Cytotoxic and genotoxic effects of macro- and nano-form of heavy metals in Pisum sativum L. grown in soil

Improper dumps are one of the most common indicators of accumulated harm and are a source of a wide range of pollutants entering the environment. The waste of packaging materials, household chemicals, agrochemicals, used industrial catalysts, ash from thermal waste disposal, and other contaminants have been identified as sources of their introduction into soils from dumps. The accelerated applications of nano-forms of metals are one of the emerging concerns. Like other contaminants, the soil is the main sink for nanoparticles (NPs). Undoubtedly, in the last decade, metal NPs have been recognized for their numerous roles in research and development but due to their increasing amount in the environment, these emerging issues cannot be ignored. Therefore, with this background, the current work was proposed, in which, Pisum sativum L. was exposed to nano-disperse (30-50 nm) and macro-disperse (3-5 μm) forms of metal oxide viz., Cu, Zn, Cr, Mn, Cd, Ti, Ni, and Pb at the doses of 3, 30, and 90 background contamination (in mg/kg). After 3-4 days of exposure, the emerged roots were harvested, cleaned with distilled water, and fixed in Clark’s fluid (aceto-alcohol) for further analyses. For microscopic observations, slides were prepared using the squash technique. In this work, the mitotic index and frequency of chromosomal aberrations were recorded to depict the extent of cytotoxic and genotoxic effects, respectively. The experimental outcomes revealed that the maximal genotoxicity was found in all soil samples at the level of 90 background contamination, regardless of the macro- or nano-state of the metals. Besides, the commonly observed chromosomal aberrations were bridges and fragments. Also, cell ruptures at the metaphase stage, forming a metaphase plate was found but rarely. Thus, the current observation depicted the cytotoxicity and genotoxicity of different nano- and macro-disperse forms of metals, however further studies are needed to explore the responsible mechanisms for these toxicological vulnerabilities.  

This study was supported by Russian Science Foundation project no. 21-77-20089.