&EPA United States Environmental Protection Agency Office of Drinking Water Washington DC 20460 Criteria & Standards Division State Programs Division May 1979 WSG 61 Water Guidance for the Issuance of Variances and Exemptions ------- TABLE OF CONTENTS Preface i Section I: Conditions for Granting Variances and Exemptions Section II: "Economic Factors for Granting Exemptions," Guidelines for Determination Section III: "Unreasonable Risk to Health," Guidelines for Determination A. Bacteriological III-2 B. Turbidity III-2 C. Inorganic Chemicals III-3 1. Arsenic III-3 2. Barium III-5 3. Cadmium III-7 4. Chromium III-9 5. Fluoride Ill-10 6. Lead III-12 7. Mercury. 111-14 8. Nitrate III-1 6 9. Selenium 111-19 10. Silver 111-20 D. Organic Compounds 111-21 1. 2,4-D 111-21 2. 2,4,5-TP 111-24 3. Toxaphene 111-27 4. Methoxychlor 111-29 5. Endrin 111-31 6. Lindane 111-33 ------- 2 E • Radionuclides................................. .111—36 1. Combined Radium—226 and Radium—228........III—36 2. Gross Alpha Particle Activity.............III—38 3. Man—Made Beta and Photon Emitters.........III—39 Section IV: Variance and Exemption Procedures Section V: Compliance Agreements ------- GUIDANCE FOR THE ISSUANCE OF VARIANCES AND EXEMPTIONS PREFACE This document contains guidance for the issuance of variances and exemptions under Sections 1415 and 11416 of the Safe Drinking Water Act, as amended (142 U.S.C. § 300 f et s q.) and the regulations implementing those provisionsTSee 1FO CFR Section 1141.14). This guidance is intended to be used by States with primary enforcement responsibility (primacy) and EPA Regional Offices that issue variances and exemptions in those States that have not been granted primacy. For the purpose of this document, they will be collectively referred to as the “primacy agency.” Variances and exemptions are authorized to be issued by a primacy agency to a public water system that is not immediately able to comply with a maximum contaminant level (MCL) or treatment technique requirement established in the National Interim Primary Drinking Water Regulations (NIPDWR). No variances or exemptions may be granted from monitoring requirements under the NIPDWR. The NIPDWR presently in effect, 140 CFR Part 1141, specify MCLs for a number of contaminants including turbidity, microbiological contaminants, inorganic and organic chemicals, and radionu- clides. They do not presently prescribe any treatment techniques which are also authorized under Section 11412 of the Act. Therefore, this document will be limited to a discussion of variances and exemptions from MCLs prescribed under the NIPDWR. A separate guidance will be issued for variances and exemptions from a treatment technique should one be prescribed in any amendment to the NIPDWR. In providing the primacy agency with the authority to issue variances and exemptions from the NIPDWR, Congress recognized that not all public water systems would be able to achieve compliance with the regulation by the effective date. It was assumed that two different kinds of problems would be encountered by public water systems required to comply with the NIPDWR, and variances and exemptions were intended to address these problems separately. First, a public water system might be unable to achieve compliance with an applicable MCL due to poor source water quality, despite application of the most effective treatment methods. In such rare situations, the primacy agency would be authorized to grant a variance to that public water system. 1 ------- The second, and more common situation, would be where the public water supply was unable to comply with an applicable MCL due to compelling factors such as economic constraints which may include the high cost of purchasing and constructing necessary equipment or facilities and/or the low per capita income and small number of residents in a community served by the system. The granting of an exemption would be authorized under these latter circumstances. The distinction between variances and exemptions is important for two reasons. First, new systems are only eligible to apply for a variance. Before an exemption may be granted, Section 1416(a) (2) of the Act requires that the primacy agency find that “the public water system was in operation on the effective date” of any MCL or treatment technique requirement. Thus, Congress intended that compelling factors, such as economics, would not be used to enable a new system to commence operation without first being in full compliance with the applicable requirements. On the other hand, a variance could still be appropriate where a new system is unable to comply with the effective regulations despite the application of best technology due to poor source water quality. The distinction between variances and exemptions is also important because of the different compliance time tables established by Congress. Both variances and exemptions must be accompanied by the issuance of a compliance schedule within one year. The compliance schedule must require that the public water system come into compliance with the appli- cable MCL as expeditiously as practicable (as determined by the primacy agency). Whereas the compliance schedule for an exemption requires compliance by no later than January 1, 1981, (or January 1, 1983, if a public water system has entered into an enforceable agreement to become part of a regional public water system), no such statutory deadline is imposed for variances. A variance is issued to a public water system whose source water is of such poor quality that it may not be possible to dictate when technology will become generally available to bring that system into compliance. Therefore, it may not be possible to set a compliance deadline for such a system. However, Congress intended that an exemption specify a time limit for compliance on the assumption that compelling factors such as economic hardship could be miti- gated over a period of time. EPA recognizes the problems 11 ------- which the exemption deadlines may pose particularly to small water systems, and accordingly is asking Congress to extend the time limit for exemptions. In the interim, compliance schedules for exemptions must attempt to achieve compliance in the shortest possible time and may not extend longer than the statutory deadline. However, this schedule may reflect a review date at which time the primacy agency can revise the deadlines should the statute be amended. Variances and exemptions were not intended to be used as means for easily or indefinitely delaying compliance with the NIPDWR. Congress specifically required the primacy agency to make the finding that the issuance of either a variance or exemption would not result in an unreasonable risk to the health of the persons served by the system. In addition, the public water system is required to give public notification pursuant to Section 1 1 (c) of the Act of the existence of each variance or exemption and any failure to comply with the requirements of any compliance schedule issued therewith. The compliance schedule itself must contain interim control measures and increments of progress to be followed by the public water system while such variance or exemption is in effect. Any requirement of a schedule on which a variance or exemption is conditioned may be enforced as if such requirement were a part of a NIPDWR. In return for the public water system’s compliance with these requirements, the issuance of a variance or exemption to a public water system otherwise in violation of an MCL under the NIPDWR, protects that system from enforcement action under Section i 14 as well as from “citizen suits” under Section 1 9 of the Act. Finally, under Section 1 4 8(b) of the SDWA, the granting of, or the refusing to grant a variance or exemption, the requirements of any schedule for a variance or exemption and the failure to prescribe a schedule are subject to judicial review in the United States district courts. EPA also com- prehensively reviews State—issued variances and exemptions at best every three years to assure that the State has not abused its discretion in granting variances and exemptions and has not failed to impose reasonable control measures. For purposes of these reviews, it is critical that the primacy agency carefully document the bases for its deter mi nat i o n. This document is intended to assist in the development of uniform interpretations and protocols for issuance of variances and exemptions and for application of the NIPDWR. It will also serve as the basis for EPA ’s review of State—issued variances and exemptions. 1].]. ------- This guidance for granting variances and exemptions will discuss the following issues in turn: I. Conditions for Granting Variances and Exemptions — This section will discuss the fundamental conditions for the granting of variances and exemptions from MCLs. II. Economic Criteria for Granting Exemptions - One criterion for granting an exemption is the existence of compelling economic hardship. This section discusses the specific procedures for making a determination as to whether “compelling economic factors” exist to justify the granting of an exemption. III. Unreasonable Risk to Health - The granting of a variance or exemption from an MCL must not result in an unreasonable risk to the health of consumers served by the public water system. This section will provide guidance that may be used in making this determination. IV. Variance and Exemption Procedures - The procedures that must be followed by States in granting variances and exemptions are set forth under Section 1 l15 and 1416 of the Act and O CFR Part 1 42 Subpart C. kO CFR 1112.kO and § 142.50 set forth procedures to be followed by EPA where it retains primary enforcement responsibility. This section will discuss these procedures, generally providing flow diagrams as an aid to understanding. The issuance of compliance schedules will be discussed in detail. V. Compliance Agreements — This section discusses an administrative tool that can be used in certain situations where it would be impractical to fully implement the exemp- tion process. Guidance is given on procedures to implement this administrative tool. iv ------- SECTION I CONDITIONS FOR GRANTING VARIANCES AND EXEMPTIONS Variances from MCLs Section 1’ 15(a)(1)(A) of the Safe Drinking Water Act authorizes the primacy agency to grant variances from MCLs to public water systems which: because of characteristics of the raw water sources which are reasonably available to the systems, cannot meet the requirements respecting the MCLs of such drinking water regulation despite application of the best technology, treatment techniques, or other means, which the Administrator finds are generally available (taking costs into consideration.) (Emphasis added). In addition, the primacy agency must make a finding before the variances may be granted that the variances will not result in an unreasonable risk to health. The language of this section as well as the legislative history make clear that the essential basis for the granting of a variance to a public water system is the quality of the raw water sources reasonably available to that system. Under Section 1L 12 of the Act, Congress intended for MCLs under the NIPDWR to be established at such levels which could be achieved by large systems with relatively uncontam- inated raw water sources. Congress explained its rationale for this assumption as follows: If the Administrator were to assume that intake waters would in general be extremely contaminated, then many areas which are relatively clean could meet the maximum contaminant levels which the Administrator would prescribe without the use of the most effective treatment methods. This result would be inconsistent with the Committee’s overriding intent to maximize protection of the public health. (House Report No. 93—1185, p. 12). However, Congress also recognized that, in some instances, public water systems with extremely contaminated intake water sources would be unable to comply with the MCLs even after installing the technology determined by the Administrator to be generally available when the MCLs were ------- 1—2 established. Variances were therefore authorized to be granted in such cases. To qualify for a variance from an MCL, a public water system must demonstrate to the primary agency that it satis- fies the following two conditions: 1. The application of treatment methods, generally available at a reasonable cost to large systems, has not esulted in compliance with the MCL due to poor source water guality, and the system has made all other reasonable tech- nological, economic and legal efforts to comply with the MCL . It is important to note that the system must have the “generally available” treatment in place and operational in order to demonstrate that non—compliance is due to poor source water quality and thereby to be eligible for a variance. In addition, the primacy agency should ensure that the system has made all reasonable efforts to obtain access to an alternative, less contaminated raw water source. The system may be able to improve its raw water quality through identification and elimination of the cause of contamination. Reasonable technological solutions such as improvement of existing treatment operation and efficiency should also be explored. The primacy agency should periodically review variances after they are issued to assure that they are still necessary and that all reasonable efforts to obtain access to a satisfactory raw water source are being made by the system. (See also discussion of compliance schedules under Section IV of this document). 2. Issuance of the variance will not result in an unreasonable risk to health . The determination of whether or not the issuance of a variance will result in an unreasonable risk to the health of consumers served by the system must take into account the nature of the contaminant and the degree of contamination in a particular case. Guidance for making this determination is contained in Section III of this document. * Variances are expected to be granted relatively infrequently since available treatment methods should ordinarily be effective. See EPA ’s Manual of Treatment Techniques for Meeting the Interim Primary Drinking Water Regulations. This manual lists treatment methods for specific contaminants for which MCLs have been established in the National Interim Primary Drinking Water Regulations. ------- 1—3 Exemptions from MCLs Section 1416(a) of the Safe Drinking Water Act authorizes the primacy agency to grant an exemption from an MCL based upon a finding that: (1) due to compelling factors (which may include economic factors), the public water system is unable to comply with such contaminant level, (2) the public water system was in operation on the effective date of such contaminant level, and (3) the granting of an exemption will not result in an unreasonable risk to health. Congress recognized that some public water systems would not be able to achieve compliance with the MCLs by the effective date of the regulations. Because the MCLs were established based upon technology reasonably available to large systems, it was anticipated that small systems might experience particular hardship in meeting the standards. (See House Report No. 93—1185, p. 18). In order to provide systems faced with problems related to economic and techno- logical feasibility more time to achieve compliance, exemptions were authorized to be granted. However, specific time deadlines were imposed by the Act by which time such systems were required to be in compliance. (See discussion of compliance schedules in Section IV of this document). In addition, the Act imposed the following three conditions for the granting of an exemption by the primacy agency: 1. The system is unable to comply with an MCL due to economic or other compelling factors . The existence of compelling factors is the principal criterion for determining whether a public water system should be granted an exemption. Such compelling factors are most likely to be economic factors, such as not being able to afford the treatment necessary to achieve compliance with the MCL. This could be because of the high cost of purchas- ing and constructing and operating necessary equipment or facilities, or the low per capita income and small number of residents in a community served by the system. The system might also encounter unavoidable delays or other technological problems in installation or operation of the necessary treatment equipment which would prevent a system from achieving compliance by the effective date of the MCL. ------- I— 4 The primacy agency should exercise its exemption authority in a responsible manner, especially if a system would be forced to terminate service in the absence of an exemption. However, it is also essential during the period of the exemption, that the system be required to find solutions to its problems such as the development of a regional water system which could afford to purchase and operate the necessary treatment technology, to seek additional sources of funding such as State or Federal financial assistance, and to explore alternative raw water supplies. The compliance schedule issued by the primacy agency should incorporate those steps which the system must take to meet the MCLs. (See Section IV of this document). More detailed guidance on the economic factors that should be considered by the primacy agency in determining whether to grant an exemption is contained in Section II of this document. As a basic principle, however, Congress expected public water systems to use available funds to achieve compliance with the MCLs rather than for substantial expansion of capacity or service. Thus, the House Report stated: In the Committee’s view, if a system has sufficient funds to permit substantial expansion of capacity and service, these funds should first be used to assure the safe quality of the drinking water presently being supplied. In such cases, States should be extremely reluctant to grant exemptions on economic grounds. (House Report No. 93-1185, p. 27). 