Tuesday, May 1, 2007
Part III
Environmental Protection Agency 40 CFR Part 141 Drinking Water: Regulatory Determinations Regarding Contaminants on the Second Drinking Water Contaminant Candidate List—Preliminary Determinations; Proposed Rule
VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24016 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules
ENVIRONMENTAL PROTECTION VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00002 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24017 HRL—health reference level UF—uncertainty factor I. General Information IOC—inorganic compound US—United States of America IRIS—Integrated Risk Information System USDA—United States Department of A. Does This Action Impose Any kg—kilogram Agriculture Requirements on My Public Water L—liter USGS—United States Geological Survey System? LD —an estimate of a single dose that is 50 UST—underground storage tanks None of these preliminary regulatory expected to cause the death of 50 percent VOC—volatile organic compound of the exposed animals; it is derived determinations or the final regulatory I. General Information from experimental data. determinations, when published, will A. Does This Action Impose Any LOAEL—lowest-observed-adverse-effect level impose any requirements on anyone. MAC—mycobacterium avium intercellulare Requirements on My Public Water Instead, this action notifies interested MCL—maximum contaminant level System? parties of the availability of EPA’s B. What Should I Consider as I Prepare My MCLG—maximum contaminant level goal preliminary regulatory determinations Comments for EPA? mg—milligram, one-thousandth of a gram for 11 of the 51 contaminants listed on mg/kg—milligrams per kilogram body weight II. Purpose, Background and Summary of mg/kg/day—milligrams per kilogram body This Action CCL 2 and seeks comment on these weight per day A. What Is the Purpose of This Action? preliminary determinations. This action mg/L—milligrams per liter B. Background on the CCL and Regulatory also provides an update on the Agency’s mg/m3—milligrams per cubic meter Determinations review of perchlorate and methyl MRL—minimum or method reporting limit C. Summary of the Approach Used To tertiary butyl ether (MTBE). (depending on the study or suvey cited) Identify and Evaluate Candidates for MTBE—methyl tertiary butyl ether B. What Should I Consider as I Prepare Regulatory Determination 2 My Comments for EPA? MTP—monomethyl-2,3,5,6- D. What Are EPA’s Preliminary tetrachloroterephthalate Determinations and What Happens Next? You may find the following N—number of samples E. Supporting Documentation for EPA’s suggestions helpful for preparing your NAS—National Academies of Sciences NAWQA—National Water Quality Preliminary Determinations comments: Assessment (USGS Program) III. What Analyses Did EPA Use To Support 1. Explain your views as clearly as NCEH—National Center for Environmental the Preliminary Regulatory possible. Health (CDC) Determinations? 2. Describe any assumptions that you NCFAP—National Center for Food and A. Evaluation of Adverse Health Effects used. Agricultural Policy B. Evaluation of Contaminant Occurrence 3. Provide any technical information NCI—National Cancer Institute and Exposure and/or data you used that support your NCWS—non community water system IV. Preliminary Regulatory Determinations views. ND—not detected (or non detect) A. Summary of the Preliminary Regulatory 4. If you estimate potential burden or NDWAC—National Drinking Water Advisory Determination costs, explain how you arrived at your Council B. Contaminant Profiles NHANES—National Health and Nutrition estimate. 1. Boron 5. Provide specific examples to Examination Survey (CDC) 2. and 3. Mono- and Di-Acid Degradates of NIRS—National Inorganic and Radionuclide illustrate your concerns. Dimethyl Tetrachloroterephthalate 6. Offer alternatives. Survey (DCPA) 7. Make sure to submit your NIS—sodium iodide symporter 4. 1,1-Dichloro-2,2-bis(p-chlorophenyl) NOEL—no-observed-effect-level ethylene (DDE) comments by the comment period NOAEL—no-observed-adverse-effect level 5. 1,3-Dichloropropene (1,3-DCP; Telone) deadline. NPS—National Pesticide Survey 6. and 7. 2,4- and 2,6-Dinitrotoluenes (2,4- 8. To ensure proper receipt by EPA, NQ—not quantifiable (or non quantifiable) identify the appropriate docket NRC—National Research Council and 2,6-DNT) 8. s-Ethyl dipropylthiocarbamate (EPTC) identification number in the subject line NPDWR—National Primary Drinking Water on the first page of your response. It Regulation 9. Fonofos NTP—National Toxicology Program 10. Terbacil would also be helpful if you provided OA—oxanilic acid 11. 1,1,2,2-Tetrachloroethane the name, date, and Federal Register OW—Office of Water V. What Is the Status of the Agency’s citation related to your comments. Evaluation of Perchlorate? OPP—Office of Pesticide Programs II. Purpose, Background and Summary PCR—Polymerase Chain Reaction A. Sources of Perchlorate PGWDB—pesticides in ground water data B. Health Effects of This Action base C. Occurrence in Water, Food, and This section briefly summarizes the PWS—public water system Humans. purpose of this action, the statutory RED—Reregistration Eligibility Decision D. Occurrence Studies on Perchlorate in requirements, previous activities related RfC—reference concentration Human Urine, Breast Milk, and Amniotic to the Contaminant Candidate List and RfD—reference dose Fluid RSC—relative source contribution regulatory determinations, and the E. Status of the Preliminary Regulatory approach used and outcome of these SAB—Science Advisory Board Determination for Perchlorate SDWA—Safe Drinking Water Act preliminary regulatory determinations. F. What Are the Potential Options for SOC—synthetic organic compound Characterizing Perchlorate Exposure and A. What Is the Purpose of This Action? SVOC—semi-volatile organic compound Proceeding With the Preliminary T3—triiodothyronine The Safe Drinking Water Act (SDWA), T4—thyroxine Regulatory Determination for as amended in 1996, requires EPA to Perchlorate? TDS—Total Diet Study (FDA) publish a list of currently unregulated Tg-DNT—technical grade DNT G. Next Steps VI. What About the Remaining CCL 2 contaminants that may pose risks for TPA—2,3,5,6-tetrachchloroterephthalic acid drinking water (referred to as the TRI—Toxics Release Inventory Contaminants? TSH—thyroid stimulating hormone A. Metolachlor Contaminant Candidate List, or CCL) TT—treatment technique B. Methyl tertiary-butyl ether and to make determinations on whether UCM—Unregulated Contaminant Monitoring C. Microbial Contaminants to regulate at least five contaminants UCMR 1—First Unregulated Contaminant VII. EPA’s Next Steps from the CCL with a national primary Monitoring Regulation VIII. References drinking water regulation (NPDWR) VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00003 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24018 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules (section 1412(b)(1)). The 1996 SDWA water systems with a frequency and at were Acanthamoeba, aldrin, dieldrin, requires the Agency to publish both the levels of public health concern; and hexachlorobutadiene, manganese, CCL and the regulatory determinations (c) In the sole judgment of the metribuzin, naphthalene, sodium, and every five years. The purpose of this Administrator, regulation of such sulfate. The Agency determined that a action is to present (1) EPA’s contaminant presents a meaningful national primary drinking water preliminary regulatory determinations opportunity for health risk reduction for regulation was not necessary for any of for 11 candidates selected from the 51 persons served by public water systems. these 9 contaminants. The Agency If EPA determines that all three of contaminants listed on the second CCL issued guidance on Acanthamoeba and these statutory criteria are met and (CCL 2), (2) the process and the health advisories for magnesium, makes a final determination that a rationale used to make these sodium, and sulfate. determinations, and (3) a brief summary national primary drinking water of the supporting documentation. This regulation is needed, the Agency has 24 The decision-making process that action also includes a request for months to publish a proposed MCLG EPA used to make its regulatory comment(s) on the Agency’s and NPDWR. After the proposal, the determinations for CCL 1 was based on preliminary determinations. Agency has 18 months to publish and substantial expert input and promulgate a final MCLG and NPDWR recommendations from different groups The 11 regulatory determination 3 contaminants candidates discussed in (SDWA section 1412(b)(1)(E)). including stakeholders, the National 2. The First Contaminant Candidate this action are boron, the dacthal mono- Research Council (NRC) and NDWAC. List (CCL 1). Following the 1996 SDWA and di-acid degradates, 1,1-dichloro-2,2- In June 2002, EPA consulted with the Amendments, EPA sought input from bis(p-chlorophenyl)ethylene (DDE), 1,3- Science Advisory Board (SAB) Drinking the National Drinking Water Advisory dichloropropene, 2,4-dinitrotoluene, Water Committee and requested its Council (NDWAC) on the process that 2,6-dinitrotoluene, s-ethyl review and comment on whether the should be used to identify contaminants propylthiocarbamate (EPTC), fonofos, protocol EPA developed, based on the for inclusion on the CCL. For chemical terbacil, and 1,1,2,2-tetrachloroethane. NDWAC recommendations, was contaminants, the Agency developed consistently applied and appropriately B. Background on the CCL and screening and evaluation criteria based documented. SAB provided verbal Regulatory Determinations on recommendations from NDWAC. For feedback regarding the use of the NRC microbiological contaminants, NDWAC 1. Statutory Requirements for CCL recommended that the Agency seek and NDWAC recommendations in EPA’s and Regulatory Determinations. The external expertise to identify and select decision criteria for making its specific statutory requirements for the potential waterborne pathogens. As a regulatory determinations. SAB CCL and regulatory determinations can result, the Agency convened a workshop recommended that the Agency provide be found in SDWA section 1412(b)(1). of microbiologists and public health a transparent and clear explanation of The 1996 SDWA Amendments require experts who developed criteria for the process for making regulatory EPA to publish the CCL every five years. screening and evaluation and determinations. The Agency took SAB’s The CCL is a list of contaminants that subsequently developed an initial list of recommendation into consideration and are not subject to any proposed or potential microbiological contaminants. further explained the CCL 1 regulatory promulgated NPDWRs, are known or The first CCL process benefited from determination evaluation process in the anticipated to occur in public water considerable input from the NDWAC, July 18, 2003 (68 FR 42898 (USEPA, systems (PWSs), and may require the scientific community, and the 2003a)) notice and in the supporting regulation under SDWA. The 1996 public through stakeholder meetings documentation. SDWA Amendments also direct EPA to and the public comments received on determine whether to regulate at least EPA has used the same approach to the draft CCL published on October 6, develop the regulatory determinations five contaminants from the CCL every 1997 (62 FR 52193 (USEPA, 1997a)). five years (within three and one-half discussed in this action. While this EPA published the final CCL, which action includes a short description of years after publication of the final list). contained 50 chemical and 10 the decision process used to make In making regulatory determinations, microbiological contaminants, on March regulatory determinations (section II.C), SDWA requires EPA to publish a 2, 1998 (63 FR 10273 (USEPA, 1998a)). 1 a more detailed discussion can be found Maximum Contaminant Level Goal A more detailed discussion of how EPA 2 in the 2002 and the 2003 Federal (MCLG) and promulgate an NPDWR developed CCL 1 can be found in the for a contaminant if the Administrator 1997 and the 1998 Federal Register Register notices (67 FR 38222 (USEPA, determines that: notices (62 FR 52193 (USEPA, 1997a) 2002a) and 68 FR 42898 (USEPA, (a) The contaminant may have an and 63 FR 10273 (USEPA, 1998a)). 2003a)). adverse effect on the health of persons; 3. The Regulatory Determinations for 4. The Second Contaminant (b) the contaminant is known to occur CCL 1. EPA published its preliminary Candidate List (CCL 2). The Agency or there is a substantial likelihood that regulatory determinations for a subset of published its draft CCL 2 Federal the contaminant will occur in public contaminants listed on CCL 1 on June 3, Register notice on April 2, 2004 (69 FR 2002 (67 FR 38222 (USEPA, 2002a)). 17406 (USEPA, 2004a)) and the final 1 The MCLG is the ‘‘maximum level of a The Agency published its final CCL 2 Federal Register notice on contaminant in drinking water at which no known regulatory determinations on July 18, February 24, 2005 (70 FR 9071 (USEPA, or anticipated adverse effect on the health of 2003 (68 FR 42898 (USEPA, 2003a)). persons would occur, and which allows an 2005a)). The CCL 2 carried forward the adequate margin of safety. Maximum contaminant EPA identified 9 contaminants from the 51 remaining chemical and microbial level goals are nonenforceable health goals’’ (40 60 contaminants listed on CCL 1 that contaminants that were listed on CCL 1. CFR 141.2). had sufficient data and information 2 An NPDWR is a legally enforceable standard available to make regulatory 5. The Regulatory Determinations for that applies to public water systems. An NPDWR determinations. The 9 contaminants CCL 2. This current action discusses sets a legal limit (called a maximum contaminant EPA’s preliminary determinations for 11 level or MCL) or specifies a certain treatment technique (TT) for public water systems for a 3 The statute authorizes a nine month extension of the 51 contaminants listed on the specific contaminant or group of contaminants. of this promulgation date. CCL 2. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00004 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24019 C. Summary of the Approach Used To CCL 2 contaminants are candidates for Identify and Evaluate Candidates for regulatory determinations and the Regulatory Determination 2 SDWA statutory criteria considered in Figure 1 provides a brief overview of making the regulatory determinations. the process EPA used to identify which BILLING CODE 6560–50–P BILLING CODE 6560–50–C information/data, the Agency available to identify any potential In identifying which CCL 2 considered whether an Agency- adverse health effect(s) and derive an contaminants are candidates for approved health risk assessment 4 was estimated level at which adverse health regulatory determinations, the Agency effect(s) are likely to occur. With regards considered whether sufficient 4 Health information used for the regulatory to sufficient occurrence information/ information and/or data were available determinations process includes but is not limited data, the Agency considered whether to characterize the potential health to health assessments available from the Agency’s information/data were available to effects and the known/likely occurrence Integrated Risk Information System (IRIS), the Agency’s Office of Pesticide Programs (OPP) in a Agency for Toxic Substances and Disease Registry in and exposure from drinking water. Reregistration Eligibility Decision (RED), the (ATSDR). With regards to sufficient health effects National Academy of Sciences (NAS), and/or the VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00005 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS EP01MY07.050 24020 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules evaluate and give a generally approach used to analyze the E. Supporting Documentation for EPA’s representative idea of known and/or occurrence information/data. Preliminary Determinations likely occurrence in public water (3) Third statutory criterion—In the For this action, EPA prepared several systems. If sufficient information/data sole judgment of the Administrator, support documents that are available for were available to characterize adverse does regulation of the contaminant review and comment in the EPA Water human health effects and known/likely present a meaningful opportunity for Docket and at http:// occurrence in public water systems, the health risk reduction for persons served www.regulations.gov. These support Agency identified the contaminant as a by public water systems? EPA evaluated documents include: potential candidate for regulatory the potential health effects and the VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00006 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24021 candidate contaminant may have an be carcinogenic to humans, EPA preliminary negative determination for adverse effect on public health. This generally calculates a reference dose each of these 6 compounds, the Agency section describes the overall process the (RfD). A RfD is an estimate of a daily determined that it was not necessary to Agency used to evaluate health effects further evaluate the RSC in making the oral exposure to the human population regulatory determination. information, the approach used to (including sensitive subgroups) that is estimate a contaminant HRL (a likely to be without an appreciable risk As discussed in section IV.B.2 and 3, benchmark against which to conduct the of deleterious effects during a lifetime. the HRL for the two dacthal degradates initial evaluation of the occurrence It can be derived from either a ‘‘no- is based on the HRL value derived for data), and the approach used to identify observed-adverse-effect level’’ (NOAEL), the DCPA parent following the guidance and evaluate information on hazard and a ‘‘lowest-observed-adverse-effect level’’ provided by EPA’s Office of Pesticide dose-response for the contaminants (LOAEL), or a benchmark dose, with Programs. under consideration. More specific uncertainty factors applied to reflect 3. Sources of Data/Information for information about the potential for limitations of the data used. Health Effects. EPA used the best adverse health effects for each The Agency uses uncertainty factors available peer-reviewed data and contaminant is presented in section IV.B (UFs) to address uncertainty resulting analyses in evaluating adverse health of this action. from incompleteness of the toxicological effects. Peer-reviewed health-risk There are two different approaches to database. The individual UFs (usually assessments were available for all the derivation of an HRL. One approach applied as integers of 1, 3, or 10) are chemicals considered for regulatory determinations from the Agency’s is used for chemicals that cause cancer multiplied together and used to derive Integrated Risk Information System and exhibit a linear response to dose the RfD from experimental data. (IRIS) Program5 and/or the Office of and the other applies to noncarcinogens Individual UFs are intended to account Pesticide Programs (OPP) Reregistration and carcinogens evaluated using a non- for: Eligibility Decisions (RED).6 Table 1 linear approach. (1) The variation in sensitivity among summarizes the sources of the health 1. Use of Carcinogenicity Data for the the members of the human population assessment data for each chemical Derivation of a Health Reference Level. (i.e., intraspecies variability); under regulatory determination For those contaminants considered to be (2) the uncertainty in extrapolating consideration. The Agency performed a likely or probable human carcinogens, animal data to humans (i.e., interspecies literature search for studies published EPA evaluated data on the mode of variability); action of the chemical to determine the after the IRIS or OPP health-risk (3) the uncertainty in extrapolating assessment was completed to determine method of low dose extrapolation. from data obtained in a study with less- When this analysis indicates that a if new information suggested a different than-lifetime exposure to lifetime outcome. The Agency collected and linear low dose extrapolation is exposure (i.e., extrapolating from appropriate or when data on the mode evaluated any peer-reviewed subchronic to chronic exposure); of action are lacking, EPA uses a low publications identified through the (4) the uncertainty in extrapolating dose linear extrapolation to calculate literature search for their impact on the from a LOAEL rather than from a risk-specific doses. The risk-specific RfD and/or cancer assessment. In cases NOAEL; and/or doses are the estimated oral exposures where the recent data indicated that a (5) the uncertainty associated with an associated with lifetime excess risk change to the existing RfD or cancer incomplete database. levels that range from one cancer in ten assessment was needed, the updated For boron, the dacthal (DCPA) mono thousand (10-4) to one cancer in a OW assessment, as described in the and di acid degradates, s-ethyl million (10-6). The risk-specific doses health effects support document, was dipropylthiocarbamate (EPTC), fonofos (expressed as mg/kg of body weight per independently peer-reviewed. All day) are combined with adult body and terbacil, EPA derived the HRLs quantitative cancer assessments weight and drinking water consumption using the RfD approach as follows: conducted under the Guidelines for data to estimate drinking water HRL = [(RfD x BW)/DWI] x RSC Carcinogen Risk Assessment (51 FR concentrations corresponding to this Where: 33992 (USEPA, 1986)) were updated risk range. EPA generally used the one- RfD = Reference Dose using the Guidelines for Carcinogen in-a-million (10-6) cancer risk in the BW = Body Weight for an adult, assumed to Risk Assessment (USEPA, 1999a) as initial screening of the occurrence data be 70 kilograms (kg) directed in the November 2001 (66 FR for carcinogens evaluated using linear DWI = Drinking Water Intake, assumed to be 59593 (USEPA, 2001a)) Federal Register low dose extrapolation. Five of the 2 L/day (90th percentile) notice. eleven contaminants discussed in this RSC = Relative Source Contribution, or the In March 2005, EPA updated and action had data available to classify level of exposure believed to result from finalized the Cancer Guidelines and a them as likely or probable human drinking water when compared to other Supplementary Children’s Guidance, sources (e.g., food, ambient air). A 20 carcinogens. These five are also the only percent RSC is being used to estimate the 5 contaminants for which low dose linear HRL and screen the occurrence data IRIS is an electronic EPA database (http:// extrapolations were performed. These because it is the lowest and most www.epa.gov/iris/index.html) containing peer- reviewed information on human health effects that five are p,p- conservative RSC used in the derivation may result from exposure to various chemicals in dichlorodiphenyldichloroethylene of an MCLG for drinking water. For each the environment. These chemical files contain (DDE), 1,3-dichloropropene (1,3-DCP or of the 6 aforementioned non- descriptive and quantitative information on hazard Telone), 2,4-dinitrotoluene, 2,6- carcinogenic compounds for which the identification and dose response, RfDs for chronic dinitrotoluene, and 1,1,2,2- Agency has made a preliminary noncarcinogenic health effects, as well as slope factors and unit risks for carcinogenic effects. tetrachloroethane. The remaining 6 regulatory determination in this action, EPA used the RfD in conjunction with a 6 The OPP is required under the Federal contaminants have not been identified 20 percent RSC to derive a conservative Insecticide Fungicide and Rodenticide Act (FIFRA) as known, likely or probable HRL estimate and perform an initial to review all pesticides registered prior to 1984 and carcinogens. determine whether to reregister them for continued screening of the drinking water use. The results of the reregistration analysis are 2. Use of Non-carcinogenic Health occurrence data. Since the initial included in the REDs. Copies of the REDs are Effects Data for Derivation of an HRL. screening of the occurrence data at this located at the following Web site: http:// For those chemicals not considered to conservative HRL value resulted in a cfpub.epa.gov/oppref/rereg/status.cfm?show=rereg. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00007 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24022 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules which include new considerations for mutagenic mode of action, which would the Proposed Guidelines for Carcinogen mode of action and added guidelines require an extra factor of safety for Risk Assessment (61 FR 17960 (USEPA, related to potential risks due to early children’s health protection. Therefore, 1996a)). The Administrator (USEPA, childhood exposure (USEPA, 2005b; conducting the cancer evaluation using 2005d) has directed that current USEPA, 2005c). EPA updated the earlier the 2005 Cancer Guidelines would not completed assessments can be assessments (based on the 1986 result in any change from the considered to be scientifically sound Guidelines) for DDE, the dinitrotoluenes assessment updated following the 1999 based on the guidance used when the (2,4 and 2,6 as a mixture), and 1,1,2,2- Guidelines. assessment was completed until a new tetrachloroethane following the 1999 The cancer assessment for 1,3- assessment is performed by one of the Guidelines. None of these chemicals dichloropropene was done by OPP and responsible program offices. have been determined to have a IRIS (USEPA, 1998b and 2000a) under TABLE 1.—SOURCES AND DATES OF EPA HEALTH RISK ASSESSMENTS Chemical IRIS Date OPP RED Date Boron ...... X 2004 ...... Dacthal and its mono- and di-acid degradates ...... X 1994 X 1998 1,3-Dichloropropene ...... X 2000 X 1998 DDE ...... X 1988 ...... 2,4-Dinitrotoluene ...... X 1990/1992 ...... 2,6-Dinitrotoluene ...... * X 1990 ...... EPTC ...... X 1990 X 1999 Fonofos ...... X 1991 ** X 1996 Terbacil ...... X 1989 X 1998 1,1,2,2-Tetrachloroethane ...... X 1986 ...... * Applies to a mixture of 98 percent 2,4-dinitrotoluene and 2 percent 2,6-dinitrotoluene. ** Health Risk Assessment; RED not completed due to pesticide cancellation. As noted in section II.E, EPA has occurrence data used to support these information and/or data. A summary of prepared several technical health effects determinations include the following the occurrence data and the results or support documents for the contaminants sources: findings for each of the 11 contaminants considered for this round of regulatory TABLE 2.—PRIMARY SOURCES OF DRINKING WATER OCCURRENCE DATA USED IN THE REGULATORY DETERMINATION PROCESS Primary data sources UCMR 1 Number Contaminant UCM List 1 List 2 NIRS assessment screening Round 1 Round 2 monitoring survey cross section cross section 1 ...... Boron ...... 1 X 2 ...... Dacthal mono- and 3 ...... di-acid degradates ...... X 4 ...... DDE ...... X 5 ...... 1,3-Dichloropropene ...... 2 X X X 6 ...... 2,4-Dinitrotoluene ...... X 7 ...... 2,6-Dinitrotoluene ...... X 8 ...... EPTC ...... X 9 ...... Fonofos ...... X 10 ...... Terbacil ...... X VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00008 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24023 TABLE 2.—PRIMARY SOURCES OF DRINKING WATER OCCURRENCE DATA USED IN THE REGULATORY DETERMINATION PROCESS—Continued Primary data sources UCMR 1 Number Contaminant UCM List 1 List 2 NIRS assessment screening Round 1 Round 2 monitoring survey cross section cross section 11 ...... 1,1,2,2-Tetrachloroethane ...... X X 1 For boron, EPA also considered the results of a study funded by AWWARF (Frey et al., 2004). 2 1,3-Dichloropropene was sampled as a UCM Round 1 and 2 analyte but due to sample degradation concerns the contaminant was re-ana- lyzed using the samples provided by the small systems that participated in the UCMR 1 List 1 Assessment Monitoring. a. The Unregulated Contaminant from 2001 through 2003. Large systems Screening Survey from the participating Monitoring Regulation. In 1999, EPA could conduct one year of monitoring large and small systems. Approximately developed the UCMR program in anytime during the 2001–2003 UCMR 1 2,300 samples were collected for each coordination with the CCL and the period. EPA specified a quarterly contaminant. The UCMR 1 List 2 National Drinking Water Contaminant monitoring schedule for surface water Screening Survey included systems Occurrence Database (NCOD) to provide systems and a twice-a-year, six-month from 48 States, 2 U.S. Territories, and national occurrence information on interval monitoring schedule for ground Tribal lands in 1 EPA Region. EPA used unregulated contaminants (September water systems. The objective of the the occurrence data from this survey to 17, 1999, 64 FR 50556 (USEPA, 1999b); UCMR 1 sampling approach for small evaluate fonofos. March 2, 2000, 65 FR 11372 (USEPA, systems was to collect contaminant EPA analyzed the UCMR 1 List 1 2000b); and January 11, 2001, 66 FR occurrence data from a statistically Assessment Monitoring and List 2 2273 (USEPA, 2001b)). EPA used data selected, nationally representative Screening Survey data to generate the from the UCMR 1 program to evaluate sample of small systems. The small following initial occurrence and occurrence for 9 of the 11 contaminants system sample was stratified and exposure summary statistics: considered for these regulatory population-weighted, and included VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00009 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24024 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules occurrence for 2 of the 11 contaminants with approximately 3.7 million the national occurrence of inorganic considered for these regulatory analytical data points from slightly more contaminants in community water determinations. These two than 27,000 unique PWSs. The UCM systems (CWSs) served by ground water. contaminants are 1,3-dichloropropene Round 1 and 2 national cross-sections EPA used data from NIRS, as well as a and 1,1,2,2-tetrachloroethane. represent significantly large samples of supplemental survey, to evaluate EPA implemented the UCM program national occurrence data. Within each occurrence for boron. in two phases or rounds. The first round cross-section, the actual number of of UCM monitoring generally extended The NIRS database includes 36 systems and analytical records for each radionuclides and inorganic compounds from 1988 to 1992 and is referred to as contaminant varies. The support (IOCs), including boron. The NIRS UCM Round 1 monitoring. The second document, ‘‘The Analysis of Occurrence provides contaminant occurrence data round of UCM monitoring generally Data from the Unregulated Contaminant from 989 ground water CWSs covering extended from 1993 to 1997 and is Monitoring (UCM) Program and referred to as UCM Round 2 monitoring. National Inorganics and Radionuclides 49 States (all except Hawaii) and does UCM Round 1 monitored for 34 Survey (NIRS) in Support of Regulatory not include surface water systems. The volatile organic compounds (VOCs), Determinations for the Second Drinking survey focused on ground water including 1,3-dichloropropene and Water Contaminant Candidate List’’ systems, in part because IOCs tend to 1,1,2,2-tetrachloroethane (52 FR 25720 (USEPA, 2006c), provides a description occur more frequently and at higher (USEPA, 1987)). UCM Round 2 of how the national cross-sections for concentrations in ground water than in monitored for 13 synthetic organic the Round 1 and Round 2 data sets were surface water. Each of the 989 randomly compounds (SOCs), sulfate and the developed. selected CWSs was sampled at a single same 34 VOCs from UCM Round 1 EPA constructed the national cross- time between 1984 and 1986. monitoring (57 FR 31776 (USEPA, sections in a way that provides a EPA analyzed the NIRS data to 1992a)). balance and range of States with varying generate the following occurrence and The UCM Round 1 database contains pollution potential indicators, a wide exposure summary statistics for boron: contaminant occurrence data from 38 range of the geologic and hydrologic VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00010 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24025 (section III.B.2) and the results of the nationally consistent data describing waters sources used by CWSs. The AWWARF survey are presented in water quality in ground water and focused survey studied source waters section IV.B of this action. surface water. In 1991, USGS from 134 CWSs suspected or known to d. Presentation of Occurrence Data implemented the National Water- contain MTBE. The reports/results and and Analytical Approach. As noted Quality Assessment (NAWQA) Program data sets from the survey can be previously, the occurrence values and for 10-year cyclical data collection and accessed at http://sd.water.usgs.gov/ summary statistics presented in this data analyses. During the first cycle nawqa/vocns/nat—survey.html. The action are the actual data from the (1991–2001), the NAWQA program random survey results can be found in UCMR 1, UCM, and NIRS data sets. monitored 51 major watersheds and the USGS Water Resources These occurrence values represent aquifers (study units), which supply Investigations Report 02–4079, direct counts of the number and percent more than 60% of the nation’s drinking referenced as Grady (2003). The focused of systems, and population served by water and water used for agriculture and survey results can be found in the USGS systems, with at least 1 analytical industry in the U.S. (Hamilton et al., Water Resources Investigations Report detection above some specified 2004). NAWQA has collected data from 02–4084, referenced as Delzer and concentration threshold. EPA over 6,400 surface water and 7,000 Ivahnenko (2003a). considered this to be the most ground water sampling points. USGS b. USGS National Highway Runoff straightforward and accurate way to National Synthesis teams prepare Data and Methodology Synthesis. In present these data for the regulatory comprehensive analyses of data on addition to the NAWQA project, USGS determination process. topics of particular concern. EPA has prepared additional surveys of While both UCMR 1 and UCM data evaluated information/data from the national contaminant occurrence. For could support more involved statistical following USGS National Synthesis the National Highway Runoff Data and modeling to characterize occurrence reports/projects: Methodology Synthesis, USGS based on mean (rather than peak) (1) The NAWQA Pesticide National conducted a review of 44 studies of concentrations, EPA chose not to Synthesis Project. In 2003, USGS posted semi-volatile organic compounds perform this step for the regulatory the preliminary results from the first (SVOCs) and VOCs in runoff conducted determinations proposed in this action. cycle of monitoring for pesticides in since 1970. The USGS Synthesis sought EPA believes that presenting the actual streams and ground water. USGS to evaluate data quality parameters for results of the occurrence monitoring is considers these results to be provisional. comparison between and among these straight-forward and the use of an The results and the data can be accessed studies, including documentation of analysis based on peak concentrations at http://ca.water.usgs.gov/pnsp/. Data sampling protocols and methods, limits provides conservative estimates of are presented separately for surface of reporting and detection, and occurrence and potential exposure from water and ground water, as well as bed protocols of quality-control and quality- drinking water. Given that the sediments and biota. In each case, assurance. The complete USGS report is preliminary determinations for the 11 results are subdivided by land use Open-File Report 98–409 and is contaminants discussed in this action category. Land use categories include referenced as Lopes and Dionne (1998). are negative, it is not necessary to go agricultural, urban, mixed (deeper c. Toxics Release Inventory. EPA beyond the conservative (peak aquifers of regional extent in the case of established the Toxics Release Inventory concentration) approach used for this ground water), and undeveloped. In this (TRI) in 1987 in response to section 313 analysis. action, the NAWQA pesticide data for of the Emergency Planning and 2. Supplemental Data. The Agency surface water are referenced as Martin et Community Right-to-Know Act evaluated several sources of al. (2003) and the ground water data are (EPCRA). EPCRA section 313 requires supplemental occurrence information to referenced as Kolpin and Martin (2003). facilities to report to both EPA and the augment the primary drinking water (2) The National Survey of MTBE and States annual information on toxic occurrence data, to evaluate the Other VOCs in Community Drinking chemical releases from facilities that likelihood of contaminant occurrence, Water Sources (part of the VOC National meet reporting criteria. EPCRA section and/or to more fully characterize a Synthesis Project). In 2003, USGS 313 also requires EPA to make this contaminant’s presence in the published the survey findings for information available to the public environment. Sections II.B.2.a through MTBE, other ether gasoline oxygenates, through a computer database. This II.B.2.f provide brief descriptions of the and other volatile organic compounds database is accessible through TRI main supplemental information/data (VOCs) in source water used by CWSs Explorer, which can be accessed at sources cited in this action. in the United States. The survey was http://www.epa.gov/triexplorer. In 1990 Summarized occurrence findings from funded by AWWARF and performed by Congress passed the Pollution these supplemental sources are USGS in collaboration with the Prevention Act, which required that presented in Section IV.B, the Metropolitan Water District of Southern additional data on waste management contaminant profiles section. While the California and the Oregon Health and and source reduction activities be following descriptions cover the more Science University. USGS performed reported under TRI. The TRI database commonly referenced supplemental the survey in two independent stages details not only the types and quantities sources of information/data, they do not designed to provide representative of toxic chemicals released to the air, include every study and survey cited in sampling of all CWSs in the United water, and land by facilities, but also the contaminant discussions. A more States (Random Source-Water Survey) provides information on the quantities detailed discussion of the supplemental and to improve understanding of the of chemicals sent to other facilities for sources of information/data that EPA temporal variability of MTBE and other further management (USEPA, 2002b and evaluated for each contaminant can be compounds in selected water sources 2003b). found in the comprehensive regulatory (Focused Source-Water Survey). Facilities are required to report determination support document Participating water utilities provided releases and other waste management (USEPA, 2006a). samples that were analyzed for 66 activities related to TRI chemicals if a. USGS NAWQA Information/Data. VOCs. The random survey design they manufacture, process, or otherwise The United States Geological Survey selected 954 CWSs to be nationally use more than established threshold (USGS) collects long-term and representative of surface and ground quantities of these chemicals. Currently VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00011 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24026 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules for most chemicals, the thresholds are f. The AWWARF Boron Study. The NIRS data, how EPA assessed the data 25,000 pounds for manufacturing and American Water Works Research quality, completeness, and processing and 10,000 pounds for use. Foundation funded a survey to evaluate representativeness, and how the data Although TRI can provide a general idea the occurrence of boron (as well as were used to generate estimates of of release trends, it is far from hexavalent chromium) in drinking water contaminant occurrence. The ‘‘UCMR 1 exhaustive and should not be used to sources (Frey et al., 2004). The Occurrence Report’’ provides more estimate general public exposure to a AWWARF study recruited 189 PWSs detailed information about the UCMR 1 chemical (USEPA, 2002b and 2003b). representing 407 source waters in 41 data, how EPA assessed the data quality, d. Pesticides in Ground Water states. Of the 407 source water sample completeness, representativeness, and Database. The Pesticides in Ground kits distributed in 2003, approximately how the data were used to generate Water Database (PGWDB) is a 342 were returned. Of these 342 estimates of contaminant occurrence. compilation of data from ground water samples, 341 were analyzed for boron. The comprehensive regulatory studies conducted by Federal, State, and Approximately 67 percent (or 228) support document (USEPA, 2006a) local governments, the pesticide represented ground water sources and provides a summary of the results from industry, and other institutions between 33 percent (or 113) represented surface the drinking water occurrence analyses 1971 and 1991 (USEPA, 1992b). Data water sources. The results of the discussed in the aforementioned from 68,824 wells in 45 states are AWWARF survey for boron are technical support documents, as well as included. The vast majority of the wells presented in section IV.B of this action. information on production and use, (65,865) were drinking water wells. 3. Supporting Documentation for environmental releases, and/or Monitoring was conducted for 258 Occurrence. As mentioned in section occurrence in ambient water, potential pesticides and 45 degradates. Not all II.E, EPA prepared several technical health effects, the Agency’s preliminary studies tested for every compound. occurrence documents to support this determination, and the rationale for the e. The National Pesticide Survey. In action. These technical occurrence determination. 1990, EPA completed a national survey documents include the following: of pesticides in drinking water wells. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00012 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24027 BILLING CODE 6560–50–C high energy fuels (USGS, 2004; ATSDR, Academies categorizes boron as a B. Contaminant Profiles 1992). possible trace mineral nutrient for Natural processes such as the humans. Boron is essential for plant This section provides further details weathering of rocks, volcanic activity, growth and deficiency studies in on the background, health, and and geothermal steam contribute to the animals and humans have provided occurrence information that the Agency release of boron in the environment. some evidence that low intakes of boron used to evaluate each of the 11 Releases to the environment from affects cellular function and the activity candidate contaminants considered for human activities occur through the of other nutrients. It may interact with regulatory determination. For each production, use, and disposal of boron- Vitamin D and calcium homeostasis, candidate, the Agency evaluated the containing compounds (e.g., industrial influence estrogen metabolism, and play available human and toxicological data, emissions, fertilizer and herbicide a role in cognitive function (IOM, 2001). derived a health reference level, and runoff, hazardous waste deposits, and Iyengar et al. (1988) reported an average evaluated the potential and/or likely municipal sewage) (HSDB, 2004a; dietary intake of 1.5 mg/day for male occurrence and exposed population for ATSDR, 1992). adults based on the Food and Drug the contaminant in public water Although quantitative data are not Administration (FDA) Total Diet Study systems. The Agency used the findings available on the man-made releases of (TDS). from these evaluations to determine most borates in the United States, two Some human oral data are available whether the three SDWA statutory boron halide compounds, boron from cases where boron was ingested as requirements were satisfied. trichloride and boron trifluoride, are a medical treatment. When the amount As discussed in section II.E, the listed as Toxics Release Inventory (TRI) ingested was less than 3.68 mg/kg, Agency has also prepared a regulatory chemicals. TRI data for boron subjects were asymptomatic, while support document (USEPA, 2006a) that trichloride and boron trifluoride are doses of 20 and 25 mg/kg resulted in provides more details on the reported for the years 1995 to 2003 nausea and vomiting. Case reports and background, health, and occurrence (USEPA, 2006d). The TRI data show surveys of accidental poisonings information/analyses used to evaluate boron trichloride releases from facilities indicate that the lethal doses of boron and make preliminary determinations in 6 States and indicate that air range from 15 to 20 grams for these 11 candidates. emissions account for all of the total (approximately 200 to 300 mg/kg) for adults, 5 to 6 grams (approximately 70 1. Boron releases of boron trichloride (on- and off-site), which generally fluctuated in to 85 mg/kg) for children, and 2 to 3 a. Background. Boron, a metalloid, the range of hundreds of pounds per grams (approximately 30 to 45 mg/kg) tends to occur in nature in the form of year during the period of record. The for infants (USEPA, 2004b). borates (e.g., boric acid, borax, boron TRI data show boron trifluoride releases The primary adverse effects seen in oxide). Man-made releases are typically from facilities in 14 States and indicate animals after chronic exposure to low in the form of borates or boron halides that air emissions also account for doses of boron generally involve the (e.g., boron trichloride, boron nearly all of the boron trifluoride testes and developing fetus. Chronic trifluoride). Boron compounds are used releases, which ranged in the tens of effects of dietary boron exposure in two- in the production of glass, ceramics, thousands of pounds annually. year studies included testicular atrophy soaps, fire retardants, pesticides, b. Health Effects. The Institute of and spermatogenic arrest in dogs, cosmetics, photographic materials, and Medicine (IOM, 2001) of the National decreased food consumption, VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00013 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS EP01MY07.051 24028 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules suppressed growth, and testicular 1,400 [mu]g/L (the HRL for boron). The meaningful opportunity for health risk atrophy in rats, and decreased survival, NIRS data indicate that approximately reduction. testicular atrophy, and interstitial cell 4.3 percent (or 43) of the 989 ground The Agency encourages those States hyperplasia in mice. Although water PWSs sampled had detections of with public water systems that have researchers observed some increases in boron at levels greater than 700 [mu]g/ boron at concentrations above the HRL tumor incidences in the liver and in L, affecting approximately 2.9 percent of to evaluate site-specific protective subcutaneous tissues in mice, based on the population served (or 42,700 people measures and to consider whether State- comparisons to historic controls, these from 1.48 million). Approximately 1.7 level guidance (or some other type of tumors were determined not to be percent (or 17) of 989 ground water action) is appropriate. The Agency also associated with exposure to boron from PWSs sampled had detections of boron plans to update the Health Advisory for boric acid (USEPA, 2004b). Boron is not at levels greater than 1,400 [mu]g/L, boron to provide more recent health considered mutagenic and the Agency affecting approximately 0.4 percent of information. The updated Health determined that there are inadequate the population served (6,400 people Advisory will provide information to data to assess the human carcinogenic from 1.48 million) (USEPA, 2006a and any States with public water systems potential for boron (USEPA, 2004c). 