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[Federal Register: April 3, 1996 (Volume 61, Number 65)] [Proposed Rules]
[Page 14696-14709]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 261[FRL-5448-4]
Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Proposed Exclusion
AGENCY: Environmental Protection Agency.
ACTION: Proposed rule and request for comment.
SUMMARY: The Environmental Protection Agency (EPA or Agency) today is proposing to grant a petition submitted by United Technologies Automotive (UTA), Detroit, Michigan, to exclude (or ``delist''), conditionally, on a one-time, upfront basis, a certain solid waste generated by UTA's chemical stabilization treatment of lagoon sludge at the Highway 61 Industrial Site in Memphis, Tennessee, from the lists of hazardous wastes in Secs. 261.31 and 261.32. Based on careful analyses of the waste-specific information provided by the petitioner, the Agency has concluded that UTA's petitioned waste will not adversely affect human health and the environment. This action responds to UTA's petition to delist this waste on a ``generator-specific'' basis from the hazardous waste lists. If the proposed decision is finalized, the petitioned waste will not be subject to regulation under Subtitle C of the Resource Conservation and Recovery Act (RCRA). The Agency is also proposing to use two methods to evaluate the potential impact of the petitioned waste on human health and the environment: (1) A fate and transport model (the EPA Composite Model for Landfills, ``EPACML'' model) , based on the waste-specific information provided by the petitioner; and (2) the generic delisting levels in Sec. 261.3(c)(2)(ii)(C)(1) for nonwastewater residues generated from treatment of the listed hazardous waste F006, by high temperature metal recovery (HTMR). Specifically, EPA proposes to use the EPACML model to calculate the concentration of each hazardous constituent that may be present in an extract of the petitioned waste obtained by means of the Toxicity Characteristic Leaching Procedure (TCLP), which will not have an adverse impact on groundwater if the petitioned waste is delisted and then disposed in a Subtitle D landfill. EPA will compare the concentration for each hazardous constituent calculated by the EPACML model to the generic delisting level for that constituent in Sec. 261.3(c)(2)(ii)(C)(1). EPA proposes to use the lower of these two concentrations as the delisting level for each hazardous constituent in the waste.
DATES: EPA is requesting public comments on this proposed decision and on the applicability of the fate and transport model and the generic delisting levels used to evaluate the petition. Comments will be accepted until May 20, 1996. Comments postmarked after the close of the comment period will be stamped ``late.'' Any person may request a hearing on this proposed decision by filing a request with Richard D. Green, Acting Director of the Waste Management Division, EPA, Region 4, whose address appears below, by April 18, 1996. The request must contain the information prescribed in Sec. 260.20(d).
ADDRESSES: Send three copies of your comments to Jeaneanne M. Gettle, Acting Chief, RCRA Compliance Section, U.S. Environmental Protection
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Agency, Region 4, 345 Courtland Street, NE., Atlanta, Georgia 30365. Identify your comments at the top with this regulatory docket number: R4-96-UTEP
Requests for a hearing should be addressed to Richard D. Green, Acting Director, Waste Management Division, U.S. Environmental Protection Agency, Region 4, 345 Courtland Street, NE., Atlanta, Georgia 30365.
The RCRA regulatory docket for this proposed rule is located at the EPA Library, U.S. Environmental Protection Agency, Region 4, 345 Courtland Street, N.E., Atlanta, Georgia 30365, and is available for viewing from 9:00 a.m. to 4:00 p.m., Monday through Friday, excluding Federal holidays.
The public may copy material from any regulatory docket at no cost for the first 100 pages, and at a cost of $0.15 per page for additional copies.
Copies of the petition are available during normal business hours at the following addresses for inspection and copying: Tennessee Department of Environment and Conservation, 5th Floor, L & C Tower, 401 Church Street, Nashville, Tennessee 37243-1535; and U.S. EPA Region 4, Library, 345 Courtland Street, NE., Atlanta, Georgia 30365; (404) 347- 4216.FOR FURTHER INFORMATION CONTACT: For general information, contact the RCRA Hotline, toll free at (800) 424-9346, or at (703) 412-9810. For technical information concerning this notice, contact Judy Sophianopoulos, RCRA Compliance Section, (Mail Code 4WD-RCRA), U.S. Environmental Protection Agency, Region 4, 345 Courtland Street, NE., Atlanta, Georgia 30365, (404) 347-3555, x6408, or call, toll free, (800) 241-1754, and leave a message, with your name and phone number, for Ms. Sophianopoulos to return your call. You may also contact Jerry Ingram, Tennessee Department of Environment and Conservation, 5th Floor, L & C Tower, 401 Church Street, Nashville, Tennessee 37243-1535, (615) 532-0850.
SUPPLEMENTARY INFORMATION:
I. Background
A. Authority
On January 16, 1981, as part of its final and interim final regulations implementing Section 3001 of RCRA, EPA published an amended list of hazardous wastes from non-specific and specific sources. This list has been amended several times, and is published in Secs. 261.31 and 261.32. These wastes are listed as hazardous because they exhibit one or more of the characteristics of hazardous wastes identified in Subpart C of part 261 (i.e., ignitability, corrosivity, reactivity, and toxicity) or meet the criteria for listing contained in Sec. 261.11 (a)(2) or (a)(3).
