Evolution in time of soil heavy metals contamination in Zlatna region, Romania

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1 Evolution in time of soil heavy metals contamination in Zlatna region, Romania GABRIELA-ALINA DUMITREL 1, MIREL GLEVITZKY, MARIA POPA, ADRIAN EUGEN CIOABLA 3, FRANCISC POPESCU 3 1 Faculty of Industrial Chemistry and Environment, Politehnica University of Timisoara, 6 Vasile Parvan Blvd, 3003 Timisoara Faculty of Science, University 1 Decembrie 1918 of Alba Iulia, Nicolae Iorga Str Alba Iulia 3 Faculty of Mechanical Engineering, Politehnica University of Timisoara, Mihai Viteazu Blvd. no.1, 300 Timisoara ROMANIA mirel_glevitzky@yahoo.com Abstract: - Soil pollution with heavy metals is a current problem with serious consequences on health. Heavy metals in small quantities are needed for all vital forms. In the organism cells, metals are presented as cations, but their inclusion is strictly regulated because, in large quantities, they are toxic. This paper aims to determine the soil pollution with heavy metals in eleven points of Zlatna area, in two different periods of time: 004 and 01. The results show a heavy metals content (lead, copper and cadmium) exceeding the limits set by European legislation. In the mean time, the need of a strategic rehabilitation of Ampoi Valley Basin was highlighted, given the fact that in 004 the activity of copper smelter plant had been stopped. Key-Words: - soil, mining activities, cooper processing, heavy metals, pollution 1 Introduction Pollution of the natural environment by heavy metals is a world-wide problem. Due to polluted human activities (industrial, mining and agricultural activities, road transport) the level of heavy metals increases continuously. Heavy metals are included in the category of persistent substances with factor of risk, which have the tendency to accumulated in the trophic chains, generating a significantly unwanted effect to alive organisms [1]. The soil is a dynamic system where short-term fluctuations occur, such as variations in humidity, ph levels and redox conditions; it is also the place where the organic matter gradually decomposes as a consequence of changes in nature. These changes alter the shape and availability of metal ions and therefore they must be taken into account when making a decision on soil pollution or waste storage []. The rate of migration of heavy metals in the soil tends to be relatively slow during the initial 10 years [3, 4]. The continuous migration of heavy metals has contributed to making the subsurface hydrological subdivision of vadose zone to be a sinks for migrated contaminants from the soils, from which groundwater may be contaminated. The increase of the natural soil acidity up to ph values and soil loading with heavy metals at content levels exceeding up to 41 (Pb), 11 (Cu), 7 (Zn), 4 (Cd) times the maximum allowable limits contributed to soil base depletion, microbiological activity disturbance, organic matter degradation, soil structure deterioration [5]. The physical and chemical analysis revealed that heavy metals and organic matters are concentrated in the soil whose ph KCl ranges from 3.7 to 5.. Heavy metals decrease with depth within same soil profile. The three forms of land degradation have affected the distribution of heavy metals. Oil spillage has caused an increase in the concentration of Ni +, V + and reduction in Fe + and Pb + ; bush burning was responsible for increase in the concentration of Ni +, V +, Fe + and reduction of Pb + ; while erosion has so caused increase in the concentration of Ni +, V +, Pb + ; and reduction in Fe [6]. Many published data are available on heavy metal concentrations in soils from Ampoi River Valley and soil from Zlatna town, but the main aim ISBN:

