GAC (granulated activated carbon) | A highly porous form of carbon with very even and large pore volume, often made from coconut shells. The high porous structure of activated carbon provides a very large surface area for absorption. |
gas chromatography | A laboratory technique to identify organic compounds by detecting the rate at which they pass through a column. This technique is often used to separate compounds and used in conjunction with mass spectroscopy. |
ground-penetrating radar (GPR) | A technology that emits pulses of electromagnetic energy into the ground. It measures the reflection and refraction by subsurface layers and other features, such as buried debris. |
groundwater | The water in the area of the subsurface that is saturated. That is, the pores between such materials as sand, soil, or gravel are filled with water. |
grout | A mixture of water and cement used in sealing wells and to retard water flow. |