Assessment of biotic and abiotic behaviour of engineered SiO2 nanoparticles for predicting its environmental providence

Silica oxide (SiO2) nanoparticles and their CTAB, CTAC, CPB and CPC modified counterparts are among the most commonly used nanoparticles. However, their potential environmental toxicity and fate in the environment are not known. To assess the overall risk possessed by these nanoparticles, the biotic and abiotic effects of these emergent pollutants have been evaluated. In this study, four different in vitro toxicity assessment methods have been used to assess the toxicity of SiO2 nanoparticles. The seed germination of V. radiata reduced to 53.33, 43.33, 40 and 33.33 for CTAB, CTAC, CPB and CPC coated Silica nanoparticles from 66.66 for control. Also the reduction in chlorophyll content (17–19%), HE, RE and RC values; MI and RMI values in Allium cepa chromosomal aberrations assay showed the toxic nature of the nanoparticles. The final fate of the particles in the environment has been assessed through the sorption and degradation behavior in the nature-identical laboratorial conditions. The nanoparticles showed a significant aggregation beyond 100 mM salt concentrations. A very high concentration i.e. about 40–55% of the nanoparticles was found to be sorbed by the soil particles and <1.2% concentration was found to be photodegradable. These results are meaningful for improved understanding and prediction of the behavior and fate of SiO2 nanoparticles in the environment.