Spatial Distribution of Lead in the Soil of Urban Areas Under Different Land-Use Types

Awareness of lead (Pb) distribution and zoning in urban, agricultural, and industrial areas is of particular importance in environmental protection planning. This cross-sectional study aimed to determine the distribution of Pb in different uses with different levels of industrial development and human activities in urban areas in Hamadan during 2018. For this purpose, 146 soil samples were collected from 0-20 cm depth and prepared for air-dried laboratory analyses. Then, pH, electrical conductivity (EC), total Pb, and adsorbable Pb in the soil were measured. The results demonstrated that the mean concentration of total Pb is 88 mg/kg. In addition, the mean concentration of Pb in urban, industrial, and agricultural areas was 41 mg/kg, 30 mg/kg, and 17 mg/kg, respectively. Further, the average concentration of adsorbable Pb with a standard deviation of 0.3 in industrial, urban, and agricultural areas was 0.38 mg/kg, 0.16 mg/kg, and 0.06 mg/kg. Land use was an important source of Pb change in the studied soils; however, Pb change did not depend only on land use. Factors such as weather conditions or proximity to roads, as well as previous land uses, could affect the role of existing land use and be effective in the distribution of soil Pb. Studies revealed that the amount of the soil’s adsorbable Pb is more important than that of total Pb in different uses, which should be considered in any soil-related research.