Differential Uptake of Endosulfan in the South American Toad Under Sublethal Exposure

Abstract

Agroecosystems are usually polluted with a wide variety of contaminants with pesticides being very frequently detected. Endosulfan, an organochlorine pesticide, has been shown to cause both lethal and sublethal effects on aquatic organisms such as amphibians and especially on its early developmental stages. In this context, the aim of this study was to evaluate the uptake of environmentally relevant concentrations of endosulfan and its correlation with differential sensitivity in the early development stages of the common South American toad, Rhinella arenarum. Embryos and larvae were exposed to sublethal concentrations of endosulfan for several periods of exposures. According to the developmental stage at which they were exposed, the uptake rate was different. Bioconcentration factors (BCFs) for embryos significantly decreased with exposure time and concentration (p < 0.05) reaching a BCF of ≤1679 for embryos at 96 h of exposure to 0.001 mg endosulfan L(-1). BCFs for larvae significantly increased with exposure time (p < 0.05) obtaining a maximum of 40 at 504 h. In our previous study, we reported that embryos were less sensitive to the effects of endosulfan than larvae, which is in line with the main tendency of embryos to bioconcentrate endosulfan as observed in this study.

Sublethal Effects of Dermal Exposure to Poly‐ and Perfluoroalkyl Substances on Postmetamorphic Amphibians

“…Given that most environmental exposures to chemical contaminants are expected to be below levels known to directly cause mortality in wildlife, research has increasingly focused on the broad range of sublethal effects that can follow exposure (Köhler and Triebskorn 2013). For instance, chemical exposure can reduce growth and development, alter behavior, or impair immune function (Lance et al 2012; Svartz et al 2015; Gardner and Oberdorster 2016). These effects have been observed with contaminants such as pesticides and heavy metals (Colborn et al 1993; Grue et al 1997; Boening 2000; Watson et al 2009).…”