This study was conducted to evaluate the effect of metals on wheat and bean species. The method uses seed germination and early seedling growth of these plants in the presence of various levels (10, 50, 100, 250, 500, 750 and 1000 mg/L) of Cadmium (Cd), Iron (Fe) and Zinc (Zn). The inhibition caused by these metals was depending on the concentration used, the metal itself and the plant species. The species had reduced seed germination, root and shoot lengths, tolerance index and percentphyto-toxicity with increasing concentrations of metals. Cadmium was determined to be the most inhibitory metal on these parameters. This metal affected significantly the germination, root and shoot length of the species tested, as well as the tolerance index and percentphytotoxicity starting from 50 mg Cd/l. Under the Iron stress, in general, the inhibition of germination and root length of wheat was reduced from 500 mg Fe/l. The results showed also that the inhibitory effect of increase of Zn levels was seen in root, shoot and tolerance indices. The findings also revealed that the metal toxicity was as follow: Cd > Fe > Zn. Regarding species, the results showed that bean seemed to be more tolerant to the increase of the three metals than wheat.
In this work three heavy metals: cadmium (as CdSO4), cobalt (as CoCl2) and zinc (as ZnSO4), were used to determine and compare their toxicity towards two subspecies of barley (Hordeum vulgare subsp. vulgare L. and Hordeum vulgare subsp. distichum L.), focusing on seeds germination, seedlings growth, and cytological parameters. The results indicate that the effect of these heavy metals depends on the metal kind, the metal concentrations and the plant subspecies. Generally, in the case of H. vulgare, the heavy metal salts understudy did not influence significantly seed germination and seedling growth parameters. However, these metal salts influence significantly these parameters for H. distichum. The cytological test showed significant decrease (p < 0.05) in the mitotic index among the increase of the heavy metal concentrations when evaluated with the control for H. vulgare and H. distichum. Consequently, H. vulgare seemed to be more tolerant of the increase of the three heavy metals concentrations than H. distichum.
The concentrations of metals were determined in soil samples collected in Ait Ammar (Oued Zem, Morocco). The mean Cd, Cr, Cu, Fe, Pb and Zn contents in the mining topsoil samples were: 2.12, 135, 34.9, 214, 9.13 and 90.8 mg kg−1, respectively. Human health risks developed from metal ingestion, dermal absorption and inhalation of soils were also evaluated. For non-carcinogenic risks, united hazard index (HI) values for children surpassed the safe level (HI=1) for Cr (13.1). Values for HI in adults (1.74) also surpassed the safe level for Cr. The HI values for Pb and Cd for children were 0.69 and 0.68, respectively. Cancer risk due to Cr surpassed the tolerable range (1E-06 to1E-04) for children (1.05E-03) and for adults (1.42E-04). Cancer risks due to Pb and Cd were within acceptable ranges for both children and adults. Furthermore, oral ingestion of soil particles contributed more highly to both carcinogenic and non-carcinogenic risk from Cr than either dermal absorption or inhalation in both children and adults.