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Strategic Diagnostics, Inc.-PCB D TECH Assay-(PCBs in Soil)

Final Decision to Certify Hazardous Waste Environmental Technology

Published Weekly by the Office of Administrative Law
Register 95, No. 4-Z
January 27, 1995
pp 174-177

The California Environmental Protection Agency, Department of Toxic Substances Control (Department) has made a final decision to certify the following company’s hazardous waste environmental technology listed below:

Strategic Diagnostics, Inc.
Newark, Delaware 19713

(PCBs in Soil)

Chapter 412, Section 25200.1.5., Health and Safety Code, enacted by Assembly Bill 2060 (AB 2060), Weggeland, 1993, authorizes the Department to certify hazardous waste environmental technologies.

The purpose of the certification program is to provide an in-depth, independent review of technologies at the manufacturer’s level to facilitate regulatory and end-user acceptance and to promote and foster growth of California’s environmental technology industry.

The Department makes no express or implied warranties as to the performance of the manufacturer’s product or equipment. The end-user is solely responsible for complying with the applicable federal, state, and local regulatory requirements. Certification does not limit the Department’s authority to require additional measures for protection of public health and the environment.

By accepting certification, the manufacturer assumes, for the duration of certification, responsibility for maintaining the quality of the manufactured equipment and materials at a level equal to or better than was provided to obtain certification and agrees to be subject to quality monitoring by the Department as required by the statute under which certification is granted.

The Department’s proposed decision to certify has been previously noticed on December 9, 1994, in the California Regulatory Notice Register 94, Volume No. 49-Z, pp. 1911-14. Written comments in relation to the proposed certification received during the public review and comment period have been duly considered in the final certification as presented here. The Department’s final certification shall be effective on Monday, February 27, 1995.

Additional information supporting the Department’s final certification decisions is available for review at:

California Environmental Protection Agency
Department of Toxic Substances Control
Office of Pollution Prevention and Technology Development
P.O. Box 806
301 Capitol Mall, 1st Floor
Sacramento, California 95812-0806
(916) 322-3670

A description of the technology to be certified, the final certification statement and the certification limitations for the technology follows:

Strategic Diagnostics, Inc.
(PCBs in Soil)

Technology Description

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 weighed or volumetric sample of the soil. The DTECH system offers one or more semi-quantitative detection levels which can be customized for each project. The minimum detection level is 0.5 ppm Aroclors 1254 and 1262 (using the reflectometer) or 1 ppm using the color chart. The confidence level of distinguishing these Aroclor 1254 levels from zero is about 99%; 97% of samples of 0.25 ppm or lower will give a reading of zero. “Detection” is defined by the manufacturer in terms of a reflectometric response particular to this testing system. The reflectometer gives numerical readings; the color chart gives readings of 25 ppm. The upper testing limit with use of the reflectometer is 50 ppm. Testing ranges at higher concentrations can be selected through appropriate dilution of the sample extract. As with other immunoassays, this is done by selecting a target concentration (usually an action level or regulatory limit) and diluting the extract so that the target level is situated at the midpoint of the testing range. The manufacturer provides testing reagents, utensils, a diluent-buffer to extend the testing range, and a reflectometer for field or laboratory use, a 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 equally well to Aroclors 1254, and 1262 and only slightly less to Aroclors 1248 and 1260. Responses to Aroclors 1016, 1232, 1242, and 1268 are lower by factors between 2 and 10. 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.

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.

Certification Statement

Under the authority of Section 25200.1.5 of the California Health and Safety Code, the Department hereby certifies the PCB D TECH™ Assay (PCBs in Soil) manufactured by Strategic Diagnostics, Inc., Newark, Delaware 19713 and marketed by EM SCIENCE, Gibbstown, New Jersey 08027 as a Measurement Technology. The test kit consists of a semi-quantitative immunoassay system for the detection of PCBs, as Aroclors. Provided that the immunoassay is used properly, the minimum detection level of Aroclors 1254 and 1262 is at 0.5 or 1 ppm levels, depending on the method of indication. For most other Aroclors, higher target levels apply. The technology is applicable to testing of soil or soil-like material which is not highly contaminated with oil or other nonaqueous phase liquids (NAPLs). The efficiency of the test depends on the extraction of PCBs from the test soil into a methanol solution. The efficiency of extraction is reduced in excessively moist soils and may be affected by high clay or organic content of the soil. Volumetric sampling of soil as suggested by the manufacturer (sample size appx. 4.5 grams) will usually provide consistent results within one site, but users should be aware of small-scale variability of PCB concentrations in soil and may elect to dry and weigh soil samples collected in parallel for a closer correlation with results of confirmatory analyses. Other limitations are set forth below. The Department’s findings are described in greater detail in an evaluation report.

