United States Environmental Protection Agency Office of Water Regulations and Standards Washington, DC 20460 Water June, 1985 Environmental Profiles and Hazard Indices for Constituents of Municipal Sludge: Benzidine ------- 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 antl 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 OF CONTENTS Page 1. INTRODUCTION 1-1 2. PRELIMINARY CONCLUSIONS FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE 2-1 Landspreading and Distribution-and-Marketing 2-1 Landfilling 2-1 Incineration 2-1 Ocean Disposal 2-1 3. PRELIMINARY HAZARD INDICES FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE 3-1 Landspreading and Distribution-and-Marketing 3-1 Landf illing 3-1 Incineration 3-1 Ocean Disposal 3-1 Index of seawater concentration resulting from initial mixing of sludge (Index 1) 3-1 Index of seawater concentration representing a 24-hour dumping cycle (Index 2) 3-5 Index of toxicity to aquatic life (Index 3) 3-6 Index of human cancer risk resulting from seafood consumption (Index 4) 3-8 4. PRELIMINARY DATA PROFILE FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE ; 4-1 Occurrence 4-1 Sludge 4-1 Soil - Unpolluted 4-1 Water - Unpolluted 4-1 Air 4-2 Food 4-2 Human Effects 4-2 Ingestion 4-2 Inhalation 4-2 ------- TABLE OF CONTENTS (Continued) Page Plant Effects 4-3 Domestic Animal and Wildlife Effects 4-3 Toxicity 4-3 Uptake 4-4 Aquatic Life Effects 4-4 Toxicity (water concentration causing) 4-4 Uptake 4-4 Soil Biota Effects 4-4 Physicochemical Data for Estimating Fate and Transport 4-5 5. REFERENCES 5-1 APPENDIX. PRELIMINARY .HAZARD INDEX CALCULATIONS FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE A-l 111 ------- 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. Benzidine was initially identified as being of potential concern when sludge is ocean disposed."' This profile is a compilation of information that may be useful in determining whether benzidine poses an actual hazard to human health or the environment when sludge is disposed of by these methods. 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 •* seawater •* marine organisms •* 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 ocean disposal 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 (OWRS) to discuss landspreading, landfilling, incineration, and ocean disposal, respectively, of municipal sewage sludge. 1-1 ------- SECTION 2 PRELIMINARY CONCLUSIONS FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE The following preliminary conclusions have been derived from the calculation of "preliminary hazard indices", which represent conservative 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-AND-MARKETING 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. EPA reserves the right to conduct such an assessment for this option in the future. II. LANDFILLING 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. 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. EPA reserves the right to conduct such an assessment for this option in the future. IV. OCEAN DISPOSAL Increases in seawater concentration of benzidine occur when worst concentration sludges are dumped at typical or worst sites (see Index 1). Slight increases of seawater benzidine concentrations occur after a 24-hour dumping cycle (see Index 2). No toxic conditions to aquatic life occur due to the dumping of benzidine-containing sludge (see Index 3). A potential exists for significant human health risk for the case of worst seafood consumption from organisms exposed to the worst benzidine concnetrations dumped at the worst and typical disposal sites (see Index 4). 2-1 ------- SECTION 3 PRELIMINARY HAZARD INDICES FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE I. LANDSPREADING AND DISTRIBUTE ON-AND-MARKETING Based on Che recommendations of Che experts at the OWES meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. EPA reserves the right to conduct such an assessment for this option in the future. II. LANDFILLING Based on the recommendations of the experCs at the OWRS meetings (April-May, 1984), an assessment of this reuse/disposal option is not being conducted at this time. 