ABSTRACT
The Orontes river basin can be considered one of the most polluted areas in the eastern Mediterranean due to the intense urban occupation, intensive agriculture irrigation, and large numbers of different industries activities. The objective of the study was to assess the extent and severity of heavy metal pollution of arable soils of Hama floodplain, in order to provide a general insight vision of pollution status in this intensive agricultural production area. The present and spatial distribution of four heavy metals (Cd, Cu, Pb, Zn) concentration have been examined in 5 monitoring sites of river’s water along the part of the river passing through the plain of Hama; and also from 93 samples of topsoil from the area surrounding the city of Hama have been examined. The concentrations of heavy metals in both river water and soil were within the international standards. Water analyses indicated pH of moderately alkaline, no irrigation problem related to ammonium nitrogen and phosphate phosphorus, while the Electrical Conductivity (EC) has referred to an increasing problem. Geo-accumulation Index (Igeo) refers to strong building up for Cd, Pb, and very strongly for Cu. Soil analyses refer to clayey, calcareous, and alkaline soil with pH ranges from 7.5 to 8.6, with significantly higher organic matter content especially near sewage plants, attributed to irrigation with untreated sewage sludge water. Geostatistical analysis of data showed up normal spatial distribution related to the high variation between the values of the studied elements; whereas the Cu and Cd concentrations were higher than allowable limit near the steel, rubber wheel factories and reach 127 for Cu and 9.8 μg·g-1 for Cd. Additionally, a high concentration of Cu was significantly associated with organic matter content. The concentration of Pb was within the limits, with the exception of riverbanks where the values of Pb exceed 95 μg·g-1, with (Igeo) of 4.22 refers strongly to very strong accumulation. Total Zn concentration showed higher variability and values ranging from 13 to 760 μg·g-1, with a distribution trend increases from southeast to northwest. However, its environmental risk will be more serious to human and livestock.