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- Listed on the First Priority Substances List (PSL1)
- Follow-up Assessment Conducted to Include New Information
- Draft report being revised following public comment period
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Chlorinated paraffins (CPs) were one of the 44 substances or groups of substances
placed on the First
Priority Substances List (PSL1) to determine whether they posed a
risk to the health of Canadians or to the environment.
The final PSL1 assessment report was published in 1993 and concluded
that short chain CPs were toxic to human health. However, there was insufficient
information to conclude whether short, medium or long chain CPs were harmful
to the environment or whether medium or long chain CPs were considered
a danger to human health.
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Assessment Status and Conclusion
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Environment Canada and Health Canada have completed draft scientific assessments
of short chain, medium chain, and long chain CPs, as a follow-up to the
PSL1 assessment.
The Draft Follow-up Reports are currently
available for public comment (June
11, 2005 - August 10, 2005).
The Draft Follow-up Report prepared by Environment Canada proposes that
short, medium, and certain long chain CPs are toxic to the environment,
as defined under Canadian Environmental Protection Act, 1999
(CEPA 1999), and would be proposed as candidates for virtual
elimination.
The Draft Follow-up Report prepared by Health Canada confirms the conclusion
that short chain CPs are toxic to human health and proposes that medium
and long chain CPs are suspected to be toxic to human health.
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- A Notice and the proposed measure have been published in the Canada
Gazette Part I on June 11, 2005.
- Synopsis of Draft Follow-up Report for the Environment
(2004)
HTML
and PDF
- Synopsis of Draft Follow-up Report for Human Health
(2004)
HTML
and PDF
- Synopsis of PSL1 Assessment Report (1993)
HTML
and PDF
- Draft PSL1 Follow-up Report on Chlorinated Paraffins. Government of Canada,
Environment Canada (2004)
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To obtain an electronic copy of the report, please send an email
to ESB.DSE@ec.gc.ca,
or to obtain a paper copy of Environment Canada's
Follow-up Report, please contact us at:
Existing Substances Division Environment Canada 20th Floor, Place Vincent Massey 351 St. Joseph Blvd. Gatineau, Québec K1A 0H3 Phone: (819) 997-0822 Fax: (819) 953-4936
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- Draft PSL1 Follow-up Report on Chlorinated Paraffins. Government of Canada,
Health Canada (2004)
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To obtain a paper copy of the report, please contact the Inquiry Centre of Environment Canada at:
Inquiry Centre 70 Crémazie, 7th Floor Gatineau, Québec K1A 0H3 Phone: 1-800-668-6767
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Synopsis of PSL1 Assessment
Report (1993)
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The term "chlorinated paraffin waxes" is generally restricted
to chlorinated paraffins having long carbon chains (i.e., >=C18).
However, the scope of this assessment was broadened to include the short
chain (i.e., <=C13) and medium chain (i.e., C14-17) chlorinated paraffins
which are also of concern because of their potential effects on the
environment and human health.
Chlorinated paraffins (CPs) are produced in, and imported into, Canada
for use as plasticizers and flame retardants as well as extreme-pressure
additives in lubricating oils. They are persistent compounds and have
the potential to bioaccumulate in aquatic organisms. No data were identified
on the concentrations of these substances in any medium in the Canadian
environment. However, data from other countries (including the United
States) where these compounds are produced and used confirm their presence
in the environment, particularly near production facilities.
Short chain chlorinated paraffins cause adverse effects in fish and
aquatic invertebrates at concentrations below 1 µg/L in laboratory
studies. However, owing to the lack of information on concentrations
of short chain chlorinated paraffins in the Canadian environment, it
is not possible to estimate exposure of Canadian biota or to compare
this exposure with levels estimated to cause adverse effects.
Short chain chlorinated paraffins have caused cancer in experimental
animals, although relevant data for humans are not available. Therefore,
short chain chlorinated paraffins are considered to be "non-threshold
toxicants", i.e., substances for which there is believed to be
some chance of adverse effects at any level of exposure. For such substances,
where data permit, estimated exposure is compared to quantitative estimates
of cancer potency in order to characterize risk and provide guidance
for further action, such as analysis of options to reduce exposure,
under the Canadian Environmental Protection Act (CEPA). However, owing
to the lack of information on concentrations of short chain chlorinated
paraffins in environmental media to which humans are exposed, it is
not possible to quantitatively estimate the total average daily intake
of these compounds by the general population in Canada, or to subsequently
compare these values to quantitative estimates of cancer potency.