2. The system must have been in operation when the applicable MCL went into effect . This condition basically prohibits the primacy agency from granting an exemption to a new system, that is, a system which begins operation after the effective date of the regulation. This was clearly intended to require all new systems to be in compliance with all applicable require- ments before they became operational. This is consistent with Congress’ expressed reluctance to grant exemptions on economic grounds where the substantial expansion of’ existing facilities of a system are planned. 3. Granting of the exemption will not result in an unreasonable risk to hea11 h . The determination of whether or not the granting of an exemption will result in an unreasonable risk to the health ------- 1—5 of consumers served by the system must take into account the nature of the contaminant and the degree of contamination in a particular case. Guidance for making this determination is contained in Section III of this document. ------- SECTION II “Economic Factors for Granting Exemptions” Guidelines for Determination One of the prerequisites to granting an exemption to a public water system is that the primacy agency make a finding that the public water system is unable, due to compelling factors, including economic factors, to comply with an established maximum contaminant level. The decisions which lead to this finding are indicated in the attached Diagram A and constitute the areas where the primacy agency will have to apply case by case analysis. Each is discussed below. 1. Is there a significant risk to health ? Handled on an individual MCL basis, guidance on this decision is contained in Section III. 2. Is the addition of the necessary treatment the best alternative for the system ? Treatment alternatives are discussed in several documents, including “State of the Art of Small Water Treatment Systems” (August 1977) and “Estimating Costs for Water Treatment as a Function of Size and Treatment Plant Efficiency” (EPA—600/2—78—182, August 1978). In many cases the most desirable alternative will be the least costly alternative, including consideration of alter- native water sources. However, other factors such as water quality parameters, quantity needs, and personnel requirements must also be considered. The water supplier making application for an exemption should indicate alternatives considered, and reasons for his selection. For small water supplies, Regions and States can be expected to provide technical assistance in the evaluation of the alternatives which might be used. 3. Are the financial constraints to system implementation of the best alternatives due to political, legal or technical obstacles ? There are legitimate financial constraints which may be due to political, legal or technical reasons. ------- I 1—2 Political obstacles which impose real financial constraints tend to include the inability to pass bond referenda, or other capital raising activities which require voter approval, and dependence upon water revenues for non—water public services. Such obstacles do not immediately justify the issuance of an exemption. For communities which must develop new funding to replace water revenues for other community services when water revenues are used to upgrade the water supply facility, it is expected that an appropriate compliance schedule would consider the community’s public service commitments as well as its water supply needs. Evidence of either kind of obstacle should be presented with the application for exemption. Legal obstacles tend to revolve around changes in local charters or time consuming approval requirements associated with capital or revenue—raising activities. An adequate description of these constraints could affect a system’s compliance schedule. For example, if amendments to existing ordinances must be made prior to implementing the changes that will bring the system into compliance, the exemption compliance schedule should include a reasonable time necessary to draft, propose, hold public hearings and pass amendments in addition to the time required to get necessary fundings and complete the construction or modification. Occasionally, the water supply or municipality may be under legal challenge to halt or alter proposed improve- ments to its water supply (including rate changes). It may be desirable for the primacy agency to investigate the desirability of filing briefs on behalf of one party or the other. In any case, such an obstacle to system improvement may have financial considerations which could reasonably warrant an exemption. Technical obstacles tend to dissolve if sufficient capital and operating revenue is generated, and as such are not prohibitive constraints. However, on rare occasions, extreme conditions impose virtually prohibitive situations. For example, analysis of upstream discharges may be extreme— ly expensive yet control at that point of upstream discharge may be the best alternative for compliance. As such, there may be occasions when a compliance schedule must reflect these special circumstances. 1 L Has the system investigated all possible sources of funds ? The Federal financial aid programs are described in the “Catalog of Federal Domestic Assistance.” Some States also provide grants and loans to public water systems. ------- II— 3 Applicants should demonstrate that they have investi- gated these sources of funding when applying for an exemption. 5. Will system customers undergo financial hardships ? Assessment of financial hardship requires some basic kinds of information. Systems should provide data on (a) annual capital requirements, (b) annual O&M requirements, (c) annual revenue requirements associated with system improvement for compliance, (d) financing opportunities (in dollars available), Ce) system indebtedness, U ’) number of outstanding unpaid bills as a percent of total bills, (g) old and new annual family water bills (based on 3 people per family) and (h) median family income for the service area. Based on this information, the primacy agency can determine if a supply can finance system improvements. Having determined that financing opportunities exist, the primacy agency must determine the hardship that such financing may pose on consumers. The level at which the water bill is determined to be an economic burden relative to median family income involves a critical policy decision. The basic criterion in use by most Federal agencies is that the annual water bill should not exceed a set percentage of the median family income. Figures from .7 percent to 2 percent have been used by various agencies. EPA uses 2 percent for its construction grants program. FmHA is currently considering changing its disputed 1 percent debt service guideline to a measure similar to the 2 percent total bill guideline. However, for areas where annual median family income is low, perhaps as low as $5500, even the 2 percent figure may be onerous. The Office of Drinking Water cannot specify an exact number, but believes that for communities with an annual median family income greater than about $8,000, the 2 percent figure does not constitute a hardship. Below that income level, serious consideration should be given to a lower number. This economic consideration is under review at the present time; this section will be revised upon completion of the review. General Guidance In all cases, it is the intent of Congress to improve the quality of drinking water, but not at the expense of closing down water supplies. Therefore, exemptions should be responsive to the actual situation that exists as docu- mented by evidence presented by a water supplier. Where ------- II— 4 there simply are no financing opportunities, compliance schedules should be written to encourage speedy development of needed resources. Where hardship exists, compliance schedules should be written to account for longer term improvements. Any compliance timetable must also, of course, take into account the health risk posed to consumers during the exemption period (See Section III of this document). In considering if economic factors are sufficiently compelling to warrant an exemption, consideration must be given to any planned expansion of existing facilities of the system. It was the view of the Congressional Committee, as stated in the House Report 93—1185, page 27, that “... if a system has sufficient funds to permit substantial expansion of capacity and service, these funds should first be used to assure the safe quality of’ the drinking water presently being supplied. In such cases, States should be extremely reluctant to grant exemptions on economic grounds.” This principle should be adhered to in making a decision on economic hardship. ------- SECTION III “UNREASONABLE RISK TO HEALTH” GUIDELINES FOR DETERMINATION In order to obtain a variance or an exemption from an MCL, a public water system must demonstrate that the variance or exemption will not result in an unreasonable risk to health. When the absence of an unreasonable risk to health has been or can be reasonably determined, variances or exemptions can be granted within the limitations recommended herein. For those cases where the MCL has been exceeded to a greater degree than provided for in this section, and for cases where there is doubt as to the reasonableness of the risk to health, the Office of Drinking Water should be consulted. An exemption committee within that Office will provide assistance in these cases, thus assuring national consistency in the interpretation of the phrase, “unreasonable risk to health. tl Any violation of an MCL, by definition, creates some increased risk to the public health . The pertinent issue, though, for purposes of’ granting variances or exemptions from an MCL is whether the resultant increased risk is adjudged to be unreasonable . In any determination of unreasonableness of risk, at least the following should be onsidered: (a) The degree to which the MCL is being or will be exceeded during the exemption or variance period and the adverse chronic or acute health effects resulting therefrom. (b) The duration of the requested variance or exemption (i.e., the longer the duration, the greater the risk). (c) Historical data (how long the problem has existed in the subject water supply) and whether any adverse effects attributable to water may have occurred. (d) The population exposed (i.e. particularly susceptible individuals such as the very young or old or infirm). 1 The references cited within this document can be found in the National Academy of Sciences Safe Drinking Water Committee Publication, “Drinking Water and Health, (1977).” More detailed discussion of the material contained herein can also be found in that publication. ------- 111—2 In order to minimize the risk to health after an exemption or a variance has been granted, it is expected that more stringent monitoring requirements, full utilization of the public notification provisions and special notification to physicians and susceptible individuals, increased health surveillance programs, and the provision of alternate water supplies for susceptible individuals, will be conditions to the variance or exemption as the particular circumstances warrant. A. Bacteriological The maximum contaminant levels for coliform bacteria are one per 100 milliliters as the arithmetic mean of all samples examined per month, with no more than five percent of the samples containing more than four coliform bacteria when the membrane filter technique is used; and when the fermentation tube technique is used, coliform bacteria may not be present in more than 10 percent of the portions in any month for 10 milliliter standard portions, or more than 60 percent for 100 milliliter standard portions. The Community Water Supply Study of 1969 indicated that problems could be expected in meeting the coliform standards. Seventeen percent (17%) of the systems failed to meet the MCL. Sixty-nine percent (69%) of those failures were from poorly protected and/or inadequately treated sources. The presence of coliform organisms is an indica- tion of the presence of fecal matter in the water and is a warning that pathogenic bacteria indigenous to the intestinal environment may also be present. The presence of any type of coliform organism, fecal or non-fecal, in treated water suggests either inadequate treatment or contamination after disinfection, and should not be tolerated above the MCL. Methods are readily available to alleviate either of those causes; therefore, no variance or exemption from the coliform MCLs may be granted . B. Turbidity The regulation states that the MCL for turbidity measured at an entry point into the distribution system is: (a) one turbidity unit (TU), as determined by a monthly average, except that five or fewer TU’s may be allowed if the supplier of water can demonstrate to the Agency with primary enforcement responsibility that the higher turbidity does not do any of the following: ------- 111—3 (1) interfere with disinfection; (2) prevent maintenance of an effective disinfectant agent throughout the distribution system; or, (3) interfere with microbiological determinations. (b) five TU’s based on an average for two consecutive days. As implied in the National Interim Primary Drinking Water Regulations there is a relationship between the level of turbidity and the effectiveness of the disinfection process. Permitting the turbidity level to exceed the MCL may present a risk to the health of the persons served by such a system. It is recognized that the degree of risk is related to the type and level of turbidity present (as well as other factors, i.e., water source, disinfection practice, type of treatment, pH, etc.). In some cases where an assessment of risk indicates that elevated turbidity levels can be demonstrated not to interfere with the disinfection process, and where the other conditions relating to the higher turbidity are met, exemptions may be given above 5 TU but the schedule for compliance should be kept to the shortest time necessary to correct the situation. Conventional coagulation and filtration methods are effective in reducing turbidity to below 1 TU. C. Inorganic Chemicals 1. Arsenic (0.05 mg/i) Occurrence Arsenic is widely distributed at low concentrations in the waters of the United States. In one study of selected minor elements in 728 samples of U.S. surface waters, the concentration of arsenic ranged from less than 10 ug to 1,100 ug/liter. A study by the United States Geological Survey of river waters revealed that the median concentration of arsenic was less than the lower limit of detection, but 22% of the samples had concentrations of 10—20 ug/liter. In this survey, except for local anomalies where arsenic concentrations could be traced to industrial sources, no major regional differences could be detected in average values or in percentage