Chemical Analysis— A W e a p o n Against Water
POLLUTION A. A. Rosen Federal Water Pollution Control Administration, Cincinnati, Ohio
"IT 7"ATER POLLUTION is an environ* " mental problem; as such, it calls upon specialists in most of the physical and social sciences. That chemists, bacteriologists, and biologists play important roles in pollution control is widely recognized. But this problem field must also call upon economists, legislative specialists, and finance experts, among others. In all this array of specialties, the contribution of the analytical chemist is among the most important. He is especially challenged by organic chemical pollution—inorganic pollutants are less difficult to investigate. Both Industrial and Government Agency Chemists Fight Water Pollution
This analytical chemist may operate within an industry that is a pollution source. He has the opportunity to know his company's products and processes and what pollution risk they pose in the factory or mill waste discharges. He has access to the waste streams throughout the manufacturing plant. By analyzing these streams, he discovers any sources of excessively polluted wastes; often such wastes are due to inappropriate processes or neglectful operation (1). Thus, the chemist is able to inform management where the most urgent waste treatment needs are in the industry. When treatment facilities are then provided, anal26 A
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ysis of the treated effluent monitors the efficiency and care in operation of waste treatment processes. In these ways, the industrial chemist contributes to the reduction of water pollution. The water pollution control chemist functions, instead, within control agencies of the various levels of government, ranging from municipal to international treaty organizations. He does not know adequately the processes and products of any of the industries discharging to and polluting a body of water. This information is usually classed as trade secrets. In most cases he is not privileged to sample within the plants suspected of polluting. In any case, industries are frequently crowded into intricate area complexes that make detailed internal studies beyond the resources of control agencies. A regional promotion map shows 31 industrial facilities, most of them large chemical manufacturers, along less than 50 miles of the Kanawha River (see Figure 1). Investigation of a water pollution incident requires techniques analogous to those of forensic science. The pollution chemist is usually called in after the damage has been done and the chemical culprit has vanished downstream. Moreover, the point where damage is noted and a complaint made is often well downstream from the responsible waste outfall. In 1958,
REPORT FOR ANALYTICAL CHEMISTS
we identified an unusual and toxic organic chemical pollutant, o-nitrochlorobenzene, in the Mississippi River at New Orleans (£?) [see Figure 2 ] . This was finally traced to an industrial waste discharge at St. Louis, about 900 miles upstream. Sometimes the pollution cause-andeffect relationship requires other specific circumstances. A petrochemical waste discharged into a Canadian river traveled across the provincial boundary and caused an extremely disagreeable taste and odor in the drinking water of a city more t h a n 500 miles downstream {8). This problem occurred only in winter when the river was frozen and became virtually a pipeline of ice. Even time can be a misleading factor in pollution studies. Examples are commonplace of offensive wastes t h a t settle undetected as sludges, to cause trouble months later when a sharp rise in the river transports these deposits to a downstream water plant intake.
