Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax

Abstract

Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms.Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

Sub-lethal effects of waterborne copper in early developmental stages of rainbow trout (Oncorhynchus mykiss)

“…However, at 24 h exposure, differences were only observed on fish exposed to the strongest Cu concentration (1 mg/L). Canalejo et al (2016) also observed that micronuclei frequency was even more important for fish exposed to Cu than those exposed to As or Pb at the same concentrations. Environmental concentrations of Cu (3.2 to 128 µg/L) induced DNA strand breaks in a concentration-dependent manner in blood cells of mature male stickleback after exposure for 4-days (Santos et al, 2010).…”

“…Oss et al (2013) observed an increase of micronuclei levels after 30-days exposure to environmental concentrations of Cu (0, 25, 50 µg/L) on juvenile fat snook (Centropomus parallelus), and these differences did not change after 30-days of recovery. In one study, a significant increase of micronuclei levels was also observed on European seabass (Dicentrarchus labrax) exposed to Cu (0.01-1 mg/L) for 96 h (Canalejo et al, 2016). However, at 24 h exposure, differences were only observed on fish exposed to the strongest Cu concentration (1 mg/L).…”

“…The comet assay did not reveal any significant induction of DNA damage promoted by Cu exposure. However, several studies have reported DNA damage upon exposure to Cu or other metals (Barjhoux et al, 2012;Bopp et al, 2008;Canalejo et al, 2016;Oss et al, 2013;Santos et al, 2010). Barjhoux et al (2012) demonstrated the genotoxic potential of Cu and Cd on Japanese medaka larvae after embryonic exposure to environmental sediments from contaminated sites of the Lot-Garonne-Gironde continuum.…”

Genotoxic Changes in Herring from the Southern Baltic Sea

“…Nowadays, when the occurrence of these compounds is in the wider perspective taking their variety into account, it is not easy to identify one substance responsible for a given type of harmful effect or verify one factor causing the changes occurring in marine organisms. The changes in cells can be caused by ionizing radiation, heavy metals, petrochemical products, pharmaceuticals and pesticides [3][4][5][6][7][8][9][10][11][12][13]. In order to undertake evidence-based preventive and remedial actions it is important to verify and characterize the ecological risks generated by the presence of hazardous substances in the marine environment.…”