Volume II Chapter 3.0 Pages 2 of 10 page next page 3

3.2.3. Ongoing Regulatory Investigations 3-19

3.3. PUBLICLY OWNED TREATMENT WORKS (POTWs) 3-20

3.3.1. Sources of CDDs/CDFs 3-20

3.3.2. Releases of CDDs/CDFs 3-22

3.4. CHEMICAL MANUFACTURING AND PROCESSING SOURCES 3-25

3.4.1. Manufacture of Halogenated Organic Chemicals - Overview 3-25

3.4.1.1. Chlorophenols 3-25

3.4.1.2. Chlorobenzenes 3-28

3.4.1.3. Chlorobiphenyls 3-33

3.4.1.4. Aliphatic Chlorine Compounds 3-33

3.4.1.5. Dyes and Pigments 3-35

3.2.3. Ongoing Regulatory Investigations

The U.S. EPA is currently under court order to develop revised effluent guidelines (i.e., Best Available Technology and Pretreatment Standards for Existing Sources) for the chemical pulping and bleaching subcategories of the pulp and paper industry. These revised effluent guidelines and standards which address control of CDDs and CDFs from bleached chemical wood pulp and paper mills were proposed by EPA on December 17, 1993 (Federal Register, 1993a).

In addition, the Clean Air Act Amendments of 1990 require EPA to promulgate Most Achievable Control Technology (MACT) standards for hazardous air pollutants from this industry by 1997. To that end, the Office of Air and Radiation, in coordination with the Office of Water, proposed control technology standards for non-combustion sources on December 17, 1993, (Federal Register, 1993a) and will propose control technology standards for combustion sources by October 1994 with promulgation of both by September 1995 (U.S. EPA, 1992d).

Based on the results of an in-depth risk assessment, EPA's Office of Solid Waste concluded that dioxin contained in pulp and paper mill sludges does not pose an unreasonable probability of adverse effects on human health and the environment when disposed in landfills and surface impoundments and that further regulation of these facilities under Subtitle D of the Resource Conservation and Recovery Act (RCRA) to reduce potential dioxin-related risks was not warranted (U.S. EPA, 1991a).

However, EPA did find that improper land application of pulp and paper mill sludge for soil conditioning purposes can pose a significant risk to wildlife. In 1991, EPA proposed a regulation under the Toxic Substances Control Act (TSCA) to limit the concentration of CDDs/CDFs in soil conditioned with sludge and also to establish site management practices for land application of the sludge. EPA deferred finalizing the rule until issuance of the final integrated regulations for effluent guidelines and MACT standards.

These regulations could make TSCA rulemaking unnecessary. In the interim, EPA is negotiating a voluntary agreement with the American Forest and Paper Association to establish CDD/CDF standards and management practices for the use of sludge as a conditioner (U.S. EPA, 1993b).

3.3. PUBLICLY OWNED TREATMENT WORKS (POTWs)

3.3.1. Sources of CDDs/CDFs

CDD/CDFs have been measured in sewage sludge, though the origins have not been well established. In fact, Oberg et al. (1992) reported that low levels of HpCDDs and OCDD are formed, probably as a result of microbial action, in aerated sewage sludge spiked with pentachlorophenol. Potential sources of the CDD/CDFs include industrial inputs, runoff to sewers from lands or urban surfaces contaminated by product uses or deposition of emissions from combustion sources, household wastewater, chlorination operations within the wastewater treatment facility, or a combination of all the above (Rappe, 1992a; Rappe et al., 1989; Horstmann et al., 1992).

The major source(s) for a given treatment plant is likely to be site-specific. For example, Rieger and Ballschmiter (1992) traced the origin of CDDs and CDFs found in municipal sewage sludge in Ulm, Germany, to metal manufacturing and urban sources. The characteristics of both sources were similar and suggested generation via thermal processing. The presence of CDD/CDFs in sewage sludge suggests that CDD/CDFs may also be present in the wastewater effluent discharges of POTWs; however, no published studies reporting the results of effluent analyses for CDD/CDFs could be found.

