oEFA United States Environmental Protection Agency Off ice ot Water Regulations and Standards Washington, DC 20460 Water June, 1985 Environmental Profiles and Hazard Indices for Constituents of Municipal Sludge: Hexachlorobutadiene ------- PREFACE This document is one of a series of preliminary assessments dealing with chemicals of potential concern in municipal sewage sludge. The 'purpose of these documents is to: (a) summarize the available data for the constituents of potential concern, (b) identify the key environ- mental pathways for each constituent related to a reuse and disposal option (based on hazard indices), and (c) evaluate the conditions under which such a pollutant may pose a hazard. Each document provides a sci- entific basis for making an initial determination of whether a pollu- tant, at levels currently observed in sludges, poses a likely hazard to human health or the. environment when sludge is disposed of by any of several methods. These methods include landspreading on food chain or nonfood chain crops, distribution and marketing programs, landfilling, incineration and ocean disposal. These documents are intended to serve as a rapid screening tool to narrow an initial list of pollutants to those of concern. If a signifi- cant hazard is indicated by this preliminary analysis, a more detailed assessment will be undertaken to better quantify the risk from this chemical and to derive criteria if warranted. If a hazard is shown to be unlikely, no further assessment will be conducted at this time; how- ever, a reassessment will be conducted after initial regulations are finalized. In no case, however, will criteria be derived solely on the basis of information presented in this document. ------- TABLE OP CONTENTS Page PREFACE i 1.- INTRODUCTION 1-1 2. PRELIMINARY CONCLUSIONS FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE.. • 2-1 Landspreading and Distribution-and-Marketing 2-1 Landfilling 2-2 Incineration 2-2 Ocean Disposal 2-2 3. PRELIMINARY HAZARD INDICES FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE 3-1 Landspreading and Distribution-and-Marketing 3-1 Effect on soil concentration of hexachlorobutadiene (Index 1) 3-1 Effect on soil biota and predators of soil biota (Indices 2-3) , 3-3 Effect on plants and plant tissue concentration (Indices 4-6) 3-4 Effect on herbivorous animals (Indices 7-8) 3-6 Effect on humans (Indices 9-13) 3-9 Landf illing 3-16 Incineration 3-16 Ocean Disposal 3-16 4. PRELIMINARY DATA PROFILE FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE 4-1 Occurrence 4-1 Sludge 4-1 Soil - Unpolluted 4-2 Water - Unpolluted 4-2 Air 4-3 Food 4-3 11 ------- TABLE OF CONTENTS (Continued) Page Human Effects 4-3 Ingestion 4-3 Inhalation 4-4 Plant Effects 4-4 Domestic Animal and Wildlife Effects 4-4 Toxicity 4-4 Uptake .... 4-4 Aquatic Life Effects 4-4 Soil Biota Effects 4-4 Physicochemical Data for Estimating Fate and Transport 4-4 5. REFERENCES .- 5-1 APPENDIX. PRELIMINARY HAZARD INDEX CALCULATIONS FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE'SLUDGE A-l ill ------- SECTION 1 INTRODUCTION This preliminary data profile is one of a series of profiles dealing with chemical pollutants potentially of concern in municipal sewage sludges. Hexachlorobutadiene (HCBD) was initially identified as being of potential concern when sludge is landspread (including distribution and marketing).* This profile is a compilation of information that may be useful in determining whether UCBD poses an actual hazard to human health or the environment when sludge is disposed of by this method. The focus of this document is the calculation of "preliminary hazard indices" for selected potential exposure pathways, as shown in Section 3. Each index illustrates the hazard that could result from movement of a pollutant by a given pathway to cause a given effect (e.g., sludge •* soil •* plant uptake •* animal uptake •* human toxicity). The values and assumptions employed in these calculations tend to represent a reasonable "worst case"; analysis of error or uncertainty has been conducted to a limited degree. The resulting value in most cases is indexed to unity; i.e., values >1 may indicate a potential hazard, depending upon the assumptions of the calculation. The data used for index calculation have been selected or estimated based on information presented in the "preliminary data profile", Section 4. Information in the profile is based on a compilation of the recent literature. An attempt has been made to fill out the profile outline to the greatest extent possible. However, since this is a pre- liminary analysis, the literature has not been exhaustively perused. The "preliminary conclusions" drawn, from each index in Section 3 are summarized in Section 2. The preliminary hazard indices will be used as a screening tool to determine which pollutants and pathways may pose a hazard. Where a potential hazard is indicated by interpretation of these indices, further analysis will include a more detailed exami- nation of potential risks as well as an examination of site-specific factors. These more rigorous evaluations may change the preliminary conclusions presented in Section 2, which are based on a reasonable "worst case" analysis. The preliminary hazard indices for selected exposure routes pertinent to landspreading and distribution and marketing practices are included in this profile. The calculation formulae for these indices are shown in the Appendix. The indices are rounded to two significant figures. * Listings were determined by a series of expert workshops convened during March-May, 1984 by the Office of Water Regulations and Standards (OWES) to discuss landspreading, landfilling, incineration, and ocean disposal, respectively, of municipal sewage sludge. 