Ecotoxicological effects of TiO2 nanoparticulates and bulk Ti on microalgae Chaetoceros muelleri

Abstract

The substantial use of titanium compounds in different industries has raised concerns about the negative effects on aquatic environments. Therefore it is important to assess their fate in aquatic environments and their uptake by organisms. This study aimed to assess the toxicological effects of nanoparticle TiO 2 and bulk Ti on Chaetoceros muelleri , the microalgae used as a bioindicator of water pollution, in different periods. The compositions of fatty acids, proteins, and carotenoids were selected as ecotoxicological markers in microalgae. The interaction of algal cells with nano-TiO 2 (nTiO 2 ) and bulk Ti was evaluated using Fourier transform infrared (FT-IR) spectroscopy. Physiological and biological results of ecological responses of algae showed that the fatty acid profile, protein, and carotenoid contents decreased in comparison with control samples at different times. Although it was observed that carotenoid and protein contents were significantly different (P < 0.05) at different times, the samples demonstrated no significant difference on days 3 and 6 for bulk Ti and day 3 for nTiO 2 , respectively. The FT-IR measurements indicated a chemical interaction between the nano and bulk compounds with algal cells on their cell surfaces. However, relative to control samples, nTiO 2 and bulk Ti increased polyunsaturated and monounsaturated fatty acids and decreased saturated fatty acids Further studies are required to elucidate the acute effects of nTiO 2 and bulk Ti and their ecotoxicological feedback on the marine environment. • Nano and bulk TiO 2 lead to cytotoxicity and ecotoxicity. • Nano TiO 2 is found more toxic than its bulk due to its properties. • The algae are used in toxicological tests due to their importance for the food web. • These particles inhibition and reduction effects on different algal cellular mechanisms.