Effluent monitoring step by step A tiered approach, using chemical and biological indicators, could increase effectiveness and efficiency, and save time and money Dean R. Branson, David N. Armentrout, William M. Parker, Clayton Van Hall Dow Chemical U.S.A. Midland, Mich. 48640 Larry 1. Bone* Dow Chemical U.S.A. Texas Diuision, B-I 031 Freeport, Tex. 77541 The technology to improve water quality and the public’s interest in protecting water quality have increased significantly over the past IO years. Indications that this interest will continue to increase for the next few years include speculation that nonspecific conventional pollutant controls may not protect water from overexposure to some specific chemicals, more advanced analytical and toxicological methods, and the consent decree, which led to the identification of “129 priority pollutants.” These factors have led some public policymakers to believe that “total chemical accountability” is both feasible and necessary ( I ) . In addition, biomonitoring has been suggested as an extra precaution beyond frequent and extensive mass spectrometric monitoring for chemicals in effluents (2.3). Some have even suggested adding biomonitoring requirements to enforceable violation limits ( 4 , 5 ) . However, while biomonitoring results and other nonspecific indicators of chemicals can be used to justify needs for specific quantitative chemical analysis, the latter provides the only scientifically sound basis for enforceable violation limits ( 6 ) . The tier concept A compliance monitoring program for effluents that is based on various tiers of chemical and biological tests has been devised to maximize water quality protection and minimize 0013-936X/81/0915-0513$01.25/0 @,I981 American Chemical Society
monitoring costs. The first tier of tests should signal all situations that may jeopardize water quality and indicate any need for more definitive and specific chemical tests. Such chemical tests would either help to identify a specific problem or rule out the existence of an actual environmental threat. This approach has been used in other environmental areas (7-11) and is not very different from a physician’s approach to monitoring human health Simple screening tests are performed during periodic physical examinations, which either indicate good health or signal the need for more extensive diagnosis. If the diagnostic scheme is well-conceived, the number of tiers of tests required should relate to the severity of the malady. Common ailments should be diagnosed quickly, far short of exploratory surgery, but the physician must design screening tests that are reasonably certain to detect most ailments. Flexibility and innovation are fundamental to the tier concept. These features are critical to any successful national policy for effluent monitoring, particularly for the chemical industry, because each effluent-receiving water body is unique and calls for case-bycase monitoring requirements. Also, as new, more cost-effective monitoring methods are developed and validated, they should be implemented as soon as possible. Specifically, it is proposed that each effluent monitoring program would blend frequedt, simple, and inexpensive tests that signal potential environmental harm with less frequent tests that are more complex, more expensive, and more definitive; each would blend biological and chemical tests and would be tailored to the characteristics of the effluent and receiving water. The tier concept employs simple tests on a frequent basis, Volume 15. Number 5. May 1981 513
more difficult tests when indicated. Violations would be documented and major corrective action taken only when definitive tests show that a permissible exposure limit has been exceeded. One important consideration in selecting suitable indicator tests is that they should be reasonably certain to detect potentially hazardous conditions. The disadvantage of this approach, however, is the number of false positive indications that must be ruled out by tests at higher tiers. Biological tests are good indicators
depending on the sp
of some types of environmental threats ( 1 2 . 1 3 ) but are not good for locating the cause of the environmental problem, since dose-response relationships for specific chemicals have not been established for aquatic organisms exposed to complex effluents. Locating the source of the problem is essential if corrective action is to be taken. A “Chinese menu” Table 1 is an attempt to assemble these tests into a “Chinese menu,” on which the various levels are characterized by the difficulty and chemical
4-AAP BO&
However, some tests are subjective ed with dher test r e d s pior to
Many of the screening tests can in some cases continuously with
’
specificity of each test. An effluent monitoring program would then be selected, much like ordering from a Chinese menu, by picking one or more tests from each level. Selection of a suitable combination of tests involves a careful matching of needs with resources. This match-up includes a consideration of the types of pollutants discharged, probable concentration ranges, uses of the receiving water, and availability of analytical equipment and personnel. If a particular discharge contains only a few pollutants, a complex series
4-Aminoanfipyrine. A colorimetric method for phenols. Automated instruments available. Sio/ogica/oxygen demand. Simulates the biological activity of the receiving body and the effect of wastewater upon it. Flvehy test. c measurement of me ,
Provides a measure of
en compounds by means of pypurchased a s fully automated moni
TURB
rurbidify. A M U which can indicate
rolysis arid coulometric measurement of the
is. Measures volatile
A method for sepads. Followed by uitra-
methcd for separating
chmmto@apby. A means of separating measuring inorganic arid organic cations anions by ion exchange. Followed by conductimetric measurement.
