Low Levels of Sodium and Potassium in the Water from Wetlands in Minnesota that Contained Malformed Frogs Affect the Rate ofXenopusDevelopment

Abstract

Water samples were collected between 1999 and 2000 from wetlands in Minnesota that contained malformed frogs. The water samples were analyzed for 14 minerals/ions and screened for the presence of biologically active compounds using Xenopus laevis. Results indicated that water from two sites, CWB and ROI2, induced severe retardation with embryo lengths reduced 20% after 96 hr of development. The developmental delay observed with water from ROI2 was alleviated by supplementation with sodium, while both sodium and potassium alleviated the developmental delay observed with water whose mineral content mimicked that of CWB. Seasonal fluctuations in the sodium and potassium content at ROI2 and NEY correlated with changes in the rates of Xenopus development. Xenopus embryos reared on water from ROI2 for 120 hr displayed gut malformations not present in embryos reared on a synthetic media designed to mimic the mineral content of the water from ROI2. Embryos reared on water from ROI2 supplemented with minerals at levels comparable to that routinely employed in the rearing of Xenopus were neither retarded nor malformed. It is proposed that climate driven hydrology may influence the mineral composition at selected wetlands and delay development which may alter window(s) of susceptibility towards biologically active agents and the occurrence of malformed frogs.

Acute Ecotoxicity Potential of Untreated Tannery Wastewater Release in Arequipa, Southern Peru

“…Exposure to metals such as zinc, copper, lead, and cadmium has previously been shown to reduce tadpole survival before metamorphosis [84], as well as other negative effects on the development of embryos and larvae of Xenopus laevis in South Africa [93]; in comparison with the present investigation, the concentrations of these metals are lower in the tested dilutions than for those other studies. Other investigations [94,95] report that metals such as sodium, calcium, potassium, and manganese can generate lethal effects and morphological alterations in the development of amphibian embryos, findings similar to the results obtained in this research.…”

Amphibians and agricultural chemicals: Review of the risks in a complex environment

“…Although subsequent laboratory studies implicated a developmental contaminant (Burkhart et al, 1998;Fort et al, 1999aFort et al, ,b, 2001Bridges et al, 2004) and identified numerous agricultural pollutants within water from sites where frog deformities occurred (Fort et al, 1999b), no single causative agent could be identified. To further complicate the issue, there was also some suggestion that mineral deficiencies in the water at sites where malformations occurred may be a contributing factor (Fort et al, 1999b;Tietge et al, 2000;Garber, 2002;Garber et al, 2004).…”

Assimetria Flutuante Em Organismos Aquáticos E Sua Aplicação Para Avaliação De Impactos Ambientais

“…A ampla ocorrência de anfíbios com deformidades e a importância da água doce na cadeia alimentar vêm gerando um aumento da preocupação da sociedade com a saúde pública. Várias hipóteses têm sido propostas para explicar essas deformidades, incluindo o aumento da exposição aos raios ultravioletas-B devido à diminuição da camada de ozônio, predação, fragmentação de hábitats, escassez de alimento, aumento da exposição a parasitas, poluentes e retinóides (Blaustein et al 1997, Sessions et al 1999, Pounds 2001, Garber et al 2004.…”