ISSN:
1432-0703
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Medicine
Notes:
Abstract This study was carried out to determine 1) the minimum concentration at which the fungicide ethylenebisdithiocarbamate disodium salt (nabam) would induce malformations in developingXenopus laevis embryos, 2) whether nabam in solution retained toxicological and teratogenic effects over long periods of time, 3) to compare the toxic and teratogenic effects of nabam's degradative products ethylene thiourea and ethylene diamine, 4) to compare toxic and teratogenic effects of the related substances methyl isothiocyanate and sodium thiocyanate, and 5) to compare the effects of combinations of these substances.Xenopus laevis embryos at “yolk plug” stage (Nieukoop and Faber stages 10–12) were exposed to various concentrations of fresh and one- to seven-week old nabam solutions, ethylene thiourea, ethylene diamine, methyl isothiocyanate, sodium thiocyanate, and combinations of some of these substances. Fresh nabam solutions induced malformations of the notochord in a majority of embryos at concentrations as low as 40 Μg/L. Embryos treated with 40 Μg/L nabam stored 1–7 weeks developed normally. Embryos treated with 100 Μg/L nabam stored 1–7 weeks developed severe malformations of the notochord, delayed pigmentation of the eye, and increased mortality. In addition, embryos exposed to 100 Μg/L nabam stored 4–7 weeks also experienced delayed development of the gut and a general decrease in size. Embryos exposed to fresh 100 Μg/L nabam solutions developed only malformations of the notochord. Concentrations of methyl isothiocyanate of less than 1.0 Μg/L were sublethal. Methyl isothiocyanate (1.0–1,000 Μg/L) was extremely toxic with 100% mortality recorded by day 7 in all groups. Sodium thiocyanate, ethylene thiourea, and ethylene diamine (100–10,000 Μg/L) were neither toxic nor teratogenic. Combinations of ethylene thiourea and methyl isothiocyanate at or beyond 5,000 Μg/L, or 1.0 Μg/L respectively were acutely lethal. At concentrations of 100–1,000 Μ/L ethylene thiourea and 0.01–0.1 Μg/L methyl isothiocyanate, the tadpoles that hatched had swollen and kinked notochords, similar to animals exposed to fresh 40 Μg/L nabam. Thus, the aquatic environment when contaminated with very low levels of the fungicide nabam is hazardous to the development of amphibian embryos.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01054910
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