Morphological abnormalities in natural populations of the common South American toad Rhinella arenarum inhabiting fluoride-rich environments

OTERO, MANUEL A.; FLORES, PATRICIA; MARTINO, ADOLFO; POLLO, FAVIO; GRENAT, PABLO R.; GRISOLIA, MARTA; BIONDA, CLARISA; BABINI, MARIA SELENE; SALAS, NANCY E.

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2019 vol. 177 p. 32 - 38

0147-6513

Morphological abnormalities in amphibians may be attributed tocontaminants, ultraviolet radiation and trematode parasites, or asynergistic effect between them. In the present study, morphologicalabnormalities in Rhinella arenarum adults from natural and artificialfluoride-rich environments were identified and evaluated. Three siteswere sampled in central Argentina: Los Vallecitos stream (LF-LV), LosCerros Negros stream (MF-CN), and Decantation ponds (HF-DP), with low(0.33 mg/l), middle (2.03 mg/l) and high (14.0 mg/l) fluoride levelsrespectively; the latter site is associated with a fluoride mine.Abnormal individuals were photographed and then standard radiographs weretaken. Abnormality frequencies and relative percentage of abnormalindividuals were calculated for each site. In addition, skeletochronologywas used to estimate toad´s age. Five abnormality types were identified:syndactyly, ectrodactyly, polydactyly, microphthalmia and ectromelia.Percentages of abnormal individuals per site were: LF-LV=4%, MF-CN=21.2%and HF-DP=6.4%. The MF-CN and HF-DP populations had morphologicalabnormality frequencies that exceeded the reference value (5%) reportedin the literature. The average age did not differ between sites. Theresults of this study indicate that there is an association betweenfrequency of morphological abnormalities and high fluoride levels.