ACUTE EXPOSURE OF THE NON TARGET ORGANISMS AT FUNGICIDE TERBINAFINE

Silvia Patrícia Carraschi1,2*, Ana Beatriz Kapp2; Isabella Alves Brunetti2; Claudinei da Cruz2, Maria José Tavares Ranzani-Paiva1
 
*Fapesp: funding, proc. no 2013/25113-2
1Fisheries Institute (São Paulo, SP) - Brazil. E-mail: patycarraschi@gmail.com
2Educational Foundation of Barretos (Barretos, SP) - Brazil

Mycotic diseases in fish are often caused by Saprolegnia sp. oomycete which causing destruction of the skin and fins due cellular necrosis by hyphal penetration in fish. So, it is emergency the molecules study to control this pathogen but for molecules prospection is necessary to know the ecotoxicological effects for non-target organisms. Thus, the aim of this research was to evaluate the acute toxicity of terbinafine for fishes Piaractus mesopotamicus and Hyphessobrycon eques and for aquatic plants Lemna minor, Azolla caroliniana and Wolffia sp.

Fishes and plants were aclimated in the bioassay room at 25 ± 2oC and initially, we performed sensitivity tests with reference substances for each organism. In the definitive toxicity tests, P. mesopotamicus was exposed to 20.0; 30.0; 45.0; 67.5; 101.2; 227.8; 341.7 mg L-1; H. eques to 3.43; 11.15; 36.26 and 117.8 mg L-1; L. minor to 0.1; 1.0; 10.0; 50.0; 350.0 and 1120 µg L-1; A. caroliniana to 0.1; 1.0; 3.5; 11.2; 36.5 and 118.0 mgL-1 and one control. The tests were conducted in static system, with three replicates where there were three fish, 12 fronds of Lemna, five plants of Azolla or plants in 0.3 mm of Wolffia per replicate. The fishes were exposed for 48 hours and the pants for seven days and in the end the LC50;48h values were calculated by Trimmed Spearman-Karber software. The LC50;48h of terbinafine for P. mesopotamicus was 58.96 mgL-1 (41.69 - 83.38 mg L-1); for H. eques was > 117.8 mgL-1 because there was no mortality; for L. minor, the LC50;7D was 10 ug L-1 (10 - 20 ug L-1) (Figure 1); for A. caroliniana, 4.35 mg L-1 (3,10 - 6,11 mg L-1) and for Wolffia sp. was > 118.0 mg L-1, because also there was no mortality of plants until this maximum concentration tested. The toxicity for P. mesopotamicus must be monitored in relation to exposure time because it is host of oomycete Saprolegnia which it will be controlled using terbinafine. Therefore, the best bioindicator for terbinafine toxicity is the plant Lemna minor because is more sensitive and classify this fungicide as extremely toxic (LC50 < 0.1 mg L-1).