In a series of recent studies, Horstmann et al. (1992; 1993a; 1993b) and Horstmann and McLachlan (1994) demonstrated that wastewater from household washing machines could be the major source at many, if not all, POTWs that serve primarily residential populations. Horstmann et al. (1992) provided initial evidence that household wastewater could be a significant source. Horstmann et al. (1993a) measured CDD/CDF levels in the effluent from four different loads of laundry from two different domestic washing machines. The concentrations of total CDD/CDF in the four samples ranged from 3,900 to 7,100 pg/L and were very similar in congener profile with OCDD being the dominant congener followed by the hepta- and hexa-CDDs.

Based on the similar concentrations and congener profiles found, Horstmann et al. (1993a) concluded that the presence of CDD/CDF in washing machine wastewater is widespread. A simple mass balance performed using the results showed that the CDD/CDFs found in the four washing machine wastewater samples could account for 27 to 94 percent of the total CDD/CDF measured in the sludge of the local wastewater treatment plant (Horstmann and McLachlan, 1994).

Horstmann et al. (1993a) also performed additional experiments that showed that detergents, commonly used bleaching agents, and the washing cycle process itself were not responsible for the observed CDD/CDFs. Rappe and Andersson (1992) had previously reported that wastewater from clothing and dish washing machines in which sodium hypochlorite-containing detergents were used contained low levels of CDD/CDFs.

To determine if the textile fabric or fabric finishing processes could account for the observed CDD/CDFs, Horstmann et al. (1993b) analyzed the CDD/CDF content of eight different raw (unfinished) cotton cloths containing fiber from different countries and five different white synthetic materials (acetate, viscose, bleached polyester, polyamide, and polyacrylic). The maximum concentrations found in the textile fabrics were 30 ng/kg in the cotton products and 45 ng/kg in the synthetic materials.

Also, a cotton finishing scheme was developed in which one of the cotton materials was subjected to a series of 16 typical cotton finishing processes; one sample was analyzed following each step. The fabric finishing processes showing the greatest effect on CDD/CDF concentration were the application of an indanthrene dye and the "wash and wear" finishing process which together resulted in a CDD/CDF concentration of about 100 ng/kg. Based on the concentrations found, the authors concluded that neither unfinished new fabrics nor common cotton finishing processes can explain the CDD/CDF levels found in wastewater.

Horstmann and McLachlan (1994) analyzed 35 new textile samples, primarily cotton products, for CDD/CDFs. Low levels were found in many cases (total CDD/CDF less than 50 ng/kg). However, several colored T-shirts from a number of clothing producers had extremely high levels, with concentrations up to 290,000 ng/kg. Because the concentrations in identical T-shirts purchased at the same store varied by up to a factor of 20, the authors concluded that the source of CDD/CDFs is not a textile finishing process because a process source would have resulted in a more consistent level of contamination.

Horstmann and McLachlan (1994) conducted additional experiments that demonstrated that the small percentage of clothing items with high CDD/CDF levels could be responsible for the quantity of CDD/CDFs observed in household wastewater and sewage sludge. They were able to demonstrate that the CDD/CDFs can be gradually removed from the fabric during washing, can be transferred to the skin and subsequently transferred back to other textiles and then washed out, or can be transferred to other textiles during washing and then removed during subsequent washings.

3.3.2. Releases of CDDs/CDFs

EPA conducted the National Sewage Sludge Survey in 1988 to obtain national data on sewage sludge quality and management. As part of this survey, EPA analyzed sludges from 175 POTWs for CDD/CDF content; sludges from 15 of the POTWs had detectable levels of 2,3,7,8-TCDD. All sludges had detectable levels of at least one CDD/CDF congener (Rubin and White, 1992). TEQ concentrations ranged from 0.7 to 1,816 ng TEQ/kg dry weight. If all not detected values are assumed to be zero, then the mean and median concentrations are 50 and 9 ng TEQ/kg, respectively. If the not detected values are set equal to the detection limit, then the mean and median concentrations are 86 and 50 ng TEQ/kg, respectively (Rubin and White, 1992).