514
Environmental Sclence 8 Technology
are also important to this tier concept of effluent monitoring. Typically, the tests in the first tier are nonspecific screening tests, while the successive tiers are more definitive. Ideally, if the first-tier tests indicate compliance, then no further testing is necessary. But good quality assurance prescribes that tests at all levels, including the definitive tests, should be conducted periodically, regardless of the results of the earlier tiers.
TABLE 1 Effluent monitoring tests Chemlcal tests
Blological tests
Indicator tests: low degree of difficulty and interpretation Level A DO, TURB, COND, Color, pH, TOD, TOC, UV
FISH 02, BIOLUM, COUGH, SCHOOL
Indicator tests: intermediate degree of difficulty Level B
Static 24-h LC50, static 96-h LC50
COD, 4-AAP, BOD5, TOX, TON, TOS, AA
Tier-concept application The process of preparing a typical tier monitoring program for an industrial effluent would follow several steps. First, in order to characterize the effluent and receiving water, a list of che,micals and their expected range of concentrations in the effluent would be prepared. The receiving water into which the effluent will flow would be classified according to its use and existing levels of chemicals. Then, various concentration limitations would be placed on the effluent to maintain the desired water quality. Next, representatives of the discharger and permitting authority would agree on indicator tests to assure that concentration limitations are not exceeded. Selection of the action levels for the indicator tests should be based on site-specific data generated from field studies. These data must include an evaluation of the relationship between proposed, measurable pollution indicators and adverse effects to receiving water. That is, in addition to simple chronic and acute effects on aquatic life, one must consider such things as photosynthesis rate, diversity of species, bioconcentration, and so on. An appropriate action level for an indicator test would then be set as a fraction of the level known to have caused any harm to that receiving water; this fraction would be the margin of safety. Table 2 contains two possible sets of tests for one simple and one complex
Indicator tests: high degree of difficulty Level C
VOA, LC, GC, IC, AA
FT-96-h LC50 SURVEY parameters
Definitive test: high degree of difficulty and specificity Level D
Specific chemical analysis with a validated analytical method (such as GUMS)
of tests would make no sense. However, effluents with a larger variety of possible pollutants would probably be handled by a tier scheme with frequently performed indicator tests. These indicator tests should be selected to assure detection of the most hazardous chemicals in the effluent, that is, those chemicals with narrow margins of safety between the concentration normally in the effluent and the water quality standard. Then, if the effluent contains chemicals that could be present at concentrations carcinogenic to humans, special monitoring techniques that are not as adaptable to the tier concept may be required. However, it should be noted that most of these techniques are beyond the state of the art at this time. The possible concentration swings that are expected in some effluents should also be considered. If concentration variations occur frequently, some carefully selected fast-feedback tests would be more desirable than slower, more precise tests that do not allow time for taking corrective action. The designated use of the receiving water is also important in selecting a suitable effluent monitoring program. For example, tests designed to protect marine life are more appropriate for monitoring effluents discharged into saltwater than are tests designed to protect drinking water. Similarly, frequent measurements of BOD, acute fish toxicity, and the like are probably a waste of time if the real hazard of the specific effluent to the water quality is a risk of human cancer via bioconcentration in aquatic life. Finally, different dischargers may
prefer to use different instruments to monitor the same type of effluentreceiving water because of differences in the complexities of their respective operations. For instance, some large industries might prefer to use sophisticated instrumentation such as gas chromatography/mass spectrometry (GC/MS) for relatively frequent chemical analysis. This procedure, of course, would be entirely impractical for most smaller industries. The best interest of the public would be served by selecting suitable effluent monitoring programs under which the discharger and the permit writer, working together, consider each of the important factors already described. Otherwise, a predetermined matrix of tests indiscriminately applied to monitoring effluents would result only in wasted effort and inadequate protection of the environment. Such schemes may be easy to write and enforce, but will not protect public health. The principles of quality assurance TABLE 2
Alternate schemes for the same simple or complex effluents
Effluent
Number of indlcator tests Level B
Level A
Simple
Chem
Bio
Chem
Bio
A A’
2 0
0 1
2 1
0 0
5 4
0 1
8 5
0 5
Detlnltlve ~. tests Level D
Level C
Chem
Total
Bio
Chem
1 1
0 0
I 1
6
18 8
0 5
5 5
36 33
4
Complex B B’
Note: Programs A and B contain no biomonitoring
Volume 15,Number 5,May 1981 515
effluent. Since both effluents could contain chemicals at biologically significant concentrations, monitoring will be necessary to protect the reiving water. Suppose the critical chemicals in the simple effluent were metal ions. One discharger (A) might find that screening with conductivity and ion chromatography provides practical and reliable indicators of overexposure, whereas another discharger (A’) may find screening with a fish bioassay to be equally reliable, but more practical to conduct. Both options would be acceptable for screening this simple effluent. In both cases, the definitive test would quantitatively measure the concentration of the specific metal ions according to a validated analytical method, such as atomic absorption.