Individual waste streams may vary, however, depending on raw materials, industrial processes, and other factors. Thus, while a waste that is described in these regulations generally is hazardous, a specific waste from an individual facility meeting the listing description may not be. For this reason, Secs. 260.20 and 260.22 provide an exclusion procedure, allowing persons to demonstrate that a specific waste from a particular generating facility should not be regulated as a hazardous waste.
To have their wastes excluded, petitioners must show, first, that wastes generated at their facilities do not meet any of the criteria for which the wastes were listed. See Sec. 260.22(a) and the background documents for the listed wastes. Second, the Administrator must determine, where he/she has a reasonable basis to believe that factors (including additional constituents) other than those for which the waste was listed could cause the waste to be a hazardous waste, that such factors do not warrant retaining the waste as a hazardous waste. Accordingly, a petitioner also must demonstrate that the waste does not exhibit any of the hazardous waste characteristics (i.e., ignitability, reactivity, corrosivity, and toxicity), and must present sufficient information for the Agency to determine whether the waste contains any other toxicants at hazardous levels. See Sec. 260.22(a), 42 U.S.C. Sec. 6921(f), and the background documents for the listed wastes. Although wastes which are ``delisted'' (i.e., excluded) have been evaluated to determine whether or not they exhibit any of the characteristics of hazardous waste, generators remain obligated under RCRA to determine whether or not their wastes continue to be nonhazardous based on the hazardous waste characteristics (i.e., characteristics which may be promulgated subsequent to a delisting decision.)
In addition, residues from the treatment, storage, or disposal of listed hazardous wastes and mixtures containing listed hazardous wastes are also considered hazardous wastes. See Secs. 261.3(a)(2)(iv) and (c)(2)(i), referred to as the ``mixture'' and ``derived-from'' rules, respectively. Such wastes are also eligible for exclusion and remain hazardous wastes until excluded. On December 6, 1991, the U.S. Court of Appeals for the District of Columbia vacated the ``mixture/derivedfrom'' rules and remanded them to the Agency on procedural grounds. Shell Oil Co. v. EPA, 950 F.2d 741 (D.C. Cir. 1991). On March 3, 1992, EPA reinstated the mixture and derived-from rules, and solicited comments on other ways to regulate waste mixtures and residues (57 FR 7628, Mar. 3, 1992). The Agency plans to address issues related to waste mixtures and residues in a future rulemaking. On October 10, 1995, the Administrator delegated to the Regional Administrators the authority to evaluate and approve or deny petitions submitted in accordance with Secs. 260.20 and 260.22, by generators within their Regions [National Delegation of Authority 8-19], in States not yet authorized to administer a delisting program in lieu of the Federal program. On March 11, 1996, the Regional Administrator of EPA, Region 4, redelegated delisting authority to the Director of the Waste Management Division [Regional Delegation of Authority 8-19].B. Approach Used To Evaluate This Petition
This petition requests a delisting for a hazardous waste listed as F006. In making the initial delisting determination, the Agency evaluated the petitioned waste against the listing criteria and factors cited in Secs. 261.11 (a)(2) and (a)(3). Based on this review, the Agency agrees with the petitioner that the waste is nonhazardous with respect to the original listing criteria. (If the Agency had found, based on this review, that the waste remained hazardous based on the factors for which the waste was originally listed, EPA would have proposed to deny the petition.) EPA then evaluated the waste with respect to other factors or criteria to assess whether there is a reasonable basis to believe that such additional factors could cause the waste to be hazardous. See Secs. 260.22 (a) and (d). The Agency considered whether the waste is acutely toxic, and considered the toxicity of the constituents, the concentration of the constituents in the waste, their tendency to migrate and to bioaccumulate, their persistence in the environment once released from the waste, plausible and specific types of management of the petitioned waste, the quantities of waste generated, and waste variability. For this delisting determination, the Agency used such information to identify plausible exposure routes (i.e., groundwater, surface water, air) for hazardous constituents present in the petitioned waste. The Agency determined that disposal in a Subtitle D landfill is the most reasonable, worst-case disposal scenario for UTA's petitioned waste, and that the major exposure route of concern would be
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ingestion of contaminated groundwater. Therefore, the Agency is proposing to use a particular fate and transport model (the ``EPACML'' model) to predict the maximum allowable concentrations of hazardous constituents that may be released from the petitioned waste after disposal and to determine the potential impact of the disposal of UTA's petitioned waste on human health and the environment. Specifically, the Agency used the maximum estimated waste volume and the maximum reported leachate concentrations as inputs to estimate the constituent concentrations in the groundwater at a hypothetical receptor well downgradient from the disposal site. The calculated receptor well concentrations (referred to as compliance-point concentrations) were then compared directly to the health-based levels used in delisting decision-making for the hazardous constituents of concern.
EPA believes that this fate and transport model represents a reasonable worst-case scenario for disposal of the petitioned waste in a landfill, and that a reasonable worst-case scenario is appropriate when evaluating whether a waste should be relieved of the protective management constraints of RCRA Subtitle C. The use of a reasonable worst-case scenario results in conservative values for the compliancepoint concentrations and ensures that the waste, once removed from hazardous waste regulation, will not pose a threat to human health or the environment. Because a delisted waste is no longer subject to hazardous waste control, the Agency is generally unable to predict and does not control how a waste will be managed after delisting. Therefore, EPA currently believes that it is inappropriate to consider extensive site-specific factors when applying the fate and transport model.