of contaminated samples. ------- 111—4 Health Effects The toxicity of arsenic compounds is extremely variable and depends on the species exposed, the other contaminants present, the formulation of the arsenical, the route of exposure, and the rate and duration of exposure. Although man is susceptible to arsenic poisoning, there is a wide variation in susceptibility to specific arsenic compounds. The lethal oral dose (acute toxicity) of the more toxic arsenic compounds (trivalent) in most test animal species appears to be 1—25 mg/kg of body weight (Goodman & Gilman, 1970), whereas the lethal dose for the less toxic compounds may range from 10—400 times this amount. There is no acceptable animal model for study of arsenic-induced cancer. Arsenic causes fetal death at high doses and malformations at lower exposures in hamsters, mice and rats. Bacterial systems have revealed that arsenic interferes with DNA repair (Rossman and Troll, 1978). The different forms of’ arsenic and its various contaminants which exist in the environment may account for differences in clinical manifestations between different localities. There is some epidemiological evidence from foreign studies (Chile and Taiwan) that high concentrations of arsenic in drinking water along with other active contami- nants may be associated with skin cancer; however, this effect has not been seen in American populations at high exposure levels. The NAS stated, “If’ the time factors for the development of cancer are shown to be reasonable then the current interim standard of 50 ug/liter may not provide an adequate margin of safety.” Treatment Several methods by which arsenic can be removed are coagulation and flocculation through adsorption of the arsenic on aluminum or ferric hydroxide particles; ion exchange using activated alumina; and lime coagulation, recarbonation and filtration. Guidance Since the current MCL may provide only a small margin of safety, and since arsenic and its contaminants have been possibly linked to cancer, exemptions only up to 100 ug/liter should be considered. The chronic effects of arsenic (nerve conduction velocity changes) do not clini- cally present themselves in the general population over time. However, the reversible sub—clinical effects may ------- 111—5 manifest themselves in susceptible populations. Therefore, only limited exposure (five years or less) does not present an imminent health hazard. Compliance schedules should provide for the early installation of treatment processes (or for alternate solutions.) Variances would not be appropriate since treatment is available to control arsenic to the MCL. 2. Barium (1 mg/l) Occurrence Barium occurs naturally in almost all surface waters. Finished water of public water systems frequently contains barium, at 1—172 ug/liter, with a mean of 28.6 ug/liter; 94% of the determinations made in the 100 largest U.S. cities were less than 100 ug/liter. All but two of 2,595 tap water samples were less than the interim standard (McCabe, 1970). With a tantalum liner insert, the barium detection limit of the flameless atomic absorption procedure can be improved from 10 ugh to 0.1 ugh (Renshaw, 1973). No vital metabolic function has yet been found for barium, although it is believed to be beneficial for rats and guinea pigs under specific dietary conditions (Underwood, 1971). Barium is highly toxic when soluble salts are ingested. Fatalities have occurred from mistaken use of a barium salt rodenticide. The fatal dose of barium chloride for man has been reported to be about 0.8—0.9 g, or 550—600 mg of barium (Sollman, 1957). Industrial exposure to barium oxide and sulfate dusts produces a benign pneumon000niosis called “baritosis. H Although barium poisoning is rare in industry, the potential from the more soluble forms is real. The American Conference of Governmental Industrial Hygienists set an airborne threshold limit value (TLV) for barium of 0.5 mg/rn 3 . The limit was based on several years of obser- vation of workers at Los Alainos exposed to barium nitrate. Health Effects Acute barium poisoning exerts a strong, prolonged stimulant action on all muscles, including cardiac and smooth muscle of the gastrointestinal tract and bladder. Barium is capable of causing nerve block (deNo, 1946) and in small or moderate doses produces a transient increase in blood pressure by vasoconstrict.ion (Gostev, 1944). ------- 111—6 There has been no determination of the chronic effects of barium administered repeatedly over a long period, either in food or drinking water. There has been a recent study (Brenniman, 1979) which suggests the possibility of higher risk of cardiovascular disease, however, reevaluation of the data base and methodology employed are underway at the present time. The drinking water MCL was derived from the 8—hour weighted maximum allowable concentration (TLV) in industrial air of 0.5 mg/rn 3 set by the American Conference of Govern- mental Industrial Hygienists. It was assumed that, with an 8—hour inhalation of 10 m 3 of air, the daily intake would be 5 mg of barium, of which 75% would be absorbed in the bloodstream. It was assumed that 90% transferred across the gastrointestinal tract after ingestion. Based on the above assumptions, it was reasoned that a concentration of about 2 mg/liter of water would be safe for adults. To provide added safety for more susceptible members of the population, such as children, a level of 1 mg/liter was recommended. There have been no long—range feeding studies to confirm the safety of this barium intake. In one recent preliminary study, groups of young adult rats of both sexes were exposed to 0, 10, 50, or 250 mg of barium as barium chloride in drinking water for 14, 8, or 13 weeks. No adverse effects related to barium ingestion were observed in food consumption, clinical signs, body weight, hematologic parameters, serum enzyme activities, serum ions, gross pathology, and histopathology. (Tardiff, et al., 1978). — Treatment Treatments to control barium concentrations include lime softening and ion exchange softening; however, it should be noted that the latter may also increase sodium ion concen- trations. Increased corrosion of the distribution system from soft water may also release heavy metals. Since effec- tive treatments are available, variances should not need to be granted. Gunce In the absence of more definitive data, exemptions may be considered for communities whose drinking water have barium concentrations up to two (2) mg/liter providing that no adverse health effects attributable to the drinking water ------- I II— 7 are discernible. The level of 2 mg/i barium in drinking water was calculated from the data (Reference Man) suggest- ing that adsorption of barium from the gastrointestinal tract in children is approximately 25% of ingested amounts. Therefore, a 10 kg child drinking 1 liter of water contain- ing 14 mg/l barium may absorb 1 ing of barium. Incorporation of an additional safety factor for high risk individuals reduces the recommendations to 2 mg/i. The conditions for granting an exemption should include measures taken to minimize barium levels as soon as feasible. These may include source selection, control of sources if possible, and installation of treatment. Public water systems whose barium concentration levels exceed 2 mg/i should develop a plan to survey and sample the high risk residents to monitor for blood pressure and CVD factors for that community versus non—high Barium communities. This monitoring should continue throughout the exemption period. The survey should also include a questionnaire which gathers information about the use of home water softening devices, including type of device and length of use. Public water systems whose barium concentration levels exceed the MCL should monitor the water supply at least quarterly for levels of barium and sodium (because of softening) at the tap. Physicians should also be notified using the licensure registry. Normal public notification is also required. The above survey data which provide a baseline for epidemiological investigations should be used by State health officials to determine if any observed health effect is relatable to water quality. Any finding of an adverse health effect attributable to elevated barium concentrations provides grounds for reconsideration or revocation of the exemption. 3. Cadmium (0.010 mg/i) Occurrence Cadmium is not known to be an essential or beneficial element. It has been found in 2—3% of U.S. surface waters, generally in concentrations not exceeding a few micrograms per liter because solubilities of cadmium carbonate and hydroxide are low at pH greater than 6. Only 0.1% of the supplies in the Community Water Supply Survey showed cadmium in excess of 10 ug/liter. In addition to its geological sources, cadmium enters water from the discharge of plating wastes and by corrosion of plumbing by soft aggressive water. Using the graphite furnace to atomize samples, the limit of detection iS 0.005 ug/liter (Paris, 1971). ------- 111—8 Food is the primary source of cadmium intake (Drinking Water and Health, 1977). Total daily intake from air, water, food and tobacco ranges from 110 ug/day for the rural nonsmoker on a low cadmium diet to 190 ug/day for the urban smoker on a high cadmium diet. Cigarette tobacco contains cadmium at about 1 ppm. Friberg (197k) has estimated that smoking one pack of cigarettes per day contributes 2—k ug of cadmium per day. Drinking water contributes only a small fraction (< 5%) to this total intake. Health Effects Chronic ingestion of cadmium levels greater than 100 ug/day, in combination with several other necessary predisposing factors, was found to be responsible for the onset of “Itai—Itai” disease in Japan (Friberg, et al. 1972). Dietary intakes of amounts in excess of a milligram per day are needed for appearance of acute toxicity. Major toxic effects are on the kidney (Friberg, et al. 192k; Nordberg, 1976); data indicate that the toxicity of cadmium is related to the zinc: calcium ratio within the organs. Therefore, zinc and calcium may be protective against cadmium intoxication. Persons deficient in these elements, and especially lactose—intolerant persons, (from school age and up) who are also likely to be calcium—deficient, may constitute a high-risk group relative to cadmium. Animal studies have shown cadmium to be possibly teratogenic in the rat at high doses (2—13 mg/kg). Cadmium has also been implicated as a factor in hypertension. (Schroeder, 1965). The renal cortex is considered to be the critical organ for accumulation of cadmium from low level dietary expo- sures, and the critical concentration for the renal cortex is approximately 200 ug/g of tissue net weight (Friberg, et al. 19711; Norberg, 1976). At greater concentrations, irreversible renal injury may occur (Drinking Water and Health, 1977). Treatment Treatment methods for reduction of levels of soluble forms of cadmium (chlorides, nitrates and sulfates) include lime softening and ferric sulfate coagulation at high pH. Coagulation and sedimentation is effective for removal of insoluble forms (carbonates and hydroxides). When the source of cadmium is corrosion of galvanized or plated plumbing pipe and fixtures, reduction of concentration can best be effected by pH adjustment or other corrosion control practices. ------- 111—9 Guidance Insufficient data are available for establishment of a suggested no adverse reaction level. However, consumption of two liters/day of water containing 10 ug/liter of cadmium would contribute about 20% of the normal total daily adult intake, which is 2.5 times more than smoking two packs of’ cigarettes daily. This level of ingestion (to the daily intake) was considered in the setting of’ the MCL. The toxic effects of cadmium and the economic factors relating to available treatment methods for the soluble forms of cadmium lead to the conclusion that exemptions should be considered for levels up to 0.02 mg/i only and for minimum time periods necessary to blend or stabilize waters to bring the levels down to the MCL of 0.01 mg/i or to institute necessary treatment processes. 14• Chromium (0.05 mg/i) Occur r en cc Durum and Haffty (1961) reported a range of concentra- tions for chromium in U.S. rivers of 0.7—8k ug/liter. Kopp and Kroner (1967) detected chromium in 2 .5% of the samples examined, with concentrations ranging from 1—112 ug/liter and averaging 9.7 ug/liter. In a study of surface and groundwater in Canada, all but two of 2 0 samples examined were below 50 ug/liter. In 197 4, a maximum dissolved chromium concentration of’ 31 0 ug/liter was recorded in water from the Pecos River, New Mexico; the Los Angeles River; and the Columbia River, Oregon (USGS, 19714). In a 1970 survey, 11 of 700 samples had chromium concentrations of’ 6—50 ug/liter, with none exceeding 50 ug/liter. Ackermann (1971) reported chromium concentrations below 5 ug/liter for 18 of’ 27 river stations in Illinois; the maximum was 50 ug/liter. Health Effects Although hexavalent chromium has long been recognized as a toxic substance, trivalent chromium is considered by most investigators to be relatively innocuous and even (in microgram amounts) essential to human health. The chronic adverse effects most often considered in chromium toxicity are respiratory and dermatologic. ------- 111—10 With regard to carcinogenicity, intraosseous, intra—muscular, subcutaneous, intrapleural, and intraperi— tonel injections of chromium compounds have been reported to cause the development of sarcomas in rabbits, mice and rats. There is some evidence that chromium chloride in the form of a pellet attached to the bronchial mucosa in the rat lung may be carcinogenic, but there is no support for the view that it constitutes a carcinogenic hazard in human food (Sunderman, 1971). An IARC working group (1973) concluded “there is no evidence that non—occupational exposure to chromium constitutes a cancer hazard.” Treatment Methods for treatment of total and hexavalent chromium are pH adjustment followed by ferrous sulfate coagulation. The insoluble forms of chromium can be removed by conventional sedimentation and coagulation processes. Trivalent chromium can be removed by lime softening and coagulation with alum or iron. Chromium compounds are quite often found as corrosion control inhibitors in cooling waters and there is a possibility of contamination through cross—connections. In such cases of contamination, obviously correction of the cross—connection is the appropriate remedial action. Guidance It is recommended that exemptions for trivalent chromium up to 0.5 mg/i, and 0.1 for hexavalent chromium, may be given for short time periods necessary to provide adequate treatment (or alternate solutions) to reduce the chromium level to or below the 0.05 mg/i MCL. 5. Fluoride (1.14_2.14 mg/i dependent on temperature) Occurrence In 1969 the Community Water Supply Survey of the Public Health Service sampled 969 water supplies and found fluoride ranging from less than 0.2 up to 14.110 mg/liter. Fifty—two systems had fluoride concentrations greater than the then recommended limits for this constituent. A more extensive survey in the same year by the Dental Health Division of the Public Health Service (1970) showed that 8.1 million people in 2,630 communities in 114 states ------- 111—11 were consuming water with more than 0.7 mg/liter of naturally occurring fluoride. Nearly one million people in 521 communities were receiving water with more than 2 mg/liter of naturally occurring fluoride. Most of the communities with more than 0.7 mg/liter natural fluoride were in Arizona, Colorado, Illinois, Iowa, New Mexico, Ohio, Oklahoma, South Dakota and Texas. There were no reports of community water supplies with as much as 0.7 mg/liter fluoride from Delaware, Hawaii, Massachusetts, Pennsylvania, Tennessee or Vermont. Health Effects The physiological response to elevated fluoride levels is the occurrence of various degrees of fluorosis, or dental mottling, affecting teeth during their formative stages. Further manifestations of physiological harm can occur from ingestion of high levels of fluoride, but no water supplies in this country are known to have sufficiently high fluoride levels to cause other than dental mottling. At levels up to 8 mg/i (and possibly higher) there have been no other known harmful effects on adults drinking such water. The severity of mottling (affecting children only) and the number of children affected can be assumed to be in