2006c). that may have boron above the HRL. In developmental studies with rats, Because NIRS did not contain data for 2 and 3. Mono- and Di-Acid Degradates mice, and rabbits, oral exposure to boric surface water systems, the Agency of Dimethyl Tetrachloroterephthalate acid resulted in decreased pregnancy evaluated the results of a survey funded (DCPA) rate, increased prenatal mortality, by the American Water Works decreased fetal weights, and increased Association Research Foundation (Frey a. Background. Dimethyl malformations in fetuses and pups. et al., 2004) to gain a better tetrachloroterephthalate (DCPA), a However, these reproductive effects understanding of the potential synthetic organic compound (SOC) were associated with maternal toxicity occurrence of boron in surface water marketed under the trade name including changes in maternal organ systems. The AWWARF study recruited ‘‘Dacthal,’’ is a pre-emergent herbicide weights, body weights, weight gain, and 189 PWSs representing 407 source historically used to control weeds in increased renal tubular dilation and/or waters that covered 41 states. Of these ornamental turf and plants, regeneration (Price et al., 1990, 1994, 407 PWS source water samples, 342 strawberries, seeded and transplanted 1996; Heindel et al., 1992, 1994; Field were returned and 341 were analyzed vegetables, cotton, and field beans. As of et al., 1989). Reproductive effects in for boron. Of these 341 samples, 1990, more than 80 percent of its use males were noted in the subchronic and approximately 67 percent (or 228) was for turf, including golf courses and chronic studies described in the represented ground water sources and home lawns (USEPA, 1990b). On July preceding paragraphs. 33 percent (or 113) represented surface 27, 2005, in response to concerns about The EPA RfD for boron is 0.2 mg/kg/ water sources. None of the 113 surface groundwater contamination (especially day (USEPA, 2004c) based on water sources exceeded the boron HRL for one of the DCPA degradates), the developmental effects in rats from two of 1,400 [mu]g/L and the maximum Agency published a Federal Register studies (Price et al., 1996; Heindel et al., concentration observed in surface water notice announcing that the registrant for 1992). The RfD was derived using the was 345 [mu]g/L. Extrapolation of the Dacthal had voluntarily terminated a benchmark dose (BMD) method (bench data indicates that 95 percent of the number of uses for products containing mark dose level or BMDL from Allen et ground water detections had boron DCPA (70 FR 43408; USEPA, 2005f). al., 1996). EPA calculated the HRL of levels less than 1,054 [mu]g/L; the The only uses retained were those for 1.4 mg/L or 1,400 [mu]g/L for boron maximum observed concentration in use on sweet potatoes, eggplant, kale using the RfD of 0.2 mg/kg-day and a 20 ground water was approximately 3,300 and turnips. percent screening relative source [mu]g/L. Seven of the 228 ground water DCPA is not especially mobile or contribution. sources (from 5 systems) had boron persistent in the environment. EPA also evaluated whether health concentrations greater than 1,400 [mu]g/ Biodegradation and volatilization are information is available regarding the L (Seidel, 2006). the primary dissipation routes. potential effects on children and other d. Preliminary Determination. The Degradation of DCPA forms two sensitive populations. Studies in rats, Agency has made a preliminary breakdown products, the mono-acid mice, and rabbits identify the determination not to regulate boron degradate (or monomethyl developing fetus as potentially sensitive with an NPDWR. While boron was tetrachloroterephthalate or MTP) and to boron. Price et al. (1996) identified a found at levels greater than the HRL the di-acid degradate LOAEL of 13.3 mg/kg-day and an (and 1⁄2 the HRL) in several of the (tetrachloroterephthalic acid or TPA). NOAEL of 9.6 mg/kg-day in the ground water systems surveyed by The di-acid, which is the major developing fetus, based on decreased NIRS, it was not found at levels greater degradate, is unusually mobile and fetal body weight in rats. Accordingly, than the HRL (or 1⁄2 the HRL) in the persistent in the field, with a potential boron at concentrations greater than the surface waters sources evaluated in the to leach into water (USEPA, 1998c). HRL might have an effect on prenatal AWWARF study. Taking this surface Several studies and reports provide development. Individuals with severely water information into account, the estimates of the amount of DCPA used impaired kidney function might also be Agency believes that the overall during the 1990s in the United States. sensitive to boron exposure since the national occurrence and exposure from The Agency estimated that 1.6 million kidney is the most important route for both surface and ground water systems pounds of DCPA active ingredient a.i. excretion. together is likely to be lower than the were used annually in the early 1990s c. Occurrence Analyses. The National values observed for the NIRS ground (USEPA, 1998c). USGS estimated that Inorganics and Radionuclides Survey water data. Because boron is not likely approximately 998 thousand pounds of (NIRS) included boron as an analyte. to occur at levels of concern when DCPA a.i. were used annually circa Using data from NIRS, EPA performed considering both surface and ground 1992 (Thelin and Gianessi, 2000). The an initial evaluation of occurrence and waters systems, the Agency believes that National Center for Food and exposure at levels greater than 700 a national primary drinking water Agricultural Policy (NCFAP, 2004) [mu]g/L (1⁄2 the HRL) and greater than regulation does not present a estimates that approximately 1.7 million VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00014 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24029 pounds of DCPA a.i. were used in 1992 population for DCPA exposure. Results wells (using a detection limit of 0.06 and approximately 600 thousand of a single developmental study indicate [mu]g/L). While the di-acid degradate pounds a.i. were used in 1997 (NCFAP, that exposure to pregnant dams with was detected in 49 of 1,347 wells (using 2004). The NCFAP data suggest a doses less than or equal to 2,500 mg/kg/ a detection limit of 0.1 [mu]g/L), the decrease in the use of DCPA from the day of TPA via gavage did not have an maximum reported concentration of 7.2 early to the late 1990s. adverse effect on the fetus. EPA did not [mu]g/L did not exceed the HRL of 70 b. Health Effects. Currently, no identify any data that suggest gender- [mu]g/L (USEPA, 1990a). subchronic or chronic studies are related differences in toxicity or The USGS NAWQA program included available to assess the toxicological sensitivity in the elderly. the DCPA parent and the mono-acid effects of MTP (the mono-acid c. Occurrence. EPA included the degradate as analytes in its 1992–2001 degradate) and 3 studies in rats (30 and DCPA mono- and di-acid degradates monitoring survey of ambient surface 90-day feeding studies and a one- (MTP and TPA) as analytes in the and ground waters across the United generation reproductive study) are UCMR 1. The analysis results reported States. EPA evaluated the results of the available for TPA (the di-acid for UCMR 1 are the sum of both the provisional data, which are available on degradate). The effects of exposure were mono- and di-acid degradates. EPA the Web (Martin et al., 2003; Kolpin and mild (weight loss and diarrhea) and converted the analysis result for the Martin, 2003). While the USGS detected occurred at doses greater than or equal degradates to the parent DCPA the DCPA parent in both surface and to 2,000 mg/kg/day. No reproductive equivalent and performed an initial ground waters, at least 95 percent of the effects were observed. evaluation of occurrence and exposure samples from the various land use The present toxicity database for MTP at levels greater than 35 [mu]g/L (1⁄2 the settings were less than or equal to 0.007 and TPA is not sufficient to derive RfDs HRL) and greater than 70 [mu]g/L (the [mu]g/L. The estimated maximum for these two chemicals. However, since HRL). As previously discussed, EPA surface water concentration, 40 [mu]g/L the available data indicate that neither used the HRL derived for the DCPA (agricultural setting), and the estimated MTP nor TPA are more toxic than their parent because it includes the toxicity maximum ground water concentration, parent compound, DCPA, the Agency for the mono- and di-acid degradates. 10 [mu]g/L (agricultural setting), are suggests that the RfD for the DCPA While the UCMR 1 data indicate that the both less than 70 [mu]g/L (the DCPA parent would be protective against DCPA degradates were the most HRL). While the USGS detected the exposure from these two DCPA commonly reported analytes in the mono-acid degradate in both surface metabolites (USEPA, 1998c). Both monitoring survey (detected at an MRL waters and ground waters, at least 95 compounds are formed in the body from of 1 [mu]g/L in 772 samples from 175 percent of the samples from the various the DCPA parent and therefore, the of the 3,868 PWSs sampled), very few toxicity of these degradates is reflected land use settings were less than 0.07 systems exceeded the health level of [mu]g/L (the reporting limit for the in the toxicity of the parent. The RfD for concern. PWSs with detections were DCPA is 0.01 mg/kg/day based on a mono-acid degradate). The maximum found in 24 States and 1 Territory. The surface water concentration, 0.43 [mu]g/ chronic rat study (ISK Biotech UCMR 1 data indicate that Corporation, 1993) with a NOAEL of 1.0 L (agricultural setting), and the approximately 0.05 percent (or 2) of the maximum ground water concentration, mg/kg/day and an uncertainty factor of 3,868 PWSs sampled had a detection of 100 for rat to human extrapolation and 1.1 [mu]g/L (agricultural setting), are the DCPA degradates at levels greater both less than 70 [mu]g/L (the DCPA intra-species variability. than 35 [mu]g/L, affecting No carcinogenicity studies have been HRL, which includes the toxicity of the approximately 0.33 percent of the degradates). performed using either TPA or MTP. population served (or 739,000 people Based on the cancer data for the parent Beginning in 1992, the registrant for from 225 million). Approximately 0.03 DCPA performed two small-scale and lack of mutagenicity for TPA and percent (or 1) of the 3,868 PWSs DCPA, the Agency (USEPA, 2004d) ground water occurrence studies in New sampled have a detection of the DCPA York and California over a period of 17 concludes that TPA is unlikely to pose degradates at levels greater than 70 a cancer risk. Klopman et al. (1996) and 22 months, respectively. The [mu]g/L, affecting less than 0.01 percent registrant monitored for the DCPA evaluated the carcinogenic potential of of the population served (or 500 people TPA based on its chemical and parent and both of its degradates. The from 225 million) (USEPA, 2006a and average reported values, which are the biological properties, as well as by a 2006b). variety of computational tools, and sum of the parent and its degradates, EPA also evaluated several sources of were 50.36 [mu]g/L in New York and determined that it did not present any supplemental occurrence information substantial carcinogenic risk. There was 12.75 [mu]g/L in California. Neither for the DCPA parent, the mono-acid average value exceeded the HRL of 70 suggestive evidence that DCPA could be degradate and/or the di-acid degradate. carcinogenic based on an increased [mu]g/L (USEPA, 1998c). These supplemental sources include: d. Preliminary Determination. The incidence of thyroid and liver tumors in VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00015 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24030 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules The Agency encourages those States suggest a possible association of the of occurrence information. While the with public water systems that have levels of DDE in serum with breast USGS detected DDE in both surface and detects for these degradates to evaluate cancer. However, other studies with ground waters, 95 percent of the site-specific protective measures and to similar methodologies do not show any samples from the various land use consider whether State-level guidance association. DDE was mutagenic in settings were less than 0.006 [mu]g/L (or some other type of action) is mouse lymphoma L5178Y and Chinese (the USGS reporting limit). The appropriate. The Agency also plans to hamster V79 cells but negative in the maximum surface water concentration, update the Health Advisory for the Ames assay. In the 1988 IRIS, EPA 0.062 [mu]g/L (agricultural setting), and DCPA parent to include the mono and calculated an oral slope factor of 0.34 the maximum ground water di acid degradates, as well as any recent (mg/kg/day)-1 for DDE (USEPA, 1988a). concentration, 0.008 [mu]g/L health information related to these For this regulatory determination, EPA (agricultural setting), are both less than compounds. The updated Health calculated an oral slope factor from the 0.2 [mu]g/L (the DDE HRL). Advisory will provide information to same data set (from the 1988 IRIS) using d. Preliminary Determination. The any States with public water systems the EPA 1999 Cancer Guidelines Agency has made a preliminary that may have DCPA degradates at (USEPA, 1999a). The revised slope determination not to regulate DDE with levels above the HRL. factor is 1.67 x 10-1 (mg/kg/day)-1 an NPDWR. Because DDE appears to resulting in a one-in-a-million cancer- 4. 1,1-Dichloro-2,2-bis(p-chlorophenyl) occur infrequently at levels of concern risk (HRL) of 0.2 [mu]g/L. ethylene (DDE) in PWSs, the Agency believes that a There are some indications that DDE national primary drinking water a. Background. DDE is a primary has an adverse impact on the immune regulation does not present a 15 metabolite of DDT, a pesticide once system (Banerjee et al., 1996). Oral meaningful opportunity for health risk used to protect crops and eliminate exposures to 22 mg/kg/day for 6 weeks reduction. DDE was detected in only disease-carrying insects in the U.S. until suppressed serum immunoglobin levels one of the PWSs monitored under the it was banned in 1973. DDE itself has no and antibody titers. Inhibition of UCMR 1 at a level greater than the MRL commercial use and is only found in the leucocytes and macrophage migration (0.8 [mu]g/L), a concentration that is environment as a result of were observed at the cellular level. within the 10-4 to the 10-6 cancer risk contamination and/or breakdown of Considerable evidence exists that DDE range. In addition, ambient water data DDT. While DDE tends to adsorb can act as an endocrine disruptor since from the USGS indicate that the strongly to surface soil and is fairly it binds to the estrogen and androgen maximum concentrations detected in insoluble in water, it may enter surface receptors. DDE has a stronger affinity for surface and ground water were less than waters from runoff that contains soil the androgen receptor than for the the HRL of 0.2 [mu]g/L. particles contaminated with DDE. In estrogen receptor. It competes with EPA recognizes that DDE is listed as both soil and water, DDE is subject to testicular hormones for the androgen a probable human carcinogen. For this photodegradation, biodegradation, and receptor leading to receptor-related reason, the Agency encourages those volatilization (ATSDR, 2002). changes in gene expression (Kelce et al., States with public water systems that b. Health Effects. DDE is not produced 1995). might have DDE above the HRL to as a commercial product. This has EPA evaluated whether health evaluate site-specific protective limited the numbers of conventional information is available regarding the measures and to consider whether State- studies that have been performed to potential effects on children and other assess toxicological properties. Limited level guidance (or some other type of sensitive populations. Children and action) is appropriate. data on DDE, mostly from a National adolescents may be sensitive Cancer Institute (NCI) bioassay, suggest populations for exposure to DDE due to 5. 1,3-Dichloropropene (1,3-DCP; that the liver is the primary target organ its endocrine disruption properties. Telone) in mammalian species. However, the Some data suggest that DDE can delay a. Background. 1,3-Dichloropropene NCI study did not evaluate a full array puberty in males (ATSDR, 2002). (1,3-DCP), a synthetic volatile organic of noncancer endpoints. There is an RfD c. Occurrence. EPA included DDE as compound, is used as a pre-plant soil of 0.0005 mg/kg/day for the parent an analyte in the UCMR 1. Because the fumigant to control nematodes and HRL for DDE (0.2 [mu]g/L) is lower than pesticide DDT based on a NOAEL of other pests in soils to be planted with the minimum reporting limit (MRL) 0.05 mg/kg/day from a dietary all types of food and feed crops. 1,3-DCP used for monitoring (0.8 [mu]g/L), EPA subchronic study (USEPA, 1996b). In is typically injected 12’’ to 18’’ beneath used the MRL value to evaluate this study, liver lesions were identified the soil surface and can only be used by at a LOAEL of 0.25 mg/kg/day. Data on occurrence and exposure. The MRL is certified handlers (USEPA, 1998b). To DDT identify effects on the nervous and within the 10-4 to the 10-6 cancer risk mitigate risks to drinking water, 1999 hormonal systems as adverse effects that range for DDE. In evaluating the UCMR labeling requirements restrict the use of might also be seen with DDE because it 1 data, EPA found that approximately 1,3-DCP: is one of DDT’s primary metabolites. 0.03 percent (or 1) of the 3,867 PWSs VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00016 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24031 Estimates of national annual use Under the proposed cancer risk The UCM Round 2 Cross Section data during the 1990s vary widely, from assessment guidelines, the weight of indicate that approximately 0.30 percent approximately 23 to 40 million pounds evidence for evaluation of 1,3-DCP’s (or 50) of the 16,787 PWSs sampled had of active ingredient a.i. Based on ability to cause cancer suggest that it is detections of 1,3-DCP at levels greater information from a 1991 data call-in and likely to be carcinogenic to humans than 0.2 [mu]g/L (1⁄2 the HRL), affecting other sources, EPA estimates that (USEPA, 2000a). This characterization is approximately 0.42 percent of the approximately 23 million pounds of 1,3- supported by tumor observations in population served (or 193,000 of 46 DCP a.i. were used annually from 1990 chronic animal bioassays for both million). The UCM Round 2 Cross to 1995 (USEPA, 1998b). NCFAP (2004) inhalation and oral routes of exposure. Section data indicate that approximately estimates that approximately 40 million The oral cancer slope factors 0.23 percent (or 38) of the 16,787 PWSs pounds a.i. were used in 1992 and calculated from chronic dietary, gavage sampled had detections of 1,3-DCP at approximately 35 million pounds a.i. and inhalation data ranged from 5 x 10-2 levels greater than 0.4 [mu]g/L (the were used in 1997. to 1 x 10-1 (mg/kg/day)-1. Due to HRL), affecting approximately 0.33 1,3-Dichloropropene is listed as a TRI uncertainties in the delivered doses in percent of the population served (or chemical and releases are reported from some studies, EPA (IRIS) recommended 152,000 of 46 million). The 99th facilities in 17 States over a time period using the oral slope factor of 1 x 10-1 percentile of all detections is 39 [mu]g/ covering 1988 to 2003 (although not all (mg/kg/day)-1 from an NTP (1985) study. L and the maximum reported value is 39 States had facilities reporting releases Using this oral slope factor, EPA [mu]g/L. every year) (USEPA, 2006e). Air calculated an HRL of 0.4 [mu]g/L at the Because the sample preservative used emissions appear to account for most of 10-6 cancer risk level. may have resulted in potential the on-site (and total) releases and EPA also evaluated whether health underestimates of occurrence for the generally declined between 1988 and information is available regarding the UCM Rounds 1 and 2 data, EPA 2003. A sharp decrease in air emissions potential effects on children and other subsequently analyzed for 1,3-DCP is evident between 1995 and 1996. sensitive populations. No human or using the samples provided by 796 of Surface water discharges are minor animal studies are available that have the small systems included in the recent compared to air emissions and no examined the effect of 1,3-DCP exposure UCMR 1 survey. None of the 3,719 obvious trend is evident between 1988 on juvenile subjects. Therefore, its samples from these 796 small systems and 2003. Reported underground effects on children are unknown. (serving a population of 2.8 million) had injection, releases to land, and off-site Developmental studies in rats and detects of 1,3-DCP at levels greater than releases are generally insignificant. rabbits show no evidence of 0.5 [mu]g/L (the minimum reporting b. Health Effects. Chronic and developmental effects and therefore it is limit used for the analysis of 1,3-DCP subchronic exposures to 1,3-DCP at unlikely that 1,3-DCP causes and a level that is slightly higher than doses of 12.5 mg/kg/day and above in developmental toxicity. the HRL). animal dietary studies indicate that 1,3- c. Occurrence. EPA included 1,3-DCP EPA also evaluated several sources of DCP is toxic to organs involved in as an analyte in the UCM Round 1 and supplemental information, which metabolism (liver), excretion of UCM Round 2 surveys. The MRLs for included: conjugated metabolites (e.g., urinary UCM Round 1 ranged from 0.02 to 10 VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00017 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24032 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules concentrations greater than the HRL for levels of concern in subsequent more than 9 States having reporting 1,3-DCP, the overall percentage of monitoring surveys. facilities in any one year). Total positive wells detections was less than EPA recognizes that 1,3- reported releases for 2003 were 10,937 0.1 percent. dichloropropene is listed as a probable lbs. Trends for 2,6-DNT are similar to In 1998, the registrant for Telone (1,3- human carcinogen. For this reason, the those for 2,4-DNT. The TRI data for 2,6- DCP) submitted a private well water Agency encourages those States with DNT show a trend of declining releases study to the Agency. The well water public water systems that may have 1,3- in the late 1980s and early 1990s, and survey covered 5 regions where Telone dichloropropene above the HRL to a subsequent peak around 1999–2001. was used intensively and evaluated 518 evaluate site-specific protective On-site air emissions and surface water wells (5,800 samples) for the presence measures and to consider whether State- discharges are the most consistent types of 1,3-DCP. Of the 518 wells, 65 had level (or some other type of action) is of release for 2,6-DNT and surface water detectable levels of 1,3-DCP and/or its appropriate. The Agency also plans to discharges exhibit a declining trend metabolites at levels greater than 0.015 update the Health Advisory document (USEPA, 2006f). [mu]g/L (the detection limit for 1,3-DCP for 1,3-DCP to provide more recent In addition, TRI lists mixed DNT was 0.015 [mu]g/L and the metabolites health information. The updated Health isomer releases as a separate category were 0.023 [mu]g/L). None of the wells Advisory will provide information to over the same time period (1990–2003). exceeded 0.2 [mu]g/L (a level half the any States with public water systems TRI releases of mixed isomers were EPA-derived HRL for 1,3-DCP) (USEPA, that may have 1,3-DCP above the HRL. reported from facilities in 9 States, with 2004e and 2004f). 