dei>elopingand implementing a nationwide qiralitj. assurance prograni f o r the m e a ~irrenientof air pollutants both in ambient air arid in soiirces of eniissions. I n addition. E M S L I K T P condircts .specialized field nionitoring and analj,tical progranis to gather inforniation in support o f dereloping air polllition strategies, estahlishing regulations, supporting health e f fect stirdies, andlor nieasuring toxic suhstances. For the past 24 j3ears,Dr. Hauser has been eniploj,ed in the Federal Air Pollirtion Control Program and has p u b lished nunierous technical articles concerned with the d e w l o p e n t and eraluation o f analj’tical niethodologji f o r the analj,.si.s ofnir pollutants as well as rerieE, papers on E P 4 nionitoring articitie.s.
Part I1 Dwight G. Ballinger Encirotinirnral Monitoring and Support Laborator! -Cincinnati Cincinnati. Ohio 45268 Within the life span of most readers of this article, there has been a fundamental change in the philosophy of water pollution control. Forty years ago, the basic principle of waste treatment was the protection of the receiving surface stream against aesthetic and environmental assault. Treatment technology was based on removal of suspended solids, reduction of the oxygen demand of the waste, removal of nutrient materials, and elimination of disease-producing orga n i s ni s . Measurements on the efficiency of treatment were in pounds of biochemical oxygen demand (BOD) removed, final concentration of nitrogen and phosphorus compounds, removal of oil and grease. and an acceptable level of suspended niaterial. T h e impact on the downstream surface water was determined bj, measurement of dissolved oxygen, the presence or absence of sludge beds. the numbers of indicator bacteria, and the nature of the biota surviving the waste disc h a rge . Short11 after World War I [ , there was an aaareness that discharge of waste. particularly from industrial est a bI ish ni e n t s. represented a ha 7.8rd not onl), to the water quality of the receiving stream but to human health as well. The widespread manufacture and use of synthetic pesticides may have been the first alert to these dangers. Rapid expansion of the use of synthetic chemicals. with associated waste products. brought a concern for 1362
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the effect of these materials on people who came in contact with contaminated water, especially those whose water supply was drawn from polluted sources. Identification of contamination no longer depended on sight and smell, since these new pollutants seldom effected the aesthetic properties of the stream or lake. The Clean Water Act of 1972 was the first major federal attempt to identify and control the discharge of toxic substances. Sections 307 and 3 1 1 of the Act required the establishment of acceptable discharge levels for toxic compounds and the monitoring of discharges of these materials. Along with recognition of the importance of Lsaste discharges on human health, came 9 new awareness of the importance of the data upon which to judge the acceptability of treatment. While the traditional BOD could be reported in pounds per daq of the waste, the toxic compounds had to be measured in micrograms per liter ( F ~ / L ) Where . previously an error in measurement of 20 mg/ L of suspended solids was acceptable, two orders of magnitude less of a carcinogen n.ould not be good enough. It was readily apparent that quality assurance (QA) to measure and establish the reliability of water monitoring data was essential. The Clean Water Act established a regulatory climate more intensive than any previous federal or state legislation. The United States Environmental Protection Agency (EPA) is a regulator and its enforcement actions often result in litigation. These proceedings involve conflicting testimony on the sources. significance. transport. and e n vi ro n m e n t a I i m pact of po I I ut a n t s . In man) cases, laboratory data on the concentration of specific toxic substances is crucial to a fair assignment of responsibility for origin and control. Q A of all data submitted for the record is essential to a proper resolution of the case. A well-documented Q A system. submitted with the laboratory results, significantly strengthens the use of the information. The Analytical Quality Control Laboratory (now the Environmental Monitoring and Support Laboratory) was established in Cincinnati in 1969 to develp the guidelines and techniques for assuring the quality of water and waste data used by the Federal Water Pollution Control Administration. The role of the Laborator), \ + a s to develop and select the analytical methods needed to monitor the variety of pollutants found in municipal and industrial wastewater and to provide terns for the production of laborator),
results sufficiently accurate and precise for decision-making in regulation of effluent and stream standards. For the past IO years, the Cincinnati laboratory has attempted to keep pace with the increasing complexity and critical demand for reliable measurement systems and high quality laboratory results. Measurement systems The measurement method is the most critical part of chemical analysis. Measurement of the traditional pollutants described earlier could be accomplished by relatively simple instruments and equipment. In the 1 9 4 0 ‘ the ~ most sophisticated instrument in the average water laboratory was an ultraviolet-visible spectrophotometer. Today, gas chromatographs are standard and the gas chromatograph-mass spectrometer ( G C / MS) is common place.