proportion to the extent the maximum contaminant level is exceeded. Sufficient variations from this proportion exist to warrant using some other means for determining that there is no unreasonable risk to health. The affected supply should obtain some epidemiological data to substantiate the claim of no adverse health risk. Treatment Conventional procedures of water treatment, i.e. clarification, filtration, softening, disinfection, have little or no effect on the fluoride concentration in water. However, it was noted in Ohio in the 1930’s that if the pH were increased during softening operations to a value high enough to precipitate magnesium hydroxide, some removal of fluoride was accomplished (Scott, et al., 1937). In most full—scale plants the removal of fluoride was less than 50 percent. Two processes have been used for fluoride removal, both based on the adsorption of fluoride on granular media, either activated alumina or bone char (Maier, 1963). The water containing fluoride is passed through a bed of the medium until the effluent concentration exceeds an acceptable value. The medium is then regenerated with a solution of sodium hydroxide to remove adsorbed fluoride. ------- 111—12 Guidance Exemptions should be based upon the risk to health from the occurrence of water—related moderate—to—severe fluoro— 313, (e.g., “Dean’s Community” index exceeding 1.5) and the availability of higher quality water via treatment or blend- ing with other sources. While additional studies are being conducted by EPA and the National Institute for Dental Research, exemptions should be readily available up to about four times the optimal, providing it can be shown that water—related excess moderate—to—severe fluorosis is not evident. In questionable cases or where higher fluoride concentrations are encountered, exemptions and compliance schedules should be determined by the State primarily from well—designed epidemiological studies involving children who have resided in the community of interest for an extended period of time. 6. Lead (0.05 mg/l) Occurrence A survey of the mineral content of finished water in the 100 largest cities in the United States was made in 1962 (Shapiro). For lead, the following values were found: maximum, 62 ug/liter; median, 3.7 ug/liter; minimum, not detectable. In another study of raw and finished water in the United States, covering the period 1962—1967, Knopp (1973) reported the following data for finished water: frequency of detection, 18.1%; minimum, 1 ug/liter (minimum detectable source); maximum, 139 ug/liter; mean, 33.9 ug/liter. The corresponding values for raw water were as follows: frequency of detection, 19.32%; minimum, 2 ug/liter; maximum, 1 0 ug/liter; mean, 23 ug/liter. The increment in the mean value for finished water suggests that lead was picked up from plumbing systems. Water samples collected at the tap serviced by 969 water systems throughout the United States indicated an average lead concentration of 13.1 ug/liter (Mccabe, 1970). Of the 2,595 samples, 1. 4% contained levels higher than the MCL of 50 ug/liter, with a maximum of 6’ ug/liter. Available data generally indicates that the addition of lead to drinking water occurs chiefly in the distribution system, including household plumbing, and this is most likely to occur with soft “aggressive” water. ------- 111—13 Important local variations occur, apparently in relation to the use of soft “aggressive” water of slightly acidic pH and the use of lead pipe in service and domestic water lines. Craun and McCabe (1975) have used data from Seattle and Boston to illustrate the effect of “corrosive” water of slightly acidic pH on lead concentrations in finished drink- ing water. Karalekas et. al., (1975) have made further studies in the metropolitan Boston area by collecting multi- ple water samples from 383 households in Boston, Cambridge, and Somerville, Massachusetts. These cities were selected for study mainly because of the wide use of lead pipe in service lines. Lead concentrations at the tap ranged from 13 to 1,150 ug/liter, with a mean of 30 ug/liter. In all cases, the lead content of drinking water was higher at the tap than at the treatment plant. Highest concentrations were found in early morning samples, with the lowest mean concentrations in running water and intermediate values in standing water and in composite samples obtained throughout the day. Very substantial reductions have been obtained by raising the pH of the water to approximately 8. Various lead salts are not highly soluble in water (the carbonate and hydroxide are insoluble and the sulfate is slightly soluble). Natural waters in limestone galena areas can have lead levels ranging from 0.14_0.8 mg/l, although fortunately, these areas are rare. Contamination usually occurs from industrial and mining effluents and from the use of lead and galvanized water piping. Health Effects If one uses the critical toxic effect approach to preventive medicine (Nordberg, 1976), then a water lead content of’ 100 ug/liter at the household tap is not acceptable. The NAS data suggested that the present limit of 50 ug/liter may not, in view of other sources of environmental exposure, provide a sufficient margin of safety, particularly for fetuses and young growing children. The physiological response to lead is both acute and chronic, and varies from gastrointestinal disturbances to encephalopathy, depending on total accumulation of lead in the body. Treatment Elevated lead levels from piping systems and aggressive water can be controlled by pH and alkalinity control and stabilization or pipe replacement. Where high concentration is due to contamination of natural waters, conventional treatment methods (settling, alum and ferric chloride coagulation, and lime softening) are extremely effective. ------- 111—1 14 Guidance Because of the very small margin of safety, and because lead levels can usually be readily controlled, no variances should be granted for lead in drinking water and exemptions only where no other course is possible. Steps must be taken immediately to achieve compliance and provide alternate drinking water for young children and pregnant women. 7. Mercury (0.002 mg/l) Occurrence The Department of Interior carried out a nationwide reconnaissance of mercury in U.S. water in the summer and fall of 1970 (Jenne et al., 1972). Of the samples from the industrial wastewater category, 30% contained mercury at greater than 10 ug/liter; nearly 0.5% of the samples in this group contained more than 1,000 ug/liter. Only 14% of the surface—water samples contained in excess of 10 ug/liter. The higher mercury concentrations were generally found in small streams. About half the 143 samples from the Mississippi River contained less than 0.1 ug/liter. The mercury content of lakes and reservoirs was between 0.1 and 1.8 ug/liter. With few exceptions, the mercury content of groundwater samples was below detection. In a survey done by the EPA Division of Water Hygiene, 273 community, recreational and Federal installation water supplies were examined. Of these 261 or 95.5% showed either no detectable mercury or less than 1.0 ug/liter in the raw and finished water. Eleven of the supplies had mercury concentrations of 1.0—14.8 ug/liter. The current problems concerning mercury contamination of the environment appear to be related mainly to rnethylmercury compounds. The presence of these compounds in foods (principally in fish) and the accidental ingestion of treated seed grain or the ingestion of meat from animals that had been fed grain treated with alkylmercury compounds are the major concern. Limitations are imposed or are being imposed by responsible agencies on the industrial discharge of mercury containing wastes that contribute to methylmer- cury contamination of fish, on the allowable mercury content in fish used for human consumption, and on the use of mercurial fungicides, and these actions should minimize the mercury hazard to man from these sources. ------- 111—15 Health Effects Exposure to metallic mercury via routes other than inhalation is infrequent. However, metallic mercury (or mercury salts) can be converted by bacterial action into organic mercury óompounds, notably methylmeroury. Methylmercury and other short—chain alkylmercury compounds exert their main toxicologic effects on the nervous system. The factors that determine the biotrans- formation of mercurials, their passage through barriers in the body, and the ultimate action on cellular mechanisms are only beginning to be understood. Chronic alkyl mercury poisoning, also known as Minimata Disease, is an insidious form of mercurialism whose onset may appear after only a few weeks of exposure or may not appear until after a few years of exposure. Poisoning is characterized mainly by major neurological symptoms and leads to permanent damage or death. The clinical features in children and adults include numbness and tingling of the extremities, incoordination, loss of vision and hearing, and intellectual deterioration. Autopsy of the clinical cases reveals severe brain damage throughout the cortex and cerebellum. There is evidence to suggest that compensatory mechanisms of the nervous system can delay recognition of the disease even when partial brain damage exists. From epidemiological evidence, the lowest whole—blood concentration of rnethylmercury associated with toxic symptoms is 0.2 ug/g. This value corresponds to prolonged, continuous exposure at approximately 0.3 mg Hg/70 kg/day. Applying a safety factor of 10 to this value results in an “acceptable daily intake” of 0.03 mg of mercury, or about 0. ug/kg of body weight. It should be noted that the major source of mercury in the diet is fish, and that the ADI can readily be attained by the consumption of a moderate quantity fish with the FDA—permitted concen- tration of mercury. Treatment Inorganic mercury can be removed by iron and alum coagulation, and lime softening is also moderately effective. Granular activated carbon and ion exchange show promise for inorganic mercury removal. Organic mercury, while more difficult to remove, can be treated with powdered or granular activated carbon. ------- 111—16 Guidance It is recommended that no variance be granted for mercury as conventional treatment methods are adequate to reach the MCL or below. Exemptions for inorganic mercury can be issued in order that appropriate treatment facilities can be placed into operation and the time schedule should be kept to a minimum. No exemptions should be issued for organic mercury contamination. 8. Nitrate (10 mg/i as N) Occurrence Major point sources of combined nitrogen are municipal and industrial wastewaters, refuse dumps, animal feed lots and septic tanks. Diffuse sources include runoff or leachate from manured or fertilized agricultural lands, urban drainage and biochemical nitrification. A few tenths of a milligram per liter of combined nitrogen occurs in rainfall from solution of atmospheric ammonia and oxides of nitrogen. In the Community Water Supply Survey of 1969, the range of nitrate concentrations found was 0.0—127 mg/liter. Nineteen systems, about 3% of those examined for nitrate, had concentrations in excess of the then recommended limit of 1 5 mg/i. Ground waters from shallow wells often have high concentrations of nitrate. Statewide records in Illinois show high nitrate to be more common in wells less than 50 feet deep (Larson and Henley, 1966). Analyses of over 5,000 waters in Missouri showed that 27 percent of the waters contained nitrate—nitrogen in excess of 10 mg/liter (Smith, 1970). Forty—five percent of 250 wells in Wisconsin that were examined twice monthly for more than a year, consistently yielded water containing more than 10 mg/liter nitrate—nitrogen and 71 percent of the well waters exceeded this level at least once. (Crabtree, 1970). In Nassau County, New York, 370 wells supply 1.5 million people. In 1969, water from twenty of these wells showed more than 10 mg/liter nitrate-nitrogen (Smith and Baier, 1969). In Southern California, certain public water supplies have exceeded 10 mg/liter nitrate—nitrogen since 1935. Health Effects Nitrate may be converted to nitrite. Nitrite is directly toxic by reaction with hemoglobin to form methemoglobin and causes methemoglobinemia. It also reacts ------- 111—17 readily under appropriate conditions with secondary amines and similar nitrogenous compounds to form N-nitroso compounds which are potent carcinogens. Epidemiological evidence on the occurrence of methemoglobinemia in infants tends to confirm a value near 10 mg/liter nitrate (as nitrogen) as a maximum contaminant level for water with no observed adverse health effects, but there is little margin of safety in this value. The occurrence data on methemoglobinemia show that incidence rate increases as nitrate concentration increases, but that below about 20 mg/liter nitrate as nitrogen the incidence rate remains low. Only one case of methemoglobinemia has been solely attributed to public water supplies. (APHA, 1950; NAS, 1977). The highly sporadic incidence of methemoglobinemia when drinking water contains greater concentrations of nitrate suggests that factors other than nitrate intake are important in connection with development of the disease. These factors include intestinal bacteria, dietary intake, bacterial contamination of the water, etc. Each link in the chain of reactions from nitrate to N— nitroso compound(s) has been shown to occur in some situa- tions in man or other animals. The extent of operation of the overall reaction chain in humans has not been shown, and the mechanism by which other environmental or internal factors affect potential formation of N—nitroso compounds is not known. Surveys indicate that water containing less than 10 mg/l nitrate—nitrogen has not caused methemoglobinemia, while serious and occasionally fatal poisonings in infants have occurred in some cases when water concentration exceeded 10 mg/i. In no case should waters with nitrate—nitrogen concentrations greater than 10 mg/l be used for feeding infants below 6 months of’ age. There is very little safety factor inherent in the 10 mg/l limit for infants. Where the limit is exceeded and while alternative sources are being sought or treatment facilities are being installed, extremely diligent efforts should be made to assure that the water is not used for infant feeding. It must be remembered that consumption of water with a high (greater than 10 mg/l) concentration of nitrate- nitrogen for a period as short as a day may result in the occurrence of methemoglobinemia. ------- 111—18 Treatment An ion exchange process specifically designed for nitrate removal has been developed. However, since the presence of nitrate in ground waters is frequently the result of contamination from the surface, protection of the water source by proper well construction or modification can often effectively eliminate nitrate from these waters. Guidance Exemptions may be granted up to 20 mg/i N0 3 —nitrogen so long as nitrite is not present at levels approaching 1 mg/l nitrite—nitrogen. Ip every case where an exemption from the MCL is granted the following actions should be taken immediately: 1. Public notice should be given through available media (newspapers, radio, television, etc.) that water from the public water system is not to be used in preparing infant formula until corrections have been made or the MCL is no longer exceeded. 2. Physicians should be notified utilizing the licensure register and requested to advise their patients with infant children (up to 6 months) of the potential problem. 3. Special efforts should be made to notify the transient population of the existing situation (e.g., through placarding). 1t. Conveniently placed, low nitrate water should be provided for the high risk population. 5. The local health department, visiting nurses association, and pediatrics departments of hospitals should be informed so they can take the necessary precautions and properly advise parents of infant children. 