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Final Decision to Certify Hazardous Waste Environmental Technology


Ohmicron Environmental Diagnostics, Inc.

The Ohmicron RaPID Assay® System for Pentachlorophenol (PCP)


CALIFORNIA REGULATORY NOTICE REGISTER
Published Weekly by the Office of Administrative Law
Register 95, No. 5-Z
February 3, 1995
pp 212-215


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

Ohmicron Environmental Diagnostics, Inc.
375 Pheasant Run
Newtown, PA 18940

The Ohmicron RaPID Assay® System
for pentachlorophenol (PCP) using
enzyme-linked immunosorbent assay
(ELISA)

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

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

The DTSC 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 DTSC'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 DTSC as required by the statute under which certification is granted.

The DTSC's proposed decision to certify has been previously noticed on December 23, 1994, in the California Regulatory Notice Register 94, Volume No. 51-Z, pp. 1976-1979. 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 DTSC's final certification shall be effective on Monday, March 6, 1995.

Additional information supporting the DTSC'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:

Ohmicron Environmental Diagnostics, Inc.
The Ohmicron RaPID Assay® System
for pentachlorophenol (PCP)

Certification Statement and Technology Specifications

Under the authority of Section 25200.1.5 of the California Health and Safety Code, the Department hereby certifies the PCP RaPID Assay® (Pentachlorophenol in Water and Soil) manufactured by Ohmicron Environmental Diagnostics, Inc. as a Measurement Technology. The Ohmicron RaPID Assay® System for pentachlorophenol (PCP) uses enzyme-linked immunosorbent assay (ELISA) technology. It differs from other systems in that polyclonal antibodies are supplied attached to magnetic particles. PCP in water is assayed directly; for soils, the system uses extraction with alkaline methanol. The immunoassay system is semi-quantitative. Provided that the materials are used properly, detection is possible at 0.06 to 10 ppb in water and 0.1 to 10 ppm in soil; ranges can be extended upward by dilution of the extracts.

Quantitative readings about a selected target level are obtained in a microprocessor-equipped, hand-held, battery-operated photometer or a compact table top photometer supplied by the manufacturer, or a standard laboratory photometer. The calibration is not biased, but the user is instructed to select target levels so as to determine the degree of confidence in avoiding false negative results. The reaction with other chlorophenols is insignificant except for 2,3,5,6- and 2,3,4,6-tetrachlorophenol and some trichlorophenols (some of these are contaminants in technical grade PCP). Creosote may interfere at levels over 100 ppm; diesel fuel and other solvents for PCP may interfere when present at levels of 2 to 10 percent. Differences in the extraction efficiency of PCP from various soils may cause positive or negative errors in the immunoassay results. Users should evaluate these factors before attempting to quantify results.

Limitations of Certification

DTSC 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 DTSC 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.

DTSC 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.

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 DTSC as required by the law under which this Certification is granted.

Specific Conditions

  1. Differences in the extraction efficiency of PCP from various soils can cause positive or negative errors in the immunoassay results. Users should evaluate these factors before attempting to quantify results. Users should be encouraged to prepare soil matrix spikes and vary extraction times to establish local soil extraction efficiency and to evaluate interferences (matrix effects). We recommend that pentachlorophenol-spiked soil samples be allowed to age for a two-week period for a more representative evaluation of extraction efficiencies.
  2. Although precision of the assay is acceptable, in view of the above users should be discouraged to report results with no more than two significant figures unless this is specifically required in a quality assurance project plan to facilitate statistical treatment of the data.

Basis for Certification

The Documentation submitted by the manufacturer and other studies are listed in the evaluation report on which this certification is based. The manufacturer has asserted that certain materials contain proprietary information and therefore should not be subject to public disclosure.

Recommended Applications

The assay was developed for the semiquantitative determination of PCP. 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 (such a regulatory action or cleanup level).

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 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 (confirmation and quantification, i.e., EPA Methods 8040, 8250 or 8270A) applied predominantly to positive results. We recommend that minimum quality control should include a method blank and duplicates at 10 to 20 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.

U.S. EPA SW-846 Methods 8040 (GC), 8250, and 8270A (packed and capillary column GC/MS) are available and currently approved for establishing or confirming concentrations of PCP.

"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 PCP (such as in wood treatment operations). If used on samples with unknown potential for analytical interferences and matrix effects, confirmatory analysis is needed for every positive immunoassay result. The user should be aware of the reactions given by tetrachlorophenols, common contaminants of commercial preparations of PCP. No negative determinations can be made without taking into account the specificity of the assay and its possible susceptibility to interferences and matrix effects. In the absence of other regulations and guidelines, we recommend that assay results be confirmed in the following manner:

(a) For the delineation of PCP 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) Ten to twenty percent of results which are above the detection level but 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) Five to ten percent 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 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

DTSC's Certification is based on the technology's performance and by itself does not change the regulatory status of pentachlorophenol 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 DTSC's findings should contribute to a consideration of this technology in regulated activities, depending on each regulated program's objectives and constraints. State-regulated disposal facilities may contact state permitting officers for use of the immunoassay for operational monitoring. Other local and state government permitting authorities may take this certification under consideration when making their permitting decisions. Other project leaders may consider using this assay if a project's data quality objectives can be met by its use.


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
e-mail: techdev@dtsc.ca.gov


File last updated: October 9, 1996


 
 
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