1-1 ------- SECTION 2 . PRELIMINARY CONCLUSIONS FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE The following preliminary conclusions have been derived from the calculation of "preliminary hazard indices", which represent conserva- tive or "worst case" analyses of hazard. The indices and their basis and interpretation are explained in Section 3. Their calculation formulae are shown in the Appendix. I. LANDSPREADING AND DISTRIBUTION-AMD-MARKETING A. Effect on Soil Concentration of Hexachlorobutadiene Landspreading of sludge is not expected to increase soil concentrations of HCBD, except possibly a slight increase when sludge containing a worst-case concentration of HCBD is applied at the highest rate (see Index 1). B. Effect on Soil Biota or Predators of Soil Biota Conclusions were not drawn because index values could not be calculated due to lack of data. C. Effect on Plants and Plant Tissue Concentration Conclusions were not drawn because index values could not be calculated due to lack of data. D. Effect on Herbivorous Animals Due to lack of data, conclusions were not drawn regarding the effect on herbivorous animals from consumption of plants grown on sludge-amended soil (see Index 7). Landspreading of sludge is not expected to pose a toxic hazard to grazing animals through inadvertent ingestion of sludge containing HCBD (see Index 8). E. Effect on Humans Due to lack of data, conclusions were not drawn regarding the cancer risk resulting from human consumption of plants grown on sludge-amended soil or human consumption of animal products derived from animals feeding on plants grown on sludge-amended soils (see Indices 9 and 10). The human consumption of animal products derived from animals that have inadvertently ingested sludge-amended soils may pose a risk of cancer to humans, except for adults when sludge containing typical concentrations of HCBD is applied (see Index 11). Inadvertent ingestion of sludge-amended soil is 2-1 ------- not expected to pose a cancer risk to humans except possibly for toddlers ingesting soil amended with sludge containing high concentrations of HCBD at high application rates (50 and 500 mt/ha) (see Index 12). Due to lack of data, conclusions were not drawn regarding the aggregate human cancer risk (see Index 13). II. LANDPILLING Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), ah assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. III. INCINERATION Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. IV. OCEAN DISPOSAL Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. 2-2 ------- SECTION 3 PRELIMINARY HAZARD INDICES FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE I. LANDSPREADING AND DISTRIBUTION-AMD-MARKETING A. Effect on Soil Concentration of Hexachlorobutadiene 1. Index of Soil Concentration (Index 1) a. Explanation - Calculates concentrations in Ug/g DW of pollutant in sludge-amended soil. Calculated for sludges with typical (median, if available) and worst (95 percentile, if available) pollutant concentrations, respectively, for each of four applications. Loadings (as dry matter) are chosen and explained as follows: 0 mt/ha No sludge applied. Shown for all indices for purposes of comparison, to distin- guish hazard posed by sludge from pre- existing hazard posed by background levels or other sources of the pollutant. 5 mt/ha Sustainable yearly agronomic application;' i.e., loading typical of agricultural practice, supplying . ^50 kg available nitrogen per hectare. 50 mt/ha Higher single application as may be used on public lands, reclaimed areas or home gardens. 500 mt/ha Cumulative loading after 100 years of .application at 5 mt/ha/year. b. Assumptions/Limitations - Assumes pollutant is incorporated into the upper 15 cm of soil (i.e., the plow layer), which has an approximate mass (dry matter) of 2 x 10^ mt/ha and is then dissipated through first order processes which can be expressed as a soil half-life. c. Data Used and Rationale ii Sludge concentration of pollutant (SC) Typical 0.3 Ug/g DW Worst 8.0 ug/g DW The typical and worst sludge concentrations are the weighted mean and maximum values, 3-1 ------- respectively, statistically derived for combined sludge concentration data from several surveys of publicly-owned treatment works (POTWs) (Camp Dresser and McKee, Inc. (COM), 1984). These values are based on detected samples and thus constitute conservative values. (See Section, p. 4-1.) ii. Background concentration of pollutant in soil (BS) = 0 ug/g DW Background soil concentration of UCBD is assumed to be zero (0). Data immediately available on the background concentrations of HCBD in soil are limited. Studies conducted at several chlorinated hydrocarbon plants on soils expected to contain HCBD found levels ranging from 0 (none detected) to 980 Ug/g- The high values are all from sites immediately adjacent to production plants and are thus not considered representative of U.S. soils (U.S. EPA, 1976). It is assumed that agricultural and garden soils would be at the low end of this range. (See Section 4, p. 4-2.) iii. Soil half-life of pollutant (tp = 0 years Immediately available data does not provide a t^. value. A value of 0 is assumed in- order for the cumulative loading values to be calculated. d. Index 1 Values (yg/g DW) Sludge Application Rate (mt/ha) Sludge Concentration 0 5 50 500 Typical Worst 0.0 0.0 0.00075 0.020 0.0073 0.20 0.06 1.6 Value Interpretation - Value equals the expected concentration in sludge-amended soil. Preliminary Conclusion - Landspreading of sludge is not expected to increase soil concentrations of UCBD, except possibly a slight increase when sludge containing a worst-case concentration of HCBD is applied at the highest rate. 3-2 ------- B. Effect on Soil Biota and Predators of Soil Biota 1. Index of Soil Biota Toxicity (Index 2) a. Explanation - Compares pollutant concentrations in sludge-amended soil with soil concentration shown to be toxic for some soil organism. b. Assumptions/Limitations - Assumes pollutant form in sludge-amended soil is equally bioavailable and toxic as form used in study where toxic effects were demonstrated. c. Data Used and Rationale 'i. Concentration of pollutant in sludge-amended soil (Index 1) See Section 3, p. 3-2. ii. Soil concentration toxic to soil biota (TB) - Data not immediately available. d. Index 2 Values - Values were not calculated due to lack of data. e. Value Interpretation - Value equals factor by which expected soil concentration exceeds toxic concentra- tion. Value > 1 indicates a toxic hazard may exist .for soil biota. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 2. Index of Soil Biota Predator Toxicity (Index 3) a. Explanation - Compares pollutant concentrations expected in tissues of organisms inhabiting sludge- amended soil with food concentration shown to be toxic to a predator on soil organisms. b. Assumptions/Limitations - Assumes pollutant form bioconcentrated by soil biota is equivalent in toxicity to form used to demonstrate toxic effects in predator. Effect level in predator may be estimated from that in a different species. c. Data Used and Rationale i. Concentration of pollutant in sludge-amended soil (Index 1) See Section 3, p. 3-2. 3-3 ------- ii. Uptake factor of pollutant in soil biota (UB) - Data not immediately available. iii. Peed concentration toxic to predator (TR) - Data not immediately available. d. Index 3 Values - Values were not calculated due to lack of data. e. Value Interpretation - Values equals factor by which expected concentration in soil biota exceeds that which is.toxic to predator. Value > 1 indicates a toxic hazard may exist for predators of soil biota. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. C. Effect on Plants and Plant Tissue Concentration 1. Index of Phytotoxic Soil Concentration (Index 4) a. Explanation - Compares pollutant concentrations in sludge-amended soil with the lowest soil concentration shown to be toxic for some plants. b. Assumptions/Limitations - Assumes pollutant form in sludge-amended soil is equally bioavailable and toxic as form used in 'study where toxic effects were demonstrated. c. Data Used and Rationale i. Concentration of pollutant in sludge-amended soil (Index 1) See Section 3, p. 3-2. ii. Soil concentration toxic to plants (TP) - Data not immediately available. d. Index 4 Values - Values were not calculated due to lack of data. e. Value Interpretation - Value equals factor by which soil concentration exceeds phytotoxic concentration. Value > 1 indicates a phytotoxic hazard may exist. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 3-4 ------- 2. Index of Plant Concentration Caused by Uptake (Index 5) a. Explanation - Calculates expected tissue concentrations, in Ug/g DW, in 'plants grown in sludge-amended soil, using uptake data for the most responsive plant species in the following categories: (1) plants included in the U.S. human diet; and (2) plants serving as animal feed. Plants used vary 'according to availability of data. b. Assumptions/Limitations - Assumes an uptake factor that is constant over all soil concentrations. The uptake factor chosen for the human diet is assumed to be representative of all crops (except fruits) in the human diet. The uptake factor chosen for the animal diet is assumed to be representative of all crops in the animal diet. See also Index 6 for consideration of phytotoxicity. c. Data Used and Rationale i. Concentration of pollutant in sludge-amended soil (Index 1) See Section 3, p. 3-2. ii. Uptake factor of pollutant in plant tissue (UP) r Data not immediately available. d. Index 5 Values - Values were not calculated due to lack of data. e. Value Interpretation - Value equals the expected concentration in tissues of plants grown in sludge- amended soil. However, any value exceeding the value of Index 6 for the same or a similar plant species may be unrealistically high because it would be precluded by phytoxicity. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 3. Index of Plant Concentration Permitted by Phytotoxicity (Index 6) a. Explanation - The index value is the maximum tissue concentration, in Pg/g DW, associated with phytotoxicity in the same or similar plant species used in Index 5. The purpose is to determine whether the plant tissue concentrations determined 3-5 ------- in Index 5 for high applications are realistic, or whether such concentrations would be precluded by phytotoxicity. The maximum concentration should be the highest at which some plant growth still occurs (and thus consumption of tissue by animals is possible) but above which consumption by animals is unlikely. b. Assumptions/Limitations - Assumes that tissue concentration will be a consistent indicator of phytotoxicity. c. Data Used and Rationale i. Maximum plant tissue concentration associated with phytoxicity (PP) - Data not immediately available. t d. Index* 6 Values (yg/g DW) - Values were not calculated due to lack of data. e. Value Interpretation - Value equals the maximum plant tissue concentration which is permitted by phytotoxicity. Value is compared with values for the same or similar plant species given by Index 5. The lowest of the two indices indicates the maximal increase that can occur at any given application ra*te. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. D. Effect on Herbivorous Animals 1. Index of Animal Toxicity Resulting from Plant Consumption (Index 7) a. Explanation - Compares pollutant concentrations expected in plant tissues grown in sludge-amended soil with feed concentration shown to be toxic to wild or domestic herbivorous animals. Does not con- sider direct contamination of forage by adhering sludge. b. Assumptions/Limitations - Assumes pollutant form taken up by plants is equivalent in toxicity to form used to demonstrate toxic effects in animal. Uptake or toxicity in specific plants or animals may be estimated from other species. 