Source identification of heavy metals in atmospheric dust using Platanus orientalis L. leaves as bioindicator

Abstract

Studies on atmospheric dust have been limited by the high cost of instrumental monitoring methods and also sampling difficulties. The use of organisms acting as bioaccumulators has recently been proposed. In this study, the leaves of Platanus orientalis L., as a possible biomonitor of heavy metals in atmospheric dust, were evaluated to understand the likely source(s) of pollution in Isfahan, Iran. Concentration of Zn, Cu, Ni and Mn and Magnetic susceptibility (χ_lf) were determined in washed (WL) and unwashed leaves (UL), monthly sampled from May to Nov., 2012. By subtracting the amount of metal concentrations and χ_lf in UL and WL, the amount of these parameters in dust deposited on the leaves (UL-WL) were calculated. Enrichment factor analysis (EF), correlation coeficient, principal component analysis (PCA) and cluster analysis (CA) on the UL-WL data were employed to trace the heavy metals sources. Results showed that the metal concentration in UL and WL in primary sampling times was not statistically different. As time passed, this difference became more noticeable. Seasonal accumulation trends of elements concentration in UL-WL, referred to as accumulative biomonitors showing the accumulation of dust on the leaves are considerable and the contamination of plants by metal occurs mainly by retention of particulate matter. All the heavy metals are well correlated with χ_lf, indicating the potential of magnetic measurement as an inexpensive and less laborious method to estimate heavy metals. Cu and Zn exhibited a very strong correlation with each other and the highest correlation with χ_lf, suggesting an anthropogenic nature of these two metals. High EF of Cu and Zn showed that anthropogenic sources contribute a substantial amount of these metals to dust deposited on leaves. Whereas, less EF for Mn and Ni shows that natural source and local polluted soils might be the main origins of these metals. PCA results showed 2 principal components. Factor 1 with significant loading for Cu and Zn and factor 2 for Mn and Ni. In an agreement with the PCA and correlation results, CA showed strong clusters for Zn and Cu and also for Mn and Ni. Zn seems to originate from vehicular emissions, oil combustion and wear and tear of vehicle tires. Cu seems to originate from industrial processes, traffic and combustion of fossil fuels. Polluted soils in the area appear to be the main natural source for Mn and Ni in dust, while anthropogenic activities could be considered as the second origin.

Keywords

• Tree leaves, Heavy metals, Magnetic susceptibility, Enrichment Factor, Multivariate statistics

References

1. Al-Khashman, O.A., 2007. Determination of metal accumulation in deposited street dusts in Amman Jordan. Environmental Geochemistry and Health 29: 1–10.
2. Al-Khashman, O.A., Al-Muhtaseb, A.H., Ibrahim, K.A., 2011. Date palm (Phoenix dactylifera L.) leaves as biomonitors of atmospheric metal pollution in arid and semi-arid environments. Environmental Pollution 159: 1635-1640.
3. Amiri, S., 2012. Effects of land use and parent material on the spatial distribution of topsoil magnetic susceptibility in eastern Isfahan. A thesis for the degree of Master of Science. Isfahan University of Technology, pp.132. (In Persian).
4. Anicic, M., Spasic, T., Tomasevic, M., Rajsic, S., Tasic, M., 2011. Trace elements accumulation and temporal trends in leaves of urban deciduous trees (Aesculus hippocastanum and Tilia spp.). Ecological Indicators 11: 824-830.
5. Basha, S., Jhala, J., Thorat, R., Goel, S., Trivedi, R., Shah, K., Menon, G., Gaur, P., Mody, K. H., Jha, B., 2010. Assessment of heavy metal content in suspended particulate matter of coastal industrial town, Mithapur, Gujarat, India. Atmospheric Research 97: 257-265.
6. Callén, M.S., de la Cruz, M.T., López, J.M., Navarro, M.V., Mastral, A.M., 2009. Comparison of receptor models for source apportionment of the PM10 in Zaragoza (Spain). Chemosphere 76: 1120–1129.
7. Celik, A., Kartal, A.A., Akdogan, A., Kaska, Y., 2005. Determining the heavy metal pollution in Denizli (Turkey) by using Robinio pseudo-acacia L. Environment International 31: 105-112.
8. Davila, A.F., Rey, D., Mohamed, K., Rubio, B., Guerra, A.P., 2006. Mapping the sources of urban dust in a coastal environment by measuring magnetic parameters of Platanus hispania leaves. Environmental Science and Technology 40: 3922–3928.

