Geospatial patterns and background levels of heavy metal in deposited particulate matter in Bushehr, Iran

• Published in: Arabian journal of geosciences 2015-04, Vol.8 (4), p.2081-2093
• Main Authors: Tabatabaei, T., Karbassi, A. R., Moatar, F., Monavari, S. M.
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Original Paper
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-013-1241-6

Dust storm transportation and deposition in Bushehr, Iran, caused adverse effects on regional air quality and human health. To evaluate the impact of these phenomena, it is critical to clarify the chemical characteristics and trace the sources of heavy metals in a dust storm. In this paper, we give an overview of the spatial distribution and chemical properties of heavy metals by collecting deposited particulate matter samples at ten stations from August 2011 to July 2012. The samples were analyzed using inductively coupled plasma for Cd, Co, Fe, Pb, Ni, and V, and using hydride generation for As. Multivariate gap statistical analysis was used to investigate the concentration and source of metals. Based on the comparison between the original data and background levels, geostatistics, disjunctive kriging, and pollution index I POLL techniques were used to quantify their geospatial patterns and assess the contamination levels of the heavy metals. Results of the fitted models with disjunctive kriging technique showed that As and V were fitted to the Gaussian model with a range of 1.95 and 4.74 km, respectively. Fe and Pb were fitted to the exponential model with a range of 1.37 and 1.06 km, Cd was fitted to the spherical model with a range of 4.74 km, Co was fitted to the rational quadratic model with a range of 1.44 km, and Ni was fitted to the circular model with a range of 14.98 km. Agglomerative hierarchical clustering and Gap statistic methods classify the sampling periods in two main groups; dust and non-dust. The results presented a wide range of metal pollution. In the non-dust period, the mean predominant values showed moderate pollution for Ni; while the dust period had extremely severe pollution for As and Ni, and very severe pollution for Fe and V. Overall, the I POLL values in dust periods followed the sequence of As > Ni > V > Fe > Cd > Co > Pb. In the dust period, over 70 % of metals in the deposited particulate matter were from external origins. With exception of Fe, all the metals had weakly spatial dependence, indicating that entry of metals was by dust storm. Monitoring of the source of the deposited particles showed that in the periods of occurrence of dust, the dusts originated from Syria and Iraq, and entered Iran.