Silver Nanoparticles Bioaccumulation by Aquatic Macrophyte Salvinia auriculata

This study evaluated the bioaccumulation capacity of silver nanoparticles (AgNPs) by aquatic macrophyte Salvinia auriculata . These plants were cultivated for 64 days in a nutrient medium containing different silver nanoparticles (1.0, 5.0, and 10.0 mg L −1 ). Total concentrations of silver were monitored in the culture medium during the experiments to evaluate removal. Determination of total silver in plant root and leaf samples was performed to evaluate the effect of different concentrations on bioaccumulation. Macro and micronutrient levels in leaves and roots and photosynthetic pigments in the leaves were quantified before and after 64 days of cultivation. In the culture medium, the behavior of S. auriculata in presence of AgNPs was monitored by the following parameters: tolerance index, biomass production, silver removal, uptake index, bioconcentration factor, and translocation factor. S. auriculata could survive in high concentrations of AgNP (5.0 and 10.0 mg L −1 ) and was able to absorb silver. At the AgNPs concentration of 1.0 mg L −1 occurred higher silver removal (88%) by the plant, besides a higher biomass growth. Decreased silver uptake and S. auriculata biomass growth in the 5.0 and 10.0 mg L −1 samples may be associated not only with the presence of this metal but also its interference with nutrient uptake, especially the phosphorus. This study shows that aquatic macrophyte can bioaccumulate silver nanoparticles. These nanoparticles are present in several commercial products, such as footwear socks, in the manufacture of healing bandages, inside refrigerators, and food storage containers to retard spoilage, among other applications.