The increasing production of nanoparticles (NPs) will lead to their release into the aquatic environment, where they could modify the bioavailability/bioconcentration and consequent biological impact of other contaminants. Interactive effects of n-TiO2, one of the most widespread NP type, and Cd2+, a common heavy metal pollutant, have been described in freshwater species, whereas no information is available in marine organisms. In this work, the effects of co-exposure to n-TiO2 and Cd2+ were investigated in the marine bivalve Mytilus galloprovincialis. Experimental conditions (100μg/L, 96h), were chosen in order to induce early but measurable stress responses (biomarkers) without toxicity. Several biomarkers, from molecular to tissue level, were measured in hemolymph and digestive gland; the effects on embryo development were also evaluated. In hemolymph, Cd2+ abolished the increase in immune parameters induced by n-TiO2 (NO production and lysozyme activity). In the digestive gland, distinct interactive effects of n-TiO2 and Cd2+ were observed on different lysosomal biomarkers (lysosomal membrane stability, lipid accumulation and lysosome/cytoplasm volume ratio) and transcription of the immune genes lysozyme and toll-like receptor (TLR). However, n-TiO2 did not affect specific metal-induced responses (metallothionein induction) and tissue metal accumulation. Cd2+ alone, but not in combination with n-TiO2, affected embryo development. The interactive effects observed on different biomarkers were not apparently due to differences in bioavailability/bioaccumulation of Cd2+ in the presence of n-TiO2 agglomerates; these effects may result from interactions of either contaminant with both common and distinct targets/mechanisms of action at different levels of biological organization. Overall, the results indicate that co-exposure to n-TiO2 and Cd2+ did not result in increased adverse effects in M. galloprovincialis. These data underline the need for further knowledge on the potential interactions of NPs with existing contaminants in marine organisms.
|Titolo:||Co-exposure to n-TiO2 and Cd2+ results in interactive effects on biomarker responses but not in increased toxicity in the marine bivalve M. Galloprovincialis|
|Data di pubblicazione:||2014|
|Appare nelle tipologie:||2.1 Articolo su rivista |
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|2014_Balbi et al.SciTotEnv.pdf||Documento in Post-print||Accesso chiuso-personale||Riservato|