Negative impact of a cadmium concentration considered environmentally safe in Brazil on the cardiac performance of bullfrog tadpoles

A drastic amphibian decline has been observed worldwide, which can be attributed (among other factors) to exposure to pollutants. Considering that cadmium corresponds to the most rapidly increasing trace metal in the environment, the aim of this work was to evaluate whether the exposure (2 and 16 da...

Full description

Saved in:

Bibliographic Details
Published in:	Ecotoxicology and environmental safety Vol. 104; pp. 168 - 174
Main Authors:	Dal-Medico, S.E., Rissoli, R.Z., Gamero, F.U., Victório, J.A., Salla, R.F., Abdalla, F.C., Silva-Zacarin, E.C.M., Carvalho, C.S., Costa, M.J.
Format:	Journal Article
Language:	English
Published:	San Diego, CA Elsevier Inc 01-06-2014 Elsevier
Subjects:	Animal, plant and microbial ecology Animals Applied ecology Biological and medical sciences Bradycardia - chemically induced Brazil Brazilian Environmental Council Resolutions Cadmium - toxicity Cadmium chloride Cardiac performance Ecotoxicology, biological effects of pollution Effects of pollution and side effects of pesticides on vertebrates Fundamental and applied biological sciences. Psychology Heart - drug effects Larva - drug effects Lithobates catesbeianus North American bullfrog tadpoles Rana catesbeiana - physiology Reptilia. Amphibia Water Pollutants, Chemical - toxicity South America Brazil North America America Cardiac performance Brazilian Environmental Council Resolutions Lithobates catesbeianus Cadmium chloride North American bullfrog tadpoles Toxicity Transition metal Compounds Amphibia Salientia Cadmium Chlorides Heavy metal Resolutions Trace element Pollutant Vertebrata Larva Ranidae Circulatory system Brazilian Environmental Council
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	A drastic amphibian decline has been observed worldwide, which can be attributed (among other factors) to exposure to pollutants. Considering that cadmium corresponds to the most rapidly increasing trace metal in the environment, the aim of this work was to evaluate whether the exposure (2 and 16 days) of bullfrog tadpoles to this trace metal, at the concentration currently considered environmentally safe (at 1ppb) in class 1 and 2 waters by the Brazilian Environmental Council, can affect the cardiac performance of these animals. The acute exposure (2 days) of tadpoles to cadmium resulted in a marked bradycardic response, which was correlated with an incomplete cardiac relaxation, without any compensation by improved cardiac twitch force (Fc) or contraction velocity (TPT), nor even by cardiac hypertrophy. Indeed, after 16 days of exposure, the cardiac function of tadpoles became even more depressed due to a marked decrease in Fc, a prolongation of TPT, and also incomplete relaxation (i.e. increases in the ventricle resting tension), without changes in ventricle relative mass. Altogether, the cardiodepressive effects of cadmium (especially after more prolonged exposure periods) impose negative alterations on a tadpole׳s development and also impede adequate homeostatic adjustments to respond appropriately to the exposure to cadmium with increase in energetic demand to counteract the deleterious effects of the xenobiotic. These disturbances can impair tadpoles׳ growth, development and reproduction. It is a fact that allows us to strongly suggest that cadmium concentrations, which are currently considered environmentally safe in Brazil, should be revised. •The acute exposure of tadpoles to cadmium resulted in a marked bradycardia.•This response was not compensated by any improvement in the inotropism.•After 16 days, the impact became more evident, since the contraction force decreased.•Cardiac imbalances can impair tadpoles’ growth, development and reproduction.•The concentration of cadmium considered safe to Brazilian waters should be revised.
ISSN:	0147-6513 1090-2414
DOI:	10.1016/j.ecoenv.2014.03.003