AND RISK COMMUNICATION One grain of rye in 100 tons of

wheat. A needle in five tele­phone poles. Contaminants can

be detected in samples at parts-per-billion and parts-per-trillion concen­trations, and techniques for measur­ing chemicals with greater accuracy and sensitivity are constantly being developed. Many of these techniques can be used to study components of water, soil, and air that may pose en­vironmental threats.

Multispectral analysis recently evolved from GC/MS, which was first used in the late 1960s and early 1970s to identify more than 100 or­ganic compounds in water, including 2,3,7,8-tetrachlorodibenzo-£-dioxin. During the next 10 years, the proce­dure became the accepted method for the identification of target analytes in aqueous samples. EPA protocols, such as Methods 624 and 625 for 114 specific organic "priority pollutants," were developed for lab-to-lab stand­ardization.

In 1971 an automated program for the spectral identification of approxi­mately 9000 compounds was devel­oped through the collaboration of re­

sea rchers a t Bat te l le Nor thwes t Laboratories and John McGuire at the Environmental Research Labora­tory, EPA, Athens, GA (1, 2) to help experienced analysts identify ana­lytes in water samples. Based on an algorithm developed by Harry Hertz, Ronald Hites, and Klaus Biemann at the Massachusetts Institute of Tech­nology (3), the program led to the es­tablishment of a reference library of mass spectra of identified compounds

and made it possible to identify a tar­get compound by matching its spec­t rum to those in the reference li­brary. This procedure is still used to identify compounds in water, soil, and air. The reference library at the National Institute of Standards and Technology currently contains about 50,000 spectra (4).

Although this identification pro­cess is reliable in theory, it has prac­tical l imitat ions. Often, too little time is spent comparing a spectrum

with those in the reference library. Lab managers report that an iden­tification requiring the comparison of an unknown chromatogram to refer­ence spectra usually is done in less than 30 s, often by technicians who are not expert at interpreting mass spectra (5). Unfortunately, inaccu­rate identifications occur when inad­equately trained personnel either fail to distinguish overlapping peaks or do not recognize the significance of the presence or absence of certain peaks.

The use of GC/MS has other limi­tations. Compounds not extracted from the sample never reach the de­tector; polar compounds of low molec­ular weight, or compounds of high molecular weight, such as lignins, are not detected; and compounds whose mass spectra are not in the reference libraries are not identified.

A multispectral analysis approach for the identification of these nonref-erenced compounds was recently de­scribed by McGuire (5). Used in con­junction with conventional GC/MS and GC/IR, the multispectral method incorporates high-accuracy mass de-

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MULTISPECTRAL METHODS OF ANALYSIS

FOCUS

FOCUS termination for identification of the elemental composition of ions, FT-IR spectroscopy for recognition of sub-molecular s t ructure, and chemical ionization MS for determination of molecular weight. These techniques are applied when attempts to match a GC/MS spectrum with the refer­ence spectra fail to produce a reliable identification of an analyte. The re­sults are melded together to give a total picture of the structure of the molecule.

When identifications made by IR and MS agree, a structure can be postulated with a reasonable amount of confidence. McGuire comments, "Surprisingly, spectral matching has been successful more often than not, in spite of the fact that a reference li­brary of even 100,000 spectra is but a small fraction of the 10,000,000 com­pounds that have been reported." He describes the multispectral analysis approach for determination of the s t ructure of an unknown as "just good analytical chemistry."

The multispectral approach was used to elucidate the structure of an unidentified unsa tura ted aldehyde for which neither MS nor IR library spectra existed. Spectra from GC/MS, IR, chemical ionizat ion MS, and high-accuracy MS analyses led to the determination of the location of the olefinic bond and a positive identifi­cation of trans- 2 -octenal. In another sample, GC/FT-IR established the presence of a - O H group in a com­pound previously identified by GCV MS alone as methylbenzofuran, lead­ing to the correct identification of indenol. In another application, alkyl and chloroalkyl phosphates were pre -cisely identified in the effluent of a manufacturing plant (6).

