UNITED NATIONS ENVIRONMENT PROGRAMME
INTERNATIONAL LABOUR ORGANISATION
WORLD HEALTH ORGANIZATION
INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
ENVIRONMENTAL HEALTH CRITERIA 181
CHLORINATED PARAFFINS
This report contains the collective views of an international group of
experts and does not necessarily represent the decisions or the stated
policy of the United Nations Environment Programme, the International
Labour Organisation, or the World Health Organization.
First draft prepared by Dr K. Kenne and Professor U.G. Ahlborg,
Institute of Environmental Medicine, Karolinska Institute, Stockholm,
Sweden
Published under the joint sponsorship of the United Nations
Environment Programme, the International Labour Organisation, and the
World Health Organization, and produced within the framework of the
Inter-Organization Programme for the sound Management of Chemicals.
World Health Organization
Geneva, 1996
The International Programme on Chemical Safety (IPCS) is a joint
venture of the United Nations Environment Programme (UNEP), the
International Labour Organisation (ILO), and the World Health
Organization (WHO). The main objective of the IPCS is to carry out and
disseminate evaluations of the effects of chemicals on human health
and the quality of the environment. Supporting activities include
the development of epidemiological, experimental laboratory, and
risk-assessment methods that could produce internationally comparable
results, and the development of manpower in the field of toxicology.
Other activities carried out by the IPCS include the development of
know-how for coping with chemical accidents, coordination of
laboratory testing and epidemiological studies, and promotion of
research on the mechanisms of the biological action of chemicals.
The Inter-Organization Programme for the Sound Management of
Chemicals (IOMC) was established in 1995 by UNEP, ILO, the Food and
Agriculture Organization of the United Nations, WHO, the United
Nations Industrial Development Organization and the Organisation for
Economic Co-operation and Development (Participating Organizations),
following recommendations made by the 1992 UN Conference on
Environment and Development to strengthen cooperation and increase
coordination in the field of chemical safety. The purpose of the IOMC
is to promote coordination of the policies and activities pursued by
the Participating Organizations, jointly or separately, to achieve the
sound management of chemicals in relation to human health and the
environment.
WHO Library Cataloguing in Publication Data
Chlorinated paraffins.
(Environmental health criteria ; 181)
1.Paraffin - adverse effects 2.Paraffin - toxicity
3.Environmental exposure I.Series
ISBN 92 4 157181 0 (NLM Classification: QV 800)
ISSN 0250-863X
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CONTENTS
ENVIRONMENTAL HEALTH CRITERIA FOR CHLORINATED PARAFFINS
Preamble
1. SUMMARY
1.1. Properties, uses and analytical methods
1.2. Sources of human and environmental exposure
1.3. Environmental distribution and transformation
1.4. Environmental levels and human exposure
1.5. Kinetics and metabolism
1.6. Effects on laboratory mammals and in vitro
test systems
1.7. Effects on humans
1.8. Effects on other organisms in the laboratory
and field
1.9. Evaluation of human health risks and effects on the
environment
2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, AND ANALYTICAL
METHODS
2.1. Identity
2.1.1. Relative molecular mass
2.1.2. Common names
2.1.2.1 CAS registry number and names
2.1.2.2 Synonyms
2.1.3. Technical products
2.2. Chemical and physical properties
2.3. Analysis
2.3.1. Sampling
2.3.2. Analytical methods
3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses
3.2.3. Loss into the environment
4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION AND TRANSFORMATION
4.1. Transport and distribution between media
4.2. Transformation
4.2.1. Abiotic transformation
4.2.2. Biodegradation
4.2.2.1 Short chain length chlorinated
paraffins
4.2.2.2 Long chain length chlorinated
paraffins
4.2.2.3 Comparative studies
4.3. Bioaccumulation and biomagnification
4.3.1. Summary
4.3.2. Aquatic vertebrates
4.3.2.1 Short chain length chlorinated
paraffins
4.3.2.2 Intermediate chain length chlorinated
paraffins
4.3.2.3 Long chain length chlorinated
paraffins
4.3.3. Aquatic invertebrates
4.3.3.1 Short chain length chlorinated
paraffins
4.3.3.2 Intermediate chain length chlorinated
paraffins
4.3.3.3 Long chain length chlorinated
paraffins
4.3.3.4 Comparative studies
4.3.4. Aquatic plants
5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Air
5.1.2. Water and sediment
5.1.3. Soil
5.1.4. Aquatic and terrestrial organisms
5.1.5. Food and beverages
5.2. General population exposure
5.2.1. Concentrations in human tissues
5.3. Occupational exposure
6. KINETICS AND METABOLISM IN LABORATORY ANIMALS
6.1. Absorption
6.1.1. Oral exposure
6.1.2. Dermal exposure
6.1.3. Inhalation exposure
6.2. Distribution
6.2.1. Short chain length chlorinated paraffins
6.2.1.1 Mouse
6.2.1.2 Rat
6.2.2. Intermediate chain length chlorinated paraffins
6.2.2.1 Rat
6.2.2.2 Mouse
6.2.2.3 Bird
6.2.2.4 Fish
6.2.3. Long chain length chlorinated paraffins
6.2.3.1 Rat
6.2.3.2 Fish
6.2.3.3 Mussel
6.2.4. Comparative studies
6.3. Metabolic transformation
6.3.1. Short chain length chlorinated paraffins
6.3.2. Intermediate chain length chlorinated paraffins
6.4. Elimination and excretion
6.4.1. Short chain length chlorinated paraffins
6.4.2. Intermediate chain length chlorinated paraffins
6.4.2.1 Rat
6.4.2.2 Mouse
6.4.2.3 Bird
6.4.3. Long chain length chlorinated paraffins
6.4.4. Comparative studies
7. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
7.1. Acute exposure
7.1.1. Lethal doses
7.1.2. Non-lethal doses
7.1.2.1 Oral route
7.1.2.2 Inhalation route
7.1.2.3 Intraperitoneal route
7.1.3. Skin and eye irritation
7.1.3.1 Short chain length chlorinated
paraffins
7.1.3.2 Intermediate and long chain length
chlorinated paraffins
7.1.4. Skin sensitization
7.2. Repeated exposure
7.2.1. Oral route
7.2.1.1 Short chain length chlorinated
paraffins
7.2.1.2 Intermediate chain length chlorinated
paraffins
7.2.1.3 Long chain length chlorinated
paraffins
7.2.1.4 Comparative studies
7.2.2. Intraperitoneal route
7.2.2.1 Short chain length chlorinated
paraffins
7.2.2.2 Intermediate chain length chlorinated
paraffins
7.2.2.3 Comparative studies
7.3. Neurotoxicity
7.3.1. Short chain length chlorinated paraffins
7.3.2. Intermediate chain length chlorinated paraffins
7.4. Reproductive toxicity, embryotoxicity and
teratogenicity
7.4.1. Reproduction
7.4.2. Embryotoxicity and teratogenicity
7.4.2.1 Short chain length chlorinated
paraffins
7.4.2.2 Intermediate chain length chlorinated
paraffins
7.4.2.3 Long chain length chlorinated
paraffins
7.5. Mutagenicity and related end-points
7.5.1. Prokaryotes
7.5.2. Mammalian cells
7.5.2.1 In vitro studies
7.5.2.2 In vivo studies
7.5.2.3 Cell transformation
7.6. Long-term exposure and carcinogenicity
7.6.1. Oral route
7.6.1.1 Short chain length chlorinated
paraffins
7.6.1.2 Long chain length chlorinated
paraffins
8. EFFECTS ON HUMANS
8.1. General population exposure
8.1.1. Controlled human studies
8.2. Occupational exposure
9. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD
9.1. Laboratory experiments
9.1.1. Microorganisms
9.1.2. Aquatic organisms
9.1.2.1 Aquatic plants
9.1.2.2 Invertebrates
9.1.2.3 Fish
9.1.3. Terrestrial organisms
9.2. Field observations
10. EVALUATION OF HUMAN HEALTH RISKS AND EFFECTS ON THE ENVIRONMENT
10.1. Evaluation of human health risks
10.1.1. Exposure levels
10.1.2. Toxic effects
10.1.3. Risk evaluation
10.1.3.1 Short chain compounds
10.1.3.2 Intermediate chain compounds
10.1.3.3 Long chain compounds
10.2. Evaluation of effects on the environment
10.2.1. Exposure levels
10.2.2. Toxic effects
10.2.3. Risk evaluation
11. RECOMMENDATIONS FOR PROTECTION OF THE ENVIRONMENT
12. FUTURE RESEARCH
13. PREVIOUS EVALUATION BY INTERNATIONAL ORGANIZATIONS
REFERENCES
RESUME
RESUMEN
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WHO TASK GROUP ON ENVIRONMENTAL HEALTH CRITERIA FOR CHLORINATED
PARAFFINS
Members
Professor U.G. Ahlborg, Institute of Environmental Medicine,
Karolinska Institute, Stockholm, Sweden (Vice-Chairman)
Dr D. Anderson, British Industry Biological Research Association
(BIBRA) Toxicology International, Carshalton, Surrey, United
Kingdom
Dr T. Beulshausen, Federal Environment Agency, Berlin, Germany
Dr R.S. Chhabra, Environmental Toxicology Program, National Institute
of Environmental Health Sciences, Research Triangle Park, North
Carolina, USA
Dr N. Gregg, Health and Safety Executive, Bootle, Merseyside, United
Kingdom
Mr P.D. Howe, Institute of Terrestrial Ecology, Monks Wood,
Huntingdon, Cambridgeshire, United Kingdom (Joint Rapporteur)
Dr B. Jansson, Institute of Applied Environmental Research, Stockholm
University, Solna, Sweden
Dr K. Kenne, Institute of Environmental Medicine, Karolinska
Institute, Stockholm, Sweden (Joint Rapporteur)
Dr M.E. Meek, Environmental Health Directorate, Health Canada, Ottawa,
Ontario, Canada (Chairman)
Representatives of other Organizations
Dr P. Montuschi, Institute of Pharmacology, Faculty of Medicine and
Surgery, Catholic University of the Sacred Heart, Rome, Italy
(Representing the International Union of Pharmacology)
Mr D. Farrar, Occupational Health, ICI Chemicals and Polymers Limited,
Runcorn, Cheshire, United Kingdom
(Representing the European Centre for Ecotoxicology and Toxicology
of Chemicals)
Secretariat
Dr E.M. Smith, International Programme on Chemical Safety, World
Health Organization, Geneva, Switzerland (Secretary)
Mr J.D. Wilbourn, Unit of Carcinogen Identification and Evaluation,
International Agency for Research on Cancer, Lyon, France
ENVIRONMENTAL HEALTH CRITERIA FOR CHLORINATED PARAFFINS
A WHO Task Group on Environmental Health Criteria for Chlorinated
Paraffins met at the World Health Organization, Geneva, from 20 to 24
March 1995. Dr E.M. Smith, IPCS, welcomed the participants on behalf
of Dr M. Mercier, Director of the IPCS, and on behalf the three IPCS
cooperating organizations (UNEP/ILO/WHO). The Group reviewed and
revised the draft and made an evaluation of the risks for human health
and the environment from exposure to chlorinated paraffins.