Approximately 5.4 million dry metric tons of sewage sludge are estimated by EPA to be generated annually in the United States (Federal Register, 1993b). Table 3-5 lists the volume of sludge disposed annually by use and disposal practices. Table 3-5 also lists the estimated amount of TEQs that may be present in sewage sludge and potentially be released to the environment. These values were estimated using the mean TEQ concentration value (not detected values assumed to be zero) reported by Rubin and White (1992) (i.e., 50 ng TEQ/kg). Multiplying this mean concentration by the sludge volumes generated, yields an annual potential total release of 208 grams of TEQ for nonincinerated sludges. Of this 208 grams of TEQ, 3.6 grams enter commerce as a product for distribution and marketing. The remainder is applied to land or is landfilled.

This release estimate is assigned a H/H confidence rating indicating high confidence in both the production and emission factor estimates. The high rating was based on the judgement that the 175 tested facilities were reasonably representative of the variability in the POTW technologies and sewage characteristics. Based on this high confidence rating, the estimated range of potential annual emissions is assumed to vary by a factor of 2 between the low and high ends of the range. Assuming that the best estimate of annual emission to land (105 g TEQ/yr) is the geometric mean of this range, then the range is calculated to be 145 to 290 g TEQ/yr.

Assuming that the best estimate of 3.6 g TEQ annual emissions in product (i.e., the fraction of sludge that is distributed and marketed as a product) is the geometric mean of the range, then the range is calculated to be 2.5 to 5.0 g TEQ/yr.

table Table 3-5Quantity of Sewage Sludge Disposed Annually by Primary,Secondary, or Advanced Treatment POTWs and Potential Dioxin TEQ Releases
An additional 10 to 52 grams of TEQ (central estimate of 23 g TEQ/yr) are estimated to be released to the atmosphere annually by the incineration of sewage sludge.

The basis of these incineration release estimates is presented in Section 3.6.5.

It is interesting to note that CDDs and CDFs detected in ambient air in Ohio have been linked to sewage sludge combustion (Edgerton et al., 1989).

In this study, total CDD/CDF in ambient air ranged from 1,900 to 9,900 fg/m3; no 2,3,7,8-TCDD was detected in any of the samples with a detection limit of less than 240 fg/m3.
expand Table V2 3-5

3.4. CHEMICAL MANUFACTURING AND PROCESSING SOURCES

3.4.1. Manufacture of Halogenated Organic Chemicals - Overview

Several chemical production processes have been shown to generate CDDs and CDFs (Versar, 1985; Hutzinger and Fiedler, 1991a). CDDs and CDFs can be formed during the manufacture of chlorophenols, chlorobenzenes, and chlorobiphenyls (Versar, 1985; Ree et al., 1988). Consequently, disposal of industrial wastes from manufacturing facilities producing these compounds may result in the release of CDDs and CDFs to the environment. Also, the products themselves may contain these compounds, and when used/consumed, may result in additional releases to the environment. CDD and CDF congener distribution patterns indicative of noncombustion sources have been observed in sediments in southwest Germany and the Netherlands.

The congener patterns found suggest that wastes from the production of chlorinated organic compounds may be important sources of CDD and CDF contamination in these regions (Ree et al., 1988). The production and use of many of the chlorophenols, chlorophenoxy herbicides, and PCB products have been banned or strictly regulated in most countries. However, these products may have been a source of the environmental contamination that occurred prior to the 1970s and may continue to be a source of environmental releases based on limited use and disposal conditions (Rappe, 1992a).

3.4.1.1. Chlorophenols

The two major manufacturing processes used to produce chlorophenols include:
(1) electrophilic chlorination of phenol by chlorine gas in the presence of catalytic amounts of aluminum chloride and organic chlorination promoters and stabilizers; and
(2) alkaline hydrolysis of chlorobenzenes using aqueous methanolic sodium hydroxide and heat (Ree et al., 1988). CDD and CDF formation is promoted by the high temperatures and/or alkaline conditions used in these processes. CDDs and CDFs may be formed by nucleophilic substitution, radical reactions, and pyrolysis mechanisms (Versar, 1985; Ree et al., 1988). The major CDD/CDF congeners generated by chlorophenol manufacture are the hexa- through octa-chlorinated congeners (Versar, 1985).

