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SOURCES OF DIOXINS

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FAIRY-TALE

Zero means zero. Dioxin releases must be eliminated, not reduced... ...Thus, zero is the only acceptable discharge of dioxin...

Greenpeace report 'Achieving Zero Dioxin' - July 1994 [1].

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FACTS AND FIGURES

Statement

There has never been zero dioxin discharge and there will never be. If you really mean zero, you have to stop all processes, whether they use chlorine or not, stop all combustion and heating and stop all traffic, including the Greenpeace ships...

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Sources of dioxins in The Netherlands

In The Netherlands, an inventory of almost all possible dioxin sources was made in 1991, by TNO, the scientific research institute of The Netherlands, for the Dutch Government. They did make a lot of measurements. All waste incinerators were measured, the whole chlorine industry was measured and some other possible sources were partly measured, from which estimates were made for the total amount released to air.
They also give figures for the expected emissions in the year 2000, after a lot of investments will be done to reduce the dioxin output of all sources. The results:

Measured and estimated emissions for 1991 to air and expected for 2000 after investments will be done to reduce the emissions:
All figures expressed in gram I-TEQ per year
 

Dioxin emissions in The Netherlands
Process 1991 2000
Incineration of municipal waste: 382.0 3.0
Sintering processes: 26.0 3.0
Use of PCP in the past: 25.0 20.0
Incineration of chemical waste: 16.0 1.7
Incineration of wood: 12.0 9.0
Traffic: 7.0 2.6
Metal industry: 4.0 4.0
Burning coal and brown-coal: 3.7 3.7
High temperature processes (e.g. glass): 2.7 2.7
Incineration of hospital waste: 2.1 0.0
burn-off of cables and motors: 1.5 1.5
Burning waste oil: 1.0 1.0
Chemical production processes 
including chlorine- and PVC-industry:		 0.5 0.5
Incineration of bio-gas and sludge: 0.3 1.5
Asphalt mixing: 0.3 0.3
Crematoria: 0.2 0.2
Total: 484.0 54.7
Source: RIVM/TNO inventory of dioxin sources in The Netherlands 1991 [3].

As you can see, the whole chlorine industry today counts for less than one thousandth of the total dioxin release in The Netherlands.
Only the - now forbidden - use of pentachlorophenol for wood treatment, which was years ago contaminated with dioxins, will give emissions even for many years in the future.

Sources of dioxins in Flanders

In Flanders (the North of Belgium), there was an inventory:

Measured and estimated for 1995/1997 to air:
All figures expressed in gram I-TEQ per year
 

Dioxin emissions in Flanders (air)
Process 1995 1997 variation
E-fact extent
Incineration of municipal waste: 187    9.2 0 0
Heating of buildings (mainly from wood): 122  53 2-3 0
Non-Ferro metals: 107   67.3 2 1
Incineration of hospital waste:  95    0.48 1 1
Sinter processes:  53.2 118 [*] 2 0
Lime kilns:  33.4   2 0
Incineration of industrial waste  20.9   17.5 1 1
Cement kilns:  20.8   2 0
Industrial heating:   7.00    3.4 2 0
Electro-steel:   6.42   2-3 0
Incidental fires:   2.56   2 2
Coke factories:   2.31   1 0
Car traffic:   1.71    1.1 1 0
Electricity:   1.07    1.47 2 0
Incineration of sludge:   0.75    2.35 1 1
Crematoria:   0.19    0.12 1 0
Chlorine- and VCM-production:   0.05    0.025 1 0
Incineration of bio-gas:   0.012   2 1
Paper bleaching:   0   2 1
Total: 662 274    
Sources: VITO, Materiaal dossier dioxines, 1995 [4].
Mira-T, 1999 [59].
E-fact: this is the variation in decades of the available measurements in similar processes
extent: 0 = more or less precisely known from measurements
  1 = not completely known, completed with estimates
  2 = no precise data, estimated
[*] This includes the whole iron/steel sector.

They made also a survey of dioxin sources to water:

Measured and estimated for 1995 to water:
All figures expressed in gram I-TEQ per year
 

Dioxin emissions in Flanders (water)
Process 1995 variation
E-fact extent
Sinter processes: 3.19 2 0
Cokes factories: 0.23 2 0
Chlorine- and VCM-production: 0.222 1 1
Crematoria: 0.19 1 0
Incineration of garbage: 0.0575 1 1
Incineration of industrial waste 0.021 1 1
Incidental fires: 0.015 2 2
Paper bleaching: 0 1 0
Total: 3.77    

The total amount of dioxins, measured in solid waste, was 485 g I-TEQ per year, more than 97% coming from municipal waste incineration.