The first draft was prepared at the Institute of Environmental
Medicine, Karolinska Institute, Stockholm, Sweden, by Dr K. Kenne and
Professor U.G. Ahlborg. The second draft, incorporating comments
received following circulation of the first drafts to the IPCS contact
points for Environmental Health Criteria monographs, was also prepared
by Dr Kenne and Professor Ahlborg.
Dr E.M. Smith and Dr P. Jenkins, both of the IPCS Central Unit,
were responsible for the scientific aspects of the monograph and for
the technical editing, respectively.
The efforts of all who helped in the preparation and finalization
of the monograph are gratefully acknowledged.
ABBREVIATIONS
APDM aminopyrine demethylase
BCF bioconcentration factor
CD coulometric detection
CP chlorinated paraffins
CP-LH chlorinated paraffin with long chain length and high degree
of chlorination
CP-LL chlorinated paraffin with long chain length and low degree of
chlorination
CP-MH chlorinated paraffin with medium chain length and high degree
of chlorination
CP-ML chlorinated paraffin with medium chain length and low degree
of chlorination
CP-SH chlorinated paraffin with short chain length and high degree
of chlorination
CP-SL chlorinated paraffin with short chain length and low degree
of chlorination
EC50 median effective concentration
ECD electron capture detection
GC gas chromatography
LC50 median lethal concentration
LOAEL lowest-observed-adverse-effect level
LOEC lowest-observed-effect concentration
LOEL lowest-observed-effect level
LT50 median lethal time
MS mass spectrometry
NCI negative ion chemical ionization
NOAEL no-observed-adverse-effect level
NOEL no-observed-effect level
PCB polychlorinated biphenyl
PVC polyvinyl chloride
TDI tolerable daily intake
TLC thin-layer chromatography
TSH thyroid stimulating hormone
UDP uridine diphosphate
1. SUMMARY
1.1 Properties, uses and analytical methods
Chlorinated paraffins (CPs) are produced by chlorination of
straight-chained paraffin fractions. The carbon chain length of
commercial chlorinated paraffins is usually between 10 and 30 carbon
atoms, and the chlorine content is usually between 40 and 70% by
weight. Chlorinated paraffins are viscous colourless or yellowish
dense oils with low vapour pressures, except for those of long carbon
chain length with high chlorine content (70%), which are solid.
Chlorinated paraffins are practically insoluble in water, lower
alcohols, glycerol and glycols, but are soluble in chlorinated
solvents, aromatic hydrocarbons, ketones, esters, ethers, mineral oils
and some cutting oils. They are moderately soluble in unchlorinated
aliphatic hydrocarbons.
Chlorinated paraffins consist of extremely complex mixtures,
owing to the many possible positions for the chlorine atoms. The
products can be subdivided into six groups depending on chain length
(short C10-13, intermediate C14-17 and long C18-30) and degree of
chlorination (low (< 50%) and high (> 50%)).
Chlorinated paraffins are used worldwide in widespread
applications such as plasticizers in plastics (e.g., PVC), extreme
pressure additives in metal working fluids, flame retardants and
additives in paints. Technical grade chlorinated paraffins may be
contaminated by isoparaffins, aromatic compounds and metals, and
normally contain stabilizers, which are added to inhibit
decomposition.
The analysis of chlorinated paraffins is difficult due to the
extreme complexity of these mixtures. In environmental samples, this
is further complicated by interference from other compounds. Analyses
often require extensive clean-up of the samples and the use of
specific detection methods. Early methods were based on thin-layer
chromatography for the clean-up and an unspecific argentation
detection method on the plates. Methods based on different column
liquid chromatography are currently used for the clean-up, although it
is difficult to isolate the chlorinated paraffins due to their wide
range of physical properties. Specific detection methods are
therefore used; gas chromatography combined with mass spectrometry is
now the most common technique. The use of negative ions makes the
detection even more specific. Although use of these sophisticated
techniques has improved the ability to analyse chlorinated paraffins,
it is still impossible to determine exact concentrations. Reported
results should be regarded only as estimates of the true values.
1.2 Sources of human and environmental exposure
Chlorinated paraffins are not known to occur naturally.
Chlorinated paraffins are produced by reacting liquid paraffin
fractions with pure chlorine gas. The reaction may require the use of
a solvent, and often ultraviolet light is used as a catalyst. In
1985, the estimated world production of chlorinated paraffins was
300 000 tonnes.
The widespread uses of chlorinated paraffins probably provide the
major source of environmental contamination. Chlorinated paraffins
may be released into the environment from improperly disposed
metal-working fluids containing chlorinated paraffins or from polymers
containing chlorinated paraffins. Loss of chlorinated paraffins by
leaching from paints and coatings may also contribute to environmental
contamination. The potential for loss during production and transport
is expected to be less than that during product use and disposal.
Owing to their thermal instability, chlorinated paraffins are
expected to be degraded by incineration and thus would not be expected
to volatilize in exhaust gases from incinerators. However, it has
been demonstrated that chlorinated aromatic compounds such as
polychlorinated biphenyls, naphthalenes and benzenes are formed by
pyrolysis of chlorinated paraffins under certain conditions.
1.3 Environmental distribution and transformation
Chlorinated paraffins adsorb strongly to sediment. In water they
are probably transported adsorbed on suspended particles, and in the
atmosphere adsorbed to airborne particulates (and possibly in the
vapour phase). The half-lives for chlorinated paraffins in air have
been estimated to range from 0.85 to 7.2 days, a period sufficiently
long that the possibility of long-range transport cannot be excluded.
Chlorinated paraffins are not readily biodegradable. Short
carbon chain length chlorinated paraffins with a chlorine content of
less than 50% appear to be degradable under aerobic conditions with
acclimated microorganisms, whereas the degradation appears inhibited
at a chlorine content above 58%. Intermediate and long chain length
chlorinated paraffins are degraded more slowly.
Chlorinated paraffins are bioaccumulated in aquatic organisms,
and the reported bioconcentration factors (BCFs) are in the range of 7
to 7155 for fish and 223 to 138 000 for mussels. In fish, chlorinated
paraffins of short chain length are accumulated to a higher degree
than intermediate and long chain length chlorinated paraffins.
Radioactivity has been found mainly in bile, intestine, liver, fat and
gills after administration of radiolabelled chlorinated paraffins. The
uptake of chlorinated paraffins seems to be more efficient for short
chlorinated paraffins with low chlorine content; the elimination rate
is slowest for short chlorinated paraffins with high chlorine content.
The retention in fat-rich tissues appears to increase with increasing
degree of chlorination.
1.4 Environmental levels and human exposure
Few data on levels of chlorinated paraffins in the environment
are available. Chlorinated paraffins have been detected in marine
water samples in the United Kingdom at levels below 4 µg/litre. In
non-marine waters, levels below 6 µg/litre in the United Kingdom have
been reported; in Germany, concentrations determined in 1994 were in
the range of 0.08-0.28 µg/litre. In water in the USA, concentrations
were generally less than 0.03 µg/litre, although levels were above 1.0
µg/litre in a small proportion (1.2%) of samples. In marine sediments,
levels up to 600 µg/kg wet weight have been reported, and in
non-marine sediments in the United Kingdom concentrations were up to
15 000 µg/kg in industrialized regions and 1000 µg/kg in areas
remote from industry. In sediments in an impoundment lagoon from a
chlorinated paraffin manufacturing plant in the USA, concentrations as
high as 170 000 µg/kg dry weight of long chain length chlorinated
paraffins, 50 000 µg/kg of intermediate chain length chlorinated
paraffins and 40 000 µg/kg of short chain length chlorinated paraffins
were reported. In Germany, levels up to 83 µg/kg dry weight of C10-13
and up to 370 µg/kg dry weight of C14-17 were reported in sediments in
1994. In Japan, levels in sediment ranged up to 8500 µg/kg.
Chlorinated paraffins have been detected in various organisms.
Chlorinated paraffins are present in terrestrial mammals in Sweden at
concentrations in the range of 32-88 µg/kg tissue (140-4400 µg/kg
lipid). However, chlorinated paraffins were not detected in sheep
which were grazed remote from production of chlorinated paraffins in
the United Kingdom. In birds in the United Kingdom, concentrations
ranged up to 1500 µg/kg and in fish in Sweden and the United Kingdom,
levels ranged up to 200 µg/kg. In mussels collected in the USA and
United Kingdom, concentrations up to 400 µg/kg were reported.
However, levels of C10-20 in mussels collected close to a chlorinated
paraffin plant effluent discharge ranged up to 12 000 µg/kg.
Chlorinated paraffins have also been detected in post mortem human
tissues, i.e. in adipose tissue (median level of 100-190 µg/kg),
kidney (median level below 90 µg/kg) and liver (median level below 90
µg/kg). In one limited survey, chlorinated paraffins, mostly C10-20,
were present at levels of up to 500 µg/kg in approximately 70% of the
samples of various food products.
