Assessment of the genotoxic potential of contaminated estuarine sediments in fish peripheral blood: Laboratory versus in situ studies

Abstract

Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine sediments through 28-day laboratory and in situ (field) bioassays. The sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or "comet") assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to sediment contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of sediment contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with sediment contamination levels. While field assays may provide more ecologically relevant data, the multiple environmental variables may produce sufficient background noise to mask the true effects of contamination.

Effects of carcinogenic versus non-carcinogenic AHR-active PAHs and their mixtures: Lessons from ecological relevance

“…This alteration was more obvious in B[b]F and mixture-exposed animals indicates metabolic unbalancing as a major consequence of exposure, even if the occurrence of more severe alterations, such as necrotic foci (accompanied by inflammation) or even apoptosis, although elevated, was more modest. Still, even such an unspecific trait like lipidosis has been link to elevated oxidative stress and risk of acquiring neoplasiarelated disease in experimental animals (see Sánchez-Pérez et al, 2005, andCosta et al, 2011). On their turn, both oxidative stress and DNA damage are linked to cell death, inflammation and neoplasia/preneoplasia (e.g.…”

“…The peroxidative damage of lipids (LPO) was determined by the thiobarbituric acid-reactive species (TBARS) method (Uchiyama and Mihara, 1978, adapted to microplate reader by Costa et al, 2011). The PMS fraction was deproteinized (as previously described) and after centrifugation the supernatant was incubated at 100°C, for 15 min, with thiobarbituric acid (TBA).…”

Inducción de micronúcleos y otras anormalidades nucleares en Astyanax gr. bimaculatus (Pisces: Characidae) expuestas a fenantreno

“…Entre los efectos no controlables de la inmersión pueden citarse las pérdidas por volatilización, absorción y metabolismo (Prosser et al, 2011). A este respecto, en O. mossambicus se evaluó la respuesta a la exposición a PHE usando la vía de administración IP (1 µg/g PV) e inmersión (1 mg/L); aunque ambas exposiciones indujeron la formación de ciertos tipos de aductos de ADN (etapas primarias de procesos mutagénicos) en bilis, la inyección IP indujo los mayores efectos (Wahidulla y Rajamanickam, 2010 efectos mutagénicos de los HAPs se ha evaluado bajo condiciones controladas de laboratorio registrando la presencia de MN y AN, observándose una relación dosis-respuesta (Baršienè et al, 2006;Hoshina et al, 2008;Vanzella et al, 2007 (Costa et al, 2011;Souza y Fontanetti, 2006 (Fig. 3B).…”

Exploring the Potential Interference of Estuarine Sediment Contaminants with the DNA Repair Capacity of Human Hepatoma Cells

“…Detailed data are described in Carreira et al, (2013). for physicochemical parameters and organic and inorganic contamination . Another sample collected in 2007 from a contaminated area of the Sado Estuary was added to the study N 1 , northern area (Costa et al, 2011).…”