9. EPA, 1996. Environmental Protection Agency, Method 3052, SW-846.
10. Gao, Y., Nelson, E.D., Field, M.P., Ding, Q., Li, H., Sherrell, R.M., Gigliotti, C.L., Van Ry, D.A., Glenn, T.R., Eisenreich, S.J., 2002. Characterization of atmospheric trace elements on PM 2.5 particulate matter over the New York–New Jersey harbor estuary. Atmospheric Environment 36: 1077–1086.
11. Kardel, F., Wuyts, K., Babanezhad, M., Vitharana, U.W.A., Wuytack, T., Potters, G., Samson, R., 2010. Assessing urban habitat quality based on specific leaf area and stomatal characteristics of Plantago lanceolata L. Environmental Pollution 158: 788-794.
12. Kim, N.D., Fergusson, J.E., 1994. Seasonal variations in the concentrations of cadmium, copper, lead and zinc in leaves of the horse chesnut (Aesculus hippocastanum L.). Environmental Pollution 86: 89–97.
13. Lehndorff, E., Schwark, L., 2010. Biomonitoring of air quality in the Cologne Conurbation using pine needles as a passive sampler, Part III: Major and trace elements. Atmospheric Environment 44: 2822-2829.
14. Lehndorff, E., Urbat, M., Schwark, L., 2006. Accumulation histories of magnetic particles on pine needles as function of air quality. Atmospheric Environment 40: 7082-7096.
15. Lu, S.G., Zheng Y.W, Bai, S.Q., 2008. A HRTEM/EDX approach to identification of the source of dust particles on urban tree leaves. Atmospheric Environment 42: 6431-6441.
16. Lu, X., Wang, L., Li, L.Y., Lei, K., Huang, L., Kang, D., 2010. Multivariate statistical analysis of heavy metals in street dust of Baoji, NW China. Journal of Hazardous Materials 173: 744-749.
17. Mingorance, M.D., Oliva, S.R., 2006. Heavy metals content in N. oleander leaves as urban pollution assessment. Environmental Monitoring and Assessment 119: 57-68.
18. Niencheski, L.F.H., Baraj, B., Garcia Franca, R., Mirlean, N., 2002. Lithium as a normalizer for the assessment of anthropogenic metal contamination of sediments of the southern area of Patos Lagoon. Aquatic Ecosystem Health and Management 5 (4): 473-483.
19. Piczak, K., Lesnievicz, A., Zyrnicki, A., 2003. Metal concentrations in deciduous tree leaves from urban areas in Poland. Environmental Monitoring and Assessment 86: 273–287.
20. Qiu, Y., Guan, D., Song, W., Huang, K., 2009. Capture of heavy metals and sulfur by foliar dust in urban Huizhou. Chemosphere 75: 447–452.
21. Nazir, R., Shaheen, N., Shah, M.H., 2011. Indoor/outdoor relationship of trace metals in the atmospheric particulate matter of an industrial area. Atmospheric Environment 101: 765-772.
22. Salo, H., Bucko, M.S., Vaahtovuo, E., Limo, J., Makinen, J., Pesonen, L.J., 2012. Biomonitoring of air pollution in SW Finland by magnetic and chemical measurements of moss bags and lichens. Journal of Geochemical Exploration 115: 69-81.
23. Shah, M.H., Shaheen, N., 2010. Seasonal behaviours in elemental composition of atmospheric aerosols collected in Islamabad, Pakistan. Atmospheric Research 95: 210–223.
24. Szczepaniak, K., Biziuk, M., 2003. Aspects of the biomonitoring studies using mosses and lichens as indicators of metal pollution. Environmental Research 93: 221–230.
25. Tomasevic, M., Anicic, M., Jovanovic, L., Peric-Grujic, A., Ristic, M., 2011. Deciduous tree leaves in trace elements biomonitoring: A contribution to methodology. Ecological Indicators 11: 1689-1695.
26. Zhang, C., Huang, B., Piper, J.D.A., Luo, R., 2008. Biomonitoring of atmospheric particulate matter using magnetic properties of Salix matsudana tree ring cores. Science of the Total Environment 39(3): 177-190.