For example, a generator may petition the Agency for delisting of a metal hydroxide sludge which is currently being managed in an on-site landfill and provide site-specific data, such as the nearest drinking water well, permeability of the aquifer, and dispersivities. If the Agency were to base its evaluation solely on these site-specific factors, the Agency might conclude that the waste, at that specific location, cannot affect the closest well, and the Agency might grant the petition. Upon promulgation of the exclusion, however, the generator is under no obligation to continue to manage the waste at the on-site landfill. In fact, the generator may well choose to either send the delisted waste off site immediately, or eventually reach the capacity of the on-site facility and subsequently send the waste off site to a facility which may have very different hydrogeological and exposure conditions.
The Agency also considers the applicability of groundwater monitoring data during the evaluation of delisting petitions. In this case, the Agency determined that, because UTA is seeking a delisting for treated lagoon wastes which will be generated during a removal action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), and may be managed ultimately either on site or off site, groundwater monitoring data collected from the areas where the petitioned waste is contained prior to treatment, are necessary to determine whether hazardous constituents have already migrated to the underlying groundwater. Groundwater monitoring data collected from UTA's monitoring wells will help characterize the potential impact (if any) of the disposal of UTA's waste on human health and the environment.
UTA petitioned the Agency for an upfront, conditional, one-time exclusion based on analytical data on samples from a treatability study and on samples of untreated waste. Similar to other facilities seeking upfront exclusions, this upfront exclusion would be contingent upon UTA conducting analytical testing of representative samples of the petitioned waste as soon as the treatment system is brought on-line. This testing would be necessary to demonstrate that the treated waste is a nonhazardous waste (i.e., meets the Agency's verification testing conditions).
From the evaluation of UTA's delisting petition, a list of constituents was developed for the verification testing conditions. Proposed maximum allowable leachable concentrations for these constituents, and a total concentration for one, were derived as described in Section II.D. and Section II.E. of this preamble. The Agency encourages the use of upfront delisting petitions because they have the advantage of allowing the applicant to know what treatment levels for constituents will be sufficient to render specific wastes nonhazardous, before investing in new or modified waste treatment systems. Therefore, upfront delistngs will allow new facilities to receive exclusions prior to generating wastes, which, without upfront exclusions would unnecessarily have been considered hazardous. Upfront delistings for existing facilities can be processed concurrently during construction or permitting activities; therefore, new or modified treatment systems should be capable of producing wastes that are considered nonhazardous sooner than would otherwise be possible. At the same time, conditional testing requirements to verify that the delisting levels are achieved by the fully operational treatment systems will ensure that only nonhazardous wastes are removed from Subtitle C control.
In the past, the Agency has granted numerous conditional delistings, including conditional delistings for waste treatment facilities located at multiple sites (see 51 FR 41323, November 14, 1986, and 51 FR 41494, November 17, 1986), as well as an upfront delisting that allows an additional treatment unit to be added at the same site (see 56 FR 32993, July 18, 1991), and an upfront delisting that allows new treatment units at different sites to be added, provided the verification testing conditions are satisfied (see 60 FR 31107, June 13, 1995).
The Agency provides notice and an opportunity for comment before granting or denying a final exclusion. Thus, a final decision will not be made until all timely public comments (including those at public hearings, if any) on today's proposal are addressed. Late comments will be considered to the extent possible.II. Disposition of Delisting Petition United Technologies Automotive, Detroit, Michigan
A. Petition for Exclusion
United Technologies Automotive (UTA), located in Detroit, Michigan, is seeking a delisting for treated lagoon waste which will be generated during a removal action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The removal action is required by the Unilateral Administrative Order (``the UAO'') issued to UTA by EPA, on January 26, 1995. The waste to be treated was generated prior to 1980 in seven lagoons formerly used to manage electroplating wastewater at the Highway 61 Industrial Site in Memphis, Tennessee (``the Site''). Notwithstanding the fact that the waste was generated prior to 1980, the waste so generated meets the listing definition of EPA Hazardous Waste No. F006--``Wastewater treatment sludges from electroplating operations except from the following processes: (1) Sulfuric acid anodizing of aluminum; (2) tin plating on carbon steel; (3) zinc plating (segregated basis) on carbon steel; (4) aluminum or zinc-aluminum
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plating on carbon steel; (5) cleaning/stripping associated with tin, zinc, and aluminum plating on carbon steel; and (6) chemical etching and milling of aluminum''--when it is actively managed by excavation and treatment after the effective date of the listing of F006. (Original listing of F006 by Interim Final Rule in 45 FR 33112-33133, May 19, 1980; Modified in 45 FR 74384-74892, Nov. 12, 1980; and clarified by Interpretative Rule in 51 FR 43350-43351, Dec. 2, 1986). See 51 FR 40577, Nov. 7, 1986; 53 FR 31147-31148, Aug. 17, 1988; 53 FR 51444 and 51445, Dec. 21, 1988; 55 FR 22678, June 1, 1990; and Chemical Waste Management v. EPA, 869 F.2d at 1535-37 (D.C. Cir. 1989), for Agency position on active management. UTA proposes to treat the sludge by chemical stabilization, and to delist the treatment residue, which is also classified as F006 by application of Sec. 261.3(c)(2)(i), the derived-from rule. By application of the ``contained-in policy,'' any lagoon soil excavated and treated with the sludge must also be managed as F006. See memorandum, dated February 17, 1995, from Devereaux Barnes to Norm Niedergang, and Region 4 Guidance Number TSC-92-02, dated August 1992.
