Phytoremediation of Soil Contaminated with Nickel by Lepidium sativum; Optimization by Response Surface methodology

Phytoremediation is an alternative to traditional chemical and ways of treating polluted soils. The
current study was carried out to investigate the phytoremediation of soil contaminated with nickel
(Ni) by Lepidium sativum. Soil samples from 0 to 10 cm depth were collected. Lepidium sativum was
transplanted in pots containing 5 kg of the collected soils. Central composite design and response
surface methodology were employed in order to illustrate the nature of the response surface in the
experimental design and explain the optimal conditions of the independent variables. Different
concentrations for Ni (1 to 20 mg kg-1) and times for collecting samples (10 to 40 days) were used.
The results showed the amount of Ni removed was ranged from 8.62 mg kg-1 (Ni concentration of 20
mg kg-1 and time for taking samples of 10 days) to 7.066 mg kg-1 (Ni concentration of 10.50 mg kg-1
and time for taking samples of 40days). Additionally, the findings explained that the Lepidium
sativum is an effective accumulator plant for phytoremediation of Ni polluted soils. Optimum
conditions for nickel concentration and time for taking samples were 19.66 mg kg-1 and 39.28 days,
respectively. For the optimum condition, the amount of Ni removed was 10.8095 mg kg-1.