Similarly, for the complex effluent, the critical chemicals may be metal ions, trihalomethanes, sugars, chloroanisoles, and chlorobiphenyls. There are many equivalent combinations of chemical and biological tests that could be employed for screening, but the limits would be based on definitive chemical tests such as GC/MS. Once there is agreement on an appropriate set of tests to monitor particular effluents, the analytical chemist and biologist must verify that the tests can give reliable results for their particular effluent. From the validation results, precision and accuracy of each test can be defined. These accuracy and precision data will be of prime importance when apparent noncompliance situations arise. In addition to thorough validation
studies, an adequate quality assurance program must be established to ensure continuing accuracy of the effluent monitoring results. This program would include, among other things, instrument performance checks, standardizations, blank controls, fortified samples, and duplicate runs at regular intervals. All of these must b, well-documented and available fa inspection. Test timing Figure 1 shows how the tier monitoring program can be used to determine compliance and noncompliance of a particular effluent. In this case, the agreement calls for five specific Level A tests to be run daily; three Level B tests to be run weekly; four level C tests to be performed monthly;
and three Level D tests to be done quarterly. Each test would be described with its expected accuracy, precision, and useful range specified. For the period shown in Figure 1, the magnitude of each test result does not reach the preset action level or permitted level. Consider, however, a situation in which some Level A test result, with its attendent precision limit (2 u or 95% confidence), just bare' exceeds the permitted level. Then tt test is repeated at least twice toverii, the result before an action is taken, Suppose subsequent analyses indicate that the permitted level has not been exceeded, and the program outlined in Figure 1 continues for some arbitrary time, say six months, with no violations. It would then be logical for the regulatory agency and the industry to agree, for example, that a particular Level B test need only be run once a month, instead of weekly, as previously defined. This reward of less frequent analysis will provide the incentive for careful control of the effluent stream composition. By the same token, this system should encourage experimentation with new testing techniques, including their addition to the tier scheme when properly validated. What happens when a permitted level of some test is exceeded by an amount beyond the precision limits of the test? Figure 2 describes a logical series of steps when this occurs. Assume that an upset occurs and the results for A3 (maybe TOD) and A5 (color) are too high. If these values are reproduced a second time, then the Level B tests, including BI (UV absorbance) and 8 3 (a heavy-metals colorimetric test), would be run. If these results also exceed their action levels, it would be necessary to do the C and D tests to determine the source of the upset. If the Level D test results exceed the action level, it then would be necessary to report a possible violation to the permitting authorities. To illustrate the case further, Figure 2 indicates that the C3 test result lies high above specifications. This test might be an atomic absorbance measurement of dissolved copper. The copper has apparently inhibited biological activity in the treatment plant, so the effluent contains only partially treated wastes. Quickly, a program would be established to discover the source of the copper and halt its release. While the C tests are being run, several D tests would also be required to prove that more than one upset has not occurred. Even if the problem is solved on the third day of the cycle, Figure 2 shows it is still necessary to perform all the tests again on Day 4 to
FIGURE 1
R ~ S U I ~of S an effluent monitoring program': all values within the action lwds 1st Wednesday of -ich month
Monday of each week
Daily
2nd Wednesday of each quarter
L A
J T h e length d the line for each test shows the concentration in that sample for that time. A line' extending outside the circle is exceeding the action level.
