The Effect of Paved Roads on Organic Carbon Content of Soil in Taham Dam Basin

Background; Contamination of water and soil through non-point sources such as road runoff causes environmental concern. The aim of this study is to determine the effect of Zanjan – Chavarzagh road on the total organic carbon (TOC) content of sediments in tributaries and the river that lead to Taham Lake. Methods; In tributaries and the river 69 soil and sediment samples were taken and the Total organic carbon (TOC) was measured according to Walkely-Black method. Also, Taham Dam Basin area and its hydrologic properties were calculated by Global Information System (GIS) software. Results; Results showed that, TOC concentration has a significant negative relationship with the distance from the lake. TOC in soil samples taken from hillside of the road had significantly lower mean and median concentration ( median= 3262 , mean = 4083 ± 3461  mg/kg) than the valley side ( median = 5324 , mean = 6178 ± 3980  mg/kg). The check dams across the tributaries and the river have not been effective in the reduction of TOC in sediments. Conclusion; Roads in the Taham Dam Basin, increases TOC content of soil and sediments in Taham dam basin. TOC moves toward Taham dam lake.