Safeguards for groundwater Aquifers are fragile water resources whose properties are markedly different f r o m those of surface water. They supply many human needs. Their protection is vital, so tight rules about monitoring them, and keeping contaminants out, are coming. ES&T’s Julian Josephson surveys this situation Groundwater-about 50% of the U.S. population, or more than 110 million people, are dependent upon it for drinking, cooking, washing, industrial, agricultural, and many other uses. It comprises approximately 95% of the U.S. freshwater supply. Moreover, in many areas, especially arid ones, people may be absolutely dependent upon this resource. Understandably enough, then, groundwater protection is a matter of national and, indeed, worldwide concern. Protection from what? From contaminants, particularly inorganic and organic chemicals that can originate from human activity, as well as pathogenic organisms. In the U.S., at least, the need for groundwater protection has been a stimulus for the passage of the Safe Drinking Water Act of 1974 (SDWA), the Resource Conservation and Recovery Act of 1976 (RCRA), other pertinent legislation, both federal and state, and regulations pursuant thereto. Some regulations are already 38 Environmental Science 8 Technology
“on the books”, others are still in various stages of preparation. Slow attenuation Before going into any discussion of regulatory and technical strategies for protecting groundwater, it might be useful to examine this vital resource itself. First of all, one generally speaks of groundwater as being water in the saturation zone, which could, for example, be recovered through a well. Its natural quality can vary from fresh and immediately potable to brackish, saline, alkaline, or other classifications. Some imagine groundwater to consist of streams that move beneath the ground, much as brooks, creeks, or rivers move on the earth’s surface. In certain rare cases, this may happen, but most groundwater moves through its zones slowly-perhaps 5-500 ft/y, depending upon the geological media through which it moves. Its movement is governed by water recharge rates,
geologic medium permeability, water table gradient, and certain other factors. The flow, if any, is essentially laminar. This is one main reason why naturally occurring solutes and manmade contaminants would persist in groundwater, why their attenuation could sometimes be exceedingly slow, and why they are normally not subject to dilution in this water. The hydrodynamic forces of flow which would be conducive to solute or contaminant dilution are essentially absent. Another factor conducive to longterm contaminant persistence is the general lack of contact between groundwater in situ and air, a t least below the aeration zone, where thickness varies with geological conditions. This absence of air can lead to the groundwater’s being a contaminant preservation medium, because: Dissolved metals and nonmetals may be in reduced oxidation states because of the very oxygen-poor environment.
Conditions for decomposition of organic contaminants through contact with atmospheric oxygen or aerobic biodegradation are absent; this applies especially to aromatic organics. Natural chemical or physical means by which inorganic contaminants may be neutralized or insolubilized, or by which organic contaminants can be decomposed, or volatile contaminants removed, are generally lacking. In essence, then, contaminants which find their way to a groundwater horizon have virtually no “natural antidotes”, and no place to go. Regulatory strategies Because contaminated groundwater would be exceedingly difficult, if not impossible, to clean up after the fact, the most expedient approach to groundwater protection would be to prevent contaminants from reaching it in the first place. This prevention is one of the main regulatory thrusts of SDWA, R C R A , and other applicable federal, state, and local laws. Present man-made sources of groundwater contamination are many and varied. They might consist of pesticides indiscriminately applied, improperly secured chemical waste sites, some underground injection wells; land-disposed municipal, industrial, and agricultural wastes, or mining tailings and wastes. Contaminants may enter an aquifer directly or in the form of leachates. One example of a regulatory strategy to keep contaminants from reaching groundwater zones is found in provisions of R C R A governing land-filling of hazardous wastes at properly lined, secured sites. Applicable regulations are expected to “hit the street” by April 30, as things presently stand. Another example is the underground injection control (UIC) program, called for under SDWA. To implement that law, U I C “reg” proposals (reproposals, actually) appeared in the Federal Register, Vol. 44, No. 78, April 20, 1979, pp 23 7 3 8-23767 ; the comment period closed August 20. Final rules are expected early this month. Another threat to groundwater may arise from surface impoundments of municipal, industrial, and agricultural wastewater in pit ponds, lagoons, and other such facilities. As of June 1978, it was estimated that at least 132 700 such sites existed in the U S . , of which 75% were industrial, 15% were agricultural, and 10% were municipal. Many were (and probably still are) unlined and underlain by permeable soils, so potential for seepage of con-
taminants of all kinds, some highly toxic, is there. Under the authority of SDWA, to obtain an idea of what the groundwater threat really is, EPA initiated the S I A (surface impoundment assessment evaluation system). It got under way in 1978, and was funded to the extent of $5 million. Presumably, knowledge and data gleaned from the S I A will lead to a surface impoundment regulatory strategy vis-2-vis groundwater protection. Disposal alternatives After April 30, as R C R A regulations come into place (assuming no further time slippage), if a waste is declared hazardous, and the plan is to dispose that waste to land, this disposal will be governed by some very strict rules. Among them will be provisions for containment in the landfill in such a manner that they may in no way contaminate surface or groundwater, surrounding soil, or air.