The usefulness of this technique is also demonstrated in the reanalysis of a sample described in a contract laboratory report (7). The report cor­rectly identified three target com­pounds, and it tentatively identified three other compounds. However, it failed to identify 16 other compounds that represented some of the largest peaks in the GC/MS chromatogram. Fur ther analysis of the sample by high-accuracy MS, chemical ioniza­tion MS, and GC/FT-IR led to the conclusion that only one of the tenta­tive identifications was correct and that the other two assignments actu­ally corresponded to compounds that had never been reported and there­fore did not have spectra in the refer­ence library. The three peaks were ident i f ied as s u b s t i t u t e d d iben-zofurans. Now identified, their spec­tra can be added to the reference li­

brary, and their identification in the future will be easier.

Unfortunately, the multispectral approach is time consuming and re­quires expensive ins t rumenta t ion. McGuire estimates that 200 h was spent in the reanalysis, confirmation, and identification of the six sub­stances reported in the contract labo­ratory sample. Together, a high-accuracy mass spectrometer and a GC/IR instrument cost approximate­ly $500,000-$750,000. A laboratory would need a strong incentive to pur­chase such costly equipment, and at this time there are only ~ 100 labs in the United States, including three EPA labs, so equipped. However, the expertise needed to meld the infor­mation together is not always found in the same laboratory, and, when it is, "turf" conflicts between mass spectrometrists and molecular spec-troscopists may prevent its use.

Fortunately, a sample determina­tion can be a collaborative effort with more than one laboratory involved in a single analysis. McGuire emphasiz­es, however, tha t the multispectral approach is necessary only when components cannot be identified. Currently, nonidentified components are ignored, even though they may represent highly toxic or carcinogenic compounds. Because the multispec­tral approach can help to identify such components, it has great poten­tial in the field of environmental an­alytical chemistry.

Identification of previously unre­ported compounds in environmental samples raises additional concerns. What happens when they are mixed with other chemicals? What happens while they spend years in a dump-site? What happens to animals and humans exposed to them? Frequent­ly these quest ions cannot be an­swered, and, thus, the risks associat­ed with human exposure cannot be assessed. But if human exposure is possible, or has already occurred, these concerns become very real.

These are issues with which per­sons involved with risk assessment and communication struggle. Risk assessment involves evaluation of the safety hazard posed by the use of, or exposure to, a chemical, and is usually extrapolated from available laboratory and/or epidemiological data. Risk communication is the pre­sentation of this information to the concerned community.

According to Vincent Covello, di­rector of Columbia University's Cen­ter for Risk Communication, the pub­lic's perception of the heal th risk posed by chemicals has changed in

the past 10 years (8). His research shows that 10 years ago most people in the United States believed that 10% of all cancers were caused by lifestyle factors such as smoking, diet, and lack of exercise; that anoth­er 10% were caused by exposure to chemicals in the environment; and that the remaining 80% were attrib­utable to fate or natural causes. To­day, however, most people still be­lieve tha t 10% of all cancers are caused by lifestyle factors, but they attribute 5% to fate and the remain­ing 85% to chemical exposure. An even more alarming finding is that most science teachers believe that 80% of all cancer cases result from chemical exposure.

Covello explains that the general public has many negative impres­sions about chemicals. For example, people perceive that most chemicals in the home are found under the kitchen sink or in the bathroom med­icine cabinet and are a source of dan­ger. He says that most people fail to realize that chemistry is involved in all facets of daily living—from tooth­paste to living room carpet to com­puter chips to bedroom slippers. Cov­ello a s s e r t s t h a t more effective communication is needed about our dependence on chemicals in daily life.

Covello's results also indicate that during the past 10 years industry and government have lost substan­tial credibility in the eyes of the pub­lic, in part because of the public's perception that government has not been honest, is not competent, does not care about environmental issues, and is not committed to solving envi­ronmental problems. This loss of trust and credibility makes it even more difficult for government and in­dustry to communicate effectively with the public about issues of chem­ical safety.