FIGURE 2
Resultsof an effluent monitoringprogramexampleof noncompliance
L
A
Day 4
Day 5
-
A
Volume 15. Number 5, May 1981 517
demonstrate recovery of the treatment plant. Repeated violations of a B, C, or D test would require measurements to be made more often than originally agreed upon. Simplification. innovation The tier concept developed logically from the dilemma created by contradictory views that effluent violations can and should only be based on definitive chemical analysis, but that these definitive tests are too difficult and expensive to be performed on a daily basis. The concept has not yet been applied to effluent monitoring. Nevertheless, experience suggests that there is a reliable matrix of good indicator tests that should signal any environmental problem. To be sure, many of the simple indicators, particularly the biological ones, can give false indications. If this were not so, indicator tests obviously would be sufficient to assume good environmental protection. I t is a challenge to the entire environmental community to develop simple, reliable tests of water quality that give a minimum of false indications. With the expanding technology base. sufficient screening tests are available to allow construction of a monitoring program for any effluent that will assure adequate environmental protection and optimum costeffectiveness. Acknowledgment Before publication, this article was read and commented on for appropriateness and suitability as a n ES&T feature article b y Dr. Robert L. J o k y of the O a k Ridge N a t i o n a l Laboratory. O a k Ridge, Tenn.: Dr. R i c h a r d A. Kimerle of Monsanto. St.
Louis. Mo.; Dr. James E. N o r r i s of CibaGeigy Corporation, McIntosh. Ala.; and Dr. Herbert E. Allen of the Illinois Institute of Technology. Chicago. 111.
References (I)EPA.“NPDES: Proposed RevisionofEx-
isling Regulatians”a) Fcderol Regisrw 1978, A u t . 31. 37078. b) Federal Rqirrer 1979, June I d . 34393. (2) Cross. F. L.:Garrity. R. D. Poll. Eng. 1978, ?7
R. B. Cumming. Eda.: Ann Arbor Scicncc: Ann Arbor. Mich. 1980.Vol. 3. pp.949-59. (9) Epler. J. L.: Winton. W.: Hardigree. A. A.: Larimer. F. W. “Thc Appropriate Use of Cenctic Toxicology in Industry”: H. Witchi. Ed.; Elrevier North Holland Biomedical PreSs: Amsterdam. The Netherlands. 1980 pp. 45-49. ( I O ) Guerin. M. R.“The lntcgrntcd Approach to Chemical-Biological Analysis”: Sccond Sympasium on Process Mearurcments for Environmental Assessment: Atlanta. Ga.. Fcb. 25-27, 1980. (II) Dickson. K. L., ct 81. “Criteria and Rationale for Decision Making in Aquatic Halard Evaluation”; J. Cairns. K. L. Dickson, and A. W. Maki. Eds.: ASTM: Philadelphia. 1978. pp. 242-273. (12) Spmgue. J. B.: Rowe. D. W.: West1ake.C. F.: Hcming. T. A,: Brown. I.T. “Sublethal Effects of Treated Liquid Effluent from a Pctroleum Refinery on Freshwater Organisms”: Report to Petroleum Association for Conservation of the Canadian Environment: October 1978. (13) Orians. G . H.(Chairman ofan Ad Hoc Study Group). “Goals ofand Criteria for Design o f a Biological Monitoring System”: EPA Scientific Advisory Board Report: January 1980. (14) “ M e t h d far Chemical Analysis of Water and Wastes;” EPA-600/4-79-020 March
lyzing ihe Hazard Asscssmcnt P;ocess”:
pp.