“Adrertising claims to the contrarj, there is no list o f approied instruments for water and wastewater monitoring. ” EPA‘s Ballinger
These changing requirements for analytical methods reflect a change from the measurenient of properties to the determination of extremely small concentrations of a specific chemical structure or element. The transition from milligrams to picograms, from pH to pesticides, has been a challenge for the analyst, particularly since the constituent to be measured exists in minute amounts in a substrate containing large concentrations of a variety of interfering substances. I n order to assure that laboratory methods are adequate in water and wastewater monitoring, the EPA has insisted on standardization of analytical methods. In most environmental situations, there are niultiple sources of information. For example, in assessing the water quality of a stream reach. state agencies monitor the ambient uater to determine compliance with stream standards. An). municipal or industrial wastewater is monitored by the discharger in compliance nith permit conditions under the hational Pollutant Discharge Elimination System (KPDES). The state or EPA saniples and analy7es the bastes to verify the reported data and to prepare an enforcement action. if necessary. Combining all this information into a comprehensive re-
port is extremely difficult if a variety of analytical methods have been used by the various contributors. Conversely, uniformity of methodology eliminates a significant variable. Analytical chemistry, particularly in the environmental field, is very dynamic. New methods are continually being developed and adopted which improve the specificity, precision and accuracy, and limit of detection. Such rapid changes in methodology would appear to be hampered by standardization. In fact, quite the opposite is true if the standardization process includes provision for regular modification of the approved procedures. ImproFed techniques The early adoption of improved methods through standardization avoids the continued use of a less efficient technique. Unfortunately, there is a tendency in many laboratories to use a traditional test method because the acquisition of new instrumentation and learning new techniques may adversely affect the cost of analysis and the laboratory work load. Specification of the latest and best available technology, after careful evaluation, may avoid obsolescence. As suggested, lack of uniform laboratory methods in litigation increases the difficulty of judgment. When differing test procedures are used by the litigants, it is necessary to introduce testimony from expert witnesses to verify the methods used. Invariably the testimony from both sides conflicts, requiring an assessment of which expert is the most reliable. Traditionally the courts have been reluctant to make such judgment since the case then rests upon the qualifications of the witness rather than the reliability of the data introduced. The use of the same or equivalent laboratory methods permits attention to the significance of the data rather than how it was derived. Section 304(h) of PL 92-500 directs the administrator of the EPA to specify the test procedures to be used by N P D E S permit holders in reporting wastewater discharge data. The most recent listing of these methods appeared in the Federal Register at 40 C F R , Part 136, 52780 (December 1 , 1976). The list includes measurement methods for 1 1 5 pollutants. An amendment updating the procedures and adding new test methods for toxic pollutants will be published in late 1979. Standardization of test procedures is a requirement of the Clean Water Act Amendments and is included in implementing regulations of the Safe Drinking Water Act.
