Toolkit for Identification and Quantification of Releases of Dioxins, Furans and Other Unintentional POPs
PART III Annexes
Annex 2 Guidance on Identifying Sources of PCDD/PCDF
More than 80 PCDD/PCDF sources, each with one or more emission factors, are currently listed in the Toolkit. However, new, yet unlisted sources continue to be identified. These sources attest to the variety of materials and conditions that are associated with PCDD/PCDF formation and release. A brief description of the factors that influence PCDD/PCDF formation and release during industrial chemical production and in combustion processes is given in Chapter 1.4 and further addressed in the Guidelines on Best Available Techniques and Provisional Guidance on Best Environmental Practices.
While carbon, hydrogen and oxygen are common to most industrial chemical production processes as well as processes and activities involving combustion, the possibility of PCDD/PCDF formation exists only when chlorine is also present in elemental, organic or inorganic form. This distinguishing characteristic has been used in identifying some of the PCDD/PCDF sources now listed in the Toolkit. For example, Denmark began the process of identifying PCDD/PCDF sources within its chemical manufacturing sector by selecting and then further evaluating processes that involved any form of chlorine (Hansen 2000). In Germany, a similar strategy was followed in identifying PCDD/PCDF sources among industries in North Rhine-Westphalia (Broker et al. 1999) and among thermal processes in the European Union (Wenborn et al. 1999). This strategy can also be followed in identifying new, as-yet unlisted sources as well as hot spots.
PCDD/PCDF source identification can be further refined by the preliminary evaluation shown below, which entails drawing on information in national and regional inventories, national chemical lists, the scientific literature and reports by governments and non-governmental organizations. More in-depth evaluation may also entail assessing the availability of other materials, such as metal catalysts, and conditions, such as temperatures, that are conducive to PCDD/PCDF formation (see, for example, Chapter 1.4 and the BAT&BEP Guidelines, Section VI.F Specific Chemical Production Processes Releasing Chemicals Listed in Annex C) and monitoring gaseous emissions, aqueous discharges, solid residues and products of suspected PCDD/PCDF sources.
Listed in tables III.2.1, III.2.2 and III.2.3 below are industrial chemicals, pesticides and processes or activities that are examples of the potential new sources being reported in the scientific literature, government reports, etc. In their use and/or production some of these may make substantialcontributions to national and regional PCDD/PCDF releases. For example, a recent study found PCDD/PCDF as contaminants in 23 pesticides currently used in Australia and estimated that applications of only one of the pesticides, pentachloronitrobenzene (PCNB), may be Australia’s largest single PCDD/PCDF source (Holt et al. 2010). In addition, preliminary results suggest that post-application photodegradation of PCNB may increase PCDD/PCDF releases by 3 to 4 times (Holt et al. 2010). Production of each of the pesticides in this study is a potential PCDD/PCDF source and, as such, deserves careful attention. It is also useful to note that many other chemicals and pesticides were identified in the past as known, suspected or highly probable PCDD/PCDF sources and some of these are still in production today (see Bejarano 2004).
|Substance||Associated PCDD/PCDF Release|
|Hydrogen chloride (HCl, 7647-01-0) and Hydrochloric acid||A survey of chlorinated chemicals production in the Netherlands found PCDD/PCDF at 0.3 pg I-TEQ/L in HCl (van Hattum et al. 2004). In the U.S., PCDD/PCDF concentrations of 20.8 and 28.1 pg I-TEQ/L were measured in samples of sales-grade aqueous hydrochloric acid that was a secondary product of two EDC/VCM/PVC facilities (Vinyl Institute 2002). HCl was also recently identified as the source of PCDD/PCDF contamination in hydrochloric acid used in gelatin production in Europe (Hoogenboom et al. 2007). Most HCl is produced as a secondary product of about 40 manufacturing processes, so emission factors are necessarily specific to those processes.|
|Sodium hypochlorite (NaOCl, CAS 7681-52-9)||PCDD/PCDF were measured at 4.9 pg TEQ/g in sodium hypochlorite in the only such analysis that was found in the available scientific literature (Rappe 1990). However, contaminated sodium hypochlorite was identified as the source of PCDD/PCDF in sludge from the Swedish textile industry (Lexen 1993).|