IPhoto courtesy of U. S. Department Washington, D. C J
of the. Interior,
Federal
Water Pollution
Control
Administration,
Figure 1. A petrochemical plant, one of the 31 industrial facilities along the Kanawha River in West Virginia. Some of the many waste outfalls are shown. They can only be identified with specific manufacturing operations by use of information voluntarily supplied by the industry
S a m p l i n g Problems in W a t e r Pollution Control
The similarity to a forensic investigation becomes vivid when the chemist starts to collect samples. H e must start in public areas and is often limited to these. His samples are taken from publicly available streams or lakes. Examination of these samples suggests, in the light of prior experience, what classes of organic wastes may be responsible. I n this examination, conventional analyses are supplemented by taste or odor tests and by bioassays for agents toxic to aquatic life. W h a t ever his inferences, the water pollution chemist, like the forensic chemist, does not expect t h a t the p a r t y committing the offense will come to him with the samples he needs or will willingly give access to them. The required samples are gathered wherever they can be taken, by boat or from bridges. Usually these places are the affected stream, above and below the suspected discharge points, and especially, the suspected waste outfalls. These must be sampled in public
6 7 8 9 10 11 12 WAVELENGTH IN MICRONS Infrared spectra of pure ONCB and extracts from water
Figure 2. Infrared spectra traced a specific chemical pollutant 900 miles along the Mississippi River VOL 39, NO. 12, OCTOBER 1967
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areas—at the river's edge, usually reached by boat. Even at outfalls, sampling is difficult. The chemist will find a confusing a r r a y of pipes, discharging streams of many volumes and temperatures. Owners of the outfalls are seldom indicated. Some outfalls are concealed in weeds or are inaccessible, high up on a cliff-like shore. Others are submerged and unmarked. Still other discharges are intermittent and variable; they do not resemble at the time of sampling the previous flow and composition t h a t caused a pollution incident. When the required samples are collected, they are presei'ved in ice and returned to the laboratory for analysis. The weight of samples, ice, and ice chests rapidly taxes the capacity of the sampling boat and constitutes a logistic limitation on the number of samples. A very few pollution investigators have introduced the use of floating laborator-
[Pfioto courtesy of Hudson-Champlain Project, Federal Water Pollution Control Administration, .Metuclien, New Jersey]
Figure 3. Shipboard laboratories, such as this one in service on the Hudson River and Lake Champlain, add to the power of chemical analysis in combating pollution. The investigation is not retarded by transportation of samples to a central laboratory. The investigation can change emphasis promptly as suggested by unexpected analytical data 28 A
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ies which allow much greater flexibility in number and spacing of samples. This floating laboratory approach, resembling practices common in oceanography, will become much more common (see Figure 3 ) . C o m p l e x i t y of Organic C h e m i c a l Pollution
Seldom can chemical proof of water pollution rest on simple analysis. Most presumably unpolluted surface waters contain important concentrations of natural organic substances derived from decaying vegetation or photosynthetic activity of aquatic organisms. These humic substances are especially conspicuous in southern waters (4) • Other natural organics are microbial metabolites, some of which are notorious offenders in odor problems (5). The concentration of natural organics in surface waters usually far outweighs t h a t of even the severe industrial pollutants. For example, analyses of total organic carbon in the K a n a w h a River above and below the industrial complex mentioned previously showed only a 5 to 10 percent increase due to industrial wastes, over the 10 ppm characteristic of the river. Pollution introduces countless organic compounds. Some are biological products in sewage and wastes from food and fermentation industries. These compounds are not usually determined individually, but the numerous components of synthetic organic wastes have distinct pollutional characteristics and may require specific analyses. As an example of how many compounds can be involved in a single area, the catalog of just one of the companies in the K a n a w h a River industrial complex referred to shows 717 products, some being produced in other locations, of course. T h e variety of waste components discharged contains not only the marketed products, but also the raw materials, intermediates, and by-products used in or created by the manufacturing processes. And this admixture is always changing. The 1960 and 1965 catalogs of the same company
Figure 4. A truck-mounted centrifugal liquid-liquid extraction system for sampling organic chemical pollutants can respond rapidly to critical spills or fish kills. A convenient water sample of 1000 gallons can be extracted in a few hours with a choice of lighter- or heavier-than-water solvent. The sampling system includes a second truck, carrying a generator to power the centrifuge and the necessary supply of extraction solvents
were compared. Ninety of the 1960 products were dropped, to be replaced in 1965 by 152 new products. Analysis of Specific Organic Pollutants
The objectives of pollution analysis are to determine the nature and severity of damage to water use, establish responsibility at the point of discharge, determine the effect of natural forces {e.g., climate, tide, streamflow) in transporting and modifying pollutants, and to measure the success of efforts to reduce pollution and to comply with abatement requirements. Some compounds cause serious pollution at concentrations as low as 1 ppb or less. Sometimes thousands of gallons of water sample are required to obtain enough of such contaminants for complete analytical procedures. To meet this need, sampling methods have been de-