UTA petitioned the Administrator, in October 1995, to exclude, on a one-time, upfront basis, the treatment residue generated from chemical stabilization of sludges removed from six of the seven lagoons located at the Site. Sludges from Lagoon 7 will not be removed and treated, because constituent concentrations were found, by total analysis of these samples, to be below the cleanup levels required by the UAO. On November 21, 1995, in accordance with the delegation of delisting authority by the Administrator to the Regional Administrators, UTA submitted to EPA, Region 4, the petition to delist F006 generated by chemical stabilization of sludges from the six lagoons at the Site. The hazardous constituents of concern for which F006 was listed are cadmium, hexavalent chromium, nickel, and cyanide (complexed). Chemically stabilized sludge and soil from the six lagoons at the Site is the waste which is the subject of this petition. UTA petitioned the Agency to exclude its waste because it does not believe that the waste meets the criteria of the listing.
UTA claims that its chemically stabilized sludge/soil is not hazardous because the constituents of concern, although present in the waste, are present in either insignificant concentrations or, if present at significant levels, are essentially in immobile forms. UTA also believes that this waste is not hazardous for any other reason (i.e., there are no additional constituents or factors that could cause the waste to be hazardous). Review of this petition included consideration of the original listing criteria, as well as the additional factors required by the Hazardous and Solid Waste Amendments (HSWA) of 1984. See Section 222 of HSWA, 42 USC 6921(f), and 40 CFR 260.22(d)(2)-(4). Today's proposal to grant this petition for delisting is the result of the Agency's evaluation of UTA's petition.B. Background
On November 21, 1995, UTA petitioned EPA, Region 4, to exclude the chemically stabilized sludge and soil from Lagoons 1-6 at the Highway 61 Industrial Site in Memphis, Tennessee (``the Site''), and subsequently provided additional information, in response to a request by EPA. After evaluating the petition and the additional information, the Agency proposes to approve UTA's petition to exclude the subject waste, because the Agency believes that the petitioned waste is eligible for an exclusion based on the current evaluation criteria. Therefore, the Agency hereby proposes to grant UTA's petition. The Agency's evaluation of UTA's petitioned waste, which consists of the chemically stabilized sludge and soil from Lagoons 1-6 at the Site, is the subject of today's proposal.
In support of its petition, UTA submitted: (1) detailed descriptions of the waste and history of its management; (2) detailed descriptions of all previously known and current activities at the Site; (3) results from total constituent analyses for arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver, (the eight Toxicity Characteristic (TC) metals listed in Sec. 261.24); the priority pollutant metals, including nickel, (a hazardous constituent for which F006 is listed), antimony,and thallium; and cyanide; (4) results for the eight Toxicity Characteristic (TC) metals from the Toxicity Characteristic Leaching Procedure (TCLP; Method 1311 in ``Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,'' EPA Publication SW-846 [Third Edition (November 1986), as amended by Updates I (July 1992), II (September 1994), IIA (August 1993), and IIB (January 1995)]; methods in this publication are referred to in today's proposed rule as ``SW-846,'' followed by the appropriate method number); (5) results from the Multiple Extraction Procedure (MEP; SW- 846 Method 1320) for cadmium and chromium; (6) results from the analysis for total petroleum hydrocarbons (TPH, Method 418.1 in ``Methods for Chemical Analysis of Water and Wastes,'' EPA Publication EPA-600/4-79-020; (7) results from characteristics testing for ignitability, corrosivity, and reactivity; (8) results from total constituent analyses for 33 volatile organic compounds and 64 semivolatile organic constituents, including the TC organic constituents; and (9) groundwater monitoring data collected from wells monitoring the on-site lagoons.
UTA's petition states that electroplating operations at the Site were conducted between the early 1960s and 1973, and no electroplating wastewater sludge was generated after 1973. Lagoons 1-7 contained electroplating wastewaters and were allegedly used for oxidation purposes. UTA reported that the sludge generated in the lagoons has a moisture content of approximately 56
A CERCLA Unilateral Administrative Order issued on January 26, 1995 (``the UAO''), required that sludge from lagoons at the Site be excavated, stabilized, and disposed of, as part of an emergency removal action. UTA estimates that the total volume of the chemically stabilized sludge and soil from Lagoons 1-6 at the Site will be 11,500 cubic yards. (Site Lagoon 7 met the cleanup standards of the UAO, and did not require removal.)
The UAO required UTA to develop a Removal Action Work Plan Sampling Protocol. EPA approved the Removal Action Work Plan, including the Sampling Protocol, on March 30, 1995. UTA's sampling and analysis methods were conducted in accordance with the approved Removal Action Work Plan.
