title: 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.
authors.affiliation: Univ. Bordeaux, EPOC/LPTC, UMR 5805, F-33400 Talence, France.
authors.forename: Iris
authors.initials: I
authors.lastname: Barjhoux
authors.affiliation: Univ. Bordeaux, EPOC/EA, UMR 5805, F-33400 Talence, France.
authors.forename: Magalie
authors.initials: M
authors.lastname: Baudrimont
authors.affiliation: Univ. Bordeaux, EPOC/LPTC, UMR 5805, F-33400 Talence, France.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Morin
authors.affiliation: Univ. Bordeaux, EPOC/LPTC, UMR 5805, F-33400 Talence, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Landi
authors.affiliation: Univ. Bordeaux, EPOC/EA, UMR 5805, F-33400 Talence, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Gonzalez
authors.affiliation: Univ. Bordeaux, EPOC/LPTC, UMR 5805, F-33400 Talence, France. Electronic address: jerome.cachot@u-bordeaux1.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cachot
mesh_terms: D000818:Animals; D001681:Biological Assay; D002104:Cadmium / Q000633:toxicity*; D020552:Comet Assay; D003300:Copper / Q000633:toxicity*; D004249:DNA Damage; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D019015:Geologic Sediments / Q000737:chemistry; D007814:Larva / Q000187:drug effects; D008297:Male; D009153:Mutagens / Q000633:toxicity; D009990:Oryzias / Q000196:embryology*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009153:Mutagens; D014874:Water Pollutants, Chemical; D002104:Cadmium; D003300:Copper