The Effect of Potassium Fertilizers on Lead and Cadmium Phytoremediation by Lavender (Lavendula Officnalis) in a Polluted Soil

The use of medicinal plants for remediation of heavy metals contaminated soils is an economical, cheap and effective strategy. The widespread transfer of natural materials and pollutants to different parts of the environment (soil, water and atmosphere) has imposed great pressure on the self-purification ability of the soil. Accumulation of pollutants is a concern regarding both humans and ecosystems. Among pollutants, heavy metals are particularly important because they are not decomposable and also have harmful physiological effects on organisms even at low concentrations. lead and cadmium are heavy metals which enter water, soil, plants and ultimately the human and animals food chain from variouse sources and can cause serious damage. Therefore doing research works in order to refine the elements of the environment is essential. Different methods for refining contaminated soils are mostly very expensive and costly. It seems using less costly methods for removing contaminated soil contamination can help to refine and optimize the use of these lands. One of the new and low cost methods for refining contaminated soils is using plants (Phytoremediation). Phytoremediation is an emerging technology that utilizes plants and microorganisms found in rhizosphere to delete, modify or limit the toxic chemicals in soil, sediments, groundwater, surface water and even the atmosphere is used. The aim of research is investigation effects of different sources of potassium on the concentration of cadmium ,lead, and Phytoremediation promotion by lavender (Lavendula Officnalis L.).The experiment conducted in a polluted soil with Cadmium and lead, in the university agricultural research Institute on basis of randomized complete block design, with 3 replication and 5 treatments including CdCl2 in two levels 0 , 15 mg per kg soil, Pb)No3)2 in two levels 0 , 100 mg per kg soil, potassium sulfate , potassium nitrate and potassium chloride each at three levels of 0, 55 , 110 mg K2O per kilogram of soil.Analysis of variance showed that potassium fertilizers have significant effect on concentration cadmium and lead in shoot and root. Also, according to results, maximum amount cadmium concentration in shoot (2.1mg.kg-1.D.M) and root (1.63mg.kg-1.D.M) was obtained by application of 110 mg per kg of soil as KCl. The maximum amount lead concentration in root(9.1mg.kg-1.D.M) in levels of 110 mg per kg in each of treatments potassium sulfate and potassium chloride was obtained. This results indicate the high capability of lavender for heavy metals uptake from contaminated soils. Further accumulation of cadmium(Cd) and lead(Pb) in the lavender roots than shoots of the findings was of this study.