There is also a lack of information on concentrations of medium and
long chain chlorinated paraffins in environmental media to which humans
and other biota are exposed. Therefore, it is not possible to estimate
exposure of Canadian biota or to compare this exposure with levels estimated
to cause adverse effects. Similarly, it is not possible to quantitatively
estimate the total average daily intake of these compounds by the general
population in Canada. The Tolerable Daily Intakes (i.e., the intake
to which it is believed that a person can be exposed over a lifetime
without deleterious effect) are derived on the basis of data from bioassays
in animal species for these two groups of chlorinated paraffins and
therefore cannot be compared with the estimated total daily intake in
the general environment in Canada.
None of the chlorinated paraffins volatilizes readily to the
atmosphere. Due to their predicted short tropospheric residence time
(a few days), these compounds are not expected to contribute significantly
to depletion of stratospheric ozone or global warming. Based on these
considerations, the Minister of the Environment and the Minister of
National Health and Welfare have concluded that short chain chlorinated
paraffins are considered to be "toxic" as defined under Paragraph
11(c) of the Canadian Environmental Protection Act. Available data are
considered inadequate to evaluate whether medium and long chain chlorinated
paraffins are considered to be "toxic" as defined under Paragraphs
11(a) or (c) of the Canadian Environmental Protection Act.
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Synopsis of Draft Follow-up Report for the Environment (2004)
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Chlorinated paraffins (CPs) are chlorinated derivatives of n-alkanes,
having carbon chain lengths ranging from 10 to 38 and a chlorine content
ranging from 30 to 70% by weight. CPs, include short chain chlorinated
paraffins (SCCPs) (CPs with 10–13 carbon atoms), medium chain
chlorinated paraffins (MCCPs) (CPs with 14–17 carbon atoms) and
long chain chlorinated paraffins (LCCPs) (CPs with >=18 carbon atoms).
CPs that appeared on the first Priority Substances List (PSL1) were
assessed to determine whether they should be considered “toxic”
as defined under the Canadian Environmental Protection Act (CEPA). With
the data available at that time, it was concluded in the PSL1 assessment
that SCCPs were “toxic” because they were constituting or
may constitute a danger in Canada to human life or health under paragraph
11(c) of CEPA 1988; however, there was insufficient information to conclude
whether SCCPs, MCCPs or LCCPs could have immediate or long-term harmful
effects on the environment under paragraph 11(a) or whether MCCPs or
LCCPS could be considered “toxic” under paragraph 11(c).
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Subsequent to the completion of the PSL1 assessments, a revised CEPA,
CEPA 1999, came into effect. Paragraph 64(a) of CEPA 1999 has a definition
of “toxic” that is similar to that in paragraph 11(a) under
the original CEPA, and addresses whether a substance has or may have
an immediate or long-term harmful effect on the environment. However,
in CEPA 1999 paragraph 64(a) has been expanded to include effects on
biodiversity. Research to address data gaps relevant to the assessment
of impacts on the environment was funded. Recent literature was reviewed
for new data on concentrations in the environment, as well as for information
on the effects on human and non-human organisms.
Total reported annual usage of CPs in Canada (production + imports
– exports) was approximately 3000 tonnes in 2000 and 2001. MCCPs
accounted for a large majority of CP usage in Canada, followed by smaller
proportions of SCCPs and LCCPs. The major uses of CPs in Canada are
in plastics, in lubricating additives and in metalworking. There is
only one manufacturer of CPs in Canada, and only MCCPs and LCCPs are
produced at this facility. In 2000, their production capacity was reported
to be 8.5 kilotonnes.
There are no known natural sources of CPs. The major sources of release
of CPs into the Canadian environment are likely the formulation and
manufacturing of products containing CPs, such as polyvinyl chloride
(PVC) plastics, and use in metalworking fluids. The possible sources
of releases to water from manufacturing include spills, facility wash-down
and drum rinsing/disposal. CPs in metalworking/metal cutting fluids
may also be released to aquatic environments from drum disposal, carry-off
and spent bath. These releases are collected in sewer systems and often
ultimately end up in the effluents of sewage treatment plants. When
released to the environment, CPs tend to partition primarily to sediment
or soil.
In this assessment, the LCCPs were divided into two groups: (1) C18–20
and C>20 liquid LCCPs (together referred to as liquid LCCPs) and
(2) C>20 solid LCCPs. This division was made based on their different
physical/chemical properties, which are related to the much higher chlorine
content of C>20 solid LCCPs relative to liquid LCCPs.