Information on occupational exposure to chlorinated paraffins is
limited. Very low levels of exposure to aerosols of short chain
chlorinated paraffins (0.003-1.2 mg/m3) have been found to be
associated with their use as metal-working fluids, although there is
no information available on the proportion that is inhalable. On the
basis of mathematical modelling of exposure without any control
measures, high levels of dermal contact (5-15 mg/cm2 per day) were
estimated for speciality metal-working fluids which contain very high
levels of short chain chlorinated paraffins, although absorption would
be expected to be low. Control measures would reduce dermal exposure.
1.5 Kinetics and metabolism
The toxicokinetics of chlorinated paraffins have been studied
in experimental animals. Adequate information for humans is not
available. Possible differences in toxicokinetics as a result of
different chain lengths have not been sufficiently investigated.
Although the extent of absorption of chlorinated paraffins after oral
administration is unknown, it appears to decrease with increasing
chain length and degree of chlorination. Percutaneous absorption may
also occur depending on chain length, but would be limited (less than
1% of a topical C18 dose). No data on absorption via the lung is
available.
Distribution of chlorinated paraffins occurs mainly in the liver,
kidney, intestine, bone marrow, adipose tissue and ovary. Information
on retention is insufficient but a low degree of chlorination may
enhance retention time due to slower redistribution. Chlorinated
paraffins or their metabolites are present in the central nervous
system up to 30 days after administration. They may cross the
blood-placental barrier. There is no adequate information on the
pathways of metabolism of chlorinated paraffins, although in
radiolabelling studies CO2 has been identified as an end-product.
Chlorinated paraffins may be excreted via the renal, biliary and
the pulmonary routes (as CO2). The relative extent of excretion
via the different routes is difficult to establish due to the
wide variability in different studies. The total elimination of
chlorinated paraffins decreases as the chlorine content increases, and
compounds with high degrees of chlorination are mainly excreted (more
than 50%) as CO2. Chlorinated paraffins may be excreted in milk.
1.6 Effects on laboratory mammals and in vitro test systems
The acute oral toxicity of chlorinated paraffins of various chain
lengths is low. Toxic effects such as muscular incoordination and
piloerection were most evident following single exposure to short
chain length chlorinated paraffins. On the basis of very limited
data, the acute toxicity by the inhalation and dermal routes also
appears to be low. Mild skin and eye irritation has been observed
after application of short and intermediate (skin irritation)
chain length chlorinated paraffins. Results of several studies
indicate that short chain chlorinated paraffins do not induce skin
sensitization.
In repeated dose toxicity studies by the oral route, the liver,
kidney and thyroid are the primary target organs for the toxicity of
the chlorinated paraffins. For the short chain compounds, increases
in liver weight have been observed at lowest doses (lowest-observed-
effect level is 50 to 100 mg/kg body weight per day and no-observed-
effect level is 10 mg/kg body weight per day in rats). At higher
doses, increases in the activity of hepatic enzymes, proliferation
of smooth endoplasmic reticulum and peroxisomes, replicative DNA
synthesis, hypertrophy, hyperplasia and necrosis of the liver have
also been observed. Decreases in body weight gain (125 mg/kg body
weight per day in mice), increases in kidney weight (100 mg/kg body
weight per day in rats), replicative DNA synthesis in renal cells
(313 mg/kg body weight per day) and nephrosis (625 mg/kg body weight
per day in rats) have also been observed. Increases in thyroid
weight, and hypertrophy and hyperplasia of the thyroid (LOEL of
100 mg/kg body weight per day in rats) and replicative DNA synthesis
in thyroid follicular cells (LOEL of 313 mg/kg body weight per day)
have been reported. At higher doses (1000 mg/kg body weight per day),
thyroid function is affected, as determined by free and total levels
of plasma thyroxine and increased plasma thyroid-stimulating hormone
in rats.
For the intermediate chain compounds, effects observed at lowest
doses are generally increases in liver and kidney weight (LOEL in rats
of 100 mg/kg body weight per day; NOAEL in rats of 10 mg/kg body
weight per day). Increases in serum cholesterol and "mild, adaptive"
histological changes in the thyroid have been reported at similar
doses in female rats (NOAEL of 4 mg/kg body weight per day).
For the long chain compounds, effects observed at lowest doses
are multifocal granulomatous hepatitis and increased liver weights in
female rats (LOAEL of 100 mg/kg body weight per day).
In the only identified reproduction study, no adverse
reproductive effects were reported following exposure of rats to an
intermediate chain length chlorinated paraffin with 52% chlorine.
However, survival and body weights of the exposed pups were reduced
(LOEL for non-significant decrease in body weight of 5.7-7.2 mg/kg
body weight per day; LOAEL for decreased survival of 60-70 mg/kg body
weight per day). In a limited number of studies of the developmental
effects of the short, medium and long chain chlorinated paraffins,
adverse effects in the offspring were observed for the short chain
compounds only, at maternally toxic doses in rats (2000 mg/kg body
weight per day). For the medium and long chain compounds, no effects
on the offspring were observed even at very high doses (1000 to
5000 mg/kg body weight per day).
Chlorinated paraffins do not appear to induce mutations in
bacteria. However, in mammalian cells, there is a suggestion of a
weak clastogenic potential in vitro but not in vivo. Chlorinated
paraffins are also reported to induce cell transformation in vitro.
Long term carcinogenicity studies by oral gavage in rats and mice
have been conducted on a short chain chlorinated paraffin (C12;
58% Cl) and a long chain chlorinated paraffin (C23; 43% Cl). For
the short chain compound in B6C3F1 mice, there were increases in
the incidence of hepatic tumours in males and females and tumours of
the thyroid gland in females. In Fischer-344 rats exposed to the short
chain compound, there were increases in hepatic tumours in males and
females, renal tumours (adenomas or adenocarcinomas) in males, tumours
of the thyroid in females and mononuclear cell leukaemias in males.
For the long chain chlorinated paraffin, the incidences of malignant
lymphomas in male mice and tumours of the adrenal gland in female rats
were increased.
1.7 Effects on humans
In spite of the widespread use of chlorinated paraffins, there
are no case reports of skin irritation or sensitization. This is
supported by results of a limited number of studies in volunteers in
which chlorinated paraffins have induced minimal irritancy in the
skin, but not sensitization.
Data on other effects of chlorinated paraffins in humans have not
been identified.
1.8 Effects on other organisms in the laboratory and field
Chlorinated paraffins of short chain length have been shown to
be acutely toxic to freshwater and saltwater invertebrates, with
LC50-EC50 values ranging from 14 to 530 µg/litre. Most of the acute
toxicity tests on aquatic invertebrates for intermediate and long
chain chlorinated paraffins exceed the water solubility. However, a
study on an intermediate chlorinated paraffin product shows acute
toxicity to daphnids at an EC50 of 37 µg/litre. Short, intermediate
and long chain chlorinated paraffins appear to be of low acute
toxicity to fish, with LC50 values well in excess of the water
solubility.
Short chain length chlorinated paraffins show long-term toxicity
to algae, aquatic invertebrates and fish at concentrations as low
as 19.6, 8.9 and 3.1 µg/litre, respectively; no-observed-effect
concentrations appear to be in the range of 2 to 5 µg/litre for the
most sensitive species tested. An intermediate and a long chain
product showed chronic effects on daphnids at concentrations of 20 to
35 µg/litre and < 1.2 to 8 µg/litre, respectively. Long-term
toxicity to fish seems to be low. No data are available on algae.
On the basis of limited available data, the acute toxicity of
chlorinated paraffins in birds is low.
1.9 Evaluation of human health risks and effects on the environment
It is likely that the principal source of exposure of the general
population is food. On the basis of limited data on concentrations
present in foodstuffs, worst case estimates of daily intake in dairy
products and mussels, respectively, are 4 and 25 µg/kg body weight
per day. In general, the calculated daily intakes of chlorinated
paraffins are below the tolerable intakes for non-neoplastic effects
or recommended values for neoplastic effects (short chain compounds).
Provided that proper personal hygiene and safety procedures are
followed, the risk to health for workers exposed to chlorinated
paraffins is expected to be minimal.
Available data indicate that chlorinated paraffins are
bioaccumulative and persistent. The data on environmental levels of
short chain chlorinated paraffins indicate that in areas close to
release sources there is a risk to both freshwater and estuarine
organisms. There is also a potential risk to aquatic invertebrates
from intermediate and long chain chlorinated paraffin products.
The enrichment of chlorinated paraffins in sediments, their
resorption behaviour and aquatic toxicity indicate a potential risk
for sediment-dwelling organisms.
2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, AND ANALYTICAL METHODS
2.1 Identity
Chlorinated paraffins (CPs) are produced by chlorination of
normal paraffin fractions (straight-chain hydrocarbons, at least 98%
linear), and have the general formula CxH(2x-y+2)Cly. The length of
the carbon chains is usually between 10 and 30 carbon atoms, and the
chlorine content is between 20 and 70% by weight, although the
commercial products normally fall within the 40-70% Cl range
(Schenker, 1979). In this monograph the different isomers will be
referred to as Cx;y% Cl, i.e., a chlorinated paraffin with a carbon
chain length of 12 and a chlorination degree of 60% will be referred
to as C12;60% Cl.
Commercial chlorinated paraffins, of which there are over 200,
are very complex mixtures of n-alkanes characterized by an average
carbon chain length and chlorination degree. Each grade varies in the
range of carbon chain length, but also in the distribution and degree
of chlorination. The different technical grades have therefore
specific physical and chemical properties which render them useful in
such widespread applications as plasticizers in plastics such as
polyvinyl chloride, extreme pressure additives, flame retardants and
paints.
The number of theoretically possible structures within the ranges
C10-C30 and 40-70% Cl is enormous. Taking C12 and 60% Cl as an
example, there are numerous possibilities, depending on the position
of the chlorine atoms. In just one of these structures (Fig. 1),
there are 25=32 different diastereomers, owing to the five optical
sites (indicated by an asterisk).
