Effects of copper and cadmium spiked-sediments on embryonic development of Japanese medaka (Oryzias latipes)

Abstract

Because of their high capacity to accumulate contaminants such as persistent organic pollutants and heavy metals, aquatic sediments are considered as a long-term source of contamination for aquatic organisms. In compliance with the increasing interest both for sediment quality evaluation and the use of fish early life stage (ELS) toxicity assays, we proposed an embryo-larval test to evaluate embryotoxicity and genotoxicity of sediment-bound contaminants. Pre-blastula stage medaka (Oryzias latipes) embryos were exposed by static sediment contact to two model heavy metals (cadmium and copper) at environmental concentrations during the whole 10-day embryonic development. Lethal and sub-lethal effects were recorded in both embryos and larvae for 20 days post fertilisation (dpf) using several global toxicity and phenotypic endpoints. The comet assay was also performed on medaka prolarvae to evaluate genotoxic effects of the tested chemicals. Environmental concentrations of cadmium (Cd) and copper (Cu) did not affect embryo and larval survival. However, both heavy metals significantly induced morphological abnormalities, particularly spinal and cardiovascular deformities. Cd but not Cu induced tachycardia. Both heavy metals induced a significant increase in DNA damage at all tested concentrations. Resulting LOEC values for Cd and Cu corresponded to 1.9 and 8.5 μg/g d.w. sediment, respectively. Although metal bioavailability is probably lower for naturally contaminated sediments, the relatively low toxicity thresholds for both Cd and Cu raise the question of possible risk for fish embryos developing in direct contact to sediments. This study demonstrates the applicability, sensitivity and relevance of the Japanese medaka embryo-larval assay (MELA) to evaluate sediment hazardous potency at environmental concentrations of heavy metals.

Spinal deformities in a wild line of Poecilia wingei bred in captivity: report of cases and review of the literature

“…Several chemical/physical water parameters are known to be responsible for spinal malformations in fish [19] , including pH and heat shock [12,20] , low dissolved oxygen [21] , herbicides, organophosphate and organochlorine pesticides [22] , heavy metals [11,[23][24][25][26][27][28] and other pollutants [11,[29][30][31][32] . These potential causes do not seem to be related to our cases since the water of the farm was previously filtered in a reverse osmotic system in order to block heavy metals and other potential dangerous chemical agents, and then added with specific salts and water conditioner (Sera Aquatan 襆 ).…”

Application of a multidisciplinary and integrative weight-of-evidence approach to a 1-year monitoring survey of the Seine River

“…The procedure was similar for the two assays and followed previously published protocols (Vicquelin et al 2011;Barjhoux et al 2012;Barhoumi et al 2016). In summary, exposure was performed at 26 ± 0.3°C and stopped at the first hatching peak in one of the test conditions (10-11 dpf).…”

“…Hatchlings and unhatched embryos were transferred to clean water or ERS, respectively, for three additional days. Viability, time to hatch, hatching success, body and head length, and developmental abnormalities were recorded in embryos and larvae according to Barjhoux et al (2012).…”

Molecular and phenotypic responses of Japanese medaka (Oryzias latipes) early life stages to environmental concentrations of cadmium in sediment

“…In addition to its widely recognized carcinogenicity and mutagenicity, Cd was also reported as an important teratogenic and embryotoxic chemical in several fish species (Hallare et al 2005;Brinkman and Hansen, 2007;Benaduce et al 2008;Cao et al 2009; Barjhoux et al 2012) and several studies already investigated gene expression modulation…”