|Metal chlorides||PCDD/PCDF were detected in aluminum chloride (AlCl3), cuprous chloride (CuCl2) cupric chloride (CuCl3), and ferric chloride (FeCl3) in 1986 (Heindl 1986). More recently, high concentrations of PCBs, which are common co-contaminants with PCDD/PCDF, as well as polychloro-bromobiphenyls (PXBs), were reported in FeCl3 (Nakano 2007).|
|Acetylene(CAS 74-86-2)||PCDD/PCDF have been reported in wastewater and wastewater treatment sludge from acetylene production by the carbide process. Lee et al. (2009) derived an EFWater of 5.667 ng TEQ/t for this process, and Jin et al.(2009) derived an EFRESIDUE of 126.69 µg TEQ/t. PCDD/PCDF were measured at 17,000 pg-TEQ/L in wastewater from the purification of acetylene using sodium hypochlorite (Kawamoto 2002). PCDD/PCDF formation has been attributed to the presence of chlorine-containing impurities in the lime (CaO) that is heated with coke to produce calcium carbide (Jin et al. 2009) and to the use of a chlorine-based oxidizing agent for purifying the crude acetylene (Kawamoto 2002).|
|Trichloroethylene (CAS 79-01-6)||PCDD/PCDF were reported at a concentration of 0.7 ng TEQ/kg in trichloroethylene made by Solvay in France (van Hattum et al. 2004). PCDD/PCDF have also been found in process residues from trichloroethylene production (Dyke 1997, Wenborn 1999) and in wastewater (Weiss 2006). Trichloroethylene is primarily produced as a secondary product in the production of ethylene dichloride (EDC) by direct chlorination and/or oxychlorination of ethylene.|
|Epichlorohydrin (1-Chloro-2,3-epoxypropane, CAS 106-89-8 )||Production of epichlorohydrin is known to generate large amounts of chlorinated by-products, some of which are released in wastewater and, most probably, in wastewater treatment sludge (Bijsterbosch et al. 1994). PCDD/PCDF have been reported in epichlorohdrin itself and in process wastewater from its production (Fiedler 1994, Lee et al. 2009). Lee et al. (2009) measured PCDD/PCDF in wastewater from an epichlorohydrin production facility in Taiwan and derived an EFWATER of 5.8 ng TEQ/t. Also a PCDD/PCDF concentration of 1.82 ng TEQ/kg in epichlorohydrin was reported by Fiedler (1994).|
|Chloroprene(2-chloro-1,3-butadiene, CAS 126-99-8) and Polychloroprene (Neoprene, CAS 9010-98-4) (Polymer of 2-chloro-1,3-butadiene)||PCDD/PCDF were detected at a concentration of 90 ng TEQ/kg in polychloroprene (Neoprene) produced by a Dutch manufacturer (van Hattum et al. 2004). PCDD/PCDF also occurred at 209 pg TEQ/m³ in vent gases from the same facility, which produced epichlorohydrin, allyl chloride and PVC.|
|Hexachlorocyclohexane (CAS 608-73-1)||PCDD/PCDF were reported in hexachlorocyclohexane (Zheng et al. 2008).|
|Tetrachlorobenzene (CAS 95-94-3)||Production of 1,700 tons of tetrachlorobenzene was associated with release in the product of 17.9 g TEQ/year, which suggests an average PCDD/PCDF content in the tetrachlorobenzene of 10,529 ng TEQ/kg (The People’s Republic of China 2007).|
|Chlorinated PVC (C-PVC, CAS 9002-86-2)||PDCC/PCDF as high as 32,000 ng TEQ/kg have been detected in C-PVC (van der Weiden and van der Kolk 2000).|
|Aromatic polyamides (Aramids) and precursors||PCDD/PCDF were reported at a concentration of 0.137 ng I-TEQ/m³ in process vent gas (van Hattum et al. 2004) and have also been detected in wastewater (van der Weiden and van der Kolk 2000).|
|Chlorinated methanes (methylene chloride, chloroform and carbon tetrachloride)||Data submitted to the U.S. Environmental Protection Agency show detectable levels of PCDD/PCDF are released in wastewater (Weiss 2006).|
|Vinylidene chloride (1,1-dichloroethylene CAS 75-35-4)|
|Polypropylene||U.S. Toxics Inventory shows reportable quantities of PCDD/PCDF are released in wastewater (USEPA 2004).|
|Aliphatic isocyanate resins production|
|Meta diisopropenybenzene production|
|Adhesion polymers production|
|Formaldehyde resins production|
|Hytrel polyester elastomer|
|Copper chromated arsenate|
|PVC-copolymers||PCDD/PCDF were released in vent gases (van der Weiden and van der Kolk 2000).|
|Sodium dichloroisocyanurate (Sodium troclosene, NADCC, CAS 2893-78-9)||PCDD/PCDF were detected at a concentration of 0.6 pg TEQ/g in detergents containing sodium dichloroisocyanurate (USEPA 2000b).|
|Chlorobenzenes||These chemicals are produced by processes where dioxin-like compounds formation is known to occur (Seys 1997).|
|Pesticide||µg TEQ/t active ingredient, except where noted||Reference|
(2RS)-2-(2,4-dichlorophenoxy)propionic acid (CAS 120-36-5)
|Nitrophen (NIP) =
2,4-dichlorophenyl-4’-nitrophenyl ether (CAS 1836-75-5)
|Lindane (γ-hexachlorocyclohexane, γ-HCH)
1α,2α,3β,4α,5α,6β-hexachlorocyclohexane (CAS 58-89-9)
|Holt et al. (2010)|
|Chlorothalonil 2,4,5,6-tetrachloroisophthalonitrile (CAS 1897-45-6)||110b||Holt et al. (2010)|
2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol (CAS 115-32-2)
|84||Li et al. (2009)|
tetrachloroterephthalic acid (CAS 2136-79-0)
|Holt et al. (2010)|
