Risk-Based Waste Classification in California (1999) / Chapter Skim
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Appendix D: Letter of Introduction, Overview, Concept Paper, and Appendices 1-4 from DTSC Report
Appendix D: Letter of Introduction, Overview, Concept Paper, and Appendices 1-4 from DTSC Report
Pages 145-219
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From page 145... ...
Appendix D California Environmental Protection Agency Department of Toxic Substances Control [DISC] Letter of Introduction, Overview, Concept Paper, and Appendices I-4 frown DISC Report
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. TTLC Lower SERT Proposed Non-RCRA Waste Classification System t~CR~-H~,A _ ~ ..-~ .~ ~ .
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APPENDIX D: DTSC REPORT Risk-Based Criteria for Non RCRA Hazardous Waste Volume ~ of 2 A Report to the Nafiona/ Research Counci/ /nfroducing Proposed Changes to file Definition of Hazardous Waste in the California Code of Regu/afions Prepared by Human and Ecological Risk Division and Hazardous Materials Laboratory of the Science, Pollution Prevention, and Technology Program Department of Toxic Substances Control Environmental Protection Agency State of California February 27, 1998 147
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Vinyl chloride 11. 2,3,7,8-Tetrachlorodibenzo-p dioxin lilt Tnchloroethylene Volume 2 4b The DTSC Lead Risk Assessment Spreadsheet 4c The Preliminary Endangerment Assessment Model 4d De Nova Ecological Risk Assessments 5 Detection Limits and Background Level 5a Ambient and Background Concentrations 5b Analytical Issues 6 Concept Paper: Evaluation of the Suitability of the Federal Toxicity Characteristic Leaching Procedure (TCLP)
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The subject of this request for scientific review is the toxicity characteristic. Currently, a California waste is a non-RCRA hazardous waste due to the characteristic of toxicity if it exceeds any of eight criteria: It contains total concentrations of any of thirty-seven toxic constituents exceeding total threshold limit concentrations (mCs)
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In keeping with those premises, DTSC has proposed two tiers of l¢Cs and Soluble or Extractable Regulatory Thresholds (SERTs) to divide hazardous from special wastes and special wastes from non-hazardous wastes.
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Health benchmarks were California Environmental Protection Agency cancer potency factors and U.S. EPA reference doses for non-carcinogenic effects.
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An overview of the current California Waste Classification System and proposed changes.
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However, a generator can use testing or knowledge to show that a waste containing one or more of the chemicals on the presumptive list does not exhibit a hazardous characteristic. Thus, California's non-RCRA system does not have Listed hazardous wastes in the same way that the RCRA system does.
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Each of these criteria will be described in more detail under separate headings. Total Threshold Limit Concentrations (TTLCs)
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Thus, the scenarios for the upper TTLCs are associated with managed disposal in a municipal solid waste landfill meeting the specifications in RCRA subtitle D Similarly, the scenarios for the exit-level TTLCs are associated with use of the waste as a soil amendment.
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Upper TTLcs I ! Upper TTLCs | l Exit-level TTLCs I Exit-level TTLCs | Exit-level TTLCs | Exit-level TTLCs | Worker | Organics Worker | Inorganics Residen~Organics Resident Worker Resident Resident Resident I 1 Ecological I Inorganics | Lead Inorganics I 1 Organics _ad all I modified PEA | modified PEA CalTOX Landfill modified PEA I 1 Pb Spreadsheet | modified PEA | CalTOX Land Conversion I 1 1 Pb Spreadsheet I several Tabs3:Appendix 3 & 4c Tab 3:Appendix 3 & 4c Tab 3:Appendix 3 & 4a Tab 3:Appendix 3 & 4c Tab 3:Appendix 3 & 4b Tab 3:Appendix 3 & 4c Tab 3:Appendix 3 & 4a Tab 3:Appendix 3 & 4b !
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Liquid wastes are analyzed directly, without the extraction. The proposal would replace the WET with the RCRA Toxicity Characteristic Leaching Procedure (TCLP)
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(reference: Tab 3, Appendix 3 and fib) Scenano Selection · Are the waste management worker and the nearby resident scenarios appropriate to represent populations potentially exposed to lower-tier hazardous wastes?