The concentrations of CDD/CDFs in chlorophenols analyzed in the 1970s and early 1980s were assembled and summarized by Versar (1985) and Hutzinger and Fiedler (1991a). Hagenmaier and Brunner (1987) reported the results of analyses of four pentachlorophenol products commercially available during the late 1980s; the total TEQ concentrations in these four products ranged from 0.08 to 2.32 mg/kg. Table 3-6 presents a summary of the data from these three studies.

No more recent data on concentrations of CDDs and CDFs in chlorophenols could be found in the literature. However, the mono- through tetra- substituted chlorophenols and bromophenols are subject to reporting under the Dioxin/Furan Test Rule (discussed in Section 3.4.2) and/or the Dioxin/Furan Pesticide Data Call-In. (See Section 3.4.3.) CDDs and CDFs have also been found in numerous chlorophenol-based biocides according to Versar (1985) and Hutzinger and Fiedler (1991a). (See Section 3.4.3 for information on current EPA efforts to obtain data on contamination levels in pesticides.)

Several studies have provided evidence of localized environmental contamination resulting from the production or use of chlorophenols. For example, Tong et al. (1990) observed that sediment samples collected from a site near a chemical manufacturing facility where 2,4,5-T had been synthesized were highly contaminated with CDDs and CDFs. In addition, the CDD and CDF congener distribution pattern in the sediment was similar to that of 2,4,5-T, suggesting the manufacture found in 2,4,5-T as a primary source of contamination.

As indicated in Table 3-6, pentachlorophenol (PCP) products have been reported to be the most contaminated chlorophenol products. The major congener found in PCP is OCDD, but lower chlorinated congeners are also found (Rappe et al., 1987; Hutzinger and Fiedler, 1991a).

table Table 3-6Concentration Ranges of CDD/CDF Homologue Groups inChlorophenolsa(ppm)
High levels of CDD/CDFs have also been found in sludges from the production of PCP (Versar, 1985; Hutzinger and Fiedler, 1991a). McKee et al. (1990) surveyed harbor sediments adjacent to a wood preserving plant in Ontario, Canada, that uses PCP and creosote. Sediments were contaminated with hexa-, hepta-, and octa-chlorinated CDD/CDFs.
The highest levels observed were:

5.7 ng/g HxCDD, 320 ng/g
HpCDD, 980 ng/g OCDD, 6.5 ng/g HxCDF, and 53 ng/g HpCDF for a site 13 meters from the facility's dock and 400 ng/g OCDF for a site 78 meters from the dock. CDD/CDFs have also been found in composts from a yard waste composting facility in the United Kingdom (Harrad et al., 1991).
expand Table V2 3-6

Past use of PCP-based biocides was suggested as the major source of contamination, based on isomer patterns and empirical evidence. In the mid-1980s, EPA's Office of Solid Waste promulgated land disposal restrictions on wastes (i.e., wastewaters and non-wastewaters) resulting from the manufacture of chlorophenols (40 CFR 268). Table 3-7 lists all solid wastes in which CDDs and CDFs are regulated as hazardous constituents by EPA, including chlorophenol wastes. The regulations prohibit the land disposal of these wastes until they have been treated to a level below the routinely achievable detection limit of 1 ppb in the waste extract for each of the following congener groups: TCDDs, PeCDDs, HxCDDs, TCDFs, PeCDFs, and HxCDFs (standards for waste code F039 apply only to TCDDs and TCDFs). The treatment standard of 1 ppb is based on incineration to 99.9999 percent destruction and removal efficiency. Section 3.4.3 of this report describes regulatory actions taken by EPA to control the manufacture and use of chlorophenol-based pesticides.

EPA's Office of Water has promulgated effluent limitations for facilities that manufacture chlorinated phenols and discharge treated wastewater (40 CFR 414.70).

