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Reliable data for bioaccumulation of Ti in fish (BCF) and plants (BSAF) are available, based on a bioaccumulation experiment with TiO2 in rainbow trout (Oncorhynchus mykiss) and monitoring data of elemental Ti in soil and plants, respectively. These results can be used in a read-across approach for UGI, since it is assumed that at equilibrium UGI-derived Ti will have the same fate and distribution as the ambient Ti in the environment. Bioaccumulation of Ti is very low and therefore a significant transfer in the food chain is not expected. Indeed, data on the bioaccumulation of Ti clearly show that a significant bioaccumulation in fish and plants is not likely to occur. Federici et al. (2007) performed accumulation experiments with rainbow trout (Oncorynchus mykiss) in tap water using powder form of TiO2 nanoparticles. After 7 to 14 days of exposure the authors noticed very similar concentrations of Ti in different fish tissues (gills, liver, muscle, brain), i.e. between 11,5 and 21,1 mg Ti/kg dw, irrespective of the added Ti concentrations in the aqueous test medium. Poor adsorption into internal organs and therefore no bioaccumulation of Ti was concluded resulting in BCF values between 19 and 352 L/kg dw. Bioaccumulation data of Ti in plants have been generated by Caille et al. (2005). After 54 days of exposure of different plant species (rape, Brassica napus; cabbage, Brassica oleracea; red fescue, Festuca rubra) the authors noticed very similar low concentrations of Ti in the leaves, i.e. between 0,7 and 2,4 mg Ti/kg dw, resulting in very low biota-to-soil-accumulation factors (BSAF) between 0,0002 and 0,0008 kg/kg.