Limitations of Certification

The Department makes no express or implied warranties as to the performance of the manufacturer’s product or equipment. The Department has not conducted any bench or field tests to confirm the manufacturer’s performance data. Nor does the Department warrant that the manufacturer’s product or equipment is free from any defects in workmanship or material caused by negligence, misuse, accident, or other causes.

The Department believes, however, that the manufacturer’s product or equipment can achieve performance levels set out in this Certification. Said belief is based on a review of the data submitted by the manufacturer and other information, and is based on the use of the product in accordance with the manufacturer’s specifications.

Specific Conditions

  1. The manufacturer shall inform the user that the detectable concentrations apply to a specified Aroclor (Aroclor 1254), that the sensitivity of the assay to the various Aroclors does vary, and that it is important for the user to know what type of Aroclor is being tested and the general range of error if there is a different Aroclor, or a mixture of Aroclors, or if the Aroclors are weathered.
  2. The manufacturer shall keep users abreast of known interferences and matrix effects. As a minimum, users should know that the assay is not suitable for oily matrices and soils containing 1 to 10% or higher levels of petroleum hydrocarbons; also organic solvents may affect recovery. User should be aware of unacceptably low extraction efficiency in wet soils (water content of 35% or higher).
  3. User’s Guide (Ref. 2) shall state under “Important Notice” that the manufacturer recommends that the user be trained in the use of the assay by a qualified trainer or an experienced user.
  4. The User Guide shall contain a clear indication of the shelf life of the reagents and a warning on the deterioration of reagents at high temperatures as may be encountered in transit and in field use.

Basis for Certification

  1. Application for Environmental Technology Certification, Strategic Diagnostics, Inc., 1 February 1994;
  2. Updated Submission package for Environmental Technology Certification, EM Science/Strategic Diagnostics, Inc., 14 March 1994;
  3. “Method 4020: Soil Screening for Polychlorinated Biphenyls (PCB) by Immunoassay.” 2 March 1994. (proposed version by Strategic Diagnostics, Inc., see also Ref. 7);
  4. D TECH™ PCB Submission Package, as submitted to U.S. EPA Office of Solid Waste, EM Science/Strategic Diagnostics, Inc. March 1994;
  5. PCB Test Kit Instruction Guide. EM Science/Strategic Diagnostics, Inc., undated;
  6. PCB Soil Extraction Pac Instruction Guide. EM Science/Strategic Diagnostics, Inc., undated;
  7. “Method 4020: Soil Screening for Polychlorinated Biphenyls (PCB) by Immunoassay.” U.S. EPA Office of Solid Waste SW-846 Revision WG 1, July 1994. This revision names the SDI immunoassay among the acceptable testing systems for the method.

Recommended Applications of the Test System

The immunoassay is for the semiquantitative determination of PCBs in terms of commercial mixtures of PCBs (Aroclor 1248) that has been used in the design and calibration of the assay. Conversion factors are applied to the results for Aroclors to which the assay responds differently. Unknown PCB mixtures need to be characterized by a reference method and a conversion factor needs to be determined which reflects the immunoassay response of that mixture relative to the response of Aroclor 1248. Without such an adjustment, results can be either high or low, depending on the affinity for the assay’s antibodies of an unknown PCB mixture. A semiquantitative determination will provide a response, interpreted as either positive or negative, at one or several predetermined detection or target levels. Target levels are usually chosen to have relevance to a specific situation.

A comprehensive process of developing data quality objectives (DQO) was published by U.S. EPA under the U.S. Superfund Program. It provides guidance for analytical method QA/QC as applied to field investigations for PCB-contaminated soils. The process is intended for site-specific sampling plans. Here the immunoassay would generally qualify as a Level 2 (field analysis) method, subject to confirmation by a Level 3 method (identification and quantification, i.e., EPA Methods 8080 or 8081) applied predominantly to positive results. We recommend that minimum quality control should include method blanks and duplicates at 5 percent, or one per batch or per matrix, whichever is the more frequent, in addition to the samples required for confirmation. The use of proficiency evaluation and spiked samples should depend on project-specific needs.

