engleski

Fitoakumulacija metala i metaloida iz tla onečišćenog ugljenim pepelom

Around the city of Tuzla, BiH, soil covered coal ash disposal sites have been used for food and fodder production since 1992. To the best of our knowledge this is the first report on the cultivation of coal ash disposal sites for agriculture purposes. During the war, in the nineties of the past century, the chronic lack of agricultural land in the area of thermo electric power plant, Tuzla (TEP) and in the surrounding area has forced refugees and local farmers to cultivate the surface of dried ponds in order to get arable land and to use it as pastures, meadows or for food production. Nowadays, 63 ha of soil covered disposal sites (Drežnik and Plane) are still used for agricultural purposes. High concentrations of As, B, Cr, Cu and Ni in alkaline (pH = 8.77 in 1M KCl, as 1:2.5 (w/v)) coal ash (analysed in aqua regia extract, HCl/HNO3 = 3:1 (v/v) on ICP-MS (ELAN 9000 DRC-e, Parkin Elmer) as 1:12 (w/v) were observed and their mass ratio were 112 mg As/kg, 204 mg B/kg, 281 mg Cr/kg, 85.9 mg Cu/kg and 593 mg Ni/kg, respectively. According to soil classification damage criteria the ash from Jezero disposal site belongs to the 5th class or waste soil in respect to As, Cr and Ni, further to the 4th class or polluted soil in respect to B and Cu, next to the 3rd class or high polluted soil in respect to Zn, Sr, Fe, Co and Cd, to the 2nd class or low polluted soil in respect to Cs, Pb, Rb and U and to the 1st class or clean soil in respect to Mo, P and Se, keeping in mind that this is ash not soil, but still this ash is used for food and fodder production. This study investigated metals (Cr, Cu, Ni, Cd, Mo, Cs, Co, Pb, Fe, Zn, Rb and Sr), metalloids (As and B), non-metals (Se and P) and actinide U transport and accumulation in winter barley (Hordeum vulgare L. cv. Rex) and soybean (Glycine max L. cv. Dora) grown on substrates made up of different soil and ash ratios, and six treatments were as follows: (1) soil / ash = 100 % mass / 0 % mass, (2) soil / ash = 0 % mass / 100 % mass, (3) soil / ash = 75 % mass / 25 % mass, (4) soil / ash = 50 % mass / 50 % mass, (5) soil / ash = 47.5 % mass / 47.5 % mass + 5 % mass saw dust amendment of beech tree and (6) soil / ash = 25 % mass / 75 % mass. After three vegetation seasons: two of winter barley (Hordeum vulgare L. cv. Rex) grown from 15.11.05. until 26.06.06. - barley (1) and from 09.11.06. until 18.06.07. - barley (2) and one of soybean (Glycine max L. cv. Dora) grown from 03.07.06. until 20.10.06., on the same substrate and in controlled conditions: yield components, total elements of nitrogen, sulphur, carbon and hydrogen in grain (by dry combustion method, Vario Macro CHNS analyzer, Elementar, 2006) and total elements (Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, Rb, Sr, U, Se, Zn, Cs, As, B and P) content in grain (in HNO3/H2O2 = 5:1 (v/v) extract, on ICP-MS at 1:30 (w/v) ratio) were determined for barley and soybean. Quality management, internal and external QC were conducted. The analyses of data observed in the experiment were performed by statistical Software SAS 9.1 (SAS Inst. Inc.). The level of significance was set at 5 % in all statistical tests. Soybean grain grown on pure alkaline coal ash or on its different soil mixtures was high accumulator, in at least one treatment, of B, Cd, P, Mo, Rb and Se, moderately accumulator of Cr, Cs, Cu, Ni and Zn, low accumulator of Pb and Sr and non accumulator of As, Co, Fe and U and barley grain grown on pure alkaline coal ash or on its different soil mixtures was high accumulator, in at least one treatment, of B, P, Mo, Rb and Se, moderately accumulator of Cs, Cu, Cd and Zn, low accumulator of Pb, Cr and Sr and non accumulator of As, Co, Fe, Ni and U. The observed data showed that barley and soybean were sensible and in their grains were high accumulators (EC > 1) of: P in all treatments of soybean and all treatments of barley ; Rb only in pure ash treatments of soybean and of barley ; Mo in all treatments of soybean and in some treatments (No. 1, 2 and 3) of barley ; Se in all treatments of soybean and all treatments of barley ; B in some treatments (No. 3, 4, 5 and 6) of soybean and in one treatment (No. 3) of barley ; Cd only in pure ash treatment of soybean. The content of As, Co, Cu, Fe, Pb and Zn in soybean and barleys grains was below normal values according to the available literature in all treatments, although a considerably high concentration of As and Cu was noted in the ash. These findings support the conclusion that very poor yields and visible plants damage in some treatments, especially in treatment with pure ash compared to treatment with pure soil of both species soybean and barley, were probably caused by toxicity (B, Ni, U, Mo) or deficiency (N, Cu, Zn, Fe). Non-essential trace elements (As, Co and Pb) were within normal concentration ranges and significantly below critical (1 mg As/kg, 1 mg Co/kg and 6 mg Pb/kg) levels in all treatments for both species.

metali; metaloidi; onečišćenje; tlo; ugljeni pepeo

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