Over the last few years, the hazards associated with the extensive use of fungicides have become an issueof great concern but, at present, the effects of these substances on amphibians remain poorly understood.The goal of the present study was to assess the effects of two commonly used fungicides, tebuconazoleand pyrimethanil, on Italian Tree Frog (Hyla intermedia), a species frequently found in agricultural areas.Tadpoles were exposed to fungicides from developmental Gosner stage 25 (GS 25) to completion ofmetamorphosis (GS 46) and the whole exposure period lasted 78 days. For both tested fungicides weused two concentrations (5 and 50 g/L) that are comparable to those detected in surface waters, nearagricultural fields.A variety of sublethal effects—on growth, development, behavior, and physiology—may be used forevaluating alterations induced by pollutants in amphibians. We estimated whether pyrimethanil andtebuconazole exposure impacted on H. intermedia life history traits. For this purpose, survival, growth,development, initiation of metamorphosis, success and size at metamorphosis, time to metamorphosis,and frequency of morphological abnormalities were evaluated. We showed, for all considered endpoints,that the exposure to tebuconazole exerts more harmful effects on H. intermedia than does exposure topyrimethanil.Before the onset of metamorphic climax we showed, for both fungicides, that the low concentrations(5 g/L) induced significantly greater effects than the higher ones (50 g/L) on survival and deformityincidence. During the metamorphic climax, a complete reversal of this nonlinear trend takes place,and the percentage of animals initiating metamorphosis was reduced in fungicide-exposed groups in aconcentration-dependent manner. Furthermore, a strong correlation emerged between fungicide expo-sure and the incidence of morphological abnormalities such as tail malformations, scoliosis, edema,mouth and limb deformities.Exposure to tested fungicides also caused a reduction in developmental rates just prior to the onset ofmetamorphic climax, which translated to a significant delay in timing of metamorphosis. We detecteda drastic decrease in the success at metamorphosis in all exposed groups, compared to control group(86.25%). In fact, the percentage of survived larvae to GS 46, in the high and low concentrations, respec-tively, was only 22.5% and 36.25% in tebuconazole-exposed groups and 43.75% (50 g/L) and 56.25%(5 g/L) in pyrimethanil-exposed groups.Our findings underscore the hazardous properties of these two fungicides for non-target species in thecontext of ecotoxicological risk assessment. No published studies have addressed the long-term effectsof tebuconazole and pyrimethanil on amphibians. To date, this is one of only a few studies documentingthe effects of fungicide exposure over the whole larval development.

Effects of long-term exposure to two fungicides, Pyrimethanil and Tebuconazole, on survival and life history traits of Italian tree frog (Hyla intermedia).

Bernabò, I;Guardia, A;Macirella, R;Sesti, S;Crescente, A;BRUNELLI, Elvira
Project Administration
2016

Abstract

Over the last few years, the hazards associated with the extensive use of fungicides have become an issueof great concern but, at present, the effects of these substances on amphibians remain poorly understood.The goal of the present study was to assess the effects of two commonly used fungicides, tebuconazoleand pyrimethanil, on Italian Tree Frog (Hyla intermedia), a species frequently found in agricultural areas.Tadpoles were exposed to fungicides from developmental Gosner stage 25 (GS 25) to completion ofmetamorphosis (GS 46) and the whole exposure period lasted 78 days. For both tested fungicides weused two concentrations (5 and 50 g/L) that are comparable to those detected in surface waters, nearagricultural fields.A variety of sublethal effects—on growth, development, behavior, and physiology—may be used forevaluating alterations induced by pollutants in amphibians. We estimated whether pyrimethanil andtebuconazole exposure impacted on H. intermedia life history traits. For this purpose, survival, growth,development, initiation of metamorphosis, success and size at metamorphosis, time to metamorphosis,and frequency of morphological abnormalities were evaluated. We showed, for all considered endpoints,that the exposure to tebuconazole exerts more harmful effects on H. intermedia than does exposure topyrimethanil.Before the onset of metamorphic climax we showed, for both fungicides, that the low concentrations(5 g/L) induced significantly greater effects than the higher ones (50 g/L) on survival and deformityincidence. During the metamorphic climax, a complete reversal of this nonlinear trend takes place,and the percentage of animals initiating metamorphosis was reduced in fungicide-exposed groups in aconcentration-dependent manner. Furthermore, a strong correlation emerged between fungicide expo-sure and the incidence of morphological abnormalities such as tail malformations, scoliosis, edema,mouth and limb deformities.Exposure to tested fungicides also caused a reduction in developmental rates just prior to the onset ofmetamorphic climax, which translated to a significant delay in timing of metamorphosis. We detecteda drastic decrease in the success at metamorphosis in all exposed groups, compared to control group(86.25%). In fact, the percentage of survived larvae to GS 46, in the high and low concentrations, respec-tively, was only 22.5% and 36.25% in tebuconazole-exposed groups and 43.75% (50 g/L) and 56.25%(5 g/L) in pyrimethanil-exposed groups.Our findings underscore the hazardous properties of these two fungicides for non-target species in thecontext of ecotoxicological risk assessment. No published studies have addressed the long-term effectsof tebuconazole and pyrimethanil on amphibians. To date, this is one of only a few studies documentingthe effects of fungicide exposure over the whole larval development.
Fungicides, Amphibians, Growth, Development, Metamorphosis, Tadpoles
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/151637
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