lakkshmipathiSHEETHAL K. U.,2023-12-222023-12-222022https://krishikosh.egranth.ac.in/handle/1/5810204258Growing production and use of nanoparticles unavoidably results in their accumulation in oceans, rivers, and other bodies of water, posing a threat to the ecosystems health. The gradual introduction of these nanoparticles into the environment has prompted concern about the dynamics and toxic effects of these xenobiotics in various ecosystems, either alone or in combination with other contaminants which could alter their toxicity. This study evaluates the toxicity of joint effects of these different nanoparticles (Titanium dioxide and Silicon dioxide). The acute toxicity of 96 h of LC50 value of TiO2 NPS, SiO2 NPs and Combination of TiO2 +SiO2 NPs for Etroplus suratensis fingerlings was calculated and found to be 160.42 ppm, 128.93 ppm and 61.88 ppm. For sublethal toxicity, the fingerlings were exposed to two sub lethal concentrations i.e., 1/10th and 1/5th of LC50 up to 56 days. Experimental results of accumulation showed that the uptake TiO2 NPs concentration in vital organs were in the order brain> gills> liver> kidney> muscle. Similarly in SiO2 NPs it was liver> gills> brain> muscle> kidney. In combination of TiO2 + SiO2 NPs the highest accumulation was recorded in liver> brain> muscle> gill> kidney. Significant increase in RBC count and WBC was noticed. While, haemoglobin, PCV, MCV, MCH and MCHC showed decreased in fingerlings exposed to NPs. Significant changes was observed enzymatic antioxidants in treatment and control groups. The histology results reveled that TiO2 and SiO2 NPs cause severe damage to morphology of gills, liver, brain, muscle and brain compared that with control group. The study suggested that sublethal concentration of TiO2 and SiO2 NPs altered the hemetological, enzymatic and histological parameters and exerts stress to the fish. Key words: Nanoparticles, TiO2 NPs, SiO2 NPs, Hemetology, Histology, EnzymesEnglishThesis