We recommend gas-chromatographic U.S. EPA Methods 8080 or 8081 for establishing or confirming the types and concentrations of Aroclor(s).

“Screening” and Preliminary Site Investigations-The immunoassay can assist in preliminary site investigations (“Phase I”), if there are compelling historical data to indicate the presence of PCBs. If used on samples of largely unknown composition, without prior characterization by an approved, fully quantitative and qualitative laboratory method, confirmatory analysis is needed for every positive immunoassay result. No negative determination can be made without taking into account the specificity of the assay and its possible susceptibility to interferences and matrix effects. A margin of error (above the state detection level) should be allowed for those PCBs that may show a lower response than those for which the assay has been calibrated.

In the absence of other regulations and guidelines, we recommend that assay results be confirmed in the following manner:

(a) For the delineation of PCB contamination in a coherent mass of soil, the required frequency of confirmation by an approved method resulting in identification and quantification is at least 10 percent of the samples testing positive at the target or action level applicable at the site. In the event that fewer than ten samples meet these criteria, at least one positive sample shall be confirmed. Higher rates of confirmation apply if there is a potential for chemical interferences.

(b) 10 to 20 percent of positive results below the target or action level should be confirmed by an approved, fully quantitative method, except that a higher rate of confirmation may be necessary if the results are to be used in health risk assessments.

(c) 5 to 10% of all negative results, but no less than one result from each site or suspect area, should be confirmed.

If appropriate protocols are followed, the immunoassay can be used to great advantage to classify contaminated soils as to low, medium, or high contamination and to determine which samples would provide the most information from laboratory analysis.

Site Investigations and Remedial Actions-Here the testing is expected to proceed under a site-specific Quality Assurance Project Plan (QAPP). Immunoassay and other field measurements will be “bracketed” in time and space by qualitative and fully quantitative analyses. Generally, a site is first characterized by the use of approved, fully qualitative and quantitative analytical methods as to the nature and level of contamination in key sampling locations and as to the presence of substances that may interfere with the use of the immunoassay. After such initial characterization, the immunoassay can be used in the comprehensive mapping of the site with respect to identified contaminant(s) to which the immunoassay responds. The percentage of samples that would be confirmed by another approved, fully quantitative method would be as stipulated in the QAPP; the project manager could call for additional confirmatory testing if such a need is indicated in the course of the investigation. During site cleanup, the QAPP would provide for use of the immunoassay to monitor progress. Confirmatory laboratory testing would occur before a decision on site closure is made.

Regulatory Implications

This immunoassay has been accepted as a Draft Method by the U.S. EPA Office of Solid Waste (SW-846 Collection of Methods, Method 4020, Revision WG 1, July 1994). The Department’s Certification is based on the technology’s performance and by itself does not change the regulatory status of PCB testing; it should, however, facilitate and encourage the acceptance of this technology where a project’s data quality objectives can be met by its use. To this end, the Department’s findings should contribute to a consideration of this technology in regulated activities, depending on each regulated program’s objectives and constraints.

State certification does not imply certification by the U.S. Government for the use at federal superfund sites and other facilities under the jurisdiction of the U.S. Government for which state authorization for administrative oversight has not been granted. Under state implementation of the U.S. Resource Conservation and Recovery Act (RCRA), Treatment, Storage, and Disposal Facilities may contact state permitting agencies for use of the immunoassay for operational monitoring as part of a Waste Analysis Plan (WAP).

This Certification is issued as part of a pilot project to expedite the California Environmental Technology Certification Program. As a result, this Certification is subject to the conditions set out in the regulations to-be-developed, such as the duration of the Certification, the continued monitoring and oversight requirements, and the procedures for certification amendments, including decertification.

By accepting this Certification, the manufacturer assumes, for the duration of the Certification, responsibility for maintaining the quality of the manufactured materials and equipment at a level equal or better than was provided to obtain this Certification and agrees to be subject to quality monitoring by the Department as required by the law under which this Certification is granted.

For more information, contact us at:

Department of Toxic Substances Control
Office of Pollution Prevention and Technology Development
P.O. Box 806
Sacramento, California 95812-0806
Phone: (916) 322-3670
Fax: (916) 327-4494

File last updated: October 9, 1996