Although these effluent limitations do not specifically address CDDs and CDFs, the treatment processes required to control the chlorinated phenols that are regulated (2-chlorophenol and 2,4,-dichlorophenol) are expected to control releases of CDDs and CDFs to minimal levels.

The effluent limitations for the individual regulated chlorinated phenols are less than or equal to 39 g/l for facilities that utilize biological end-of-pipe treatment.

3.4.1.2. Chlorobenzenes

Chlorobenzenes are manufactured by electrophilic substitution reactions of gaseous chlorine and benzene (Ree et al., 1988). CDD/CDFs may form during the production of these chemicals, but with less probability than in chlorophenol manufacturing (Hutzinger and Fiedler, 1991a). CDD/CDFs form by nucleophilic substitution and pyrolysis mechanisms (Ree et al., 1988).

The factors contributing to the production of CDD/CDFs are:

(1) using oxygen as a nuclear substituent;
(2) producing or purifying the substance under alkaline conditions; and
(3) using reaction temperatures above 150 C (Hutzinger and Fiedler, 1991a).

Table 3-7Summary of Specific Dioxin-Containing Wastes That Must Complywith Land Disposal Retrictions
table Page 1 of 2 table Page 2 of 2
expand Table V2 3-7 pg 1 of 2 expand table Table V2 3-3-7 pg 2 of 2
The concentrations of CDD/CDFs found in single samples of chlorobenzenes by researchers in Germany (Hagenmaier and Brunner, 1987; Hutzinger and Fiedler, 1991a) are listed in Table 3-8. In di-, tri-, tetra-, and penta-chlorobenzene, CDD/CDFs have been detected in the sub-g/kg range. In hexachlorobenzene, CDD/CDFs have been detected in the g-mg/kg range. No more recent data on concentrations of CDDs and CDFs in chlorobenzenes could be found in the literature.

The limited available published information on CDD/CDF concentrations in chlorobenzene products is not sufficient in quantity (i.e., number of samples) or in detail (i.e., congener-specific results) to enable a reliable estimate to be made of the mass of CDDs/CDFs present in chlorobenzene products even though reliable annual production volume information is available for some products (e.g., 107,526 metric tons of monochlorobenzene and 63,104 metric tons of dichlorobenzene were produced in the United States in 1990) (U.S. ITC, 1991). However, the mono-, di-, and trichlorobenzenes are subject to reporting under the Dioxin/Furan Test rule (Section 3.4.2) and/or the Dioxin/Furan Pesticide Data Call-In (Section 3.4.3).

EPA's Office of Solid Waste has promulgated land disposal restrictions on wastes (i.e., wastewaters and non-wastewaters) resulting from the manufacture of chlorobenzenes (40 CFR 268). Table 3-7 lists all solid wastes in which CDDs and CDFs are regulated as hazardous constituents by EPA, including chlorobenzene wastes. The regulations prohibit the land disposal of these wastes until they have been treated to a level below the routinely achievable detection limit of 1 ppb in the waste extract for each of the following congener groups: TCDDs, PeCDDs, HxCDDs, TCDFs, PeCDFs, and HxCDFs (standards for waste code F039 apply only to TCDDs and TCDFs). The treatment standard of 1 ppb is based on incineration to 99.9999 percent destruction and removal efficiency.

table Table 3-8CDD/CDF Concentrations in Chlorobenzenes
EPA's Office of Water has promulgated effluent limitations for facilities that manufacture chlorinated benzenes and discharge treated wastewater (40 CFR 414.70).