The raw materials most frequently used for the production of
chlorinated paraffins are normal paraffin feedstocks, which fall into
three main categories:
1) a liquid fraction including C10-C13 with an average of C12;
2) a liquid fraction including C14-C17 with an average of C15; and
3) a wax fraction including C20-C28 with an average of C24 (Strack,
1986).
A wax fraction including C18-C20 is also used. Depending on
the feedstock and the degree of chlorination, long chain length
chlorinated paraffins (C18-30) range from being mobile to very viscous
liquids, with the exception of the C20-30;70% Cl type, which is a
solid.
In general chlorinated paraffins are classified as short chain
(C10-13), intermediate chain (C14-17) and long chain (C18-30). These
groups are further divided into two classes according to chlorine
content: < 50% and > 50% chlorine. A suggested classification of
the different chlorinated paraffin isomers is shown in Table 1. The
suggested acronyms are used in this monograph.
2.1.1 Relative molecular mass
The relative molecular mass depends on the carbon chain length
and the degree of chlorination. The chlorinated paraffin C10;50.6%
Cl has a relative molecular mass of 280.1, whereas that of C25;69% Cl
is 1075.
2.1.2 Common names
2.1.2.1 CAS registry number and names
63449-39-8 Paraffin waxes and hydrocarbon waxes, chloro
85422-92-0 Paraffin oils and hydrocarbon oils, chloro
61788-76-9 Alkanes, chloro
68920-70-7 Alkanes, C6-18, chloro
71011-12-6 Alkanes, C12-13, chloro
84082-38-2 Alkanes, C10-21, chloro
84776-06-7 Alkanes, C10-32, chloro
84776-07-8 Alkanes, C16-27, chloro
85049-26-9 Alkanes, C16-35, chloro
85535-84-8 Alkanes, C10-13, chloro
85535-85-9 Alkanes, C14-17, chloro
85535-86-0 Alkanes, C18-28, chloro
85536-22-7 Alkanes, C12-14, chloro
85681-73-8 Alkanes, C10-14, chloro
97659-46-6 Alkanes, C10-26, chloro
97553-43-0 Paraffins (petroleum), normal C > 10, chloro
106232-85-3 Alkanes, C18-20, chloro
106232-86-4 Alkanes, C22-40, chloro
108171-26-2 Alkanes, C10-12, chloro
108171-27-3 Alkanes, C22-26, chloro
2.1.2.2 Synonyms
Alkanes, chlorinated; alkanes (C10-12), chloro (60%); alkanes (C10-13),
chloro (50-70%); alkanes (C14-17), chloro (40-52%); alkanes (C18-28),
chloro (20-50%); alkanes (C22-26), chloro (43%); C12, 60% chlorine;
C23, 43% chlorine; chlorinated alkanes; chlorinated hydrocarbon
waxes; chlorinated paraffin waxes; chlorinated waxes; chloroalkanes;
chlorocarbons; chloroparaffin waxes; paraffin, chlorinated; paraffins,
chloro; paraffin waxes, chlorinated; paroils, chlorinated; poly-
chlorinated alkanes; polychloro alkanes.
2.1.3 Technical products
Chlorinated paraffins are manufactured commercially by a number
of companies and are marketed under a variety of trade names. The
trade names are followed by numbers, which often are related to the
average chlorine content (in percent) of a particular preparation.
However, this is not a rule and the average chlorine content may have
to be obtained from manufacturers' technical data. More than 200
chlorinated paraffin formulations are commercially available
world-wide (Serrone et al., 1987), and some examples of these are
given in Table 2.
The carbon chain length of the chlorinated paraffins in a
commercial mixture is variable, and the average chain length is
usually specified by the manufacturer. The composition of paraffins
of different chain length in some commercial formulations is shown in
Table 3. The paraffin feedstocks are randomly chlorinated and the
resulting chlorine contents are given as average values.
Commercial chlorinated paraffins may be contaminated by
isoparaffins (usually less than 1%), aromatic compounds (usually less
than 0.1% (1000 ppm)) and metals (Schenker, 1979).
Chlorinated paraffins normally contain stabilizers, which are
added to inhibit decomposition. Common stabilizers include epoxidized
compounds such as epoxidized esters and soya bean oils (indicated in
section 7.1.3 to be present at up to 3%), pentaerythritol, thymol,
urea, glycidyl ethers, acetonitriles and organic phosphites (Schenker,
1979; Strack, 1986; Houghton, 1993). The concentration of stabilizers
is usually below 0.05% w/w (Campbell & McConnell, 1980).
Table 2. Partial list of commercial chlorinated paraffinsa
Average molecular formula C12H15Cl11 C12H19Cl7 C15H26Cl6 C24H29Cl21 C24H42Cl8 C24H44Cl6
Chlorine content (% w/w) 70 60-65 50-52 70 48-54 40-42
Manufacturers:
Oxychem, USA Chlorowax 70L Chlorowax 500C Chlorowax 70 Chlorowax 50 Chlorowax 40
Keil Chemical Div., USA CW-200-70 CW-85-60 CW-52 CW-220-50 CW-170
Dover Chemical Corp., Paroil 170HV Paroil 160 Paroil 152 Chlorez 700 Paroil 150S Paroil 140
USA Paroil 1048
Plastifax, Inc., USAb Plastichlor P-70 Plastichlor P-59 Plastichlor 50-220 Plastichlor
P-65 42-170
ICI, Australia; Canada; Cereclor 70L Cereclor 60L Cereclor S52 Cereclor 70 Cereclor 48 Cereclor 42
UK; France
Neville Chemical Co., Unichlor 60L-60 Unichlor 50L-65 Unichlor 50-450 Unichlor 40-170
USAb Unichlor 40-150
Pearsall Chemical Co., FLX-0012 FLX-0008 CPF-0020 CPF-0004
USA CPF-0003 CPF-0001
Hüls AG, Germanyb Chlorparaffin Chlorparaffin Chlorparaffin Chlorparaffin
70C 60C 52G 40N
Dynamit Nobel, Germanyb Witaclor 171 Witaclor 160 - Witaclor 350 Witaclor 549 Witaclor 540
Witaclor 163 Witaclor 352
Caffaro, Italy Cloparin D70 Cloparin 1059 Cloparin 50 Cloparin S70 Cloparin P42
Table 2. (Cont'd)
Average molecular formula C12H15Cl11 C12H19Cl7 C15H26Cl6 C24H29Cl21 C24H42Cl8 C24H44Cl6
Chlorine content (% w/w) 70 60-65 50-52 70 48-54 40-42
Hoechst AG, Germany Chlorparaffin Hordaflex LC60 Chlorparaffin Chlorparaffin Chlorparaffin
Hoechst 70 Hoechst 52fl Hoechst 70fest Hoechst 40fl
Rhône-Poulenc, France Alaiflex 67B2 Ribeclor 60B2 Alaiflex 50A3 Alaiflex 40A8
a Other producers include Bann Quimica (Brazil), Excel Industry (India), Ajinomoto (Japan), Tosoh (Japan), Asahi Denka (Japan),
Plasticlor (Mexico), NCP (South Africa)
b These companies have ceased production of chlorinated paraffins.
Table 3. Composition of paraffins obtained by dechlorination of
different chlorinated paraffin preparations (Zitko, 1974b)
Chlorinated Percentage of each paraffin
paraffin
C21 C22 C23 C24 C25 C26 C27 C28
Chloroparaffin, 4.5 10.0 15.7 19.3 18.5 15.3 9.8 6.7
40%
Clorafin 40 3.7 8.2 14.0 17.5 19.2 17.4 12.4 7.6
CP 40 3.9 9.1 14.9 19.2 19.8 18.0 15.1 -
Cereclor 42 3.6 8.8 14.7 18.6 19.5 17.2 11.5 6.0
Chloroparaffin, 7.4 14.9 20.7 23.1 19.9 14.0 - -
50%
2.2 Chemical and physical properties
Chlorinated paraffins are viscous, colourless or yellowish, dense
oils, except for the chlorinated paraffins of long carbon chain length
(C20-C30) with high chlorine content (70%), which are solid.
Chlorinated paraffins have a characteristic slight and not unpleasant
odour (Hardie, 1964). The odour is probably due to small quantities
of products of lower relative molecular mass with small but measurable
vapour pressures (Howard et al., 1975). Chlorinated paraffins
themselves have very low vapour pressures. The medium chain length
C14-17;52% Cl has a vapour pressure of approximately 2 × 10-4 Pa at
20°C (1-2 × 10-6 mmHg) (Campbell & McConnell, 1980), and the long
chain length C23;42-54% Cl approximately 3 × 10-3 Pa when measured at
65°C (2 × 10-5 mmHg) (Hardie, 1964). The chemical and physical
properties of chlorinated paraffins are determined by the carbon chain
length of the paraffin and the chlorine content. Increases in the
carbon chain length and chlorination degree of a particular paraffin
increase the viscosity and density but reduce the volatility.
Chlorinated paraffins are practically insoluble in water, but
many products can be emulsified with water (approximately 70/30
chlorinated paraffin to water). The water solubility of 14C-labelled
polychloroundecane (C11;59% Cl) is reported to be 150-470 µg/litre,
polychloropentadecane (C15;51% Cl) 5-27 µg/litre and the poly-
chloropentacosanes (C25;43% Cl) < 5-6.4 µg/litre and (C25;70%
Cl) < 5-5.9 µg/litre, depending on analytical method (Madeley &
Gillings, 1983). Campbell & McConnell (1980) reported the solubility
of C16;52% Cl to be 10 µg/litre in freshwater and 4 µg/litre in
seawater. The solubility of C25;42% Cl was reported to be 3 µg/litre
in seawater. Chlorinated paraffins are also practically insoluble in
lower alcohols, glycerol and glycols, but are soluble in chlorinated
solvents, aromatic hydrocarbons, ketones, esters, ethers, mineral oil
and some cutting oils. They are moderately soluble in unchlorinated
aliphatic hydrocarbons (Houghton, 1993). Some physical properties of
typical commercial chlorinated paraffins are summarized in Table 4.
