Zhu et al. were the first to provide evidence that TiO₂ NPs (21 nm) can transfer from daphnia to zebrafish by dietary exposure. Hence, dietary intake could be a major route of exposure to NPs for high trophic level aquatic organisms. Ecological research should therefore focus, not only on the concentration of NPs in the environment, but also on its bioconcentration, bioaccumulation and biomagnification. In addition it has been shown that TiO₂ NPs can increase accumulation of other environmental toxicants: enhanced accumulation of cadmium (Cd) and arsenic (As) was found in carp in the presence of TiO₂ NPs. The strong adsorption capacity for Cd and As was explained by the large specific surface area and strong electrostatic attraction of TiO₂ NPs that contribute to facilitated transport into different organs.

Lithopone was discovered in the 1870s by DuPont. It was manufactured by Krebs Pigments and Chemical Company and other companies.^[2] The material came in different seals, which varied in the content of zinc sulfide. Gold seal and Bronze seals contain 40-50% zinc sulfide, offering more hiding power and strength.^[3] Although its popularity peaked around 1920, approximately 223,352 tons were produced in 1990. It is mainly used in paints, putty, and in plastics.^[1]