226Ra, 40K and 7Be activity concentrations in plants in the environment of Kaiga,India

Leaves, stem and bark samples from several plant species were collected from tropical forest of Kaiga, in the west coast of India where two nuclear power reactors of 220 MW each have just been commissioned and another two are under construction, and analysed for their (226)Ra, (40)K and (7)Be concentrations. The activities of (226)Ra and (40)K in plants were found to vary in the range BDL-13.2 and 12.0-797.3 Bq kg(-1), respectively. Plants show significant (7)Be activity in leaves, the activity varies in 72.5-1,060.8 Bq kg(-1). Stem and bark of plants show higher levels of (226)Ra and (40)K when compared to leaves. Soil-to-plant transfer factor for (226)Ra and (40)K were found to vary in the range BDL-0.37 and 0.09-5.61, respectively for different plants. The concentration of (226)Ra and (40)K in leaves depends on the age of the leaves.     

Thermal co-reduction approach to vary size of silver nanoparticle: its microbial and cellular toxicology

In recent years, silver nanoparticles (AgNPs) have attracted considerable interest in the field of food, agriculture and pharmaceuticals mainly due to its antibacterial activity. AgNPs have also been reported to possess toxic behavior. The toxicological behavior of nanomaterials largely depends on its size and shape which ultimately depend on synthetic protocol. A systematic and detailed analysis for size variation of AgNP by thermal co-reduction approach and its efficacy toward microbial and cellular toxicological behavior is presented here. With the focus to explore the size-dependent toxicological variation, two different-sized NPs have been synthesized, i.e., 60 nm (Ag60) and 85 nm (Ag85). A detailed microbial toxicological evaluation has been performed by analyzing minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), diameter of inhibition zone (DIZ), growth kinetics (GrK), and death kinetics (DeK). Comparative cytotoxicological behavior was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It has been concluded by this study that the size of AgNPs can be varied, by varying the concentration of reactants and temperature called as “thermal co-reduction” approach, which is one of the suitable approaches to meet the same. Also, the smaller AgNP has shown more microbial and cellular toxicity.