Acute toxicity and biochemical effects of azinphos methyl in the amphipod Hyalella curvispina

Abstract

We evaluated the acute toxicity and biochemical effects of the organophosphorus pesticide azinphos methyl (AM) in the amphipod Hyalella curvispina that inhabits ponds and irrigation channels of an intensive fruit-producing region in Rio Negro and Neuquén valley, North Patagonia, Argentina. The analysis by nonlinear regression of data from the 96 h-acute toxicity tests indicated the coexistence of two subpopulations of H. curvispina with different susceptibilities to AM. The 96 h-LC₅₀ for the resistant subpopulation (166 ± 56 μg/L) was 216-fold higher than the 96h-LC₅₀ value for the susceptible one (0.77 ± 1.33 μg/L).The two subpopulations could not be distinguished based on the biochemical measurements in control amphipods. Cholinesterase activity was significantly inhibited in AM-exposed amphipods in a concentration-dependent manner. The IC₅₀ value obtained after 96 h of exposure (2.18 ± 1.95 μg/L) was significantly lower than the 48 h-IC₅₀ value (29.6 ± 17.4 μg/L). Carboxylesterase activity was significantly inhibited after 48 h of exposure to 12.5 and 62.5 μg/L AM (inhibition, 51%). This enzyme was thus able to protect cholinesterase from inhibition at 12.5 μg/L AM. Reduced glutathione and catalase showed a significant increase after 24 h of exposure as an adaptive response to AM, whereas glutathione S-transferase activity was not significantly modified. The analysis of species sensitivity distribution showed that both subpopulations of H. curvispina were more tolerant to AM than most amphipod species, and that the susceptible subpopulation was more sensitive to AM than the other local aquatic species analyzed. The maximum concentration of AM in drainage water within the fruit-producing area reported by other studies would affect most of the amphipod species (99%) and also a 44% of local aquatic ones. The results obtained in this study point out the usefulness of including amphipods like H. curvispina in ecotoxicity studies and monitoring programs to perform pesticide risk assessments.

Joint Probabilistic Analysis of Risk for Aquatic Species and Exceedence Frequency for the Agricultural Use of Chlorpyrifos in the Pampean Region, Argentina

“…They report a decrease in macroinvertebrate abundance and taxon richness associated with a decrease in the sensitive taxon Betidae and an increase in some tolerant taxa such as Chironomidae and Gastropoda. On the other hand, the development of tolerant populations of H. curvispina has been reported in the same region as an adaptive response to organophosphorus pesticides and other contaminants (Anguiano et al 2014;Del Brio et al 2018).…”

Azinphos-methyl and chlorpyrifos, alone or in a binary mixture, produce oxidative stress and lipid peroxidation in the freshwater gastropod Planorbarius corneus

“…These insecticides can reach watercourses via runoff and spray drift and adversely affect aquatic invertebrate and vertebrate non-target species (USEPA, 2001;Gormley et al, 2005;Anguiano et al, 2012;Williams et al, 2014).…”

Metabolism, bioaccumulation, and toxicity of pesticides in aquatic insect larvae

“…Its specific activity (nmol/min/mg protein) seems to be lower in black flies , 57,58) the caddisfly (92), 56) and midges (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36), 47,59) as compared with D. magna (220) 60) and Hyalella curvispina (amphipod) (101). 61) Although the number of tested substrates is limited, the CaE activity decreased as follows: black fly>caddisfly≥mayfly>damselfly. 36) It is noted that the enzyme polymorphism is known for a few species.…”

“…Similar activity against CDNB has been reported for the D. magna (but no activity against DCNB) 65) and Hyalella spp. 61,66) The modified activities against CDNB and DCNB by exposure to pesticides have been examined mainly in Chironomus spp. Several OP, OC, and pyrethroid insecticides gave no or slightly increased activities (less than 1.4-fold), 46,48,56,59,62,67) while the induction of GST activities by a factor of around two was observed for metolachlor 47) and 2,4-D. 68) In the case of alachlor, activities reduced by about half most likely originated from the loss of glutathione by rapid conjugation, as supported by the increased GST gene expression.…”