V O L U M E 28, NO. 12, D E C E M B E R 1 9 5 6 the same conditions. The system obeys Beer’s law up to approximately 25 y of sulfur dioxide per 10 ml. Nitrogen dioxide interferes if present in concentrations above 2 p.p.m. Higher levels decrease the color intensity and nitrogen dioxide concentrations over 8 p.p.m. prevent color development completely. The only other common interference, usually associated with the reagent, is sulfide. I n the presence of the mercury-absorbing solution, this ion precipitates and may be removed by filtration or centrifugation. Sulfur trioxide, chlorine, ammonia, and halogen acids do not interfere.
1819
and analyzed a t any later time with no loss of sulfur dioxide due to either oxidation of volatilization. SUMMARY
A procedure for the fixation of sulfur dioxide is based on the formation of stable, nonvolatile disulfitomercurate(I1) ion. The determination is based on the red-violet color developed when sulfur dioxide or disulfitomercurate(II), p-rosaniline, hydrochloric acid, and formaldehyde are mixed. The method is sensitive, reproducible, and accurate.
RECOMMENDED PROCEDURE FOR DETERMINATION OF SULFUR DIOXIDE IN THE ATMOSPHERE
Collect 38.2 liters (1.35 cubic feet) of sample in 10.0 ml. of sodium tetrachloromercurate(I1) solution in a small fritted bubbler. The sampling rate may be as high as 0.2 cu. foot per minute with no loss due to decreased efficiency of absorption. To the 10.0-ml. sample add 1.0 ml. of acidic p-rosaniline solution and 1.0 ml. of formaldehyde solution. Treat a blank of 10 ml. of sodium tetrachloromercurate(I1) in the same manner. Allow to stand 20 to 30 minutes for full color development. Determine the absorbancy of the test solution compared t o the blank a t 560 mp. Read the concentration of sulfur dioxide from a standard curve prepared by using standard solutions of sodium bisulfite in sodium tetrachloromercurate(I1). If the sample size is 38.2 liters, then each microgram of sulfur dioxide represents 0.01 p,p.m. of sulfur dioxide in the air. Sitrogen dioxide is the only interference m-ith this method, and i t can be tolerated in concentrations up to 2 p.p.m, (if sulfides are present, the precipitate formed must be removed by filtration or centrifugation). Samples may be collected in the field
ACKNOWLEDGMENT
The authors wish to express their thanks to the Mine Safety Appliances Co. for financial assistance during part of this investigation. LITERATURE CITED
(1) Atkin, S., .&SAL. C H E l f . 22, 947 (1950). (2) Feigl, F., “Chemistry of Specific, Selective and Sensitive Reactions,” p. 75, Academic Press, Kew York, 1949 (3) Fieldner, A. C., Oberfell, C. G., Teague, 11.C., Lawrence, J. S . , J . Ind. Eng. Chem. 1 1 , 523 (1919). (4) Holmes, J. A, Franklin, E. C., Gould, R. b.,U. S. Bur. Mines Bull. 98 (1915). ( 5 ) Jacobs, lf. B., “Analytical Chemistry of Industrial Poisons, Hazards, and Solvents,” 2nd ed., pp. 758-9, Interscience, Kew York, 1949. ( 6 ) Steigmann, A . , J . SOC.Chem. Ind. 61, 18 (1942). (7) Thomas, 51. D., IND.ESG.CHEM., ANAL.ED.4, 253 (1932). (8) Urone, P. F., Boggs, W. E., A i i . 4 ~ .CHEM.23, 1517 (1951).
RECEIVED for review J u n e 20, 1936. Accepted October 2 ,
1956.
Ninth Annual Summer Symposium-Analysis of Industrial Wastes
Recent Trends in the Analysis of Industrial Wastes W. ALLAN MOORE and M. B. ETTINGER Robert A. Tart Sanitary Engineering Center, Cincinnati, O h i o
Surface waters are becoming progressively scarcer, and their use for disposing of liquid industrial waste should be continually re-examined. Intelligent control of waste discharge must be based on analytical methodology, which does not appear to be keeping pace with the problem that confronts it. Requirements for discharge of wastes to surface waters will become increasingly critical.