UTA's sampling demonstration included data on 225 samples of untreated waste from Lagoons 1-7, collected in April 1995, and 4 samples of treated waste from Lagoons 1-6, collected in September 1995. UTA conducted sampling and analysis of the seven Site lagoons, ranging in size from approximately \1/4\-1 acre, in accordance with the Sampling Protocol of the Removal Action Work Plan required by the UAO. Each lagoon was divided into a minimum of 4 quadrants; grab samples of sludge or soil in each quadrant to be analyzed for all constituents except volatile organic compounds (VOCs), were composited. VOC analysis was performed on a minimum of two grab samples per lagoon. A total of 225 samples were collected and analyzed. The sampling and analysis were performed in order to obtain representative samples of each[[Page 14700]]
lagoon and determine whether the following Site soil removal cleanup levels required by the UAO were met; areas not meeting these levels were subject to the removal action:Table 1.--Site Cleanup Levels
Cleanup level, parts Parameter per million (ppm)
Total Petroleum Hydrocarbons (TPH)............................. 100 Cadmium (total)................................................ 60 Chromium (total)............................................... 400 Chromium VI.................................................... 205Lead........................................................... 500
With the exception of total petroleum hydrocarbons (TPH), all contaminants in treated and untreated waste were analyzed using SW-846 methods. All composite samples of untreated wastes were analyzed for TPH, using Method 418.1, in ``Methods for Chemical Analysis of Water and Wastes,'' EPA Publication EPA-600/4-79-020). All composite samples of untreated wastes were analyzed for 64 semivolatile organic compounds (SVOCs), otherwise known as base-neutral or acid extractables (BNAs, SW-846 extraction Method 3550, SW-846 analysis Method 8270); and the eight RCRA TC metals, arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver (SW-846 Method 6010 for all except mercury; SW-846 Method 7471 for mercury). One composite sample of untreated waste from each lagoon, except Lagoon 1 and Lagoon 3, was analyzed for metals on the Target Analyte List (TAL) (SW-846 Method 6010), which includes aluminum, antimony, beryllium, calcium, cobalt, copper, iron, magnesium, manganese, nickel, potassium, sodium, thallium, vanadium, and zinc, in addition to the RCRA TC metals. These metals are also referred to as ``priority pollutant metals,'' regulated under the Clean Water Act and the Safe Drinking Water Act. Toxic TAL metals antimony, beryllium, and thallium, and RCRA TC metals mercury, selenium, and silver were not detected in the untreated waste samples above the quantitation limits of 10.0, 1.0, 1.0, 0.09, 1.0 and 1.0 mg/kg, respectively. The concentrations of all metals which were detected in the untreated waste, except for cadmium and chromium, were low enough that the UAO did not set cleanup levels for them. Concentrations of metals which were detected in untreated wastes are presented in Table 2. SVOCs were undetected in most of the untreated waste samples at quantitation limits ranging from 0.33-0.83 mg/kg. Table 2 shows the SVOCs that were detected in untreated waste samples; their concentrations were low enough that the UAO did not require cleanup levels for them. At least two grab samples of untreated waste from each lagoon were analyzed for 33 VOCs by SW-846 Method 8240; these VOCs were not detected in most of the samples of untreated waste at quantitation limits ranging from 0.005-0.010 mg/kg. The VOCs detected in untreated waste are shown in Table 2. The concentrations detected in the untreated waste were low enough that the UAO did not establish cleanup levels for VOCs.
All of the analyses summarized in the preceding paragraph are methods for total analysis of the samples; that is, the samples were subjected to the appropriate SW-846 method without prior extraction by means of the Toxicity Characteristic Leaching Procedure (TCLP). The analytical result obtained in a total analysis is the concentration of contaminant on a weight/weight basis, in units of milligrams of contaminant per kilogram of sample (mg/kg). The result of a TCLP analysis is the concentration of contaminant on a weight/volume basis in an extract of the sample obtained by means of the TCLP, in units of milligrams of contaminant per liter of TCLP extract. The RCRA TC metals cadmium and total chromium were analyzed in all composite samples of untreated waste using SW-846 Method 6010, with a reported quantitation limit (total analysis on unextracted sample) of 1.0 mg/kg for each. Results are presented in Table 2. A total analysis for hexavalent chromium was conducted on all samples (both composite and grab) of untreated waste (SW-846 Method 7197), and was not detected in any of the samples, at a quantitation limit of 10.0 mg/kg. Therefore, UTA concluded that the total chromium concentrations in the untreated lagoon samples were due to trivalent chromium. Based on the analytical results for the untreated waste samples, UTA identified cadmium, trivalent chromium, and TPH as the only constituents of concern in the Site lagoons, because these were the only constituents found with concentrations above the cleanup levels required by the UAO. TCLP extracts of two samples of untreated waste from Lagoon 6 were prepared and analyzed, because constituent concentrations by total analysis (analysis of the unextracted samples) exceeded the cleanup levels required by the UAO, to a greater extent than any of the other samples. TCLP results for untreated waste samples from Lagoon 6, as well as total analysis results for untreated waste samples from all lagoons, are presented in Table 2.Table 2.--Concentrations in Untreated Samples From Site Lagoons 1 Through 7 Maximum concentration \1\ in lagoons 1-7: (total analysis in mg/kg; TCLP in mg/l) Constituent ------------------------------------------------------------------------------------------------- Lagoon Lagoon Lagoon Lagoon Lagoon Lagoon Lagoon 1 2 3 4 5 6 7