Covello proposes three steps for bridging this credibility gap. First, government and industry must make a concerted effort to win back the public 's t r u s t and credibi l i ty by showing that they are honest, compe­tent, caring, and committed to solv­ing environmental problems. Second, they must draw on the credibility of those whom the public still t rusts, such as medical doctors and univer­sity scientists. Third, government of­ficials need to improve their r isk communication skills. As these im­proved skills are utilized, the public's understanding of chemical safety and risk will increase.

Covello explains that effective com -munication about the important role played by chemicals in daily life is a

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requirement for discussion of chemi­cal risk. Such communication does not occur without effort; it is a skill that must be learned, developed, and practiced. The process must include scientists, media specialists, chemi­cal manufacturers, government offi­cials, and regulatory representatives, and it must be directed toward the general public. The goal must be to make the public a partner in deci­sions affecting the use of chemicals in the market, the workplace, and the environment.

An important point that Covello makes is that the public must under­stand that no chemical can be certi­fied as completely safe, but that its risks can be evaluated. An educated public should ask, "How safe is it?" rather than "Is it safe?" Information about chemicals must be presented honestly and clearly.

Covello stresses that teachers and schools must also become involved. Issues such as chemical testing, haz­ard evaluation, and risk assessment should be taught in the schools. Cur­ricula for these topics for all grade levels need to be developed.

Covello summarizes, "Given the

high degree of public concern about environmental issues and the high level of public distrust of those in in­dustry and government, people re­sponsible for assessing and manag­ing chemical risks have no choice but to improve their risk communication skills."

Evaluation of environmental risk begins in the lab. Through a battery of analytical techniques and new de­velopments, such as multispectral analysis, compounds found in the en­vironment can be detected and iden­tified. Only when compounds are identified can the i r benefits and risks can be assessed. After chemical risks are evaluated and discussed, decisions regarding use and exposure can be made. In some cases the bene­fits may outweigh the risks; in others they may not. But a decision made by an educated, informed public is the result of effective risk assessment and communication. Such decisions are possible only when scientists, manufacturers, regulatory officials, media representatives, and the gen­eral public deliberate together, using the best possible analytical informa­tion. Jane K. Baker

References (1) McGuire, J. M. Prog. Water Technol.

1975, 7, 23-31. (2) Hoyland, J. R.; Neher, M. B. Implemen­

tation of a Computer-Based Information Sys­tem for Mass Spectral Identification; U.S. Environmental Protection Agency, 1974; EPA-660/2-74-048.

(3) Hertz, H. S.; Hites, R. Α.; Biemann, K. Anal. Chem. 1971, 43, 681-91.

(4) Lias, S. G. /. Res. Nat. Inst. Stand. Te-chol. 1989, 94, 25.

(5) McGuire, J. M. Presented at the 21st International Symposium on Environ­mental Analytical Chemistry, Jekyll Is­land, GA, May 1991.

(6) Thruston, A. D., Jr.; Richardson, S. D.; Collette, T. W.; McGuire, J. M. /. Am. Soc. Mass Spectrom., in press.

(7) McGuire, J. M.; Collette, T. W.; Thrus­ton, A. D., Jr.; Richardson, S. D.; Payne, W. D. Multispectral Identification and Con­firmation of Organic Compounds in Waste­water Extracts; U.S. Environmental Pro­tection Agency, 1990; EPA/600/S4-90/ 002.

(8) Covello, V. T. Presented at the 21st In­ternational Symposium on Environmen­tal Analytical Chemistry, Jekyll Island, GA, May 1991.

Suggested reading Effective Risk Communication: The Role and

Responsibility of Government and Nongov­ernmental Organizations; Covello, V. T.; McCallum D.; Pavlova M, Eds.; Plenum Press: New York, 1989.

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