What is a hazardous waste? In Section 1004 of RCRA, a hazardous waste is defined as “a solid waste, or combination of solid wastes which, because of its quantity, concentration, or physical, chemical, or infectious characteristics may: cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible illness, and pose a substantial present or potential hazard to human health or the environment when improperlytreated, stored, transported, disposed of, or otherwise managed.” Liquid and contained gaseous wastes and sludges are also covered under this definition (Section 1004, No. 26A and 27). Examples of hazardous wastes are those which are: infectious or pathogenic, corrosive, ignitable, reactive, bioaccumulative, carcinogeniclmutageniciteratogenic, toxic, or persistent. When these types of wastes encounter groundwater, they might dissolve, or form a second phase, if they are liquid and immiscible with water. Alternatively, they can be carried to groundwater in leachates.
Some who may be affected by these regulations have been heard to complain that they are much tougher than is really necessary for cost-effective protection of these resources. Whether their complaints are justified or not, there may be a philosophy behind this strictness: to make methods of managing hazardous wastes which do not involve disposal to land more attractive economically than those which do involve that method. Requirements for landfill design will be very stringent and, among other things, will call for impermeable disposal site linings, such as special clays, proprietary materials ( E S & T , July 1975, p 622), or, maybe, plastics. But there have been doubts expressed as to how the impermeability of these materials may stand up under actual fill conditions; perhaps, the thought in certain regulatory quarters is that even the most minute risk of lining failure is unacceptable. After all, if a lining fails, groundwater risks being exposed, however slightly, to invasion by wastes and leachates. Some alternatives to land disposal of hazardous wastes could be: incineration, chemical detoxification or neutralization to nonhazardous materials, and subsequent safe disposal, recovery/puriFcation of the waste in the same, or a new form, and recycling to a plant process, biodegradation where possible. Whether this R C R A regulatory philosophy will be uniform is. hard to predict. After all, it is EPA’s hope that states will take over these R C R A regulatory functions. Burnell Vincent of EPA’s Office of Solid Waste estimated that 47 states would seek this primacy. Some state regulatory bodies may have concepts concerning land disposal that are somewhat different from those at EPA, and could put them into practice if they are granted primacy. Nevertheless, the rules will be sufficiently tight so that not too much variation in enforcement strategies should be possible. A recent conference Vincent spoke a t a conference, “Benefitting from Environmental Monitoring”, held at Arlington, Va., in late October. It was sponsored by Geraghty & Miller ( G & M , Syosset, N.Y.), and American Ecology Services, Inc. (New York, N.Y.). More than 200 people attended. Geraghty & Miller is engaged in consulting on groundwater and matters generally related to groundwater, its monitoring, and its protection. It was founded in 1957. Another firm Volume 14, Number 1, January 1980
39
that has recently announced the availability of extensive groundwater consulting services is The Research Corporation of New England (Wethersfield, Conn.). Presumably there are others. David Miller, principal and senior vice president of G & M , coordinated the conference. H e explained that one objective was to show how complete groundwater monitoring and recordkeeping pursuant to R C R A could protect a waste disposer in situations in which a violation has occurred, but may have resulted from more than one industrial activity in the area of a given aquifer, for example. Other conference aims were to discuss monitoring techniques, laboratory methods and certification, case histories, and other closely related topics. Incidentally, Miller won last year’s National Water Well Association ( N W W A ) President’s Award. Located in Worthington, Ohio, the N W W A is the national