Arsenic (total)....................................... 3.1 4.5 4.5 4.1 4.7 3.0 4.6 Barium (total)........................................ 144 79.3 91.6 89.5 71.2 370 71.5 Cadmium (total)....................................... 1010 345 383 239 141 1590 11.2 Cadmium (TCLP)........................................ NA NA NA NA NA 26.0 ............ Chromium (total)...................................... 1320 219 578 345 292 943 13.1 Chromium (TCLP)....................................... NA NA NA NA NA <0.50 ............ Lead (total).......................................... 19.5 10.10 25.9 9.0 9.5 26.2 17.9 Nickel (total)........................................ ............ 12 ............ 10.2 8.7 7.0 13.1 TPH (total)........................................... 440 217 278 100 58.7 272 52.7 Acetone (total)....................................... 0.492 -- 0.482 0.219 3.07 4.54 0.556 Bis(2-ethylhexyl) phthalate (total)................... 0.47 -- 1.37 1.40 -- 0.77 -- Chlorobenzene (total)................................. 0.015 -- 0.078 -- -- -- -- Di-n-butylphthalate (total)........................... -- -- -- 0.63 -- -- --[[Page 14701]]
1,2-dichloroethene (total)............................ 0.020 0.060 0.020 -- 0.007 -- -- Vinyl chloride (total)................................ 0.015 0.055 -- -- -- -- -- \1\ The concentration level for each constituent in each lagoon in Table 2 is the maximum found for that lagoon; the values for each lagoon are not necessarily from the same sample. Frequently, a sample with a maximum concentration level for one constituent did not contain maximum levels for allconstituents. < denotes undetected at the practical quantitation limit, the number to the right of the symbol <. NA means not analyzed. --Denotes analyzed but not detected.UTA reported that one sample of untreated waste from each lagoon was tested for the hazardous characteristics of corrosivity, ignitability, and reactivity for cyanide and sulfide, and that none of the samples exhibited these hazardous characteristics. UTA conducted a treatability study on samples of lagoon sludge in order to determine the optimum conditions for chemical stabilization. UTA found that the most effective chemical stabilization recipe to achieve maximum immobilization of cadmium and chromium and maxium compressive strength in the petitioned waste was 20 10me kiln dust (LKD) and 5aortland cement (PC). Treatability study samples #32 and #36 were composite sludge samples from Lagoons 1 through 6, and were chemically stabilized with two different recipes. Sample #32 was stabilized with 20KD only, and sample #36 was stabilized with 20 LKD and 5PC. Samples #6-32 and #6-36 were composite samples from Lagoon 6, the most contaminated lagoon. Sample #6-32 was chemically stabilized with 20KD only, and sample #6-36 was chemically stabilized with 20KD and 5PC. UTA reported that, prior to treatment, samples #32, #36, #6-32, #6-36 were subjected to total analysis for cadmium and chromium (SW-846 Method 6010). After treatment, SW-846 Method 6010 was performed on TCLP extracts of treated samples to determine concentrations of cadmium and chromium in the extracts. Total analysis for 33 VOCs was performed on treated samples (not on TCLP extracts), using SW-846 Method 8240. VOCs were not detected in any of the samples of treated waste at quantitation limits ranging from 0.005-0.010 mg/kg. Analytical results for treatability study samples are shown in Table 3. UTA informed EPA during a meeting on December 13, 1995, that these analytical results are for chemically stabilized, but not fully cured, waste samples. Samples from Lagoon 7 were not included in the treatability study, because constituent concentrations were found, by total analysis of these samples, to be below the cleanup levels required by the UAO. Therefore, the UAO does not require removal of Lagoon 7 sludge and soil. UTA believes that the treatability study of chemical stabilization of the lagoon waste indicated that cadmium and chromium concentrations in the TCLP extracts were reduced to levels which would meet delisting criteria, and that TPH constituents were removed in the offgas from the chemical stabilization process.
If UTA's delisting petition is approved, UTA proposes to dispose of the delisted waste either (a) onsite in accordance with a Closure/PostClosure Plan approved by the State of Tennessee or (b) in an off-site Subtitle D landfill. Therefore, UTA subjected treatability study samples #32 and #36, after treatment, to the Multiple Extraction Procedure (MEP). The MEP (SW-846 Method 1320) is a test developed by the Agency to assist in predicting the long-term leachability of stabilized wastes. The MEP consists of a TCLP extraction of a sample followed by nine sequential extractions of the same sample, using a synthetic acid rain extraction fluid (prepared by adding a 60/40 weight mixture of sulfuric acid and nitric acid to distilled deionized water until the pH is 3.0 <plus-minus> 0.2). The sample which is subjected to the nine sequential extractions consists of the solid phase remaining after, and separated from, the initial TCLP extract. The Agency designed the MEP to simulate multiple washings of percolating rainfall in the field, and estimates that these extractions simulate approximately 1,000 years of rainfall. (See 47 FR 52687, Nov. 22, 1982.) MEP results for samples #32 and #36 are presented in Table 3. In response to a request by EPA for additional information, UTA reported a quantitation limit of 0.01 mg/l for cadmium and chromium in the MEP test on samples #32 and #36. Samples #32, #36, #6-32, and #6-36 were also tested by the synthetic precipitation leaching procedure (SPLP, SW-846 Method 1312), which consists of a single extraction by the same synthetic acid rain solution used in the MEP. Total analysis, TCLP, SPLP, and MEP results for stabilized, but not fully cured, treatability study samples are presented in Table 3.Table 3.--Analytical Results (ppm) for Treated Samples of Site Lagoon Sludge [Chemically Stabilized, But Not Fully Cured]
Totals (untreated) TCLP (treated) SPLP (treated) Multiple extraction procedure (treated) ------------------------------------------------------------------------------------------------------------- Maximum conc./ Concentration in Sample \1\ Cadmium Chromium extract number final extract (Cd) (Cr) Cd Cr Cr Cr ------------------------------------------- Cd Cr Cd Cr
36........................................ 543 449 <0.10 <0.50 <0.01 0.07 0.56/6 0.07/1 0.03 0.02 6-36...................................... 777 289 <0.10 <0.50 ......... ......... ......... ......... ......... ......... 32........................................ 543 449 <0.10 <0.50 <0.01 0.04 0.80/6 0.06/7 0.05 0.03[[Page 14702]]
6-32...................................... 777 289 <0.10 <0.50 ......... ......... ......... ......... ......... .........