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 assessmenC of chis reuse/disposal opcion is noC being conducted at this time. EPA reserves the right to conduct such an assessment for this option in the future. IV. OCEAN DISPOSAL For the purpose of evaluating pollutant effects upon and/or subsequent uptake by marine life as a result of sludge disposal, two types of mixing were modeled. The initial mixing or dilution shortly after dumping of a single load of sludge represents a high, pulse concentration to •which organisms may be exposed for short time periods but which could be repeated frequently; i.e., every time a recently dumped plume is encountered. A subsequent addi- tional degree of mixing can be expressed by a further dilution. This is defined as the average dilution occurring when a day's worth of sludge is dispersed by 24 hours of current movement and represents the time-weighted average exposure concentration for organisms in the disposal area. This dilution accounts for 8 to 12 hours of the high pulse concentration encountered by the organisms during 'daylight disposal operations and 12 to 16 hours of recovery (ambient water concentration) during the night when disposal operations are suspended. A.. Index of Seawater Concentration Resulting from Initial Mixing of Sludge (Index 1) 1. Explanation - Calculates increased concentrations in Ug/L of pollutant in seawater around an ocean disposal site assuming initial mixing. 3-1 ------- 2. Assumptions/Limitations - Assumes that the background seawater concentration of pollutant is unknown or zero. The index also assumes that disposal is by tanker and that the daily amount of sludge disposed is uniformly distributed along a path transversing the site and perpendicular to the current vector. The initial dilution volume is assumed to be determined by path length, depth to the pycnocline (a layer separating surface and deeper water masses), and an initial plume width defined as the width of the plume 4 hours after dumping. The seasonal disappearance of the pycnocline is not considered. 3. Data Used and Rationale a. Disposal conditions Sludge Sludge Mass Length Disposal Dumped by a of Tanker Rate (SS) Single Tanker (ST) Path (L) Typical 825 mt DW/day 1600 mt WW 8000 m Worst 1650 mt DW/day 3400 mt WW 4000 m The typical value for the sludge disposal rate assumes that 7.5 x 10^ mt WW/year are available for dumping from a metropolitan coastal area. The conversion to dry weight assumes 4 percent solids by weight. The worst-case value is an arbitrary doubling- of the typical value to allow for potential future increase. The assumed disposal practice to be followed at the model site representative of the typical case is a modification of that proposed for sludge disposal at the formally designated 12-mile site in the New York Bight Apex (City of New York, 1983). Sludge barges with capacities of .3400 mt WW would be required to discharge a load in no less than 53 minutes travel- ing at a minimum speed of 5 nautical miles (9260 m) per hour. Under these conditions, the barge would enter the site, discharge the sludge over 8180 m and exit the site. Sludge barges with capacities of 1600 mt WW would be required to discharge a load in no less than 32 minutes traveling at a minimum speed of 8 nautical miles (14,816 m) per hour. Under these conditions, the barge would enter the site, discharge the sludge over 7902 m and exit the site. The mean path length for the large and small tankers is 8041 m or approximately 8000 m. Path length is assumed to lie perpendicular to the direction of prevailing current flow. For the typical disposal rate (SS) of 825 mt DW/day, it is assumed that this would be accomplished by a mixture of four 3400 mt 3-2 ------- WW and four 1600 me WW capacity barges. The overall daily disposal operation would last from 8 to 12 hours. For the worst-case disposal rate (SS) of 1650 mt DW/day, eight 3400 mt WW and eight 1600 mt WW capacity barges would be utilized. The overall daily disposal operation would last from 8 to 12 hours. For both disposal rate scenarios, there would be a 12 to 16 hour period at night in which no sludge would be dumped. It is assumed that under the above described disposal operation, sludge dumping would occur every day of the year. The assumed disposal practice at the model site representative of the worst case is as stated for the typical site, except that barges would dump half their load along a track, then turn around and dispose of the balance along the same track in order to prevent a barge from dumping outside of the site. This practice would effectively halve the path length compared to the typical site. b. Sludge concentration of pollutant (SC) Worst 12.7 mg/kg DW Benzidine was detected in only 1 percent of the 256 publicly-owned treatment works (POTWs) surveyed