What type of soil is typically used to cover landfilled waste?

The correct type of soil typically used to cover landfilled waste is clay. Clay is chosen because it has very low permeability, which helps to minimize the movement of liquids and gases between the landfill and the surrounding environment. This quality is crucial for environmental protection, as it reduces the risk of leachate contaminating groundwater and limits the escape of landfill gases.

Other types of soil, like sandy loam, gravel, or topsoil, do not provide the same level of containment. For example, sandy loam tends to drain easily, which is not suitable for preventing leachate migration. Gravel, while offering good drainage, would also allow gases and liquids to escape more readily, defeating the purpose of capping the landfill. Topsoil, although beneficial for vegetation growth, does not have the necessary properties to act as an effective barrier against liquid and gas migration in a landfill context.

Thus, clay stands out as the most appropriate choice for covering landfilled waste due to its ability to act as a sealing layer, ensuring environmental safety.