Although these effluent limitations do not specifically address CDDs and CDFs, the
treatment processes required to control the chlorinated benzenes that are regulated (chlorobenzene; 1,2-dichlorobenzene; 1,3-dichlorobenzene; 1,4-dichlorobenzene; 1,2,4-trichlorobenzene; and hexachlorobenzene) are expected to control releases of CDDs and CDFs to minimal levels. The effluent limitations for the individual regulated chlorinated benzenes are less than or equal to 77 g/l for facilities that utilize biological end-of-pipe treatment and are less than or equal to 196 g/l for facilities that do not employ biological end-of-pipe treatment.
expand Table V2 3-38

3.4.1.3. Chlorobiphenyls

PCBs are manufactured by the direct chlorination of biphenyl in the presence of a catalyst. HpCDDs, OCDD, and CDFs, particularly the tetra-, penta-, and hexa-chlorinated CDF congeners, have been detected in commercial PCB formulations (Hagenmaier, 1987) However, the production of PCBs in the United States has been banned under TSCA and the use of in-service PCBs has been dramatically reduced. CDFs can be formed from PCBs under pyrolytic conditions, or by nonpyrolytic conditions via chlorine substitutions on the ortho-positions in the PCB molecule (Ree et al., 1988). Combustion of PCB-containing materials in transformers and capacitors may be a source of PCB-associated CDFs. (See Section 3.5.17.)

3.4.1.4. Aliphatic Chlorine Compounds

Aliphatic chlorine compounds are used as monomers in the production of plastics, as solvents and cleaning agents, and as precursors for chemical synthesis (Hutzinger and Fiedler, 1991a). These compounds are produced in large quantities. In 1990, 13.2 million metric tons of chlorinated aliphatic hydrocarbons were produced (U.S. ITC, 1991). The production of 1,2-dichloroethane and vinyl chloride accounted for 85 percent of this total production.

Highly chlorinated CDDs and CDFs (i.e., hexa- to octa-chlorinated congeners) have been found in samples of 1,2-dichloroethane (55 ppb of OCDF), tetrachloroethane (47 ppb of OCDD), and epichlorohydrin (88 ppb of CDDs and 33 ppb of CDFs) (Hutzinger and Fiedler, 1991a). Because no more recent or additional data could be found in the literature to confirm these values, no estimates have been made of the mass of CDDs/CDFs present in these products manufactured annually.

Greenpeace recently issued a report (Greenpeace, 1993) on dioxin emissions associated with the production of ethylene dichloride (EDC) and vinyl chloride monomer (VCM). The Vinyl Institute has responded with a critique of the report (ChemRisk, 1993). Both of these studies are discussed below.

Greenpeace (1993) estimated that plants producing EDC and VCM release 1.8 kg of TEQ/yr to the environment (air, water, and ground combined - possible releases in the final products were not discussed). This estimate was based on an emission factor of 5 to 10 g TEQ/100,000 tons of VCM produced and a worldwide estimate of PVC (and thus VCM) production of 18 million metric tons/yr.

This estimate represents the total emissions from all plants in the world but was based on data from only four European plants. Greenpeace (1993) cited some specific information on CDD/CDF formation or releases from a lengthy list of primary references. While most of the specific data came from studies conducted or sponsored by industry, in no case was the information offered by Greenpeace (1993) complete enough to allow calculation of all process or waste stream-specific emission factors to particular environmental media for a given plant.

European PVC manufacturers claim the emission factor is 0.01 to 0.5 g TEQ/100,000 metric tons of VCM, resulting in global emissions from EDC/VCM production as 0.002 to 0.09 kg TEQ/yr (Miller, 1993). There is no apparent dispute between the industry and Greenpeace regarding the formation of CDDs/CDFs during the production process, nor that some CDDs/CDFs are released to various environmental media. However, both European and U.S. manufacturers strongly dispute the total emission factors used in Greenpeace (1993) in arriving at their estimated total of 1.8 kg TEQ/yr emitted world-wide by the PVC industry.

Greenpeace (1993) cites the same specific monitoring information as industry but argues in several case studies that "diffuse emissions" of products and byproducts containing unspecified amounts of CDDs/CDFs constitute a very significant additional source to several environmental media. This appears to be the only rationale presented by Greenpeace (1993) to justify increasing the overall emission factor of 0.01 to 0.5 g TEQ/100,000 metric tons of VCM produced, which is accepted by European manufacturers, to Greenpeace's 5 to 10 g TEQ/100,000 metric tons.