throughout the United States. The maximum concentration detected, 12.7 mg/kg DW, is chosen as the worst case; no typical case is available. c. Disposal site characteristics Average current Depth to velocity pycnocline (D) at site (V) Typical 20 m 9500 m/day Worst 5 m 4-320 m/day Typical site values are representative of a large, deep-water site with an area of about 1500 km^ located beyond the continental shelf in the New York Bight. The pycnocline value of 20 m chosen is the average of the 10 to 30 m pycnocline depth range occurring in the summer and fall; the winter and spring disappearance of the pycnocline is not consi- dered and so represents a conservative approach in evaluating annual or long-term impact. The current velocity of 11 cm/sec (9500 m/day) chosen is based on the average current velocity in this area (CDM, 1984b). 3-3 ------- Worst-case values are representative of a near-shore New York Bight site with an area of about 20 km^. The pycnocline value of 5 m chosen is the minimum value of the 5 to 23 m depth range of the surface mixed layer and is therefore a worst-case value. Current velocities in this area vary from 0 to 30 cm/sec. A value of 5 cm/sec (4320 m/day) is arbitrarily chosen to represent a worst-case value (COM, 1984c). Factors Considered in Initial Mixing When a load of sludge is dumped from a moving tanker, an immediate mixing occurs in the turbulent wake of the vessel, followed by more gradual spreading of the plume. .The entire plume, which initially constitutes a narrow band the length of the tanker path, moves more-or-less as a unit with • the prevailing surface current and, under calm conditions, is not further dispersed by the current itself. However, the current acts to separate successive tanker loads, moving each out of .the immediate disposal path before the next load is dumped. Immediate mixing volume after barge disposal is approximately equal to the length of the dumping track with a cross-sectional area about four times' that defined by the draft and width of the discharging vessel (Csanady, 1981, as cited in NOAA, 1983). The resulting plume is initially 10 m deep by 40 m wide (O'Connor and Park, 1982, as cited in NOAA, 1983). Subsequent spreading of plume band width occurs at an average rate of approximately 1 cm/sec (Csanady et al., 1979, as cited in NOAA, 1983). Vertical mixing is limited by the depth of the pycnocline or ocean floor, whichever is shallower. Four hours after disposal, therefore, average plume width (W) may be computed as follows: * W = 40 m + 1 cm/sec x 4 hours x 3600 sec/hour x 0.01 m/cm = 184 m = approximately 200 m Thus the volume of initial mixing is defined by the tanker path, a 200 m width, and a depth appropriate to the site. For the typical (deep water) site, this depth is chosen as the pycnocline value of 20 m. For the worst (shallow water) site, a value of 10 m was chosen. At times the pycnocline may be as shallow as 5 m, but since the barge wake causes initial mixing to at least 10 m, the greater value was used. > 3-4 ------- 5. Index 1 Values (ug/L) Disposal Sludge Disposal Conditions and Rate (mt DW/day) Site Charac- Sludge teristics Concentration 0 825 1650 Typical Worst Worst Worst 0.0 0.0 0.025 0.22 0.025 0.22 6. Value Interpretation - Value equals the expected increase in benzidine concentration in seawater around a disposal site as a result of sludge disposal after initial mixing. 6. Preliminary Conclusion - Increases in seawater concentration of benzidine occur when worst concentration sludges are dumped at the typical or worst sites. B. Index of Seawater Concentration Representing a 24-Hour Dumping Cycle (Index 2) 1. Explanation - Calculates increased concentrations in Ug/L of pollutant in seawater around an .ocean disposal site utilizing a time weighted average (TWA) concentration. The TWA concentration is that which would be experienced by an organism remaining stationary (with respect to the ocean floor) or moving randomly within the disposal vicinity. The dilution volume is determined by the tanker path length and depth to pycnocline or for the shallow water-site, the 10 m effective mixing depth, as before, but the effective width is now determined by cur- rent movement perpendicular to the tanker path over 24 hours. 2. As sumptions /Limitations - Incorporates all of the assump- tions used to calculate. Index 1. In addition, it is assumed that organisms would experience high-pulsed sludge concentrations for 8 to 12 hours per day and then experience recovery (no exposure to sludge) for 12 to 16 hours per day. This situation can be expressed by the use of a TWA concentration of sludge constituent. 