Heavy metals contamination of soils surrounding ...

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immobilisation with different species of plants (Elaeagnus angustifolia, Robinia pseudaccia, Hippophae rhamnoidesy. The phytoremediation technique also ...

J Phys. IV France 107 (2003) © EDP Sciences, Les Viis

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DOl: 10.1 051/jp4:20030431

Heavy metals contamination of soils surrounding waste deposits in Romania M. Matache, L. Rozylowicz,

M. Ropota and C. Patroescu

University of Bucharest, Centre for Environmental Research and Impact Studies, 1 Nicolae Balcescu Blvd., Sector 1, 70111 Bucharest, Romania

Abstract. Soils contamination with heavy metals is one of the most severe aspects of environmental pollution in Romania, independently of the origin sources (domestic or industrial activities) or type of disposal (organised landfill or hazardous deposits)[1-2]. This fact is the consequence of the poor state of the existing waste deposits in Romania and of the significant costs involved by the establishing of a new landfill according with the international regulations. The present study is trying to emphasise the contamination of soils surrounding different categories of waste deposits (sewage sludge ponds, domestic and industrial waste landfills, hillocks, sterile deposits) from various regions of Romania. Some case studies show a special interest being localised in a protected area (Iron Gates Natural Park). In order to quantify the concentration of metals like Cd, Cr, Cu, Pb, Zn, Ni, Mo in soil samples, analysis were performed using Inductively Coupled Plasma - Optical Emission Spectrometry (lCP-OES). Romanian standards were used as reference values [3].

1. General description Four case studies were considered: a) Sf. Gheorghe city municipal landfill - contains both industrial and domestic wastes; located in the Olt river floodplain; the landfill also includes a pond that contains the sewage sludge resulted in the wastewaters treatment plant; Sf. Gheorghe is localised in the central part of Romania. b) Brasov treatment plant sludge pond - contains the sludge that results in the treatment process of both industrial and domestic wastewaters from Brasov city area; Brasov is localised in the central part of Romania. c) Baia Noua coal mine sterile deposit - the sterile is deposited directly on the ground, no special measures being taken (liner and intermediate caps are missing); located in the Iron Gates Natural Park; Baia Noua is localised in the south-western part of Romania. d) Moldova Noua sterile deposit from copper ores extraction and processing plant - main raw material is calcopyrite; located in the Iron Gates Natural Park, on the Danube river left shore; safety measures extremely poor, frequent releases into the river waters determining sediments contamination [4]. Moldova Noua is localised in the south-western part of Romania. The study considered of interest cadmium, chromium, copper, nickel, lead and zinc. 2. Sampling and analytical method In order to properly quantify the pollution effects on soil quality, the team opted for an exploratory sampling that according to literature seemed to be the most adequate. The sampling plan was designed according to the presumed causes of disturbances, considering the disturbances nature and the natural division of the landscape [5, 6]. Two sampling depths were used for each vertical: at 5 cm and at 35 cm. Soil samples were digested in an open system with concentrated acids (hydrochloric, hydrofluoric, perchloric, nitric); then, filtrated on Whatman No. 54 paper; the residue suffers an alkaline melting with borax and sodium carbonate. The analytes are determined in both filtrates and the total was calculated by adding the two values. Concentration of microelements was quantified using Inductively Coupled Plasma

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3. Results and discussions Analysis performed on the soil samples from the neighbourhood of the landfill and sludge pond showed serious contaminations with heavy metals of the surrounding environment. The company managing the landfill from Sf Gheorghe must pay a special attention to cadmium and lead, a large majority of the samples exceeds even the alert rank (see Figures 1 and 2 - Normal values and alert rank according to Romanian legislation). 160 -,-------------------,

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Figure 1. Cadmium distribution in soil samples from Sf Gheorghe.