PVC production in the United States is 4.5 million metric tons per year (ChemRisk, 1993). No data could be found on dioxin levels in waste streams or air emissions from PVC plants in the United States. Applying the worldwide emission factors discussed above to the U.S. PVC industry, gives a range of dioxin emissions of 0.45 to 23 g TEQ/yr (based on the industry emission factors) to 230 to 450 g TEQ/yr (based on the Greenpeace emission factors).

It is unclear whether EDC/VCM/PVC production and emission control methods are sufficiently similar worldwide to know whether these factors should apply in the United States. Considering this unknown and the lack of measurement data in general and for U.S. facilities in particular, this report does not endorse either of these emission estimates nor is an independent emission estimate presented. Also, insufficient information was provided to indicate how these emissions, if present in the United States, would separate among media. Monitoring efforts to collect these data are highly recommended.

EPA's Office of Water has promulgated effluent limitations for facilities that manufacture chlorinated aliphatic chlorine compounds and discharge treated wastewater (40 CFR 414.70). Although these effluent limitations do not specifically address CDDs and CDFs, the treatment processes required to control the chlorinated aliphatic compounds that are regulated (e.g., 68 g/l for 1,2-dichloroethane and 22 g/l for tetrachloroethylene) are expected to control releases of CDDs and CDFs to minimal levels.

3.4.1.5. Dyes and Pigments ...

table Table 3-9CDD/CDF Levels (g/kg) in Dioxazine Dyes and Pigments
... CDD/CDF contamination of dioxazine dyes and pigments available in Canada has been observed (Williams et al., 1992). As shown in Table 3-9, OCDD and OCDF concentrations in the g/g range, and HpCDD, HxCDD, and PeCDD concentrations in the ng/g range were found in Direct Blue 106 dye (3 samples) and Direct Blue 108 dye (1 sample) dyes and Violet 23 pigments (6 samples)(Williams et al., 1992).

Dioxazine pigments (e.g., Violet 23 pigment) and dioxazine dyes (e.g., Direct Blue 106 and 108) are derived from chloranil, which has been found to contain high levels of CDD/CDFs and has been suggested as the source
of contamination among these dyes (Christmann et al., 1989; Williams et al., 1992; U.S. EPA, 1992b).
expand Table V2 3-39

In May 1990, EPA received test results showing that chloranil was heavily contaminated with dioxins; levels as high as 3,065 ppb TEQ were measured (U.S. EPA, 1992b). (See Section 3.4.2 for analytical results.)

Between 1990 and 1992, EPA learned that dioxin TEQ levels in chloranil could be reduced by more than two orders of magnitude (to less than 20 ppb) through manufacturing feedstock and process changes. EPA's Office of Pollution Prevention and Toxics (OPPT) subsequently began efforts to complete an industry-wide switch from use of the contaminated chloranil to low-dioxin chloranil. Although no chloranil is manufactured in the United States, significant quantities are imported. As of June 1993, EPA had negotiated agreements with all chloranil importers and domestic dye/pigment manufacturers known to EPA who use chloranil in their products to switch to low-dioxin chloranil. EPA will issue a significant new use rule (SNUR) under Section 5 of TSCA when U.S. stocks of chloranil with high levels of CDDs/CDFs are depleted. The SNUR will require industry to notify EPA at least 90 days prior to the manufacture, import, or processing, for any use, of chloranil containing total CDDs/CDFs at a concentration greater than 20 ug/kg (Cash, 1993; U.S. EPA, 1993c).

CDD/CDFs (tetra-, penta-, and hexa-chlorinated congeners) in the ppt range were found in Ni-phthalocyanine when several commercial phthalocyanine dyes were analyzed (Hutzinger and Fiedler, 1991a). Phthalocyanine dyes and diarylide yellow pigments have also been observed to contain PCBs in the ppm range. The PCBs are believed to be generated during manufacture because of the use of high-boiling chlorinated aromatic solvents (Hutzinger and Fiedler, 1991a). EPA, however, has prohibited the processing or distribution in commerce of any diarylide and phthalocyanine pigments that contain 50 ppm or more of PCBs (40 CFR 762.20).