D(Jx.’.v Health mid Enuironmental Sciences Ri,.Tearch Laboratories (Midland). H e (16) Buelich. A. A.:Greene. M. W.: Isenberg, ho1d.T a B.S. from the Unicersity of KedD. L. “The Reliability of the Bacterial Lumilands, Coli/.. and received a Ph.D./rom nescence Assay for the Detcrmination o f Montano Srare Uniuersiry in 1967. His Toxicity of Pure Compounds and Complex Effluents”: 4th A S T M Aqudtic Toxicology research interests include hazard assessSymposium: August 1979. ment o/chemicals in the aquatic enoiron(17) Gruber.D.;Cairnn.J..Jr.:Dickson.K.L.: ment. Hendricks. A. C.: Miller, W. R. 111. “An Automated Biological Monitoring Facility for William M. Parker (1. ), a senior enoironRapidly and Continuously Assessing Industrial mental biologist with Daw (Midland), has Effluents”, 3rd A S T M Aquatic Toxicology 10 years experience in thefield o/eIfluent Symposium: October 1978. biomonitoring. including baseline sumeys, (18) Maki.A. W.“MonitoringAbcrrant Rcspiratory Activity of Blucgill as a Predictor of e//luent impact studies, fieldwork assoChronic Fish Toxicity Values of Surfactants”: ciated with storm modeling, design a/ 3rd ASTM Aquatic Toxicology Symposium. flow-through acute and chronic toxicity October 1978. equipment. and operation o/ in-situ (19) Drummond, R. A,: Carlson, R. W.. hionionitoring .stations. “Procedures for Measuring Cough (Gill Purge) Rates of Fish”: EPA R e w r t 60013-77-133: December 1979. (20) Warner. M . C.; Randall. W. F.: Johnson. E. I.:Braich. S. G . “Thc Residual Oxygen Bioassay: Are Threshold Values Comparable to 96-Hour Static LCsds?”: Unpublishcd U.S. Army Report. Ft. Detick, Md.. 1978. (21) Williams. B. R. H. Chem. Ind. 1974, Feh. 1.07-7,.
(22) ORSANCO. “24-Hour Bioassay”deve1oped by the Biological Water Quality Committee. Ohio River Valley Water Sanitation Commission, Cincinnati, Ohio, January
(3) EPA. “Rcmarkr b) Sandra Gardebring. C S . EPA Repion V: Scminrr on R ~ u l u ~ i c ~ l Uonilorine and 11s Use m the I\PDL.S Prrmii Program.”-Chicagol 111. Oct. 2. 1979. (4) EPA, “Biomonitoring Protocol Guidance for the NPDES Permit Program.” Draft May I. 1978. _.., ...i. (5) EPA “Interim NPDES Compliance (25) Shumway. D. L.: Palensky.“lmpairment Biomanitoring Inspection Manual.” October of the Flavor o f Fish by Water Pollutants”: 1979. EPA Report R3-73.010 February 1973. (6) Daw Chemical Company, “Comments on (26) Tesmer. M. T.: Wefring. D. R. “Annual Proposed NPDES Regulations.” Scptember Macroinvertebrate Sampling-A Low Cost , ,. Tool for Ecological Assessment o f Effluent Leidel. N. A,; Bush. K. A,: Lynch. J. R. Impact”: Unpublished D a w oresenled at an A < T M mertinn Occupational Exposure Sampling Strategy ~,IO,!? Manual”, H E W report; January 1977. (27) Weber, C. 1. “Biological Field and Labo(8) ratory Methods for Measuring theQualityaf . . Maki. A. W. “Desien and Conduct of Hazard Evaluation Prog;ams for the Aquatic Surface Water and Effluents”: EPA R e w r t Environment”; R. L. Joky, W. A. Brungs. and 6/014-73-001: July 1973 ~
(7)
~~~~~~~~~
,I
518 Environmental Science 8 Technology
Dean R. Branson (1.) is o group Ieoder in
101-111.
I”,”
_I
David N. Arrnentrout has ill years o/experimce in rhc Enrironmenral Analysis group or Dow Chemical Company ( M i d land. Mich.). where he has specialized in the analysis o/rrace organics in warer. H e has a B.S./rom the Unioersity o/ Kansas and a Ph.D. in analyrical chemistry/rom Cornel1 Unicersity.
...__....
Clayton Van H a l l (1.) is an associate sci-
enrist in the 1~nvironmental Analysis Group o j t h e Analytical Laboratories a/ Dow (Midland). H e holds a B.A. /ram Hope College and a Ph.D./rom Michigan Srare Unioersity. His research interests are the development of analytical merhods/or trace organics in water and wastewater.
Larry 1. Bone (1.) is in charge o/the Deuelopmenr Laborafory, Environmental Seroices, Daw Chemical Company, Freeport. r e x . H e holds a 8 . A . j r o m Coe College, Iowa. and o Ph.D./rom Ohio Srare Unioersity. H e has 20 years o/experience in physical, analytical, and environmental chemistry with academia, gouernment, and industry.
