TY - JOUR
T1 - Bioaccumulation potential of chlorpyrifos in resistant Hyalella azteca
T2 - Implications for evolutionary toxicology
AU - Johanif, Nadhirah
AU - Huff Hartz, Kara E.
AU - Figueroa, Alexandra E.
AU - Weston, Donald P.
AU - Lee, Devon
AU - Lydy, Michael J.
AU - Connon, Richard E.
AU - Poynton, Helen C.
N1 - Funding Information:
This work was supported by a grant from the California Department of Fish and Wildlife ( CDFW #P1796002 to REC, HCP, and MJL) and by a National Science Foundation Research Experience for Undergraduates (REU) award ( OCE-1658901 to HCP). We also thank thesis committee members, William Robinson and Luis DeLeon for guidance on experimental design and review of earlier versions of this manuscript.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/11/15
Y1 - 2021/11/15
N2 - Given extensive use of pesticides in agriculture, there is concern for unintended consequences to non-target species. The non-target freshwater amphipod, Hyalella azteca has been found to show resistance to the organophosphate (OP) pesticide, chlorpyrifos, resulting from an amino acid substitution in acetylcholinesterase (AChE), suggesting a selective pressure of unintended pesticide exposure. Since resistant organisms can survive in contaminated habitats, there is potential for them to accumulate higher concentrations of insecticides, increasing the risk for trophic transfer. In the present study, we estimated the uptake and elimination of chlorpyrifos in non-resistant US Lab, and resistant Ulatis Creek (ULC Resistant), H. azteca populations by conducting 24-h uptake and 48-h elimination toxicokinetic experiments with 14C-chlorpyrifos. Our results indicated that non-resistant H. azteca had a larger uptake clearance coefficient (1467 mL g−1 h−1) than resistant animals (557 mL g−1 h−1). The half-life derived from the toxicokinetic models also estimated that steady state conditions were reached at 13.5 and 32.5 h for US Lab and ULC, respectively. Bioaccumulation was compared between non-resistant and resistant H. azteca by exposing animals to six different environmentally relevant concentrations for 28 h. Detection of chlorpyrifos in animal tissues indicated that resistant animals exposed to high concentrations of chlorpyrifos were capable of accumulating the insecticide up to 10-fold higher compared to non-resistant animals. Metabolite analysis from the 28-h concentration experiments showed that between 20 and 50 % parent compound was detected in H. azteca. These results imply that bioaccumulation potential can be more significant in chlorpyrifos resistant H. azteca and may be an essential factor in assessing the full impacts of toxicants on critical food webs, especially in the face of increasing pesticide and chemical runoff.
AB - Given extensive use of pesticides in agriculture, there is concern for unintended consequences to non-target species. The non-target freshwater amphipod, Hyalella azteca has been found to show resistance to the organophosphate (OP) pesticide, chlorpyrifos, resulting from an amino acid substitution in acetylcholinesterase (AChE), suggesting a selective pressure of unintended pesticide exposure. Since resistant organisms can survive in contaminated habitats, there is potential for them to accumulate higher concentrations of insecticides, increasing the risk for trophic transfer. In the present study, we estimated the uptake and elimination of chlorpyrifos in non-resistant US Lab, and resistant Ulatis Creek (ULC Resistant), H. azteca populations by conducting 24-h uptake and 48-h elimination toxicokinetic experiments with 14C-chlorpyrifos. Our results indicated that non-resistant H. azteca had a larger uptake clearance coefficient (1467 mL g−1 h−1) than resistant animals (557 mL g−1 h−1). The half-life derived from the toxicokinetic models also estimated that steady state conditions were reached at 13.5 and 32.5 h for US Lab and ULC, respectively. Bioaccumulation was compared between non-resistant and resistant H. azteca by exposing animals to six different environmentally relevant concentrations for 28 h. Detection of chlorpyrifos in animal tissues indicated that resistant animals exposed to high concentrations of chlorpyrifos were capable of accumulating the insecticide up to 10-fold higher compared to non-resistant animals. Metabolite analysis from the 28-h concentration experiments showed that between 20 and 50 % parent compound was detected in H. azteca. These results imply that bioaccumulation potential can be more significant in chlorpyrifos resistant H. azteca and may be an essential factor in assessing the full impacts of toxicants on critical food webs, especially in the face of increasing pesticide and chemical runoff.
KW - Bioaccumulation
KW - Hyalella azteca
KW - Non-target
KW - Organophosphate
KW - Pesticide resistance
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U2 - 10.1016/j.envpol.2021.117900
DO - 10.1016/j.envpol.2021.117900
M3 - Article
C2 - 34391048
AN - SCOPUS:85112199302
VL - 289
JO - Environmental Pollution
JF - Environmental Pollution
SN - 0269-7491
M1 - 117900
ER -