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

Abstract

of roads runoff pollutants (4). Pollutants transferred with road runoff are divided into suspended solids, heavy metals, biodegradable organic matters, organic micro-pollutants, pathogenic organisms, nutrients and petroleum products (5). Without treatment, these components may find their way directly into surface water or penetrate into the soil of the roadside (1). Since organic pollutants are associated with particles and sediments, they are possibly more serious during Journal of Human, Environment and Health Promotion Journal homepage: www.zums.ac.ir/jhehp 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.