Significance and Use
5.1 The MIP system provides a timely and cost effective way (4) for delineation of volatile organic contaminants (for example, benzene, toluene, solvents, trichloroethylene, tetrachloroethylene) with depth (5, 6). Recent investigation (2) has found the MIP can be effective in locating zones where dense nonaqueous phase liquids (DNAPL) may be present. MIP provides real-time measurement for optimizing selection of sample locations when using a dynamic work plan. By identifying the depth at which a contaminant is located, a more representative sample of soil or water can be collected.
5.2 Correlation of a series of MIP logs across a site can provide 2-D and 3-D definition of the contaminant plume. When lithologic logs are obtained (EC, CPT, etc.) with the MIP data, contaminant migration pathways may be defined.
5.3 The MIP logs provide a detailed record of contaminant distribution in the saturated and unsaturated formations. A proportion of the chlorinated and non-chlorinated volatile organic contaminants in the sorbed, aqueous, or gaseous phases partition through the membrane for detection up hole.
5.4 The data obtained from application of this practice may be used to guide soil (Guide D6282) and groundwater sampling (Guide D6001) or placement of long-term monitoring wells (Guide D6724).
5.5 MIP data can be used to optimize site remediation by knowing the depth distribution of volatile organic contaminants. For example, materials injected for remediation are placed at correct depths in the formation.
5.6 This practice also may be used as a means of evaluating remediation performance. MIP can provide a cost-effective way to monitor the progress of remediation. When properly performed at suitable sites, logging locations can be compared from the initial investigation to the monitoring of the contaminant under remediation conditions.
Scope
1.1 This standard practice describes a method for rapid delineation of volatile organic contaminants (VOC) in the subsurface using a membrane interface probe. Logging with the membrane interface probe is usually performed with direct push equipment.
1.2 This standard practice describes how to obtain a real time vertical log of volatile organic contaminants with depth. The data obtained is indicative of the total volatile organic contaminant concentration in the subsurface at depth.
1.3 Other sensors, such as electrical conductivity, fluorescence detectors, and cone penetration tools may be included to provide additional information. The use of a lithologic logging tool is highly recommended to define hydrostratigraphic conditions, such as migration pathways, and to guide confirmation sampling.
1.4 Limitations—The MIP system does not provide specificity of analytes. This tool is to be used as a total volatile organic contaminant-screening tool. Soil and/or water sampling (Guides D6001, D6282, D6724, and Practice D6725) must be performed to identify specific analytes and exact concentrations. Only VOCs are detected by the MIP system in the subsurface. Detection limits are subject to the selectivity of the gas phase detector applied and characteristics of the formation being penetrated (for example, clay and organic carbon content).
1.5 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without the consideration of a project’s many unique aspects. The word “standard” in the title means that the document has been approved through the ASTM consensus process.