Assuming a water solubility of 5 µg/litre and a vapour pressure
of 2 × 10-4 Pa as typical of a 52% chlorinated intermediate chain
length paraffin, a Henry's Law constant of 10.9 may be calculated
(Willis et al., 1994).
A key property of chlorinated paraffins, particularly the high
chlorine grades, is their nonflammability. This is due to the ability
of chlorinated paraffins to release hydrochloric acid at elevated
temperatures, and the hydrochloric acid inhibits the radical reaction
in a flame. This property is considerably enhanced by the addition of
antimony trioxide (Houghton, 1993) or other additives. Chlorinated
paraffins are generally unreactive and stable in normal temperatures,
but decompose significantly at temperatures above 300°C with the
release of hydrochloric acid (Strack, 1986). Prolonged exposure
to light can also cause dehydrochlorination. Degradation by
dehydrochlorination can be accelerated at elevated temperatures in
the presence of aluminium, zinc, and iron oxide or chloride (Howard
et al., 1975; Houghton, 1993). Dehydrochlorination leads to darkening
of the material.
2.3 Analysis
The analysis of chlorinated paraffins is very difficult owing to
the many congeners present in the products. The properties of these
congeners cover wide ranges, which makes it difficult to separate the
chlorinated paraffins from other compounds that may interfere in the
analysis.
Table 4. Physical properties of selected commercial chlorinated paraffinsa
Paraffin Chlorine Colour hazen Viscosityb Densityb Thermal stabilityc Volatilityd Refractive Log Powe
feedstock content (APHA) (Pa.s) (g/ml) (% w/w HCl) (% w/w) index
% (w/w)
C10-C13 50 100 0.08 1.19 0.15 16.0 1.493 4.39-6.93
56 100 0.8 1.30 0.15 7.0 1.508 NRg
60 125 3.5 1.36 0.15 4.4 1.516 4.48-7.38
63 125 11.0 1.41 0.15 3.2 1.522 5.47-7.30
65 150 30.0 1.44 0.20 2.5 1.525 NR
70 200 8.0f 1.50 0.20 0.5 1.537 5.68-8.01h
C14-C17 40 80 0.07 1.10 0.2 4.2 1.488 NR
45 80 0.2 1.16 0.2 2.8 1.498 5.52-8.21
52 100 1.6 1.25 0.2 1.4 1.508 5.47-8.01
58 150 40.0 1.36 0.2 0.7 1.522 NR
Wax C18-C20 47 150 1.7 1.21 0.2 0.8 1.506 NR
50 250 18.0 1.27 0.2 0.7 1.512 NR
Wax (C> 20) 42 250 2.5 1.16 0.2 0.4 1.506 9.29->12.83h
48 300 28.0 1.26 0.2 0.3 1.516 8.69-12.83
70 100i j 1.63 0.2 NR - NR
a Data from Houghton (1993) f At 50°C
b At 25°C unless otherwise noted g NR = not reported
c Measured in a standard test for 4 h at 175°C h Data from Cereclor 42
d Measured in a standard test for 4 h at 180°C i 10 g in 100 ml toluene solvent
e Octanol:water partition coefficients. From: Renberg et al (1980) j Solid, softening point = 95-100°C
2.3.1 Sampling
To prevent contamination by trace amounts of chlorinated
paraffins, samples or their extracts must not be allowed to come into
contact with any plastic (especially PVC) container, stopper, cap
liner or tubing, because these may contain chlorinated paraffins
(Hollies et al., 1979). All solvents should be rigorously tested
before use, and it is recommended that glass distilled solvents are
used. All glassware should be decontaminated before use by heating at
250°C for 24 h. Water and sediment samples should be stored at
ambient temperatures, and should be analysed within a month of
sampling.
Treatment of samples for the extraction of chlorinated paraffins
is described in Table 5.
2.3.2 Analytical methods
Methods used for detection of chlorinated paraffins in various
samples are shown in Table 5.
Hollies et al. (1979) determined C13-17 and C20-30 chlorinated
paraffin after clean-up of the samples on aluminium oxide columns.
The chlorinated paraffin fraction was then applied on a silica gel
thin-layer chromatography (TLC) plate. After forward elution with
n-hexane and subsequently with toluene, and backward elution with
n-hexane, chloride from the chlorinated aliphatics was transferred
to an aluminium oxide plate at 240°C and developed with silver
nitrate. The resulting spots were quantified by visual comparison
with spots of known amounts of reference materials. Although the
procedure is complicated and involves several evaporations to dryness,
good recoveries were reported. Possible interference from a number of
other chlorinated compounds was investigated and found to be
negligible, but the method must still be regarded as fairly
non-specific.
Gas chromatographic analysis of chlorinated paraffin, using
microcoulometric detection, has been described by Zitko (1973). This
method gives badly resolved chromatograms and there is a considerable
risk of interference from other halogenated compounds. Owing to high
temperatures in the gas chromatographic system there is also a risk of
dehydrochlorination of the chlorinated paraffin congeners. In a later
study (Zitko & Arsenault, 1977), interference from other compounds was
avoided by a solvent partitioning clean-up procedure.
Table 5. Analytical methods for the determination of chlorinated paraffins in various samplesa
Sample Preparation method Analytical Sample detection Recovery Reference
matrix methodb limitb
Water Extract with petroleum spirit; concentrate; purify by TLC 500 ng/litre 90% Hollies et
aluminium oxide chromatography, elute with toluene; al. (1979)
dry; dissolve in petroleum spirit
Water Extract with hexane; purify by aluminium oxide GC/ECD 3 ng/litre NR Kraemer &
chromatography; elute with hexane/dichloromethane Ballschmiter
(4%); purify by silica gel chromatography, elute with (1987)
hexane:dichloromethane (19:1); dissolve in isooctane.
Water Extraction with hexane (particle phase Soxhlet GC/ approx. 92-120% Steele et
extracted), silica gel and aluminium oxide column MS-NCI 1 µg/litre al. (1988)
chromatography
Biological Homogenize; extract with petroleum spirit:acetone TLC 50 µg/kg 80-90% Hollies et
material (2:1); dry; dissolve in petroleum spirit; extract with al. (1979)
dimethylformamide; wash; back-extract with Na2SO3
solution and petroleum spirit; purify by silica gel
chromatography, elute with CCl4; dry; dissolve in
acetone; extract with petroleum spirit:acetone (1:4)
Cod muscle Homogenize in n-hexane:acetone (1:2.5, v:v); extract GC/MS NR 98-114% at Jansson et
tissue with 10% diethyl ether in n-hexane; evaporate; dissolve 0.465 µg/sample al. (1991)
in dichloromethane:n-hexane (1:1, v/v); purify by gel and 89-92% at
permeation chromatography; concentrate; extract with 2.33 µg/sample
sulfuric acid; concentrated in organic phase
Adipose Homogenize in dichloromethane; percolate through GC/MS 5 ng 80% Schmid &
tissue anhydrous Na2SO4; remove solvent; dissolve residue in Müller (1985)
pentane; wash, dry and concentrate; purify by alumina
chromatography
Table 5. (Cont'd)
Sample Preparation method Analytical Sample detection Recovery Reference
matrix methodb limitb
Mineral oil Extract fish in cyclohexane; introduce extract or MS-NCI NR NR Gjos &
and fish mineral oil sample directly into mass spectrometer Gustavsen
extract (1982)
Fish fillets Homogenize in petroleum ether; clean-up by irradiating GC/CD NR > 90% Friedman &
extracts with high-intensity UV light (90 min, < 20°C) Lombardo
in petroleum ether (1975)
Sewage Homogenize in acetone; extract with pentane; wash, dry GC/MS 5 ng NR Schmid &
sludge and concentrate; purify by alumina chromatography Müller (1985)
Sediment Dry at 70°C; extract with petroleum spirit; TLC 50 µg/kg 80% Hollies et
concentrate; purify by aluminium oxide al. (1979)
chromatography, elute with toluene; dry; dissolve
in petroleum spirit
Sediment Extract with acetone:hexane (1:1, v:v); wash, dry GC/MS 5 ng NR Schmid &
and concentrate; purify by alumina chromatography Müller (1985)
Sediment Soxhlet extraction with hexane, silica gel and GC/ approx. 52-64% Steele et
aluminium oxide column chromatography MS-NCI 1 µg/litre al. (1988)
a Modified from IARC (1990)
b GC/MS = gas chromatography/mass spectrometry; GC/CD = gas chromatography/coulometric detection;
GC/ECD = gas chromatography/electron capture detection; MS-NCI = negative-ion chemical ionization mass spectrometry;
TLC = thin-layer chromatography; NR = not reported
Attempts have been made to reduce the complexity of chlorinated
paraffin mixtures by reductive dechlorination (Cooke & Roberts, 1980;
Roberts et al., 1981; Sistovaris & Donges, 1987). This method gives
information on the "carbon skeleton" of the chlorinated paraffin
compounds but no information on the chlorine content, and it is
difficult to separate the response from that of unchlorinated
hydrocarbons.
Negative ion chemical ionization mass spectrometry (MS-NCI) was
used by Gjös & Gustavsen (1982). In this method the chlorinated
paraffin fractions are introduced directly into the ion source of the
mass spectrometer. As the whole sample is analysed in a very short
time, the concentration in the ion source is high and the sensitivity
can therefore be high. A serious disadvantage is that all other
compounds in the sample come into the mass spectrometer at the same
time, the risk of interference is high and an extensive clean-up of
the samples is needed.
Gas chromatography utilizing MS-NCI for the detection was used by
Schmid & Müller (1985). A fairly simple clean-up based on adsorption
chromatography on aluminium oxide was used, but unfortunately this
has been impossible to reproduce (Jansson, personal communication).
GC/MS-NCI was also used by Steele et al. (1988) to determine
chlorinated paraffins after clean-up of samples on silica gel and
aluminium oxide columns. They used low inlet temperatures in the
gas chromatograph to avoid thermolysis of the analysed compounds.
The use of low temperatures and short capillary columns further
decreases the risk of temperature-related break-down of chlorinated
paraffins during gas chromatographic analysis (Jansson et al., 1991).