3-6 ------- c. Data Used and Rationale i. Concentration of pollutant in plant grown in sludge-amended soil (Index 5) -. Values were not calculated due to lack of data. ii. Peed concentration toxic to herbivorous animal (TA) = 30 Ug/g DW Since there is no data for grazing animals, the toxicity value for rats is used to approximate toxic concentrations for herbivorous animals. A dosage of 30 Ug/g produced slight renal toxicity (Kociba et al., 1977). (See Section 4, p. 4-6.) d. Index 7 Values - Values were not calculated due to lack of data. e. Value Interpretation - Value equals factor by which expected plant tissue concentration exceeds that which is toxic Co animals. Value > 1 indicates a toxic hazard may exist for herbivorous animals. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 2. Index of Animal Toxicity Resulting from Sludge Ingestion (Index 8) a. Explanation - Calculates the amount of pollutant in a grazing animal's diet resulting from sludge adhesion to forage or from incidental ingestion of sludge-amended soil and compares this with the dietary toxic threshold concentration for a grazing animal. b. Assumptions/Limitations - Assumes that sludge is applied over and adheres to. growing forage, or that sludge constitutes 5 percent of dry matter in the grazing animal's diet, and that pollutant form in sludge is equally bioavailable and toxic .as form used to demonstrate toxic effects. Where no sludge is applied (i.e., 0 mt/ha), assumes diet is 5 per- cent soil as a basis for comparison. 3-7 ------- Data Used and Rationale i. Sludge concentration of pollutant (SC) Typical 0.3 Ug/g DW Worst 8.0, ug/g DW See Section 3, p. 3-1. ii. Fraction of animal diet assumed to be soil (GS) = 5% Studies of sludge adhesion to growing forage following applications of liquid or filter-cake sludge show that when 3 to 6 mt/ha of sludge solids is applied, clipped forage initially consists of up to 30 percent sludge on a dry- weight basis (Chaney and Lloyd, 1979; Boswell, 1975). However, this contamination diminishes gradually with time and growth, and generally is not detected in the following year's growth. For example, where pastures amended at 16 and 32 mt/ha were grazed throughout a growing sea- son (168 days), average sludge content of for- age was only 2.14 and 4.75 percent, respectively (Bertrand et al., 1981). It seems reasonable to assume that animals may receive long-term dietary exposure to 5 percent sludge if maintained on a forage to which sludge is regularly applied. This estimate of 5 percent sludge is used regardless of application rate, since the above studies did not show a clear relationship between application rate and ini- tial contamination, and since adhesion is not cumulative yearly because of die-back. Studies of grazing animals indicate that soil ingestion, ordinarily <10 percent of dry weight of diet, may reach as high as 20 percent for cattle and 30 percent for sheep during winter months when forage is reduced (Thornton and Abrams, 1983). If the soil were sludge- amended, it is conceivable that up to 5 percent sludge may be ingested in this manner as well. Therefore, this value accounts for either of these scenarios, whether forage is harvested or grazed in the field. iii. Peed concentration toxic to herbivorous animal (TA) - 30 Ug/g DW See Section 3, p. 3-7. 3-8 ------- Index 8 Values Sludge Application Rate (mt/ha) Sludge Concentration 0 5 50 500 Typical 0 0.0005 0.0005 0.0005 Worst 0 0.013 0.013 0.013 e. Value Interpretation - Value equals factor by which expected dietary concentration exceeds toxic concen- tration. Value > 1 indicates a toxic hazard may exist for grazing animals. f. Preliminary Conclusion - Landspreading of sludge is not expected to pose a toxic hazard to, grazing animals through inadvertent ingestion of sludge containing HCBD. B. Effect on Humans 1. Index of Human Cancer Risk Resulting from Plant Consumption (Index 9) a. Explanation - Calculates dietary intake expected to result from consumption of crops grown on sludge- amended soil. Compares dietary intake with the cancer risk-specific intake (RSI) of the pollutant. b. Assumptions/Limitations - Assumes that all crops are grown on sludge-amended soil and that all those con- sidered to be affected take up the pollutant at the same rate. Divides possible variations in dietary intake into two categories: toddlers (18 months to 3 years) and individuals over 3 years old. c. Data Used and Rationale i. Concentration of pollutant in plant grown in sludge-amended soil (Index 5) - Values were not calculated due to lack of data. ii. Daily human dietary intake of affected plant tissue (DT) Toddler 74.5 g/day Adult 205 g/day The intake value for adults is based on daily intake of crop foods (excluding fruit) by 3-9 ------- vegetarians (Ryan et al., 1982); vegetarians were chosen to represent the worst case. The value for toddlers is based on the FDA Revised Total Diet (Pennington, 1983) and food groupings listed by the U.S. EPA (1984). Dry weights for individual food groups were estimated from composition data given by the U.S. Department of Agriculture (USDA) (1975). These values were composited to estimate dry- weight consumption of all non-fruit crops. iii. Average daily human dietary intake of pollutant (DI) Toddler 0 Ug/day Adult 0 Ug/day The average daily human dietary intake of HCBD is assumed to be zero (0). A survey of milk, eggs, and vegetable samples in areas where HCBD contamination would be expected to be greatest detected no HCBD in the samples (U.S. EPA, 1980). (See Section 4, p. 4-3.) iv. Cancer potency = 0.0775 (mg/kg/day) ""* The cancer potency value was derived from data • presented in U.S. EPA, 1980 for a study in which rats dosed orally with HCBD developed renal tubular adenomas and carcinoma (U.S. EPA, 1980). (See Section 4, p. 4-4.) v. Cancer risk-specific intake (RSI) = 0.90 tig/day The RSI is the pollutant intake value which results in an increase in cancer risk of 10~° (1 per 1,000,000). The RSI is calculated from the cancer potency using the following formula: RSI _ 1Q"6 x 70 kg x 1Q3 ug/mg Cancer potency d. Index 9 Values - Values were not calculated due to lack of data. e. Value Interpretation - Value > 1 indicates a potential increase in cancer risk of > 10"^ (1 per 1,000,000). Comparison with the null index value at 0 mt/ha indicates the degree to which any hazard is due to sludge application, as opposed to pre- existing dietary sources. 