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Figure 2. Lead distribution in soil samples from Sf Gheorghe,

Cadmium and lead sources are probably batteries deposited directly in the landfill although they are considered as extremely hazardous substances and request special measures [7]. Maximal values for all considered elements were registered in sampling site no. 4, located nearby the sewage sludge pond. 120,---------------

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Figure 3. Cadmium distribution in soil samples from Brasov

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Figure 4. Lead distribution in soil samples from Brasov

Cadmium and lead are the main problem also for the sludge pond in Brasov, but the number of samples exceeding the alert ranks is smaller than in Sf Gheorghe (see figures 3 and 4). The values

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request for an improvement of the wastewaters treatment process. A contribution to lead input in the city sewerage system belongs to the traffic of vehicles using lead fuels enriched with tetraethyllead. Before analysing the soil samples from the areas surrounding the two sterile deposits, we performed analysis on sterile composition in micro elements. The analysis indicated a high concentration of nickel in the coal sterile (average value of 35.9 ppm) and, as expected, high amounts of copper in the sterile from Moldova Noua deposit (average value of34.5 ppm). For the samples obtained at Baia Noua, influences of the sterile deposit were noticed in what regards the level of nickel. It is necessary to mention that the samples with high amounts of nickel were taken from areas with mechanical disturbed soils (the result of mixing soil and sterile), being impossible to individualise the two components. As expected, the soil samples from Moldova Noua emphasise soil contamination with copper (see figure 5). In the sampling points 1, 2 and 3, the soil was mechanical disturbed and mixed with sterile washed from the deposit due to insufficient isolation of it. Precipitations water dissolves trace elements from the sterile and transfers them to the soils surrounding the deposit despite sterile deposit immobilisation with different species of plants (Elaeagnus angustifolia, Robinia pseudaccia, Hippophae rhamnoidesy. The phytoremediation technique also requires that after a certain period, the plants are harvested, burned and trace elements extracted from ash, but this phase was not even considered in the ecological restoration plan for the deposit in Moldova Noua. The percolation process might also generate accumulation of pollutants in lower strata of the soil horizon, in the conditions of a reduced cationic exchange capacity of the soil. This process is suggested by the fact that the highest value for copper was registered in the sample from 35 cm depth. 160

Figure 5. Copper distribution in soil samples from Moldova Noua

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Conclusions Since the considered case studies are from different regions of Romania in which different human activities developed (municipal landfi1l, sterile deposit, sewage sludge pond), we might conclude that the waste deposits older than 5-10 years are a major threat for the environment quality. Soils contamination appears frequently in areas located close to waste deposits. In all four cases that we have considered, at least one of the indicators is exceeding the normal values of concentration in soils. The wastewaters treatment plants must improve their performances in what regards elimination of trace elements from the wastewaters. Also important to emphasise is the fact that no preliminary separation is performed for domestic and industrial wastes or wastewaters, which might generate synergic effects of pollutants. The use of phytoremediation techniques can be a solution for limiting sterile

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deposits effects on surroundings, but conditioned by the full performing of it (seeding, plants growth, harvesting, harvest combustion, micro elements recovering from ash). The waste deposits require a continuous careful monitoring in order to emphasise any accidental release of toxic compounds into the environment components (e.g. groundwater contamination, aquatic ecosystems perturbation etc.). References [1] Lacatusu, R., Risnoveanu, I., Kovacsovics, B., Lungu, M., Stiin,fa Solului 34 (2000) [2] Matache, M., Rozylowicz, L., Ropota, M., "Wastes deposits and their impact on environment quality. Case study: Sfantu Gheorghe city, Covasna county", Proc. of 5th Syrnp. on Envir. Contam. in Central and Eastern Europe, Prague, September 12-14, 2000, published by Institute for International Cooperative Environmental Research, Florida, USA [3] MAPPM - Ministerul Apelor, Padurilor ~i Protectiei Mediului, 1997, Ordinul Ministrului Apelor, Padurilor §i Protectiei Mediului nr. 756/3 noiembrie 1997 privind Evaluarea poluarii mediului [4] Matache, M., Patroescu, c., Patroescu-Klotz, I. V., Rev. de Chim., 53, September 2002 [5] Crepin, J., Johnson, R. L., 1993, Soil Sampling for Environmental Assessment in Soil Sampling and Methods of Analysis, edited by Carter, R. M., LEWIS Publishers, Boca Raton, 823 p. [6] Davis, J. C., 2002, Statistics and Data Analysis in Geology, 3rd ed., John Wiley, 638 p. [7] US EPA., Alphabetical order list of extremely hazardous substances, www.epa.gov, February 1999

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