Spills of oil or chemicals should be reported immediately to the National Response Center or Virginia Emergency Response Council. See Resource Directory for appropriate contacts. Therefore, evaluating the site properties is an important step in protecting groundwater and the quality of water supplies. A. Soil Type Soil characteristics are very important in determining whether a contaminant breaks down to harmless compounds or pollutes the groundwater. Because most breakdown occurs in the soil, there is a greater potential for groundwater contamination in areas where contaminants can move quickly through the soil.
Sandy soils have large pore spaces between individual particles.
Large amounts of rainfall can percolate through these soils and dissolved contaminants can move rapidly down through the soil and into groundwater. Clayey soils, on the other hand, are made up of extremely small particles that slow the movement of water and dissolved contaminants through the soil. Some contaminants, such as phosphorus, also may adhere or stick to clay surfaces and not reach the groundwater table. Soil organic matter content is important in holding contaminants. Soils high in organic matter provide an excellent environment for chemical and biological breakdown of many contaminants before they reach groundwater.