Mortality, Immobility and Biochemical Acute Effects of Thiacloprid on Two Populations of Hyalella Curvispina Amphipods From North Patagonia Argentina

KIRILOVSKY, EVA R.; CARRASCO, NATACHA; BONGIOVANNI, GUILLERMINA A.; ANGUIANO, OLGA L.; FERRARI, ANA

Virtual

Congreso; Latin America 14th Biennial Meeting SETAC; 2021

the Society of Environmental Toxicology and Chemistry (SETAC)

Thiacloprid (TCP) is a neonicotinoid insecticide widely used in theValley of Río Negro River as pest control for fruit production. The aimof this study was to evaluate TCP acute effects in two differentpopulations of the amphipod Hyallela curvispina, from a pristine site(LB) and an agricultural one (FO) located in North Patagonia Argentina.Both populations have shown differences in susceptibility toanticholinesterasic insecticides in previous studies. Amphipods from LBand FO were exposed to increasing concentrations (0-100 mg/L) of TCP(Calypso ®, Bayer), lethality and immobility were measured every 24 hfor four days and 96 h LC50 and EC50 values were determined. Inaddition, amphipods were exposed to sublethal and lethal concentrationsof TCP (LB: 0.02-2, FO: 0.02-100 mg/L), and enzymatic activity ofglutathione-S-transferase (GST) and carboxylesterase (CE), and reducedglutathione content (GSH) were measured spectrophotometrically insurviving individuals at 48 and 96 h. TCP 96h-LC50 for LB was 0.42(0.21-0.78) mg/L, while for FO it was 44.2 (15.6-134.8) mg/L, twoorders of magnitude higher. Immobility 96h-EC50 value for LB was0.14 (0.07-0.23) mg/L, and for FO, 0.14 (0.06-0.26) mg/L. GST activityin LB was not significantly affected by TCP. In FO it showed atendency to increase at 2 mg/L and a significant increase with 20 and100 mg/L (50 and 60% vs. control), and after 96 h with 0.2 and 2 mg/L(42 and 35%). There were no significant differences in CE activity inLB after 48 h, while all tested concentrations decreased after 96 h (48,53 and 51%, respectively). CE activity increased in FO after 48 hexposure to 0.2; 2 and 100 mg/L TCP (28, 93 and 57 %, respectively)while no significant differences with controls were observed after 96 h.No significant differences were found in GSH content between exposedand control amphipods from both populations. Higher LC50 levels inFO compared to LB could be a sign of tolerance to TCP due to a historyof use in this agricultural frame. However, both populations showed thesame immobility response, which would most likely hinder the chancesof survival in the wild. This highlights the importance of immobility as abiomarker of effect. The increase in GST and CE activities, even atsublethal concentrations, could be linked to a protective response in FOamphipods. The results obtained in this study constitute further evidenceof the impact from continued neonicotinoid applications onautochthonous species.