SCCPs have been detected in the following environmental samples from
Canada: in Arctic air, in sediments from remote northern lakes, in sewage
treatment plant effluents from southern Ontario, in surface water, sediments
and fish from Lake Ontario and in marine mammals from the Canadian Arctic
and the St. Lawrence River. MCCPs have been detected in effluent from
a CPs manufacturing facility near Cornwall, Ontario, and also in sediments
near this facility, in fish from Lake Ontario and in beluga from the
St. Lawrence River. Internationally, MCCPs have been detected in sewage
sludge, surface water near a CPs manufacturing plant, sediments, fish,
aquatic invertebrates and earthworms. Maximum Canadian concentrations
of SCCPs and MCCPs were observed in aquatic biota and sediments from
the St. Lawrence River and also in sediments and fish from southwestern
Ontario. No data on environmental concentrations in Canada exist for
LCCPs. They have been detected in marine sediments, crabs and mussels
near a CPs manufacturing facility in Australia.
Atmospheric half-lives for many CPs are estimated to be greater than
2 days. In addition, SCCPs have been detected in Arctic biota and lake
sediments in the absence of significant sources of SCCPs in this region,
which suggests that long-range atmospheric transport of SCCPs is occurring.
SCCP and MCCP residues have been detected in Canadian lake sediments
dating back over 25 years, suggesting that the half-lives of SCCPs and
MCCPs in sediment are greater than 1 year. There are no data available
for LCCPs in Canadian lake sediments; however, based on their physical/chemical
properties, which are similar to those of MCCPs, LCCPs are expected
to be persistent in sediments. It is therefore concluded that SCCPs,
MCCPs and LCCPs are persistent as defined in the Persistence and Bioaccumulation
Regulations of CEPA 1999.
Bioaccumulation factors (BAFs) of 16 440–25 650 wet weight (wet
wt.) in trout from Lake Ontario indicate that SCCPs are bioaccumulating
to a high degree in aquatic biota in Canada. This is supported by very
high bioconcentration factors (BCFs) for SCCPs measured in mussels (5785–138
000 wet wt.). Despite the lack of valid laboratory studies of BCFs and
BAFs, MCCPs and liquid LCCPs have been found to have significant potential
to bioaccumulate in aquatic food webs: field BAFs for MCCPs in Lake
Ontario fish are estimated to range from 7.77 × 105 to 5.45 ×
106 wet wt.
Furthermore, MCCPs were found to have biomagnification factors (BMFs)
greater than 1 in the Lake Ontario food web and in laboratory studies
with rainbow trout and oligochaetes. The LCCP C18H30Cl7 had BMF values
greater than 1 in rainbow trout in laboratory studies, and its half-life
in rainbow trout was found to be similar to those of recalcitrant compounds
that are known to accumulate in organisms and magnify in food chains.
In addition, MCCPs and LCCPs have octanol–water partition coefficient
(log KOW) values greater than 7, elevated concentrations of MCCPs have
been measured in aquatic biota from the St. Lawrence estuary, the United
States and Australia, and elevated concentrations of LCCPs have been
found in marine benthic organisms in Australia. Therefore, based on
these data, as well as the physical/chemical similarities of CP chain
lengths, it is concluded that SCCPs, MCCPs and liquid LCCPs meet the
bioaccumulation criteria as defined in the Persistence and Bioaccumulation
Regulations of CEPA 1999.
In cases where appropriate Canadian environmental exposure data were
not available, international concentration data were used for the risk
quotients. Conservative risk quotients indicate that SCCPs, MCCPs and
liquid LCCPs have the potential to harm pelagic and soil organisms,
that SCCPs and MCCPs may harm benthic organisms and that SCCPs have
the potential to harm fish-eating wildlife through food chain effects.
Based on the limited toxicity data available and the use of environmental
exposure data for liquid LCCPs, C>20 solid LCCPs appear to have low
potential to harm Canadian wildlife through food chain effects. However,
no toxicity studies for C>20 solid LCCPs were available with daphnids,
which was the most sensitive organism for SCCPs, MCCPs and liquid LCCPs.
As CPs have been found to persist in the environment and to have the
potential to bioaccumulate, risk assessments for these compounds were
more conservative than for compounds not meeting the criteria defined
in the Persistence and Bioaccumulation Regulations of CEPA 1999.
There are special concerns about persistent and bioaccumulative substances.
