Diminishing bioavailability and toxicity of P25 TiO2 NPs during continuous exposure to marine algae Chlorella sp
| Autor: | Amitava Mukherjee, Vignesh Thiagarajan, Pavani M, S. Archanaa, N. Chandrasekaran, Suraishkumar G K, R. Seenivasan |
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| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Radical 0208 environmental biotechnology 02 engineering and technology 010501 environmental sciences medicine.disease_cause 01 natural sciences chemistry.chemical_compound Algae medicine Environmental Chemistry 0105 earth and related environmental sciences Aqueous solution biology Chemistry Superoxide Public Health Environmental and Occupational Health General Medicine General Chemistry Sedimentation biology.organism_classification Pollution 020801 environmental engineering Bioavailability Environmental chemistry Toxicity Oxidative stress |
| Zdroj: | Chemosphere. 233:363-372 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2019.05.270 |
| Popis: | Titanium dioxide nanoparticles (TiO2 NPs) find applications in our day-to-day life because of unique physicochemical properties. Their release into the aquatic environment poses a possible risk to the organisms. However, the continuing exposure of NPs might reduce their bioavailability to marine organisms owing to aggregation and sedimentation in the aqueous systems thus significantly reducing their toxic impact. In this regard, the present study investigates the effect of continuous exposure of TiO2 NPs to marine microalgae Chlorella sp. under UV-A irradiation through “tanks in series” mode of experiments. In a three-cycle experiment, concentration of TiO2 NPs in the first cycle was fixed at 62.6 μM, and the interacted nanoparticles was subsequently exposed to fresh batches of algae in the next two cycles. After the interaction, the NPs underwent severe aggregation (mean hydrodynamic diameter 3000 ± 18.2 nm after cycle I) leading to gravitational settling in the medium and thus decreased bioavailability. The aggregation can be attributed to interactions between the particles themselves (homo-aggregation) further aggravated by the presence of the algal cells (hetero-aggregation). Cellular viability after cycle I was found to be only 24.2 ± 2.5%, and it was enhanced to 96.5 ± 2.8% after the cycle III in the course of continuous exposure. The results were validated with estimation of oxidative stress markers such as intracellular ROS (total ROS, superoxide and hydroxyl radicals) and LPO after each cycle of exposure. The continuing decrease in the EPS across the cycles further confirmed the diminishing toxicity of the NPs. |
| Databáze: | OpenAIRE |
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