010-9855-8

• Cyclodextrins in bioassays
• Environmental bioassay
• Toxicity
• Mutagenicity
• Bioavailability of contaminants
• Mobility of contaminants
• Risk assessment
• Contaminated soil
• Randomly methylated beta-cyclodextrin
• Pentachlorophenol

Based on our former experience on contaminant solubilisation and mobilisation in the process of soil remediation we used cyclodextrins as additives in environmental bioassays, for improving solubility and bioavailability of the contaminant in soil and as a consequence sensitivity of the bioassay. In this article we introduce the findings on the application of RAMEB (randomly methylated beta-cyclodextrin) for testing PCP (pentachlorophenol) in soil, in three bioassays: bacterial luminescence-inhibition test with Vibrio fischeri, protozoon growth inhibition test with Tetrahymena pyriformis, and Ames mutagenicity test. We applied RAMEB which has a high solubilising capacity on many typical soil contaminant and PCP, because contradictory results were published for its toxicity and mutagenicity. The RAMEB-aided Ames test, gave a sudden and expressed increase in the mutagenicity of PCP, however, Ames mutagenicity was negative without cyclodextrin (CD). Based on these results we tried to apply RAMEB for increasing sensitivity of other bioassays, such as acute toxicity tests with different test organisms. According to our results the effect of RAMEB on bioavailability and toxic effect depends not only on the K-ow value (octanol-water partition coefficient) of the chemical substances, but also on the test organism, the water-content of the test-matrix and the applied concentration of RAMEB, as well as its ratio to PCP. We collected all the characteristics of the bioassays applied for PCP and some other contaminants and showed the measured effect data in comparison with each other. We found that in the complex system of soil and soil suspension, used in the bioassays, the interactions between soil solid, water and gaseous phases, as well as between the test organism and RAMEB result in K-ow dependent partition of the contaminant between solid and water phases of soil, RAMEB, and the test organism. The conclusion is that RAMEB undoubtedly has an influence on the fate and behaviour of the contaminant in soil and soil suspensions, and the direction of the RAMEB-induced changes depends on the effective concentration of the RAMEB in the bioassay, the time of contact, the type of test organism, and the characteristics of the RAMEB-contaminant complex. In those cases, when RAMEB increased the effect of a contaminated environmental sample, this CD-induced increase can be considered as a "realistic worse case" situation, which can be very useful in risk assessment, resulting in a moderate overestimate in the value of environmental risk.

• 出版日期2011-8