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vised that separate the organic con taminants from the necessarily large volume of water. These methods are based on adsorption by active carbon (6) or liquid-liquid extraction (7) [See Figure 4]. In the carbon adsorption methods, or ganic pollutants are recovered by exhaustive extraction of the carbon with an organic solvent, usually chloroform. These methods not only recover the required amounts of organic contaminants, but also produce the water-free extracts that are necessary for the common meth ods of organic analysis. Further more, these extracted samples may be stored for analysis years later. Indeed, many have been stored and analyzed by methods developed long after the samples were col lected. These extracts may contain many hundreds of components which must be separated for anal ysis. Conventional methods of or ganic analysis such as distillation, selective solubility in acidic and basic solutions, and crystallization are used. For such complex mixtures, however, newer separa tion tools are also required. Com plex formation—urea complexes of straight chain aliphatics and chloroplatinic acid complexes of bases—has been applied successful ly. Chromatography in all its vari ations—column, paper, and thinlayer—is even more useful. It has been used to identify petroleum refining wastes (8) and to separate chlorinated insecticides concentrat ed in tissues of fish taken from pol luted streams (9). Gas chromatog raphy is the most powerful separa tion technique available to the water pollution chemist. After the water-free extracts have been sep arated as far as practical by con ventional methods, the fractions are further separated by semi-prepara tive scale gas chromatography, using 1 / 4 -inch or 3 / g -inch col umns. Only this procedure is like ly to yield useful quantities of indi vidual organic pollutants in pure enough form for identification. The separation procedures de scribed lead part way to identifica tion. The classical methods of or
ganic analysis have been employed ; however, even the best separation methods often yield fractions still too impure for melting-point deter mination or derivative formation. The most widely used identifica tion technique is infrared spectrom etry (IR). The original identifi cations of detergents as the cause of foam on rivers (10) and of chlori nated insecticides as water pollu tants (11) were made by IR. The pure contaminants isolated by gas chromatography are especially suited for IR identification when incorporated into micro-KBr discs. Proof of identity of pollutants that is acceptable to non-scientists is a must in pollution control en forcement. In this respect, the widely used comparison of infrared to fingerprints is very effective. There are varying degrees of positiveness of pollutant identification: • Characteristic peaks present in gas chromatograms of mixed fractions on two or more col umns, (least positive) • Characteristic peak on gas chromatographic column is trapped and gives appropriate peak on at least one other col umn, (intermediate) • Characteristic peak on gas chromatographic column is trapped and gives the proper infrared spectrum, (most posi tive) Besides infrared, the development of specific detector systems such as electron capture, microcoulometry, and thermionic emission adds to the identification capabilities of gas chromatography. Once qualitative analysis of water pollutants has been made, quantitative analysis is less diffi cult. The hydrogen flame ioniza tion detector is so sensitive that a polluted water sample of one gallon or less contains enough contami nants for gas chromatographic anal ysis—when there is no question of identity of peaks. After identifying the contami nants and measuring their concen tration, it is necessary to prove that these substances are responsible for
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observed water quality deteriora tion. This proof uses specialized analytical methods. If the pollu tion effect is a fish kill, fish bioassay proves that the concentrations of toxic agents found in the water are enough to kill fish. Most often, offensive odor in drinking water drawn from the polluted stream is the major effect. Threshold odor tests of the recovered pollutants will establish them as the cause {12).
Proof of the origin of pollution is the capstone in assembling an abatement case, after the evidence described above has been gathered. Ideally, each outfall is sampled and analyzed and the responsible plant identified. Sometimes, it is pos sible to establish responsibility only by sampling the river above and below the source. Grab samples are usually adequate for this pur pose. By continuing this type of analysis at intervals downstream, the pollution is traced to the point where its harmful effect has been observed. The same sampling pro tocol is used to show whether any other sources contribute to the ef fect, how far it persists down stream, and how effective subse quent abatement measures are in overcoming the observed pollution. In establishing the relative con tribution of the organic chemical industry to pollution, radiocarbon dating has been used as a tool to measure the proportions of indus trial and municipal wastes in sur face waters (IS). Finally, the chemist must as semble his evidence in a manner convincing to the officials having pollution abatement authority. One effective method is the "wit ness kit." Packaged in this kit is a series of vials containing visible quantities of the major responsible compounds isolated from polluted water at the site of impaired water use (see Figure 5). The kit also contains a parallel series of vials of the same compounds, isolated in the same way from the responsible waste outfall. Laymen do not fail to understand the correlation.
