{"topic_id":"exotic_tox_amphibian_metals","category":"exotic-pet-toxicology","context":"---\ntopic_id: exotic_tox_amphibian_metals\ncategory: exotic-pet-toxicology\ntitle: \"Metal (Cu, Cd, Zn, Ni, Pb) contaminant toxicity in amphibian tadpoles — environmental hazard\"\nlang: en\nsource: \"Acute toxicity of metals in Rhinella diptycha and Leptodactylus fuscus at different temperatures: a perspective for tropical tadpoles. Ecotoxicology. PMC13282347 (SpringerOpen).\"\nsource_file: pdf-raw/exotic-toxicology/amphibian_metals.txt\ndate_parsed: 2026-07-29\ntokens_estimated: 0\nverified: true\nverification: c1_substring\nsource_document: \"Acute toxicity of metals in Rhinella diptycha and Leptodactylus fuscus at different temperatures: a perspective for tropical tadpoles. Ecotoxicology. PMC13282347 (SpringerOpen).\"\ncitation:\n  authority: \"Europe PMC open-access veterinary literature\"\n  title: \"Metal (Cu, Cd, Zn, Ni, Pb) contaminant toxicity in amphibian tadpoles — environmental hazard\"\n  url: \"https://europepmc.org/article/PMC/PMC13282347\"\n  retrieved: \"2026-07-29\"\n  ref: \"exotic_tox_amphibian_metals\"\n  doc_type: \"peer-reviewed open-access article\"\n  needs_review: false\n---\n\n# Metal (Cu, Cd, Zn, Ni, Pb) contaminant toxicity in amphibian tadpoles — environmental hazard\nVerbatim first-hand facts from an open-access veterinary source. All bullets are exact substrings of the cited source file and C1-substring verified.\n## Toxicology facts\n- Some organisms are particularly sensitive to metal contamination, and amphibians are especially vulnerable due to their highly permeable skin and their occurrence in small aquatic habitats where pollutants may accumulate (Greulich and Pflugmacher 2003; Yan et al. 2008; Freitas et al. 2022). Furthermore, amphibian metamorphosis and developmental stability can be strongly influenced by environmental factors, including biotic, abiotic, and anthropogenic stressors such as predation, population density, water pH, temperature, and chemical exposure (Denver 1997; Freitas et al. 2016; Costa et al. 2017). Several amphibian species have been documented in anthropized areas and the presence of contaminants in their habitats has been directly linked to population declines worldwide (Hayes et al. 2010; Egea-Serrano et al. 2012; Thambirajah et al. 2019; IUCN 2025). This concern is reinforced by the latest red list published by the International Union for Conservation of Nature (IUCN), which reports that at least 41% of amphibian species are threatened, with highly endemic regions such as Brazil’s Atlantic Forest particularly at risk (Luedtke et al. 2023).\n- Exposure to metals can disrupt metamorphosis, impair physiological and immune functions, induce malformations, cause oxidative stress and genotoxicity, and negatively affect amphibian behavior and reproduction (Calfee and Little 2017; Do Amaral et al. 2019; Pinelli et al. 2019; Carvalho and Pinto-Vidal 2024; Costa et al. 2024). Despite evidence of their multi-pathway toxicity to amphibians, critical baseline data for metals, such as environmentally relevant concentration thresholds for most species, remain unknown. Additionally, the lack of standardized protocols for ecotoxicological assays on tropical amphibian larvae has led to the use of international guidelines developed for species from temperate regions, as Amphibian Metamorphosis Assay (AMA) (OECD, 2009) and Frog Embryo Teratogenesis Assay (FETAX) (NTP 2000), resulting in experimental conditions that often do not reflect the species’ natural habitats. Similarly, ABNT NBR 15,088 and ABNT NBR 15,499, developed for fish and commonly used as surrogate protocols to assess chemical lethality in tadpoles, prescribe an environmental temperature of 25–26 ± 2 °C. Nonetheless, temperatures of up to 42 °C have been recorded in habitats of native tadpoles in Brazil (Freitas et al. 2016; unpublished data collected between 2024 and 2025), and similar conditions are likely to occur in other warm regions worldwide, particularly in temporary ponds that serve as breeding sites for many amphibian species.\n- Tadpoles can bioaccumulate metals by direct absorption across their gills and skin, and by ingesting contaminated sediment during foraging (Yologlu and Ozmen 2015; Wei et al. 2015; Dubaissi et al. 2018; Guezgouz et al. 2021). Their gills are particularly effective at metal uptake because the epithelial surface is negatively charged by phospholipids, facilitating attraction of metal ions from the surrounding water (Wittmann 1981; Pagenkopf 1983). Once inside the organism, metals enter cells through ionic and molecular mimicry by using transporters meant for essential ions and organic molecules, as well as by some carrier proteins metals (Ballatori 2002; Bridges and Zalups 2005). As mentioned before, metals can cause a cascade of adverse effects in amphibians, including oxidative stress (Carvalho et al. 2020; Fernandes et al. 2021), increased metallothioneins (Yologlu and Ozmen 2015; Carvalho et al. 2017; Carlsson and Tydén 2018), neurotoxicity (Nunes 2011; Ossana et al. 2013), genotoxicity and mutagenicity (Monteiro et al. 2018; Patar et al. 2021; Costa et al. 2024), disrupted metamorphosis (Sun et al. 2017; Ya et al. 2021; Costa et al. 2024), hepatotoxicity and metabolic alterations (Shi et al. 2018; Ju et al. 2020; Pinto-Vidal et al. 2022), thyroid toxicity (Sun et al. 2017), and behavioral changes (Ranatunge et al. 2012; Hu et al. 2019). Even following acute exposure in our study, numerous Pb-exposed tadpoles exhibited edema (Fig. 1), indicating an excessive liquid accumulation caused by a disruption of osmotic regulation or inflammation in contaminated animals. This external morphological abnormality has already been observed in some metal-exposed tadpoles species, such as Rana luteiventris exposed to Cd (Lefcort et al. 1998), Bufo gargarizans exposed to Cu (Xia et al. 2012) and Xenopus laevis exposed to Zn (Martini et al. 2012).\n","sources":["exotic-pet-toxicology — Metal (Cu, Cd, Zn, Ni, Pb) contaminant toxicity in amphibian tadpoles — environmental hazard (retrieved 2026-07-29)"],"source":{"authority":"exotic-pet-toxicology","title":"Metal (Cu, Cd, Zn, Ni, Pb) contaminant toxicity in amphibian tadpoles — environmental hazard","url":"https://europepmc.org/article/PMC/PMC13282347","retrieved":"2026-07-29","ref":"","doc_type":"official PDF","source_document":"Acute toxicity of metals in Rhinella diptycha and Leptodactylus fuscus at different temperatures: a perspective for tropical tadpoles. Ecotoxicology. PMC13282347 (SpringerOpen).","verification_file":"pdf-raw/exotic-toxicology/amphibian_metals.txt"},"source_document":"Acute toxicity of metals in Rhinella diptycha and Leptodactylus fuscus at different temperatures: a perspective for tropical tadpoles. Ecotoxicology. PMC13282347 (SpringerOpen).","source_file":"pdf-raw/exotic-toxicology/amphibian_metals.txt","tokens_estimated":1055,"generated_at":null,"tip":"Use /api/v1/topics to discover more topics. /api/v1/nutrient for precise single-point queries. /api/v1/cross_compare for 2-3 standard comparisons."}