3-10 ------- f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 2. Index of Human Cancer Risk Resulting from Consumption of Animal Products Derived from Animals Feeding on Plants (Index 10) a. Explanation - Calculates human dietary intake expected to result from pollutant uptake by domestic animals given feed grown on sludge-amended soil (crop or pasture land) but not directly contaminated by adhering sludge. Compares expected intake with RSI. b. Assumptions/Limitations - Assumes that all animal products are from animals receiving all their feed from sludge-amended soil,. Assumes that all animal products . consumed take up the pollutant at the highest rate observed for muscle of any commonly consumed species or at the rate observed for beef liver or dairy products (whichever is higher). Divides possible variations in dietary intake into two categories: toddlers (18 months to 3 years) and individuals over 3 years old. c. Data Used and Rationale « i. Concentration of pollutant in plant grown in sludge-amended soil (Index 5) - Values were not calculated due to lack of data. ii. Uptake factor of pollutant in animal tissue (UA) = 3.5 Ug/g tissue DW (yg/g feed DW)"1 Available data on animal uptake of HCBD are very limited. The UA value used is for rats (kidney fat). The high end of the 1.75 to 3.5 bioconcentration (uptake) factor range was selected to provide a conservative analysis (U.S. EPA, 1980). The uptake factor of pollutant in animal tissue (UA) used is assumed to apply to all animal fats. (See Section 4, p. 4-6.) iii. Daily human dietary intake of affected animal tissue (DA) Toddler 43.7 g/day Adult 88.5 g/day 3-11 ------- The fat intake values presented, which comprise meat, fish, poultry, eggs and milk products, are derived from the FDA Revised Total Diet (Pennington, 1983), food groupings listed by the U.S. EPA (1984) and food composition data given by USDA (1975). Adult intake of meats is based on males 25 to 30 years of age and that for milk products on males 14 to 16 years of age, the age-sex groups with the highest daily intake. Toddler intake of milk products is actually based on infants, since infant milk consumption is the highest among that age group (Pennington, 1983). iv. Average daily human dietary intake of pollutant (DI) Toddler 0 ug/day Adult 0 Ug/day See Section 3, p. 3-10. v. Cancer risk-specific intake (RSI) = 0.90 pg/day See Section 3, p. 3-10. d. Index 10 Values - Values were not calculated due to lack of data. e. Value Interpretation - Same as for Index 9. f. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. 3. Index of Human Cancer Risk Resulting from Consumption of Animal Products Derived from Animals Ingesting Soil (Index 11) a. Explanation - Calculates human dietary intake expected to result from consumption of animal products derived from grazing animals incidentally ingesting sludge-amended soil. Compares expected intake with RSI. b. Assumptions/Limitations - Assumes that all animal products are from animals grazing sludge-amended soil, and that all animal products consumed take up the pollutant at the highest rate observed for muscle of any commonly consumed species or at the rate observed for beef liver or dairy products 3-12 ------- (whichever is higher). Divides possible variations in dietary intake into two categories: toddlers (18 months to 3 years) and individuals over 3 years old. Data Used and Rationale i. Animal tissue - kidney fat ii. Sludge concentration of pollutant (SC) Typical 0.3 Ug/g DW Worst 8.0 Ug/g DW See Section 3, p. 3-1. iii. Background concentration of pollutant in soil , (BS) = 0 Ug/g DW See Section 3, p. 3-2. iv. Fraction of animal diet assumed to be soil (GS) = 52 See Section 3, p. 3-8. v. Uptake factor of pollutant in animal tissue (UA) = 3.5 Ug/g tissue DW (ug/g feed DW)-1 See Section 3, p. 3-11. vi. Daily human dietary intake of affected' animal tissue (DA) Toddler 39.4 g/day Adult 82.4 g/day The affected tissue intake value is assumed to be from the fat component of meat only (beef, pork, lamb, veal) and milk products (Pennington, 1983). This is a slightly more limited choice than for Index 10. Adult intake of meats is based on males 25 to 30 years of age and the intake for milk products on males 14 to 16 years of age, the age-sex groups with the highest daily intake. Toddler intake of milk products is actually based on infants, since infant milk consumption is the highest among that age group (Pennington, 1983). 3-13 ------- vii. Average daily human dietary intake of pollutant (DI) Toddler 0 yg/day Adult 0 yg/day See Section 3, p. 3-10. viii. Cancer risk-specific intake (RSI) = 0.90 yg/day See Section 3, p. 3-10. d. Index 11 Values Sludge Application Rate (mt/ha) Sludge Group Concentration 0 5 50 500 Toddler Typical Worst 0.0 0.0 2.3 61 2.3 61 2.3 61 Adult Typical 0.0 0.48 0.48 0.48 Worst 0.0 13 13 13 e. Value Interpretation - Same as for Index 9. f. Preliminary Conclusion - The human consumption of animal products derived from animals that have inadvertently ingested sludge-amended soils may pose a risk of cancer to humans, except for adults when sludge containing typical concentrations of HCBD is applied. 4. Index of Human Cancer Risk from Soil Ingestion (Index 12) a. Explanation - Calculates the amount of pollutant in the diet of a child who ingests soil (pica child) amended with sludge. Compares this amount with RSI. b. Assumptions/Limitations - Assumes that the pica child consumes an average of 5 g/day of sludge- amended soil. If the RSI specific for a child is not available, this index assumes the RSI for a 10 kg child is the same as that for a 70 kg adult. It is thus assumed that uncertainty factors used in deriving the RSI provide protection for the child, taking into account the smaller body size and any other differences in sensitivity. 