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gineering Center, Cincinnati, Ohio, June 15, 1954. (4) R. F. Christman and M. Ghassemi, / . Am. Water Works Assoc, 58, 723 (1966). (5) J. K. G. Silvey and A. W. Roach, Public Works, 87, 103 (1956). (6) H. Braus, F. M. Middleton, and G. Walton,
ANAL.
CHEM.,
23,
1160
(1951). (7) R. L. Bunch and M . B. Ettinger, Proc. 20th Purdue Industrial Waste Conf. Engineering Ext. Series No. 118, p. 93 (1966). (8) A. A. Rosen and F . M . Middleton, Figure 5. The "witness k i t " provides convincing proof of the cause and effect relationship in chemical pollu tion of streams. It contains a series of samples of the principal chemicals isolated from polluted water at the point where use is impaired. A par allel series of samples is shown as isolated from the responsible waste outfall
Summary
Chemical analysis is used b y b o t h industrial and control agency chemists to combat water pollution. T h e control agency chemist has the more difficult analytical problem because he knows relatively little a b o u t t h e industrial processes in volved and must operate in public areas. An enforcement case r e quires t h a t t h e responsible com pounds a t the site of water use im p a i r m e n t be identified. Quantita tive analyses along the polluted body of water establish responsibil ity and assess the degree of damage. M o s t of t h e resources of chemical analysis are d r a w n on to assemble the d a t a needed to accomplish pol lution abatement. Even more so phisticated methods will be called upon as the problems of the envi ronment inevitably receive more a t tention. Literature Cited (1) L. G. Cochran and F . D . Bess, / . Water Pollution Control Federation, 38, 2002 (1966). (2) F . M. Middleton, "Report on the Recovery of Orthonitrochloroben.zene from the Mississippi River," Robt. A. Taft Sanitary Engineering Center, Cincinnati, Ohio, June 22, 1959. (3) F . M . Middleton, "A Report on the Study of Water and Wastes from the Edmonton, Alberta, and Prince Albert, Saskatchewan, Canada Areas," Robt. A. Taft Sanitary E n
ANAL. CHEM., 27, 790 (1955).
(9) H. W. Boyle, R. H. Burttschell, and A. A. Rosen, "Organic Pesticides in the Environment," Advances in Chemistry Series, No. 60, p. 207, Am. Chem. Soc, Washington, D. C , 1966. (10) A. A. Rosen, F . M. Middleton, and N. W. Taylor, J. Am. Water Works Assoc, 48, 1321 (1956). (11) A. A. Rosen and F . M . Middleton, ANAL. CHEM., 31, 1729 (1959).
(12) A. A. Rosen, R. T. Skeel, and M. B. Ettinger, / . Water Pollution Con trol Federation, 35, 777 (1963). (13) A A. Rosen and M. Rubin, / . Water Pollution Control Federation, 37, 1302 (1965).
(Patent Pending )
FOR
REPEAT ANALYSES
A. A. Rosen is acting chief of the Waste Identification and Analysis Ac tivities of the Cincinnati Water Re search Laboratory of the Federal Water Pollution Control Administra tion. He received the Ph.D. degree in organic chemistry in 1938 from the University of Cincinnati. He has been engaged with water pollution re search since 1952. His former associations were with the U. S. Patent Office, Devoe and Raynolds, and Jos. E. Seagram and Sons, plus 5 years of wartime service with the Chemical Warfare Service. His in terests in safeguarding the aquatic envronment are also personal—he is an enthusiastic sailor
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