Occurrence and trophic transfer of nanoparticulate Ag and Ti in the natural aquatic food web of Taihu Lake, China

The wide production and utilization of nanoparticulate Ag and Ti inevitably result in their release into the environment. Thus far, limited information is available regarding to what extent the nanoparticulate Ag and Ti could accumulate in biota and magnify along the food chain in real natural aquatic environments. With the application of single particle inductively coupled plasma mass spectroscopy, we quantitatively demonstrated that both nanoparticulate Ag (18.8-41.0 nm) and Ti (46.6-116 nm) occurred in the water, sediment and aquatic organisms in Taihu Lake, China. Nanoparticulate Ag exhibited greater bioaccumulation potential compared to its other chemical counterparts, and also a greater bioaccumulation factor than nanoparticulate Ti. Sediment served as a main reservoir for nanoparticulate Ag and Ti, and acted as one important exposure source for invertebrates. According to the concentrations of nanoparticulate Ag and Ti in aquatic organisms at different trophic levels, including a variety of invertebrates and fish species, the total and nanoparticulate Ti appeared to be biodiluted in the food web with trophic magnification factors (TMFs) < 1. Conversely, biomagnification of nanoparticulate Ag was found in the fish food web with a TMF of 1.21, while the total Ag was biodiluted. These findings serve as the first line of evidence on the transfer behaviors of nanoparticulate Ag and Ti along the natural aquatic food chain and underline the distinctive bioaccumulation and biomagnification behaviors of nanoparticles as opposed to their other chemical counterparts.