6. Notification given in 2. and 3. above should be repeated at 3—month intervals until the nitrate concentra- tions meet the MCL. Provision of bottled water having satisfactory nitrate content is also recommended for the high risk group during the exemption period. ------- 111—19 9. Selenium (0.01 mg/i) Occurrence An extensive study by the Department of Health, Education and Welfare involving analyses of 535 samples of water from major U.S. watersheds indicated that only two isolated samples contained selenium at more than 10 ug/liter of water (Lakin and Davidson, 1967). In another study, over a two year period, it was reported that there was a maximum of 10 and a mean of 8 ug/liter in the finished water of 19 4 public water supplies (Taylor, 1963). In a study in Oregon, the majority of farm samples of water had less than 1 ug/liter (Hadjimarkos and Bonhorst, 1961). River water may contain high concentrations of selenium where irrigation drainage from seleniferous soils empties into it. Values of 2,000 ug/liter have been reported (Williams and Byers, 1935). Waters from some springs and shallow wells contain selenium at more than 100 ug/liter (Eyers, 1938; Miller and Byers, 1935; Morette and Diven, 1965), but, deep wells may contain only a few micrograms per liter. Waters from some Wyoming wells contain enough selenium to be poisonous to man and livestock (Beath, 1962). In another report from Wyoming, a high concentration of selenate in well water on an Indian reservation was associated with the loss of hair and nails in children (Beath, 1962). Health Effects Available reports indicate little danger of toxicity from amounts of selenium found in finished waters, but wells drilled through seleniferous shale containing soluble selenium may have concentrations of selenium high enough to be of concern. The determination of a “suggested no—adverse reaction level” for selenium is complicated by numerous experimental variables. The toxic effect of selenium depends on the type of selenium compound encountered, whether it is organic or inorganic, the valence state of the selenium ion, the species and sex of the laboratory animal used, the age of the animal, the conditions and duration of the test, and the diet——whether natural or semipurified ingredients, the protein content, the caloric intake, the type of protein, and the presence and concentrations of other elements, such as arsenic, mercury, thallium, and fluorine. Total exposure is the significant factor; human exposure from food and air may be elevated in those areas with high natural selenium levels in the drinking water. ------- 111—20 The National Academy of Sciences (Committee on Nutritional Misinformation, 1976) reported 2 00—3OOO ug selenium as the daily dose for overt selenium intoxication in humans after long-term exposure. On applying a safety factor of 10 for sensitive populations, the acceptable daily intake dose has been calculated as 2k0—300 ug of selenium. Since, selenium exposure from the diet in areas with high natural selenium levels is approximately 200 ug/day or 200 ug daily, total exposure from drinking water should not exceed more than approximately 140 1OO ug selenium daily in those areas. Treatment The literature indicates that selenium is found as an anion in aqueous solutions as either Se0 3 2 (selenite) or SeO 2 (selenate). Laboratory experiments and pilot studies have shown that alum and ferric sulfates coagulation and iiq e softening are moderately effective for the removal of e ’ (selenite) from water. Although the studies on Se ° (selenate) are preliminary, they indicate that selenate can be removed by use of ion exchange and reverse osmosis. Guidance In granting variances and/or exemptions, it is important to know the valence form in order to determine the feasibil- ity and cost of removal. Assuming consumption of 2 liters of water daily per adult, exemptions for selenium in drinking water may be granted up to 20 ug — 50 ug per liter. 10. Silver (0.05 mg/i) Occurrence Silver should present no problem in water. It is not found as a natural constituent of drinking waters. The need for a standard arises from the intentional addition of the element to water as a disinfectant. Health Effects The limit of 50 ug/liter is based on the possible occurrence of argyria, a blue—gray discoloration of the skin, eyes and mucous membranes, resulting from the introduction of one gram of silver into the body. Assuming that all silver ingested is deposited in the skin, it is calculated that 50 ugh silver could be ingested for approximately 27 years before 1 gram of silver would be deposited. ------- 111—2 1 Guidance It is recommended that no variance or exemptions should be given. D. Organic Compounds Chiorophenoxys 2, 1 t—D 0.1 mg/i 2,k,5 TP Siivex 0.01 mg/i Chlorinated Hydrocarbons Endrin 0.0002 mg/i Lindane 0.O0 mg/i Methoxychior 0.1 mg/i Toxaphene 0.005 mg/i 1. 2, 1 4—D (0.1 mg/i) Occurrence 2, 1 1—D is found in water (Manigold and Schuize, 1969). Concentrations as high as 70 ppb have been detected in Oregon streams after aerial application to forest land (Hiatt, 1976). 2,4—D was detected in raw water at 0.05 ug/liter, in Lafayette, Indiana (USEPA, 1975j). The NAS has reported 2, 1 4—D up to O.0 ug/l in water (! 2 FR 132135776, 1977). Few surveys have found 2, —D in finished water; therefore, no average or median is reported. An ongoing organics survey may have these figures within the year. Health Effects The acute toxicity of 2,L _D in man includes fibriliary twitching and muscular paralysis. Serum glutamie oxalacetic transaininase, glutamic pyruvic transaininase, lactic de— hydrogenase, aldolase and creatine phosphate were increased, and both hemoglobinuria and myoglobinuria were observed. A 1—month loss of sexual potency was reported (Berwick, 1970). After a 23—year old man used 2, —D in suicide, the lethal dose was estimated to be over 90 mg/kg (Nielson, 1965). Assouly (1951) is reported to have taken 2, —D daily at 8 mg/kg for 3 weeks without harmful effects. Data from Dow Chemical Co. (Johnson, 1971) on 220 workers exposed to 2, 1 -D at O. 3—O.57 mg/kg per day over a period of 0.5—22 years showed no significant differences from data on an unexposed human population. ------- 111—22 The acute toxicity of 2,k—D is moderate in a number of animal species with LD 50 values of 100_5111 mg/kg for rats, mice, guinea pigs, chicks, and dogs (Drill and Hiratzka, 1953; Rowe and Hymas, 19514). Salts and esters of 2, 1 4—D show an even lower degree of acute toxicity. The subchronjc and chronic effects are outlined below: Young adult female rats were given oral doses of 2, 1 4-D in olive oil at 0, 3, 10, 30, 100 and 300 mg/kg five times a week for 14 weeks (Rowe and Hymas, 19514). No adverse effects were noted at 30 mg/kg and below but depressed growth rates, liver pathology, and gastrointestinal irritation occurred at 300 mg/kg. In another experiment (Rowe and Hymas, 19514), depressed growth, liver pathology, mortalities and increased liver/body weight ratios were observed in rats fed 1,000 ppm 2,k—D for 113 days. 2, 1 1—D was administered orally to dogs at dosage levels of 0, 2, 5, 10, and 20 mg/kg five days a week for 13 weeks (Drill and Hiratzka, 1953). Three of four animals receiving 20 mg/kg dose died within 149 days. These animals showed a definite decrease in the percentage of lympocytes in the peripheral blood. The surviving animals in all groups did not show any hematological abnormalities. Dietary levels of 0, 5, 25, 125, 625 and 1,250 ppm technical grade 2,4—D were fed to female and male Osborn—Mendel rats for two years (Hansen et al., 1971). No significant effects were observed on growth, survival rate, organ weights, or hematologic parameters. There was also no elevated incidence of tumors over that seen in controls. In a parallel study (Hansen et al., 1971), groups of 6—8 month old beagle dogs received 0, i 7 50, 100 and 500 ppm of technical 2,14—D for 2 years. No 2, 1 4—D related effects were noted. None of the lesions observed in the 30 dogs were believed related to the treatment. The no—adverse effect level of 2, 1 4—D in the dog has been established at 8.0 mg/kg/day (Lehman, 1965). Studies on 2,k—D showed that there was no significant increase in the incidence of tumors in various mouse strains initially given 2, 1 4—D or its esters at 146.14 mg/kg/day orally on days 7—28 post—natally to dams followed by dietary feeding up to 323 ppm for 18 months (USEPA, 197 1 4b). In another study, mice that received 2,14—D orally for their life span showed no increased incidence of tumor formation. (Vettorazzi, 1975b). ------- 111—23 A study (Arkhipor and Kozlova, 197k) reported that two rats developed fibroadenoma and one hemangioma 27-3 1 months after receiving one—tenth the LD 50 of the amine salt orally. Subacute injections in mice produced no tumors after 33 months. In a three—generation, six—litter, Osborne—Mendel rat reproduction study, no deleterious effects due to technical 2, 1 4—D at dietary doses of 100 or 500 ppm were observed (Hansen et al., 1971). At 1,500 ppm, however, 2, 1 —D, although affecting neither fertility of either sex nor lit- ter size, sharply reduced the percentage of pups and the weights of the weanlings that survived to weaning. Bage et al. (1973) observed teratogenic and embryotoxic effects in NMRI mice that received 50 or 110 mg/kg injections of 2, 1 4—D on days 6—1 4 of gestation. Pregnant rats were treated orally with 2,k—D at 12.5, 25, 50, 75, and 87.5 mg/kg/day (maximal tolerated dose) or equimolar doses of propylene glycol butyl ether ester of 2, 1 —D up to 1 2 mg/kg/day or isooctyl ester of 2,4—D up to 131 mg/kg/day on days 6—15 of gestation (Schwetz et al. 1971). Fetotoxic responses were seen at high dosages, but teratogenic effects were not seen at any dosage tested. The authors suggested that the no—adverse effect dosage of 2, 1 4-D (or the molar equivalent, in the case of the esters) was 25 mg/kg/day. Prenatal studies on 2, 1 4—D in Wistar rats showed that it induced fetotoxic effects and an increased incidence of skeletal anomalies after single oral doses of 100—150 mg/kg/day on days 6-15 of gestation (Khera and McKinley, 1972). At the highest dosage of 150 mg/kg/day, the isooctyl ester, and butyl ester, and butoxyethanol and dimethylamine salts of 2,k—D were all associated with significantly increased teratologic incidence. The butyl and isooctyl esters also tended to decrease fetal weight. At a lower dosage, 2,4—D and its salts and esters induced no apparent harmful effects. Pregnant hamsters received technical 2,k—D (three samples) at 20, 0, 60, and 100 mg/kg/day orally on days 6—10 of gestation (Collins and Williams, 1971). Fetal anomalies were produced occasionally with 2, 4—D, and the fetal viability per liter decreased; but neither effect was clearly dose—related. The lowest dose causing fetal anomalies with the three technical 2, 1 —D samples was 60 mg/kg/day. ------- III 21 The NAS concluded that the acute toxicity of 2, 1 1—D is moderate. No adverse effect doses for 2, 1 —D were up to 62.5 mg/kg/day and 10 mg/kg/day in rats and dogs respectively. Based on these data, the NAS derived an ADI which was calculated at 0.0125 mg/kg/day. The available data on subchronic and chronic toxicity and calculations of ADI are summarized in Table 111—1. There are substantial disagreements among various investigators concerning the results of subchronic and chronic toxicity studies with 2,4—D, perhaps reflecting the use of different formulations or preparations. Treatment Activated carbon was effective in reducing 2, 4—D to below the MCL (Whitehouse, 1967) (Whitehouse, J. D., A Study of the Removal of Pesticides from Water, University of Kentucky, Water Resources Institute, Research Report No. 8, Lexington, Kentucky, 1967). Guidance The present drinking water MCL (0.1 mg/i) for 2,k—D is in agreement with the above recommendations of the NAS. Computation of an acceptable level for 2, 1 4—D in drinking water from the NAS recommendations would result in 0.125 mg/i 2, 1 4—D in drinking water, if one assumes 10 kg body weight for an average child consuming I liter per day for chronic exposure. Therefore, the present drinking water MCL for 2, 1 —D, 0.1 mg/i, is below the level as calculated above from the NAS recommendations and provides an extra margin of safety. Exemptions up to 0.2 mg/i may be granted. The sources of the contaminants should be controlled. 2. 2, 1 ,5—TP (0.01 mg/i) Health Effects The acute toxicity of 2, 4,5—TP in animal species other than man is summarized below: The oral LD 50 of 2,4,5—TP is reported to be 650 mg/kg and 500 mg/kg in rats (Toxic Substances List, 197k: Rowe and Hymas, 195k) and 850 mg/kg in guinea pigs. In rats and rabbits, the oral LD 50 of the mixed butyl esters and propylene glycol esters ranged between 500 and 1,000 mg/kg (Rowe and Hymas, 195k). ------- 111—25 The oral LD 50 of 2,4,5—TP is 1410 mg/kg in rats, and 560 mg/kg in mice (Toxic Substances List, 1974: Vershuren et al., 1975), 550 mg/kg in female guinea pigs, 813 mg/kg in female rabbits and 940 mg/kg in female chickens. LD 50 values in the rat and mouse by intraperitoneal administra- tion are 1400 and 500 mg/kg, respectively. The subchronjc and chronic effects are summarized below: The propylene glycol butyl ether ester of Silvex (Kuron) was fed to male and female rats in the diet at 10, 30, 100, 300, and 600 mg/kg/day for 90 days (Mullison, 1966; USEPA, 1975k). Mortalities were observed at 600 mg/kg/day, growth decrease at 300 and 600 mg/kg/day, and increased liver weight at 30 mg/kg/day and above. No toxic effect was found in animals receiving 10 mg/kg/day. In another 90—day study (Mullison, 1966; USEPA, 1975k), male and female rats received the sodium salt of 2, 4,5—TP in the diet at 100, 300, 1,000, 3,000, and 10,000 ppm. Growth was decreased at 300 ppm (277 ppm 2,14,5—TP equivalent) and above, and liver weight was increased at 100 ppm (2, 1 4,5—TP equivalent, 92 ppm). Histopathologic examination showed liver and kidney damage at all dietary concentrations, except that the kidneys of females were not affected at 100 ppm. Beagles were fed Kurosol SI (a formulation containing the potassium salt of 2,4,5—TP at 60%, or the equivalent of 2,4—TP at 53%) of 100, 300, and 1,000 ppm for 89 days (Mullison, 1966; USEPA, 1975k). No adverse effects were noted at 100 ppm or 300 ppm (2,4,5—TP equivalents 53 or 160 ppm), but a growth rate decrease occurred at 1,000 ppm in females. Male and female rats were fed Kurosol SI at 10, 30, 100 and 300 ppm for 2 years (Mullison, 1966; USEPA, 1975k). Increased kidney weight was seen in males that received 300 ppm, but there were no-adverse effects at 10, 30, and 100 ppm. The no—adverse effect concentration was considered to be 100 ppm (2,14,5—TP equivalent, 53 ppm) (Mullison, 1966). The same formulation was fed to beagles at 56, 190 and 560 ppm for 2 years (Mullison, 1966; USEPA, 1975k). Dogs fed 560 ppm showed severe liver pathology after 1 year. At 190 ppm, liver pathology was seen in females sacrificed after 1 year, but not in animals sacrificed at 2 years; in males, no liver pathology was seen at 1 year, but it was present at 2 years. The no—adverse effect content thus was 56 ppm (2,14,5—TP equivalent, 30 ppm) for males and 190 ppm ------- 111—26 (2,k,5—TP equivalent, 101 ppm) for females (Mullison, 1966). Another report cited 5 mg/kg/day as the no—adverse-effect dosage for 2, 1 ,5—TP in rats and dogs in 2—year feeding studies (Johnson, 1971). The potential for carcinogenicity was tested in young male and female mice of the (C57BL/6 x C3H/Anf)F and the (C5TBL/6 x AKR)F strains. The mice received 2, ,5—TP orally at mg/kg/day on days 7—28 and thereafter were placed on a diet containing 2, ,5—TP at 121 ppm for approximately 18 months (Innes et al., 1969). There was no increase in the incidence of tumors above control values for either strain. Rats were tested for teratogenicity and overt toxicity, at doses of 35 mg/kg or below (USEPA, 1975k). No adverse effects were observed. In the two year feeding studies the no—adverse-effect doses for 2, 1 ,5—TP were 5 mg/kg/day and 6.8 mg/kg/day in dogs and rats respectively. Based on these data the NAS (Drinking Water. and Health) calculated the ADI to be 0.00075 mg/kg/day for 2, 1 4,5—TP. The accompanying Table No. 111—2 summarizes the studies used and the calculations to deter- mine the ADI, and the suggested no—adverse reaction levels. Chlorinated dioxins may be contaminants of 2, 1 4,5—TP. Treatment Activated carbon was effective in reducing 2, ,5—TP to below the MCL (Whitehouse, 1967) (Whitehouse, J. D., A Study of the Removal of Pesticides from Water, University of Kentucky, Water Resources Institute, Research Report No. 8, Lexington, Kentucky, 1967). Guidance The present drinking water MCL, 0.01 mg/l, for 2, ,5—TP is in agreement with the above recommendations of the NAS. Computation of an acceptable level for 2, 1 4,5—TP in drinking water from the NAS recommendations would result in 0.0075 mg/i 