3-14 ------- Data Used and Rationale i. Concentration of pollutant in sludge-amended soil (Index 1) See Section 3, p. 3-2. ii. Assumed amount of soil in human diet (DS) Pica child 5 g/day Adult 0.02 g/day The value of 5 g/day for a pica child is a worst-case estimate employed by U.S. EPA's Exposure Assessment Group (U.S. EPA, 1983a). The value of 0.02 g/day for an adult is an estimate from U.S. EPA, 1984. iii. Average daily human dietary intake of pollutant (DI) Toddler 0 Ug/day Adult 0 Ug/day See Section 3, p. 3-10. iv. Cancer risk-specific intake (RSI) = 0.90 Ug/day See Section 3, p. 3-10. Index 12 Values Sludge Application Rate (mt/ha) Group Toddler Adult Sludge Concentration Typical Worst Typical Worst 0 0.0 0.0 0.0 0.0 5 0.0042 0.11 0.000016 0.00044 50 0.041 1.1 0.00016 0.0043 500 0.33 8.9 0.0013 0.036 e. Value Interpretation - Same as for Index 9. f. Preliminary Conclusion - Inadvertent ingestion of sludge-amended soil is not expected to pose a cancer risk to humans expect possibly for toddlers ingesting soil amended with sludge containing high concentrations of HCBD at high application rates (50 and 500 mt/ha). 3-15 ------- 5. Index of Aggregate Human Cancer Risk (Index 13) a.. Explanation - Calculates the aggregate amount of pollutant in the human diet resulting from pathways described in Indices 9 to 12. Compares this amount with RSI. b. c. d. e. f. II. LANDPILLING Assumptions/Limitations - As described for Indices 9 to 12. Data Used and Rationale - As described for Indices 9 to 12. Index 13 Values - Values were not calculated due to lack of data. Value Interpretation - Same as for Index 9. Preliminary Conclusion - Conclusion was not drawn because index values could not be calculated due to lack of data. Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. III. INCINERATION Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. IV. OCEAN DISPOSAL Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. 3-16 ------- SECTION 4 PRELIMINARY DATA PROFILE FOR HEXACHLOROBUTADIENE . IN MUNICIPAL SEWAGE SLUDGE I. OCCURRENCE A. Sludge 1. Frequency of Detection Observed in 2 of 13 combined sludges for U.S. treatment plants Detected in 1 of 937 sludge samples from 50 POTWs Detected in 1 of 217 samples from 25 POTWs in Michigan 2. Concentration Values obtained from a study that combined the results of several POTW surveys, including U.S. EPA (1982) and Michigan survey (Jacobs and Zabik, 1983), for a total of 105 detections at 276 POTWs: Weighted mean Overall minimum Overall maximum 0.3 Ug/g DW 9.24 x 10~5 Ug/g DW 8.0 Ug/g DW 338 ug/L WW median, 10 to 675 Ug/L WW range; 4.3 Ug/g DW median, 0.52 to 8.0 Ug/g range in combined sludges from 13 POTWs 2,700 Ug/L for 1 sample Concentrations in 103 of 217 sludges from MI POTWs: Minimum 9.24 (10~5) Ug/g DW Maximum 3.74 Ug/g DW Mean 0.224 Ug/g DW Median 0.0355 Ug/g DW Naylor and Loehr, 1982 (p. 20) U.S. EPA, 1982 (p. 42) U.S. EPA, 1983b (p. A-14) COM, 1984 (p. 8) Naylor and Loehr, 1982 (p. 20) U.S. EPA, 1982 (p. 42) Jacobs and Zabik, 1983 (p. 425) 4-1 ------- B. Soil - Unpolluted 1. Frequency of Detection Data not immediately available. 2. Concentration Concentration of HCBD found in soils sampled at various chlorinated hydrocarbon plants ranged from unde- tected (0) to 980 ug/g C. Hater - Unpolluted 1. Frequency of Detection Either hexachlorobutadiene or hexachlorobenzene was detected in every water sample taken from the lower Mississippi River between Baton Rouge and New Orleans (1975 data). Detected in drinking water from 1 of 10 cities in 1975 2. Concentration Freshwater U.S. EPA, 1976 (p. 60-61) a b. <0.7 to 1.5 Ug/L in waterways near Mississippi River <0.7 to 1.9 Ug/L in lower Mississippi River (1975 data) Seawater Data not immediately available. Drinking water 1.9 to 4.7 Ug/L in drinking "water from Louisiana 0.07 Ug/L highest level found in finished water <0.01 ug/L from 1 city in 1975 Laska et al., 1976 (p. 539) U.S. EPA, 1980 (p. C-l) Laska et al., 1976 (p. 539) U.S. EPA, 1980 (p. A-l) NAS, 1977 (p. 799) U.S. EPA, 1980 (p. C-l) 4-2 ------- D. Air 1. Frequency of Detection Data not immediately available. 2. Concentration <0.5 Ug/m3 in air near chlorohy- U.S. EPA, 1980 drocarbon plants (p. C-4) E. Pood 1. Total Average Intake Data not immediately available. 2. Concentration HCBD contamination is not widespread U.S. EPA, 1980 but localized in areas with raw water (pp« C-l, C-2) sources near industrial plants pro- ducing HCBD. A survey of milk, eggs, and vegetable samples collected near chlorohydrocarbon plants resulted in samples with no measurable HCBD. HCBD concentrations in foodstuffs U.S. EPA, 1980 from other countries: (p. C-3) England: Fresh Milk 0.08 ng/g Imported grapes 3.7 ng/g Tomatoes 0.8 ng/g Germany: Evaporated milk 4 ng/g Egg yolk • 42 ng/g Vegetable oil 33 ng/g II. HUMAN EFFECTS A. Ingestion 1. Carcinogenicity a. Qualitative Assessment Evidence of carcinogenesis U.S. EPA, 1980 (renal carcinoma) (p. C-35) 4-3 ------- b. Potency Cancer potency = U.S. EPA, 1980 7.75 x 10~2 (mg/kg/day)"1 based (p. C-35) on rat study c. Effects Renal tubular adenoma and U.S. EPA, 1980 carcinoma 2. Chronic Toxicity Data not assessed since evaluation based on carcinogenicity 3. Absorption Factor • Data not assessed since evaluation based on carcinogenicity B. Inhalation Data not immediately available. III. PLANT EFFECTS Data not immediately available. IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS A. Toxicity See Table 4-1. B. Uptake See Table 4-2. 