3. Data Used and Rationale See Section 3, pp. 3-2 to 3-4. 3-5 ------- 4. Factors Considered in Determining Subsequent Additional Degree of Mixing (Determination of TWA Concentrations) See Section 3, p. 3-5. 5. Index 2 Values (ug/L) Disposal Sludge Disposal Conditions and Rate (rot DW/day) Site Charac- Sludge teristics Concentration 0 825 1650 Typical Worst Worst Worst 0.0 0.0 0.0069 0.061 0.014 0.12 6. Value interpretation - Value equals the effective increase in benzidine concentration expressed as a TWA concentration in seawater around a disposal site experienced by an organism over a 24-hour period. 7. Preliminary Conclusion - Slight increases of seawater benzidine concentrations occur after a 24-hour dumping cycle. C. Index of Toxicity to Aquatic Life (Index 3) Explanation - Compares the effective increased concentra- tion of pollutant in seawater around the disposal site resulting from Che initial mixing of sludge (Index 1) with the marine ambient water quality criterion of the pollutant, or with another value judged protective of marine aquatic life. For benzidine, this value is the criterion that will protect marine aquatic organisms from both acute and chronic toxic effects. Wherever a short-term, "pulse" exposure may occur as it would from initial mixing, it is usually evaluated using the "maximum" criteria values of EPA's ambient water quality criteria methodology. However, under this scenario, because the pulse is repeated several times daily on a long-term basis, potentially resulting in an accumulation of injury, it seems more appropriate to use values designed to be protective against chronic toxicity. Therefore, to evaluate the potential for adverse effects on marine life resulting from initial mixing concentrations, as quantified by Index 1, the chronically derived criteria values are used. 3-6 ------- 2. Assumptions/Limitations - In addition to the assumptions stated for Indices 1 and 2, assumes that all of the released pollutant is available in the water column to move through predicted pathways (i.e., sludge to seawater to aquatic, organism to man). The possibility of effects. arising from accumulation in the sediments is neglected since the U.S. EPA presently lacks a satisfactory method for deriving sediment criteria. 3. Data Used and Rationale a. Concentration of pollutant in seawater around a disposal site (Index 1) See Section 3, p. 3-5. b. Ambient water quality criterion (AWQC) = 2,500 pg/L Water quality criteria for •the toxic pollutants listed under Section 307(a)(l) of the Clean Water Act of 1977 were developed by the U.S. EPA under Section 30A(a)(l) of the Act. These criteria were derived by utilization of data reflecting the resultant environmental impacts and human ^health effects of these pollutants if present in any body of water. The criteria values presented in this assessment are excerpted from the .ambient water quality criteria document for benzidine. Toxicity to freshwater fish and invertebrates occurs at the above concentration of benzidine and would occur at lower concentrations among organisms more sensitive than those tested (U.S. EPA, 1980). As not data are available on marine organisms, it is assumed for the purpose of this study that values are similar for both freshwater and marine aquatic life. 4. Index 3 Values Disposal Sludge Disposal Conditions and Rate (mt DW/day) Site Charac- Sludge teristics Typical Worst Concentration Worst Worst 0 0 0 .0 .0 0 0 825 .000010 .000086 0 0 1650 .000010 .000086 3-7 ------- 5. Value Interpretation - Value equals Che factor by which the expected seawater concentration increase in benzidine exceeds the protective value. A value > 1 indicates that acute or chronic toxic conditions may exist for organisms at the site. 6. Preliminary Conclusion - No toxic conditions occur due to the dumping of benzidine-containing sludge. D. Index of Human Cancer Risk Resulting from Seafood Consumption (Index 4) 1. Explanation - Estimates the expected increase in human pollutant intake associated with the consumption of seafood, a fraction of which originates from the disposal site vicinity, and compares the total expected pollutant intake with the cancer risk-specific intake (RSI) of the pollutant. 