Determination of Heavy Metal Deposition in the County of Obrenovac (Serbia) Using Mosses As Bioindicators. I: Aluminum (Al), Arsenic (As), and Boron (B)
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Arch. Biol. Sci., Belgrade, 57 (3), 205-212, 2005. DETERMINATION OF HEAVY METAL DEPOSITION IN THE COUNTY OF OBRENOVAC (SERBIA) USING MOSSES AS BIOINDICATORS. I: ALUMINUM (AL), ARSENIC (AS), AND BORON (B) M. SABOVLJEVIĆ1,4, V. VUKOJEVIĆ1, NEVENA MIHAJLOVIĆ2, GORDANA DRAŽIĆ2, andZ. VUČINIĆ3 1Institute of Botany and Jevremovac Botanical Garden, Faculty of Biology, University of Belgrade, 11000 Belgrade, Serbia and Montenegro 2INEP, 11080 Zemun, Serbia and Montenegro 3Center for Multidisciplinary Studies, University of Belgrade, 11000 Belgrade, Serbia and Montenegro 4Nees Institute of Plant Biodiversity, Rheinische Friedrich Wilhelms University of Bonn, 53115 Bonn, Germany Abstract - In the present study, the deposition of three heavy metals (Al, As and B) in the county of Obrenovac (Serbia) is determined using four moss taxa (Bryum argenteum, Bryum capillare, Brachythecium sp., and Hypnum cupressiforme) as bioindicators. Distribution of average heavy metal content in all mosses in the county of Obrenovac is presented in maps, while long-term atmospheric deposition (in the mosses Bryum argenteum and B. capillare) and short-term atmos- pheric deposition (in the mosses Brachythecium sp. and Hypnum cupressiforme) are discussed and given in tables. Areas of the highest contaminations are highlighted. Key words: Heavy metal deposition, mosses, bioindicators, Serbia UDC 582.32(497.11Obrenovac):581.5 INTRODUCTION Mosses are better than other higher plants in scan- ning heavy metal deposition because: Surveillance of heavy metals in mosses was originally -they are perennial without deciduous periods; established in the Scandinavian countries in the 1980s. -they have high cation exchange capacity that allows However, the idea of using mosses to measure atmos- them to accumulate great amounts of heavy metals pheric heavy metal deposition was developed alredy in between the apoplast and symplast compartments the late 1960s (Rhülingand Tyler, 1968; Tyler, without damaging vital functions of the cells; 1970). It is based on the fact that mosses, especially the -mosses do not possess thick and strong protective carpet-forming species, obtain most of their nutrients layers like cuticles. directly from precipitation and dry deposition. In the present investigations, we decided to use two acrocar- Also, this time-integrated way of measuring patterns pous moss species (Bryum argenteum Hedw. and Bryum of heavy metal deposition from the atmosphere to terres- capillare Hedw.) that can give us an idea of long-term trial ecosystems, besides being spatially oriented, is easi- atmospheric deposition, inasmuch as they are attached to er and cheaper than conventional precipitation analyses, the substrate and also accumulate metals deposed during as it avoids the need for deploying large numbers of pre- the last few decades in the surface layers of the substrate. cipitation collectors. The higher trace element concentra- tion in mosses compared to rain water makes analysis Two pleurocarpous taxa (Brachythecium sp. and more straightforward and less prone to contamination Hypnum cupressiforme Hedw.) were used to scan short- (Berg et al. 1997). term atmospheric deposition of heavy metals, consider- ing that these taxa are not strongly attached to the sub- Use of mosses to investigate heavy metal deposition strate and accumulate mostly from precipitation. shows transboundary heavy metal pollution and can indi- 205 206 M. SABOVLJEVIĆ et al. cate the paths by which atmospheric pollutants enter from the presence of all investigated species and yearly bio- other territories or reveal their sources within the investi- mass. More than 500 samples were analyzed. gated area. After collecting, samples were dried as soon as pos- Although 15 heavy metals were analyzed in all, only sible in a drying oven to constant dry weight (dw) at a deposition and distribution of aluminum, arsenic and constant temperature of 350C, then stored at -200C. Fol- boron are treated in the present study. lowing homogenization in porcelain, the samples were treated with 5+1 parts of nitric acid and perchloric acid MATERIAL AND METHODS (HNO3:HClO4 = 5:1) and left for 24 hours. After that, a Kjeldatherm digesting unit was used for digestion at 150- The acrocarpous mosses Bryum argenteum and 2000C for about one hour. Digested samples were filtered Bryum capillare were used to research long-term atmos- on qualitative filter paper to dispose of silicate remains. pheric deposition, while the pleurocarpous Brachytheci- Sample volume was then normated to 50 ml. Aluminum um sp. and Hypnum cupressiforme were used to scan (Al) was detected by AAS on a Pye Unican SP9 atomic short-term