In this method a gel permeation column was also used to avoid
interference from other chlorinated compounds, and the Cl2- and
HCl2- ions were used to detect aliphatic chlorinated compounds
selectively.
Developments in chlorinated paraffin analysis have improved
both selectivity and sensitivity. However, although the reliability
of results is now better, these are only estimates of the real
concentrations as it is impossible to detect the individual substances.
3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1 Natural occurrence
Chlorinated paraffins are not known to occur naturally.
3.2 Anthropogenic sources
3.2.1 Production levels and processes
Liquid chlorinated paraffins were first used in large amounts
during the period 1914-1918 as solvents for Dichloramine T in
antiseptic nasal and throat sprays (Howard et al., 1975). The
commercial production of chlorinated paraffins for use as extreme
pressure additives in lubricants started around 1930 (Schenker, 1979).
Estimated data on the production of chlorinated paraffins are
shown in Table 6. Chlorinated paraffins are produced in Australia,
Brazil, Bulgaria, Canada, China, Germany, France, India, Italy, Japan,
Mexico, Poland, Romania, Spain, Slovakia, South Africa, China
(Province of Taiwan), Thailand, the United Kingdom, the USA, and the
former USSR. However, this may not be a complete list of producer
countries. It is believed that 50% of the chlorinated paraffins
produced in the world have carbon chain lengths of between 14 and 17
and a chlorine content of between 45 and 52%. In the United Kingdom
approximately 80% of the total production of chlorinated paraffins is
concentrated on the C14-17 chain length. About 15% of the European
consumption of chlorinated paraffins is estimated to be C10-13, 70%
C14-17 and 15% C20-30 (Willis et al., 1994).
Chlorinated paraffins are produced by reacting liquid paraffin
fractions obtained from petroleum distillation with pure chlorine gas
by a reaction mechanism involving free radicals (Schenker, 1979;
Houghton, 1993). The reaction is exothermic. At a chlorine content
above approximately 54% further chlorination is slow and difficult.
In the production of resinous chlorinated paraffins containing
> 70% Cl, a solvent is usually added to decrease the viscosity
(Howard et al., 1975). Carbon tetrachloride has been the most
commonly used solvent, and may be present in trace amounts in the
final product, although alternative production methods are being
developed because of the phase-out of carbon tetrachloride under the
Montreal Protocol (D. Farrer, personal communication to the IPCS,
1995).
The substituted chlorine atoms are probably randomly distributed,
and at a chlorination of 72% all of the carbon atoms are singly
chlorinated. Further chlorination is difficult since the first
chlorine substitution decreases the reactivity of the other hydrogens
on a particular carbon atom (Hardie, 1964).
Table 6. Estimated production of chlorinated paraffins
Production References
(tonnes/year)
Canada - 1990 2900 Camford Information
Services (1991)
Germany - 1990/1991 20 000-30 000 BUA (1992)
United Kingdom - 1992 50 000 Willis et al. (1994)
USA - 1977 37 000 Schenker (1979)
USA - 1983 45 000 NTP (1986a)
USA - 1987 45 000 IARC (1990)
USA - 1990 26 000 US EPA (1993)
North America - 1978 60 000 Zitko (1980)
Western Europe - 1978 105 000 Zitko (1980)
Western Europe - 1985 95 000 IARC (1990)
World, excluding 230 000 Campbell &
Eastern Europe - 1977 McConnell (1980)
World - 1985a 300 000 Strack (1986)
a Excluding the former Soviet Union and the People's Republic of China.
Depending on producer and paraffin feedstock, the temperature of
the chlorination reaction is usually kept at 80-100°C to decrease the
viscosity but at a temperature where the decomposition of the product
is not extensive (Schenker, 1979; Houghton, 1993). Since the reaction
is exothermic heat removal is important in the process. Ultraviolet
light is often used as a catalyst (Schenker, 1979; Houghton, 1993).
Metal catalysts are avoided since they may promote dechlorination of
the chlorinated paraffins. Since for each tonne of chlorinated
paraffin produced, approximately half a tonne of hydrochloric acid is
generated, the linings of the reactor vessels must be chemically inert
to avoid the formation of metal chlorides, which cause darkening of
the product by decomposition (Strack, 1986; Houghton, 1993).
Additional procedures used in the production of the C20-30;70% Cl solid
grade are stripping of the solvent and grinding of solid products
(Schenker, 1979).
3.2.2 Uses
Chlorinated paraffins are used as secondary plasticizers for
polyvinyl chloride (PVC) and can partially replace primary
plasticizers such as phthalates and phosphate esters (Houghton, 1993).
The use of chlorinated paraffins has the advantage in comparison with
conventional plasticizers of both increasing the flexibility of
the material as well as increasing its flame retardancy and
low-temperature strength (Howard et al., 1975). Chlorinated paraffins
are also used as extreme pressure additives in metal-machining fluids
or as metal-working lubricants or cutting oils because of their
viscous nature, compatibility with oils, and property of releasing
hydrochloric acid at elevated temperatures. The hydrochloric acid
reacts with metal surfaces to form a thin but strong solid film of
metal chloride lubricant. In Sweden, the use of chlorinated paraffins
in metal-working fluids has been reduced from 680 tonnes (1986) to
139 tonnes (1993) as a part of a risk reduction programme (Swedish
Environmental Protection Agency, 1994). They are added to paints,
coatings and sealants to improve resistance to water and chemicals,
which is most suitable when they are used in marine paints, as
coatings for industrial flooring, vessels and swimming pools (e.g.,
rubber and chlorinated rubber coatings), and as road marking paints.
The flame-retarding properties of highly chlorinated paraffins make
them important as additives in plastics, fabrics, paints and coatings.
The most effective fire-retardant action is obtained with a high
degree of chlorination.
By the late 1970s approximately 50% of chlorinated paraffins in
the USA was used as extreme pressure lubricant additives in the
metal-working industry; 25% was used in plastics and fire-retardant
and water-repellant fabric treatments, and the rest was used in paint,
rubber, caulks and sealants (Schenker, 1979). In the United Kingdom,
65-70% of the consumed chlorinated paraffins is used as a secondary
plasticizer in PVC, about 10% in paint, about 10% in metal-cutting
lubricants and about 10% in flame retardants and sealants (Willis et
al., 1994). In Canada approximately 55% of the chlorinated paraffins
is used as plasticizers and 35-40% as high-pressure lubricant
additives (Camford Information Services, 1991). Some examples of
applications for chlorinated paraffins of different chain-lengths are
shown in Table 7.
3.2.3 Loss into the environment
Since chlorinated paraffins are produced without contact with
water, the possibility of leakage into the environment by direct water
discharge is low. After chlorination the solvent is removed and
residual amounts of chlorine gas and hydrogen chloride are removed by
blowing air or other gases through the product. This could possibly
lead to some loss into the air, but since the chlorine gas and
hydrochloric acid are recovered and the volatility of chlorinated
paraffins is very low, the loss is likely to be very low (Howard et
al., 1975). Emission into the atmosphere during manufacture in
Germany in 1990 was estimated to be about 250 kg/year (BUA, 1992). It
is possible that chlorinated paraffins may be a by-product during
chlorination of other hydrocarbon feedstocks if paraffins are present
as contaminants. This could lead to possible environmental
contamination.
Table 7. Uses of various chlorinated paraffins
Paraffin Chlorination (%) Application
feedstock
C10-13 plasticizer for PVC or plastics
C10-13 metal-working fluids; sealants
C10-13 approx. 70 flame retardants for rubber and soft plastics
C14-17 40-60 extreme pressure additives to metal-machining
fluids, pastes, emulsions and lubricants
C14-17 45-52 the chlorinated paraffin most frequently used as a
(40-50) plasticizer for plastics; also used for sealants
C18-30 approx. 70 flame retardants for rigid plastics such
as polyesters and polystyrene
C> 20 plasticizer for PVC or plastics
Some loss into the environment could be expected during transport
and storage. If the drums which are used for the transport of
chlorinated paraffins are cleaned for further use environmental
release might occur. Soil could be contaminated if empty drums are
dumped at landfills. Spills may occur, but clean-up using an
adsorbent material is easy. The adsorbent material would probably
be deposited in a landfill, which in turn could lead to possible
environmental contamination.
The uses of chlorinated paraffins probably provide the major
source of environmental contamination. When chlorinated paraffins are
used as plasticizers or additives in coatings, they are effectively
dissolved in the polymers and will therefore leak into the environment
only very slowly. However, polymers containing chlorinated paraffins
will act as sources of chlorinated paraffins for centuries after
disposal. A more likely route of leakage of chlorinated paraffins
into the environment would be the improper disposal of oils containing
chlorinated paraffins (Campbell & McConnell, 1980) or disposal of
chlorinated paraffins of low quality (Howard et al., 1975). Loss of
chlorinated paraffins by removal from paints and coatings may also
contribute to environmental contamination.
It is estimated that a maximum of 55% of the cutting and
lubricating oils sold to the engineering industry in Sweden becomes
waste. The rest is consumed or released into the air and water (KEMI,
1991). The largest consumer of chlorinated paraffins in Sweden
(1400 tonnes/year) has estimated its emission of chlorinated paraffins
to be 90 kg/year (0.06 g emission/kg chlorinated paraffin produced)
(KEMI, 1991).
Disposal of wastes containing chlorinated paraffins occurs
through resource recovery, destructive incineration or landfill,
usually on disposal sites for special wastes and in compliance with
local regulations. Owing to their thermal instability, chlorinated
paraffins are expected to be degraded by incineration at low
temperatures and thus would not be expected to volatilize in exhaust
gases from an incinerator. However, in a study by Bergman et al.
(1984), chlorinated aromatic compounds such as PCBs, naphthalenes and
benzenes were formed by pyrolysis of chlorinated paraffins (see
section 4.2.1) although the conditions used were not identical to the
operation conditions of waste incineration plants. Chlorinated
paraffins are not expected to be formed de novo. The disposal of
chlorinated paraffins in landfills may give rise to leaching into
water, but owing to the low water solubility and strong adsorption
onto solids the amounts reaching water are likely to be low.