groundwater industry “spokesman” and information clearinghouse (ES& T , March 1976, p 227). Jay Lehr is its executive director. Suits, comments, delays Actually, hazardous waste management regulations pursuant to R C R A were supposed to have been “on the books” by mid-1978. When they did not appear, various environmental advocacy organizations and the State of Illinois filed suit against the EPA in the U S . District Court for the District of Columbia. Judge Gerhard Gesell of that court ordered that the hazardous waste regulations be promulgated by the end of last year. T h e regulation-making process normally calls for a public comment period, and R C R A hazardous waste “reg” proposals were no exception. There came 1200 sets of public comments, some as long as 1500 pages! They comprised a stack of paper more than seven feet high. Most dealt with RCRA Subtitle C, “Hazardous Waste Management”. One can well imagine the manhours of work needed to wade through all of those technical comments, but it had to be done. Indeed, many of the comments, plus new information received, were “sufficiently noteworthy”, as EPA administrator Douglas Costle put it, to induce the agency to reconsider and repropose-or partially repropose-some of the regulations. Especially affected were “regs” under Sections 3001 (Identification and listing of hazardous waste) and 3004 (Standards applicable to owners and operators of hazardous waste treat40
Environmental Science & Technology
G&M Vice President Miller NWWA award winner
ment, storage, and disposal facilities). In an affidavit to Judge Gesell, Costle explained that the comment/ reproposal process was much more time-consuming than originally foreseen. That is why he predicted that the “regs” would come out “in late winter or early spring.” After April 30, perhaps 275 000 waste generators and 30 000 facilities, not to mention 10000 (estimated) waste transporters, will be affected. Their approximate timetable for compliance would be as follows: By July, EPA or the state, if accorded primacy, must be informed of
A monitoring well
Note Depths In feet: well operates In both upper and lower permeable zones Source: Harza Englneermg Co (Chlcago. Ill.)
all hazardous waste generators, facilities, and transporters. By October, a t least an “abbreviated” site permit application must be submitted, in order that a facility qualify for “interim status”. Also by October, monitoring must begin after EPA (or the state) is notified that a facility will handle hazardous wastes. Theoretically, by October 15next January is a more likely starting date-all facilities in violation must be inventoried and reported; it is estimated that 18 000 mixed municipal and 75 000 industrial sites may fall into that category. Disposal facilities presently operating will be allowed to apply for permits, and thus to continue “until EPA gets around to them,” Vincent told the G & M conference. Presumably this permission will not extend to any facility found to constitute an imminent hazard. Where to monitor When the time comes that monitoring is required, there will probably be certain rules, guidelines, and recommendations as to how to monitor. For example, where to place monitoring wells for groundwater, how to construct and complete them, and how, what, and where to sample would be covered. Such systematic monitoring of groundwater provides a way of knowing whether or not a hazardous disposal site is properly secured and operating legally. At the G & M conference, a question was raised as to whether monitoring wells would be placed at the limits of the property owned or leased by a site operator, or at the actual site limits. In other words, if the property owned or leased by the operator constitutes, say, 15 acres, but hazardous wastes are secured in only five of those acres, would the wells surround the entire 15 acres, or just the five acres where actual disposal occurs? What was heard at the conference suggested that the latter loca’tion will be mandated. How deep must such wells be? Presumably, they must monitor any aquifer horizon from which water for human needs, especially potable needs, may be taken. Such aquifers can vary in depth from near the surface to perhaps several hundred feet. In any case, the well must extend down into the proper saturation zone. Keep the air out One who must sample groundwater from monitoring wells will find that it is not simply a question of pumping water to the surface and field and