atmospheric deposition in the county of absorbance spectrophotometer from Philips using the Obrenovac (Serbia). Hypnum cupressiforme is one of the flame of acetylene/nitrogen-suboxide. Boron (B) was standard species used in Europe to survey heavy metal detected by ICP-ES, while arsenic (As) was determined deposition (Buse et al. 2003.), while the other three are by AAS using hydride techniques. standard in Europe, but do not grow in this region. In esti- mating which other species are eligible for use in heavy For explanation of the results and their presentation metal deposition monitoring, we relied on the experience on maps, the folloving statistical statistics parameters of Thöni (1996), Herpin et al. (1994), Siewers and Hair- were used: average values, standard deviation, minimum, pin (1998) Zechmeister (1994), and Ross (1990). maximum, and percent deviation. Map making and inter- polation of exact data were made using Agis software As far as possible, moss sampling was conducted (v1. 71 32 byte, © Agis Software, 2001). according to guidelines, set out in the experimental pro- tocol for a survey carried out in 2000/2001 (UNECE, RESULTS AND DISCUSSION 2001). Details of the procedure are given in Rühling et al. (1998). Aluminum in Obrenovac County probably comes from heavy road traffic, intensive coal burning, and Each sampling site was located at least 300 m from incorrect waste disposal. The most contaminated areas main roads and populated areas and at least 100 m from according to deposition in mosses are the town of Obren- any road or single house. In forests or plantations, sam- ovac and the northernmost part of the county by the Sava ples were collected in small open spaces to preclude any River (>40 mg/g). A somewhat lower level of Al deposi- effect of canopy drip. Sampling and sample handling tion (20-30 mg/g) occurs in the central part of the coun- were carried out using plastic gloves and bags. About ty, where Al is probably spread by traffic on the main three moss samples were collected from each site. Dead roads. material and litter were removed from the samples. Green parts of mosses were used for the analyses. Aluminum represents 8% of the Earth's crust. It comes from bauxite (Merian, 1984), is very wide- The county of Obrenovac was chosen for this inves- spread in all forms of industry (machine construction, tigation because of its industry and location. Each sam- electro engineering, civil engineering, the food industry, pling site was GPS located with a precision of ±10 m, and agriculture), and is also present in aluminum foil, iron GPS dates (Germin) were digitalized on the maps using plates, and other widely used articles. Aluminum emis- the following softwares: OziExplorer 3.95.3b, © D&L sion into the atmosphere was great during the last centu- Software Pty Ltd, and WinDig 2.5 Shareware, © D.Lovy. ry. Only in the 70s it was 7.2 million tons per year All material was collected during November of 2002. Not (Lantzyand Mackenzie, 1979). It is known that more than one site was chosen in a 50x50 m square. the atmospheric concentration of aluminum is signifi- Seventy-five localities were chosen out of 129 for com- cantly elevated (>10mg/m3) in areas with a cement indu- parisons and further analyses. The selection was based on DETERMINATION OF HEAVY METAL DEPOSITION IN THE COUNTY OF OBRENOVAC (SERBIA) 207 Fig. 1. Exact locations of moss sampling (left) and extrapolated maps (right) of selected heavy metal deposition in the county of Obrenovac (Serbia). stry (Merian, 1984). Arsenic and boron are probably spread in the coun- ty of Obrenovac by wind blowing from coal ash deposit In slightly acid and neutral soils, dissolving of alu- sites. According to the mosses analyzed, the center of minum is inconsiderable, while in acid soils (pH<5.0) the arsenic deposition is the southwestern part of the county concentration of Al3+ is significantly elevated. High con- around the village of Vučičevica. However, there is a centrations of Al3+ in the substrate exert toxic action on rather large area in the western part of county with aver- plants by damaging the roots and by lowering the uptake age arsenic deposition of 000.7-000.9 mg/g (dw of moss- of essential phosphorous, calcium, and magnesium es). Some smaller areas with high arsenic deposition are (Bergmann, 1988). Aluminum is also toxic for ani- also are present in the town of Obrenovac and around mals and man, especially if its concentration is high in Barič. The highest presence of boron is in the southwest- water and if air with a high concentration of it is inhaled ern part of Obrenovac County, where its concentra- over longer period. It can cause Alzheimer's disease tion is more than 1.2 mg/g. Some zones with medium (Merian, 1984). In drinking water, the maximal toler- concentrations (0.4-0.8 mg/g) are found in the town ated value of aluminum concentration