4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION AND TRANSFORMATION
4.1 Transport and distribution between media
Considering the low vapour pressure (2 × 10-4 Pa at 20°C for
C14-17;52% Cl to 3 × 10-3 Pa at 65°C for C23;42-54% Cl), low water
solubility (3 to 470 µg/litre) and highly lipophilic nature of
chlorinated paraffins (log Pow values range from 4.39 to > 12.83),
it is likely that they will distribute mainly to the soil/sediment
phase with very little volatilization occurring. Chlorinated
paraffins are likely to be transported in water as suspended
particles, and in air as dust particles and possibly in the vapour
phase. However, no experimental data on this subject have been
reported.
4.2 Transformation
4.2.1 Abiotic transformation
No experimental data on the chemical stability of chlorinated
paraffins under simulated environmental conditions have been reported.
However, their chemical reactivities suggest that they do not
hydrolyse, oxidize or react by other mechanisms at significant rates
under normal temperatures and neutral conditions (Howard et al.,
1975). Dehydrochlorination of chlorinated paraffins may possibly
occur naturally in the presence of metal ion contamination.
Because of the high adsorption tendency of chlorinated paraffins,
gas phase reactions are assumed to contribute only little to
degradation in the atmosphere (BUA, 1992). However, calculated
half-lives for chlorinated paraffins in air are reported to range from
0.85 to 7.2 days (Slooff et al., 1992). The theoretical values are
shown in Table 8.
The thermal degradation by pyrolysis of chlorinated paraffins at
various temperatures (300, 500, 700°C) and times (10 sec to 20 min)
was studied by Bergman et al. (1984). The chlorinated paraffins were
totally degraded, and, depending upon degree of chlorination of the
chlorinated paraffin, several aliphatic and aromatic degradation
products, such as polychlorinated biphenyls (PCBs), naphthalenes and
benzenes, were detected. As much as 10 g of PCBs per kg chlorinated
paraffin could be found after thermal degradation of C12;70% Cl
(temperature not specified). Smaller amounts of compounds were formed
at lower temperatures. Considering these results, processes where
chlorinated paraffins are subjected to temperatures above 300°C could
lead to environmental contamination and exposure to more persistent
and toxic substances than the original chlorinated paraffins.
Table 8. Photochemical degradation of chlorinated paraffins in the
atmosphere (From: Slooff et al., 1992)
Carbon chain length Koh (cm3/mol per sec) Half-life (days)
C10-C13 9.0-14.9 × 10-12 1.2-1.8
C14-C17 14.9-18.9 × 10-12 0.85-0.8
C15-C30 20.2-31.1 × 10-12 0.5-0.8
not specified 2.2-18.8 × 10-12 0.85-7.2
4.2.2 Biodegradation
Chlorinated paraffins are generally stable in the natural
environment.
4.2.2.1 Short chain length chlorinated paraffins
A short chain length paraffin (C10-12) with 58% chlorination
(CP-SH) was not readily biodegraded by activated sludge, under either
aerobic or anaerobic conditions, over a 28-day period in an inherent
biodegradability (modified Zahn-Wellens) test (Street & Madeley,
1983a,b) or a 51-day period in a coupled units test (Mather et al.,
1983).
4.2.2.2 Long chain length chlorinated paraffins
Zitko & Arsenault (1977) studied sediment spiked with 596 mg/kg
dry weight of Cereclor 42 C24;42% Cl, CP-LL) or 357 mg/kg dry weight
of Chlorez 700 (C24;70% Cl, CP-LH), which are both long chain length
chlorinated paraffins but have different chlorine contents. There was
no clear trend in the results but they indicated that after 4 weeks
the highly chlorinated Chlorez 700 was degraded to a greater extent
than Cereclor 42. The rate of degradation seems to have been higher
under anaerobic conditions.
4.2.2.3 Comparative studies
In another study, the microbial degradation of several short,
intermediate and long chain length chlorinated paraffins of different
chlorination degree at concentrations of 2, 10 and 20 mg/litre was
examined in a 25-day biochemical oxygen demand (BOD) test (Madeley &
Birtley, 1980). The degradation rate appeared to decrease with
increasing carbon chain length and chlorination degree, and the short
chain chlorinated paraffins with less than 50% Cl were degraded most
rapidly and completely. It can be concluded from the results that
chlorinated paraffins with low chlorine contents (< 50% wt Cl) and,
especially, short chain chlorinated paraffins, biodegrade slowly in
the environment, particularly in the presence of adapted microbial
populations, but that chlorinated paraffins with higher chlorine
contents are unlikely to biodegrade under aerobic conditions.
Anaerobic microorganisms did not degrade Cereclor 42 (C24;42% Cl) in
30 days when readily biodegradable alternative carbon sources were
available.
Omori et al. (1987) found that bacterial strains isolated from
the soil degraded various chlorinated paraffins by dechlorination in
the presence of n-hexadecane. In a mixed culture of four strains,
more than 50% of the chlorine was removed from the shorter paraffins
with lower chlorine content (C14;43% Cl, CP-ML and C15;50% Cl, CP-MH)
within 36 h. Lower amounts of chlorine were removed from the
chlorinated paraffins with longer chain lengths. Activated sludge
from a sewage treatment plant in Tokyo acclimatized to n-hexadecane
for 60 days showed only a limited amount (2%) of dechlorination of the
chlorinated paraffins. The bacterial dechlorination concerned the
terminal chlorine, which produced 2- or 3-chlorinated fatty acids via
ß-oxidation.
4.3 Bioaccumulation and biomagnification
4.3.1 Summary
Chlorinated paraffins of short chain length accumulate in mussels
and fish to a higher degree than intermediate and long chain length
chlorinated paraffins.
Data on bioaccumulation of chlorinated paraffins by aquatic
organisms are summarized in Table 9. Bioconcentration factors (BCFs)
may be uncertain since the applied doses exceeded the water solubility
in several experiments.
Table 9. Bioconcentration factors for some chlorinated paraffins
Species Chlorinated paraffina Exposure Bioconcentration Reference
Concentration Duration factor
(µg/litre) (days) (whole animal)b
Marine diatom C10-12;58% Cl (CP-SH) 1.4 10 < 1 Thompson & Madeley (1983b)
(Skeletonema costatum) 17.8 10 3.5
Freshwater green alga C10-12;58% Cl (CP-SH) 35 10 1.5 Thompson & Madeley (1983d)
(Selenastrum capricornutum) 140 10 7.6
150 10 4.1
Mussel C10-12;58% Cl (CP-SH) 2.3 147 40 900e Madeley et al. (1983a)
(Mytilus edulis) 10 91 24 800e
C10-12;58% Cl (CP-SH) 13 60 25 292e Madeley & Thompson (1983a)
130 60 12 177e
C12;69% Cl (CP-SH) 0.13 28 138 000e Renberg et al. (1986)
C16;34% Cl (CP-ML) 0.13 28 6920e
C14-17;52% Cl (CP-MH) 220 60 2856e Madeley & Thompson (1983b)
3800c 60 429e
C22-26;43% Cl (CP-LL) 120 60 1158e Madeley & Thompson (1983c)
2180c 60 261e
C22-26;70% Cl (CP-LH) 460 60 341e Madeley & Thompson (1983d)
1330c 60 223e
Table 9. (Cont'd)
Species Chlorinated paraffina Exposure Bioconcentration Reference
Concentration Duration factor
(µg/litre) (days) (whole animal)b
Rainbow trout C10-12;58% Cl (CP-SH) 3.1 168 3550e Madeley & Maddock (1983b)
(Oncorhynchus mykiss) 14 168 5260e
C10-12;58% Cl (CP-SH) 33 60 7155e Madeley & Maddock (1983c)
3050c 60 1173e
C14-17;52% Cl (CP-MH) 1050c 60 45e Madeley & Maddock (1983c)
4500c 60 67e
C22-26;43% Cl (CP-LL) 970 60 18e Madeley & Maddock (1983c)
4000c 60 38e
C20-30;70% Cl (CP-LH) 840 60 54e Madeley & Maddock (1983c)
3800c 60 32e
Bleaks C10-13;49% Cl (CP-SL) 125 14 770d,f Bengtsson et al. (1979)
(Alburnus alburnus) 59% Cl (CP-SH) 125 14 740d,f Bengtsson et al. (1979)
71% Cl (CP-SH) 125 14 140d,f Bengtsson et al. (1979)
C14-17;50% Cl (CP-MH) 125 14 30d,f Bengtsson et al. (1979)
C18-26;49% Cl (CP-LL) 125 14 7d,f Bengtsson et al. (1979)
a The classification of chlorinated paraffins is given in Table 1
b Ratio of the concentration of the chemical in the organism to the concentration of the chemical in the environment or food
c May exceed water solubility
d BCFs calculated by Zitko (1980)
e BCFs based on radioactivity (14C)
f BCFs based on parent compounds
4.3.2 Aquatic vertebrates
4.3.2.1 Short chain length chlorinated paraffins
In a study by Lombardo et al. (1975), fingerling rainbow trout
(Oncorhynchus mykiss) were fed a diet containing 10 mg/kg Chlorowax
500C (C12;60% Cl, CP-SH) for 82 days. Samples of 20 exposed and 10
control fish were collected at approximately 2-week intervals during
the time-period and analysed for chlorinated paraffin content by
microcoulometric gas chromatography (Friedman & Lombardo, 1975). The
tissue level of chlorinated paraffins rose during the treatment period
to 1.1 mg/kg (on tissue basis) or 18 mg/kg (on fat basis) after 82
days (detection level: 0.5 mg/kg). The experiment had to be
terminated owing to the failure of the water supply, and it was not
possible to determine whether a steady-state level had been reached.
