Effects of long-term agricultural activities on the availability of heavy metals in Syrian soil: A case study in southern Syria

Agricultural soil pollution has attracted the attention of scientists and agricultural managers because of its importance to food security worldwide. In Syria, limited studies have been conducted to determine heavy metals (HMs) concentrations in arable lands. The objective of this study was to investigate the concentration of HMs in the southern part of Syria, and to identify the potential sources HMs. To achieve the study goals, 38 soil samples (0–25 cm) were collected and analysed for physical and chemical soil properties, while the DTPA (Diethylenetriamine pentaacetate) method was to extract HMs from soil.The results of this study showed that the average concentration of HMs in the study area are 2.00; 12.70; 8.56; 4.37; 0.12; and 0.12 ppm for Cu; Fe; Mn; Zn; Cd; and Pb, respectively. A multivariate statistical analysis showed that Cu, Fe, and Mn originated from parent material (natural resources), while Zn and Cd were related to agricultural activities (anthropogenic one) and Pb was relatively related to industrial activities. Interestingly, the spatial distribution indicates that Cu, Fe, and Mn distributed in the southern and eastern part of the study area, while Pb and Zn were dominant in the western and northern part. In addition, Cd was observed in the central part of the study area. We conclude that human activities are the main contributor of HMs accumulation in soil. The distribution of these HMs could affect the safety of agricultural product in the future.