Total Heavy Metal Spatial Patterns in Calcareous and Saline Soils of Khuzestan Alluvial Plain, Southwest of Iran.
Amir H. Charkhabi Sr., Soil Conservation and Watershed Management Research Institute of Iran, Special Road of Karaj, Ashouri St., Tehran, Iran
Assessing the of variability of important chemical parameters such as those of heavy metals in soils is crucial in environmental assessment studies Using geostatistical interpolation techniques appeared to be well suited for most pollution assessment studies. Therefore, these techniques were used in this study for Khuzestan alluvial plain with about 3,000,000 ha in the northwest of Persian Gulf region and southwest of Iran. This province has petroleum and steel related industries and activities and hence the area is exposed to various hazardous materials. More importantly, in the recent three decades due to the regional conflicts and wars a great deal of complexity has been added to the previous state of heavy metals and other hazardous materials into the soils as the main sink of these hazardous matrials. Therefore, spatial patterns of heavy metal distribution using GIS and geostatistical models wwere important and used this in study for environmental assesments . of soil pollutions. Composite soil samples were taken from three depths of 0-5, 10-15, and 40-50 cm at more than 150 sites and analyzed with ICP for total metals contents for some selected heavy metals such as Fe, Mn, Pb, Cu, Ni, Hg, Co and V at ppm level. The results showed kriging was a suitable interpolation method and it was well-fitted for the preparation of DTM maps and spatial pattern for most of these metals. Moreover, digital terrain models of other selected parameters that are important in the interpretation of heavy metal behavior in the soils such pH, ECe, organic carbon content and sums of cations and anions were also prepared in Arc-GIS environment. The spatial patterns of the heavy metals showed complex patterns, however, generally from east to west the concentrations of the metals increased. The concentrations of these metals at the top soils were generally higher than those of subsoils and dereased with depth. The results could help us to find the hot spots with heavy metal accumulation and environmental decision makings at large scale for these mainly alluvial calcareous and saline soils. Key words: Geostatistics, Persian Gulf, digital terrain models, heavy metals, soil parameters, GIS.