“lab-testing” it. G&M Senior Scientist O h Braids advised that it would be well to bear in mind that groundwater is in a quite different geochemical state from that of surface water, largely because of the fact that the ground itself normally separates groundwater from atmospheric air. It follows, then, that sampling must be done in such a way as to minimize or, better, to eliminate sample contact with atmospheric air, so as to keep the sample representative of the medium from which it was drawn. One reason
is because materials in the sample may be in reduced oxidation states. Now at the point where groundwater meets the well, there would probably be contact with air, so much water must be purged from the sampler, and water which did not contact air must be drawn in. It is possible to procure custommade equipment, of stainless steel or plastic, for instance, which can perform this purging function a t monitoring wells. For wells less than 20-25 ft deep, a peristaltic pump, whose
rollers force fluid through a sampling tube, is one type of equipment. There are other approaches for wells 25 ft deep or more, such as submersible pumps. Leonard Mold and Die (Denver, Colo.) is one maker of this sort of equipment; most likely, there are other firms in the business. Monitoring/sampling materials
All monitoring/sampling equipment should be made of materials inert to the suspected contaminants. For this reason, polyvinyl chloride (PVC) pip-
Monitoring wells and their problems HWMF = Hazardous waste management facility
c
Recharge area Leakv wastewater Dond
Land s u r f a c e
Uncontaminatedwater
Ei ---- --------- ------------Aquifer
H
d
~--__I_---
Source: Geraghty & Miller, Inc -ect
Confining beds
-c--
to dtlution by the natural groundwater
Avoiding certain monitoring errors It is of utmost importance to obtain representative groundwater samples while monitoring wells are being drilled. These samples should cover the entire thickness of the aquifer. Results obtained will act as guides as to the depths at which the wells should be screened-that is, where the casing should be perforated, or otherwise made able to take in well samples. If sampling while drilling is not done carefully, certain errors in monitoring well placement and construction can arise: A well such as Well A taps a contaminated aquifer, but takes water from below the contamination plume. Well B takes samples from above the contamination plume.
Well D is screened for the entire aquifer thickness; thus, it samples contaminants along with so much clean water that spurious contaminant dilutions are reported. Normally, monitoring wells are placed between a disposal site and a natural discharge point, such as a marsh or stream, down the topographic slope from the disposal site. But suppose that, very near to, though “upstream” of the disposal site, there is a pumping well-perhaps, one whose function is to provide process water for a plant. The flow of contaminants in the groundwater will be toward that pumping well, so: The downslope monitoring wells will detect no contaminants, since they are diverted from their normal flow path. The contaminants might be able to be monitored through the pumping or production well, so in this case,
the monitoring wells may be superf Iuous. Here is another possibility: A confining bed of impermeable material can separate an upper and a lower aquifer from each other. Perhaps the upper aquifer is susceptible to contamination and the lower is not. Nevertheless, errors, such as drilling the monitoring well too deep and screening it for the lower aquifer, do occur. In yet another situation, certain liquid contaminants might be found in phases other than aqueous. They can be lighter (oils) or heavier (certain organics, for example). Their possible presence should be determined through sampling while drilling monitoring wells. Otherwise, such wells, while functioning properly in detecting contaminants dissolved in water, will miss the contaminants in other phases. Source: Geraghty & Miller, Inc.