E
STIRIATES based on “population equivalents” (28) rate industrial wastes as responsible for more than twice as much stream pollution as municipal sewage discharges. It has been further estimated that betn-een 1950 and 1975 population will increase by about one third and industrial production will double. Estimates by chemical industry ( 1 7 ) of future expansion make these statements on industrial growth seem highly conservative. Production increase 6 1 1 obviously be accompanied by increasing use of water. The future growth of water use is likely t o occur in a framem-ork of shrinking availability of surface water. The existing xater shortages in the arid areas of the country are m-ell understood. Supplementary irrigation in humid areas is increasing rapidly. This consumption of vater occurs during dry summer periods, when. most streams have their lowest flow of the year, and it has been estimated (31) that it can use the entire flow of
many streams, even if only a small fraction of 1% of the land in a watershed is irrigated. Municipal use of water is increasing faster than population. Thus, the average urban dweller uses 150 gallons of water today, whereas 30 years ago he used only 20 gallons (11). Recreational use of water is harder t o assess, but both increased leisure time and increased income are causing the public to demand more water resources for recreation. Requirements for discharge of wastes t o surface waters will, of necessity, become increasingly critical. Analytical means of gaging the suitability of wastes for discharge must be developed further as implements for protecting an increasingly critical public interest in Tater quality, without unduly hampering industrial activity. IR~STRUMENTATION
The analytical work in progress does not appear to be adequate in relation to the expanded and critical rraste control problem which it must eventually meet. Perhaps the most hopeful sign is the awakening interest in instrumentation as a means of lecording waste properties or stream quality. .\long with others, the Sanitary Engineering Center (14) is moiking toward the development of a machine for continuously indicating and recording dissolved oxygen in surface water. Kieselbach ( I S ) of D u Pont has reported on an apparatus for continuous recording
1820
ANALYTICAL CHEMISTRY
of organic concentration in waste water. This instrument is expensive, but is a significant step in development. The means for recording pH, conductivity, oxidation-reduction potential, and color are available for use in controlling industrial wastes or stream quality. NEW PIRARIETERS
Kew industrial developments will cause new parameters of pollution to appear. For instance, the color and ligneous materials associated nith paper mill wastes have generally been of less concern than the organic portion of the waste, which is subject to rapid biological destruction with concurrent depletion of oxygen in receiving streams. However, lignin sulfates now find commercial use as dispersing agents, and are used to prevent coagulation of both solids and liquids (26). I t would be reasonable to assume that the same material in a surface water might interfere with its coagulation in water treatment processes. It may be readily predicted that tests for tannins and lignins ( 1 ) will find increasing use and will undergo further laboratory refinement. BIOASSAY TECHNIQUE
One important area of waste analysis cannot possibly be adequately covered by the chemist: the development of a basis for predicting the effects of a waste on the survival and growth of fishes and other aquatic life. Chemical limits on the permissible quantities of fish toxicants may be suggested, but they are not completely satisfactory. For instance, Doudoroff and Katz (6) cite one study in which, under a given set of test conditions, fishes survived 8 p.p.m. of zinc alone and 0.2 p.p.m. of copper alone but were killed by a combination of 1 p.p.m. of zinc and 0.025 p.p.m. of copper. A really sound estimate of the effect of industrial discharge on fish populations requires complicated procedures ( 4 ) . The routine bioassay (6) for evaluating the acute toxicity of industrial wastes to fishes may be expected to come into more common use. TOXICOLOGICAL EXAMINATlON OF WASTE
Responsible manufacturers do not market a product for either internal use or dermal application by man without exhaustive studies of its toxicological characteristics and continued close quality control. But surface waters a t present serving millions of people are continuously dosed with industrial wastes containing undetermined amounts of unknown chemicals of undetermined toxicity. I n the field of atomic energy there is record of sustained examination of wastes to preclude the entry of harmful amounts of toxic materials into natural water courses. Industry, in entering the radiation application field, has scrupulously followed the pattern of operation established by the Government (29) in the days of the Manhattan Project. Close and sustained observation and control of the toxic content of wastes may be expected to grow. The concern felt by a state compact group over the problem of possible toxicity associated with industrial waste pollution was expressed by Cleary (3)as follows: What toxic effects to man and animals may result from continued consumption of water contaminated with industrial wastes? Or from end products of organic decomposition? Or from treatment of certain raw water supplies by chemical means? These are questions that cannot be ignored by those concerned with water quality. These questions have special meaning to the Ohio River )‘alley Water Sanitation Commission, dealing as it must with the establishment of industrial waste control procedures. At present the authors are aware of only one case where organic chemical waste discharges are continuously examined for acute
and chronic toxicity to mammals. However, in the next 20 years, there is bound to be an increasingly close scrutiny of the toxicity to humans of industrial wastes discharged to surface waters that are subsequently used as domestic water supplies. The toxicological examination of wastes and the analytical methodology to accompany it are not well defined but may soon be a matter of major concern.