2, I,5—TP in drinking water, if one assumes 10 kg weight for an average child consuming 1 liter per day. Exemptions up to 0.02 mg/i may be permitted until compliance can be achieved. The sources of contamination should be controlled. ------- 111—27 3. Toxaphene (0.005 mg/i) Occurrence Toxaphene has been detected but not quantified at least once in finished water. Although there are some case reports of acute Toxaphene poisoning, poisoning in humans is rare. When Toxaphene was first used, four cases of poisoning by ingestion in children under 11 year olds were reported (McGee et al., 1952). The same study contained a description of severe Toxaphene poisoning in adults after its misuse in agriculture. The authors estimated that three patients ingested Toxphene at 9.5 - 117 mg/kg. Health Effects Aside from accidental poisoning, human volunteers have participated in Toxaphene toxicity studies. In one study, 50 human volunteers inhaled mist containing Toxaphene at 0.0011 mg/liter for 10 mm/day for 15 days; there were no observed adverse effects (USEPA, 197 11 c). In another study, a mist containing Toxaphene at 0.25 mg/liter of air was inhaled by 25 people for 30 mm/day for 13 days; there was no evidence of local or systemic toxicity (USEPA, 197 11 c). Acute toxicity studies with Toxaphene have involved oral, dermal, intravenous, intraocular, and inhalation exposure. The toxicity of Toxaphene is influenced by the solvent or vehicle used. When administered orally as a solution or emulsion, it is more toxic in a digestable vegetable oil than in an oil like kerosene. Toxicity of Toxaphene by skin absorption is much less from an inert dust than from an oily solution. The acute oral LD 50 is 90 mg/kg in male rats and 80 mg/kg in female rats; the acute dermal LD 0 is 1,075 mg/kg in male rats and 780 mg/kg in female ra€s (Gaines, 1960). Administration of a 20% solution of Toxaphene in kerosene to the eyes of rabbits and guinea pigs for 111 consecutive days produced mild irritation of the eyelids with loss of hair around the eyelids. The eyes were not injured, and the irritation in the eyelid was abated within 10 days (USEPA, 1974c). In acute inhalation studies, 110% Toxaphene dust at 3.11 g/liter of air killed approximately half the exposed rats within 1 hour. Ortega et al., (1951) have studied the subchronic tox- icity of To p ne in small groups of rats fed 50 and 200 ppm in the diet for 9 months. No clinical signs of tox- icity, inhibition of food consumption, or growth rate were evident. However, only the liver, spleen, and kidneys were ------- 111—28 examined histologically. There was no apparent damage to the kidneys or spleen, but 3 of the 12 rats that received 50 ppm showed slight liver changes, and 6 of the 12 rats fed 200 ppm showed distinct liver changes. Degenerative changes in the kidney tubules and liver parenchyma have been reported in dogs fed Toxaphene at low dosages (Lacky, 19kg); two dogs received a k mg/kg/day (ab- out 160 ppm) for kk days, and two others received the same dosage for 106 days. Chronic studies have been done in rats, guinea pigs, dogs, cattle, sheep, and rabbits, In rats fed at 25, 100, and kOO ppm in the diet for the conventional 2-year period, only the liver showed significant changes, at 100 and kOO ppm (Fitzhugh and Nelson, 1951). Toxaphene was administered daily to dogs in a dry diet for 2 years. When it was fed at kO ppm, there was slight degeneration of the liver; at 200 ppm, there was moderate degeneration of the liver (USEPA, 197kc). Studies have also shown that, when Toxaphene is applied to the skin of many large animals (including cattle, sheep, goats, horses, and swine), adult animals can withstand high- er dosages than immature animals. Also, application of cot- ton patches treated with Toxaphene to the skin of 200 human subjects caused no primary irritation or sensitization. A three—generation reproductive study was conducted, ac- cording to currently accepted protocol for rats, with Tox— aphene at 20 and 100 ppm (Kennedy et al., 1973). No dif- ferences between control and Toxaphene—treated animals were reported, with respect to reproduction, performance, fertil- ity, lactation, or viability, size, and anatomic structure of progeny. In mutagenicity studies, occurrence of mutagenic effects among the controls and the animals treated with Toxaphene were similar. No evidence of carcinogenic action was reported in any of the chronic—toxicity studies previously undertaken. An ADI at 0.00125 mg/kg/day was calculated by the NAS on the basis of the chronic toxicity data. The available toxicity data and calculations of the ADI by the NAS are summarized in Tajle 111—3. Treatment Activated carbon is 99% (plus) efficient in reducing concentrations of the chlorinated hydrocarbon pesticides. When maximum concentrations of the contaminant in raw water ------- 111—29 do not exceed 20 ugh for endrin; 1400 ugh for lindane; 10,000 ugh for methoxychior; or 500 ugh for Toxaphene, carbon treatment will reduce the concentration to the MCL. Guidance It is assumed that the 10 kg child consuming one liter of water per day is the individual most sensitive to Toxaphene toxicity. Therefore, an MCL of 0.005 mg/i is equivalent to an exposure of 0.0005 mg/kg body weight. The MCL then provides a 2.5 safety factor when compared to the recommended ADI suggested by the NAS (0.00125 mg/kg). Exemptions up to the ADI (0.0125 mg/i) may be granted. I4 Methoxychior (0.1 mg/i) Occurrence No residues of methoxychior were detected in 500 samples of finished drinking water from the Mississippi and Missouri Rivers (Schafer et al., 1969) or in 101 samples from Hawaii. This compound has yet to be detected in drinking water. Health Effects The oral LD 50 In rats is over 6,200 mg/kg; that in mice is 2,900 mg/kg; that in monkeys is over 2,500 mg/kg. The dermal LD 50 in rabbits is over 2,800 mg/kg (USEPA, 1976e). The acute oral LD 5 ° of 2,2—bis—(p—hydrophenyl)— 1,1,1—trichloroethylene, the principal metabolite, In mice is 600 mg/kg (Von Oettingen and Sharpless, 19146). Methoxychlor chronically fed to rats at 10,000 ppm was toxic, but fed at 5,000 ppm for 52 weeks produced mortality comparable with that in untreated controls. There was some growth retardation at 2,500 ppm and above, but no gross pathologic changes were found. No tremors were observed at any time (Haag et al., 1950). Methoxychior fed to rats for 2 years at 0.02 produced no abnormal gross pathology or histopathologic changes (Haag etal., 1950). When fed to beagle dogs at 1, 2, and 14 mg/kg/day over 6 months, meth— oxychlor produced convulsions at the 2 and 14 g/kg level and increased serum alkaline phosphatase and serum transaminase (Tegaris et al., 1966). However, when fed at 300 mg/kg/day for 1 yeai7 T i another study, it had no observed effects on body weight, hematology, or histapathology (USEPA, 1976e). The carcinogenicity potential of methoxychlor was determined by the FDA. Methoxychlor fed in FDA studies for 2 years to C 3 He/FeJ and BALB/cJ mice at 750 ppm in the ------- I I I-. 30 diet showed no significant difference in incidence of hepatocellular hyperplasia and hepatoma between controls and treated mice. Testicular tumors were found in BALB/cJ mice, and it was concluded from an histologic examination that methoxychior caused a significant increase in the incidence of this tumor in BALB/cJ mice, but not in C 3 He/FeJ mice (USEPA, 1976e). Rats fed methoxychior at 1,000 ppm in the diet had normal reproduction. At 2,500 ppm, fewer rats mated, and many did not produce litters. At 5,000 ppm, none of the rats had litters or implantation (Harris et al., 19714). Further studies with 200 ppm through three generations showed no gross or histopathologic changes in any tissues from rats of the F 3 generation. Because of the possible resemblance of methoxychlor detoxication phenols (2,2—bis—(p—hydroxyophenol)—1,1,1— trichlorothane) to diethylstilbestrol, additional studies were made to evaluate chronic feeding of methoxychior for estrogenic effects. The results showed both no—adverse ef- fect and uterine weight increase. The latter effect was found to be at least partially due to an unidentified con- taminant in technical methoxychlor (Tuliner, 1961). Methoxychlor, a close relative of DDT, has very low mam- malian chronic toxicity. In a 2—year feeding study no adverse effect was observed at 200 ppm in rats. On the basis of these chronic data an ADI was calculated at 0.1 mg/kg/day. The available data on chronic toxicity and calculations of ADI are summarized in Table III— 4. Treatment Activated carbon is 99% (plus) efficient in reducing concentrations of the chlorinated hydrocarbon pesticides. When maximum concentrations of the contaminant in raw water do not exceed 20 ugh for endrin; 1400 ug/l for lindane; 10,000 ugh for methoxychior; or 500 ugh for Toxaphene, carbon treatment will reduce the concentration to the MCL. Guidance The present drinking water MCL, 0.100 mg/i, for methoxychior is in agreement with the above recommendations of the NAS and affords a safety factor of ten. The average daily intake of methoxychior in the human diet was less than 0.001 mg over a given period. Therefore, the present MCL is adequately protective of’ human health. The levels should not exceed the present MCL of 0.100 mg/l. ------- 111—31 5. Endrin (0.0002 mg/i) Occurrence Little is certain about the degradation and fate of en— drin; however, traces of it and its stable epoxide oxidation products are ubiquitous in the environment and are heavily bioconcentrated in the lipids of terrestrial and aquatic wildlife, humans, and foods, especially animal fats and milk. Less than 1 million pounds of endrin was produced in 1971. Because of the persistence of endrin and its degradation products, they are found in virtually every surface water (Drinking Water and Health, 1977). In an extensive (1958—1965) survey of the rivers of the United States, Briedenbach et al., (1967) found the average concentration of endrin to be 0.008—0.21k ppb. The highest concentrations were generally found in the lower Mississippi basin. In 196k, k6% were positive for endrin. More than 30% of finished water samples contained endrin (Schaefer, et al., 1969). It was concluded by Richard, et al., (197k) that water treatment plants were not removing substantial amounts of pesticides from raw water. The New Orleans water supply contained 0.00k ppb of endrin (USEPA, 1975j). Endrin was also identified in some other U.S. finished water supplies at concentrations of up to 80 ppt. Endrin is present everywhere in the environment, and is readily biomagnified through food chains, and is a common trace contaminant of human food. Market Basket Surveys of the U.S. diet, collected in five major U.S. cities and designed to simulate the diet of a 16—19—year—old male, showed that, on the average, 0.001 mg/day was consumed. The effects of endrin on animal and human health are very subtle and complex. Endrin is one of the most hazardous of all pesticides, because of its persistence, fat storage, and central nervous system target site. Health Effects Human illness and death have been observed after poisoning during the manufacture, spraying, or accidental ingestion of endrin. Typical symptoms of poisoning result from stimulation of the central nervous system and include headache, blurred vision, dizziness, slight involuntary ------- 111—32 muscular movements, sweating, insomnia, bad dreams, nausea, and general malaise. More severe illness is characterized by jerking of muscles or groups of muscles and epileptiform convulsions, with loss of consciousness, involuntary incontinence of urine and feces, disorientation, personality changes, psychic disturbances, and loss of memory. Such seizures may recur for 2 — 14 months after cessation of exposure and are marked by abnormal encephalographic patterns. These symptoms of severe poisoning have developed in 10 — 20% of spraymen working in WHO house-spraying programs (Hayes, 1957, 1959). Epidemics of’ endrin poisoning have occurred after the eating of bread made from flour accidentally contaminated with endrin; there were 59 illnesses in one episode (Davies and Lewis, 1956) and 8714, with 26 deaths, in Saudi Arabia (Weeks, 1967). At least 97 cases of fatal endrin poisoning were recorded through 1965 (USEPA, 1973a). It appears that ingestion of endrin at 0.2-0.25 mg/kg can produce convul- sions in humans (Hayes, 1963). Oral LD 50 in male and female rats are 17.8 and 7.5 mg/kg respectively, but the dermal toxicity (15 mg/kg) is roughly equivalent to the oral toxicity. Endrin fed to rats at 1 and 5 ppm in the diet produced no obvious effects over the life span, except for liver enlargement at 5 ppm. When it was fed at 25 ppm, the life span was shortened, and diffuse degeneration was seen in brain, liver, kidneys, and adrenals. Mice fed endrin at 0.1—14.0 ppm over their life span showed increased liver weights at 2 and 14 ppm and produced liver vascular damage. Convulsions were observed in dogs fed 2 and 14 ppm, and autopsies revealed pathologic changes in the brain (USEPA, 1973a). Endrin at very low dosages affects the central nervous system, producing encephalographic changes and altering behavior. Endrin was fed to rats at 2, 6, or 12 ppm in the diet for 2 years without producing primary malignant hepatic tumors or increasing tumor incidence in any organs (Dieckmann et al., 1970). Endrin has been subjected to the vigorous bioassay program of the NCI and found negative. However, the NAS has labelled endrin a suspect carcinogen (Drinking Water and Health). ------- 111—33 Treatment Activated carbon is 99% (plus) efficient in reducing concentrations of the chlorinated hydrocarbon pesticides. When maximum concentrations of the contaminant in raw water do not exceed 20 ugh for endrin; 400 ugh for lindane; 10,000 ugh for methoxychior; or 500 ugh for Toxaphene, carbon treatment will reduce the concentration to the MCL. Guidance Endrin in drinking water using the MCL of 0.0002 mg/i is less than 1/50 of the average daily consumption from food; therefore, the contribution of water to the total body burden is trivial. In the case of newborns (0 to 1 months), neonates (1 month to 6 months) and babies, 80—100% of’ the total daily intake may be in the form of baby formula. It has been demonstrated that endrin has great bioaccumuiation potential. It is for the above reasons that a conservative value has been chosen. Therefore, exemptions up to 0.00014 mg/i may be granted for only minimal times. Steps to eliminate endrin from the water must be initiated as soon as possible. 