In studies (Madeley & Maddock, 1983b) on rainbow trout
(Oncorhynchus mykiss) exposed to measured concentrations of 3.1 and
14.3 µg/litre of 14C-labelled C10-12; 58% Cl (CP-SH) for a period of
168 days, BCF value of 1300 (low dose) and 1600 (high dose) were
observed in the flesh, 2800 (low dose) and 16 000 (high dose) in the
liver, and 11 700 (low dose) and 15 500 (high dose) in the viscera;
all values were determined from radioactivity measurements. The BCF
for the whole body was 3350 (low dose) and 5260 (high dose)
(calculated values). Half-lives for elimination in different organs
were calculated to be the following: liver 9.9 (low dose) and 11.6
days (high dose), viscera 23.1 (low dose) and 23.9 days (high dose),
and flesh 16.5 (low dose) and 17.3 days (high dose).
Rainbow trout (Oncorhynchus mykiss) were exposed to measured
concentrations ranging from 33 to 3050 µg/litre of C10-12;58% Cl
(CP-SH) for 60 days (Madeley & Maddock, 1983c). BCFs, which were
determined in whole fish samples at the end of the test, were 7155
(low dose) and 1173 (high dose) based on radioactivity measurements,
and 7273 (low dose) and 574 (high dose) based on parent compound
analysis. Parent compound analysis was performed using a modification
of the method of Hollies et al. (1979) (see section 2.3.2).
4.3.2.2 Intermediate chain length chlorinated paraffins
After 60 days exposure of rainbow trout (Oncorhynchus mykiss)
to measured concentrations of 1050 and 4500 µg/litre of intermediate
length (C14-17) chlorinated paraffins with 52% Cl (CP-MH), whole body
BCFs of 45 (low dose) and 67 (high dose) based on radioactivity
measurements, and of 32 (low dose) and 42 (high dose) based on parent
compound analysis were determined (Madeley & Maddock, 1983c). The
BCFs were determined at the end of the exposure period. Parent
compound analysis was performed using a modification of the method of
Hollies et al. (1979) (see section 3.2.3).
4.3.2.3 Long chain length chlorinated paraffins
Juvenile Atlantic salmon (Salmo salar) were exposed to Cereclor
42 (C24;42% Cl, CP-LL) or Chlorez 700 (C24;70% Cl, CP-LH) by uptake
from suspended solids or from food (Zitko, 1974a). The fish were
treated with either 1000 µg/litre of contaminated suspended solids for
48 h and 144 h, or to 10 mg/kg or 100 mg/kg of contaminated food for
181 days with a subsequent elimination period of 74 days. No or very
low accumulation of the chlorinated paraffins was observed. However,
the analytical method used determined the amount of chlorine and not
of chlorinated paraffin; this method has been considered as nonspecific
and of low sensitivity.
After 60 days exposure of rainbow trout (Oncorhynchus mykiss)
to long chain chlorinated paraffins with 43% Cl (CP-LL) (970 or
4000 µg/litre) or 70% Cl (CP-LH) (840-3800 µg/litre), whole body BCFs,
based on measured exposure concentrations, of 17.9 (low dose, 43% Cl),
37.6 (high dose, 43% Cl) and 53.8 (low dose, 70% Cl) and 32.5 (high
dose, 70% Cl) were determined at the end of the study when measured as
radioactivity. BCF values of 3.6 (low dose, 43% Cl), 9.0 (high dose,
43% Cl), 42.8 (low dose, 70% Cl) and 31.6 (high dose, 70% Cl), based
on parent compound analysis, were determined (Madeley & Maddock,
1983c).
4.3.3 Aquatic invertebrates
4.3.3.1 Short chain length chlorinated paraffins
After 60 days exposure of mussels (Mytilus edulis) to a short
chain length paraffin with 58% Cl (CP-SH) at measured concentrations
of 13 and 130 µg/litre, whole body BCFs were 25 292 and 12 177,
respectively, based on radioactivity measurements, and 20 000 and
7923 when measured as parent compound (Madeley & Thompson, 1983a).
After exposure of mussels (Mytilus edulis) for 147 days to
14C-labelled short chain length chlorinated paraffin with 58% Cl
(CP-SH) followed by a depuration period of 98 days (measured exposure
dose: 2.3 µg/litre), or for 91 days followed by 84 days of depuration
(measured exposure dose: 10.1 µg/litre), plateau levels of the
chlorinated paraffin in tissues were reached. Bioconcentration
factors (BCFs) at the plateau levels were 40 900 for whole mussel
tissue after exposure to 2.35 µg/litre and 24 800 after exposure to
10.1 µg/litre based on wet tissue basis. Of the different organs the
digestive glands had the highest BCF values of 226 000 (low exposure)
and 104 000 (high exposure). Half-lives for the chlorinated paraffin
in whole mussel tissue were 9.2-9.9 days (10.1 µg/litre) and 13.1-19.8
days (2.35 µg/litre) (Madeley et al., 1983a).
4.3.3.2 Intermediate chain length chlorinated paraffins
After 60-day exposures of mussels (Mytilus edulis) to
intermediate chain length paraffin with 52% Cl (CP-MH) at measured
concentrations of 220 and 3800 µg/litre (which was above the limit
of solubility in water), whole body BCFs were 429-2856 based on
radioactivity measurements and 339-2182 based on parent compound
analysis (Madeley & Thompson, 1983b).
4.3.3.3 Long chain length chlorinated paraffins
In mussels exposed to measured concentrations of 120-2180
µg/litre of long chain length chlorinated paraffin with 43% Cl (CP-LL)
and 460-1330 µg/litre of long chain length chlorinated paraffin with
70% Cl for 60 days, whole body BCFs of 1158-261 (43% Cl) and 341-223
(70% Cl), respectively, were observed when measured as radioactivity,
and 87.2-1000 (43% Cl) and 105-167 (70% Cl) when based on parent
compound analysis (Madeley & Thompson, 1983c,d). However, the high
doses exceeded the water solubility of the chlorinated paraffins.
4.3.3.4 Comparative studies
The accumulation during four weeks of two 14C-labelled
chlorinated paraffins, polychloro[1-14C]hexadecane (C16;34% Cl,
CP-ML) and 1-chloropolychloro[1-14C]dodecane (C12;69% Cl, CP-SH), was
studied in the mussel (Mytilus edulis) by Renberg et al. (1986).
Both compounds showed rapid uptake when added at concentrations of
0.13 µg/litre (C16;34% Cl) and 0.0029 µg/litre or 0.13 µg/litre
(C12;69% Cl) in water for 28 days. Steady-state levels were reached
within 14 days after exposure to 0.13 µg/litre. The authors
calculated the BCF values to be 6920 for C16;34% Cl and 138 000 for
C12;69% Cl, based on fresh weight. The mussels exposed to C12;69% Cl
were studied for an additional 28 days without exposure. The
elimination rate for this chlorinated paraffin was slow, and 33% of
the radioactivity remained in the tissues after 28 days.
4.3.4 Aquatic plants
The BCF after 10 days exposure to short chain chlorinated
paraffin with 58% chlorination (CP-SH) has been estimated to be 3.5
for the diatom Sceletonema costatum (17.8 µg/litre) and 1.5 for the
green alga Selenastrum capricornutum (35 µg/litre) (Thompson &
Madeley, 1983a,b).
5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1 Environmental levels
Techniques for the analysis of chlorinated paraffin are described
in section 2.3.2. The major problem connected with the analysis of
environmental samples is interference from other compounds. In
earlier studies, when pre-separation techniques were not as well
developed, the concentrations may have been overestimated. Another
problem is that the chlorinated paraffin composition in the
environment may be different from that of the original products,
and the quantitative analysis has to be based on comparisons with
the original products. These difficulties make it clear that
analytical results have to be regarded more as estimates than exact
concentrations.
5.1.1 Air
No information on levels in the atmosphere has been found in the
literature.
5.1.2 Water and sediment
Levels of chlorinated paraffins in water and sediment in the
United Kingdom are summarized in Table 10. Chlorinated paraffins have
been detected in United Kingdom sea water at levels in the range of
0.5-4.0 µg/litre for C10-20 and less than 2.0 µg/litre for C20-30
(Campbell & McConnell, 1980). The levels in sediments from the same
areas were analysed; chlorinated paraffins were detected only in a few
samples at levels up to 500 µg/kg wet weight for C10-20 and 600 µg/kg
for C20-30. The levels of chlorinated paraffins are low in water from
rivers and reservoirs not receiving industrial/domestic effluents
(C10-20, 1 µg/litre or below; C20-30, 2 µg/litre or below) and for
waterways in industrialized regions (C10-20, up to 6.0 µg/litre; C20-30,
0.5 µg/litre or below). The level of C10-20 in the latter regions was
higher than for C20-30. Chlorinated paraffins were not detected in
five drinking-water reservoirs either in the water (detection limit:
0.5 µg/litre) or the sediment (detection limit: 250 µg/kg) (Campbell &
McConnell, 1980). The levels of C10-20 in sediment from non-marine
water remote from industry were in the range up to 1000 µg/kg, except
for a sewage sludge sample from the Liverpool area, which had levels
of 4000-10 000 µg/kg. C20-30 was detected only in one sample at
50 µg/kg. The levels of chlorinated paraffins in sediments close to
industrial plants were found to be higher (C10-20 up to 15 000 µg/kg;
C20-30 up to 3200 µg/kg wet weight). The levels in sediment from these
industrial areas were 1000 times higher than in the overlaying water
columns, indicating the ability of chlorinated paraffins to adsorb on
suspended solids.
Table 10. Levels of chlorinated paraffins in United Kingdom water (µg/litre) and sediment (µg/kg)
(From: Campbell & McConnell, 1980)a
C10-20 C20-30
Range Median No. of samples Range Median No. of samples
level below detection level below detection
limit limit
Sea water
water ND-4.0 0.5 7/15 ND-2.0 ND 13/18
sediment ND-500 ND 14/18 ND-600 ND 15/18
Fresh water remote from industry
water ND-1.0 0.5 7/13 ND-2.0 ND 7/11
sediment ND-1000 ND 4/6 ND-< 250 ND 4/5
Fresh water close to industry
water ND-6.0 1-2 4/25 ND-0.5 ND 8/10
sediment ND-15 000 1800