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The U.S. EPA has withdrawn the oral cancer potency factor for beryllium.
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7~98 Is the Department's proposed approach to setting acute oral, dermal, and inhalation toxicity thresholds reasonable? (reference: Tab 3:Appendix 4)
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APPENDIX D: DTSC REPORT California Environmental Protection Agency Department of Toxic Substances Control Tab 3: Concept Paper CALIFORNIA'S NON-RCRA WASTE CLASSIFICATION SYSTEM: Analysis and Proposed Revisions February20, 1998 161 Authors: Jim Carlisle, D.V.M., M.Sc., Ned Butler, Ph.D., D.A.B.T., Kimi Klein, Ph.D., John Christopher, PhD, DABT, Bart Simmons, PhD.
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with its listed hazardous wastes and the toxicity characteristic. The preliminary conclusion of this task is that the RCRA system is incomplete and does not, by itself, adequately protect human health and the environment in Califomia (see draft concept paper for RSU task D-1)
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Existing Califomia regulations describing the characteristic of toxicity are found in 22CCR 66261.24. In addition to the RCRA toxicity characteristic, they include tables listing Soluble Threshold Limit Concentrations (STLCs)
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Con: This alternative would provide for no limits on total concentrations of hazardous constituents in wastes, thereby reducing protectiveness below that mandated by State statutes. The RCRA toxicity characteristic does not address exposure to toxic constituents via media other than ground water.
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Retaining a list of Total Threshold Limit Concentrations to identify a waste as hazardous is necessary to protect public health and the environment in Califomia. Such a list provides the public with clear guidance in classiflying a waste.
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With respect to the Soluble Threshold Limit Concentrations, the options considered were: Repeal the STLCs in 22CCR Subsection 66261.24 (a)
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Con: This alternative would not permit identification of wastes as hazardous based on their acute oral toxicity. This would reduce protectiveness below that mandated by state statutes because there may be waste constituents or combinations of waste constituents that may be acutely toxic for which chronic toxicity benchmarks have not been established.
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From page 168... ...
Con: This altemative would not permit identification of wastes as hazardous based on their acute dermal toxicity. This would reduce protectiveness below that mandated by state statutes because there may be waste constituents or combinations of waste constituents that may be acutely toxic for which chronic toxicity benchmarks have not been established.
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Con: This alternative would not permit identification of wastes as hazardous based on their acute inhalation toxicity. This would reduce protectiveness below that mandated by state statutes because there may be waste constituents or combinations of waste constituents that may be acutely toxic for which chronic toxicity benchmarks have not been established.
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From page 170... ...
Con: This alternative would not permit identification of wastes as hazardous based on their toxicity to fish. This would reduce protectiveness below that mandated by state statutes because there may be waste constituents or combinations of waste constituents that may be acutely toxic to fish for which chronic toxicity benchmarks have not been established.
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Pro: This alternative would be consistent win the proposed two-tier standards for the other toxicity criteria. Con: An upper tier of fish LC50 limits (creating an upper tier of hazardous wastes based on fish toxicity)
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There is no scientific reasons to consider carcinogens as a separate class of hazardous wastes. This altemative would allow generators of the formerly listed carcinogens to demonstrate that their wastes are not hazardous.
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Protection of the environment and public health requires that this toxicity characteristic be retained to protect against undue exposure to future wastes that are found to be hazardous to public health or the environment. Criterion 2.
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Special Wastes are a subset of hazardous wastes to which reduced regulatory requirements would apply. Table 1 presents proposed upper and lower SERTs along with current STLCs.
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Based on federal Ambient Water Qual~y Criteria ~ 100 ppm hardness or a pH of 6.5 and the longest available exposure, and a dilution/attenuation factor of 100 (the initial value of 0.0002 for toxaphene was raised to the PQL)
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The current TTLC for PCBs is being retaind pending anticipated changes in analytical methods and toxicological benchmarks. No upper TTLCs are proposed for zinc and total chromium because the calculated values for these standards are at or near 1 million ppm.