6. Lindane (0.0014 mg/liter) Occurrence The relatively high water solubility and vapor pressure of’ lindane cause it to have relatively low persistence in the environment. Lindane has been detected in the finished water ranging from non-detectable to 0.319 mg/i. On the average lindane is not detected. Only five reportable incidences have been above .0014 mg/i. In the verage daily diet of’ the 16—19—year—old male, 12.22 X 1O mg/day was present. In cows’ milk 0.02 ppm of lindane was present. Health Effects Over 30 cases of human exposure to BHC or lindane and 21 cases of exposure to BHC followed by the development of aplastic anemia have been reported in the literature (Loge, 1965; West, 1967; Woodliff et al., 1966). No satisfactory animal model simulating thatconditiOfl has been found and, despite efforts to study the question, a firm causal relationship between lindane or technical BHC exposure and aplastic anemia cannot be confirmed. Development of leukemia after lindane exposure was reported for two cases (Jedlicka, 1958). That casual relationship is also inconclusive in relation to insecticide exposure. ------- 111—311 Lindane is the most toxic of the isomers of BHC. It ex- cites the central nervous system, producing hyperirrita— bility, incoordination, convulsions, and death due to respiratory collapse. Its single—dose oral LD 50 in rats is 88—300 mg/kg (Gaines, 1969; Riemschneider, 19119; Burkatskaya, 1959; Slade, 19115; Kiosa, 1950; Woodward and Hogan, 19117; Copper et al., 1951). The oral LD 50 of technical BHC is 6ooT, 5o mg/kg; those of the other isomers are about 1,500 mg/kg (a) 2,000 mg/kg (8), and 100 mg/kg (6) (Reimschneider, 19119; Burkatskaya, 1969; Slade, 19115; Kiosa, 1950; Coper, 1951). The wide range in the observed LD 50 for lindane presumably results from differences in rates of absorption of various preparations of’ the material and variations in rates of detoxification and excretion under different experimental conditions. Single oral doses of 10—25 mg/kg in corn oil were fatal to beagles (Cited in USEPA, 1973b), and domestic animals were poisoned by similar amounts (Wasserman etal., 1960). Kliinmer (1955) administered daily doses of lindane, at 32 mg/kg of body weight, by stomach tube to male and female rats for 6 months. He observed nervous symptoms, fatty degeneration of the liver and renal tubular epithelium, vacuolization of the cerebral cells, and a marked increase in mortality. None of these effects was seen with a daily dose of 10 mg/kg during 17 months. Melis (1955) fed diets containing Lindane at 2, 3, 11, 5, or 10 ppm for 12 months to rats and found no abnormalities in general behavior, body weight, histology, or other characteristics. Beagle dogs were not affected by lindane in the diet at 7.5 mg/kg/day (Cited in USEPA, 1973b). Higher dosages produced central nervous system effects. Under conditions of chronic administration, the y—isomer is considerably less toxic than the other principal isomers or technical BHC. Fitzhugh et al. (1950) conducted 2—year- rat feeding studies with the various isomers of BHC, using diets containing the a, , and y—isomers. These experiments clearly showed that the y—isomer was the least toxic, and the 8—isomer, the most toxic. The organs injured were the liver and, to a lesser extent, the kidneys. In the case of lindane, the lowest concentration causing significant liver changes was 100 ppm; no effect was noted below 50 ppm. Truhaut (19511) summarized data from 2—year feeding studies in rats with lindane in the diet at 25, 50, and 100 ppm. At 25 ppm, no evidence of’ histologic changes in the liver or kidney or any other toxic effects were seen. At the higher concentrations, hypertrophy of the liver was observed, and, ------- 111—35 at 100 ppm, a slight degree of fatty degeneration. These findings and dose relationships were confirmed by other workers (Ortega et al., 1957). FAO/WHO (1967) accepted 25 ppm in the diet of rats as the maximal concentration causing no adverse effects. The hypertrophic liver and fatty degenerative changes of liver at higher dosage are similar to those produced by other slowly metabolized organochlorine compounds. As might be expected, lindane induces hepatic microsomal enzymes (Freal and Chadwick, 1973). That effect may precede in time and dosage relationship the liver pathology already described (Hotterer and Schaffner, 1968). The data on induction of liver tumors by y—BHC in mice are seen to be somewhat contradictory. For example, Thorpe and Walker (1973) found y’—BHC to be somewhat tumorigenic in CF1 mice but the Japanese workers used other strains and found that they were not susceptible to tumorigenic action (Nagasaki et al., 1971, 1972a, 1972b). The acute toxicity of technical BHC and BHC isomers also differs greatly among various mouse strains; the CF1 strain is particularly susceptible to acute poisoning (Miura et al., 1971t). Such toxicity differences may be related to different rates of’ metabolism of’ BHC; if’ so, the tumorigenic effects may also be related. The relevant carcinogenicity studies are summarized in Table 111—5. The chronic toxicity of the BHC isomers is clearly related to the tumorigenic effects so far observed only in rodents. The y isomer is the most strongly implicated; its activity is sufficient to account for the degree of hepatoma formation observed with technical BHC administration in mice. Lindane is a weaker tumorigen in mice, and is so far a questionable tumorigen in the rat. Treatment Activated carbon is 99% (plus) efficient in reducing concentrations of the chlorinated hydrocarbon pesticides. When maximum concentrations of the contaminant in raw water do not exceed 20 ugh for endrin; 1400 ugh for lindane; 10,000 ugh for methoxychior; or 500 ug/l for Toxaphene, carbon treatment will reduce the concentration to the MCL. Guidance As of’ 1972, the FAQ/WHO ADI for lindane was set at 0.0125 mg/kg/day. Later, that value was reduced to 0.001 ------- 111—36 mg/kg/day and held under temporary status because of the newer data concerning carcinogenicity. The FAO/WHO ADI for total exposure is based only on chronic toxicity. There- fore, the 0.0011 mg/i standard should not be exceeded for any substantial period. 5. Radionuclides The annual whole—body radiation dose in the United States averages about 180 mrem/year (1). Environmental sources average some 106 mrem/year via natural (102 mrem/year), fallout (11 mrem/year) and nuclear power (0.003 mrem/year). Medical exposures result in some 73 mrem/year, 72 mrem/year from diagnostic exposures and 1 mrem/year from radiopharmaceutjcals. Some 2.8 mrem/year results from miscellaneous sources including those encountered in the workplace. The radiation dose to any individual may vary substantially and is obviously related to his use of medical services and where he lives. The natural radiation dose varies markedly according to geological characteristics and altitude whereby an individual in Colorado may well receive an additional 100 mrem more than a person in Louisiana (2). The relative contribution that radioactivity in drinking water makes to ones overall radiation dose is small under normal conditions. Nevertheless, it appears that the radiation dose to the bone via a hypothetical water supply in the U.S. is approxpnately 11 mrem/year, the m jority of which comes from Ra 22 ° and the daughters of Ra 22 ° (2). 1. Combined Ra—226 and Ra—228 (5 pCi/l) Occurrence Radium—226 and Radium—228 are two naturally occurring radionuclides from the uranium and thorium series. Radium normally is found in groundwater of deep wells as opposed to surface water. In the Midwest, primarily Iowa, Illinois, Wisconsin and Missouri, the mean concentration of Ra—226 alone has been estimated to be approximately 5 pCi/i and the Safe Drinking Water Committee of the National Academy of Sciences suggests that in the entire U.S., over a million people consume water that contains more than 3 pCi/i of Ra—226 alone (2). Radium seldom occurs in surface waters unless influenced by mining or other industrial operations. Health Effects Radium—226 and Radium—228, like other radionuclides, are non—threshold carcinogens and pose a delayed threat to human health usually from chronic ingestion. The risk of bone and other cancers are linearly related to dose, and as a result, ------- 111—37 will increase as the radium concentration increases in the drinking water supply and in the body. Radium locates primarily in the bone where 80—85% of the retained radium is deposited. Other organs are also irradiated to a lesser extent, however. The aggregate health risk from radium ingestion estimated on the basis of lifetime exposure has been estimated by summing the dose and resultant risk from all organs. Risk estimates derived from the BEIR Report (1) indicate that the incremental risk from continuous consump- tion of drinking water containing Ra—226 and Ra-228 at the MCL of 5 pCi/i may cause an additional 0.7—3 cancers per year per million people exposed over their lifetimes. Almost all of these cancers would be fatal. The risk of drinking water containing greater concentrations of radium, resulting in higher radiation doses, would increase proportionally the number of fatal cancers. Treatment Treatment techniques to remove radium are available (3, li). Radium—226 has been demonstrated to be removed by precipitative lime softening, ion exchange softening and reverse osmosis with removal rates of 85%, 95% and 95%, respectively. Using conventional technology, raw waters having radium concentrations ranging from 5—100 pCi/i can be used for drinking water and can meet the 5 pCi/l limitation. Guidance The upper limit of the Federal Radiation Council (FRC) Range II guide for transient rates of radiuin—226 ingestion from both food and water is 20 pCi per day. Above this range, evaluation and application of additional control measures is always necessary (26 FR 9057, 1961). Provided that a comparable intake of radium via the food pathway is unlikely, exemptions for water supplies containing less than 10 pCi/i would be compatible with FRC guides. Occasionally, exemptions for concentrations exceeding 10 pCi/i, for strictly limited times, may be acceptable. In granting exemptions and establishing schedules for compliance, the primacy agency should consider the extent to which the MCL for radium—22 6 and radium—22 8 is exceeded, the number of persons at risk, the daily intake of radium from sources other than drinking water and the duration of time before compliance is likely to be achieved. Since treatment methods are readily available, compliance schedules should provide for early installation of treatment processes or for the use of alternative water supplies. ------- 111—38 2. Gross Alpha Particle Activity (15 pCi/i including Ra—226 but excluding U and radon) Occurrence Finished drinking water contains such alpha particle emitters as Ra—226, the daughters of Ra—228, Po—210, U, Th, Rn—220 and Rn—222. The occurrence of Ra—226 is becoming well documented. Special surveillance programs are identi- fying the abundance of uranium and radon in water. The occurrence of thorium mineral deposits and of Ra—228 and its alpha emitting daughters needs further defining. Health Effects The degree of risk from ingestion of an alpha particle emitting radionuclide depends on its specific chemical and physical properties. Rather than require extensive radio— chemical identification and measurement of all naturally— occurring and man—made alpha emitters, the current Interim Regulations require only the identification of radium—226 and are based on the conservative assumption that all of the alpha—emitting activity is due to long half—life radionu— clides. In many cases, the ingestion of 30 pCi/i of alpha emitting contaminants, other than radium—226, will result in substantially smaller doses to bone and other organs than would occur from the ingestion of radium—226 at 10 pCi/l. The dose equivalent to bone due to the chronic ingestion of 10 pCi/l of radium—226 is about 300 mrem* per year. Where analyses have identified the radioactive species, other than radium-226, contributing to the gross alpha concentration in drinking water, the 50—year dose to bone due to ingestion can be calculated using the tables in NBS Handbook 69 (5) as outlined in the Statement of Basis and Purpose. The ICR? model on alkaline earth metabolism indicates that for equal intakes the 50—year dose to bone surface from Ra—228 is significantly greater than that from Ra—226. Experimental data used in the 1972 UNSCEAR report supports this viewpoint. Since radium carcinogenicity Is associated with the dose to bone surfaces, it is likely that Ra—228 is more of a health risk than Ra—226. The measured relative biological effectiveness of Ra—22 8 to Ra—226 in dogs appears to be 2:1 when death via osteosarcomas is used as an end * Assumes quality factor of 10. ------- 111—39 point. While the relative carcinogenicity of Ra—228 to Ra—226 may not be as great in man as in dogs, it is prudent to assume that ingested Ra—228 is at least as dangerous as Ra—226. Treatment Treatment techniques to remove Ra-226 are assumed to be equally sufficient for the removal of Ra—228, Ra-223 and Ra— 22k. Precipitative lime softening, ion exchange and reverse osmosis are the methods of choice. Guidance Since treatment technology exists to readily remove substantial quantities of radium from water, only exemptions for radium contaminants need be granted. No provision is made for variances. Exemptions for supplies having water concentrations of gross alpha activity up to 30 pCi/i are justified on the same basis as that provided for Ra-226 and Ra—228 in Part A above. If a thorough analysis of the water is performed to identify the alpha—emitting radionuclides, exemptions may be appropriate for limited time periods if the dose to bone from all alpha particle emitters, including Ra—226, is less than 300 mrem per year even though the gross alpha activity exceeds 30 pCi/i. 3. Man—Made Beta and Photon Emitters (k mrem per year) Occurrence Numerous man—made beta and photon emitters exist in drinking water as a result of nuclear atmospheric testing; disposal of radiopharmaceuticals from hospitals and research institutions; the nuclear power industry, and from the development of weapons. Since the Nuclear Test Ban Treaty of 1963, there has been a significant decrease in the corresponding radioactivity in surface water. With the development of more medical facilities and procedures requiring radiopharmaceuticals, the release of these radionuclides will probably continue to increase. Assuming a projected increase in energy requirements more beta and photon emitters will undoubtedly be released from the nuclear fuel cycle. Strontium—90 and tritium are two among many radionu— clides of concern in surface waters. Current data suggests that Sr—90 in surface waters run about 1 pCi/i while tritium in surface water rarely exceeds 1000 pCi/i (6). ------- 111 1 10 Health Effects Specific concentrations of radionuclides in drinking water, (pCi/i) which are expected to result in a k mrem/year dose to the critical organ or total body where two liters are consumed per day, are specified in Appendix B - Radionuclides of the National Interim Primary Drinking Water Regulations (6). The NAS—BEIR risk estimates, using the 1976 U.S. population, would suggest that the incremental population risk of a fatal cancer via lifetime exposures resulting in a total body dose rate of mrem/year ranges from about O. t—2 per million people exposed per year, depending on whether the absolute or relative risk model is used (6). The risk from the ingestion of water containing higher amounts of radioactivity would result in proportion- ally higher fatal cancers. Non—fatal cancers and genetic disorders will also be increased with higher exposures. Treatment Treatment for the removal of beta or gamma emitters should be based upon chemical rather than radioactive characteristics of the contaminant. Ion exchange and reverse osmosis can remove a broad spectrum of ions and molecules from water, and consequently are the methods of choice. Some radionuclides, like tritium oxide, are not removable by any practical water treatment process. Guidance Neither variances or exemptions should be necessary except in cases of malpractice. In cases where a water supply has been contaminated via chronic or intermittent releases, a variance or exemption may be necessary for a limited period of time to insure an uninterrupted supply of water for drinking and other purposes. Current federal guidance for transient rate of intake provides limitations on food and water intake that are comparable to an annual dose equivalent of 50 mrem/year and contain a recommendation that for transient situations the dose should be averaged over one year (26 FR 9057). The variance and exemption limitation shall not exceed 50 mrem/- year to any organ from radioactivity in finished drinking water (12 times EPA k mrem/year standard). The maximum dose commitment for any one day from radioactivity in drinking water shall not exceed 10 mrem. ------- III— k 1 The 50 mrem/year limitation can be assumed to be met if at least one of the following analytical procedures results in a screening level concentration(s) of less than those specified below: Gross beta with iodine precipitated - 0 pCi/i Gross beta without iodine precipitated — 100 pCi/i (Separate radioiodine tests may be needed) Should the screening level be exceeded a complete radiochemical analysis may be used to determine whether or not the finished drinking water exceeds the 50 mrem/year limitation. For continuous intake, concentrations of a single man—made radionuclide yielding 50 mrem/year to any specific organ can be found by multiplying by 12 the concen- tration listed in the National Interim Primary Drinking Water Regulations (NIPDWR), EPA—570/9—76—003, Appendix B. When more than one radioriuclide is present, instructions for limiting their sums are given on page 153 of the NIPDWR, Appendix B. For continuous intake, an annual dose rate of 50 mrem results from each of the following concentrations: Strontium—90 100 pCi/i Strontium—89 1,000 pCi/i Cesium—137 2,000 pCi/i Iodine—131 kO pCi/i Radiochemical identification will be required to determine if the individual dose commitment from one day’s intake (2 liters) exceeds 10 mrem. A 10 mrem dose commit- ment results from each of the following concentrations:’ Strontium—9O 7,000 pCi/i Strontium—B9 70,000 pCi/i Cesium—137 200,000 pCi/i Iodine—131 3,700 pCi/i Some acute contaminating events can lead to immediate exposures that will cause relatively high doses over an extended period of time. The granting of exemptions is not amenable to emergency conditions following large accidents. In such cases, the appropriate controlling authority should impose protective actions (29 FR 12056). Protective actions are appropriate when the health benefits associated with the reduction in exposure to be achieved are sufficient to offset the undesirable features of the protective action (30 FR 6953). Such balancing must be made on a case-by—case sis, probably in consultation with several Federal and State agencies, since the impact of food, air, water and * Concentratons causing a 10 millirem dose commitment are 9000 times those given in Appendix B of NIPDWR. ------- 111—42 possible direct radiation must be considered in selecting the appropr iate action level for a particular situation ( O FR 5959k). A Federal Task Force is currently reviewing emergency response planning for radiological incidents. As protective action guides are developed under this program, additional guidance to the States on the granting of variances and exemptions may be forthcoming.