Volume 14, Number 1, January 1980 41
ing is normally acceptable. However, PVC stops being acceptable if it is believed that aromatic organic contaminants are in the sample, since these aromatics could react with PVC. PVC is also unacceptable in equipment or piping if organic contaminants suspected to be in the sample are in a phase separate from water. In any event, never use PVC glue to put piping or casing together. Use pressure fittings, or heavy “Schedule-80’’ PVC with threads. Copper should not be a constituent of equipment and piping if ammonia is suspected of being in the samples to be taken. Also, if piping or casing must be of iron or stainless steel, steam-clean everything before lowering it into the well. This procedure removes all traces of oil and grease. Wash out all thread cutting oil with hexane. Preferably, put couplings together with Teflon@tape. If these precautions are not taken, spurious readouts for organics will
result. Moreover, rust on iron pipe will adsorb organics from the sample, so if concentrations of organics are very low, 5-10 volumes of water should be purged before samples are drawn. Reduced states Because groundwater is usually an oxygen-poor medium, elements such as iron, manganese, and sulfur can be expected to be in reduced states. Different mineral equilibria, pH situations, dissolved oxygen counts-the last normally very low-from those of surface water are encountered. Moreover, in contaminated surface water, considerably more carbon dioxide and methane may frequently, though by no means always, occur. There could be other peculiarities. In a way, the reducing nature of groundwater could help to find a “labeling” substance (or substances) that could indicate whether or not a given aquifer is susceptible to leachate con-
tamination. G&M’s Braids proposed iron and manganese in their reduced states; both could be readily leached from waste sites or from natural sources, and thus serve as indicators. These reduced-state elements, as well as certain organic substances in a groundwater sample, could be altered or destroyed if that sample came into contact with air, as it must a t some point in time. For this, and other reasons, it is recommended that after a sample representative of groundwater conditions in situ has been properly drawn, field readings of temperature, pH, conductivity, and any other possible data points be immediately obtained. Later, results can be confirmed in the laboratory. Lab reliability and fees Anyone who is subject to groundwater monitoring/sampling/analysis “regs” under RCRA, SDWA, or other such laws should avail himself of the
A project in Poland
Jacek Libicki of Poltegor testing surface mining effects Can the US. profit from the experience of groundwater monitoring in western Poland? The U.S. EPAespecially Region 3 (Philadelphia, Pa.)-must think so, because it has contributed funds and effort to the project. The work involved determining effects of coal mining waste and power plant ash, disposed to land, on groundwater. The project was (and still is) carried out by Poltegor {Wrocfaw, Poland), that country’s research organization for opencast (surface) mining. Jacek Libicki, Poltegor’s chief geologist, told €S&Tthat the aim was to find out how aquifer shape was being affected, and what was leaching into groundwater. Data obtained were put into computer-readable language.
42
Environmental Science & Technology
The project began in the early 1970’s and is still ongoing. Poltegor may have been the first group anywhere to engage in this type of effort. It was started because Poland, as part of its plan to expand its own energy supplies, wanted to increase opencast coal mining activity. A large portion of this activity is taking place in fairly heavily populated areas of southern and western Poland, which are industrialized in many places, and yet, where groundwater is often used for drinking and agricultural purposes. Parallel situations could exist in the US.: both countries seek improved ways to protect groundwater from opencast mining effects, thus this cooperative project. In one trial that Libicki described, an area about 40 m by 20 m was covered with material consisting of 70% coal refuse and 30% power plant ash. This material was placed in an open pit and was about 2 m thick, and 1500 m3 in volume. The pit’s bottom was sand, 1.5-2.0 m thick, whose filtration coefficient was around 50 m/d. The water table was “a few cm” below the surface of the sand. Over two years, sampling was done from 12 wells in and around the refuse pile, with analyses every three weeks. Maximum groundwater contamination occurred after seven months, particularly after a period of heavy precipltation. There were increases in a
number of contaminants’ concentrations: for example, potassium went from 2.0 to 40 mg/L: copper, 0.003-0.2 mg/L: cadmium, 0.0020.005 mg/L: and cyanides, 0.0020.008 mg/L. Libicki said that no increases in aluminum, chromium, iron, or manganese occurred; for lead, mercury, and zinc, an increase was “doubtful.” The most significant increases were boron, from 0.2 to 2.0 mg/L; chlorides, 10-400 mg/L: and sulfates, 100-900 mg/L. The higher values for these conbminantsexceededPolishdrinking water standards by 100%, 150%, and 600%, respectively. The total weight of contaminants @achedfrom the pile was approximately 11 500 kg, Libicki said. That constituted 0.7% of its entire bulk, and 70% of all leachable substances. About 90% of the contaminants migrated “downgrade”, topographically, along the water table: the balance spread out in other directions. So that both Poland and the U.S.can profit from such data, and use it to enhance groundwater protection in opencast mining areas in their respective nations, the two countries hold joint seminars on this topic. The first was held in Denver in 1975,and the second in Poland in September