RE-EXABZINATION O F TR.4DITIONAL PROCEDURES
The analytical procedures now used to measure industrial wastes are largely nonspecific tests drawn from the traditional techniques first devised for use in sewage disposal practice, assessment of stieam pollution by sewage, and operation and control of water purification processes. Perhaps the procedures which have undergone the greatest recent re-evaluation are the biochemical oxygen demand test (most frequently 5-day B.O.D.), oxygen consumed, chemical oxygen demand, if preferred, and threshold odor. An overwhelming mass of evidence has demonstrated that the real B.O.D. of an industrial waste frequently cannot be satisfactorily measured unless an effective seed is developed (7, IO, 19, 2 7 ) . The increasing awareness of the difficulty of developing seeds has led to an increasing interest in long-term B.O.D. techniques. Examples of this trend are the “two-jug technique” (24) and the technique described by Mills and Stack (20), who recommended long-term B.O.D. studies using acclimated seeds as the preferred method for making a realistic measurement of the B.O.D. of industrial wastes. Two procedures for determining the 5-day B.O.D. (1) (with che choice of method left to the analyst) which differ in manipulative detail, do not necessarily give identical results and may lead to differing views on equitable sev-er rental charges for industrial wastes. This situation has been described in some detail (8) and is now under consideration by ASTM Committee D-19. It appears that B.O.D. may be redefined as “the amount of dissolved oxygen used both biologically and chemically under specified conditions.” Oxygen consumed (O.C.) or chemical oxygen demand (C.O.D.) has resumed its status as a measure of waste quality rather than a poor basis for estimating B.O.D. This usage of the oxygenconsumed test has been advocated periodically by the authors and their colleagues (8, 9, 21), and appears to be midely accepted by those concerned with industrial wastes. C.O.D. sometimes shows close correlation with B.O.D., and has been found in a t least one case to be a satisfactory basis for operation of a waste disposal plant (12). The expanded use of the oxygen-consumed test may be attributed to improved and extended technique ( 3 2 , 2 3 ) . Problems in the measurement of oxygen consumed in the presence of large emountsof chloride are in the joint presence of chloride and nitrogenous material are being examined in the Sanitary Engineering Center laboratories, and are also the subject of research in England, where these difficulties first had close scrutiny (SO). I n commenting on the standard procedure adaptable to industrial wastes, the present situation with regard to nitrogen determinations deserves mention. The Kjehldahl digestion should be markedly improved as the result of studies by McKenzie and Wallace (16), and the nesslerization technique ( 1 ) appears to give good results. The nitrate procedures for sewage and industrial wastes, after being standard for years, have been allotted “tentative” status ( 1 ) in recognition of the difficulty of obtaining reproducible results with the available methods. The possible eRect of industrial effluents on the taste and odor of drinking water has received increased scrutiny. Drinking water is almost invariably chlorinated (8), so that the organoleptic properties of chlorinated dilutions of waste are the properties to be measured, and the variability of the sensory percep-
V O L U M E 2 8 , NO. 1 2 , D E C E M B E R 1 9 5 6 tion of observers should also be taken into account in rating taste or odor by the threshold technique. SEARCH FOR INCREASING SPECIFICITY AND SEh-SITlVITY
There is a current trend ton-ard sharpening the specificity of the identification of waste components, where technique can be devised and the existing situation demands such revision. I n the Sanitary Engineering Center, for instance, Rosen and Burttschell have applied four different techniques-ultraviolet absorption, infrared absorption, x-ray diffraction of derivatives, and color reaction-to produce very firm evidence of ground water pollution by specific chemicals also present in an industrial lagoon. Sallee ( 2 5 ) gives evidence of this trend; a high degree of specificity for alkyl benzene sulfonates is sought and the desired sensitivity obtained by preliminary concentrat,ion through the use of carbon. For studies of the persistence of motor oil hydrocarbons, Ludzack and Whitfield ( 1 5 )devised more definitive procedures for “oil” than any previously used. The carbon absorption technique ( 2 , 18) has in some cases