Mercurium-zinc antagonism in Bufo arenarum embryos and Cnesterodon decemmaculatus
- Inst. de Ciencias Ambientales y Salud, Buenos Aires (Argentina). Programa de Seguridad Quimica
The identification of mercurium hazard for Cnesterodon decemmaculatus and Bufo arenarum (embryos) was evaluated in a renewal toxicity test system at 20 C and informed as LC100, LC50 and NOEC for 24 and up till 96 hours of exposure (acute Toxicity Profile -- TPa -- for mercurium). On addition the beneficial effect of zinc against the lethal effect of mercurium is reported. The test with fish were conducted maintaining 10 individuals in 1 L of EPA water (by quadruplicate) in six concentrations of Hg plus controls, while for amphibian, batches of 10 Bufo arenarum embryos at stage 25 (by quadruplicate) were maintained in 40 ml of Holtfreter`s solution in six concentration of Hg + (HgCl) plus controls. The LC100, LC50 and NOEC for fishes expressed in Hg (+) mg/L were: 0.60, 0.25 and 0.10 for 24 hours of exposure. These values increased very slightly at least up till 96 hours of exposure. Therefore, Bufo arenarum seems to be about three times more sensitive than Cnesterodon decemmaculatus to mercurium. By means of simultaneous mercurium-zinc treatment (ZnSO4) the lethal effect of mercurium could be reduced in amphibians up till 100% with 18 mg Zn2+/L, while for the fish the best result obtained was a reduction of about 50% of lethality within the first 96 hours of treatment with 20 mg Zn2+/L. As a whole the results point out the high susceptibility of amphibian embryos to xenobiotics, the beneficial effect of zinc against embryos to xenobiotics, the beneficial effect of zinc against toxicity exerted by Hg and the need of biological test systems for recording the combined effects of substances released to the environment.
- OSTI ID:
- 225183
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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