2.78 bioconcentration factor for consumption U.S. EPA, 1980 of 6.5 g/day of fish and shellfish (p. C-3) V. AQUATIC LIFE EFFECTS Data not immediately available. VI. SOIL BIOTA EFFECTS Data not immediately available. VII. PHYSICOCHEMICAL DATA FOR ESTIMATING FATE AND TRANSPORT Molecular weight: 261 Solubility: 5 Ug/L at 20°C Vapor pressure: 22 mm Hg at 100°C Specific gravity: 1.675 4-4 ------- TABLE 4-1. TOXICITY OF HEXACHLOROBUTADIENE TO DOMESTIC ANIMALS AND WILDLIFE Species Rat Rat Guinea pig Mice Rat Rat Japanese quail Rat Rat Rat Rat Rat Chemical Form Fed HCBD HCBD HCBD HCBD HCBD HCBD HCBD HCBD HCBD HCBD HCBD HCBD Peed Water Daily Concentration Concentration Intake Duration (pg/g) (mg/L) (rag /kg) of Study Effects NRa • NR 250-350 NR Acute oral toxicity NR NR 20 2 years Renal neoplasms NR NR 90 NR LD50 NR NR 87-116 NR LD50 1-30 NR NR NR No effect 30-100 NR NR NR Renal toxicity 30 NR 5 NR No effect NR NR 2-20 90 days Kidney alteration NR NR NR Lifetime Significant growth reduction NR NR 0.2 Lifetime No effect NR NR 2.0 Lifetime Slight renal toxicity NR NR 2.0 Lifetime Multiple toxic effects References Berndt and Mehendale, 1979 (p. 56) U.S. EPA, 1980 Kociba et al., (p. 589) Kociba et al., (p. 589) Kociba et al., (p. 589) Kociba et al., (p. 589) Kociba et al., (p. 590) Kociba et al., (p. 590) Kociba et al . , (p. 592) Kociba et al., (p. 589) Kociba et al., (p. 589) Kociba et al., (p. 589) (p. C-5) 1977 1977 1977 1977 1977 1977 1977 1977 1977 1977 NR = not reported ------- TABLE 4-2. UPTAKE OF HEXACHLOROBUTADIENE BY DOMESTIC ANIMALS AND WILDLIFE Range of Feed Chemical Concentration (N)a Species Porn Fed (fg/g DW) Rat HCBD 2-4 (2) i Tissue Tissue Concentration Analyzed (pg/g DW) Uptake Factor0 References Kidney fat 7C 1.75-3.5 U.S. EPA, 1980 (p. C-4) aH = Number of feed rates. ^Uptake factor = Tissue concentration DW/feed concentration DU. C7 pg/g for both feed rates. ------- SECTION 5 REFERENCES Berndt, W. 0. and H. M. Mehendale. 1979. Effects of Hexa- chlorobutadiene (HCBD) on Renal Function and Renal Organic Ion Transport in the Rat. Toxicology 14:55-65. Bertrand, J. E., M. C. Lutrick, G. T. Edds and R. L. West. 1981. Metal Residues in Tissues, Animal Performance and Carcass Quality with Beef Steers Grazing Pensacola Bahiagrass Pastures Treated with Liquid Digested Sludge. J. Ani. Sci. 53:1. Boswell, F. C. 1975. Municipal Sewage Sludge and Selected Element Applications to Soil: Effect on Soil and Fescue. J. Environ. Qual. 4(2):267-273. Camp Dresser and McKee, Inc. 1984. A Comparison of Studies of Toxic Substances in POTW Sludges. Prepared for the U.S. EPA under Con- tract No. 68-01-6403. Annandale, VA. August. Chaney, R. L., and C. A. Lloyd. 1979. Adherence of Spray-Applied Liquid Digest Sewage Sludge to Tall Fescue. J. Environ. Qual. 8(3): 407- 411. Jacobs, L. W., and M. J. Zabik. 1983. Importance of Sludge-Borne Organic Chemicals for Land Application Programs. Proc. Sixth Ann. Madison Conf. of Applied Research & Practice on Municipal & Industrial Waste, Sept. 14-15, 1983. Madison, WI. pp. 418-426. Kociba, R. J., D. G. Keys, G. C. Jersey, et al. 1977. Results of a Two-Year Chronic Toxicity Study with Hexachlorobutadiene in Rats. A. Indust. Hyg. Assoc. Journal 38:589-602. Laska, A. L., C. K. Bartell, and J. L. Laseter. 1976. Distribution of Hexachlorobenzene and Hexachlorobutadiene in Water, Soil, and Selected Aquatic Organisms Along the Lower Mississippi River, LA. Bull. Env. Contam. & Toxicol. 15(5)535-542. National Academy of Sciences. 1977. Drinking Water and Health. National Review Council, Safe Drinking Water Committee. Washington, D.C. Naylor, L. M. and R. C. Loehr. 1982. Priority Pollutants in Municipal Sewage Sludge. Biocycle 23(4): 18-22. Pennington, J. A. T. 1983. Revision of the Total Diet Study Food Lists and Diets. J. Am. Diet. Assoc. 82:166-173. 5-1 ------- Ryan, J. A., H. R. Pahren, and J. B. Lucas. 1982. Controlling Cadmium in the Human Food Chain: A Review and Rationale Based on Health Effects. Environ. Res. 28:251-302. Thornton, I., and P. Abrams. 1983. Soil Ingestion - A Major Pathway of Heavy Metals into Livestock Grazing Contaminated Land. Sci.. Total Environ. 28:287-294. U.S. Department of Agriculture. 1975. Composition of Foods. Agri- cultural Handbook No. 8. U.S. Environmental Protection Agency. 1976. Sampling and Analysis of Selected Toxic Substances, Task IB—Hexachlorobutadiene. EPA 560/6-76-015. U.S. Environmental Protection Agency, Washington, D.C. U.S. Environmental Protection Agency. 1980. Ambient Water Quality Criteria for Hexachlorobutadiene. EPA-440/5/80/053. U.S. Environmental Protection Agency, Washington, D.C. U.S. Environmental Protection Agency. 1982. Fate of Priority Pollutants in Publicly-Owned Treatment Works. EPA 440/1-82-303. U.S. Environmental Protection Agency, Washington, D.C. U.S. Environmental Protection Agency. 1983a. Assessment of Human Exposure to Arsenic: Tacoma, Washington. Internal Document. OHEA-E-075-U. Office of Health and Environmental Assessment, Washington, D.C. July 19. U.S. Environmental Protection Agency. 1983b. Process Design Manual for Land Application of Municipal Sludge. EPA 625/1-83-016. U.S. Environmental Protection Agency, Cincinnati, OH. U.S. Environmental Protection Agency. 1984. Air Quality Criteria for Lead. External Review Draft. EPA 600/8-83-028B. Environmental Criteria and Assessment Office, Research Triangle Park, NC. September. 5-2 ------- APPENDIX PRELIMINARY HAZARD INDEX CALCULATIONS FOR HEXACHLOROBUTADIENE IN MUNICIPAL SEWAGE SLUDGE I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING A. Effect on Soil Concentration of Hexachlorobutadiene 1. Index of Soil Concentration (Index 1) a. Formula re (SC x AR) + (BS x MS) CSs " AR + MS CSr = CSS [1 + O where: CSg = Soil concentration of pollutant after a single year's application of sludge .