Analysis on the characteristics of underground gasoline pollutants migration in a certain karst region in Guiyang City

The geological environment in karst area is vulnerable, especially in the shallowly buried karst region, the groundwater there is easily to be polluted. The characteristics of groundwater gasoline pollutants migration is analyzed by studying instance of petrol leakage at a gas station10 years ago in Guiyang City in this article. The results is as follows:(1)Influenced by the lithology, construction, thickness of aeration zone, heterogeneous characters such as ground gradient, groundwater velocity, the gasoline pollutants migrate mainly through karst tube, bedrock surface, fracture, and cracked top strata of the bedrock.(2)The gasoline pollutants migrate and diffuse preferentially through fault, fracture, karst cave, and lateral migration is stronger than the vertical one.(3)Other than migrate with groundwater flow, organic pollutants also disperse apparently in those bedrock uplifted part and high topography part.(4)As red clay has high sorption to pollutants, pollutants mainly contaminate the nearby bedrock, only very few can contaminate the upper part.(5)The gasoline pollutants are buried in karst tube, karst fracture and the contact surface between the soil and the rock which made it quite difficult to migrate and eliminate.