Sources of dioxin in the UK

In the United Kingdom, an inventory was published:

Measured and estimated in 1995 to air:
All figures expressed in gram I-TEQ per year
 

Dioxin emissions in the UK
Process 1995 future
max		 quality
min max
MSW combustion: 460  580  15 H/M
Clinical waste combustion:  18   88   5 H/M
Industrial coal combustion:   5   67  67 H/M
Sinter plants:  29   54  47 M/L
Traffic:   1   45  45 H/L
Iron and steel:   3   41  14 M/L
Non-ferrous metals:   5   35  10 M/L
Crematoria:   1   35  35 H/L
Domestic coal combustion:  20   34  34 L/L
Domestic wood combustion:   2   18  18 L/L
Natural fires:   0.4   12  12 L/L
Cement manufacturing:   0.2   11  11 H/M
Straw combustion:   3.4   10  10 L/L
Chemical waste combustion:   1.5    8.7   0.3 M/M
Sewage sludge combustion:   0.7    6   0.9 H/H
Landfill gas combustion:   1.6    5.5   5.5 M/L
Industrial wood combustion:   1.4    2.9   2.9 M/L
Waste oil combustion:   0.8    2.4   2.4 M/L
Lime manufacture:   0.04    2.2   2.2 H/M
Coke production:      2   2 H/M
Tyres combustion:      1.7   1.7 H/H
Asphalt mixing:   0.047    1.6   1.6 H/M
PCP in timber processes:      0.8   0.8 L/L
Pesticide production:   0.1    0.3   0.3 L/M
Ceramic production:   0.02    0.06   0.06 H/M
Halogenated chemicals:      0.02   0.02 L/M
Glass manufacturing:   0.005    0.01   0.01 H/M
Carbon regeneration:      0.006   0.006 H/M
Total: 560 1100 350 g I-TEQ/year
Source: PCDD/F emissions to atmosphere in the UK and future trends. [10]
Quality: The values are assigned a rating for estimate quality. The first letter for quality of data relates to UK production and the second to the emissions data:
H = High, M = Medium and L = Low.

Sources of dioxin in the USA

In the USA there was a rough 1994 estimate of dioxin sources, which was updated with more accurate estimates at the beginning of 1998:

Average estimates of the 1998 USEPA dioxin inventory to air:
All figures expressed in gram I-TEQ per year.
 

Sources of dioxins to air in the US 
Process dioxin
Municipal waste incineration 1100
Backyard trash burning [*] 1125
Inadvertent landfill fires [**] 1050
Hospital waste incineration 461
Metal smelting 293
Forest, brush & straw fires 208
Wood, coal, vehicles 198
Cement kilns 171
Iron ore sintering 25
Sewage sludge incineration
15
Vinyl manufacturing 11
Source: USEPA draft dioxin inventory 2000 [53]
[*] Backyard trash burning evaluation, USEPA, November 1997 [54]. See next item
Order-of-magnitude estimate.
[**] Comment of the peer review panel for the dioxin inventory.
Order-of-magnitude estimate.

Most of the dioxin leaving the stacks, waste water treatment, via sludge disposal and PVC resin from the EDC/VCM/PVC manufacturing in the US were measured. The emissions to different environmental compartments can be compared with the USEPA estimates:

Average dioxin emissions from PVC manufacturing to different environmental compartments compared to total estimates:
All figures expressed in gram I-TEQ per year.
 

PVC manufacturing vs. total dioxin emissions 
Compartment PVC [*] Total Sources [**]
Air 11.3 2,745
Water 0.6 20
Land 0.7 208
Products 3.1 25,050
Total 15.7 28,023
[*] Vinyl Institute investigation of dioxin emissions from EDC/VCM/PVC manufacturing [55].
[**] USEPA draft dioxin inventory 1998 [53]

The high amounts of dioxin in "products" is mainly from the treatment of wood and other natural biodegradable products, to prevent biodegradation during their usefull life...

Greenpeace has supplied their own "estimates" of dioxin emissions from the PVC industry to the USEPA. These were based on dioxin content of "stolen" wastes of the production that are not leaving the factories at all, but in general are burned on site. The emissions of the incinerators that burn that kind of waste are included in the above figures...