2. Assumptions/Limitations - In addition to the assumptions listed for Indices 1 and 2, assumes that the seafood tissue concentration increase can be estimated from the increased water concentration (Index 2) by a bioconcentration factor. It also assumes that, over the long term, the seafood catch from the disposal site vicinity will be diluted to some extent by the catch from uncontaminated areas. 3. Data Used and Rationale a. Concentration of pollutant in seawater around a disposal site (Index 2) See Section 3, p. 3-6. Since biconcentration is a dynamic and reversible process, it is expected that uptake of sludge pollutants by marine organisms at the disposal site will reflect TWA concentrations, as quantified by Index 2, rather than pulse concentrations. b. Dietary consumption of seafood (QF) Typical .14.3 g WW/day Worst 41.7 g WW/day Typical and worst-case values are the mean and the 95th percentile, respectively, for all seafood consumption in the United States (Stanford Research Institute (SRI) International, 1980). 3-8 ------- Fraction of consumed seafood originating from the disposal site (PS) For a typical harvesting scenario, it was assumed that the total catch over a wide region is mixed by harvesting, marketing and consumption practices, and that exposure is thereby diluted. Coastal areas have been divided by the National Marine Fishery Service (NMFS) into reporting areas for reporting on data on seafood landings. Therefore it was convenient to express the total area affected by sludge disposal as a fraction of an NMFS reporting area- The area used to represent the disposal impact area should be an approximation of the total ocean area over which the average concentration defined by Index 2 is roughly applicable. The average rate of plume spreading of 1 cm/sec referred to earlier amounts to approximately 0.9 km/day. Therefore, the "combined plume of all sludge dumped during one working day will gradually spread, both parallel to and perpendicular to current direction, as it proceeds down-current. Since the concentration has been averaged over the direction of current flow, spreading in this, dimension will not further reduce average concentration; only spreading in the perpendicular dimension will reduce the average. If stable conditions are assumed over a period of days, at least 9 days would be required to reduce the average concentration by one-half. At that time, the original plume length of approximately 8 km (8000 m) will have doubled to approximately 16 km due to spreading. It is probably unnecessary to follow the plume further since storms, which would result in much more rapid dispersion of pollutants to background concentrations are expected on at least a 10-day frequency (NOAA, 1983). Therefore, the area impacted by sludge disposal (AI, in km2) at each disposal site will be considered to be defined by the tanker path length (L) times the distance of current movement (V) during 10 days, and is computed as follows: AI = 10 x L x V x 10~6 km2/m2 . (1) To be consistent with a conservative approach, plume dilution due to spreading in the perpendicular direction to current flow is disregarded. More likely, organisms exposed to the plume in the area defined by equation 1 would experience a TWA. concen- tration lower than the concentration expressed by Index 2. 3-9 ------- Next, the value of AI must be expressed as a fraction of an NMFS reporting area. In the New York Bight, which includes NMFS areas 612-616 and 621- 623, deep-water area 623 has an area of approximately 7200 km2 and constitutes approximately 0.02 percent of the total seafood landings for the Bight (CDM, 1984a).' Near-shore area 612 has an area of approximately 4300 km2 and constitutes approximately 24 percent of the total seafood landings (CDM, 1984b). Therefore the fraction of all seafood landings (FSt) from the Bight which could originate from the area of impact of either the typical (deep-water) or worst (near-shore) site can be calculated for this typical harvesting scenario as follows: For the typical (deep water) site: = AI x 0.02% = (2) t 7200 km^ [10 x 8000 m x 9500 m x 10"6 km2/m2] x 0.0002 5 A ~~ ^ • X X J. U 7200 km2 . . For the worst (near shore) site: FSt = ^-J 4300 km2 [10 x 4000 m x 4320 m. x 10"6 km2/m2] x 0.24 _ 3 2— y • u x i u T^VW ~» To construct a worst-case harvesting scenario, it was assumed that the total seafood consumption for an individual could originate from an area more limited than the entire New York Bight. For example, a particular fisherman providing the entire seafood diet for himself or others could fish