\1\ Sample 36 (composite of Lagoons 1-6) was stabilized with 20 10me kiln dust (LKD) and 567ortland cement (PC); Sample 6-36 (composite from Lagoon 6) was stabilized with 20KD and 5PC; Sample 32 (composite of Lagoons 1-6) was stabilized with 20KD only; Sample 6-32 (composite from Lagoon 6)was stabilized with 20KD only. < Denotes that the constituent was not detected above the practical quantitation limit, the number to the right of the symbol <.UTA included Site groundwater monitoring data in its delisting petition, because disposal option (a) above involves onsite disposal of the treated waste. These data are shown in Table 4, and were obtained by sampling 5 groundwater monitoring wells which had been installed to assess the impact of untreated lagoon waste on Site groundwater. The wells were installed upgradient, cross-gradient, and downgradient to the Site lagoons in accordance with the Removal Action Work Plan required by the UAO. The wells were sampled and analyzed for cadmium and chromium in July 1995.
Table 4.--Groundwater Result Summary (ppm) Untreated Lagoon Waste
State of Constituent MW-1 MW-2 MW-3 MW-4 MW-5 Tennessee Federal MCL MCL
Cadmium..................................................... <0.005 <0.005 <0.005 <0.005 <0.005 0.01 0.005 Chromium.................................................... 0.010 <0.010 0.011 <0.010 <0.010 0.05 0.10
< Denotes that the constituent was not detected above the practical quantitation limit, the number to the right of the symbol <. Monitoring wells are numbered consecutively MW-1--MW-5.MCL is the maximum contaminant level allowable in drinking water, as established by the Safe Drinking Water Act; MCLs for the State of Tennessee are thelevels adopted by State law.UTA believes that the groundwater results summarized in Table 4 indicate that land disposal of chemically stabilized waste from Site Lagoons 1-6 will not have an adverse impact on groundwater quality, because UTA believes that the data in Table 4 demonstrate that the untreated lagoon waste has not adversely affected groundwater quality. In addition to the data in Table 4, the groundwater monitoring information submitted by UTA also included: (1) Well location information; and (2) water level contour maps. EPA does not generally verify submitted test data before proposing delisting decisions. The sworn affidavit submitted with this petition binds the petitioner to present truthful and accurate results. The Agency, however, has maintained a spot-check sampling and analysis program to verify the representative nature of data for some percentage of the submitted petitions. A spot-check visit to a selected facility may be initiated before finalizing a delisting petition or after granting an exclusion.
The Agency reviews a petitioner's estimates and, on occasion, has requested a petitioner to re-evaluate estimated waste volume. EPA accepts UTA's estimate of 11,500 cubic yards.D. Agency Evaluation
The Agency considered the appropriateness of alternative waste management scenarios for UTA's chemically stabilized sludge and soil and decided, based on the information provided in the petition, that disposal in a Subtitle D landfill is the most reasonable, worst-case scenario for this waste. Under a landfill disposal scenario, the major exposure route of concern for any hazardous constituents would be ingestion of contaminated groundwater. The Agency, therefore, evaluated UTA's petitioned waste using the EPA's Composite Model for Landfills (EPACML), as modified for delisting evaluations, which predicts the potential for groundwater contamination from wastes that are landfilled. For metal constituents in 40 CFR 261.3(c)(2)(ii)(C)(1), EPA also evaluated UTA's petitioned waste by comparing generic delisting levels in Sec. 261.3(c)(2)(ii)(C)(1) with EPACML levels. See 60 FR 31108-31115, June 13, 1995, a Final Rule in which EPA evaluated a petition and approved an exclusion based on comparing these generic delisting levels with EPACML levels, and selecting the generic delisting levels if they were lower than the levels generated from the EPACML model. The EPACML model is more sophisticated than the Vertical Horizontal Spread (VHS) model used previously by the Agency for evaluating delisting petitions. See 56 FR 32993, July 18, 1991; and 56 FR 67197, Dec. 30, 1991 for a detailed description of the EPACML model, the disposal assumptions, the modifications made for delisting, and the benefits of replacing the VHS model with the EPACML model for delisting. This model, which includes both unsaturated and saturated zone transport modules, was used to predict reasonable worst-case contaminant levels in groundwater at a compliance point (i.e., a receptor well serving as a drinking-water supply). Specifically, the model estimated the dilution/attenuation factor (DAF) resulting from subsurface processes such as three-dimensional dispersion and dilution from groundwater recharge for a specific volume of waste. The Agency requests public comments on its use of the EPACML model and generic delisting levels in Sec. 261.3(c)(2)(ii)(C)(1) as applied to the evaluation of UTA's waste. EPA will
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consider all comments on the validity of the EPACML model and generic delisting levels in Sec. 261.3(c)(2)(ii)(C)(1) and the appropriateness for their use here to evaluate the potential for groundwater contamination if UTA's petitioned waste is disposed of in any Subtitle D landfill.