6 and 7. 2,4- and 2,6-Dinitrotoluenes no more than 7 States having reporting For the Random Source Water Survey, (2,4- and 2,6-DNT) facilities in any one year. Total releases the USGS collected samples from 954 a. Background. 2,4- and 2,6- in 2003 were 13,790 lbs. Underground source waters that supply community dinitrotoluene (DNT), semi-volatile injections made up the bulk of on-site water systems between 1999 and 2000. organic compounds, are two of 6 releases during the 1990s, but For the Focused Source Water Survey, isomers of dinitrotoluene. diminished thereafter. Air emissions the USGS collected 451 samples from Dinitrotoluenes are used in the remained relatively constant. Surface 134 source waters that supply production of polyurethane foams, water discharges and releases to land community water systems between 1999 automobile air bags, dyes, ammunition, were generally insignificant but peaked and 2001. The USGS included 1,3-DCP and explosives, including in 2003. Off-site releases varied widely. as an analyte in both surveys. The USGS trinitrotoluene or TNT (HSDB, 2004b Total releases peaked in 1993 and 1997, did not detect 1,3-DCP in any of the and 2004c; ATSDR, 1998). Neither 2,4- and generally diminished in recent source water samples from the Random nor 2,6-DNT occur naturally. They are years (USEPA, 2006f). Source Water Survey using a reporting generally produced as individual b. Health Effects. In experimental limit of 0.2 [mu]g/L (a level that is one- isomers or as a mixture called technical animal studies, 2,4- and 2,6-DNT appear half the HRL for 1,3-DCP). In addition, grade DNT (tg-DNT). Technical grade to be acutely toxic at moderate to high 17 the USGS did not detect 1,3-DCP in any DNT primarily contains a mixture of levels (LD50’s ranging from 180 to of the source water samples in the 2,4-DNT and 2,6-DNT with the 1,954 mg/kg) when administered orally. Focused Source Water Survey using a remainder consisting of the other In subacute studies (4 weeks) conducted detection limit of 0.024 [mu]g/L for cis- isomers and minor contaminants such by Lee et al. (1978), dogs, rats, and mice 1,3-dichloropropene and 0.026 [mu]g/L as TNT and mononitrotoluenes (HSDB, were fed 2,4-DNT and studied for toxic for trans-1,3-dichloropropene (levels 2004b). effects. A NOAEL of 5 mg/kg/day was that are about 16 times lower than the No recent quantitative estimates of established; decreased body weight gain HRL for 1,3-DCP) (Ivahnenko et al., DNT production or use are available. and food consumption, neurotoxic 2001; Grady, 2003; Delzer and The Hazardous Substances Data Bank signs, and lesions in the brain, kidneys, Ivahnenko, 2003a). (HSDB, 2004b) cites a 1980 EPA and testes occurred at 25 mg/kg/day (the d. Preliminary Determination. The Ambient Water Quality Criteria highest dose tested). Agency has made a preliminary Document that places combined 2,4- Subchronic studies in mice, rats, and determination not to regulate 1,3-DCP and 2,6-DNT production at 272,610,000 dogs that administered 2,4- and 2,6-DNT with an NPDWR. Because 1,3-DCP pounds in 1975. in the diet produced similar effects in appears to occur infrequently at health Both 2,4-DNT and 2,6-DNT are listed all species. All species exposed to 2,4- levels of concern in PWSs, the Agency as TRI chemicals. TRI data for 2,4-DNT DNT exhibited methemoglobinemia, believes that a national primary are reported from facilities in 21 States anemia, bile duct hyperplasia drinking water regulation does not over a time period covering 1988 to sometimes accompanied by hepatic present a meaningful opportunity for 2003. Total releases nationally in 2003 degeneration, and depressed health risk reduction. While 1,3-DCP were 14,899 lbs. Releases of all kinds spermatogenesis. Neurotoxicity and was detected in the UCM Round 1 (late (off-site releases and on-site air, surface, renal degeneration occurred in dogs at 1980s) and the UCM Round 2 (mid underground injection, and land a dose level of 20 mg/kg/day of 2,6-DNT 1990s) surveys, it was not detected in a releases) declined in the early 1990s, (Lee et al., 1976). At a dose level of 25 subsequent evaluation of 796 small and then peaked again around 1999– mg/kg/day of 2,4-DNT, male and female systems from the UCMR 1 survey. In 2001. On-site air emissions and surface dogs developed impaired muscle addition, the USGS did not detect 1,3- water releases of 2,4-DNT were movement and paralysis, DCP in two occurrence studies generally the most consistent (least methemoglobinemia, aspermatogenesis, performed between 1999 and 2001 using fluctuating) types of releases, with hemosiderosis of the spleen and liver, monitoring levels that were lower than surface water releases generally cloudy swelling of the kidneys, and the HRL. EPA believes the 1999 declining over the period on record lesions of the brain (Ellis et al., 1985). pesticide labeling requirements, which (USEPA, 2006f). are intended to mitigate risks to TRI data for 2,6-DNT are reported 17 LD50 = An estimate of a single dose that is drinking water, may be one reason for from facilities in 10 States over a time expected to cause the death of 50% of the exposed the lack of occurrence of 1,3-DCP at period covering 1988 to 2003 (with no animals. It is derived from experimental data. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00018 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24033 These doses were determined to be biliary tract hyperplasia, liver and for either 2,4- or 2,6-DNT using a LOAELs for these studies. kidney histopathology, and death in reporting limit of 5 [mu]g/L (a value 2,4-DNT has been shown to cause beagle dogs that were fed gelatin within the 10-4 to 10-6 risk range). reproductive effects in rats, mice, and capsules containing 2,6-DNT daily for d. Preliminary Determination. The dogs (Ellis et al., 1979; Lee et al., 1985; up to 13 weeks (Lee et al., 1976). The Agency has made a preliminary Hong et al., 1985; Ellis et al., 1985). Ellis NOAEL for this study was 4 mg/kg/day, determination not to regulate 2,4- or 2,6- et al. (1979) observed effects in rats and an uncertainty factor of 3,000 (100 DNT with an NPDWR. Because 2,4- and following dietary exposure after a dose for inter- and intra-species variability, 2,6-DNT appear to occur infrequently at of 35 mg/kg/day but not 5 mg/kg/day 10 for the use of a subchronic study, 3 levels of concern in PWSs, the Agency over 3 generations. Male mice fed 2,4- to account for the limited database) was believes that a national primary DNT for 13 weeks exhibited testicular applied to derive the RfD. drinking water regulation does not degeneration and atrophy and decreased DNT is likely to be carcinogenic to present a meaningful opportunity for spermatogenesis at 95 mg/kg/day (Hong humans (classified as a B2 carcinogen; health risk reduction. 2,4-DNT was et al., 1985). In another reproductive USEPA, 1990c). This is based on detected only once at a minimum study, dogs exhibited mild to severe significant increases in hepatocellular reporting level that is within the 10-4 to testicular degeneration and reduced carcinoma and mammary gland tumors the 10-6 cancer risk range, while 2,6- spermatogenesis (Ellis et al., 1985) in female rats fed DNT (98 percent 2,4- DNT was not detected at this same level when administered 2,4-DNT in capsules DNT with 2 percent 2,6-DNT) in the diet in any of the PWSs monitored under the at 25 mg/kg/day. There are currently no in a two-year study (Ellis et al., 1979). UCMR 1. studies of the reproductive or The tumor incidence in the female rats EPA recognizes that 2,4- and 2,6-DNT developmental toxicity of 2,6-DNT was used to establish a slope factor of are listed as probable human although a subchronic study in dogs 6.67 x 10-1 according to the 1999 EPA carcinogens. For this reason, the Agency identified atrophy of spermatogenic guidelines. Concentrations of 5 [mu]g/L, encourages those States with public cells in males suggesting a one- or two- 0.5 [mu]g/L, and 0.05 [mu]g/L are water systems that may have either 2,4- generation study as a data need for 2,6- associated with carcinogenic risks of or 2,6-DNT above the HRL to evaluate DNT. 10-4, 10-5, and 10-6 respectively. There site-specific protective measures and to Some studies evaluated the effects of were no studies found in the literature consider whether State-level guidance DNT in the form of a technical mixture that evaluated the effects of 2,4- or 2,6- (or some other type of action) is (tg-DNT). In a study by Price et al. DNT on children. There is evidence that appropriate. The Agency’s original (1985), the teratogenic potential of tg- the pups and fetuses from dams Health Advisories for 2,4- and 2,6-DNT DNT (containing approximately 76 administered tg-DNT had significant were developed for military percent 2,4-DNT and 19 percent 2,6- increases in relative liver and spleen installations. Because the Agency DNT) was investigated in rats. The weights (Price et al., 1985). DNT toxicity recognizes that 2,4- and 2,6-DNT may study was conducted in two phases to may be different in children, compared still be found at some military sites, the evaluate the possible teratogenicity of to adults, since it undergoes Agency has updated the Health DNT as well as DNT effects on postnatal bioactivation in the liver and by the Advisories to reflect recent health development. For the first phase, rats intestinal microflora (ATSDR, 1998). effects publications. The Health were administered 0, 14, 35, 37.5, 75, Newborns may be more sensitive to Advisories are available for review in 100, or 150 mg/kg/day of DNT in corn DNT-related methemoglobinemia the docket. The updated Health oil by gavage. In the postnatal phase, because an enzyme that protects against Advisories will provide information to rats were administered 14, 35, 37.5, 75, increased levels of methemoglobin is any States with public water systems or 100 mg/kg/day of DNT in corn oil by inactive for a short duration that may have either 2,4- or 2,6-DNT gavage. The NOAEL and LOAEL for immediately after birth (Gruener 1976; above the HRL. developmental toxicity were 14 and 35 ATSDR, 1998). However, there are no 8. s-Ethyl dipropylthiocarbamate (EPTC) mg/kg/day, respectively, based on experimental data on differences in significant increases in relative liver and children’s responses to 2,4-/2,6-DNT. a. Background. EPTC, a synthetic spleen weight in the fetuses of dams c. Occurrence. EPA included both 2,4- organic compound, is a thiocarbamate administered DNT at levels of 35 mg/kg/ and 2,6-DNT as analytes in the UCMR herbicide used to control weed growth day or greater. No teratogenic toxicity 1. Because the HRL for both 2,4- and during the pre-emergence and early was seen in the study rats. 2,6-DNT (0.05 [mu]g/L) is lower than post-emergence stages of weed In chronic exposures, oral dietary the minimum reporting limit used for germination. First registered for use in administration of 2,4-DNT to dogs monitoring (MRL of 2 [mu]g/L), EPA 1958, EPTC is used across the U.S. in primarily affected the nervous system, used the MRL to evaluate occurrence the agricultural production of a number erythrocytes, and biliary tract (Ellis et and exposure. The MRL is within the of crops, most notably corn, potatoes, al., 1979, 1985). Based on neurotoxicity, 10-4 to the 10-6 cancer risk range for dried beans, alfalfa, and snap beans. hematologic changes, and effects on the either 2,4- or 2,6-DNT. In evaluating the EPTC is also used residentially on shade bile ducts in dogs, the LOAEL was UCMR 1 data, EPA found that 1 of the trees, annual and perennial determined to be 1.5 mg/kg/day and the 3,866 PWSs sampled (or 0.03 percent) ornamentals, and evergreens (USEPA, NOAEL was 0.2 mg/kg/day. EPA detected 2,4-DNT at the MRL of 2 1999c). established an RfD of 0.002 mg/kg/day [mu]g/L, affecting 0.02 percent of the Estimates of EPTC usage in the United for 2,4-DNT (USEPA, 1992c) based on population served (or 38,000 people States suggest a decline from this study. An uncertainty factor of 100, from 226 million). None of the 3,866 approximately 17 to 21 million pounds to account for interspecies and PWSs sampled (serving 226 million) active ingredient in 1987 to intraspecies variability, was applied to detected 2,6-DNT at the MRL of 2 approximately 7 to 9 million pounds derive the RfD. [mu]g/L (USEPA, 2006a and 2006b). active ingredient in 1999. TRI data from EPA established an RfD of 0.001 mg/ EPA also evaluated the results of a 1995 to 2003 indicate that most on-site kg/day for 2,6-DNT (USEPA, 1992c). USGS review of 3 highway and urban industrial releases of EPTC tend to be This RfD was also based on runoff studies (Lopes and Dionne, releases to air and underground neurotoxicity, Heinz body formation, 1998). These studies showed no detects injections. Surface water discharges are VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00019 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24034 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules minimal in comparison (USEPA, 2006g). calculated to be 0.175 mg/L or 175 States. Both contaminated wells were in Total releases for 2003 were 2,183 lbs. [mu]g/L. Minnesota. The detected concentrations Environmental fate data indicate that The Agency used long-term studies in ranged from 0.01 to 0.33 [mu]g/L. All of EPTC would not be persistent under mice and rats and short-term studies of these positive detections are less than most environmental conditions. mutagenicity to evaluate the potential the HRL of 175 [mu]g/L, as well as 87.5 Volatilization into the atmosphere and for carcinogenicity (USEPA, 1990d). [mu]g/L (1⁄2 the HRL). degradation by soil organisms appear to Based on these data and using EPA’s The USGS NAWQA program included be the primary dissipation routes. EPTC 1999 Guidelines for Carcinogen Risk EPTC as an analyte in its 1992–2001 has a low affinity for binding to the soil Assessment, EPTC is not likely to be monitoring survey of ambient surface so the potential to leach to ground water carcinogenic to humans (USEPA, and ground waters across the United does exist. If EPTC reaches ground 1999a). States. EPA evaluated the results of the water, volatilization is less likely to EPA also evaluated whether health provisional data, which are available on occur (USEPA, 1999c). information is available regarding the the Web (Martin et al., 2003; Kolpin and b. Health Effects. In acute animal potential effects on children and other Martin, 2003). While the USGS detected toxicity studies, EPTC was shown to be sensitive populations. Data do not EPTC in both surface and ground moderately toxic via oral and dermal suggest increased pre- or post-natal waters, 95 percent of the samples from routes and highly toxic via inhalation sensitivity of children and infants to the various land use settings were less exposures. EPTC is a reversible EPTC exposure. In animal studies, than or equal to 0.018 [mu]g/L. The cholinesterase (ChE) inhibitor. Similar adverse developmental effects (i.e., estimated maximum surface water to other thiocarbamates, it does not decreased fetal body weight and concentration, 29.6 [mu]g/L (mixed land produce a consistent ChE inhibition decreased litter size) were only seen at use settings), and the maximum ground profile. There was no consistent pattern doses that were toxic to the mother water concentration, 0.45 [mu]g/L observed in any of the toxicity studies (USEPA, 1999c). Results from both (agricultural settings), are both less than with regard to species, duration of developmental and reproductive studies 175 [mu]g/L (the EPTC HRL). treatment, or the type of ChE enzyme indicate that there are only minimal d. Preliminary Determination. The measured. Typically, studies showed adverse effects. The behavior patterns of Agency has made a preliminary inhibition of plasma ChE with dose- children that lead to heightened determination not to regulate EPTC with related decreases in red blood cell and opportunities for exposure in the indoor an NPDWR. Because EPTC does not brain ChE activity. Some studies have environment and the need for a appear to occur at health levels of shown that brain ChE activity was developmental neurotoxicity study lead concern in PWSs, the Agency believes inhibited without any effect on either OPP to recommend the application of a that a national primary drinking water plasma or erythrocyte ChE activities. ten-fold FQPA factor for EPTC. regulation does not present a Other studies illustrated erythrocyte However, EPA did not apply this factor meaningful opportunity for health risk ChE inhibition with no effect on either in the screening analysis because it does reduction. While EPTC has been found plasma or brain ChE (USEPA, 1999c). In not apply to programs other than the in ambient waters, it was detected only a primary eye irritation study in rabbits, pesticide registrations. at levels less than the HRL (as well as c. Occurrence. EPA included EPTC as technical grade EPTC was shown to be 1⁄2 the HRL) and it was not found in the slightly irritating (USEPA, 1999c). an analyte in the UCMR 1. None of the UCMR 1 survey of public water In subchronic and chronic studies 3,866 PWSs sampled (serving a supplies. performed in both rats and dogs, there population of 226 million) had detects was a dose-related increase in the of EPTC at the MRL of 1 [mu]g/L. 9. Fonofos incidence and severity of Hence, these data indicate that no a. Background. Fonofos, an cardiomyopathy, a disorder of the heart occurrence and exposure is expected at organophosphate, is a soil insecticide 1 muscle (Mackenzie, 1986; USEPA, levels greater than 87.5 [mu]g/L ( ⁄2 the used to control pests such as corn 1999c). An increase in the incidence HRL) and greater than 175 [mu]g/L (the rootworms, cutworms, symphylans (i.e., and severity of degenerative effects HRL) (USEPA, 2006a and 2006b). garden centipedes), and wireworms. (neuronal and/or necrotic degeneration) EPA also evaluated several sources of Primarily used on corn crops, fonofos in both the central and peripheral supplemental information, which was also used on other crops such as included: asparagus, beans, beets, corn, onions, nervous system was observed in rats VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00020 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24035 approximately 3.2 million pounds of sensitive populations. In the available with an NPDWR. Because fonofos does fonofos a.i. were applied annually developmental studies with rabbits not appear to occur at health levels of around 1992 and approximately 0.4 (Sauerhoff, 1987) and mice (Minor et al., concern in PWSs, the Agency believes million pounds a.i. were applied 1982; Pulsford, 1991), no developmental that a national primary drinking water annually around 1997. The U.S. effects were observed at oral doses as regulation does not present a Geological Survey (USGS) estimates an high as 1.5 mg/kg/day in the rabbit meaningful opportunity for health risk average of 2.7 million pounds a.i. were (highest dose tested) nor in mice at reduction. While fonofos has been used annually around 1992 (Thelin and doses as high as 2.0 mg/kg/day (Minor found in ambient waters, it was detected Gianessi, 2000). et al., 1982; Pulsford, 1991). However, only at levels less than the HRL (as well Fonofos is moderately persistent in in mice, effects were noted at higher as 1⁄2 the HRL) and it was not found in soil and its persistence depends on soil dose levels. These effects included an UCMR 1 Screening Survey of public type, organic matter, rainfall, and increase in the incidence of variant water supplies. Fonofos was voluntarily sunlight. Since fonofos adsorbs sternebrae ossifications (at 6 mg/kg/day cancelled in 1998 and the Agency moderately well to soil, it is not readily or greater) and a slight dilation of the expects any remaining stocks and leached or transported to ground water fourth brain ventricle in offspring (at 4 releases into the environment to but it can be transported to surface mg/kg/day or greater). No decline. In addition, since fonofos tends waters in runoff. Fonofos is rapidly developmental neurotoxicity study with to bind strongly to soil, any releases to degraded by soil microorganisms fonofos is available for further the environment are not likely to (Extoxnet, 1993). Fonofos tends to assessment of this endpoint. In a three- contaminant source waters. volatilize from wet soil and water generation reproduction study in rats surfaces, but the process is slowed by (Woodard et al., 1968), no treatment- 10. Terbacil adsorption to organic material in soil, related adverse effects were observed at a. Background. Terbacil, a synthetic suspended solids, and sediment (HSDB, the 2 dose levels used in this study, 0.5 organic compound, is a selective 2004d). and 1.58 mg/kg/day. herbicide used to control broadleaf b. Health Effects. Fonofos (like many The Agency believes that the current weeds and grasses on terrestrial food/ organophosphates) is toxic to humans RfD is adequately protective of children. feed crops (e.g., apples, mint, and animals. Case reports and acute oral The current fonofos RfD of 0.002 mg/kg/ peppermint, spearmint, and sugarcane), toxicity studies in animals indicate that day is 1000-fold lower than the NOAEL terrestrial food (e.g., asparagus, oral exposure to fonofos induces clinical observed in the Woodard et al. (1968) blackberry, boysenberry, dewberry, signs of toxicity that are typical of developmental studies. loganberry, peach, raspberry, cholinesterase inhibitors. In humans, Using the RfD of 0.002 mg/kg/day for youngberry, and strawberry), terrestrial accidental exposures produced fonofos and a 20 percent screening feed (e.g., alfalfa, forage, and hay) and symptoms of acute intoxication, nausea, relative source contribution, the Agency forest trees (e.g., cottonwood) (USEPA, vomiting, salivation, sweating, muscle derived an HRL of 0.014 mg/L and 1998e). twitches, decreased blood pressure and rounded to 0.01 mg/L (or 10 [mu]g/L). In 1998, EPA estimated that pulse rate, pinpoint pupils, profuse c. Occurrence. EPA included fonofos agricultural usage of terbacil consumed salivary and bronchial secretions, as an analyte in the UCMR 1 List 2 cardiorespiratory arrest, and even death Screening Survey. None of the 2,306 approximately 221,000 to 447,000 in 1 exposed individual (Hayes, 1982; samples from the 295 PWSs sampled pounds of active ingredient annually Pena Gonzalez et al., 1996). (serving a population of 41 million) and non-agricultural usage consumed In animals, clinical signs of exposure contained detects for fonofos at the MRL approximately 9,000 to 14,000 pounds. included tremors, salivation, diarrhea, of 0.5 [mu]g/L. Hence, these data These estimates are based on data and labored breathing (USEPA, 1996c). indicate that no occurrence and collected mostly between 1990 and Chronic exposure studies also indicated exposure is expected at levels greater 1995, and in some cases as early as 1987 that oral administration of fonofos than 5 [mu]g/L (1⁄2 the HRL) and greater (USEPA, 1998e). According to NCFAP inhibits cholinesterase (Banerjee et al., than 10 [mu]g/L (the HRL) (USEPA, (2004), approximately 298,000 pounds 1968; Cockrell et al., 1966; Hodge, 1995; 2006a and 2006b). of terbacil a.i. were applied annually in Horner, 1993; Miller, 1987; Miller et al., The USGS NAWQA program included agriculture around 1992 and 1979; Pavkov and Taylor, 1988; fonofos as an analyte in its 1992–2001 approximately 342,000 pounds a.i. were Woodard et al., 1969). Cholinesterase monitoring survey of ambient surface applied around 1997. inhibition is one of the critical effects and ground waters across the United Terbacil is listed as a TRI chemical associated with the RfD, which was States. EPA evaluated the results of the and data are reported from one or more verified by EPA (USEPA, 1991) at 0.002 provisional data, which are available on facilities in a single state, Texas, for the mg/kg/day. EPA derived the RfD of the Web (Martin et al., 2003; Kolpin and time period covering 1995 to 1997. 