Performance audits. Adapting instrumenfati;on for on-site audits
Section 1401 of the Safe Drinking Water Act includes the promulgation of testing requirements for each contaminant in the National Interim Primary Drinking Water Regulations ( N I P D W R ) . The test procedures for water supplies were first published in December 1975 and proposed changes were published in the Federal Register a t 40 C F R , Part 14 I , 42246 (July 19, 1979). Responsibility for the selection of test procedures and recommendations to EPA program offices is the responsibility of the Environmental Monitoring and Support Laboratory in Cincinnati (EMSL-Cincinnati). The criteria used in selecting methods for promulgation are: The method should measure the required property or constituent with precision, accuracy, and specificity sufficient to meet the data needs of EPA, in the presence of the interfering materials usually encountered in water and wastewater samples. In consideration of economic requirements, the procedure should utilize the equipment and skills normally available in modern environmental laboratories, or the use of specialized instrumentation must be justified by the analytical needs. The selected method should be established by common use in many laboratories or sufficiently tested to establish its validity. The method should be rapid enough to permit routine use for the examination of a large number of samples. Often the staff of the EMSL-Cincinnati must strike a balance between the need for highly accurate procedures with good precision and the economic burden placed upon the re-
porting laboratory. Such economic considerations may preclude the use of some instrumental approaches. The requirement for unambiguous determination of specific chemical structures at very low concentrations, however, justifies the use of instruments such as the G C / M S . Available methods Methods used by the €PA for measuring water pollutants are published in manuals prepared by the EMSL-Cincinnati. Inorganic test procedures are described in EPA 60014-79-020, Methods for Chemical Analysis f o r Water and Wastes. Procedures for groups of organic contaminants such as chlorinated hydrocarbons, polynuclear aromatics, nitrosamines, trihalomethanes, and organochlorine pesticides are given in special publications. The Cincinnati laboratory conducts an active in-house and extramural research program to develop and validate new analytical methods and to improve traditional methods as necessary. To assure that the test procedure will meet the criteria for an approved method, the candidate procedure is subjected to rigorous examination of interferences and subsequently applied to actual water and wastewater samples by the research investigator. After the method is selected as the best approach, it is further evaluated through formal method validation studies, involving interlaboratory comparisons to establish the precision and accuracy in typical environmental labs. These studies are conducted by the Quality Assurance Branch, EMSL-Cincinnati, using major research institutions as prime contractors. Volume 13, Number 11, November 1979
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To avoid restricting approved methods only to those developed by EPA and to utilize the contributions of other agencies and standardization groups, the test procedures proposed for promulgation are selected from a number of references. For example, the wastewater discharger may select test procedures from the EPA manuals, Standard Methods f o r the E x amination of Water and Wastewater, A S T M Annual Book of Standards, U S . Geological Survey Methods f o r Collection and Analysis of Water Samples f o r Dissolved Minerals and Gases, or other literature. To ensure uniformity, specific methods are cited in each publication. To further avoid unnecessary restrictions on test methods, regulations provide for the use o f approved alternative test procedures. The process for obtaining approval is described in the Federal Register. Briefly, the applicant directs his request to the state or EPA regional administrator having jurisdiction over the monitoring program, describing in detail the proposed alternate procedure he wants to use. T h e request is forwarded to EMSL-Cincinnati and the Eqnivalency Staff of the Laboratory reviews the application, requests data showing statistical comparability to the approved procedure, and makes a recommendation to the appropriate EPA official. Application for an alternate test procedure may be for use on a single waste discharge or water supply, for a group of such samples, or for nationwide use. Comparability data must be sufficient to support the intended scope o f use in each case. Approximately IO0 applications for alternative procedures a r e processed annually by the Laboratory staff. Approved alternate test procedures for nationwide use a r e published in the Federal Register. The EMSL-Cincinnati is often approached for approval of specific instruments, test kits, or other laboratory and field devices. I n its water monitoring program, EPA approves only test procedures or acceptable alternatives as described above, but not specific or field instruments. Advertising claims to the contrary, there is no list of approved instruments for water and wastewater monitoring. Internal laboratory quality control While the test procedure is the keystone for good laboratory resu!ts, its use alone will not guarantee satisfactory data. A system of laboratory quality control, properly documented and rigidly enforced, is necessary. Quality control in this context includes 1364
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...
measurement of the variability produced by each step in the analysis and the specification of control measures to reduce this variability to acceptable levels. Customarily, quality control protocols include the use of carefully prepared reagents, use of high quality glassware and equipment, calibration of instruments with reference standards, and the careful computation and recording of results. Most method descriptions prepared by EMSL-Cincinnati include these steps as a part of the test method. In the case of complex measurements by gas chromatography or G C / M S , separate quality control protocols are added to ensure confidence in the reported value.
