Environmental Impact Assessment of Trace Metal Deposition Around the Petrol Filling Stations

Abstract

The wide use of petroleum products causes contamination of air, water, soil and plants. The present study was conducted to monitor the trace metal deposition in road side soil around the petrol filling stations along the busy roads of Karachi, Pakistan. Total 21 road side soil samples were collected from selected locations of busy roads. The soil samples were digested using acid digestion method and atomic absorption spectrophotometer (AAS) was used for the elemental analysis. Results of the study showed that concentration of lead was highest in the soil samples ranging from 41.3 to 361 mg/kg, then copper from 23.0 to 101 mg/kg, manganese from 36.2 to 125.0 mg/kg and zinc from 27.5 to 213.0 mg/kg, respectively. The correlation-coefficient (r) was also calculated between the metals in soil samples. The correlation matrix showed that all the pollution is coming from the same source. The gravitational sedimentation and impact on vegetation of coarse fraction is responsible for the high lead contamination of vegetation and soils. Collected data showed that, almost all the pollution being generated by automobile exhaust in urban areas of Karachi. The soil acts as an important sink for pollutants released through different activities.