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| 100.000 | HBL | nonef l l 10.000 BerviliUm | 20 | HBL | nonef | | 75 Cadmium | 150 | HBL | 60 | HBL | 100 Hexavalent Chromium | 5 | HBL | nonef | | 500 Total Chromium | none h | HBL | none h | HBL | 2500 ~1 1 ~ Cobalt 1 15 000 | HBL I nonef I 1 8000 Conoer | 70 000 | HBL | nonef l l 2.500 Fluoride | 100 000 | HBL | nonef l l 18.000 Lead 1 6000 1 HBL I 1000 1 HBL I 1.000 MercurvC | 500 | HBL | 7 | ambient | 20 Molvbdenum I 9000 I HBL I nonef I 1 3.500 Nickel | 3000 | HBL | nonef l l 2,000 Selenium 30 I STLC | none 1 1 100 Silver I none (see text) I none (see text)
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DTSC recommends the adoption of two-tiered acute toxicity criteria to ensure that highly toxic substances are managed so as to avoid exposures at toxic levels while not over-regulating chemicals of moderate acute toxicity. DTSC has developed recommended acute toxicity thresholds for hazardous wastes and special wastes.
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Non-hazardous wastes would include those with an oral LDso exceeding 500 mg/kg. Special wastes would include wastes with oral LDsos between 30 and 500 mglkg.
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Wastes wan aquatic LC50s below 500 mg/1, but above 30 mgil would be classified as special wastes. With concurrence from the Regional Water Quality Control Board, special wastes could be disposed of in lined municipal solid waste landfills meeting current RCRA Subtitle D requirements for new landfills.
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Chlordane is highly toxic to aquatic organisms. The CaUEPA oral and inhalation cancer potency factor is 1.2 (mg/kg-day)
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It bioaccumulates in fish and other aquatic organisms. The proposed TALC is based on the CallEPA oral and inhalation cancer potency factor of 0.018 (mgilcg~ay)
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It is minimally toxic to aquatic organisms. The Cal/EPA considers TCE a potential human carcinogen with an oral cancer potency factor of 0.015 (mg/kg~ay)
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Vinyl chloride is one of the few chemicals to have been shown to cause cancer in humans. The CAVEPA oral and inhalation cancer potency factor is 0.27 (mg/kg~ay)
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The U.S. EPA Ambient Water Quality Criterion is 12 ugA.
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The U.S. EPA Ambient Water Quality Criterion is 110 ug/1.
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These values consider only exposure to humans from drinking ground water. To calculate health-based levels for carcinogenic constituents, cancer potency factors developed by the Office of Environmental Health Hazard Assessment within the California Environmental Protection Agency (if available, otherwise U.S.
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.S.EPA in developing the RCRA Toxicity Characteristic regulatory limits, and is intended to account for the dilution and attenuation that occur as leachates move through the unsaturated zone and mix with ground water.
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DTSC's mandate to protect public health and the environment does not include regulation to below background concentrations, and therefore we propose to use 0.01 mg/l as the target arsenic concentration limit in ground water. With an assumed dilution/attenuation factor of 100, the limit in liquid waste would be 1 mg/1.
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APPENDIX D: DTSCREPORT 191 Basis for Lower SERTs and comparison win current regulatory thresholds (mg/l)
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EPA cancer potency factor with CalTOX exposure parameters.
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APPENDIX D: DTSCREPORT 193 Basis for Upper SERTs and Comparison with Current Regulatory Thresholds (mg/l)
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The following table shows the proposed upper and lower TTLCs, the STLCs and computed maximum concentrations (in mg/l) in the leachates.
