Sediment microbes and biofilms increase the bioavailability of chlorpyrifos in Chironomus riparius (Chironomidae, Diptera).
In a microcosm study, the importance of different sources of organic matter (humic acids, sterile sediment, sediment, and a microbial extract) for the bioavailability of the hydrophobic pesticide chlorpyrifos to Chironomus riparius larvae was quantified. In the last two treatments biofilms were allowed to grow before (14)C-chlorpyrifos addition. Chlorpyrifos accumulation was quantified after 25 h of exposure and after 21 h of depuration. Larval accumulation was twice as high in the microbial extract treatment (447+/-79 microg/kg ww larvae) and 1.7 times higher in the sediment treatment (371+/-33 microg/kg). After depuration, chlorpyrifos accumulation in larval tissue showed even higher differences; 3.1 times higher tissue concentrations in the microbial extract treatment (218+/-21 microg/kg) and 2.2 times higher in the sediment treatment (156+/-35 microg/kg). In contrast, chlorpyrifos accumulation in the humic acid and sterile sediment did not differ from that in controls. These results show that living microbes and biofilms, by creating a microenvironment and providing food for larvae, markedly increase the bioavailability of chlorpyrifos to Chironomus riparius.
Widenfalk
Anneli
A
Department of Environmental Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, SE-750 07 Uppsala, Sweden.
Lundqvist
Anna
A
Goedkoop
Willem
W
D000818:Animals; D018441:Biofilms; D001682:Biological Availability; D002244:Carbon / Q000032:analysis; D002683:Chironomidae / Q000378:metabolism*; D004390:Chlorpyrifos / Q000493:pharmacokinetics*; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology*; D006812:Humic Substances / Q000382:microbiology; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis
D006812:Humic Substances; D002244:Carbon; D004390:Chlorpyrifos; D009584:Nitrogen