الفهرس 
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Abstract
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6: SUMMERY
A phyto-remediation greenhouse pot experiment and a chemo-remediation laboratory experiment, were conducted on 5 heavily polluted soils (high in six DTPA-extractable “soluble” heavy metals including 4 vital micronutrients) taken from different locations of industrial pollution in Qalubiya, Egypt. Two of the soils were from near a steel factory (S1 and S5), one by a fertilizer factory (S2), one near the Cairo-Alexandria high way (S3), and one by a metal smelter factory (S4). An additional soil non-contaminated, fertile normal arable soil (S6) was included in the phyto-remediation experiment. Status of soluble forms of the 6 metals “elements” of Fe, Mn, Zn, Cu, Ni, and Pb being (mg kg-1) as follows in the normal S6 soil: 4, 2, 0.8, 0.6, 0.1 and 0.1 respectively. Lowest values of the same elements in the contaminated soils are: 7(S3), 20(S1), 3(S3), 2(S1 & S2), 0.3(S1), 0.1(S3) respectively. Highest values: 40(S1), 64(S5), 70(S2), 13(S3 & S4), 3(S4), and 25(S5) respectively. The phyto-remediation experiment was conducted on the 6 soils using canola plant (Brassica napus) to remove amounts of the metals .
Samples of plants were taken at three stages (sampling dates): 38 days after seeding (before flowering) ; two days before applying the materials). 105 days after seeding (flowering),and 185 days after seeding (harvest). The chemo-remediation was conducted on the 5 contaminated soils to assess the extent of decreasing the solubility ( i.e. increasing the immobility)of the metals as a result of adding lime (L) “150 g kg-1 soil” , or peat-moss (M) “30 g kg-1” singly or combined
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(LM) , soil . Canola removed marked amounts of the heavy metals from soils. EDTA whether applied alone or augmented with SMB enhanced such removal ( via increased growth as well as increased metal contents on plant tissues)reflecting the increased availability of soil micronutrients caused by EDTA and the beneficial effect of SMB on helping solubilizing some non-soluble forms of heavy metals. Plants grew normally on all of the 5 contaminated soils, showing no visible symptoms of heavy metal toxicity, although in S1 (markedly polluted with soluble Fe and Pb) growth was retarded during the first 90 days, but recovered later on. Shoot growth in S1 was 10 - 35 % compared to that of other soils on day 38; increased to become 43- 73% on day 185 (plant harvest). Comparable values for root growth are 7- 20% on day 38 and 21- 43% on day 185 .This particular (S1) soil is adjacent to a steel factory and contained high contents of lead .It contained 120 mg total Pb kg-1 while the others contained high contents of lead. It contained 120 mg total Pb kg-1 while the others contained 8 to 106 mg total Pb kg-1; and contained highest soluble Fe .
The higher growth was associated with higher uptake (higher phyto-extraction) as well as contents of Mn, Zn, Cu, Ni, and Pb in plant tissues (roots and shoots). Growth enhancement by adding EDTA (singly or combined with SMB( persisted in all growth stages. EDTA increased the heavy metals in the roots far more than in shoots, suggesting an efficient ability in overcoming the diffusion limitation of metals to root surface than the barrier of root to shoot translocation. The chemo-remediation experiment showed that effectiveness ranked as
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follows L > LM > M indicating far higher efficiency of lime than peat moss to immobilize the heavy metals , and that it enhances peat for this purpose (synergistic effect) whereas peat moss does the reverse to lime (antagonistic effect. The decrease was more after 6 weeks than after 4 weeks of remediation. The percentage decrease (averages of all 5 soils) occurring was as follows regarding Mn, Zn, Cu, Ni, and Pb in the same respective order :First : following 4 weeks : (i) For L : 11.1 , 18.8, 9.6, 23.2, and 22.0 % . (ii) For M : 6.0, 7.4 , 4.3, 15.1, and 12.9 %. (iii) For LM: 8.7, 10.9, 3.5, 8.2, and 6.8%. Second : following 6 weeks: (i) For L: 34.2, 33.9, 43.4, 27.6, and 33.2 . (i) For M: 21.7, 13.2, 26.2, 20.7, and 20.5%. (iii) LM: 21.9, 27.0, 29.0, 27.6, and 33.2 % .
The considerable effect of lime in immobilizing heavy metals could be due one or more of: (1) tight adsorption of the metal upon the surface of the lime particles; (2) formation of strongly bound hydroxyl metal species; (3) precipitation of metals as hydroxides; (4) sequestration to enhance microbial activity. The immobilizing effect of peat moss on that could be due to one or more of: (1) formation of metal-humic acid complexes; (2) binding the metal with humic substances. The hampering effect of peat moss upon the effect of lime show decreases in metal immobilization by lime sue to its addition with lime 2.3, 0.8, 3.7, 8.1, 19.6, 16.3 regarding Mn, Zn, Cu, Ni, and Pb comparable to addition of lime alone. Peat moss could have released a portion of the metal precipitated by lime