| Use: | More commonly used for well purging than ground water sampling. |
Description:
Gas-driven displacement pumps can sample at a continuous rate or a discrete depth; however, this method is more commonly used for purging rather than sampling. Positive gas pressure applied to the surface of water within the sample chamber forces the sample to the surface through an open tube. Gas-driven displacement pumps can be installed permanently in uncased boreholes, and multiple installations in a single borehole are possible.
Analytes:
| 1. Non-Halogenated VOCs | 5. PAHs | 9. Inorganics |
| 2. Non-Halogenated SVOCs | 6. Pesticides/Herbicides | 10. Explosives |
| 3. Halogenated VOCs | 7. Metals | 11. TPHs |
| 4. Halogenated SVOCs | 8. Radionuclides |
Media:
| Soil: | Ground Water: | Surface Water: | Gas/Air: |
| Not Applicable | MINIMUM | MINIMUM | Not Applicable |
Gas-driven pumps deliver samples at a controlled, nearly continuous flow rate. Use of inert driving gas minimizes sample oxidation and other sample chemical alteration. However, they may not be appropriate for chemically-sensitive parameters if air is used as the driving gas due to potential oxidation of metals or gas stripping of VOCs.
| Maximum Depth: | Up to 100 feet. Deep sampling locations require an air compressor or large compressed air tanks. Minimum well diameter: 1 inch. |
| Production Rate: | Sample is available after a short amount of time. 0.1 to 10 gallons per minute. |
| Investigation Derived Waste Volume: | Medium volume of waste. |
| Technology Status: | Commercially available and routinely used field technology. |
| Certification/Verification: | Technology has not participated in CalEPA certification and/or CSCT verification program. |
| Relative Cost per Sample: | Least expensive. |
Limitations:
ASTM Standards:
| D 4448 - 85a | Sampling Ground Water Monitoring Wells. |
| D 6232 | Standard Guide for Selection of Sampling Equipment for Waste and Contaminated Media Data Collection Activities. |
| Previous Page | Sample Access/Collection Matrix | Sample Analysis Matrix | Home | Areas of Interest | Next Page |