Influence of soil type and organic matter content on the bioavailability, accumulation, and toxicity of alpha-cypermethrin in the springtail Folsomia candida.
The influence of organic matter (OM) content on alpha-cypermethrin porewater concentrations and springtail Folsomia candida accumulation was investigated in two soils with different levels of organic matter, a forest soil with a total organic carbon (TOC) content of 5.0% (OM=11.5%) and an agricultural soil with a TOC content of 1.3% (OM=4.0%). Also, the effects of alpha-cypermethrin concentrations in soil and pore water and the influence of soil aging on springtail reproduction were investigated. Springtail reproduction was severely affected by increasing alpha-cypermethrin in soil with 1.3% TOC; the median effective concentration value (EC50) was estimated to 23.4 mg/kg (dry wt). Reproduction was only marginally affected in the soil with 5.0% TOC, and no EC50 value could be estimated. However, when expressing alpha-cypermethrin accumulation as a function of soil alpha-cypermethrin concentrations, no difference was found between the two soil types, and no additional alpha-cypermethrin uptake was observed at soil concentrations above approximately 200 mg/kg (dry wt). By using solid-phase microextraction (SPME), it could be demonstrated that alpha-cypermethrin porewater concentrations were higher in the soil with low organic matter (LOM) content than in the soil with high organic matter (HOM) content. Furthermore, a clear relationship was found between alpha-cypermethrin concentrations in springtails and porewater. Soil aging was not found to exert any effect on alpha-cypermethrin toxicity toward springtails. The study indicates that the springtail's accumulation of alpha-cypermethrin and reproduction is governed by alpha-cypermethrin porewater concentrations rather than the total alpha-cypermethrin concentration in soil.
Styrishave
Bjarne
B
Department of Terrestrial Ecology, National Environmental Research Institute, University of Aarhus, Vejlsøvej 25, P.O. Box 314, DK-8600 Silkeborg, Denmark.
Hartnik
Thomas
T
Christensen
Peter
P
Andersen
Ole
O
Jensen
John
J
D000818:Animals; D001181:Arthropods / Q000187:drug effects*; D001682:Biological Availability; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000493:pharmacokinetics / Q000633:toxicity; D011722:Pyrethrins / Q000493:pharmacokinetics* / Q000633:toxicity*; D012987:Soil / Q000032:analysis*
D007306:Insecticides; D011722:Pyrethrins; D012987:Soil; C017160:cypermethrin