Final Decision to Certify Hazardous Waste Environmental Technology
PCB RaPID Assay™ for PCB's in Soil and Water
Certification No: 94-01-006
The technology is an enzyme immunoassay for the fast, semiquantitative field measurement of polychlorinated biphenyls (PCBs as Aroclors) in soil or water. The antibody is bound to magnetic particles. The reaction is performed either on a small water sample which is immediately mixed with an equal amount of methanol or an extract prepared by dispersing and shaking a small weighed or volumetric soil sample in a small volume of methanol which contains a dispersant. After reagent additions and separation of the mixture from the magnetic particles, a color reaction occurs which is read in a photometer as a numerical result representing the sample concentration in a range from 0.2 to 10 ppb in water or 0.5 to 10 ppm in soil, respectively (as Aroclor 1254). Higher concentrations are estimated by selecting a target concentration (usually a regulatory or action level) and diluting the methanol-containing sample or extract with a diluent (provided) so that a sample at the target concentration would give a mid-range color reaction in the photometer. The method contains no built-in bias to reduce the probability of false negative results; the user can increase the certainty associated with readings about the target level with the help of tables and other instructions provided by the manufacturer.
The assay is most sensitive to Aroclors 1248, 1254 and 1260; it is somewhat less sensitive to Aroclors 1242 and 1262 and much less responsive to the other Aroclors. The quantification of unknown and weathered Aroclor mixtures requires comparison of the assay results with those obtained by a laboratory method. High moisture content or petroleum hydrocarbon contamination of soils at levels between 1,000 and 10,000 ppm interfere with the method. The nature of the reagents requires the user to avoid temperature extremes during transport and use. Although the method has been tested for a number of possible interferences, results should be confirmed by a approved laboratory method (U.S. EPA SW-846 Methods 8080 or 8081).
Recommended use of this type of assay is in preliminary site investigations where compelling historical data indicate the use of PCBs. In site investigations, the assays allow users to improve the mapping of PCB-polluted areas by a judicious combination of assay results with laboratory results. In remedial actions, progress can be estimated through on-the-spot testing.
Details of the Department's evaluation are contained in the Notice of Certification and in an Evaluation Report.
A copy of the published Certification Notice may be obtained by contacting us at:
File last updated: October 9, 1996