Comparative Assessment of Single and Joint Toxicity of Bulk and Nano Scale Heavy Metals (Al2O3, CuO and SiO2) Using Haematological Parameters as Biomarker in Juvenile African Catfish (Clarias gariepinus)

Global technological advancement has resulted in the gradual replacement of traditional bulk size compounds with nano-sized ones with diverse useful characteristics. This study is focused on the toxicological assessment of three nano-metallic oxides (SiO2, Al2O3 and CuO) in comparison with their equivalent bulk sizes using African Catfish (Clarias gariepinus). The study involved sub-lethal exposures to binary mixtures of selected ratios (1:1; 2:1 and 1:2) of the respective metallic bulk and nano oxides as well as their triple mixture (1:1:1) for 28 days. The catfishes after 28 days were subsequently subjected to haematological tests (Haemoglobin, Packed Cell Volume, Red blood cells, Platelets, Neutrophils, Lymphocytes, Mean cellular volume, Mean Cell haemoglobin, and Mean Cell haemoglobin Concentration). The results of the haematological assessment indicated that most of the nano-sized oxides showed no significant difference (P>0.05) compared to control whereas the bulk sizes either showed no difference or decrease in the count compared to control. In most of the binary mixtures, catfishes exposed to bulk sizes had lower levels of the haematological parameters but there was no overall trend. The introduction of nanoscale metallic oxides into production activities should be with caution since they may have a similar mode of toxicity to the existing bulk sizes.