Assessment of bioaccumulation and toxic effects of cobalt (II) aluminate nanoparticles for hygienic safety purposes

Hygienic safety plays an important role in preventing health harm under chemical exposures. Hygienic regulation of levels of existing and new substances in environmental objects is the core element here carried out within experimental research aimed at establishing their toxic properties. Cobalt (II) aluminate nanoparticles (CoAl2O4 NPs) are a typical example of a new material with presumably higher toxic potential upon oral exposure as opposed to micro-sized particles (MPs). Given that, the development of safety standards requires identifying features of the negative impact of CoAl2O4 NPs, which are different from MPs upon oral exposure. The study was performed on Wistar rats orally exposed to NPs and MPs for 20 days at the total dose of 10,550 mg/kg of body weight. NPs have chemical composition similar to MPs, smaller size (87.11 times) and larger specific surface area (1.74 times). NPs have a more pronounced ability to bioaccumulate in the heart, lungs, liver and kidneys as compared to MPs (up to 7.54 times). Exposure to NPs resulted in more pronounced (up to 3.60 times) changes in blood indicators associated with developing redox imbalance, cytotoxic effect, liver, pancreas and kidney dysfunction, inflammatory process, and thrombocytopenia. NPs caused hemorrhagic infarcts and pulmonary edema not established upon MPs exposures. The calculated value of the tentatively permissible exposure level (TPEL) was 0.02 mg/dm3 for these NPs content in drinking water, which is 10 times lower than the same value for MPs. Thus, CoAl2O4 NPs upon oral exposure for 20 days at the total dose of 10,550 mg/kg of body weight have more marked bioaccumulation relative to MPs, which causes more pronounced negative effects identified by changes in blood indicators and developing pathomorphological changes. The study findings allow increasing accuracy and objectivity when developing safety standards for CoAl2O4 levels in food products and drinking water to ensure greater hygienic safety of the population.