0.002 mg/kg/day using a NOAEL of 0.2 Martin, 2003). While the USGS detected During this three-year period, all mg/kg/day (Hodge, 1995) and a 100-fold fonofos in both surface and ground reported releases were on-site releases uncertainty factor to account for inter- waters, 95 percent of the samples from to surface water that varied between and intraspecies differences. the various land use settings were less 3,000 to 10,000 pounds annually Fonofos is classified as an unlikely than 0.003 [mu]g/L (the reporting limit). (USEPA, 2006h). human carcinogen (Group E) because The maximum surface water Terbacil is considered a persistent there is no evidence of carcinogenic concentration, 1.20 [mu]g/L and potentially mobile herbicide in potential in the available long-term (agricultural setting), and the maximum terrestrial environments. Because of its feeding studies in rats and mice ground water concentration, 0.009 low affinity to soils, it can potentially (Banerjee et al., 1968; Pavkov and [mu]g/L (agricultural setting), are both leach into ground and/or surface waters Taylor, 1988; Sprague and Zwicker, less than 10 [mu]g/L and less than 5 (USEPA, 1998e; Extoxnet, 1994). 1987). In addition, fonofos does not [mu]g/L (the fonofos HRL and 1⁄2 the b. Health Effects. In acute and appear to be mutagenic (USEPA, 1996c). HRL). subchronic toxicity studies, terbacil is EPA evaluated whether health d. Preliminary Determination. The practically non-toxic (Haskell information is available regarding the Agency has made a preliminary Laboratories, 1965a and 1965b). Terbacil potential effects on children and other determination not to regulate fonofos does not cause dermal sensitivity in VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00021 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24036 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules rabbits or guinea pigs and causes mild weight ratios, slight increases in liver provisional data, which are available on conjunctival eye irritation in rabbits weights, and elevated alkaline the Web (Martin et al., 2003; Kolpin and (Henry, 1986; Hood, 1966). In rats phosphatase levels with a NOAEL of Martin, 2003). While the USGS detected exposed subchronically to dietary 1.25 mg/kg/day. In deriving the RfD, the terbacil in both surface and ground terbacil, effects were seen at a LOAEL of Agency applied an uncertainty factor of waters, 95 percent of the samples from 25 mg/kg/day and included increased 100 to account for interspecies and the various land use settings were less absolute and relative liver weights, intraspecies differences. Using the RfD than 0.034 [mu]g/L (the USGS reporting vacuolization, and enlargement of liver of 0.013 mg/kg/day and applying a 20 limit). The maximum surface water cells (Wazeter et al.,1964; Haskell percent screening relative source concentration, 0.54 [mu]g/L Laboratories, 1965c). contribution, the Agency derived an (agricultural setting), and the maximum A primary target organ in rats HRL of 0.090 mg/L (or 90 g/L) for ground water concentration, 0.891 following exposure to terbacil is the terbacil. [mu]g/L (mixed land use setting), are liver. Chronic effects of dietary terbacil EPA also evaluated whether health both less than 90 [mu]g/L and less than exposure in two-year studies included information is available regarding the 45 [mu]g/L (the terbacil HRL and 1⁄2 the increases in thyroid-to-body weight potential effects on children and other HRL). ratios, slight increases in liver weights sensitive populations. In the case of d. Preliminary Determination. The and elevated alkaline phosphatase terbacil, the Agency determined that Agency has made a preliminary levels in beagle dogs, significant there was no need to apply an FQPA determination not to regulate terbacil decreases in body weight in rats, factor to the RfD in order to protect with an NPDWR. Because terbacil does increases in serum cholesterol levels children (USEPA, 1998e). Other not appear to occur at health levels of and increases in liver to body weight potentially sensitive subpopulations concern in PWSs, the Agency believes ratios in rats (Wazeter et al.,1967a; have not been identified. that a national primary drinking water Malek, 1993). In beagle dogs, effects c. Occurrence. EPA included terbacil regulation does not present a were seen at or above 6.25 mg/kg/day as an analyte in UCMR 1. None of the meaningful opportunity for health risk (NOAEL = 1.25 mg/kg/day). In rats, 3,866 PWSs sampled (serving a reduction. Terbacil has been found in effects (i.e., decreases in body weight, population of 226 million) had detects ambient waters but the levels were less increases in liver weights and for terbacil at the MRL of 2 g/L. Hence, than the HRL (as well as 1⁄2 the HRL). cholesterol levels) were seen at higher these data indicate that no occurrence It was not found in the UCMR 1 survey levels (LOAELs = 56 mg/kg/day for and exposure is expected at levels of public water supplies. males and 83 mg/kg/day for females). greater than 45 g/L (1⁄2 the HRL) and Terbacil is not considered to be a greater than 90 [mu]g/L (the terbacil 11. 1,1,2,2-Tetrachloroethane developmental or reproductive toxicant. HRL) (USEPA, 2006a and 2006b). a. Background. 1,1,2,2- In developmental studies, maternal EPA also evaluated several sources of Tetrachloroethane, a volatile organic effects were generally seen prior to or at supplemental information, which compound, is not known to occur the same levels as developmental included: naturally in the environment (IARC, effects. Haskell Laboratories (1980) ≤ VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00022 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24037 Volatilization from water or soil methodology and examined a small at levels greater than 0.20 [mu]g/L (1⁄2 surfaces to the atmosphere appears to be number of rats (5 females and 7 males) the HRL), affecting approximately 1.69 the primary dissipation route for 1,1,2,2- exposed via inhalation to 1 dose (13.3 percent of the population served (or 1.6 tetrachloroethane. In subsurface soils mg/m3). There were no statistically million of 95 million). The UCM Round and ground water, 1,1,2,2- significant differences in the percentage 1 Cross Section data indicate that tetrachloroethane is subject to of females having offspring, number of approximately 0.20 percent (or 41) of biodegradation by soil organisms and/or pups per litter, average birth weight, sex the 20,407 PWSs sampled had chemical hydrolysis by water (ATSDR, ratio, or post natal offspring mortality detections of 1,1,2,2-tetrachloroethane 1996). (Schmidt et al., 1972). Effects on sperm at levels greater than 0.4 [mu]g/L (the b. Health Effects. Data on the toxicity in male rats were seen after oral (27 mg/ HRL), affecting approximately 1.63 of 1,1,2,2-tetrachloroethane in humans kg/day; NTP, 2004) and inhalation (13 percent of the population served (or 1.5 are limited, consisting of one mg/m3; Schmidt et al., 1972) exposures. million of 95 million). The 99th experimental inhalation study, a few Similar effects were seen in mice but at percentile of all detects is 112 [mu]g/L case reports of suicidal or accidental higher doses. Fetal toxicity did not and the maximum reported value is 200 ingestion, and dated occupational occur in the absence of maternal [mu]g/L. studies. In most cases, there was no toxicity. Analysis of the UCM Round 2 Cross quantification of the exposure. Developmental range-finding studies Section data indicate that approximately Respiratory and mucosal effects, eye conducted for NTP (1991a and b) found 0.07 percent (or 18) of the 24,800 PWSs irritation, nausea, vomiting, and that 1,1,2,2-tetrachloroethane was toxic sampled had detections of 1,1,2,2- dizziness were reported by human to the dams and pups of Sprague tetrachloroethane at levels greater than volunteers exposed to 1,1,2,2- Dawley rats and CD–1 Swiss mice. Rats 0.2 [mu]g/L (1⁄2 the HRL), affecting tetrachloroethane vapors under were more sensitive than mice. The approximately 0.51 percent of the controlled chamber conditions NOAEL in the rats for both maternal population served (or 362,000 of 71 (Lehmann and Schmidt-Kehl, 1936). toxicity and associated fetal toxicity was million). The UCM Round 2 Cross Effects from non-lethal occupational 34 mg/kg/day with a LOAEL of 98 mg/ Section data indicate that approximately exposures included gastric distress (i.e., kg/day. In mice, the NOAEL was 987 the same percentage and number of the pain, nausea, vomiting), headache, loss mg/kg/day and the LOAEL was 2,120 PWSs sampled (0.07 percent or 17 of the of appetite, an enlarged liver, and mg/kg/day. 24,800) had detections of 1,1,2,2- cirrhosis (Jeney et al., 1957; Lobo- EPA also evaluated whether health tetrachloroethane at levels greater than Mendonca, 1963; Minot and Smith, information is available regarding the 0.4 [mu]g/L (the HRL), affecting 1921). potential effects on children and other approximately 0.08 percent of the There have been a variety of animal sensitive populations. Individuals with population served (or 56,000 of 71 studies in rats and mice using both the preexisting liver and kidney damage million). The 99th percentile of all inhalation and oral exposure routes. would likely be sensitive to 1,1,2,2- detects is 2 [mu]g/L and the maximum Recent studies by the National tetrachloroethane exposure. Low intake reported value is 2 [mu]g/L. Toxicology Program (NTP, 2004) of antioxidant nutrients (e.g., Vitamin E, EPA also evaluated several sources of provide a detailed evaluation of the Vitamin C, and selenium) could be a supplemental information, which short-term and subchronic oral toxicity predisposing factor for liver damage. In included the USGS VOC National of 1,1,2,2-tetrachloroethane and confirm addition, individuals with a genetically Synthesis Random Source Water Survey many of the observations from earlier low capacity to metabolize and the Focused Source Water Survey. studies. In rats and mice exposed orally, dichloroacetic acid (the primary For the Random Source Water Survey, the liver appears to be the primary target metabolite of 1,1,2,2-tetrachloroethane) the USGS collected samples from 954 organ. The RfD (10 [mu]g/kg/day) for may be at greater risk than the general source waters that supply community 1,1,2,2-tetrachloroethane was derived population as a result of 1,1,2,2- water systems between 1999 and 2000. from the BMDL for a 1 standard tetrachloroethane exposure. For the Focused Source Water Survey, deviation change in relative liver c. Occurrence. EPA included 1,1,2,2- the USGS collected 451 samples from weight, a biomarker for liver toxicity. A tetrachloroethane as an analyte in the 134 source waters that supply 1,000-fold uncertainty factor was UCM Round 1 and UCM Round 2 community water systems between 1999 applied in the RfD determination. surveys. EPA evaluated the UCM Round and 2001. The USGS included 1,1,2,2- A National Cancer Institute (1978) 1 Cross Section and the UCM Round 2 tetrachloroethane as an analyte in both bioassay of 1,1,2,2-tetrachloroethane Cross Section data at levels greater than surveys and did not detect it in any of found clear evidence of carcinogenicity 0.2 [mu]g/L (1⁄2 the HRL) and greater the source water samples using a in male and female B6C3F1 mice based than 0.4 [mu]g/L (the HRL) (USEPA, reporting limit of 0.2 [mu]g/L (a level on a dose-related statistically significant 2006a and 2006c). The MRLs for UCM that is less than the 1,1,2,2- increase in liver tumors. There was Round 1 ranged from 0.1 to 10 [mu]g/ tetrachloroethane HRL). In addition, equivocal evidence for carcinogenicity L and the MRLs for UCM Round 2 USGS did not detect 1,1,2,2- in Osborn Mendel rats because of the ranged from 0.1 to 2.5 [mu]g/L. Because tetrachloroethane when using a occurrence of a small number of rare- some of the reporting limits exceeded detection level of 0.026 [mu]g/L (a level for-the species neoplastic and the thresholds of interest, the that is over 10 times lower than the preneoplastic lesions in the livers of the occurrence analyses may result in an 1,1,2,2-tetrachloroethane HRL) in the high dose animals. The Agency used the underestimate of systems affected. focused survey (Ivahnenko et al., 2001, slope factor of 8.5 x 10-2 for the tumors However, all the MRL values used for Grady, 2003, Delzer and Ivahnenko, in female mice to derive the HRL of 0.4 UCM Round 1 and UCM Round 2 are 2003a). [mu]g/L for use in the analysis of the within the 10-4 to the 10-6 cancer risk d. Preliminary Determination. The occurrence data for 1,1,2,2- range. Agency has made a preliminary tetrachloroethane. Information on the Analysis of UCM Round 1 Cross determination not to regulate 1,1,2,2- reproductive effects of 1,1,2,2- Section data indicates that tetrachloroethane with an NPDWR. tetrachloroethane is limited. There is a approximately 0.22 percent (or 44) of Because 1,1,2,2-tetrachloroethane single one-generation inhalation study the 20,407 PWSs sampled had appears to occur infrequently at health that does not follow a standard detections of 1,1,2,2-tetrachloroethane levels of concern in PWSs, the Agency VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00023 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24038 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules believes that a national primary 18 in order to determine whether surface and subsurface aqueous drinking water regulation does not regulating perchlorate would present a environments. Although commonly present a meaningful opportunity for meaningful opportunity for health risk known as a man-made chemical, health risk reduction. While 1,1,2,2- reduction. However, the Agency is perchlorate also may be derived from tetrachloroethane was detected in both considering several other approaches, natural processes. the UCM Round 1 and the UCM Round discussed below, for making this While perchlorate has a wide variety 2 surveys, the percentage of detections statutory determination and is of industrial uses, it is primarily used in had decreased by the time the UCM requesting public comment on the the form of ammonium perchlorate as Round 2 survey was performed in the strengths and limitations of these an oxidizer in solid fuels used to power mid-1990’s. In addition, the USGS did approaches. rockets, missiles, and fireworks. not detect 1,1,2,2-tetrachloroethane in The following sections explain why Approximately 90 percent of two subsequent monitoring surveys of EPA is not making a preliminary perchlorate is manufactured for this source waters that supply community regulatory determination for perchlorate application (Wang et al., 2002). water systems using a reporting limit at this time, and discusses the Perchlorate can also be present as an that is less than the 1,1,2,2- information the Agency has collected to ingredient or as an impurity in road tetrachloroethane HRL. The Agency date (that may be relevant to making a flares, lubricating oils, matches, believes that this decrease in detections preliminary regulatory determination), aluminum refining, rubber occurred because commercial the additional information the Agency is manufacturing, paint and enamel production of 1,1,2,2-tetrachloroethane soliciting in this action, and options for manufacturing, leather tanning, paper ceased in the mid-1980’s. Hence, the additional analyses that the Agency may and pulp processing (as an ingredient in Agency does not expect 1,1,2,2- conduct to support a regulatory bleaching powder), and as a dye tetrachloroethane to occur in many determination. Sections V.A through mordant. public water systems today. V.D provide a summary of the available Perchlorate can also occur naturally EPA recognizes that 1,1,2,2- and relevant information/data that the in the environment. Chile possesses tetrachloroethane is listed as a likely Agency has collected and reviewed caliche ores rich in sodium nitrate human carcinogen. For this reason, the regarding the sources of perchlorate in (NaNO3), which are also a natural Agency encourages those States with the environment, its potential health source of perchlorate (Schilt, 1979 and public water systems that may have effects, and its occurrence in drinking Ericksen, 1983). These Chilean nitrate 1,1,2,2-tetrachloroethane above the HRL water, food, human urine, breast milk, salts (saltpeter) have been mined and to evaluate site-specific protective and amniotic fluid. Section V.E explains refined to produce commercial measures and to consider whether State- the Agency’s basis for not making a fertilizers, which before 2001 accounted level guidance (or some other type of preliminary regulatory determination for about 0.14 percent of U.S. fertilizer action) is appropriate. The Agency also for perchlorate at this time and Section application (USEPA, 2001d). The plans to update the Health Advisory V.F. presents the options the Agency is USEPA (2001d) conducted a broad document for 1,1,2,2-tetrachloroethane considering to better characterize survey of fertilizers and other raw to provide more recent health perchlorate exposure and the alternate materials and found that all products information. The updated Health approaches that EPA is considering for surveyed were devoid of perchlorate Advisory will provide information to making a preliminary regulatory except for those known to contain or to any States with public water systems determination. This action provides an be derived from mined Chilean that may have 1,1,2,2-tetrachloroethane opportunity for the public to submit saltpeter. at levels above the HRL. other relevant data that may further Perchlorate has also been found in characterize exposure to perchlorate other geologic materials. Orris et al. V. What Is the Status of the Agency’s (2003) measured perchlorate at levels Evaluation of Perchlorate? through the consumption of foods and/ or through other pathways and to exceeding 1,000 parts per million (ppm At this time, the Agency is not making comment on these alternate approaches. or mg/kg) in several samples of natural a preliminary determination as to The Agency in particular seeks minerals, including potash ore from whether a national primary drinking comment on the use of urine New Mexico and Saskatchewan water regulation is needed for biomonitoring data in estimating (Canada), playa crust from Bolivia, and perchlorate. However, the Agency has perchlorate exposure. The Agency will hanksite from California. placed a high priority on making a consider any relevant information/data Texas Tech University Water regulatory determination for perchlorate provided in response to this action as Resources Center conducted a large- and will publish a preliminary the Agency determines whether to scale sampling program to determine determination as soon as possible. EPA regulate perchlorate with a national the source and distribution of is not able to make a preliminary primary drinking water regulation and perchlorate in northwest Texas determination at this time because, in how best to proceed to address groundwater (Jackson et al., 2004; order to evaluate perchlorate against the perchlorate. Rajagopalan et al., 2006). Perchlorate three SDWA statutory criteria, the was detected at concentrations greater Agency believes additional information A. Sources of Perchlorate than 0.5 g/L in 46 percent of public - may be needed to more fully Perchlorate (ClO4 ) is an anion wells and 47 percent of private wells. characterize perchlorate exposure and commonly associated with the solid Jackson et al. (2004) hypothesized that determine whether regulating salts of ammonium, magnesium, atmospheric production and/or surface perchlorate in drinking water presents a potassium, and sodium perchlorate. oxidative weathering is the source of the meaningful opportunity for health risk Perchlorate salts are highly soluble in perchlorate. In related research, reduction. This is particularly true if the water, and because perchlorate sorbs Dasgupta et al. (2005) detected Agency uses food exposure data to first poorly to mineral surfaces and organic perchlorate in many rain and snow calculate a relative source contribution material, perchlorate can be mobile in samples and demonstrated that (RSC) and corresponding health perchlorate is formed by a variety of reference level (HRL) below the 18 DWEL = [(Reference Dose x Body Weight of 70 simulated atmospheric processes drinking water equivalent level (DWEL) kg) / Drinking Water Intake of 2 L per day]. suggesting that natural, atmospherically- VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00024 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24039 derived perchlorate exists in the B. Health Effects concluded that hypothyroidism is the environment. Barron et al. (2006) Perchlorate can interfere with the first adverse effect in the continuum of developed a method for the rapid normal functioning of the thyroid gland effects of perchlorate exposure, NRC determination of perchlorate in by competitively inhibiting the recommended that ‘‘the most health- rainwater samples, with a detection transport of iodide into the thyroid. protective and scientifically valid limit between 70 and 80 ng/L. Of the ten Iodide is an important component of approach’’ was to base the perchlorate rainwater samples collected in Ireland two thyroid hormones, T4 and T3, and RfD on the inhibition of iodide uptake in 2005, perchlorate was detected in 4 the transfer of iodide from the blood by the thyroid (NRC, 2005). NRC samples at concentrations between into the thyroid is an essential step in concluded that iodide uptake inhibition, 0.075 and 0.113 g/L, and in 1 other the synthesis of these two hormones. although not adverse, is the key sample at 2.8 g/L. Kang et al. (2006) Iodide transport into the thyroid is biochemical event in the continuum of conducted seven-day experiments to mediated by a protein molecule known possible effects of perchlorate exposure determine if it was possible to produce as the sodium (Na+)—iodide (I-) and would precede any adverse health perchlorate by exposing various symporter (NIS). NIS molecules bind effects of perchlorate exposure. The chlorine intermediates to UV radiation iodide with very high affinity, but they lowest dose (0.007 mg/kg/day) in the form of high intensity UV lamps also bind other ions that have a similar administered in the Greer et al. (2002) and/or ambient solar radiation. shape and electric charge, such as study was considered a NOEL (rather than a NOAEL) because iodide uptake Perchlorate formation was demonstrated perchlorate. The binding of these other in aqueous salt solutions with initial inhibition is not an adverse effect but a ions to the NIS inhibits iodide transport concentrations of hypochlorite, chlorite, biochemical change (USEPA, 2005e). A into the thyroid, which can result in or chlorate between 100 and 10,000 mg/ summary of the data considered and the intrathyroidal iodide deficiency and L. NRC deliberations can be found in the consequently decreased synthesis of T4 After a limited investigation, the NRC report (2005) and the EPA and T3. There is compensation for Massachusetts Department of Integrated Risk Information System iodide deficiency, however, such that Environmental Quality (MA DEP, 2005) (IRIS) summary (USEPA, 2005e). found that perchlorate may be present the body maintains the serum The NRC recommended that EPA in sodium hypochlorite solutions used concentrations of thyroid hormones apply an intraspecies uncertainty factor in water and wastewater treatment within narrow limits through feedback of 10 to the NOEL to account for plants, and that the level of occurrence control mechanisms. This feedback differences in sensitivity between the depends upon storage conditions and includes increased secretion of thyroid healthy adults in the Greer et al. (2002) the initial purity of the stock solution stimulating hormone (TSH) from the study and the most sensitive (MA DEP, 2005). According to MA DEP pituitary gland, which has among its population, fetuses of pregnant women (2005), the Town of Tewksbury effects the increased production of T4 who might have hypothyroidism or conducted a small study to evaluate the and T3 (USEPA, 2005e). Sustained iodide deficiency. Because the fetus impact of storage conditions changes in thyroid hormone and TSH depends on an adequate supply of (temperature and light) on a new secretion can result in thyroid maternal thyroid hormone for its central shipment of sodium hypochlorite stock hypertrophy and hyperplasia (abnormal nervous system development during the solution. Tewksbury found that the growth or enlargement of the thyroid) first trimester of pregnancy, iodide perchlorate concentration in the new (USEPA, 2005e). uptake inhibition from low-level stock solution increased from 0.2 g/L to In January 2005, the National perchlorate exposure has been levels ranging from 995 to 6,750 g/L Research Council (NRC) of the National identified as a concern in connection depending on the storage conditions. Academies of Science (NAS) published with increasing the risk of Accounting for the large dilution factor ‘‘Health Implications of Perchlorate neurodevelopmental impairment in (e.g., 20,000 to 1 ratio) used in Ingestion,’’ a review of the current state fetuses of high-risk mothers (NRC, chlorination processes at drinking water of the science regarding potential 2005). The NRC (2005) viewed the treatment plants, MA DEP (2005) adverse health effects of perchlorate uncertainty factor of 10 as conservative concluded that ‘‘absent additional exposure and mode-of-action for and health protective given that the efforts to minimize breakdown of perchlorate toxicity (NRC, 2005). Based point of departure is based on a non- hypochlorite solutions, it would appear on recommendations of the NRC, EPA adverse effect (iodide uptake inhibition) that low levels of the perchlorate ion chose data from the Greer et al. (2002) that precedes the adverse effect in a (0.2 to 0.4 g/L) detected in a drinking human clinical study as the basis for continuum of possible effects of water supply disinfected with sodium deriving a reference dose (RfD) for perchlorate exposure. NRC concluded hypochlorite solutions could be perchlorate (USEPA, 2005e). Greer et al. that no uncertainty factor was needed attributable to the chlorination process.’’ (2002) report the results of a well- for the use of a less-than chronic study, It is not clear at this time what controlled study that measured thyroid for deficiencies in the database, or for proportion of perchlorate found in iodide uptake, hormone levels, and interspecies variability. To protect the public water supplies or entering the urinary iodide excretion in a group of 24 most sensitive human population from food chain comes from these various healthy adults administered perchlorate chronic perchlorate exposure, EPA anthropogenic and natural sources. The doses orally over a period of 14 days. derived an RfD of 0.0007 mg/kg/day significance of different sources Dose levels ranged from 0.007 to 0.5 mg/ with a ten-fold total uncertainty factor probably varies regionally. A study by kg/day in the different experimental from the NOEL of 0.007 mg/kg/day Dasgupta et al. (2006) analyzes the three groups. No significant differences were (USEPA, 2005e). principal sources of perchlorate and seen in measured serum thyroid Blount et al. (2006b) recently their relative contributions to the food hormone levels (T3, T4, total and free) published a study examining the chain. These are its use as an oxidizer in any dose group. The statistical no relationship between urinary levels of including rocket propellants, Chilean observed effect level (NOEL) for perchlorate and serum levels of TSH nitrate used principally as fertilizer, and perchlorate-induced inhibition of and total T4 in 2,299 men and women that produced by natural atmospheric thyroid iodide uptake was 0.007 mg/kg/ (ages 12 years and older), who processes. day. Although the NRC committee participated in CDC’s 2001–2002 VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00025 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24040 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules National Health and Nutrition estimated dose levels that are below the (serving more than 10,000 people). Examination Survey (NHANES).19 RfD of 0.0007 mg/kg/day. The clinical Approximately 1.9 percent (or 637) of Blount et al. (2006b) evaluated significance of the variations in T4/TSH the 34,193 samples collected (by these perchlorate along with covariates levels, which were generally within 3,858 PWSs) had positive detections of known or likely to be associated with T4 normal limits, has not been determined. perchlorate at levels greater than or or TSH levels to assess the relationship The researchers noted several equal to 4 [mu]g/L. The maximum between perchlorate and these limitations of the study (e.g., reported concentration of perchlorate hormones, and the influence of other assumption that urinary perchlorate was 420 [mu]g/L, which was found in factors on this relationship. These correlates with perchlorate levels in the a surface water sample from a PWS in covariates included sex, age, race/ stroma and tissue and preference for Puerto Rico. The average concentration ethnicity, body mass index, serum measurement of free T4 as opposed to of perchlorate for those samples with albumin, serum cotinine (a marker of total T4) and recommended that these positive detections for perchlorate was tobacco smoke exposure), estimated findings be confirmed in at least one 9.85 [mu]g/L and the median total caloric intake, pregnancy status, more large study focusing on women concentration was 6.40 [mu]g/L. post-menopausal status, premenarche with low urine iodide levels. It is also These 160 PWSs (with at least 1 status, serum C-reactive protein, hours not known whether the association analytical detection for perchlorate at fasting before sample collection, urinary between perchlorate and thyroid levels greater than or equal to 4 [mu]g/ thiocyanate, urinary nitrate, and use of hormone levels is causal or mediated by L) serve approximately 7.5 percent (or selected medications. The study found some other correlate of both, although 16.8 million) of the 225 million people that perchlorate was a significant the relationship between urine served by the 3,858 PWSs that sampled predictor of thyroid hormones in perchlorate and total TSH and T4 levels and reported results under UCMR 1. women, but not men. After finding persisted after statistical adjustments for The 16.8 million population-served evidence of gender differences, the some additional covariates known to value represents the total number of researchers focused on further analyzing predict thyroid hormone levels (e.g., people served by the 160 PWSs with at the NHANES data for the 1,111 women total kilocalorie intake, estrogen use, least one detect. Not all people served participants. They divided these 1,111 and serum C-reactive protein levels). A by these systems necessarily have women into two categories, higher- planned follow-up study will include perchlorate in their drinking water. iodide and lower-iodide, using a cut additional measures of thyroid health Some of these 160 public water systems point of 100 [mu]g/L of urinary iodide and function (e.g., TPO-antibodies, free have multiple entry points to the based on the World Health Organization T4). As EPA proceeds towards a distribution system and not all of the (WHO) definition of sufficient iodide regulatory determination for entry points sampled had positive intake.20 Hypothyroid women were perchlorate, the Agency will continue to detections for perchlorate in the UCMR excluded from the analysis. According review any new findings/studies on 1 survey. An alternative approach to the to the study authors, about 36 percent perchlorate and their relationship to system-level assessment of populations of women living in the United States thyroid function as they become served is to use an assessment at the have urinary iodide levels less than 100 available. entry (sampling) point level.22 EPA does [mu]g/L (Caldwell et al., 2005). For C. Occurrence in Water, Food, and not have population-served values for women with urinary iodide levels less Humans each entry point at the system level. than 100 [mu]g/L, the study found that However, an assessment can be 1. Sources of Perchlorate. Section urinary perchlorate is associated with a performed by assuming that each entry V.A. summarizes the potential sources decrease in (a negative predictor for) T4 (or sampling) point at a public water of perchlorate in the environment. levels and an increase in (a positive 2. Studies on Perchlorate Occurrence system serves an equal proportion of the predictor for) TSH levels. For women in Public Drinking Water Systems and/ total population-served by the system. with urinary iodide levels greater than or Drinking Water Sources. EPA In other words, for the alternative or equal to 100 [mu]g/L, the researchers included perchlorate as an analyte in assessment, the population served by found that perchlorate is a significant the 1999 Unregulated Contaminant each system is assumed to be equally positive predictor of TSH but not a Monitoring Regulation (UCMR 1) and distributed across all entry (or sampling) predictor of T4. The study found that collected drinking water occurrence points at each system. For example, if a perchlorate was not a significant data for perchlorate from 3,858 public system serves a million people and has predictor of T4 or TSH in men. The water systems (PWSs) between 2001 and 5 entry points, it is assumed that each researchers state that perchlorate could 2005. EPA analyzed the available UCMR entry point serves 200,000 people. be a surrogate for another unrecognized 1 data on perchlorate at concentrations Using this approach and counting only determinant of thyroid function. Also, greater than or equal to 4 [mu]g/L, the 22 the study reports that while large doses minimum reporting limit (MRL) for EPA EPA acknowledges that uncertainties exist in of perchlorate are known to decrease the population-served estimates for this alternative Method 314.0.21 The Agency found that assessment since the population for a system is thyroid function, this is the first time an approximately 4.1 percent (or 160) of assumed to be equally distributed across the entry association of decreased thyroid 3,858 PWSs that sampled and reported points for that system. Because the actual function has been observed at these low under UCMR 1 had at least 1 analytical population-served by an entry point is not known, levels of perchlorate exposure. Of note this alternative approach has an equal chance of detection of perchlorate (in at least 1 underestimating or overestimating the actual is that the vast majority of the entry/sampling point) at levels greater population-served by entry points with positive participants in this group had urinary than or equal to 4 [mu]g/L. These 160 detections for perchlorate. In addition, this levels of perchlorate corresponding to approach could underestimate the population systems are located in 26 states and 2 served that is potentially exposed to perchlorate territories. Of these 160 PWSs, 8 are and overestimate the level of exposure because it 19 While CDC researchers measured urinary small systems (serving 10,000 or fewer can not incorporate the effects of mixing of water perchlorate concentration for 2,820 NHANES between different entry points within the participants, TSH and total T4 serum levels were people) and 152 are large systems distribution system. This is because the approach only available for 2,299 of these participants. cannot account for the dilution that may occur 20 WHO notes that the prevalence of goiter begins 21 EPA Method 314.0 was the analytical method when water that has no detections of perchlorate is to increase in populations with a median iodide approved and used for UCMR 1 at the time of data mixed within the distribution system with water intake level below 100 [mu]g/L (WHO, 1994). collection. that has positive detections for perchlorate. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00026 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24041 the population served for the entry and represent active and standby Table 4. EPA has concluded that the points with positive detections sources (and exclude inactive, sampling results described in this (concentrations greater than or equal to destroyed, and abandoned sources, and section and Table 4 are too limited to 4 [mu]g/L), the total population served monitoring and agricultural wells) (CA characterize food-borne exposure to by these entry points with perchlorate DHS, 2006). perchlorate on a national scale. The detections is approximately 5 million. In 2005, the State of Massachusetts’s sampling data are limited in the types Section V.E provides the number of Department of Environment Protection of foods sampled, sample sizes, systems and population-served (MA DEP) reported monitoring results geographic coverage, and/or analytical estimates for other thresholds of for 85 percent (379 of 450) of its method adequacy and many were interest. community water systems and 86 targeted to foods or areas known or The California Department of Health percent (212 of 250) of its non-transient, likely to have elevated levels of Services (CA DHS) began monitoring for non-community water systems. MA DEP perchlorate. Section V.F of this action perchlorate in 1997. In 1999, CA DHS found that 9 (1.5%) of the 591 public describes the limitations of the food began requiring monitoring for water systems detected perchlorate at sampling data and also describes plans perchlorate for drinking water sources levels greater than or equal to 1 [mu]g/ for including perchlorate as part of the that were identified as vulnerable to L (the reporting limit used for a FDA’s Total Diet Study. EPA requests perchlorate contamination under modified version of EPA Method 314.0). that commenters provide the Agency California’s own State monitoring MA DEP found that the occurrence of with any additional data that may program (i.e., Unregulated Chemicals for perchlorate for these water systems further characterize the concentrations which Monitoring is Required). About could be traced to the use of blasting of perchlorate in foods commercially 60 percent (or 7,100) of all drinking agents, military munitions, fireworks, available in the U.S. When providing water sources in California (about and, to a lesser degree, sodium data to the Agency, please describe the 12,000) were monitored for perchlorate hypochlorite disinfectant (MA DEP, specific locations where the samples under the State monitoring program. 2005). were collected, including geographic Between June 2001 and June 2006, CA 3. Studies on Perchlorate Occurrence location, type of location (e.g., grocery DHS (2006) reports that 284 (about 4%) in Foods, Plants, Beverages, and Dietary store, farmer’s market, commercial field, of the approximately 7,100 water Supplements. The Food and Drug home garden), and the methodologies sources that monitored had at least 2 or Administration (FDA), the United States used to select, collect, prepare, and more positive detections for perchlorate Department of Agriculture (USDA), and analyze the samples. Please include at concentrations greater than or equal researchers from academia and industry available laboratory data reports as well to 4 [mu]g/L (the reporting limit). These have studied perchlorate in foods. Some as all relevant quality assurance/quality 284 sources supply water for 77 of these studies are described briefly in control information. drinking water systems (CA DHS, 2006) this section, and also summarized in BILLING CODE 6560–50–P VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00027 Fmt 4701 Sfmt 4725 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS EP01MY07.052 24042 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules BILLING CODE 6560–50–C FW (FDA, 2004), and ranged from not levels of 0.56 [mu]g/L and 0.45 [mu]g/ a. FDA Targeted Sampling. The FDA quantifiable (NQ) to 129 [mu]g/kg FW. L. released data on perchlorate in milk, The mean concentrations of perchlorate b. Other Published Studies. Sanchez lettuce, and bottled water in November in several varieties of lettuce are (2004) and Sanchez et al. (2005a) report 2004. To analyze food samples, FDA reported in Table 4. The mean the results of an analysis of agricultural used ion chromatography (IC)-tandem concentration of perchlorate in 104 products sampled from the lower mass spectrometry (MS/MS), referred to dairy milk samples collected in 14 states Colorado River region of Arizona and as IC–MS/MS. The quantitation limits (AZ, CA, GA, KS, LA, MD, MO, NJ, NC, California, the Imperial Valley of for perchlorate in these analyses were PA, SC, TX, VA, WA) was 5.76 [mu]g/ California, and the Coachella Valley of 0.5 [mu]g/L for bottled water, 1 [mu]g/ L (FDA, 2004), with a range from NQ to California, where irrigation water is kg by fresh weight (FW) for lettuce, and 11.3 [mu]g/L. FDA (2004) detected known or suspected to contain 3 [mu]g/L for dairy milk. The mean perchlorate in 2 of the 51 bottled water perchlorate. The studies were partially concentration of perchlorate in 128 samples representing 34 distinct sources supported by the U.S. Department of lettuce samples collected in 5 states collected in 12 states (CA, CO, GA, MD, (AZ, CA, FL, NJ, TX) was 10.3 [mu]g/kg MN, MO, NC, NE, PA, SC, TX, WI) at VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00028 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS EP01MY07.053 EP01MY07.054 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24043 Agriculture—Agricultural Research in southern California and southwestern a study of perchlorate in dairy milk, Service (USDA–ARS). Samples of Arizona. Five whole lemon trees Kirk et al. (2005) found mean iceberg, romaine, and leaf lettuce, irrigated with Colorado River water perchlorate levels of 2.0 [mu]g/L in 47 carrots, onions, sweet corn, squash, were harvested for destructive sampling. retail dairy milk samples from 11 states melons, tomatoes, peppers, broccoli, Sanchez et al. (2006) estimate that the (AK, AZ, CA, FL, HI, KS, ME, NH, NM, cauliflower, cabbage, durum wheat, and irrigation water had an average NY, PA), with a range from not detected alfalfa were analyzed for perchlorate perchlorate concentration of 6 [mu]g/L. (ND) to 11.0 [mu]g/L. A single sample using ion chromatography (IC) as the Most of the sample analysis was of soy milk was analyzed and reported primary analytical method. For these conducted using IC–MS/MS, having an to contain 0.7 [mu]g/L perchlorate (Kirk analyses, the fresh-weight method MRL of approximately 25 [mu]g/kg by et al., 2005). An earlier study by Kirk et reporting limit was not identified in dry weight (DW). In samples of tree al. (2003) found perchlorate ranging most cases, but was reported to range trunks, roots, and branches, perchlorate from 1.7 [mu]g/L to 6.4 [mu]g/L in 7 from 20 to 50 [mu]g/kg FW, depending was close to or below the MRL. dairy milk samples purchased in a city on the moisture content of the samples Perchlorate was much higher in the in Texas. (Sanchez, 2004). Sanchez et al. (2005a) leaves than the fruit (peel and pulp), Jackson et al. (2005) conducted report that the method reporting level with mean concentrations of 1,835 and limited sampling of edible and forage for iceberg lettuce was approximately 20 128 [mu]g/kg DW, respectively. vegetation in 1 Texas county and in 1 [mu]g/kg FW and for other types of Citrus samples were collected during Kansas home garden. In Texas, wheat lettuce was 25–30 [mu]g/kg FW. 2004–2005 from the lower Colorado and alfalfa were sampled from Perchlorate in the irrigation water River Valley, the University of Arizona commercial fields irrigated with ranged from 1.5 to 8.0 [mu]g/L over the Research Farm, the Coachella Valley, groundwater containing perchlorate period of the survey (Sanchez et al., and Los Angeles County. All analyses of from an unknown source, and a 2005a). fruit pulp were conducted using IC–MS/ cucumber was sampled from an Sanchez et al. (2005a) analyzed 44 MS with an approximate MRL of 2.5 irrigated home garden. In Kansas, samples of iceberg lettuce heads that [mu]g/kg FW. For the 86 citrus samples cantaloupe, cucumber, and tomatoes had been trimmed of frame and wrapper collected, the perchlorate concentration were sampled from an irrigated home leaves, which are usually removed in the fruit pulp ranged from below garden near a slurry explosives site. before the lettuce is consumed. detection to 37.6 [mu]g/kg FW. Mean Researchers used IC for sample analysis Perchlorate was quantified in 5 of the concentrations in lemons (33 samples), but did not report fresh-weight samples (ranging from 23 to 26 [mu]g/ grapefruit (15 samples), and oranges (28 detection limits. Perchlorate was 23 kg FW), perchlorate was not detectable samples) were 2.3, 3.3, and 7.4 [mu]g/ detected in all 12 samples of winter in 6 samples, and the results of the kg FW, respectively. wheat heads (whole, including the remaining samples were less than the Sanchez et al. (2005b) surveyed chaff) at a mean concentration of 2,000 method reporting limit, which the perchlorate occurrence in lettuce and [mu]g/kg FW but perchlorate was not authors defined as ‘‘a detectable peak other leafy vegetables produced outside detected in wheat endosperm (2 among duplicates and/or replicates but the lower Colorado River region. samples)24. The mean perchlorate below a level that can be quantitated.’’ Samples were analyzed by IC, with a concentration in 3 samples of alfalfa Perchlorate concentrations in 10 minimum reporting level of was 2,900 [mu]g/kg FW. A cucumber samples of romaine and green leaf approximately 20 to 40 [mu]g/kg FW, sample from a Texas home garden lettuce ranged from less than the depending on the leafy vegetable type. contained 40 [mu]g/kg FW perchlorate; method reporting limit to 81[mu]g/kg Results of some of the more heavily a sample of irrigation water from this FW (Sanchez, 2004). sampled food items are presented in garden contained 20.7 [mu]g/L As shown in Table 4, Sanchez (2004) Table 4. perchlorate. In the Kansas home garden, also detected perchlorate in samples of While not shown in Table 4, Sanchez the cucumber sample contained 770 melons, tomatoes, and peppers, but at et al. (2005b) performed additional [mu]g/kg FW perchlorate, the levels below the method reporting limit. analysis by partitioning the leafy cantaloupe sample contained 1,600 Perchlorate was not detected in carrots, vegetable samples by type of culture. [mu]g/kg FW perchlorate, and 2 samples onions, sweet corn, squash, and durum Perchlorate was detected in 70 of 268 of tomato contained 42 and 220 [mu]g/ wheat. Concentrations of perchlorate in samples of conventionally-grown leafy kg FW perchlorate. The reported 10 samples of alfalfa ranged from 109 to vegetables and 72 of 170 samples of concentration of perchlorate in 668 [mu]g/kg FW. Six of the 10 alfalfa organically-grown leafy vegetables. The irrigation water for the Kansas home samples were sent to FDA for range of perchlorate concentrations was garden was 81 [mu]g/L. EPA notes that confirmatory analysis by IC–MS/MS. ND to 104 [mu]g/kg FW in conventional the perchlorate levels in irrigation water The FDA results were generally lower leafy vegetables and ND to 628 [mu]g/ samples associated with these two home than those of the corresponding samples kg FW in organic leafy vegetables. gardens were significantly higher than by Sanchez (2004), ranging from 121 to Sanchez et al. (2005b) analyzed the in the vast majority of surface and 382 [mu]g/kg FW. results using regression analysis and Sanchez et al. (2006) conducted ground water samples in the US. estimated that the median perchlorate Aribi et al. (2006) developed an studies to evaluate the uptake and concentration in organically-grown distribution of perchlorate in citrus trees analytical method for perchlorate that samples was 2.2 times higher than in uses ion chromatography with and the occurrence of perchlorate in conventionally-grown samples. The lemons, grapefruit, and oranges grown suppressed conductivity and regression analysis also suggested that electrospray ionization tandem mass variation among sampling locations was 23 Sanchez (2004) presents somewhat different greater than variation among lettuce results. Specifically, of the 44 samples of ‘‘edible 24 A wheat kernel (seed) has three major parts— head’’ lettuce, perchlorate was quantified in one of types. the bran, the germ, and the endosperm. The the samples (26 [mu]g/kg), perchlorate was not Researchers at Texas Tech University majority of the wheat kernel is the endosperm, detectable in 6 samples, and the remaining analyzed samples of dairy and soy milk which is the portion of the kernel that is retained sampling results were qualified as VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00029 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24044 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules spectrometry (IC–ESI–MS/MS). The mg/day at the recommended daily dose) associated donor information. method was used to measure was found in a prenatal vitamin; in the Perchlorate was detected in all of the perchlorate in samples of various food remaining prenatal and children’s urine samples, with concentrations products, including fresh/canned fruits vitamins perchlorate did not exceed 28 ranging from 0.66 to 21 [mu]g/L. The and vegetables, wine, beer, and other [mu]g/kg. The study noted that ‘‘vitamin authors cited dietary exposure as a beverages. Most samples were and mineral supplements are typically potential source of perchlorate because purchased in grocery and liquor stores formulated to include the perchlorate was found only at low levels in greater Toronto, Canada, between Recommended Daily Allowance (RDA) (0.1—0.2 [mu]g/L) in area tap water January 2005 and February 2006. of iodine, a factor that would provide samples (Valentin-Blasini et al., 2005). Produce samples originated from many protection against any possible impacts Valentin-Blasini et al. (2005) also different parts of the world and all of microgram levels of perchlorate analyzed the urine samples for samples contained measurable amounts found in these supplements.’’ creatinine, which is a metabolic of perchlorate. However, the survey was Perchlorate was also detected at 740 breakdown product in muscles that is limited to only a few samples of each [mu]g/kg in a sample of kelp granules (a eliminated from the body in urine at a food. Products from California, Chile, flavor enhancer), which equates to 2.2 predictable rate. When adjusted for Costa Rica, Guatemala, and Mexico had [mu]g perchlorate per serving. urinary creatinine content, the reported the highest levels of perchlorate. Martinelango et al. (2006a) measured range of perchlorate in the samples is Products from Canada and China had perchlorate in seaweed, which is often 1.0 to 35 [mu]g of perchlorate per gram the lowest levels of perchlorate. The used as a source of iodide in food and of creatinine. The median perchlorate highest detection was in cantaloupe nutritional supplements. Martinelango concentration was 3.2 [mu]g/L (7.8 from Guatemala (463.50 [mu]g/kg FW). et al. (2006a) collected samples of 11 [mu]g/g creatinine). The researchers Analysis of raw asparagus (39.900 different species of seaweed growing off stated that only 1 sample from the [mu]g/kg FW) and cooked asparagus the coast of northeastern Maine. Atlanta population contained (24.345 [mu]g/kg FW) demonstrated that Perchlorate was detected in all species, perchlorate at a level slightly in excess perchlorate can remain in food with concentrations ranging from 29 to of the amount expected to be excreted processed at a high temperature. 878 [mu]g/kg DW. The iodide content in by an individual exposed to perchlorate Perchlorate concentrations in 8 samples the samples was much higher, ranging at the reference dose of 0.0007 mg/kg/ of produce from the U.S. ranged from from 16 to 3,134 mg/kg DW. day (Valentin-Blasini et al., 2005). 0.094 [mu]g/kg FW (for blueberries) to Martinelango et al. (2006a) found that Specifically, assuming that perchlorate 19.29 [mu]g/kg FW (for green grapes). samples of Laminaria species Aribi et al. (2006) analyzed 77 is excreted uniformly in urine concentrated iodide more selectively throughout the day, a urinary excretion samples of wine and 144 samples of than perchlorate. Laminaria is a genus beer from many parts of the world. All level of 34 [mu]g perchlorate per gram of large brown seaweeds that are creatinine would be associated with a samples contained measurable amounts commonly used in kelp tablets. of perchlorate. The wine sample with daily perchlorate intake of 0.0007 mg/ Martinelango et al. (2006a) also kg/day, for a 70 kg male that excretes the single highest concentration of analyzed 4 seaweed samples that had perchlorate, 50.250 [mu]g/L, was from creatinine at a typical rate of 1.44 grams been washed with deionized water and per day (g/day). These assumptions are Portugal. Overall, wine samples from found that a single wash removed 38 to Chile contained the highest imprecise for individual exposure 73 percent of the perchlorate and 34 to assessment but allow for spot urine concentrations of perchlorate, ranging 44 percent of the iodide. from 5.358 to 38.88 [mu]g/L in 8 perchlorate excretion to be related to the samples. Twelve samples of wine from D. Occurrence Studies on Perchlorate in reference dose for toxicological the U.S. contained perchlorate Human Urine, Breast Milk, and perspective. Estimating perchlorate concentrations ranging from 0.197 to Amniotic Fluid exposure from a single spot urine 4.593 [mu]g/L. Results from analysis of Recently researchers have used the sample (as opposed to a sample beer samples varied substantially among results of the analysis of urine samples collected continuously over a period of countries, with an overall range from to estimate human exposure to time) is imprecise due to the episodic 0.005 [mu]g/L (Ireland) to 21.096 [mu]g/ perchlorate. Ingested perchlorate is not nature of perchlorate exposure and the L (France). Concentrations of metabolized by humans and is excreted short half-life of perchlorate in the perchlorate in 8 beer samples from the largely in the urine (Merrill et al., 2005). human body. The precision of estimated U.S. ranged from 0.364 to 2.014 [mu]g/ The CDC’s National Center for individual perchlorate exposure can be L. Environmental Health (NCEH) improved by more precise estimation of Snyder et al. (2006) measured developed a sensitive and selective 24-hour creatinine excretion based on perchlorate in dietary supplements and analytical method to analyze sex, height, weight, and age as described flavor enhancing ingredients collected perchlorate in human urine (Valentin- by Mage et al. (2004). In addition, from various vendors in Las Vegas, NV, Blasini et al., 2005). The method uses imprecision stemming from the episodic and Seattle, WA. Analyses were ion chromatography coupled with nature of perchlorate exposure can be performed using LC–MS/MS with a electrospray ionization tandem mass reduced with increased sampling. limit of detection between 2 and 5 spectrometry (IC/MS/MS) and achieves The analytical method developed by [mu]g/kg. Perchlorate was detected in an MRL of 0.025 [mu]g/L in human Valentin-Blasini et al. (2005) was 20 of 31 analyzed supplements, with urine. The authors report that the further used by Blount et al. (2006a) to detectable concentrations ranging from method is robust enough to process evaluate urine samples from 27 10 to 2,420 [mu]g/kg. Based on first-morning-void urine samples, which volunteers with differing dietary habits. manufacturers’ recommended intake of are samples of the first voiding of urine Blount et al. (2006a) collected first- the supplements, the resulting daily oral upon waking. morning-void urine specimens from doses of perchlorate would range from Valentin-Blasini et al. (2005) analyzed volunteers living in the Atlanta area. 0.03 to 18 [mu]g/day. Twelve of the urine samples from 61 healthy adult The study volunteers self-assessed their supplements tested were prenatal or donors who lived in the area of Atlanta, consumption of milk, dairy products, children’s vitamins. The highest level of Georgia. The urine samples were and green/leafy vegetables within the 16 perchlorate (2,420 [mu]g/kg or 0.018 provided anonymously, without hours before the sample was collected. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00030 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24045 The samples were grouped into 2 [mu]g/g creatinine). Blount et al. (2006c) breast milk perchlorate levels were categories (‘‘one or fewer servings’’ and estimated a total daily perchlorate dose highly variable and no significant ‘‘three or more servings’’) based on total for each adult and found a median dose correlations could be established consumption of these selected foods. of 0.066 [mu]g/kg/day (about one tenth between breast milk perchlorate and Total daily perchlorate exposure was of the RfD) and a 95th percentile of either urine perchlorate or breast milk calculated using a bodyweight of 70 kg 0.234 [mu]g/kg/day (about one third of iodide concentrations for the and a creatinine excretion rate of 1.44 g/ the RfD). Eleven adults (0.7%) had individuals evaluated in these Chilean day, assuming that each first-morning estimated perchlorate exposure in cities (T[eacute]llez et al., 2005). Kirk et void urine sample was representative of excess of the RfD (0.7 [mu]g/kg/day). al. (2006) evaluated variations of iodide, that individual’s daily perchlorate The highest estimated exposure was thiocyanate and perchlorate in human exposure. Each volunteer also collected 3.78 [mu]g/kg/day. Because of daily milk samples. These authors suggest a drinking water sample from home and variability in diet and perchlorate that if the overall intake of iodide is work. Blount et al. (2006a) analyzed exposure, and the short residence time sufficient, it is unlikely that milk with drinking water samples with the same of perchlorate in the body, these single an occasional low iodide or high method used for urine analysis and sample measurements may overestimate perchlorate content would pose a major estimated exposure from drinking water long-term average exposure for risk to infants. However, their limited based on a body weight of 70 kg and individuals at the upper end of the data (evaluating only 10 women) show daily consumption of 2 liters of water distribution and may underestimate the that the milk of some women may not per day. The mean creatinine-adjusted long-term average exposure for supply infants with adequate iodide and urinary perchlorate level was 1.8 times individuals at the lower end of the higher for individuals who identified they suggest that it may be important to distribution. Daily perchlorate dose is base risk assessments for perchlorate themselves as consuming three or more not presented for children and servings of milk, dairy products, and/or exposure on the iodide to perchlorate adolescents due to the limited ratio or the ratio of iodide to a green/leafy vegetables (6.13 versus 3.45 validation of formulas for these age ‘‘selectively-weighted sum of iodide [mu]g/g creatinine). There were no groups (Blount et al., 2006c). significant differences in the perchlorate Valentin-Blasini et al. (2005) and uptake inhibiting agents.’’ levels in the drinking water samples of T[eacute]llez et al. (2005) analyzed Blount and Valentin-Blasini (2006) the 2 diet groups, which ranged from urine samples of pregnant women in 3 developed a sensitive and selective <0.05 to 0.25 [mu]g/L with a median of cities in Chile and found higher median method for quantifying iodide, 0.10 [mu]g/L. Using a median drinking levels of urinary perchlorate in cities perchlorate, thiocyanate, and nitrate in water level of 0.10 [mu]g/L, Blount et al. with higher concentrations of human amniotic fluid. The analytical (2006a) estimated that the perchlorate perchlorate in tap water. Based on an limit of detection for perchlorate was dose from drinking water was 0.003 assessment of drinking water intake, the calculated to be 0.020 [mu]g/L. Samples [mu]g/kg/day. Compared to this researchers determined that, in all 3 of amniotic fluid at 15 to 20 weeks drinking water estimate, the total cities, there was an additional source of gestation were collected from 48 healthy perchlorate dose estimate based on perchlorate for the study participants women in an Eastern U.S. city for mean urinary perchlorate excretion was that may be explained by dietary (food) analysis. Perchlorate was found in all 24 times higher (0.071 [mu]g/kg/day) intake (T[eacute]llez et al., 2005). This samples tested and exhibited a log- and 42 times higher (0.126 [mu]g/kg/ gap between estimated perchlorate normal distribution. The perchlorate day) for the low-consumption and high- exposure and perchlorate intake from concentrations ranged from 0.057 to consumption diet groups, respectively. tap water consumption ranged from 21.7 0.71 [mu]g/L with a median value of The overall range of perchlorate found [mu]g/day to 33.8 [mu]g/day in the 3 0.18 [mu]g/L. in urine was 0.94 to 17 [mu]g/g Chilean cities (T[eacute]llez et al., creatinine with a median of 4.2 [mu]g/ 2005). E. Status of the Preliminary Regulatory g creatinine. Martinelango et al. (2006b) developed Determination for Perchlorate In the largest study of its kind, Blount a method to measure perchlorate in et al. (2006c) measured perchlorate in human urine with a limit of detection of As stated earlier, the Agency is not urine samples collected from a 0.080 [mu]g/L, and reported analytical making a preliminary regulatory nationally representative sample of results of 9 spot urine samples from determination for perchlorate in this 2,820 U.S. residents, ages 6 years and male and female volunteers. Perchlorate notice. The Agency believes that older, as part of the 2001–2002 was present in all samples analyzed, at additional information is needed on the NHANES. Blount et al. (2006c) detected concentrations ranging from 2.2 to 14.9 sources of human exposure if it decides perchlorate at concentrations greater [mu]g/L, with a median value of 8.1 to base its determination regarding than 0.05 [mu]g/L in all 2,820 urine [mu]g/L. health risk reduction potential on a samples tested, with a median Other studies have investigated health reference level (HRL) derived concentration of 3.6 [mu]g/L (3.38 perchlorate in human breast milk. Kirk from the RfD and the relative source [mu]g/g creatinine) and a 95th et al. (2005) analyzed 36 breast milk contribution (RSC) for drinking water. percentile of 14 [mu]g/L (12.7 [mu]g/g samples from 18 states (CA, CT, FL, GA, Under this approach, the Agency would creatinine). Only 0.7% of the study HI, MD, ME, MI, MO, NC, NE, NJ, NM, use the RfD and RSC to estimate an HRL participants had an estimated NY, TX, VA, WA, WV) and found and then use this HRL as a benchmark perchlorate dose in excess of 0.0007 mg/ perchlorate concentrations in all against which to conduct an evaluation kg/day. Women of reproductive age (15– samples ranging from 1.4 to 92.2 [mu]g/ of the occurrence data. In conducting 44 years) had a median urinary L in all samples, with a mean such an assessment for the 6 non- perchlorate concentration of 2.9 [mu]g/ concentration of 10.5 [mu]g/L. carcinogens discussed previously in this L (2.97 [mu]g/g creatinine) and a 95th T[eacute]llez et al. (2005) report action, EPA used a 20 percent RSC, percentile of 13 [mu]g/L (12.1 [mu]g/g maternal parameters for participants which is the lowest and most creatinine). The demographic with the from the study in Chile. Breast milk conservative RSC used to estimate an highest concentration of urinary samples indicated that a significant HRL. Since the initial screening of the perchlorate was children (6–11 years), amount of perchlorate leaves the body occurrence data against the HRL who had a median urinary perchlorate of the nursing mother through breast resulted in a preliminary negative concentration of 5.2 [mu]g/L (5.79 milk, in addition to urine. However, the determination, the Agency found that it VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00031 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24046 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules was not necessary to further evaluate perchlorate in drinking water presents a health risk reduction if it uses this the RSC for these contaminants. In the meaningful opportunity for health risk approach. case of perchlorate, the Agency is not at reduction. EPA recognizes that system-level the point of being able to make either a Table 5 shows the number of systems population estimates shown in Table 5 negative or a positive determination and population served that would may be conservative because some using this approach because it is not yet systems have multiple entry points to exceed the HRL under various RSC clear what an appropriate RSC for the distribution system and not all entry scenarios and the sensitivity of this perchlorate is. If EPA were to use a points had a positive detection for default RSC of 20% for perchlorate, the estimate to relatively small changes in perchlorate in the UCMR 1 survey. resulting HRL would be 5 [mu]g/L. the estimated RSC. For example, Hence, to derive a less conservative Approximately 3.16% of the 3,858 increasing the RSC from 20 to 30 population estimate (last column in PWSs in the UCMR1 data set had at percent would lower the estimated Table 5), EPA assumed that the least one detect of perchlorate greater number of systems impacted by about a population for each system is equally than or equal to 5 [mu]g/L. Given this third and the estimated population distributed over all of the entry (or level of occurrence at the default- served by about half. Hence, the choice sampling) points and estimated a derived HRL, the Agency believes a of an appropriate RSC and resulting population-served value based on entry better informed RSC and HRL would be HRL could impact EPA’s determination points that had at least 1 analytical needed to use this approach to of whether regulation of perchlorate detection for perchlorate at levels determine whether regulation of represents a meaningful opportunity for greater than each of the HRL thresholds. TABLE 5.—UCMR 1 OCCURRENCE AND POPULATION ESTIMATES FOR PERCHLORATE AT VARIOUS HRL THRESHOLDS a Population Population estimate for served by PWS entry or sample entry or sam- Estimated HRL thresh- PWSs with at least 1 PWSs with at ple points hav- RSC scenarios ≤ points with at least 1 least 1 detec- (percent) olds based on various detection threshold of detection ≤ threshold of ing at least 1 RSC scenarios b interest tion ≤ thresh- interest c detection ≤ old of interest threshold of d interest e 20 ...... 5 [mu]g/L ...... 3.16% (122 of 3,858) ...... 1.88% (281 of 14,984) .... 14.6 M 4.0 M 30 ...... 7 [mu]g/L ...... 2.13% (82 of 3,858) ...... 1.14% (171 of 14,984) .... 7.2 M 2.2 M 40 ...... 10 [mu]g/L ...... 1.35% (52 of 3,858) ...... 0.65% (97 of 14,984) ...... 5.0 M 1.5 M 50 ...... 12 [mu]g/L ...... 1.09% (42 of 3,858) ...... 0.42% (63 of 14,984) ...... 3.6 M 1.2 M 60 ...... 15 [mu]g/L ...... 0.80% (31 of 3,858) ...... 0.29% (44 of 14,984) ...... 2.0 M 0.9 M 70 ...... 17 [mu]g/L ...... 0.70% (27 of 3,858) ...... 0.24% (36 of 14,984) ...... 1.9 M 0.8 M 80 ...... 20 [mu]g/L ...... 0.49% (19 of 3,858) ...... 0.16% (24 of 14,984) ...... 1.5 M 0.7 M 100 ...... 25 [mu]g/L ...... 0.36% (14 of 3,858) ...... 0.12% (18 of 14,984) ...... 1.0 M 0.4 M Footnotes: a These data represent summary statistics for the 3,858 public water systems that have sampled for perchlorate as a part of the UCMR 1 sur- vey. b HRL threshold = [(RfD of 0.0007 mg/kg/day x 70 kg BW for pregnant female) / (2 L DWI)] x the RSC scenario. Each HRL threshold value is converted from mg/L to [mu]g/L units and then rounded to the nearest whole number. c The entry/sample-point-level population served estimate is based on the system entry/sample points that had at least 1analytical detection for perchlorate greater than the HRL threshold of interest. The UCMR 1 small system survey was designed to be representative of the nation’s small systems, not necessarily to be representative of small system entry points. d The system-level population served estimate is based on the systems that had at least 1analytical detection for perchlorate greater than the HRL threshold of interest. e Because the population served by each entry/sample point is not known, EPA assumed that the total population served by a particular sys- tem is equally distributed across all entry/sample points. To derive the entry/sample point-level population estimate, EPA summed the population values for the entry/sample points that had at least 1 analytical detection greater than the threshold of interest. Table 5 also includes information on the HRL is derived using an RSC to background exposure of subjects in the the effects of using an RSC of 100% account for other sources of exposure. Greer study and whether it should (that is, using an HRL set at the DWEL Use of an RSC to derive the HRL is consider the background exposure of of 24.5 [mu]g/L, rounded to a whole clearly appropriate when the RfD or these subjects in determining an HRL number). Crawford-Brown et al. (2006), cancer slope factor is derived from for perchlorate. in an estimate of risk variability from animal studies with carefully controlled While several States have perchlorate exposure through exposure. Crawford-Brown et al. recommended guidelines or public community water systems, noted that suggest, however, that an RSC is not health goals for perchlorate, EPA the subjects in the original 2002 Greer necessary for perchlorate because there recognizes that at least 1 state, et al., study (on which the RfD of .0007 is no reason to assume that the Massachusetts,25 has already mg/L was based) presumably had other background exposure of the study promulgated a final drinking water sources of perchlorate exposure outside subjects was different than that of the standard for perchlorate, that other of the study and suggested that it may general population. EPA notes that the States may set drinking water standards be appropriate to view their results as sample size in the Greer study was in the future, and that these standards reflecting the effects of incremental small and EPA is not aware of data on exposure to perchlorate above the their background exposure to 25 Massachusetts promulgated a final drinking water standard of 2 [mu]g/L for perchlorate on July background levels already in food and perchlorate or how representative it may 28, 2006. For more information about the final water rather than the effects of total be. EPA requests comment on whether standard, see http://www.mass.gov/dep/public/ exposure, as is implicitly assumed when information is available on the press/pchl0706.htm (MA DEP, 2006). VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00032 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24047 could impact national occurrence determine the RSC allowed for drinking Valentin-Blasini et al. (2005), Tollez et estimates once these standards are fully water and to set health goals (i.e., al. (2005), and Blount et al. (2006c). implemented. Maximum Contaminant Level Goals) for While this would be the first time the Agency has used biomonitoring data to F. What Are the Potential Options for several inorganic compounds (e.g., Characterizing Perchlorate Exposure antimony, cadmium, chromium, and assist EPA in making a preliminary and Proceeding With the Preliminary selenium). Under the TDS, foods are regulatory determination for a CCL Regulatory Determination for sampled at retail outlets, prepared as contaminant, the Agency believes that Perchlorate? they would be consumed, and analyzed estimating perchlorate exposure among for a variety of analytes (e.g., nutrients, large populations using urinary While the Agency recognizes that pesticides, industrial chemicals). perchlorate excretion data may be food and other pathways may be Approximately 280 foods, covering a appropriate for the following reasons: important sources of perchlorate broad spectrum of the diet, are currently VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00033 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24048 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules determination for perchlorate. EPA also (2006c) estimated a total daily The RSC value could be derived by requests comment on the relevance, if perchlorate dose for adults from urine subtracting the estimated perchlorate any, to a regulatory determination for data and found a median dose of 0.066 exposure for exclusive bottled water perchlorate, of the Blount et al (2006b) [mu]g/kg/day (about one tenth of the drinkers from the RfD of 0.0007 mg/kg/ study, which showed an association RfD) and a 95th percentile of 0.234 day, using the remainder as the between T4/TSH levels in women and [mu]g/kg/day (about one third of the allowance for drinking water. One urinary perchlorate concentrations at RfD). If EPA were to use the estimated limitation of this methodology is that levels below the RfD (see Section V.B). 