Individual and Combined Effects of Current-Used Fungicides in Fish: Bioaccumulation and Oxidative Stress Responses.

FANTON N; CAZENAVE J; REPETTI, MARÍA R.; MICHLIG, MELINA P.; MORA C.; CAMPANA M.; ALE A., ROSSI A., BACCHETTA C., DE LA TORRE F., CAZENAVE J.

Congreso; VII Setac Latin America 14 Biennal Meeting.; 2021

SETAC

The intensive use of fungicides to maximize rice yields and control crop pests may pose a risk to fish inhabiting paddies. The aim of this study was to evaluate the effect, either individually or combined, of two fungicides commonly used in rice fields on bioaccumulation and oxidative stress in the freshwater fish Prochilodus lineatus. Juveniles (3.4 ± 1.1 g; 6.9 ± 0.7 cm total length) were exposed for 96 h to environmentally relevant concentrations, a low (1) and a high (2), of azoxystrobin (AZO-1 = 10 μg L-1, AZO-2 = 100 μg L-1) and cyproconazole (CYP-1 = 4 μg L-1, CYP-2 = 40 μg L-1), individually and in mixture (active principles and a commercial formulation). The fungicide concentrations and mixtures (ratio 70:30, AZO:CYP) were selected based on literature data and a previous sampling in a rice field. Treatments tested at triplicate were: AZO-1, AZO-2, CYP-1, CYP-2, mixture low M-1 (AZO-1 + CYP-1) and mixture high M-2 (AZO-2 + CYP-2). Besides, similar fungicide mixture treatments were assayed with a commercial formulation: F-1 y F-2. In addition, a negative control (NC) and a solvent control (SC) were tested. Bioaccumulation analyses were performed on whole fish due to their small size. Superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) enzyme activities, as well as levels of lipid peroxidation (LPO) were evaluated in gills and muscle. Results showed that no significant differences were observed between NC and SC. Fish exposed to the higher concentrations (individually and in mixtures) bioaccumulated more fungicides than those exposed to the lower ones. No significant differences were observed among individual and mixture treatments within the same concentration levels. Alteration of tissue antioxidant defenses in muscle tissue was observed, mainly through SOD and GST activities which were significantly decreased in all experimental groups. In turn, muscle oxidative damage was present in fish at all treatments. By contrast, gills antioxidant enzyme response was variable among groups, except for GST activity which also decreased at all treatments. Increased gills LPO were only observed in M-C1. In conclusion, environmentally relevant concentrations of AZO and CYP accumulate and cause oxidative stress in P. lineatus, both individually and in combination. Gills were less sensitive than muscle tissue to fungicide exposure and similar effects were produced by the mixture of active principles and the commercial formulation.