Final Decision to Certify Hazardous Waste Environmental Technology
PCB D TECH® Assay (PCB's in Soil)
Certification No: 95-01-009
The technology is an enzyme immunoassay for fast, semi-quantitative field measurements of polychlorinated biphenyls (PCBs, as Aroclors) in soil. The reaction is performed on a methanol extract of a volumetric (or optionally weighed sample of the soil. The D TECH system offers one or more semi-quantitative detection levels which can be customized for each project. The minimum detection level is 0.5 ppm Aroclor 1254, using a color chart. The confidence level of distinguishing these Aroclor 1254 levels from zero is about 96%; 97% of samples of 0.25 ppm or lower will give a reading of zero. Manufacturer defines"detection" in terms of a minimum reflectometer response particular to this testing system. The reflectometer gives numerical readings; the color chart gives readings of <0.5, 0.5 to 1.0, 1.0 to 4.0, 4 to 15, 15 to 25, and >25 ppm. With the reflectometer, the measurement range is extended to 50 ppm. In addition, higher testing ranges can be selected by placing a target concentration into the midrange of the method and diluting the sample extract accordingly. The manufacturer provides testing reagents and utensils, a color chart, a reflectometer for field or laboratory use (optional), diluent/buffer solution (optional) for measurements at higher concentrations, user manual, material safety data sheets, and instruction in the use of the testing system.
Due to the design of the antibody, the assay responds differently to various Aroclors. It responds equally well to Aroclors 1254, 1260, and 1262; the response to Aroclors 1248 and 1260 is lower by less than a factor of two. Responses which are lower by factors between 2 and 10 apply to Aroclors 1016, 1232, 1242, and 1268. The assay responds poorly to Aroclor 1221. For unknown PCB mixtures, analyses by a reference method (U.S. EPA SW-846 Methods 8080 or 8081) can be used to calibrate the system. The same approach can help with weathered PCBs, but the user must remain aware of variability within each study site. Very high moisture content (over 35%) and oily contaminants cause poor recoveries or interference.
As with other immunoassays, the user must be trained in its use and be aware of shelf life of the biological reagents and their sensitivity against extreme temperatures.
A copy of the published Certification Notice may be obtained by contacting us at:
File last updated: October 9, 1996