Using an innovative approach based on nanotechnology, the biocide DCOIT was encapsulated in silica nanoparticles (SiNC) in order to reduce its environmental impact and to improve its antifouling efficacy. However, studies on its bioaccumulation and trophic transference are required, as well as those regarding its toxicity. The present study aims to assess the bioaccumulation and trophic transferability of both free DCOIT and its encapsulated form (SiNC-DCOIT) by feeding bivalves with contaminated algae. Firstly, an experiment will be set up to identify whether microalgae and bivalves can internalize SiNC and bioaccumulate DCOIT. In such experiment, algae and bivalves will be exposed (separately) to a sublethal concentration of DCOIT and SiNC (labeled with a chromophore). Then, by fluorescence microscopy, the internalization of SiNC will be verified. To confirm bioaccumulation, we will develop and refine methods of extraction and quantification of DCOIT in biological matrices (algae and bivalves) and water. Once the bioaccumulation is confirmed and the quantification protocols have already been developed, a second experiment will be set up to verify the trophic transfer of DCOIT and SiNC-DCOIT in bivalves. For this experiment the mussel Mytilus galloprovincialis will be fed with the microalgae Tetraselmis chuii contaminated for 72 h, comprising 4 treatments, algae contaminated with DCOIT or SiNC-DCOIT or SiNC and algae not contaminated. After the feeding and exposure period, the concentrations of DCOIT and SiNC-DCOIT in organisms and water will be quantified to determine if there is trophic transfer.
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