2-Methyl-4-chlorophenoxyacetic acid (CAS 94-74-6)
3,6-Dichloro-2-methoxybenzoic acid (CAS1918-00-9)
|Holt et al. (2010)|
||19.8c||Huwe et al. (2003)|
4-Amino-3,5-dichloro-6-fluoro-2-pyridyloxyacetic acid (CAS 69377-81-7)
|17b||Holt et al. (2010)|
4-(2,4-dichlorophenoxy)butyric acid (CAS 94-82-6)
|Holt et al. (2010)|
|Assure II = Quizalofop P-Ethyl
ethyl (2R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propionate (CAS 100646-51-3)
|4.1||Huwe et al. (2003)|
2-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]-5-methoxymethylnicotinic acid (CAS 114311-32-9)
|Holt et al. (2010)|
2',6'-difluoro-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide (CAS 98967-40-9)
|Holt et al. (2010)|
|MCPA 2-methyl-4-chlorophenoxyacetic acid (CAS 94-74-6)||
|Holt et al. (2010)|
3,5,6-Trichloro-2-pyridinyloxyacetic acid (CAS 55335-06-3)
4-Amino-3,5,6-trichloro-2-pyridinecarboxylic acid (CAS 1918-02-1)
|2.5b||Holt et al. (2010)|
|Mecoprop/Dicamba = (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid (CAS 93-65-2 and CAS 7085-19-0) 3,6-Dichloro-2-methoxybenzoic acid (CAS 1918-00-9)||0.068b||Holt et al. (2010)|
(RS)-(ethyl 4-methylthio-m-tolyl isopropylphosphoramidate) (CAS 22224-92-6)
|0.058b||Holt et al. (2010)|
aMean of two lower bound values.
bLower bound values.
cng TEQ/g of ready-for-use product (active ingredient plus adjuvants).
dMean of four lower bound values.
|Precious metals recovery from wastes of jewelry factories and workshops||Incineration with ash recovery is said to be the only viable alternative for recovering precious metals from wastes from jewelry factories and workshops. PCDD/PCDF concentrations in air emissions of various combustion systems were as follows: 0.28 ng TEQ/m³ for a rotary furnace, afterburner and sleeve filters; 0.41 ng TEQ/m³ for a static furnace, afterburner and sleeve filters; 21 ng TEQ/m³ for a static furnace, afterburner without carbon system; 0.55 ng TEQ/m³ for combustion chamber, afterburner and sleeve filters; 0.026 ng TEQ/m³ combustion chamber, afterburner, sleeve filters, and lime + carbon abatement process (Baldassini et al. 2009).|
|Heat treatment of food salt||PCDD/PCDF have been detected at considerably higher levels in processed food salt than in natural salt. Comparing bamboo-salt and parched salt, Yang et al. (2004) found PCDD/PCDF levels were generally very low, with bamboo-salt having highest levels – from 5.7 x 10-5–0.64 pg TEQ/g. However, another study found considerably higher levels, with baked salts having a range of 1.33 - 16.92 pg TEQ/g and bamboo-salt, a range of 0.71-23.5 pg TEQ/g (Kim et al. 2002).|
Inventories: Searches of existing inventories will determine whether other Parties have identified the processes/activities of interest as PCDD/PCDF sources
National Chemicals Lists: Some countries have established lists of chemicals that must be tested for PCDD/PCDF before being placed on the market. Such lists include many chemicals that were or are suspected of containing PCDD/PCDF concentrations above certain limits. The processes for producing these chemicals are potential PCDD/PCDF sources.
Scientific Literature, Government Reports, etc.: Scientific journals, government reports, and related resources can be searched to determine whether
- the processes/activities of interest have been identified as PCDD/PCDF sources;
- the products, air emissions, wastewater effluents, or other residues of the processes/activities of interest have been found to contain PCDD/PCDF; or
- the products, air emissions, wastewater effluents or other residues of the processes/activities of interest have been identified as contributing to PCDD/PCDF at “hot spots” – contaminated production sites landfills, dumps, marine and freshwater sediments, soils, etc.
- the products, air emissions, wastewater effluents or other residues of the processes/activities of interest have been identified as contributing to PCDD/PCDF in surrounding air, soil, vegetation, and/or water; among workers or nearby residents; or among domestic and wild animals, fish, etc.
The tables above include examples of commercial chemicals, pesticides and processes/activities for which recent studies have found PCDD/PCDF in the products themselves and/or in associated wastes. The presence of PCDD/PCDF in these chemicals and pesticides is evidence of the need for more thorough assessments of the concentrations and frequency of occurrence of PCDD/PCDF in these substances, their production processes and associated emissions, discharges and residues as well as careful evaluation of their management and fate. Similarly, the presence of PCDD/PCDF in one or more wastes attests to the need to assay the PCDD/PCDF content of associated products and to evaluate carefully the management and fate of other process wastes as well as the use of the products.