Backyard barrelburning of household waste in the US

The USEPA has done some testing on the practice of backyard trash burning, which is still quite common in rural communities. For that purpose they used two scenario's, one of the non-recycler, burning everything that comes out the household bin, the other of the avid recycler, who takes out a lot of recyclable material. The non-recycler generates an average 4.9 kg of trash per household per day, while the avid recycler has only 1.5 kg/day. The average composition of both scenario's, based on realistic estimates, is quite different, so are the results. Tests 1 and 2 are with trash of the avid recycler, tests 4 and 5 for the non-recycler, test 3 was a blank test.

Measured emissions from backyard barrel burning:
Figures expressed in adjacent units
 

Results from the barrel burning tests
Type of waste Avid Recycler Non-recycler Units
Test number 1 2 4 5
Max. temp. base of barrel  440 300 740 640 °C
Max. temp. above barrel 280 500 300 650 °C
PVC in feed 4.5 4.5 0.2 0.2 %
Targeted volatile organic compounds 2916 1189 6147 2408 mg/kg
Tentatively identified VOC's 5373 2636 17517 11262 mg/kg
of which benzene 1068 378 1765 708 mg/kg
Chlorinated benzenes 287 1728 416 423 mg/kg
Polycyclic aromatic hydrocarbons 23.51 24.44 82.36 49.71 mg/kg
of which benzo(a)pyrene 1.12 0.23 3.12 1.12 mg/kg
Aldehydes and ketones 218 69 3958 1629 mg/kg
Sum PCDD/F on particulate and in vapor 0.493 0.0462 0.0523 0.0363 mg/kg
of wich sum 2,3,7,8 congeners 0.113 0.006 0.046 0.035 mg/kg
EPA-TEQ PCDD/F 2.769 0.172 0.157 0.067 µg/kg
Sum PCB's in vapor 1.01 0.93 3.08 2.63 mg/kg
PM10 7.46 4.18 21.28 16.23 g/kg
of which PM2.5 6.93 3.58 20.07 14.8 g/kg
Estimated copper emission in particulate 15.02 6.18 2.16 0.57 mg/kg
HCl in vapor 3.28 1.51 0.48 0.09 g/kg
Source: Backyard trash burning evaluation, USEPA, November 1997 [54].

Comment:
Dioxin releases from backyard trash burning, according to the USEPA researchers, can be influenced by the amount of PVC in the trash, the burning temperature and trace elements like copper. From the literature, we know that the chlorine/PVC content in the feed has little influence, while temperature, metals like copper and amount of particulate have a very large influence (see chemistry of dioxin formation).
This is also the case here: Although PVC is twenty times higher in the waste of the avid recycler (I wonder why, PVC can be recycled just as well!), that gives not more dioxin in test 2, compared with 4 and 5. Even if the differing test 1 is included, PVC in the waste shows only a weak correlation (0.58) with sum dioxin and if only the toxic 2,3,7,8-congeners are counted, there is even a negative correlation (-0.52)! A much stronger correlation exists with the combination of copper content of particulate and the amount of particulate (0.95) and if this is combined with the amount of HCl in the vapours, it is a near fit (0.997).
But even if you don't take into account the other influences, you can see that there is no direct correlation between PVC in the input and dioxin formation: 22 times more PVC in the input only gives 6 times more (sum) dioxin.

Like in all incineration or fires, here too it can be seen that the PAH emissions are much more important than dioxin emissions. That is also the case for the toxicologic relevance: in all cases, the cancerogenity of the amounts of benzo-(a)-pyrene, compared to I-TEQ dioxins are 80-500 times higher, even when large amounts of PVC were burned.

More important is the fact that backyard trash burning of only one household equals or surpasses the pollution of a full scale Municipal Waste Combustor (MWC), burning the waste of 37,000 non-recycling or 121,000 recycling households... It seems that Greenpeace and other groups are wasting their time by pointing to MWC's as dioxin source. These can perform even better, but backyard burning should be forbidden (as is already the case in Flanders/Belgium). Or would acting against backyard burning cost them too much members?

Sources of dioxin in Canada

At the beginning of 1999, the Canadian EPA released an inventory of dioxin sources in Canada.

PCDD/PCDF atmospheric releases in Canada in 1999 [*]:
All figures expressed in gram I-TEQ per year.
 