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Wastes with concentrations above the upper TTLC value would be in group 1, wastes with concentrations lower than the lower TALC would be in group 3 and wastes with any constituent concentration levels between the upper and lower TTLCs would be in group 2, provided that they were not classified in group 1 by any other characteristic. Human and Ecological Risk Division 38 U ~ ~ G S ~2J27198
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.1 l | Proposed Exit TTLC | Comparisons conducted for dioxin and inorganic chemicals Figure 1: Decision Tree for Determining Exit TTLCs for Each Chemical Figure 1 shows that for each chemical a decision was made to select a concentration that would protect both residents and non-human species living on or near land to which waste containing the TTLC chemical had been added. The scenario for residents is called the Land Conversion Scenario because the land is converted from uninhabited land to inhabited residential lots after waste ceases to be plowed into the soil.
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The reasons for these decisions are as follows: Twice the Estimated Quantitation Limit was selected over a risk-based value because regulated industries must be able to measure the TTLC concentration, otherwise, it is not possible to determine if one is complying with the law. Worldwide ambient concentrations of dioxins and dibenzofurans exceed calculated health-based concentrations.
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Such a relationship between dose and risk of cancer is called a cancer potency factor. If an OEHHA potency factor exists for a specific chemical, this value is used in relating risk to dose.
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Environmental media are the air, ground water, surface water and soil which are located above, below or adjacent to the waste. Nearby residents do not breath air which is directly above the landfill or have direct contact with landfill constituents.
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Therefore, risks associated with solid waste landfill disposal are an appropriate basis for establishing risk-based upper TTLC levels. The lower TTLC is used to distinguish waste that need not be regulated by DTSC from waste regulated by DTSC.
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All people are protected at least to the level of waste workers because of a policy decision resulting from the comparison of proposed exit and upper TTLCs. If the proposed exit TTEC exceeds the proposed upper TALC, than no exit TTLC is proposed and no special waste category can be established for a given chemical.
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Landfill Organic Conversion Process Inorganic Lead LeadSpread LeadSpread LeadSpread Multi-tiered Off-site Worker Land Process Conversion Inorganic PEA Off-site PEA Worker PEA Land Multi-tiered Chemicals Inorganic Conversion Process Modified versions of the CalTOX model were used for the residential scenarios for organic chemicals for both the upper and lower TTLC. Modified versions of the LeadSpread model were used for all human Human and Ecological Risk Division 45 OU0057 2127J9e
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model were used for all human exposures to inorganic chemicals other than lead and waste worker exposure to organic chemicals. The ecological effects for all chemicals were evaluated by using a screening process to identify chemicals for which ecological effects occurred at lower doses than for human health effects.
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CalTOX Land Conversion was created by computing the root soil concentration from an application rate, mixing depth, application duration and waste concentration rather than specifying an initial root soil concentration. The values for these new parameters were the point estimates cited in the US EPA technical background document used in promulgating the regulations for biosolid application to land Human and Ecologicai Risk Division 47 000059 2t27198
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These data have been used to develop a model for predicting a relationship of the soil concentration of lead and potential health effects. This model is implemented as a Department of Toxic Substances Control Lead Risk Assessment Spreadsheet (LeadSpread)
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Since none of the applications of PEA in calculating TTLCs is identical to a hazardous waste site, some modifications had to be made. The PEA method was translated into spreadsheet form to estimate Talcs for three scenarios: exposures to organic and inorganic chemicals for onsite hazardous waste workers, exposure to inorganic chemicals for a resident near a landfill, and exposure to inorganic chemicals for a resident on converted land (Table 1)
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From page 207... ...
The other eight were considered low priority in the HWIR analysis and therefore are not likely to present significant threats to ecosystems at concentrations below those that would be of concern for human health. For 18 of the 29 chemicals the human toxicity exit concentration was lower than the ecological toxicity exit concentration, indicating that for those 18 chemicals, human-health-based lower TTLCs would be likely to also protect other species.
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10 none ToxaDhene 0.00003 0.001 Silvex 100 400 Vinvl chlonde 0.06 none Antimonv 2 4 Arsenic 0.08 10 Banum 2000 4000 Bervilium 0.01 20 Cadmium 10 Hexavalent Chromium 10 2~ CobaR none none CODDer 900 1 Fluoride none none ead 200 1 Mercurv 5 0.2 Molvbdenum 100 200 Nickel 1000 20 Selenium 8 0.4 Thallium . 2 none Vanadium 300 20 Zinc 8000 0.4 Lower value shown in bold ~ Sah~e value as proposed 1lLC based on human healtt, Human and Ecological Risk Division 51 O0006s' 2~2?