bbSpecialattention is given in EPA laboratories to the use o f control charts. The familiar Shewhart charts are used to measure and control recobery o f spiked samples while the newer CuSum chart3 establish the reproducibility o f analysis. ” EPA‘s Ball inger
To provide guidance in the development and use of laboratory quality control, EPA has published and distributed EPA 60014-79-019, Handbook for Analytical Quality Control in Water and Wastewater Laboratories. This handbook, available from
EMSL-Cincinnati, describes the factors to be considered in establishing and maintaining a good internal quality control system. I n addition to attention to chemical analysis, the handbook covers water and wastewater sampling, microbiology, aquatic biology, and laboratory safety. The manual, originally published in 1972, was revised and distributed in March 1979. Since an important factor in laboratory analysis is the performance of the analyst, special attention is given in EPA laboratories to the use of control charts. The familiar Shewhart charts are used to measure and control recovery of spiked samples while the newer CuSum charts establish the reproducibility of analysis. Preparing and maintaining control charts for each analyst and each determination requires an initial effort which is more than justified by the ability to verify that the analysis is under control or that corrective measures are necessary. The use of standard samples and reference materials from a source outside the laboratory is beneficial.
The Standard Reference Materials provided by the National Bureau of Standards have traditionally met this need. To provide reference materials more directly related to water and waste measurements, the Quality Assurance Branch of EMSL-Cincinnati has developed a series of quality control (QC) samples for use as internal controls. The samples are prepared in high purity water and are used to provide known reference values for the analyst. By spiking distilled water with the Q C sample, a known concentration of constituents is obtained, free from matrix interferences. Satisfactory performance on this sample demonstrates that the analyst is properly applying the test method. Adding the Q C sample to an actual sample of water or wastewater permits verification of the accuracy of the analysis in real-world use. The EPA quality assurance program, described by Dr. Hauser in the accompanying article, requires a QA plan for all environmental monitoring programs supported by EPA. The handbook is widely used in developing these plans and the Q C samples are available from EMSL-Cincinnati, without charge, to facilitate a satisfactory internal quality control program. The use of these samples and the performance evaluation samples described later are mandatory for EPA laboratories and for EPA monitoring contracts involving water and wastewater analysis. The samples are requested through the Regional Quality Assurance Coordinators listed or from the EPA project officer. The major effort in quality control in water and wastewater monitoring has been directed at the laboratory, on the assumption that, without a valid analytical result, all other aspects of monitoring are of little importance. There is a recognition, however, that quality control of sampling and sample handling is also necessary. To a large extent, standardization of sampling of water supplies, ambient waters, and wastewater discharges is difficult because of the variety of situations encountered. Sampling devices and procedures must be selected on the basis of the type of stream, the kind of sample, and the configuration of the source. Within these limitations, EPA prepares guidelines for obtaining representative samples, evaluates commerciallyavailable automatic samplers, and makes recommendations in its publications on sample containers, preservation, and holding times. A more intensive R & D program in sampling and
sample handling will be carried out by EMSL-Cincinnati in the coming fiscal year.
External quality assurance The discussion thus far has emphasized the application of quality assurance in the laboratory and the various ways the EMSL-Cincinnati provides guidance and assistance in achieving good laboratory practice. The EPA quality assurance program, however, also involves the verification of the quality of data by external testing. To provide a mechanism for the independent evaluation of laboratory performance, EMSL-Cincinnati has developed a series of performance evaluation samples to be submitted to participating laboratories as unknowns. These samples are designed to incorporate the elements, compounds, or characteristics of an actual sample of drinking water, ambient water, or industrial wastewater.