habitually within a single NMFS reporting area. Or, an individual could have a preference for a particular species which is taken only over a more limited area, here assumed arbitrarily to equal an NMFS reporting area. The fraction of consumed seafood (FSW) that could originate from the area of impact under this worst-case scenario is calculated as follows: For the typical (deep water) site: FSW = AI 0 = 0.11 (4) 7200 km2 3-10 ------- For the worst (near shore) -site: - ^— - 4300 km2 FSW = - — - = O.OAO (5) d. Bioconcentration factor of pollutant (BCF) = 87.5 L/kg The value chosen is the weighted average BCF of benzidine for the edible portion of all freshwater and estuarine aquatic organisms consumed by U.S. citizens (U.S. EPA, 1980). The weighted averate BCF is derived as part of the water quality criteria developed by the U.S. EPA to protect human health from the potential carcinogenic effects of benzidine induced by ingestion of contaminated water and aquatic organisms. The weighted average BCF is calculated by adjusting the mean normalized BCF (steady-state BCF corrected to 1 percent lipid content) to the 3 percent lipid content of consumed fish and shellfish. It should be noted that lipids of marine species differ in both structure and quantity from those of freshwater species. Although a BCF value calculated entirely from marine data would be more appropriate for this assessment, no such data are presently available. e. Average daily human dietary intake of pollutant (DI) = 0 ug/day Although no data are immediately available on DI , a value of 0 ug/day is assumed so that index values can be calculated* f. Cancer potency = 234 (mg/kg/day)~^ The cancer potency value is derived by U.S. EPA (1980) based on studies of bladder cancer in humans. g. Cancer risk— specific intake (RSI) = 2.99 x 10~4 Ug/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: _ IP"6 x 70 kg x 103 Ug/mg Cancer potency 3-11 ------- 4. Index 4 Values Disposal Sludge Disposal Conditions and Rate (mt DW/day) Site Charac- Sludge Seafood teristics Concentration3 Intakea»b 0 825 1650 Typical Worst Typical 0.0 0.00061 0.0012 Worst 0.0 9.3 18 Worst Worst Typical 0.0 2.4 4.9 Worst 0.0 30.0 59 a All possible combinations of these values are not presented. Additional combinations may be calculated using the formulae in the Appendix. 0 Refers to both the dietary consumption of seafood (QF) and the fraction of consumed seafood originating from the disposal site (FS). "Typical" indicates the use of the typical-case values for both of these parameters; "worst" indicates the use of the worst-case values for both. Value Interpretation - Value > 1 indicates a potential increase in -cancer risk of > 10~6 (1 per 1,000,000). Comparison with the null index value at 0 mt/day indicates the degree to which any hazard is due to sludge disposal, as opposed to pre-existing dietary sources. Preliminary Conclusion - A potential exists for significant human health risk for the case of worst seafood consumption from organisms exposed to the worst benzidine concentrations dumped at the worst and typical sites. 3-12 ------- SECTION 4 PRELIMINARY DATA PROFILE FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE I. OCCURRENCE Benzidine and its congeners are used in the industry primarily for the synthesis of azo dyes. U.S. production, and importation of benzidine and benzidine compounds may exceed 3.5 million kilograms per year. Benzidine and its derivatives are not naturally occurring compounds and are not thought to be generally dispersed in the environment. A. Sludge 1. Frequency of Detection Benzidine not detected in influent, effluent, or sludges from 50 POTWs Benzidine detected in 1 percent of 256 POTWs studied 2. Concentration Maximum value 12.7 yg/g DW in 256 POTWs studied B. Soil - Unpolluted "No data were found concerning the distribution of benzidine compounds in soil. Benzidine has been shown to be absorbed to some clays and, because of its physical properties, is probably immobilized rapidly in soils and sediments." C. Water - Unpolluted In the United States, benzidine and its derivatives have been observed in dye manufacturing factory wastes, but not in the drainage areas into which these wastes feed; however, few attempts at actual measurements have been made. Benzidine has not been found to occur in the aquatic environment in the U.S. U.S. EPA, 1982a (p. 36-50) COM, 1984c (p. 8) CDM, 1984c (p. 8) U.S. EPA, 1978 (p. 4) U.S. EPA, 1978 (p. 4) U.S. EPA, 1978 (p. 79) 4-1 ------- A field survey of the Buffalo and Niagara U.S. EPA, 1980 River using the chloraraine-T method (p. C-27) (method is suspect) detected as no benzidine positive samples (Detection Limit = 0.2 ug/L). D. Air No measurements for benzidine in ambient U.S. EPA, 1979 air have been reported. (p. 10) E. Pood Ingestion is not generally an important U.S. EPA, 1980 source of exposure to benzidine. (p. C-l) No data on benzidine in food were found. II. HUMAN EFFECTS A. Ingestion 1. Carcinogenicity a. Qualitative Assessment Data not immediately available. b. Potency Cancer potency = 234 U.S. EPA, 1980 (mg/kg/dayr1 ' (p. C-54) c. Effects Data not immediately available. 