Allium Root-micronucleus (Allium-MCN) test on the genotoxicity of soil samples contaminated with heavy metals

Allium Root-MCN bioassay was used to determine the cytotoxicity of 5 soil samples. Two types of soils were studied: contaminated one collected near of copper-smelters (the Middle Urals) and Ni-enriched soil from an area of a natural geochemical anomaly (the Polar Urals). We measured potentially mobile forms of metals in soils and water-soluble concentrations of metals in soils with standard methods. Allium roots were exposed in aqueous soil extracts for 30 hours with a recovery duration for 20 and 44 hours. We found an increase of frequencies of total nuclear anomalies in meristematic cells as compared to control samples. The most frequent types of anomalies in all studied samples were extrusions. Influence of high Ni concentrations leads to decrease of roots growth that was observed after recovery time also and increasing of number of micronucleus. The frequency of micronuclei in cells of root tips increased up to 6.5 fold as compared to control samples. The total number of anomalies and contribution of extrusions among them was higher for contaminated soils with prevalence of Cu. After the second recovery time point of 44 hours the number of anomalies increased dramatically, that allow recommend such period for similar experiments. In conclusion, high concentrations of Ni lead to decrease of roots growth that was observed after recovery time also and increasing of number of micronuclei. © IDOSI Publications, 2012