Biomarkers of genotoxicity and health status of Rhinella fernandezae populations from the lower Paraná River Basin, Argentina

Abstract

Anthropogenic activities may affect wild animal populations. Among them, amphibians are particularly sensitive to environmental change. The aim of this study was to evaluate the health condition of Rhinella fernandezae populations at three sites in the Buenos Aires Province, Argentina: a site inside a natural reserve (S1), a site surrounded mainly by industrial activities (S2) and a site surrounded principally by agriculture (S3). Sex and body condition (health status indicators), and micronuclei frequency (genotoxicity biomarker) of R. fernandezae adults were recorded to determine the health status of the local populations. Water samples were also analyzed for metals and pesticides to identify potential correlations with R. fernandezae malformations. Metals and pesticides were detected in the water samples of all three sites, with Al, Cu and Se exceeding the relevant limits for the protection of aquatic life. S1 had the highest overall environmental quality, and S2 had the greatest variety of pesticides. Individuals from S3 had significantly higher micronuclei frequency and females from S3 significantly lower body condition than females from S1, while females from S2 were significantly smaller than those from S1. Worst amphibian-based biological quality was assessed for S3, followed by S2 and S1. The low health status-fitness of females from the impacted sites (especially of the agriculture-surrounded S3 site), indicated by the low body condition and the high micronuclei frequency, may compromise the long-term health of the local amphibian populations. We conclude that action needs to be taken towards the long-term conservation of local amphibian populations from human-induced ecosystem degradation.