Dioxin Atmospheric Releases in Canada
Sector 1990 1997 1999 [*]
Municipal Waste Incineration 204.0 152.0 82.2
Wood Combustion (residential) 35.7 35.7 35.7
Iron Manufacturing: Sintering Plants 42.9 42.9 23.5
Pulp & Paper: Boilers Burning Salt Laden Wood 10.5 10.5 10.5
Steel Man.: Electric Arc Furnaces 9.1 10.2 10.2
Fuel Combustion Diesel (Traffic) 8.7 8.7 8.7
Oil Combustion (residential) 7.0 7.0 7.0
Electric Power Generation 3.4 4.6 4.6
Wood waste combustion (saw mills ans P&P mills) 4.4 4.4 4.4
Cement Kilns 2.6 2.8 2.8
Hospital Incinerators 8.3 2.5 2.5
Chemical Production (air releases) 2.2 2.0 0.3
In-service Utility Poles 1.9 1.9 1.9
Wood Preserving Plants 1.8 1.8 1.8
Hazardous Waste Incinerators 2.1 1.3 0.8
Pulp & Paper: Kraft Liquour Boilers 0.7 0.7 0.7
Federal Incinerators 1.3 0.6 0.6
Steel Foundries EAF 0.4 0.5 0.5
Sewage Sludge Incinerators 0.3 0.3 0.3
Base Metals Smelting 0.1 0.1 0.1
Secondary Lead Smelters 0.1 0.1 0.1
Biomedical Waste Incineration 4.9 0.0 0.0
Petroleum refineries (to follow)       
Total 353 290 199
Source: Dioxins and Furans and Hexachlorobenzene,
Inventory of Releases
Environment Canada, January 1999 [57].
[*] 1999 = projections.

Micro-contaminants from sea-ships

An investigation on three cruising ships [5] did reveal dioxin releases, comparable with the dioxin releases of a modern PVC factory, producing hundred thousands of tons of PVC per year.

Measured at the exhaust of three cruising ships:
 

Type of ship INPUT EMISSIONS
motor
power		 fuel
type		 chlorine
in fuel		 HCB+PCB dioxin
I-TEQ		 PAH mononitro
PAH's
units kW   mg/kg ng/m3 ng/m3 µg/m3 µg/m3
Ferry: 4,895 fuel 11   40 0.15 78 5.9
Rhine barge: 772 gasoil n.d. 165 0.03 41 0.3
Container-ship: 19,750 fuel   1.2  60 0.10 21 2.2

n.d.= not detectable

PAH's are non-chlorinated polycyclic aromatic hydrocarbons, of which several members are very potent carcinogens. The nitrated variety has members which are the most potent carcinogenic and mutagenic class of chemicals found until now.

If we assume an average fuel use of 1 ton/kW.year for a normal commercially used vessel, then we can calculate following emissions per year:

Calculated yearly emissions of three cruising ships:
 

Ship HCB+PCB dioxin
I-TEQ		 PAH mononitro
PAH
units g mg kg kg
Ferry:  7.8 28 15.3 1.16
Rhine barge:  5.1  1  1.3 0.01
Container-ship: 47.4 79 16.6 1.71

Comment:
To make a comparison: the average dioxin release to make 500,000 tons of PVC at the factory were we are working, is 50 mg/year...

Dioxin from natural processes

Forest, bush and grassland fires are one possible source of dioxins in nature. Estimates are varying from a few grams a year to several kg. Indeed, dioxin is found in the bark of thousands of years old redwoods and in human bodies of 6,000 years old. If this is a big source of dioxins in nature is not clear. Also after a recent dioxin scare in chicken meat in the US, the origin of the dioxins was found in millions of years old clay layers, not influenced by any man-made source [18].
Also interesting are complete biological routes which makes dioxins. A lot of wood rotting fungi and about half of all mushrooms use chlorinating and oxidising compounds to break down lignin, the glue which makes part of the strength of all plants. They need that to reach the cellulose, which they use as their source of energy. These organisms are very effective in transforming inorganic chlorine from salt into all kinds of chlorinated organics, mainly methylchloride, but also chlorinated phenols or alike compounds.
The remainder of this normal biological recycling of wood, is an amount of chlorinated humic acids and chlorinated lignin in water, chlorinated humus and chlorinated phenols in soil, the latter about seven times higher than allowed by legislation in The Netherlands [8]! From chlorinated phenols to dioxins is only a small step, you only need hydrogen peroxide, which is produced by a lot of micro-organisms. This results in the fact that, except for 'hot spots', near old incinerators and other point sources from the past, the highest amount of dioxins in soil is found in woods, not in industrial or heavy traffic areas.
While a bad incinerator emits nearly as much dioxins as what was going into the incinerator (but concentrates that in the vicinity) and a good one reduces the amount with 99.9% or more, the biological destruction of municipal sludge and the biological composting of natural organic material triples the amount of dioxins! Most probably this is the result of the same biological mechanism, which oxidises everywhere present natural chlorophenols.

