LOGO REMEDIATION OF HEAVY METALS-CONTAMINATED SOIL AHMED K. SALAMA, KHALED A. OSMAN AND NEAMA A. GUDA Faculty of Science, Majmaah University and Alexandria University This report is based upon work supported by the Basic Science Research Unit, Scientific Research Deanship, Majmaah University 2015 ABSTRACT: The currently used techniques for soil remediation such as landfilling or metal extraction using toxic agents as well as the use of metal- chelating bio-surfactant need to be replaced by green technology solution. Therefore, the research was designated to study the ability of plants to bio-accumulate, translocate and remove some metals such as copper, zinc, lead and cadmium from contaminated soil. The herbal plant ryegrass, Lolium multiflorum was investigated as a bio- accumulator plant for these metals. The translocation of these heavy metals in ryegrass was compared considering root to shoot transport and redistribution of metals in the root and shoot system. The trace metal contents from root and shoot parts were determined using atomic absorption spectrometer. The results showed that the percent of copper, zinc, lead and cadmium transferred to ryegrass plant were 96.01, 84.51, 51.39, and 74.57%, respectively, while those remained in the soil were 3.81, 14.42, and % following 60 days of treatment. The soil-plant transfer index in root and shoot system of ryegrass was found to be 0.60 and 0.37 for copper, 0.51 and 0.32 for zinc, 0.32 and 0.20 for lead, and 0.50 and 0.25 for cadmium. These findings indicated that ryegrass is a promising accumulator plant and able to uptake and translocate the heavy metals copper, zinc, lead or cadmium from contaminated soil. REFERENCES: Badr, N., Fawzy, M. and Al- Qahtani, K. (2012). World Applied Sciences Journal 16: Glick, B. R. (2003). Biotech. adv. 21: Luo, Y. Zhang, H. and Chen Tu (2012). Duke Energy Convention Center, Room 262, Level 2. Macek, T. ; Mackova, M and Kas, J. (2000). Biotech. Adv. 18: Marcovecchio, J. E., Botte, S. E., Freije, R.H. (2007). In: Nollet, L.M.L. (Ed.), Handbook of water analysis, 2 nd ed. CRC Press, Boca Raton, pp McKinlay, R. and Kasperek, K. (1999). Water Res. 33: Olowoyo, J.O., Okedeyi, O.O., Mkolo, N.M., Lion, G.N. and Mdakane, S.T.R. (2012). South African J. Botany, 78: Perez, J.; Garcia, G and Esparza, F. (2002). A vance y Perspect. 21: Susarla, S. ; Medina, V.F. and McCutcheon, S.C. (2002). Ecol. Eng. 1818: Xia, H. ; Wu, L. and Tao, Q. (2003). J. Appl. Ecol. 14: OBJECTIVES: Soil contamination by metals is one of the most critical environmental problems. The currently used techniques either landfilling or metal extraction using toxic agents as well as the use of metal-chelating bio-surfactant for soil remedy need to be replaced by green technology solution. Therefore, the research was designated to study the ability of plants to bio-accumulate, translocate and remove some metals such as zinc, copper, lead and cadmium from contaminated soil. This method does not usually produce toxic by-products. It is also cheaper and effective technology with minimal impact on the environment and can be easily used for soil remedy. SPECTROSCOPIC ANALYSIS Plant and soil samples were subsequently analyzed for heavy metal contents, as dry weight basis, using an atomic absorption spectrometer (AAS). Measurements were made using the hollow cathode lamps for Cu, Zn, Pb, and Cd at the proper wavelength. Working solutions were prepared by dilution just before the use of standard solutions for atomic absorption spectroscopy ( 1000 ppm). For the determination, two solutions were prepared for each sample and three separate readings were made for each solution. The means of these figures were used to calculate the concentrations. INTRODUCTION: Soil contamination by heavy metals is one of the most critical environmental problems as it poses significant impacts to the human health as well as the ecosystems. Heavy metal contamination in soils can come from atmospheric fall-out, pesticide formulations, and contamination by chemical fertilizers and irrigation with water of poor quality (Marcovecchio et al, 2007 ). They cannot be destroyed biologically but are only transformed from one oxidation state or organic complex to another pollution poses a great potential threat to the environment and human health. The contaminants are able to infiltrate deep into the layer of underground waters and pollute the groundwater as well as the surface water. Heavy metals in the soil subsequently enter the human food web through plants and they constitute risk to the ecosystem as they tend to bio-accumulate and can be transferred from one food chain to another. Heavy metals are discovered in various food chains where the results are usually detrimental to micro-organisms, plants, animals and humans alike. The use of plant species for cleaning polluted soils has gained increasing attention as an emerging effective and inexpensive technology (Macek et al, 2000, Susarla et al, 2002 and Xia et al, 2003 ) compared to other remediation methods, because it is a natural process and does not usually produce toxic by-products. It also has a minimal impact on the environment (McKinlay and Kasperek, 1999 ). Phytoremediation technologies are needed to replace currently used techniques of either landfilling or metal extraction using caustic or toxic agents. These plants are called hyper-accumulators that keep contamination from spreading to other areas through the action of wind, rain and groundwater (Perez et al, 2002, Glick, 2003, Olowoyo et al, 2012, Badr et al, 2012, Luo et al, 2012 ). METHODS & MATERIALS: Soil were sieved, dried and the pH value and organic matter were determined. Seedlings of herbal plants were cultivated in pots containing 100 g soil without any fertilizer and the plant left to grow under greenhouse conditions. Metal salts of copper carbonate, zinc carbonate, lead hydroxide carbonate and cadmium nitrate at different concentration levels of 0, 100, 200, 400 and 600 µg/g soil were spiked into the soil. Plants were removed after 60 days and divided into roots and shoots. Plant and soil samples were dried at 105 °C in an oven for 24 h and powdered and digested with nitric acid. Samples were put in a muffle furnace at 600 °C for ashing. The ash was rinsed with 1.0 M nitric acid and filtered to be ready for analysis. CONCLUSIONS: The investigated herbal plant is a good accumulator for Cu, Zn, Pb or Cd. The soil-plant transfer factor (the conc. of heavy metal in plant to the conc. in soil) indicated that the mechanism of soil remedy using the investigated plant is phytoextraction where the amounts of heavy metals transferred by plant roots into the above ground portions were higher than that remained in the soil. Phytoremediation offers green technology solution to the problem because it does not usually produce toxic by-products. In addition, it is cheaper and effective technology with minimal impact on the environment and can be easily used for soil remedy.