Developmental and interactive effects of arsenic and chromium to developing Ambystoma maculatum embryos: Toxicity, teratogenicity, and whole-body concentrations

Abstract

Anthropogenic activity has contributed to elevated environmental concentrations of arsenic (As) and chromium (Cr). The spotted salamander, Ambystoma maculatum, may be useful for identifying developmental effects produced by exposure to these contaminants as adults breed and larvae develop in water that may contain As or Cr. Three sample sets among 700 developing larvae were exposed to a range of As, Cr, or 2.5:1 mixture of As:Cr concentrations, respectively. From these 700 larvae, samples containing approximately 24 larvae showed different patterns of whole-body As and Cr from individual and mixture exposure. Whole-body As concentrations were 20.27 and 45.4 µg/g dry weight for larvae exposed to 20 mg/L As and 25:10 mg/L As:Cr, respectively, while whole-body Cr concentrations were 24.8 and 22 µg/g dry weight for larvae exposed to 20 mg/L Cr and 25:10 As:Cr, respectively. Observed malformations included edema, tail kinking, facial deformities, and abnormal bending. Twelve-day lethal concentrations for As and Cr in Ambystoma maculatum larvae were 261.17 mg/L and 71.93 mg/L, respectively, while 12-d effective concentrations to induce malformations were 158.82 and 26.05 mg/L, giving teratogenic indices of 1.64 and 2.76 for individual metal exposure. Exposure to a mixture of As and Cr resulted in a response addition and yielded lower lethal and effective concentration values with a teratogenic index of 2.78, indicating that these contaminants are developmentally toxic at lower concentrations when exposed as a mixture. Data demonstrate that As and Cr affect development of amphibian larvae, and that Ambystoma maculatum may be a useful indicator of environmental toxicity for these metals.

Monitoring of toxicity of As(V) solutions by AMPHITOX test without and with treatment with zerovalent iron nanoparticles

“…Also, embryos of X. laevis, exposed to As(V), developed ventral edema (Gornati et al, 2002), but compared with other amphibians, the sensitivity to As(V) was lower. This As(V) effect was also reported for A. maculatum larvae (Gardner et al, 2017), while Sun et al (2016) informed pericardium edema in larvae fishes exposed to the metalloid. The As-induced nephron damage and the disruption of Na / K ATPase (the "sodium pump") as underlying biochemical mechanism of As could be related to this particular adverse effect (Mingai et al, 2009).…”

“…In previous works, musculoskeletal disorders similar to those found here for R. arenarum, as tail curvatures in fish larvae exposed to As(V), have been described (Sun et al, 2016). Also, flexures, tail kinking, facial deformities and abnormal bending of As(V) on developing salamanders, Ambystoma maculatum, were recently informed by Gardner et al (2017). Gornati et al (2002) reported acaudia (loss of the tail) in X. laevis embryos exposed to As(V).…”

“…It is well known that there is a differential susceptibility of living organisms to both As chemical species, As(III) and As(V), with the first form shown to be more toxic than the latest one (Gardner et al, 2017;Ventura-Lima et al, 2011). While As(III) dominates in reducing environments such as groundwater, As(V) is dominant in oxidizing environments such as surface waters (Chen et al, 2009), where amphibians live and breed.…”

Inhibition of Metamorphosis, Thyroid Gland, and Skeletal Ossification Induced by Hexavalent Chromium in Bufo gargarizans Larvae

“…The latter is severely toxic to aquatic organisms (Mishra and Bharagava 2016). There is evidence that Cr (VI) exposure can result in malformations, growth inhibition, and histopathological alterations of amphibians (Gardner et al 2017; Monteiro et al 2018). Historically, Cr (VI) was released into aquatic environments through a variety of industrial activities, such as effluents discharged from textiles, leather tanning, metal finishing, chrome electroplating, and printing industries (Taju et al 2017).…”

Neuroendocrine disruption of organizational and activational hormone programming in poikilothermic vertebrates

“…In amphibians embryogenesis is ex vivo, their skin is permeable and they go through metamorphosis. For these reasons, amphibians are considered highly sensitive test organisms for hormone-dependent development (Tata 2006) and employed in ecotoxicological assessments (Santos et al 2015; Correia et al 2014; Maselli et al 2010; da Rosa, 2016; Gardner et al, 2017), including standard methods such as the Amphibian Metamorphosis Assay (OECD), and the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) (ASTM). Anuran metamorphosis, and in particular the neuroendocrine control of the process, may represent a reliable model system to examine NED; since it is a process dependent upon TH consisting of thyroxine (T4) and triiodothyronine (T3) (Ishizuya-Oka 2011; Sachs et al 2000), and considered equivalent to postembryonic organogenesis in mammals (Tata 2006).…”