95th percentile total dose from the the perchlorate concentration of the EPA could also use the 2001–2002 Blount study as if it represented the bottled water used by this NHANES NHANES urine data to qualitatively exposure from food alone, this would population is not known. Hence, we evaluate the importance of the water suggest a residual screening-level RSC would have to assume that the bottled contribution to overall exposure. For of about 70% allocated to water. One water concentration data collected by this approach, the Agency could merge possible limitation of this approach is FDA (2004) is representative of the data from the 2001–2002 NHANES and that the Blount study estimates perchlorate concentration in the bottled UCMR 1 and compare the total exposure for adults only. Therefore, an water used by the NHANES exclusive perchlorate exposure values (based on RSC developed based upon this data bottled water population. Another the urine data) for the population of would not necessarily be representative limitation of this approach is that it individuals whose drinking water of children. EPA requests comment on would not subtract out the fraction of contains perchlorate at various using this approach as the basis for the drinking water intake that comes concentration levels, ranging from non- deriving a screening-level RSC. from water used for cooking purposes detect to the upper end of the b. Use of the Urine Data and UCMR (since bottled water is probably not used occurrence distribution. The intent of 1 to Deduce Exposure from Other by most subjects in cooking and this analysis would be to permit the Sources and Derive the RSC. household food preparation). It would Agency to determine whether total Alternately, for those NHANES survey thus produce a conservative (health perchlorate exposure (as measured in subjects served by public drinking water protective) estimate of the RSC as it urine) is meaningfully correlated with systems with positive detections for would overestimate the fraction of total concentrations in local public drinking perchlorate (based on UCMR 1), EPA exposure coming from food. water supplies, though EPA would only could estimate the expected perchlorate use these results qualitatively because it dose contributed by drinking water G. Next Steps is not possible to match up individual (using individual water consumption After the Agency evaluates and urine samples with individual drinking data from the NHANES survey thoroughly reviews public comments water exposures. However, the results combined with UCMR 1 data for the and any new information/data on could be useful in determining at least area in which they live) and subtract it perchlorate obtained following this qualitatively the potential significance from the total perchlorate dose (based notice, and performs the necessary of drinking water exposure for total on urinary perchlorate excretion data) to analyses, the Agency intends to move exposure. If there were not a significant calculate the amount contributed by expeditiously to publish a preliminary correlation between public water system food. Subtraction of this calculated food regulatory determination for perchlorate occurrence and individual contribution from the RfD would yield perchlorate. Depending on how quickly exposure as measured through the amount allowed for drinking water, the Agency is able to complete the biomonitoring, this might suggest that which could be divided by the RfD to necessary analyses and determine the there is not a meaningful opportunity calculate an RSC. One limitation of this best approach for making this for health risk reduction through methodology would be the assumption determination, EPA may be able to regulation of drinking water. that subjects in the NHANES study are publish the preliminary determination The Agency could also potentially use uniformly consuming drinking water in time to include a final determination the 2001–2002 NHANES urine data to that contains perchlorate at the for perchlorate as part of the final CCL derive an RSC to use for drinking water. concentration indicated in the UCMR 1 2 regulatory determination, which is This could potentially be done in data for their area. due by July, 2008. If not, the Agency several different ways as follows. c. Use of Urinary Biomonitoring Data will publish its final determination for a. Use of Urinary Biomonitoring Total from Exclusive Bottled Water Drinkers perchlorate as soon thereafter as Exposure Value to Estimate an RSC. to Estimate an RSC. The 2001–2002 possible. EPA does not intend to wait One possible approach to estimating an NHANES data includes urinary until the CCL 3 regulatory RSC for water would be to use the urine perchlorate data for populations who determination cycle to complete its data to estimate total perchlorate exclusively drink bottled water. As determination for perchlorate. exposure, then subtract this exposure noted in section V.C.3.a, FDA (2004) value from the reference dose and allow tested 51 samples of bottled water from VI. What About the Remaining CCL 2 the remainder as the exposure limit for 34 distinct sources in 12 states and Contaminants? water. The allowed remainder divided detected perchlorate in 2 samples (at As previously stated, EPA is only by the RfD would be the RSC for levels of 0.56 [mu]g/L and 0.45 [mu]g/ making regulatory determinations on drinking water. This approach would L). These levels are well below the MRL CCL 2 contaminants that have sufficient yield a conservative RSC value because for the UCMR 1 data and would not information to support a regulatory the exposure used to represent food contribute significant amounts of determination at this time. Section V would actually correspond to both food perchlorate relative to the RfD. If the discusses the status of EPA’s review of and drinking water exposure, whereas, population of exclusive bottled water perchlorate. For the 30 remaining if it were possible to estimate the drinkers is sufficiently representative of chemicals and the 9 microbial exposure from food alone, the relative the U.S. population, these data pathogens, the Agency lacks adequate amount allowed for water would be potentially could be used to estimate the information in the areas of health effects larger (resulting in a higher RSC and contribution of perchlorate exposure or occurrence or both. higher health reference value). As coming from food and allow the Agency The Agency continues to conduct discussed in Section V.D, Blount et al. to estimate an RSC for drinking water. research and/or to collect information VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00034 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24049 on the remaining CCL 2 contaminants to protective against developmental gather more information about the fill identified data gaps. Stakeholders toxicity. occurrence of the ESA and OA may be concerned that regulatory Metolachlor has been evaluated for degradates in finished water (along with determinations for such contaminants carcinogenic activity in both rats and the metolachlor parent), the Agency has should not necessarily wait until the mice. No treatment-related cancer added these degradates and their parent end of the next regulatory determination effects were observed in 2 studies using to the second unregulated contaminant cycle. In this regard, it is important to mice. In studies using rats, metolachlor monitoring regulation (UCMR 2; 70 FR recognize that the Agency is not caused a significant increase in liver 49093; USEPA, 2005g). While EPA precluded from conducting research, nodules and carcinomas in high dose awaits the results of the UCMR 2 survey, monitoring, developing guidance or females. Negative results from the Agency is planning to update the health advisories, and/or making a mutagenicity studies suggest that health advisory for metolachlor to determination prior to the end of the tumors may result from a nonmutagenic include the ESA and OA degradates. next cycle. In addition, the Agency is mode of action. In 1991, a peer review The Agency requests comment from the not precluded from regulating a committee recommended that public as to whether updating the health contaminant at any time when it is metolachlor be classified as a possible advisory to include these degradates necessary to address an urgent threat to human carcinogen based on increases in will be useful for States and public public health, including any liver tumors in the female rat. However, water utilities. contaminant not listed on the CCL. a peer review conducted in July 1994 In addition, the Agency requests Because the focus of this action is to recommended that the evidence for answers to the following questions and announce and solicit public comment cancer was suggestive and should not be any available data: on the Agency’s preliminary quantified. This recommendation was VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00035 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24050 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules the status of the MTBF health risk or above, representing approximately source waters exceeded 20 [mu]g/L, and assessment and interested members of 0.33 percent (or 754 thousand of 226 the three highest concentration sources the public should check that Web site to million) of the population served by the ranged from 6 [mu]g/L to 19.5 [mu]g/L find out the latest schedule. public water systems that sampled for (Grady, 2003). Of the areas known or The Agency collected data on MTBE MTBE. (USEPA, 2006a) suspected of having MTBE in the occurrence as part of the UCMR 1 Of the PWSs reporting detections at or Focused Survey, USGS found that 5 survey. In addition, EPA evaluated above 5 [mu]g/L (the MRL), 15 were percent (e.g., ground waters for 7 of the several sources of supplemental ground water systems and 4 were 134 systems) had concentrations greater occurrence information described in the surface water systems. One small than 20 [mu]g/L (Delzer and Ivahnenko, supporting documentation for this ground water system (49 [mu]g/L) and 3 2003a). action entitled ‘‘Regulatory large ground water PWSs (48 [mu]g/L, USGS also reviewed the literature for Determinations Support Document for 36 [mu]g/L, and 33.2 [mu]g/L) reported national, regional, and State MTBE Selected Contaminants from the Second MTBE at levels greater than 20 [mu]g/ information (Delzer and Ivahnenko, Drinking Water Contaminant Candidate L (the lower end of the taste and odor 2003b), including 13 state-wide List (CCL 2)’’ (USEPA, 2006a). Section threshold). One large surface water assessments. This information is VI.B.2 provides a summary of some of system (33 [mu]g/L) reported MTBE at summarized in Table 6. USGS noted the data and information on MTBE levels greater than 20 [mu]g/L. The that because study objectives varied, occurrence collected to date. remaining 14 systems had detects information varied in terms of reporting 2. Occurrence Information between 5 [mu]g/L and 20 [mu]g/L levels, sampling frequencies, and a. UCMR 1. EPA collected sampling (USEPA, 2006a). sources (e.g., ambient water, public and results for MTBE from over 98.9 percent b. USGS studies/surveys/reviews. In homeowner wells, treated drinking (3,068 of 3,100) of the large PWSs and 2003, the USGS reported results of water). over 99.5 percent (796 of 800) of the national source water sampling Previously, USGS (Grady and Casey, small systems required to sample under (previously introduced in section 2001) studied MTBE occurrence in the UCMR 1. Based on these data, 19 public III.B.2.a.(2)). USGS sampling included a drinking water of 12 States (New water systems (0.49 percent of the 3,864 random study of a representative sample England and the Mid-Atlantic). The sampled) in 14 states (CA, CT, GA, IL, of untreated source waters (known as study found less than 1 percent of the MA, MO, NH, NJ, NM, NY, PA, SD, TN, the ‘‘Random Survey’’) and a study of CWSs had drinking water samples at or and WV) reported MTBE occurrence in source waters from areas known or above 20 [mu]g/L, while 7.8 percent of drinking water. These 19 systems suspected of having MTBE (known as the CWSs had MTBE at 1 [mu]g/L or reported MTBE in 26 samples at the the ‘‘Focused Survey’’). In the Random higher. minimum reporting level of 5 [mu]g/L Survey, USGS found that none of the BILLING CODE 6560–50–P BILLING CODE 6560–50–C surveyed the States under a grant from that were contaminated by MTBE at c. New England Interstate Water EPA’s Office of Underground Storage some level, and of those, 5 States (ME, Pollution Control Commission Tanks (UST). Twenty-six States (NEIWPCC). In 2003, the NEIWPCC estimated that they had public wells VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00036 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS EP01MY07.055 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24051 NH, NJ, DE, and MD) estimated having interesting, the data as reported on the TABLE 7.—STATE ACTIONS BANNING MTBE (STATE-WIDE) [Adapted from USEPA, 2004g and McCarthy and Tiemann, 2005] State Effective date Extent of MTBE ban Arizona ...... January 1, 2005 ...... 0.3% max volume in gasoline. California ...... December 31, 2003 ...... complete ban in gasoline. Colorado ...... April 30, 2002 ...... complete ban in gasoline. Connecticut ...... January 1, 2004 ...... complete ban in gasoline. Illinois ...... July 24, 2004 ...... 0.5% max volume in gasoline. Indiana ...... July 24, 2004 ...... 0.5% max volume in gasoline. Iowa ...... July 1, 2000 ...... 0.5% max volume in gasoline. Kansas ...... July 1, 2004 ...... 0.5% max volume in gasoline. Kentucky ...... January 1, 2006 ...... 0.5% max volume in gasoline. Maine ...... January 1, 2007 ...... 0.5% max volume in gasoline. Michigan ...... June 1, 2003 ...... complete ban in gasoline. Minnesota ...... July 2, 2005 ...... complete ban in gasoline. (following partial ban in 2000). Missouri ...... July 1, 2005 ...... 0.5% max volume in gasoline. Montana ...... January 1, 2006 ...... no more than trace amounts in gasoline. Nebraska ...... July 13, 2000 ...... 1% max volume in gasoline. New Hampshire ...... January 1, 2007 ...... 0.5% max volume in gasoline. New Jersey ...... January 1, 2009 ...... 0.5% max volume in gasoline. New York ...... January 1, 2004 ...... complete ban in gasoline. North Carolina ...... January 1, 2008 ...... 0.5% max volume in gasoline. Ohio ...... July 1, 2005 ...... 0.5% max volume in gasoline. Rhode Island ...... June 1, 2007 ...... 0.5% max volume in gasoline. South Dakota ...... July 1, 2001 ...... 0.5% max volume in gasoline. Vermont ...... January 1, 2007 ...... 0.5% max volume in gasoline. Washington ...... January 1, 2004 ...... 0.6% max volume in gasoline. Wisconsin ...... August 1, 2004 ...... 0.5% max volume in gasoline. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00037 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS 24052 Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules C. Microbial Contaminants algae27), fresh water algae, and the whether sufficient information was 1. Evaluation of Microbial associated toxins available to determine whether current ≤ Contaminants for Regulatory TABLE 8.—INFORMATION GAPS FOR THE MICROBIAL CONTAMINANTS Analytical Health effects Treatment methods Occurrence Microsporidia ...... Aeromonas ...... Aeromonas ...... Aeromonas. Some Cyanotoxins ...... MAC ...... MAC ...... MAC. Adenoviruses ...... Helicobacter ...... Helicobacter. Caliciviruses ...... Microsporidia ...... Adenoviruses. Coxsackieviruses ...... Some Cyanotoxins ...... Caliciviruses. Echoviruses ...... Coxsackieviruses. Microsporidia ...... Echoviruses. Some Cyanotoxins ...... Microsporidia. Helicobacter ...... Some Cyanotoxins. 2. Research and Other Ongoing identification. For MAC, preliminary As an interim measure to assist public Activities. EPA has supported an active drinking water surveys have been water utilities, the Agency is planning research program to fill the information conducted using a culture method to develop an information sheet that gaps on the CCL 2 microorganisms. followed by genetic detection. EPA is discusses pertinent information on While several examples of the ongoing also conducting further research into cyanobacteria and some of its key research activities are listed below, methods development and the toxins. The document will discuss the further information on these and other characterization of virulence factors for state of the knowledge on the projects can be found on EPA’s Drinking this organism. prevention and treatment of Water Research Information Network cyanobacteria and its toxins, as well as EPA has funded projects to evaluate (DRINK). DRINK is a publicly- the available information on the the effect of disinfectants on accessible, Web-based system that tracks potential health effects of some of the cyanotoxins, and on the removal of algal over 1,000 ongoing research projects toxins. EPA requests comment from the cells and cyanotoxins in a pilot scale and can be accessed at: http:// public as to whether such a document www.epa.gov/safewater/drink/ treatment plant. EPA is developing would be useful for public water intro.html. analytical methods for potential use for utilities. a. Virus. For the CCL virus groups (or future monitoring and has available c. Protozoa. EPA has several ongoing surrogates), the Agency has initiated analytical chemistry standards for the projects to evaluate the susceptibility of treatment studies that simulate realistic toxins of most concern in the United microsporidia to chlorine and conditions where viruses may be States—microcystin, chloramine disinfectants. EPA has protected in aggregates. EPA also plans cylindrospermopsin, and anatoxin-a. sponsored methods-related projects for to conduct virus removal/inactivation EPA has conducted several small-scale microsporidia, which have included the studies in drinking water treatment preliminary occurrence surveys for use of fluorescent gene probes, real-time plants and/or pilot plants. In order to cyanotoxins using a screening method PCR, concentration methods, and assess the effectiveness of treatment and followed by confirmation by immunomagnetic separation. Ongoing to perform monitoring studies, methods instrumental analysis. A number of monitoring at EPA has revealed that development for viruses is also in health effects studies are also in microsporidia are present in ground progress. progress on several high priority water. EPA has funded work to b. Bacteria. For Aeromonas spp., EPA cyanotoxins. These include behavioral determine exposure to microsporidia, recently completed a one-year UCMR 1 studies in mice, acute and subacute and to determine strains (animal and survey of 293 public water systems. The effects in neonatal mice, and biomarkers human) of Enterocytozoon bieneusi Agency is currently attempting to of human exposure. Risk assessments found in water. EPA also held a characterize and distinguish pathogenic are being conducted at EPA on the workshop in 2003 on microsporidia to from non-pathogenic strains, as well as cyanotoxins to determine reference assess the state-of-the-science. develop methods to detect Aeromonas doses where possible. The Agency has virulence factors. For H. pylori, the organized and participated in several VII. EPA’s Next Steps Agency is in the process of developing workshops on cyanotoxins to assess the EPA intends to respond to the public a culture method and method for its state-of-the-science. comments it receives on the 11 27 Cyanobacteria are called blue-green algae even though they are technically bacteria. VerDate Mar 15 2010 08:52 Aug 04, 2010 Jkt 220001 PO 00000 Frm 00038 Fmt 4701 Sfmt 4702 E:\TEMP\01MYP2.LOC 01MYP2 rmajette on DSK29S0YB1PROD with MISCELLANEOUS Federal Register / Vol. 72, No. 83 / Tuesday, May 1, 2007 / Proposed Rules 24053 preliminary determinations and Men and Women Living in the United States. United States. Analysis of Relative Source subsequently issue its final regulatory Environmental Health Perspectives. Vol. 114, Contributions to the Food Chain. determinations. Although the No. 12. pp. 1865–1871. Environmental Science and Technology. Blount, B.C., L. Valent[iacute]n-Blasini, 40(21):6608–6614. preliminary determinations for all 11 J.D. Osterloh, J.P. Mauldin, and J.L. Pirkle. contaminants are not to regulate, if after Delzer, G.C. and T. Ivahnenko. 2003a. 2006c. Perchlorate Exposure of the U.S. Occurrence and Temporal Variability of consideration of public comments, the Population, 2001–2002. Journal of Exposure Methyl tert-Butyl Ether (MTBE) and Other Agency determines that a national Science and Environmental Epidemiology. Volatile Organic Compounds in Select primary drinking water regulation is Advance online publication 18 October 2006. Sources of Drinking Water: Results of the warranted for any of these 11 Available on the Internet at: http:// Focused Survey. U.S. Geological Survey www.nature.com/jes/journal/vaop/ncurrent/ contaminants, the regulation would Water-Resources Investigations Report 02– pdf/7500535a.pdf. then need to be formally proposed 4084, 65 p. Available on the Internet at: Blount, B.C., L. Valent[iacute]n-Blasini. within 24 months of the determination 2006. 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