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However, in order to be consistent with the approach used throughout this proposed revision of the waste classification system, the approach of Van Derveer and Canton (Tab 8) was selected as the basis for the proposed lower TTLC for selenium.
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The HWIR benchmark dose for Bedim ent-dwelling organisms is converted from the ambient water quality criterion for the protection of aquatic life (AWQC) of 0.00003 mg/1, using equilibrium partitioning.
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From page 211... ...
_ ToxaDhene 2.4.5-TrichloroDhenoxvDroDrionic acid Vlnvl chloride 2.3.7.~Tetrachlorodibenzodioxin Inoreanic lead Antimonv Arsenic Asbestosb Barium (excludina barite) Bervilium Cadmium Trivalent ChromiumC Hexavalent Chromium Cobalt CoDDer Fluoride ionic Mercurv Molvbdenum Nidrel Selenium Thallium Vanadium 500 nd 20 0.04 2.000 0.2 7X10-7 20.000 15.000 200 nd >1,000.000 300 150 >~.000.000 15,000 >1.000.000 >1 .000.000 10.000 200.000 3.000 200.000 3.000 300.000 Zinc >1.000.000 Human and Ecological Risk Division _ 0.0009 006 .
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From page 212... ...
Since the objective of the TTECs is to model the exposure pathways other than those involving ground water, the chemical characteristics of the unionized form were used to predict the fate of these chemicals in the environment. At pH values between 5 and 9, the environmental fate of pentachlorophenol will be well represented by the CalTOX equations; prediction errors are larger for 2,~D and 2,4,5-T.
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From page 213... ...
Risk-based candidate TTEC which were less than twice the EQL were changed to twice the EQL. The proposed upper TTLC for toxaphene and proposed lower TTLCs for chlordane, heptachlor, methoxychlor, toxaphene, Silvex, and vinyl chloride are based on EQLs.
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. The concentration in waste that would produce such change in soil, estimated using the land conversion scenario, was 0.0002 mg/kg (0.00001 x 19.8)
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From page 215... ...
Toxanhene 2.4.~T Vinyl chlonde PCDD/PCDF {TEQs~b Inorganic lead Antimony Arsenic Asbestos' 0.006 1 3000 0.2 70 0.7 0.2 8x10 30 2000 0.9 500 nd 20 0.04 2000 0.2 7x107 6000 700 50 nd Barium (excludinq barite) 100.000 Bervilium Cadmium Hexavalent Chromium Cobalt Copper Fluoride ionic Mercury Molybdenum Nicicel Selenium Thallium Vanadium Zinc 0.01 See commentb Q.6 30 2Q0 5 10.000 60.000 100.000 5Q0 9.000 3~000 .
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d The lower TALC values were greater than the upper TTLC, e The maximum waste concentration based on background considerations. f These are the upper TALC values.
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Uncertainty factors of ten to account for the use of laboratory animal toxicity data to predict human toxicity and ten to extrapolate from a lethal concentration to a minimal-effect concentration were multiplied by the waste ingestion rates to arrive at the acute oral toxicity thresholds. Dermal LD~o DTSC has developed recommended acute dermal toxicity thresholds for hazardous wastes and special wastes.
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From page 218... ...
Volatiles: In order to account for both a chemical's acute inhalation toxicity and its tendency to vapor ze, classification of a waste containing volatile constituents would be based on the ratio of each constituent chemical's vapor pressure (in ppm ~ 250 C) to its inhalation LC50 (in ppm)
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From page 219... ...
DISC proposes to classify a waste with an LCso c500 mg/1 as a special waste. A concentration of 500 mg/1 would be equivalent to 7 tons in a two-acre lake five feet deep with complete mixing, which DISC considers to be a reasonable worst-case release.
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