That the processes which produce chlorophenols and dioxins is recently proven. Researchers added radio-labeled salt to forest soils [62]. After one year, the chlorophenols and dioxins found it that soil contained 30% radio-labeled chlorine.

Dioxin found in soil at different places. All figures as ng I-TEQ/kg dry material.
 

Dioxin found in soil at different places:
Place average
Municipal biological sludge: 62
Soil in woods: 26
Soil in industrial areas: 17
Bio-compost: 14
Soil from roadsides:  8
Soil from fields:   3.5
Source: Dioxin - Neuere Erkenntnisse zur Toxikologie und Epidemiologie [9].

World wide dioxin emission inventory

The United Nations Environmental Program (UNEP) has made an inventory of official inventories of sources of dioxins/furans [60]. Although only from industrial countries, it gives a good impression of what world wide is known of emitted quantities. Also some trends can be seen: in most countries the amounts of dioxins are falling rapidely, mainly because of stringent rules for incinerator emissions. There still is a large gap between the known emissions and what can be estimated as total emissions, based on measured world wide deposits.
The total deposit of PCDD/PCDF to land was calculated to be 12,500±1,300 kg sum (not I-TEQ!) per year. No world wide data were available for deposits into the oceans, but limited data and non-detects in Antarctica points to remote area deposits which are approaching zero. The authors therefore add 610±1,500 kg sum TCDD/F for the deposition into oceans. That makes a total of 13,100±2,000 kg sum TCDD/F. Using a calculation factor of 60 for the conversion of sum PCDD/F to I-TEQ, the annual deposition therefore would be 220±30 kg I-TEQ/year.

A rough estimate of known sources in industrial countries, recalculated for global emissions comes to 3,000±600 kg sum TCDD/F or approximately 50±10 kg I-TEQ/year. That is less than one quarter of the estimated deposits... Our impression is that the emissions of biomass combustion, especially forest fires, are highly underestimated:
 

Global PCDD/F emissions, reference year 1990
Process Emission Factor
sum µg/kg		 Production
Mton/yr		 Total Emission
sum kg/yr		 Rem
Waste incineration 13 87 1,130  
Cement kilns (+hazwaste) 2.6 260 680  
Biomass combustion 0.04 8700 350  
Ferrous metal production 0.5 700 350  
Cement kilns (no hazwaste) 0.2 1600 320  
Medical waste incineration 22 4 84 [*]
Sec. copper smelting 39 2 78  
Leaded fuel combustion 2800 3800 11 [**]
Unleaded fuel combustion 320 3800 1 [**]
Total sum PCDD/F kg/yr     3000  
I-TEQ PCDD/F kg/yr     50  
Source: Dioxin and Furan Inventories, UNEP,
May 1999 [60].

[*] Emission factor and production data only for the USA
[**] Emission factor units = pg/kg, production units = km/yr

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THE ALTERNATIVES

All forms of incineration or heating, all processes using any form of fossil heating and any form of combustion in transport will give emissions of dioxins, independent of the amount of chlorine at the input. See Chlorine input and dioxin emissions. And nothing can be produced and/or recycled and/or incinerated without the release of dioxins. See dioxin releases of materials during their life cycle.
Except for releases from the past, chlorine industry and chlorine products are among the least sources of dioxins today.

CONCLUSION

There is no reason to treat the release of dioxins from chlorine processes different from chlorine-free. And there is no reason at all to accuse the chlorine industry of today to be the main origin of large quantities of dioxins in the environment.
It is for 0.1% true that the chlorine- and PVC-industry is a source of dioxins, but it is for 99.9% untrue. And it is green fundamentalism to ask for a complete end of chlorine- and PVC-industry to 'solve' the dioxin problem, while much larger dioxin sources like domestic wood combustion and the metal industry not at all or rarely are attacked.

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Created: March 22, 1996.
Last update: September 8, 2001.

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