enormously increased both the sensitivit3- and the specificity of analysis by making it possible for the analyst to work conveniently with a 5000-gallon sample of water, or with up to a 100gallon sample of industrial Taste. This technique has been used a t the Sanitary Engineering Center by Rosen and coworkers to detect and later identify part per billion quantities of insecticides. I t is expected that both sensitive and specific general-purpose procedures for the commoner chlorinated insecticides will develop. There will be a groiving need for more specific information on the actual chemical composition of industrial wastes, and of‘ the chemical identity of specific harmful pollutants in streams. ;In increasing trend for more specific and more sensitive procedures may be confident,ly predicted, both to supplant and to supplement the traditional procedures such as B.O.D., C.O.D., and odor. SUMMARY
During the nest 20 years, surface water resources n-ill become progressively scarcer. Their use as a means of disposal of liquid industrial waste discharges will be subject to continued reexamination in the interests of the total economy. There may be progressive restriction on the quality and quantity of liquid waste discharges. Intelligent control must be based on analytical methodology, which does not appear to be developing a8 fast ns the control problem with which it, is confronted. Present trends or future needs in the use of techniques for the analysis of industrial w s t e s are: Instrumentation to measure and record m a t e quality Increasing use of bioassay procedures t,o control the suitability of water for fish Increasing need and pressure for examination of wastes for material toxic to man
1821
Development of ne\v parameters of pollution for changing patterns of water use and changing nature of waste discharges Further modification of the traditional analytical procedures borrowed from the field of sewage disposal and water plant operation to adapt them to better use in the examination of industrial wastes Increasingly specific n-aste analysis to pinpoint problems in waste control and to serve as the basis for research on waste properties and their effects in streams. LITERATURE CITED
Aril. Public Health ; l s ~ ~ c . . ,Sely York, “Standard Methods for the Examination of Water, Sewage, and Industrial K a s t e s , ” 10th ed., 1955 Braus, Harry, Xfiddleton, F. AI., Walton, Graham., ANAL. CHEM.23, 1160 (1951). Cleary, E. J., Seuage and I n d . Wastes 26, 203 (1954). Doudoroff. Peter. Purdue Universitv Eneineerinlr Extension “ I Bull. 76, 88 (1951). Doudoroff, Peter, Katz, Max, Sewage and I n d . Wastes 25, 802 (1953). Doudoroff, Peter, and others, Ibid., 23, 1380 (1951). Ettinger, 31. B . , I d . E/LQ. Chem. 48, 256 (1956). Ettinger, &I. B., Sewage and I n d . Waafes 28, 1116 (1956). Ettinger, 31. B., Water and Sewage Works 97, 292-4 (1950). Gellmen, J., Heukelekian. H., Sewage and I n d . Wastes 27, 793 (1955). Hollis, AI. D . , Publ. Health Repts. 71,436 (1956). Kaufman, S., Water and Sewage Works 10, 302 (1954). Kieselbach, R . , AXAL.CHEM.26, 1312 (1954). Levine, H . S., Warren, K.V., Tnivoglou, E. C‘., Kalker, W.IT., Ibid., 28, 343 (1956). Ludsack, F. J., Whitfield, C . E . , Ibid., 28, 157 (1956). McKenzie, H. A , , \Tallace, H . S., Australian J . C‘hem. 7, 55 (1954). Manufacturing Chemists’ Association, Washington 6, D.C., “Chemical Industry Facts Book,” 2nd ed., 1955. hIiddleton. F. 11..Grant. 1Tallac.e. Rosen. A. h..I n d . Ena. Chenz. 48, 268 (1956). Mills, E. J., Stack, I-.T., I t i d . , 48, 260 (1956). Mills, E. J., Stack. T. T., Sewage and Ind V a s t m - 27, 1061 (1955). Moore, W.d.,Rurhhoft. C. C., Ibid., 23, 705 (1951). A s . 4 ~ CHEX. . 28, 164 (1956). Moore, W.A., Walker. W .W., Rluers, hI. N., J . SOC.Chem. I n d . 5 5 , 71T (1936). Orford, H. E., Rand, 11. C., Gellmen, E’., Sewage and I n d . Wastes 25, 2S5 (1953). Sallee, E. lI.,and associates, -4x-a~. CHEM.28, 1822 (1956). Salvesen, J. R . , I n d . T a s t e s 1, 87 (1956). Sawyer, C. K.,Bogan, R . H., Simpson, J. R . , Ind. Eng. Chem. 48, 236 (1956). Secretary, Department of Health, Education and TTelfare, statement before Subcommittee on Flood Control, Rivers, and Harbors, Senate Committee on Public Works, April 22, 1955. U. S. Dept. Commerce, Xational Bureau of Standards, Handbook 52, “Alaximum Permissible Amounts of Radioisotopes in t h e Human Bodv and Maximum Permissible Concentrations in Air and Water.” Wilson, T. S., private communication. Yiseman, J. IT., Sewage and I n d . Wastes 27, 1284 (1955). 1
RECEIVKD for review August 8, 1556.
.4ccepted September 2 6 , 1956
