Glossary

• A
• B
• C
• D
• E
• F
• G
• H
• I
• J
• K
• L
• M
• N
• O
• P
• Q
• R
• S
• T
• U
• V
• W
• X
• Y
• Z

VADOSE OR UNSATURATED ZONE:

The zone in between land surface and the water table where the soil pores are only partially filled with water. This zone is delineated by the land surface above and by the surface of the saturated zone, that is, the water table below.

VAPOR EXTRACTION TEST:

Field test to measure the efficacy of using vapor extraction as a potential remedial option.

VEHICLE MILES TRAVELED (VMT):

The number of miles driven by vehicles within a given time period and geographic area. It is influenced by several factors, typically increasing with a higher numbers of car trips and distance traveled as well as poorly-planned development. 

VINYL CHLORIDE:

Vinyl chloride is widely used in the plastics industry in creating polyvinyl chloride (PVC).

VOLATILE ORGANIC COMPOUNDS (VOCS):

Organic compounds, including many common solvents, that readily evaporate at normal temperatures and pressures a common contaminant normally found at ground surface and at shallow depths.

VOLATILITY:

 The tendency of a liquid to evaporate. 

VOLATILIZATION:

The process of transfer of a chemical from the aqueous or liquid phase to the gas phase. Solubility, molecular weight, and vapor pressure of the liquid and the nature of the gas-liquid affect the rate of volatilization.

VOLUNTARY CLEANUP PROGRAM:

Established in 1993, it allows DTSC to provide oversight to motivated parties to assess and/or cleanup lower priority sites.  Teamwork is a key component of this streamlined program.