“Zn contrast to the Safe Drinking Water Act, approval o f certification of laboratories is not required by the Clean Water A et. ” EPA‘s Ballinger
The receiving laboratory adds the sample concentrate to distilled water, performs the analyses according to approved methodology, records the results on forms provided, and submits the results through the regional quality assurance coordinator or EPA project officer to EMSL-Cincinnati. Based on acceptance criteria developed from previous interlaboratory studies, the results are judged to be acceptable, marginally acceptable, or unacceptable, as compared to the true value. A confidential report is issued to the laboratory and corrective measures are recommended as necessary. It is readily apparent that the success of the performance evaluation rests on the validit) of the true values for the samples. T o ensure the accuracy, the samples are prepared either by the staff of the Quality Assurance Branch or by a selected contractor and the concentration of constituents verified by at least two independent analysts. Since performance evaluations are conducted as studies involving a large number of laboratories, combined statistics verify the true values in each study. Since acceptance limits are derived from actual performance by participating laboratories rather than Volume 13, Number 11, November 1979
1365
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Environmental Science & Technology
by theoretical calculation, the analyst is judged against the performance of his peers. In addition to evaluating the performance of the laboratory, these studies provide additional information on the precision of the test procedure in the hands of a typical analyst. The information is an additional check on the validity of the methods selected by EPA. Laboratory certification T h e Safe Drinking Water Act describes monitoring and analytical requirements for public water supplies and stipulates that "samples may be considered only if they have been analyzed by a laboratory approved by the For those states Lvhich have not accepted primary enforcement responsibility for the Act, the EPA regional administrator must approve the laboratory. To implement this requirement EPA has established a program for the certification of laboratories analyzing public water supplies. An EPA work group, with assistance from state authorities, developed criteria for use in interim certification. The criteria include required facilities and equipment, use of approved procedures, quality control requirements, proper data handling and reporting, and necessary staffing. Certification requires an on-site visit by a qualified inspection team and satisfactory performance annually on a set of evaluation samples. The requirements are described in the Manual for the Interim Certification of Laboratories Inrolced in Anal).zing Public Drinking Water Supplies (EPA 600/8-78-008), available from the Office of Monitoring and Technical Support, EPA, Washington, D.C. 20460. EMSL-Cincinnati assisted in the preparation of the criteria by providing expert staff and has a major leadership role in implementation of the certification program. The staff of the Laboratory provides training for regional and state inspection teams and the director certifies or recommends certification of the teams. The senior staff of the Laboratory conducts on-site visits to EPA regional laboratories and certifies them for public water supply analysis. T h e Quality Assurance Branch conducts bi-annual performance studies of all labs seeking certification and recommends approval or disapproval based upon results submitted on drinking water performance samples. T h e original National Interim Primary Drinking Water Regulations "
published in December 1975 are being amended and expanded. Additional contaminants, particularly organics, may be added to the required monitoring. In anticipation of these changes. EMSL-Cincinnati has developed additional criteria and performance samples for these new analyses. I n contrast to the Safe Drinking Water Act, approval of laboratory certification is not required by the Clean Water Act. While the quality of data submitted in the self-monitoring program is of concern to EPA. there is no formal program to certify laboratories at this time. A pilot study, jointlq conducted by EMSL-Cincinnati and the Office of Enforcement, evaluated a limited number of discharger laboratories in 1979. A large scale study, involving a number of major dischargers, may be conducted in the future. Performance on unknown samples from EMSLCincinnati will be a key factor in these evaluations. Even though no formal approval program is required, EPA regional laboratories are evaluated for their capabilities to perform analyses for the N P D E S through on-site visits by EMSL-Cincinnati personnel, and all EPA laboratories and many state and industrial labs participate in performance evaluation studies for water pollution measurements.
Dwight G . Ballinger has been incolred with M'ater polliition control since I940 arid is present1.r the director oj' the Enrironriieritul Monitoring and Support Laborator!' at Cincinnati. H e rrceiwd a B.Ph. in cheriii.strj.f r o m the L'nicersitj, of Cincinnati and is the author of more than 60 publications in the analj~ticalcheniistrj. of \z'ater and wastes and enrironniental nionitoring. Mr. Ballinger is a World Health Organization consultant in laboratorj. managenient, a member of the Anierican ChrJtwicalSociety, Water Pollirtiori Control Federation, Anierican Water Works Association. C'ommitteee D- I9,for Water o f the American Societj, f o r Testing and ililaterials, and seteral joint coriiniittees for the Preparation of Strrridard Methods for the Esauiinatioti of Water and Wasterr-ater. H e received E P A 's Silcer Meda1,for the derelopr?ient of the Agency's analj,tical qiralirj' control program in M'ater monitoring.
