Effect on growth and development of common toad (Rhinella arenarum) tadpoles in environment related to fluorite mine

OTERO, MANUEL A.; GRENAT, PABLO R.; POLLO, FAVIO E.; BARAQUET, MARIANA; MARTINO, ADOLFO L.

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2023

0048-9697

Fluorite mining activities have been scarcely evaluated so far and the potential effect of thisactivity on larval stages is poorly known. Thus, studies addressing the effect ofcontaminants present in water bodies on the health of amphibian larvae are crucialinformation for their conservation and constitute a warning sign of environmentalmodification. This study aims to evaluate the effects of natural and artificial surface watersassociated with a fluorite mine on the early life stages of Rhinella arenarum. Usingmicrocosms, we assessed four sites with different degrees of disturbance by the fluorinemine: Vallecitos stream (undisturbed); Cerros Negros upstream of mining camp (lowdisturbance); Cerros Negro downstream of mining camp (medium disturbance);Decantation Ponds (high disturbance). For 65 days we measured different endpoints atdifferent periods of tadpole development. The highest mortality of tadpoles was observed inthe Decantation Ponds. In the same way, larval body condition was lower at DecantationPonds throughout the study. due mainly to the lower weight. A significant decrease ingrowth and development was observed in Cerros Negro downstream of the mining campand Decantation Ponds. No significant differences in growth, development and mortalitywere observed for the other two sites. At metamorphic climax we observe a lower bodycondition and a reduced recruitment of individuals in Decantation Ponds. This studyallowed us to assess the effect on larvae of R. arenarum of fluorite mining wastewatercompared with other near natural sites. Given the potentially negative synergic effects ofmixed water pollutants on tadpole, this study suggests that chronic exposure in fluoritemining water may significantly impact the adult amphibian population structure, thusaltering population viability. Therefore, we propose to monitor the correct functioning ofthe mine and especially of Decantation Ponds to avoid discharges into the natural streams.