Hydroxypropyl-β-cyclodextrin-based extraction for diuron bioaccessibility in an artificially contaminated soil

Abstract

Different extraction techniques are presented here to determine whether their extraction abilities correlate with the bioaccessible diuron fraction in an aged contaminated soil. Diuron bioaccessibility was tested establishing correlations between the amount of diuron biodegraded after different aging periods, using a specific diuron biodegrader microorganism consortium, and the amount of diuron extracted by 50 mM hydroxypropyl-β-cyclodextrin (HPBCD), 10 mM CaCl₂, hexane, or butanol. HPBCD extraction procedure correlated better than the other extraction techniques tested with diuron measured microbial biodegradation for all aging times (1, 30, 60, 90, and 120 days). The results obtained with this soil indicate that the aqueous HPBCD extraction technique has potential to become a valuable tool for estimating the bioaccessible fraction of soil-associated diuron at different aging times, and it could be applicable in the assessment of risk and contaminated land bioremediation potential.

Keywords:

• bioaccessibility
• bioavailability
• diuron
• hydroxypropyl-β-cyclodextrin
• risk assessment
• soil contamination

Acknowledgments

Marina Rubio thanks the Spanish Research Council (CSIC) for her Predoctoral Research grant (JAE-Pre). The authors are indebted to Presmar S.L. for providing the technical diuron. This work was supported by the Spanish Ministry of Science and Innovation (co-funded by the Fondo Europeo de Desarrollo Regional, FEDER), under the research projects CTM2006-04626 and CTM2009-07335.

This work was first presented at the 7th European Conference on Pesticides and Related Organic Micropollutants in the Environment and 13th Symposium on Chemistry and Fate of Modern Pesticides, 7–10 October 2012, Porto, Portugal.