Effect of TiO(2) Nanoparticle on Bioaccumulation of ndl-PCBs in Mediterranean Mussels (Mitilus galloprovincialis)

SIMPLE SUMMARY: The interaction of nanomaterials with pollutants in the marine environment might alter bioavailability, as well as toxicity, of both nanomaterials and pollutants, representing a risk, not only for marine organisms, but also for consumers through the marine food chain. The aim of this research was to study whether titanium dioxide nanoparticles affect bioaccumulation and toxicity of pollutants, such as non-dioxin-like polychlorinated biphenyls in edible mussels harvested in a controlled contaminated environment. The results highlighted that titanium dioxide nanoparticles do not affect non-dioxin-like polychlorinated biphenyls’ accumulation in mussels, as their concentration was comparable with or without nanoparticles. Titanium dioxides nanoparticles in combination with non-dioxin-like polychlorinated biphenyls amplified the toxic effect on mussels compared to the exposure of non-dioxin-like polychlorinated biphenyls. Finally, mussels were submitted to a seven-day depuration process to evaluate the elimination of accumulated chemicals. Most titanium dioxide nanoparticles were eliminated after depuration, and their presence had a synergistic effect on non-dioxin-like polychlorinated biphenyls, which were eliminated in a greater quantity compared to mussels exposed only to non-dioxin-like polychlorinated biphenyls. In any case, consumers might be exposed to TiO(2)NPs and ndl-PCBs (both concurrently and separately) if edible mussels, harvested in a contaminated environment, are consumed without a proper depuration process. ABSTRACT: The interaction of nanomaterials with pollutants in the marine environment might alter bioavailability, as well as toxicity, of both nanomaterials and pollutants, representing a risk, not only for marine organisms, but also for consumers through the marine food chain.The aim of this study was to evaluate the effect of titanium dioxide nanoparticles (TiO(2)NPs) in terms of bioaccumulation and toxicity on Mediterranean mussels (Mytilus galloprovincialis) exposed to six-indicator non-dioxin-like polychlorinated biphenyls (ndl-PCBs). Mussels were exposed to ndl-PCBs (20 µg/mL) (groups 3–4) or to a combination of ndl-PCBs (20 µg/mL) and TiO(2)NPs (100 µg/mL) (groups 5–6) for four consecutive days. TiO(2)NPs was detected in groups 5–6 (3247 ± 567 and 1620 ± 223 µg/kg respectively), but their presence did not affect ndl-PCBs bioaccumulation in mussels. In fact, in groups 3–4, the concentration of ndl-PCBs (ranging from 3818.4 ± 166.0–10,176 ± 664.3 µg/kg and 2712.7 ± 36.1–9498.0 ± 794.1 µg/kg respectively) was not statistically different from that of groups 5–6 (3048.6 ± 24.0–14,635.9 ± 1029.3 and 5726.0 ± 571.0–9931.2 ± 700.3 µg/kg respectively). Histological analyses showed alterations to the structure of the gill tissue with respect to the control groups, with more severe and diffuse dilatation of the central hemolymphatic vessels of the gill lamellae in groups 5–6 (treated with TiO(2)NPs and ndl-PCBs concurrently) compared to groups 3–4 (ndl-PCBs only). Finally, in mussels submitted to a seven-day depuration process, most TiO(2)NPs were eliminated, and NPs had a synergistic effect on ndl-PCBs elimination; as a matter of fact, in groups 5–6, the percentage of concentration was statically inferior to the one observed in groups 3–4. In any case, consumers might be exposed to TiO(2)NPs and ndl-PCBs (both concurrently and separately) if edible mussels, harvested in a contaminated environment, are consumed without a proper depuration process.