title: Nonexhaustive beta-cyclodextrin extraction as a chemical tool to estimate bioavailability of hydrophobic pesticides for earthworms.
abstract: Chemical methods to assess bioavailability in soil and sediment often use synthetic polymers that mimic uptake of organic compounds in organisms or microbial degradation. In this paper we have assessed a biomimetic extraction method using hydroxyl-beta-cyclodextrin (HP-beta-CD) to estimate uptake of the two insecticides alpha-cypermethrin (alpha-CYP) and chlorfenvinphos (CFVP) in the earthworm Eisenia fetida. Additionally, a novel approach was developed to estimate the efficiency of biomimetic extractions. The study revealed that HP-beta-CD is a suitable surrogate for estimating the bioaccessibility of hydrophobic chemicals in soil. If one uses a 3.5 times higher amount of HP-beta-CD than soil, effective and reproducible extractions can be achieved within 48 h. Atthese conditions, inclusion of dissolved chemicals by HP-beta-CD mimics uptake of a given compound into earthworms and takes into account sorption-related aspects that control biological uptake. The data indicate that, with increasing hydrophobicity, the affinity of organic chemicals to HP-beta-CD does not increase to the same degree as to soil organic matter. Therefore, a high surplus of HP-beta-CD is necessaryto provide a sufficient extraction capacity in biomimetic extractions.
authors.affiliation: Bioforsk-Norwegian Institute for Agricultural and Environmental Research, Frederik A. Dahls Vei 20, 1432 As, Norway. thomas.hartnik@bioforsk.no
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartnik
authors.forename: John
authors.initials: J
authors.lastname: Jensen
authors.forename: Joop L M
authors.initials: JL
authors.lastname: Hermens
mesh_terms: D000327:Adsorption; D000818:Animals; D001682:Biological Availability; D002709:Chlorfenvinphos / Q000737:chemistry / Q000493:pharmacokinetics*; D057927:Hydrophobic and Hydrophilic Interactions; D007306:Insecticides / Q000737:chemistry / Q000493:pharmacokinetics*; D009835:Oligochaeta / Q000378:metabolism*; D011722:Pyrethrins / Q000737:chemistry / Q000493:pharmacokinetics*; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry / Q000493:pharmacokinetics; D047392:beta-Cyclodextrins / Q000737:chemistry / Q000493:pharmacokinetics*
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D012987:Soil; D012989:Soil Pollutants; D047392:beta-Cyclodextrins; C017160:cypermethrin; D002709:Chlorfenvinphos; C031215:betadex