1978. Larger-scale trials are now under way.
services of a laboratory of high reputation and quality, which is also EPAor state-certified. This quality and certification might cost more than would the services of a noncertified laboratory, to be sure. But data from a certified laboratory would be of higher credibility, in the event that the client finds himself involved in a “difference of opinion” with a regulatory agency, says Albert Kupiec, president of Penn Environmental Consultants, Inc. (Pittsburgh, Pa.). What might such costs be? For example, suppose a groundwater sample was believed to contain phenol, and a distillation/extraction/analysis to a 0.001-mg/L detection limit was required once a month. In that case, the volume of each sample would be 500 mL. The method of preservation would call for phosphoric acid pH adjustment to 4, addition of 1 g / L of copper sulfate, and cooling to 4 OC. A typical fee would be $25-35 per analysis. By comparison, perhaps a gas chromatograph/mass “spec” scan for hydrocarbons, organophosphates, pesticides, and PCB’s is required by EPA “regs”. The detection limit would be 1 y g / L . The scan would cost $45-95. In addition, each such item found, with PCB’s reported as one item if more than one PCB type is found, would carry a fee of $45-95. These fees were quoted by Kupiec for the EPA-certified lab for drinking water that his company has, but they are probably typical for the whole industry.
PCB’s dissolve, too The idea of a lab having to analyze for PCB’s and other such compounds in groundwater may not be as farfetched as it might seem a t first. Supposedly, PCB’s and numerous other organics do not dissolve in water, but actually, a PCB such as “Aroclor 1254” can dissolve in water to the extent of 0.044 mg/L at 25 “ C . Moreover, benzene can concentrate in water to 1780 mg/L, also a t 25 “C, chloroform, to 9300 mg/L, and phenol to as much as 82 000 m g / L , at that same temperature. These and other substances could find their way to groundwater because of improper disposal in the past, or illegal dumping “under cover of night”, for example. And once they have reached the groundwater, they can persist for a very long time-for certain aromatics, half-lives of as much as 10 000 years have been estimated. The oxygen-poor nature and slow movement of most groundwater helps to account for this great contaminant persistence, especially below the
aeration zone, as does the general lack of biodegradation potential. But contaminant persistence and mobility vary. For instance, chelated metals are more mobile in groundwater than are, say, aromatics. O n the inorganic side, cations attenuate more easily than anions. Overall, contaminant mobility depends upon oxidation-reduction potential, complementary ions, and the presence of clays or hydrous oxides in earth materials, G&M’s Braids explained. Moreover, heavy metal ions could be slowed down because of a greater tendency to form complexes than alkali and alkaline earth metal ions have. If field and lab tests find groundwater to be contaminated chemically-proper disinfection should handle the pathogens, if any-can that situation be reversed? Attempts to do so have met with mixed success. Injecting chemical solutions is futile, since the chemicals will not mix with groundwater. Pumping, to change hydraulic head relationships, prevent escape of contaminants, or to intercept contaminants should usually work. However, problems with this latter approach will include treatment of pumped groundwater or discharge of untreated groundwater, as well as the long time necessary for such operations. For the future, exposure to air to induce biodegradation or sorption by some method, reverse osmosis, ion exchange, and similar approaches, may also show promise, though they could be somewhat costly. In any event, most technology for decontamination of groundwater is apparently “slim pickins” for the time being.