2. Chronic Toxicity Data not immediately available. B. Inhalation 1. Carcinogenicity a. Qualitative Assessment Data show that benzidine is a human U.S. EPA, 1980 carcinogen. b. Potency Cancer potency = 234 U.S. EPA, 1980 (mg/kg/dayr1 . - (p. C-54) 4-2 ------- c. Effects Benzidine and its derivatives have U.S. EPA, 1980 ' been shown to produce bladder (p. C-15) cancer after a long period of latency. 2. Chronic Toxicity Data not immediately available. III. PLANT EFFECTS No data are available on benzidine metabolism U.S. EPA, 1978 or effects from benzidine exposure in higher (p. 6) plants. Benzidine has not received much attention in this area since it is not a natural environmental constituent and is not believed to be widely dispersed from industrial sources. IV. DOMESTIC ANIMAL AND WILDLIFE EFFECTS A. Toxicity Rats fed N,N'-diacetylbenzidine and U.S. EPA, 1978 N, N, N1,N'-tetramethylbenzidine at (p. 101) equal molar levels of 0.25% and 0.27% respectively, developed, lipemia and glomerular lesions consisting of fat- filled spaces in the glomerular tuft 2 to 4.5 months after beginning of treatment. Mice fed 0.01%-0.08% benzidine U.S. EPA, 1978 dihydrochloride exhi-bited various toxic (p. 101) symptoms: lost weight in proportion to the dose of benzidine received, decreased weight of liver and kidney with increased dosage, increased thymus weight with increased dosage. Subcutaneous injection of benzidine has U.S. EPA, 1978 produced cancer in mice and rats. (p. 102) Rats fed 0.043% N,N'-diacetylbenzidine U.S. EPA, 1980 developed glomerulonephritis and (p. C-12) nephrotic syndrome. Orally administered benzidine did not U.S. EPA, 1980 produce urinary bladder cancer in dogs. (p. C-17) No tumors were found in female beagle dogs fed 1 rag/kg, 5 days per week for 3 years. 4-3 ------- In hamsters fed benzidine in 0.1% of their U.S. EPA, 1980 diet throughout their life span, extensive (p. C-17) bile duct proliferations and cysts appeared along with cholangiofibrosis, hepatomas, and liver cell carcinoma. It is the metabolites of benzidine that U.S. EPA, 1980 are considered to be the proximate (p. C-17) carcinogens. Benzidine and its salts, without question, U.S. EPA, 1979 are carcinogenic to humans, with the site (p. 11) of tumor induction being the bladder. B. Uptake Benzidine does not appear to be stored or From data concentrated in animal tissue, but is presented in metabolized, with metabolites and free U.S. EPA, 1980 benzidine eliminated in urine (primarily) (p. C-4 to and feces. C-ll) V. AQUATIC LIFE EFFECTS A. Toxicity (Water concentration causing) 1. Freshwater Acute toxicity occurs at concen- U.S. EPA, 1980 trations as low as 2500 Ug/L. _. (p. B-2) Based on tests of one invertebrate and five fish species. 2. Saltwater Data not immediately available. B. Uptake Bioconcentration factor = 87.5 L/kg Based on the edible portion of all U.S. EPA, 1980 freshwater and estuarine aquatic (p. C-3) organisms consumed by U.S. citizens. VI. SOIL BIOTA EFFECTS Benzidine inhibited biooxidation in activated U.S. EPA, 1978 sludges at 500 mg/L, caused some inhibition (p. 74) at 1 to 5 mg/L, and was thought to be oxidized at 0.1 mg/L or less. 4-4 ------- VII. PHYSICOCHEMICAL DATA FOR ESTIMATING FATE AND TRANSPORT Molecular weight: 184.23 Density: 1.250 Melting point: 115° to 120°C (slow heating) 128°C (fast heating) Boiling point: 400°C Soluble in alcohol and ether Slightly soluble in water: 400 mg/L (12°C) Under experimental water waste treatment U.S. EPA, 1978 conditions, air oxidation of benzidine (p. 5) proceeded readily, and there was also some evidence of biological oxidation. Chemical f-ormula: Benzidine is apparently not easily degraded . U.S."EPA, 1980 by the microorganisms in sewage plant sludge (p. A-2) Benzidine half life in water is estimated at U.S. EPA, 1980 100 days (p. C-27) 4-5 ------- SECTION 5 REFERENCES Camp Dresser and McKee, Inc. 1984a. Technical Review of the 106-Mile Ocean Disposal Site. Prepared for U.S. EPA under Contract No. 68- 01-6403. Annandale, VA. January. Camp Dresser and McKee, Inc. 1984b. Technical Review of the 12-Mile Sewage Sludge Disposal Site. Prepared for U.S. EPA under Contract No. 68-01-6403. Annandale, VA. May. Camp Dresser and McKee, Inc. 1984c. A Comparison of Studies of Toxic Substances in POTW Sludges. .Prepared for U.S. EPA under Contract No. 68-01-6403. Annandale, VA. August. City of New York Department of Environmental Protection. 