Ecological Risk Assessment of Nickel in Soil and the Effects on the Brassica Napus Growth

The presence of nickel ions in soil in high concentrations can cause negative effects on plants, organisms but also on human health. In our study, we considered 4 different concentrations of nickel ions in soil, ranging between 50 mg Ni(II)/kg in soil and 500 mg Ni(II)/kg in soil to estimate the potential ecological risk generated by toxic Ni(II) ions. The study revealed that the risk became considerable when the concentration of nickel ions in the soil exceeds 300 mg/kg. Another objective of this paper was to identify the negative effects of these 4 concentrations of Ni(II) ions on the plant Brassica napus growing, after 8 and 25 days of cultivation in the soil polluted with Ni(II), by evaluating the morphology of the plant and by determining the photosynthetic pigments content. It seems that the presence of nickel ions in soil doesn't cause significant changes in the rape morphology. The results showed that for concentration lower that 50 mg Ni(II)/kg, the synthesis of pigments is not disturbed, while for concentrations up to 100 mg/kg, the content of pigments in plant decrease, the most affected being the synthesis of chlorophyll A.