For the evaluation of UTA's petitioned waste, the Agency used the EPACML model to evaluate the mobility of hazardous inorganic constituents detected in the extract of samples of UTA's petitioned waste. The Agency's evaluation, using UTA's estimated one-time waste volume of 11,500 cubic yards and the EPACML modified for delisting yielded a dilution/attenuation factor (DAF) of 100. See Table 5, which is a list of DAFs calculated by the EPACML model, modified for delisting, for landfills receiving different annual volumes of waste. The DAFs in Table 5 include a scaling factor of 20, because the average life of a subtitle D landfill is 20 years and the typical delisting petition is for continuously generated waste which is sent to a landfill at a certain annual rate. That annual rate, the volume of waste in cubic yards per year, can be converted to a landfill size for input into the EPACML model to generate a DAF, with the assumption that the annual rate supplied by the delisting petitioner is multiplied by 20 prior to the conversion. The Agency has completed these calculations for a range of annual waste volumes and they are summarized in Table 5. The Agency need not use the scaling factor of 20 for a petitioned onetime exclusion. Therefore, instead of a DAF of 34 obtained from Table 5 for 11,500 cubic yards, the Agency could eliminate the scaling factor of 20 by dividing 11,500 cubic yards by 20, thereby obtaining a waste volume of 575 and the maximum possible DAF of 100 in Table 5. See 55 FR 11826, March 29, 1990; 56 FR 32993, July 18, 1991; and 56 FR 67197, Dec. 30, 1991 for a detailed description of the EPACML model, the disposal assumptions, and the modifications made for delisting. See also 60 FR 62801, Dec. 7, 1995, for a previous delisting proposal in which the Agency obtained a DAF of 48, instead of 14.8, from a table containing the same landfill DAFs and waste volumes as Table 5, for a one-time exclusion of a volume of waste equal to 110,000 cubic yards. (See docket for this rule for further details on the use of the EPACML model in evaluating UTA's waste.)Table 5.--Dilution/Attenuation Factors (DAFs) for Landfills Calculated by the EPACML Model, Modified for Delisting
DAF (95thWaste volume in cubic yards per year \1\ percentile) ----------------------------------------------------------------\2\----- 1,000................................................... \3\ 100 1,250................................................... 96 1,500................................................... 90 1,750................................................... 84 2,000................................................... 79 2,500................................................... 74 3,000................................................... 68 4,000................................................... 57 5,000................................................... 54 6,000................................................... 48 7,000................................................... 45 8,000................................................... 43 9,000................................................... 40 10,000.................................................. 36 12,500.................................................. 33 15,000.................................................. 29 20,000.................................................. 27 25,000.................................................. 24 30,000.................................................. 23 40,000.................................................. 20 50,000.................................................. 19 60,000.................................................. 17 80,000.................................................. 17 90,000.................................................. 16 100,000................................................. 15 150,000................................................. 14 200,000................................................. 13 250,000................................................. 12 300,000................................................. 12
\1\ The waste volume includes a scaling factor of 20; see 56 FR 32993, July 18, 1991; and 56 FR 67197, Dec. 30, 1991, and text of today's proposed rule, for a discussion of the use of the scaling factor. \2\ The DAFs calculated by the EPACML are a probability distribution based on a range of values for each model input parameter; the input parameters include such variables as landfill size, climatic data, and hydrogeologic data. The 95th percentile DAF represents a value in which one can have 95
onfidence that a contaminant's concentration will be reduced by a factor equal to the DAF, as the contaminant moves from the bottom of the landfill through the subsurface environment to a receptor well. For example, if the 95th percentile DAF is 10, and the leachate concentration of cadmium at the bottom of the landfill is 0.05 mg/l, one can be 95
onfident that the receptor well concentration of cadmium will not exceed 0.005 mg/l. See 55 FR 11826, March 29, 1990; 56 FR 32993, July 18, 1991; and 56 FR 67197, December30, 1991.\3\ DAF cutoff is 100, corresponding to the Toxicity Characteristic Rule(55 FR 11826, March 29, 1990).The Agency calculated delisting levels for UTA's chemically stabilized F006, based on the EPACML Model, as shown in Table 6.
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Table 6.--EPACML-Based Delisting Levels for Cadmium and Chromium in Landfill Waste (TCLP, mg/l)
Waste volume (cubic yards, Allowable one-time exclusion) Allowable TCLP \1\ ----------------------------- TCLP \1\ leachate leachate concentration