1983. A Special Permit Application for the Disposal of Sewage Sludge from Twelve New York. City Pollution Control Plants at 'the 12-Mile Site. New York, NY. December. NOAA Technical Memorandum NMFS-F NEC-26. 1983. Northeast Monitoring Program 106-Mile Site Characterization Update. U.S. Department of Commerce National Oceanic and Atmospheric Administration. August. Stanford Research Institute International. 1980. Seafood Consumption Data Analysis. Final Report, Task 11. Prepared for U.S. EPA under Contract No. 68-01-3887. Menlo Park, California, September. U.S. Environmental Protection Agency. 1978. Reviews of the Environmental Effects of Pollutants. II. Benzidine. EPA-600/1- 78-024. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1979. Status Assessment of Toxic Chemicals. Benzidine. EPA-600/2-79-210e. Cincinnati, Ohio. U.S. Environmental Protection Agency. 1980. Ambient Water Quality Criteria for Benzidine. EPA 440/5-80-023. Washington, D.C. U.S. Environmental Protection Agency. 1982a. Fate of Priority Pollutants in Publicly-Owned Treatment Works. Volume 1. EPA 440/1-82/303. Washington, D.C. U.S. Environmental Protection Agency. 1982b. Test Methods for Evaluating Solid Waste. SW-846. Washington, D.C. ^ 5-1 ------- APPENDIX PRELIMINARY HAZARD INDEX CALCULATIONS FOR BENZIDINE IN MUNICIPAL SEWAGE SLUDGE I. LANDSPREADING AND DISTRIBUTION-AND-MARKETING 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. EPA reserves the right to conduct such as assessment for this option in the future. II. LANDFILLING 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. EPA reserves the right to conduct such as 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. EPA reserves the right to conduct such as assessment for this option in the future. IV. OCEAN DISPOSAL A. Index of Seawater Concentration Resulting from Initial Mixing of Sludge (Index 1) 1. Formula SC x ST x PS Index 1 = W x D x L where: SC = Sludge concentration of pollutant (mg/kg DW) ST = Sludge mass dumped by a single tanker (kg WW) PS = Percent solids in sludge (kg DW/kg WW) W = Width of initial plume dilution (m) D = Depth to pycnocline or effective depth of mixing for shallow water site (m) L = Length of tanker path (m) 2. Sample Calculation 12.7 mg/kgDW x 1600000 kg WW x 0.04 kg DW/kg WW x 103 ug/mg - — - - - — * -a n 0. , 200 m x 20 m x 8000 m x 103 L/m3 A-l ------- B. Index of Seawater Concentration Representing a 24-hour Dumping Cycle. (Index 2) 1. Formula SS x SC Index 2 = V x D x L where: SS = Daily sludge disposal rate (kg DW/day) SC = Sludge concentration of pollutant (mg/kg DW) V = Average current velocity at site (m/day) D = Depth to pycnocline or effective depth of mixing for shallow water site (m) L = Length of tanker path (m) 2. Sample Calculation ,, /T - 825000 kg DW/day x 12.7 mg/kg DW x 103 Ug/mg ug/L - -> '-* 9500 m/day x 20 m x 8000 m x 10-> C. Index of Toxicity to Aquatic Life (Index 3) 1. Formula IndeX 3 = ATJQC" where: I± = Index 1 = Index of seawater concentration resulting from initial mixing after sludge disposal (ug/L) AWQC = Criterion or other value expressed as an average concentration to protect marine organisms from acute and chronic toxic effects (ug/L) 2. Sample Calculation O.OOOOiO D. Index of Human Cancer Risk Resulting from Seafood Consumption (Index 4) 1. Formula _ , . (I2 x BCF x 10~3 kg/g x FS x QP) + PI Index 4 = - RSI A-2 ------- where: 12 = Index 2 = Index of seawater concentration representing a 24-hour dumping cycle (ug/L) QF = Dietary consumption of seafood (g WW/day) FS = Fraction of consumed seafood originating from the disposal site (unitless) BCF = Bioconcentration factor of pollutant (L/kg) DI = Average daily human dietary intake of pollutant (Ug/day) RSI = Cancer risk-specific intake (ug/day) 2. Sample Calculation 0.00061 = (0.0069ug/L x 87.5L/kg x 10~3kg/g x O.OQ0021 x 14.3gWW/day) * Oug/dav 2.99 x 10"* Ug/day A-3 ------- |