Effects of α-Ag2WO4 crystals on photosynthetic efficiency and biomolecule composition of the algae Raphidocelis subcapitata
Abstract: The α-Ag2WO4 (hexagonal rod-shaped) is a multifunctional material with interesting physical and chemical properties, such as good electronic, photocatalytic, anticancer and microbicidal performance. Considering this, its use can contribute to the presence and accumulation of this compound in freshwater ecosystems. Therefore, the present study investigated the effects of α-Ag2WO4 on the freshwater Chlorophyceae Raphidocelis subcapitata, at the level of cell density, chlorophyll a (Chl a), total carbohydrate contents, and photosynthetic activity (maximum quantum yield and oxygen-evolving complex—OEC). The α-Ag2WO4 reduced cell density by ~ 48% already in the first 24 h of exposure at 31.76 μg L−1 (highest concentration). Moreover, at 31.76 μg L−1, we observed a drastic reduction in the maximum quantum yield, and impact in the oxygen evolving complex at 24 h and 48 h. However, our results indicated a possible recovery of the photosynthetic activity in the surviving algal cells at 72 and 96 h. The contents of chlorophyll a (Chl a) and total carbohydrates decreased significantly (Dunnett’s test, p < 0.05) at 4.11, 5.84, 10.55, and 10.67 μg L−1 treatments and increased significantly (Dunnett’s test, p < 0.05) at the highest concentration (31.76 μg L−1), which is possibly a mechanism for the algal cells to optimize the amount of energy to be used in the photosynthetic process and maintaining the integrity of the cell wall. This study contributes to clarifying how α-Ag2WO4 interacts with R. subcapitata¸ showing the toxicity mechanism of photosynthetic activity. This can help predict the fate and effect of these composites by providing a basis for their ecological risk assessment.
Author(s): Abreu, C.B.; Gebara, R.C.; Reis, L.L.; Rocha, G.S.; Alho, L.O.G.; Alvarenga, L.M.; Virtuoso, L.S.; Assis, M.; Mansano, A.S.; Longo, E.; Melão, M.G.G.
Water Air Soil Pollut
Published: 31 March 2022, Volume 233
DOI: https://doi.org/10.1007/s11270-022-05604-x
CDMF
The CDMF, hosted at the Federal University of São Carlos (UFSCar), is one of the Research, Innovation and Dissemination Centers (RIDC) supported by the São Paulo State Research Support Foundation (Fapesp), and also receives investment from the National Council Scientific and Technological Development (CNPq), from the National Institute of Science and Technology of Materials in Nanotechnology (INCTMN).