Disposal wells Aside from improper chemical and other waste disposal sites, another threat to groundwater resources exists in underground injection wells. Control of these wells is to be addressed partly by R C R A , but principally by the S D W A , especially Part C of the latter Act, which mandates protection of underground sources of drinking water. One person who keeps tabs on this drinking water source is Thomas Belk of EPA’s Office of Drinking Water (ODW). He is chief of ODW’s Groundwater Protection Branch. As of last April, there were more than 500 000 municipal, industrial, commercial, agricultural, and domestic wells injecting fluids below the surface. At least 5000 new wells are being added each year. Part C of S D W A is aimed a t underground injection control (UIC), to ensure that this disposal method does not endanger
EPA’s Belkcontrols on injection wells
drinking water sources. While S D W A addresses underground injection much more than R C R A does, R C R A will mandate-90 days after its “regs” are final-that anyone disposing of wastes in this manner must report this fact to EPA. And, under SDWA, regulations pertaining to U I C may be in force by the time this report appears, since December 1979 or January 1980 were target dates. Injection wells are divided into Classes I-V (see box). Wells of Classes 1-111 will come under rigid permit requirements. As for Class IV, existing injection wells will be inventoried. EPA or the states will have to formulate enforcement policies that would close existing Class IV wells within three years after hazardous wastes
Injection well classification according to SDWA Class I includes industrial and municipal disposal wells, and nuclear storage and disposal wells that inject below all underground sources of drinking water in the area. ludes all injection wells ith oit/gas storage and production. Class H I includes all special process injection wells; for example, those involved itl solution mining of minerals, in situ gasificationof coal or oil shale, and other such activities: and the recovery of geothermal energy. Class IV includes wells used by generators of hazardouswastes, or by hazardous waste management facilities, and which inject info or above underground sources of drinking water. Class V includes at1 other injection wells. Source: Federal Register, Vol. 44, No. 78, p 23740, April 20, 1979.
Volume 14, Number 1 , January 1980
43
“regs” under R C R A go into effect, and prohibit new ones. Class V wells would be considered and strictly permitted (or forbidden) on a case-bycase basis. As of April, total UIC regulation costs were estimated at $808 million (1 977 dollars). Belk told ES&T that a permitted Class I injection well, “properly” sited, contracted, and operated, will inject below the deepest freshwater aquifer zone. “I can’t give you a specific well depth,” he said, “but 2000-3000 ft are
good figures of merit. Each one would cost $250 000- 1 million, depending upon actual depth, hazardous waste types, and other factors.” Surface impoundment As mentioned earlier, surface impoundments of wastewater, both municipal and industrial, may constitute a threat to groundwater. For this reason, in 1978, EPA set up the SIA evaluation system. It involves six principal steps:
Maximum Limits 01 Impurities Total Organ,c Carbon (1 I Total Trihalomethanes (21
1 I Method UltraViolet promoted cnemical oxidation
conversion lo methane. flame ionization detect on
chlorodibromomethane
+
bromod~cnloromethane
J 1.Baker Chemical Co PhiliilJ’.utrrg N J 0 >Ht 5
CIRCLE 11 ON READER SERVICE CARD
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Environmental Science & Technology
rating the unsaturated zone-the zone above the water table-through which wastewater, or a leachate, can migrate downward to the water table, rating groundwater availability, rating groundwater quality, rating the hazardous waste potential, rating the overall groundwater contamination potential (previous four steps), and rating and potential danger to groundwater supplies. S I A data will represent a “firstround approximation”. Precise measurements of water table depth, earth materials underlying impoundment sites, site hydrogeology, and other factors involved, in all 50 states and seven territories, would be extremely costly and time-consuming. This ongoing program applies to pit ponds, lagoons, and other such wastewater treatment/disposal installations, Belk told ES&T.
An indispensi ble job Since groundwater normally does not have the capability that most surface water has to attenuate contaminants, what is the best way to protect it? Prevention is the key; contaminants must not get into groundwater in the first place. Perhaps the best way to achieve this aim would be to manage wastes in such a way that their treatment/transportation/disposal involves means other than landfilling, surface impoundment, underground injection, and the like. Since this total no-fill, no-inject approach is probably unrealistic for the time being, EPA’s alternative will be the strictest regulation of these land-based techniques. But how would one know whether or not technical and regulatory means of protecting groundwater were successful? After all, once contamination shows up, protective efforts have failed, and the damage is done. In addition, imagine the amount of work and expense involved if all groundwater under U S . jurisdiction were to be just‘inventoried, monitored, and evaluated, to say nothing of being totally protected, and, if necessary (and possible), decontaminated. On the other hand, as said before, at least 50% of the U S . population depends upon groundwater. Moreover, a far greater portion of the population in arid areas, both in the U S . and abroad, depend almost entirely upon subterranean water resources. Surely, then, a very large amount of funds and effort would have to be expended, worldwide, to do the indispensible job of safeguarding these vital resources.
