*3.2.2 The unified soil classification system*

The Unified Soil Classification System (USCS) established in 1942 is also commonly used in contaminated site environmental investigation. Each type of soil is given a two-letter designation based on its texture, atterberg limit and organic matter content (**Table 6**). Since every soil contains a blend of soil separates, the


#### **Table 6.**

*Tactile and observational clues related to textural classes for USCS and USDA.*

*Surfactants and Their Applications for Remediation of Hydrophobic Organic Contaminants… DOI: http://dx.doi.org/10.5772/intechopen.100596*

possibility of soil that contains only sand or clay is not realistic. For additional information on soil classification by feel, the reader is referred elsewhere [19, 20].