(Ug/g DW) CSr = Soil concentration of pollutant after the yearly application of sludge has been repeated for n •«• 1 years (ug/g DW) SC = Sludge concentration of pollutant (Ug/g DW) AR = Sludge application rate (mt/ha) MS = 2000 mt ha/DW = assumed mass of soil in upper 15 cm BS = Background concentration of pollutant in soil (Ug/g DW) t± = Soil half-life of pollutant (years) n = 99 years b. Sample calculation CS3 is calculated for AR = 0, 5, and 50 mt/ha only n nnn7* „ / nu - (0.3 UR/g DW x 5 mt/ha) + (0 Ug/g DW x 2000 mt/ha) 0.00075 Ug/g DW - (5 mt/ha DW + 2000 mt/ha DW) CSr is calculated for AR = 5 mt/ha applied for 100 years 0.06 yg/g DW = 0.00075 Ug/g DW [1 + 0.5(1/0) + 0.5(2/0) + ... + 0.5(99/0)] A-l ------- B. Effect on Soil Biota and Predators of Soil Biota 1. Index.of Soil Biota Tozicity (Index 2) a. Formula II Index 2 = — where: II = Index 1 = Concentration of pollutant in sludge-amended soil (pg/g DW) TB = Soil concentration toxic to soil biota (Ug/g DW) b. Sample calculation - Values were not calculated due to lack of data. 2. Index of Soil Biota Predator Toxicity (Index 3) a. Formula _ . , II x UB Index 3 = — where: • II = Index 1 = Concentration of pollutant in sludge-amended soil (ug/g DW) UB = Uptake factor of pollutant in soil biota (Ug/g tissue DW [Ug/g soil DW]"1) TR = Feed concentration toxic to predator (ug/g DW) b. Sample calculation - Values were not calculated due to lack of data. C. Effect on Plants and Plant Tissue Concentration 1. Index of Phytotoxic Soil Concentration (Index 4) a. Formula Ii Index 4 = — where: Ij = Index 1 = Concentration of pollutant in sludge-amended soil (ug/g DW) TP = Soil concentration toxic to plants (ug/g DW) A-2 ------- b. Sample calculation - Values were not calculated due to lack of data. 2. Index of Plant Concentration Caused by Uptake (Index 5) a. Formula Index 5 = Ii x UP where: I± = Index 1 = Concentration of pollutant in sludge - amended soil (yg/g DW) UP = Uptake factor of pollutant in plant tissue (pg/g tissue DW [yg/g soil DW]'1) b. Sample Calculation - Values were not calculated due to lack of data. 3. Index of Plant Concentration Increment Permitted by Phytotoxicity (Index 6) a. Formula Index 6 = PP where: PP = Maximum plant tissue concentration associ- ated with phytotoxicity (ug/g D.W) b. Sample calculation - Values were not calculated due to lack of data. Effect on Herbivorous Animals 1. Index of Animal Toxicity Resulting from Plant Consumption (Index 7) a. Formula Index 7 = =-r where: 15 = Index 5 = Concentration of pollutant in plant grown in sludge-amended soil (yg/g DW) TA = Feed concentration toxic to herbivorous animal (yg/g DW) b. Sample calculation - Values were not calculated due to lack of data. A-3 ------- 2. Index of Animal Toxicity Resulting from Sludge Ingestion (Index 8) • a. Formula If AR = 0; Index 8=0 If AR * 0; Index 8 = SC *T^S where: AR = Sludge application rate (mt DW/ha) SC = Sludge concentration of pollutant (ug/g DW) GS = Fraction of animal diet assumed to be soil TA = Feed concentration toxic to herbivorous animal (ug/g b. Sample calculation If AR = 0; Index 8=0 If *H*0 , 0.0005 -••' E. Effect on Humans 1. Index of Human Cancer Risk Resulting from Plant Consumption (Index 9) a. Formula (I5 x DT) + DI Index 9 = where : 15 = Index 5 = Concentration of pollutant in plant grown in sludge-amended soil (pg/g DW) DT = Daily human dietary intake of affected plant tissue (g/day DW) DI = Average daily human dietary intake of pollutant (ug/day) RSI = Cancer risk-specific intake (ug/day) b. Sample calculation (toddler) - Values were not calculated due to lack of data. A-4 ------- 2. Index of Human Cancer Risk Resulting from Consumption of Animal Products Derived from Animals Feeding on Plants (Index 10) a. Formula (15 x UA x DA) + DI Index 10 . RSI where: 15 = Index 5 = Concentration of pollutant in plant grown in sludge-amended soil (ug/g DW) UA = Uptake factor of pollutant in animal tissue (Ug/g tissue DW [ug/g feed DW]'1) DA = Daily human dietary intake of affected animal tissue (g/day DW) (milk products and meat, poultry, eggs, fish) DI = Average daily human dietary intake of pollutant (ug/day) RSI = Cancer risk-specific intake (Ug/day) b. Sample calculation (toddler) - Values were not calculated due to lack of data. 3. Index of Cancer Risk Resulting from Consumption of Animal Products Derived from Animals Ingesting Soil (Index 11) a. Formula If AR = 0; Index 11 = (BS * GS * ^ DA) * DI If AR * 0; Index 11 = (SC x GS x UA JUJA) *_DJL_ where: AR = Sludge application rate (mt DW/ha) SC = Sludge concentration of pollutant (ug/g DW) BS = Background concentration of pollutant in. soil (Ug/g DW) GS = Fraction of animal diet assumed to be soil UA = Uptake factor of pollutant in animal tissue (Ug/g tissue DW [ug/g feed DW]'1) DA = Daily human dietary intake of affected animal tissue (g/day DW) (milk products and meat only) DI = Average daily human dietary intake of pollutant (ug/day) RSI = Cancer risk-specific intake (ug/day) A-5 ------- b. Sample calculation (toddler) 2.298 = [(0.3 pg/g DW x 0.05 x 3.5 pg/g tissue DW (pg/g feed DW)"1 x 39.4 g/day) + 0 pg/day] * 0.90 pg/day 4. Index of Human Cancer Risk Resulting from Soil Ingestion (Index 12) a. Formula (Ii x DS) + DI Index 12 , _ where: II = Index 1 = Concentration of pollutant in sludge-amended soil (pg/g DW) DS = Assumed amount of soil in human diet (g/day) DI = Average daily human dietary intake of pollutant (ug/day) RSI = Cancer risk-specific intake (pg/day) b. Sample calculation (toddler) 0 00417 s (0.00075 yg/g DW x 5 g/day) * 0 yg/day 0.90 ug/day . . 5. Index of Aggregate Cancer Risk (Index 13) a. Formula Index 13 = I9 + I10 + IU + I12 - where: Ig = Index 9 = Index of human cancer risk resulting from plant consumption (unitless) 110 = Index 10 = Index "of human cancer risk resulting from consumption of animal products derived from animals feeding on plants (unitless) 111 = Index 11 = Index of human cancer risk resulting from consumption of animal products derived from animals ingesting soil (unitless) Il2 = Index 12 = Index of human cancer risk resulting from soil ingestion (unitless) DI = Average daily human dietary intake of pollutant (pg/day) RSI = Cancer risk-specific intake (pg/day) A-6 ------- b. Sample calculation (toddler) - Values were not calculated due to lack of data. II. LANDPILLING Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. III. INCINERATION Based on the recommendations of the experts at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. IV. OCEAN DISPOSAL Based on the recommendations of the experts at the OWRS" meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. The U.S. EPA reserves the right to conduct such an assessment for this option in the future. A-7 ------- |