2 of this study is to monitor and compare the value of different parameters of soil from Zlatna region between the year 004 and 01. Experimental The study area is located in Alba County, Apuseni Mountains in Western Romania. It covers Zlatna town, witch is located 37 km north-west of Alba Iulia, in the Zlatna depression. The major pollutants of Zlatna area were: Ampellum Company (copper smelter plant) with pollutants emitted into the air: particulate matter containing zinc, lead, cadmium, arsenic, copper and SO, SO 3, CO; in water: Zn +, Cd +, As +3, Fe + /Fe +3, SO 4 - (River Ampoi); on ground: particulate matter of zinc, lead, copper, arsenic and cadmium; respectively Zlatna mining with pollutants emitted in water: suspended particulate matter, cyanide, iron, copper, zinc (Ampoi River); on the ground: tailings dump. The sampling section was located just in Zlatna town and near the Ampoi River, also in Zlatna. On July 004 and 01 soil samples were collected from Zlatna town, according to the figure 1. Figure 1. Studied area and the sampling points The pattern small grid represent the former location of Ampellum Company from Zlatna and the full gray area is the slag dumps located downstream of the factory specialized on the metallurgy of cooper. Table. The soil sampling points. Sample Sampling place Right bank of the Ampoi river, 100 m upstream from the processing plants The yard of plant no.1, in the neighborhood of concentrated deposit The yard of plant no.1, in the neighborhood of control laboratory Dump on the right bank of Ampoi river, 300 m downstream of the plant no. 1 Dump on the right bank of Ampoi river, 800 m downstream of the plant no. 1 administrative building transport offices metallurgy building Outside Ampelum company, in front of grocery store Downtown Zlatna, near S.M. Zlatna headquarters Right bank of the Ampoi river, 100 m downstream of the processing plants and Ampelum society Soil samples were dried for 7 days at 40 C, sieved to less than mm in a plastic sieve and ground to a fine powder using an agate ball mill. Soil ph was determined according to SR ISO 10390:1999 [7]. Soil samples, treated as describe above, were mixed with potassium chloride solution 1 mol L -1 in a 1:5 (g:ml) ratio and shacked for 15 min before measuring. For heavy metal measurement, the samples preparing method was the wet mineralization by using nitric and perchloric acid. The concentration of all soil heavy metals were measured by atomic absorption spectrophotometry [8,9]. g of soil sample (air dried and sieved to mm) were introduced in a Berzelius glass onto which was added approx. 5 ml concentrated nitric acid. The beaker was covered with a watch glass and the composition was mineralized on sand bath. After entire nitric acid vaporization, cm 3 of perchloric acid was added and the mineralisation continued. The residue was re-treated with a 4% solution of nitric acid and easily heated to facilitate the solubilization. After cooling, the suspension was passed through low porosity filter paper into a 5 cm 3 volumetric flask. The filter was washed with distilled water and the volumetric flask was filled to the ring graduation mark. Using a Perkin Elmer atomic absorption spectrophotometer, the concentration of soil heavy metals was measured in mg/l. ISBN:

3 In order to express the quantity of heavy metal in soil with respect to quantity of soil, the next relation was used. µ g Heavy metal + 0 / g soil dried at 105 C= 1.5 c K were: K = m-m 1 humidity of soil air-dried during 4 hours m mass of fresh soil sample, [g] m 1 mass of soil air-dried during 4 hours, [g] c heavy metal concentration measured [mg/l] 3 Results and discussion The ph values of soil samples collected are presented in figure p H Sample Figure. Variation of ph values in soil samples The ph values of soils were generally situated between 4.3 and 8.1 in 004, respectively 7.4 and 7.7 in 01, due to their buffering quality. Thus, we can say that in 004 the soil was acid (sample no. 5, 6, 7 and 9), low acid (sample no 8) and alkaline (sample no. 1,, 3 and 10).Tests carried out in 01 have been showed that the soil ph become uniform and it could be considered neutral. This feature is important for agricultural soils. However, the microorganism s activity is influenced by soil reaction, so nitrifying bacteria and nitrogen-fixing bacteria grow better in slightly alkaline soils. Soil reaction also influences nutrient uptake by plants and microorganisms. For each soil sample the following heavy metals concentrations were determined: Pb, Cu and Cd. The measured values are presented in figures 3, 4 and 5 together with normal values (NV), Alert threshold sensitive uses (ATS), Alert threshold less sensitive uses (ATLS), Intervention threshold sensitive uses (ITS), Intervention threshold less sensitive uses (ITLS). Since the analysis of samples were made before and after Romania joined the European Union (004 and 01), the values obtained were reported to the ones established by the order no. 756/1997. The concentration of Pb + in soil samples collected in 004 exceeds the intervention threshold in most sampling points (except sample 1, 10 and 11). After 8 years from first sampling and also from the closure of the plant considered as the main source of pollution, the concentration of Pb + remains above normal values imposed by the law in most sampling points, but much lower than the initial values. Soil pollution with copper was recorded in all investigated points. Copper content in soils in Zlatna area achieve de maximum level in 004, near the metallurgy building (up to mg/kg). There is a significant decrease of Cu + content in all sampling points in 01. However, even in present, the values are far beyond the normal values. The cadmium content also exceeded the normal limit values established by legislation, with a maximum value for soil sample collected from inside of former Ampelum factory, near the metallurgy plant. It was noticed a decrease in time of Cd + concentration, but the values were slightly higher than the normal ones. Generally, the concentrations of heavy metals in soil samples coming from the yard of copper smelter plant were higher, but soil samples coming from Zlatna town and the neighborhood of the slag dumps presented high values, also. The concentration of Pb, Cu and Cd in the soil sample was much higher that value of intervention threshold for less sensitive uses (ITLS). This could be due to the action of atmospheric factors (especially wind and rain) who determined the pollution migration away from the source. The decrease of soil heavy metals content between 004 and 01 was possible thanks to soil remediation strategies applied after the closure of the main pollution source. ISBN:

4 Figure 3. The concentration of lead in soil samples Figure 4. The concentration of cupper in soil samples Figure 5. The concentration of cadmium in soil samples ISBN:

5 4 Conclusion Analysis of soil samples from eleven points in Zlatna region revealed an evident accumulation of lead, copper and cadmium determined by the long term action of the polluting source in the area. The effect of pollution was higher as the soil ph was lower and the distance to the pollution source was smaller. The concentrations of those heavy metals were higher than the value of intervention threshold for less sensitive uses (ITLS) in 004, but decrees significant till 01, due to soil remediation strategies applied after the closure of the main pollution source. [9] SR ISO 11047: Soil quality. Determination of cadmium, chromium, cobalt, copper, lead, manganese, nickel and zinc in aqua regia extracts of soil Flame and electrothermal atomic absorption spectrometric method References: [1] G. Vasile, L. Cruceru, Optimized method for extraction of mobile species of heavy metals from polluted soils, Journal of Environmental Protection and Ecology, Vol.8, No.4, 007, pp [] M. Popa, M. Jitaru, Study on Heavy Metal Accumulation Level of Soils from Zlatna Region, Chemical Bulletin of Politehnica University of Timisoara Series of Chemistry and Environmental Engineering, Vol. 50, No. 64, 005, pp [3] S. Hellweg, T.B. Hofstetter, K. Hungerbuller, Time-Dependent life Cycle Assessment of Emission from Slag landfills with the help of Scenario Analysis: The Example of Cd, and Cu, Journal of Cleaner Production., Vol. 13, No. 3, 005, pp [4] M. Majone, M.P. Papini, E. Rolle, Influence of Metal Speciation in Landfill Leachates on kaolinite Sorption, Waste Resources, Vol. 3, No. 3, 1998, pp [5] R. Lacatusu, M. Dumitru, I. Risnoveanu, C. Ciobanu, M. Lungu, S. Carstea, B. Kovacsovics, C. Baciu, Soil Pollution by Acid Rains and Heavy Metals in Zlatna Region, Romania, The 10 th International Soil Conservation Organization Meeting, May 4-9, 1999 [6] O.A. Oghenero, Heavy metals distribution in degraded land forms in Delta State of the Niger delta, Journal of Geology and Mining Research, Vol. 4, No. 3, 01, pp [7] ISO 10390: Soil Quality Determination of ph [8] ISO 11466: Soil Quality Extraction of Trace Elements Soluble in Aqua Regia. ISBN: