Studying the effect of heavy metals and the preservative at the cellular level using Allium Cepa. L as a bioindicator

Environmental pollution is a matter of concern for living organisms and the environment, so bioindicators have been used to detect the harmful effect of chemicals. In this study, Allium cepa L. plant was used as a bioindicator to detect the toxicity of heavy metals that causes chromosomal abnormalities in the growing points of meristematic cells of onion plants; the metals were: cadmium, zinc, copper, lead, polluted water and the preservative (sodium benzoate). It has been observed that heavy metals and the preservative cause various types of chromosomal abnormalities, which include chromosomal dispersal, sticky chromosome, ring chromosome, chromosomal fragments, lagging chromosome, multipolar chromosome, and c-mitosis, star chromosome, chromosome bridge, and centromere break. Depending on the mitotic index, its decrease is an indication of a decline in the division average, indicating a disorder in the cell division pathway, from the most effective to the least effective: sodium benzoate > copper > lead > polluted water > zinc > cadmium. The study aimed to estimate the percentage of damage in living cells resulting from the effect of heavy metals and the preservative used in food products that are directly related to human life