Persistent substances can remain in the environment for long periods
of time, increasing the probability and the duration of exposure. In
addition, the long-range atmospheric transport of persistent substances
may result in low-level, widespread contamination. Bioaccumulative substances
have the potential to biomagnify; consequently, releases of extremely
low concentrations of persistent and bioaccumulative substances may
— either alone or in combination with similar substances —
cause severe adverse effects.
Based on the information available, it is proposed that SCCPs, MCCPs
and C18–20 and C>20 liquid LCCPs are entering the environment
in quantities or concentrations or under conditions that have or may
have an immediate or long-term harmful effect on the environment or
its biological diversity. Therefore, it is proposed that SCCPs, MCCPs
and C18–20 and C>20 liquid LCCPs be considered “toxic”
as defined in paragraph 64(a) of CEPA 1999. SCCPs, MCCPs and C18–20
and C>20 liquid LCCPs are persistent, bioaccumulative and predominantly
anthropogenic and thus they also meet the criteria for Track 1 substances
under the Government of Canada Toxic Substances Management Policy, making
them candidates for virtual elimination.
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Synopsis of Draft Follow-up Report for Human Health (2004)
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Short-chain chlorinated paraffins (SCCP) are imported into Canada
for use as additives in extreme-pressure lubricants, plasticizers and
flame retardants. Medium- and long-chain chlorinated paraffins (MCCP
and LCCP, respectively) are produced in, and imported into, Canada for
similar uses.
Chlorinated paraffins were included on the first Priority Substances
List (PSL1) under the 1988 Canadian Environmental Protection Act (CEPA
1988) for assessment of potential risks to the environment and human
health. As outlined in the Assessment Report released in 1993, relevant
data identified before August 1992 were considered insufficient to conclude
whether MCCP and LCCP were “toxic” to human health as defined
in Paragraph 11(c) of CEPA 1988. As also outlined in the Assessment
Report released in 1993, SCCP were considered to be “toxic”
as defined under Paragraph 11(c) of CEPA 1998. This conclusion was based
principally on the observed carcinogenicity of these compounds, for
which available information on mode of action could not preclude it
being the result of direct interaction with genetic material. To set
context for the update on MCCP and LCCP, more recent data on the effects
of SCCP on human health have also been considered here, and the conclusion
under Paragraph 11(a) of CEPA 1988 has been updated.
For SCCP, critical data relevant to both estimation of exposure of
the general population in Canada and assessment of the weight of evidence
for the mode of induction of specific tumours were identified following
release of the PSL1 assessment and prior to February 2001, although
most of this information has been reported in incomplete published summary
accounts or abstracts. These data suggest that several tumours observed
in carcinogenicity bioassays in rats and mice exposed to SCCP are induced
by modes of action either not relevant to humans (kidney tumours in
male rats) or for which humans are likely less sensitive (in rats, liver
tumours related to peroxisome proliferation and thyroid tumours related
to thyroid–pituitary disruption). Additional documentation of
available studies and consideration in additional investigations of
the reversibility of precursor lesions in the absence of continued exposure
is desirable. However, reported data on mode of induction of tumours
in addition to the weight of evidence that SCCP are not DNA reactive
are at least sufficient as a basis for consideration of a Tolerable
Daily Intake (TDI) for non-cancer effects as protective for carcinogenicity
for observed tumours.
Upper-bounding estimates of daily intake of SCCP approach or exceed
the TDI for these compounds, which, on the basis of available information,
is likely also protective for carcinogenicity.
Therefore, the Ministers of the Environment and of Health confirm
that short-chain chlorinated paraffins are “toxic” to human
health as defined in Paragraph 64(c) of the Canadian Environmental Protection
Act, 1999 (CEPA 1999).
For MCCP and LCCP, critical data relevant to both estimation of exposure
of the general population in Canada and assessment of effects were identified
following release of the PSL1 assessment and prior to December 2000.
Based upon these semi-quantitative data, upper-bounding estimates of
daily intake for MCCP and LCCP are within the same order of magnitude
of, or exceed, the TDIs for these compounds.
Therefore, it is proposed that there is reason to suspect that
medium- and long-chain chlorinated paraffins are “toxic”
to human health as defined in Paragraph 64(c) of the Canadian Environmental
Protection Act, 1999 (CEPA 1999).
Acquisition of data on levels of these compounds (SCCP, MCCP and LCCP)
within foodstuffs in Canada continues to be considered a high priority.
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