Internal distribution of uranium and associated genotoxic damages in the chronically exposed bivalve Corbicula fluminea
Résumé
Uranium (U) internal distribution and involved effects in the bivalve Corbicula fluminea have been studied after direct chronic exposure (90 d, 10 μg.L-1). U distribution was assessed at the subcellular level (Metal Rich Granules -MRG-, pellets and cytosol fractions) in two main organs of the bivalve (gills and visceral mass). Micro-localisation was investigated by TEM-EDX analysis in the gills epithelium. DNA damage in gill and hemolymph samples was measured by the Comet assay. The 90-d exposure period led to a significant increase of U concentration in gills over time (×5) and a large U quantity in subcellular granules in gills. Finally, a significant increase (×2) in DNA damage was noted in exposed gills and haemocytes. This study shows that the accumulation levels and consequently the potential toxicity cannot be successfully predicted only on the basis of concentration in water or in tissues and subcellular fractions after chronic exposure. © 2011 Elsevier Ltd.
Mots clés
Bivalve
Chronic exposure
Comet assays
Corbicula fluminea
Cytosols
DNA damages
Exposure period
Genotoxic damage
Micro-localisation
Sub-cellular
Subcellular fractions
TEM-EDX
Granulation
Tissue
Uranium
uranium
accumulation
bivalve
damage
freshwater ecosystem
genotoxicity
pollution exposure
transmission electron microscopy
vertical distribution
animal tissue
article
blood cell
DNA damage
gill
long term exposure
nonhuman
tissue distribution
viscera
Animals
Comet Assay
Corbicula
DNA Damage
Environmental Exposure
Gills
Hemolymph
Microscopy
Electron
Scanning Transmission
Radiation Monitoring
Water Pollutants
Radioactive
Bivalvia