* * Note FDA Proposal — Federal Register , Vol. No. 242, pages 58790—58800. ------- I I I— l 3 REFERENCES (1) “The Effects on Population of Exposure to Low Levels of Ionizing Radiation” (BEIR Report), National Academy of Sciences, National Research Council, Washington, D.C., 1972. (2) “Drinking Water and Health,” Safe Drinking Water Committee, National Academy of Sciences, National Research Council, Washington, D.C., 1977. (3) “Determination of Radium Removal Efficiencies in Water Treatment Processes,” U.S. EPA (ORD/TAD—76—5), Washington, D.C. (II) “Treatment Techniques for the Removal of Radioactive Contaminants from Drinking Water,” Gary S. Logsdon, Health Physics 35(6):918. (5) “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and Water for Occupational Exposure,” NBS Handbook 69, Department of Congress, revised 1963. (6) National Interim Primary Drinking Water Regulations,” U.S. EPA (EPA—570/9—7 6 —0O3, ODW), Washington, D.C. ------- SECTION IV VARIANCE AND EXEMPTION PROCEDURES COMPLIANCE SCHEDULE The issuance of a compliance schedule is an integral part of the procedure that must be followed by a primacy agency that grants a variance or an exemption from an MCL. In fact, Sections 1 4 15(a)(1)(D) and 1 t16(b)(3) of the Act require that any variance or exemption be conditioned upon compliance by the public water system with the prescribed schedule. The requirements of each schedule must then be enforceable by the primacy State under its laws and may be enforced under Section 1k14 of the Act as if such require- ments were part of’ the National Primary Drinking Water Regulations. Sections 1 1 415(a)(1)(A) and 1’116(b)(1) require that the compliance schedule be prescribed within one year of the date the variance or exemption is granted {See also O CFR S1Lt2.k3(g) and S1 42.53(d)j. Those sections of the Act further require that such a schedule provide for: 1. compliance (including increments of progress) by the public water system with each contaminant level requirement with respect to which the variance or exemption is granted as expeditiously as practicable; and 2. implementation by the public water system of such control measures as the primacy agency may require for each contaminant, subject to each contaminant requirement, during the period ending on the date compliance with such requirement is required. Thus, it is expected that a compliance schedule will include all steps necessary to achieve compliance with appropriate milestone dates to ensure that the public water system is making diligent efforts to bring itself into compliance as expeditiously as practicable. In the case of a variance, the compliance schedule should include, as a minimum, the following specific dates, where appropriate: (i) Date by which arrangement for alternative raw water source or improvement of existing raw water source will be completed; (ii) Date of initiation of the connection of the alternative raw water source or improvement of existing raw water source; and ------- IV- 2 (iii) Date by which final compliance is to be achieved. If either a variance or exemption is granted, the compliance schedule should include appropriate interim measures including control of’ the contamination source and other means designed to minimize the danger of exposure for all persons or at least for particularly susceptible per- sons. These may include interim treatment measures, notification to physicians and susceptible individuals, increased public health surveillance and provision of drinking water through alternative sources, such as bottled water, where necessary. FACTORS TO BE CONSIDERED Since the completion of various steps necessary to achieve compliance will depend on a number of factors, it is appropriate to consider each factor and its relative impor- tance to a given situation. The following factors should be considered by the primacy agency in prescribing a compliance schedule, keeping In mind that compliance should be achieved as expeditiously as practicable. The established time frames must above all be reasonable relative to the particu- lar circumstances. 1. Health and safety of’ consumers of water : It is of’ utmost importance to consider the acute or chronic health effects that might be Induced by an unduly long compliance schedule. 2. Technical (a) Time to study the problem and recommend a solution; (b) Time for user participation and Input; Cc) If modifications to existing treatment facilities or construction of new facilicites are indicated by the studies, the time to complete design and to obtain necessary permits, to let contracts and work out contractual arrangements, and to install equipment should be considered; (d) Time for delays due to Inclement weather or labor problems; and Ce) Time for testing and start—up. ------- IV-3 3. Economic The time necessary to arrange financing of the contemplated improvements should be considered in setting up the milestone dates in the compliance schedule. I. Legal and Administrative Unavoidable delays due to legal and administrative requirements should be anticipated and provided for in the compliance schedule. 5. Other Other pertinent and/or unique factors which bear on the water system’s compliance schedule should be considered. 6. Extensions Extensions to an established compliance schedule should be granted by the primacy agency only when the public water system has demonstrated good cause, is acting in good faith, and the circumstances otherwise warrant. In the case of an exemption, extensions cannot be granted beyond the statutory deadlines. Please note two typographical errors in O CFR Part 1 2: 1. 4O CFR 1L 2i 3(b)(1) — The reference in the last line of the paragraph should be changed from “Section 1l .1.1414” to “Section 2. 4O CFR 1L 2.51I(d) — The next to the last line of the paragraph should be changed from “5 days” to “15 days”. Compliance Deadlines In addition to considering the practical constraints that will bear upon the length of a compliance schedule as described above, the primacy agency must also be guided by the statutory time limits established under the Safe Drink- ing Water Act. No compliance schedule may extend beyond the dates established under the Act. Nor should it be so short that the necessary steps taken to achieve compliance cannot be completed due to unavoidable technical, legal or admini- strative delays. ------- IV_14 With respect to variances, the Act contains no statutorily mandated deadline by which time compliance must be achieved. Due to the kind of problem variances were intended to address, the establishment of a specific time—limit in any given situation will depend largely on the availability of an alternative raw water source or the existence of new treatment technologies with greater removal efficiencies which are capable of achieving the established maximum contaminant levels. Nevertheless, compliance dead- lines should be imposed by the primacy agency whenever it is feasible to do so. In any event, compliance should be required to be achieved as expeditiously as practicable by incorporating such language into the variance. The schedule may therefore specify an indefinite time period for compliance until a new and effective treatment technology is developed at which time a new compliance schedule will be prescribed by the primacy agency. Periodic evaluations of issued variances should be conducted to ensure that the timeframes are still reasonable, no unreasonable risk to health is involved and the basic conditions surrounding their issuance continue to exist. Unlike variances, in the case of exemptions, Section 11416 clearly requires that compliance schedules must contain a final compliance deadline of not later than January 1, 1981 (or January 1, 1983, if the supplier of the public water system has entered into an enforceable agreement to become part of a regional water system). Where it is prac- ticable for a public water system to come into compliance earlier than the statutory deadline, the exemption schedule should specify the appropriate earlier compliance date. Whereas in most cases, compliance will be achievable within the statutory timefraine, in a relatively few number of cases, EPA recognizes that compliance will not be feasible by January 1, 1981, nor will regionalization be feasible to allow an extension of the deadline to January 1, 1983. The timeframe also becomes increasingly critical as the National Interim Primary Drinking Water Regulations are amended. In light of these concerns, EPA is proposing amendments to Section 11416 of the Safe Drinking Water Act which would extend the compliance deadlines for exemptions beyond the 1981 and 1983 dates presently specified. During this period, before Congress can take legislative action with regard to the exemption deadlines, the primacy agency must establish exemption schedules consistent with the existing statutory provisions. In those cases where a public water system can demonstrate that the 1981 deadline ------- IV- 5 cannot be met despite all reasonable efforts to do so, and has demonstrated good faith efforts to comply with the regulations since they were promulgated, the primacy agency’s enforcement discretion should be carefully exercised. In the short term, it may also be possible for the primacy agency to delay issuance of the compliance schedule for one year following the issuance of the exemption or to delay inclusion of a final compliance deadline in the schedule for that year, at which point in time further legislative guidance will be forthcoming. This guidance document will be revised to reflect any statutory amendments at that time. ------- WAGRAM I VAR AEE FROM AN MC I . ISSUED BY A STATE p ------- DIAGRAM 2 VARI*N E FROM A TREATMENT TECHNIQUE MSUED BY A STATE In ------- DIAGRAM 3 EXEMPTIONS fROM AN MCI. AND/DR A TREATMENT TECHNIQUE ISSUED BY A STATE NTh ------- 0110011*00 1 StAll 1*100*00— I 111111 to stAll I *1110 1 *00 SO Il - I ..fit.in prn.oro 00*14 C050I (TlV l • SO PUSUC 00*0*0 1 P IStI l 51*0*0 I ISC P II4U*I 1 111514t0140I ( _______________ DIAGRAM 4 EPA ACTION ON VARIANCES AND EXEMPTIONS ISSUED BY A STATE III’A SIl OS 507141 tO mm oc P110 100* ________________ ISP *55* OP 511105 I lOOTS UST 101U I i 1105. *00 OP P 0 5 1 41 ________ ________ I *0S All. 0*04 I 15 1Mh 1105 I mcl lAUSl* TI 5 . 0 4 0 1 * ISUS * IT OP I * 14IS4I ) )IIISIW I 1100 1U44101 ] 1I4 1 1 1 4 1 12 1 )AI 40 r I 114 114 .4 I 111010 l OS SAYS 4001 1 1111 14. 1 ITO ACTIS I S SUVA*J I luia.,uuiict,cp os.l )FlS.IlE l. ) 5 1 0 5TSI I U OT IC S OPPVILIC I I * 501 5 I E*ALu* lIsIzI su’ l .i fr,si.siviiwoc UIA lIAL.IAN IIsluIua,om•• I ‘ ° o.IVAAI*1C 100 5 10 — I on 55511100*5* on I 01*0101 I ITO I 100 * 01*11 S,* ci ovi r*n1 IeaPsIL*.nIcIil ...j SPOPU SUII 4u I I IP00 5 1tI Isn I F 1 (0*1 5510 I I I , 14t 14 .I4II4c) I I 14154.4.1*5) I I t4iooiw I 1I4 1041 1 12 1 15 1 I I 114144410111) I . 1 1N1*1YS j 1100 50 50 5*14 I I 14 154i*l)IF ) I t 4IK . 4 It )$t o I I I4 1 14 0 1H 5 14.I u sn ou i v jo.. IJ 10* 1*01140 ost,s 14*10* I 1* 144 4 ) 1 1) I i 1415 14) 11) ____________ 4lCp5l4tu* I I I 4ICF iI4U244 IICFSI4W4.) I 40015l4W 4) 1 — lIS 015051 AVAlIASLI coo .uoiic IS11tC1 $ * 001 1*100 144*0 011 20.1111 coo 01111 11401*07101:11*10011101*11*11001 *1( 1*11 TIIINNIALLY. (PA 51111140 5 151115$ OF *5000 I 14 1S4 1 1)4)ll )) ))))I) I 1410 14)12*5) Ii) PNOTLY 44(05 14U3’. ) )4) PA NOTIPISI I 110011 IC0l $0VLl 11*75 *111 5 I TA IlS IPPICT I0 1LY •14154d 5 1)4S) S 14 154i 1)1)45)4lll) I __________________ I 14 1 54.HI) ) 5I)4) I i I IIII4II IIIC) I (PA POOMULSATU 40 (Fl 141.134.411) L J O IVOC*TIOI All 0(011*01(000111 1(1115*0 550*11 I 44 1 14.)(IHl)iIHII ) I 14 1514h01)SIlS ) I I CFS 141.231.101 ITATI 1*001 (PA 5(511100 Mc I) *040 1*1 1 CATION OP P110001* CIS OICTIVI To 0*51451*1 *11400 IIIwfl001 0* * 14 1 14. 5I5I)UA) 1(0 10 111 * 141144)0111) I 14 1 14.))1)11 10 1 1 1 45 (PR 101.14 5141 1440*1) ------- DIAGRAM 5 VARIANCE FROM AN MCL ISSUED BY EPA EPA NECINDI I J EPA GPOOES NOTICE OF f NEGUESI PROPOSED I A COMAIIAHCI HEARINGS OPPOSIUWITI RECEIVES NOT HELD WIT N WITHIN ___________ ___________ I WITHIN EPA POILIOHES I I HEARING EPA GIVES PUNLIC VARIANCE I SCHEDULE EESI POll HEARING ___________ ___________ ___________ GROCHEDULS OR PROPOSED SA n ._... L....W_ [ UHLICH(ANIH_j THAN 40 CNN 14244(41 Z DAYS ONE YUAN VARIANCE OH 44 GIN 142.44).) L CER l4L44( _______________ SCHEDULE __________________ ___________________ 44 CNN 142.45 I N I 4 Z. 4 J _______________ ________________ 40 CFR 142.44)4) PROPOSER VARIANCE EPA DETERMINES HEARINGS NOT WI RAYS AFTER HOTICE OR SCHEDULE HE COMES NECESSARY EFFECTIVE OPPOETUNSTY FOR HEARING 44 CPU 142:40 44 CNN 142.44)11 40 CFN 1424411) -44 - * EPA NOTIFIES WIT IAR l N AAPLICANT IS I SUPPLIES I j DENIES [ NOITIER MODEST I ________________ DiNT (EiGHT TO INFORIHATIGI DAVE • 14242 1 j 551MIIYRS WI DAYS 44 CNN 142.4W.) 40 CNN I WHITING CI APPLICATION EPA II SUPPLIER I SF WATER, WITH WITHIN WI DAYS 424W41 OCCUMGN1 ER WIGS AND 1INIEDA P PLI PROPOUES COMPLIANCE I EEi IN WRITING DII . . . . SCHEDULE IFWUPUEAL ID ENANTI WITHIN MS ___ RIOSIUT WITH WILl IRS CONEIT(DNS )b,( ,(.).lH WI SAYD L ! ! I4O.4W Lj 44 CNN 14241).) ------- OI MM I FIIOM ThEATMENT TEC*INIOUES ISSUED BY EPA ------- DIAGRAM 7 EXEMPTIONS FROM MCLS AND TREATMENT TECHNIDUES ISSUED BY EPA ------- SECTION V COMPLIANCE AGREEMENTS As a practical matter there may be a substantial delay between the time that a violation is detected, determination by the water supplier that a variance or exemption is the desired course of action, and a decision is made by the primacy agency to grant or deny the request. In such cases, it may be appropriate for the primacy agency, after it has determined that there is no unreasonable risk to health, to develop and implement a compliance agreement with the water supplier. The compliance agreement should acknowledge that there is no unreasonable risk to health, outline the necessary actions to be taken by the water supplier and EPA in the interim period and allow deviation from the MCL until the variance or exemption is granted or denied by the primacy agency. Such actions may include increased public notice, special notice to physicians and provisions for bottled wa t e r. There is also another situation where a compliance agreement could be utilized. If the primacy agency has determined that there is no unreasonable risk to health and it appears the water supplier can be in accordance with the Interim Primary Drinking Water Regulations within a short time frame (a few months), it is prudent to eliminate the complex variance or exemption process. This allows more flexibility, and reduces the resource demand (i.e., paper- work, manpower), and at the same time, maintains reasonable public health protection. It should be understood that such administrative actions are not explicitly included in the provisions of the Safe Drinking Water Act and care must be exercised to ensure that the conditions of the compliance agreement are as least as stringent as those associated with a variance or exemption. Parties to a compliance agreement should be aware that the protection from enforcement action, including citizen suit, provided by exemptions and variances, is not in effect. * U. S. GOVER1 MENT PRIN1 U G OFFICE 1979 281-147/102 ------- |