| Use: | Collection of soil pore liquids in the vadose zone. |
Description:
Sorbent methods utilize a porous material to absorb soil pore water:
| Cellulose nylon sponge: | Sponge is placed with a trough, which is positioned against the ceiling of a horizontal tunnel by a series of three lever hinges. When the sponge has absorbed a certain volume of pore water, the trough is withdrawn, and the sponge is placed in a moisture tight container. |
| Ceramic rods: | Tapered ceramic rods or points are weighed before being driven into the soil. When they are withdrawn, the rods are again weighed to determine volume of absorbed water. Boiling them in a known volume of distilled water leaches the points. The solution is analyzed and the original pore water concentration determined from the ratio of water absorbed by the ceramic to the volume of boiling water. |
SEAMIST™ is an instrumentation and fluid sampler emplacement technique designed for in-situ characterization and monitoring. It uses an inverting, pneumatically deployed tubular membrane made of impermeable material to deploy sensors and/or samplers in boreholes or to tow instruments downhole in a clean, stable borehole environment. The membrane, made of coated fabric or synthetic film, is forced from a holding canister by air pressure into a drilled or punched well. The membrane descends, averts, and presses against the hole wall, providing wall support and the effect of a continuous packer. After emplacement, the entire hole wall is sealed, thus preventing ventilation of the pore space or circulation of pore water in the well. The membrane is retrievable or, if desired, permanent installation is possible by filling the membrane with grout after emplacement. Semi-permanent installation can also be accomplished by filling the membrane with sand after emplacement, which can be removed by vacuuming where membrane retrieval is desired.
A variety of sensors and/or sampler instruments can be integrated with the SEAMIST™ deployment system. The membrane can be used to perform vadose zone pore and fracture fluid sampling using absorbent pads. Electrical resistance measurements inside the pads indicate moisture uptake. By attaching an array of absorbent pads to the membrane, high spatial resolution of the contaminant distribution is 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 | MINIMUM |
| Maximum Depth: | Not Applicable. |
| Production Rate: | Sample is available after a short amount of time. |
| Investigation Derived Waste Volume: | Small 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 4696 - 92 | Pore-Liquid Sampling from the Vadose Zone. |
EPA Guidance:
| EPA 600/8-87/036 | Soil Gas Sensors for Detection and Mapping of Volatile Organics. |
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