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T.O. Bd of health supplementary report
CITY OF TORONTO
PUBLIC HEALTH DEPARTMENT
April 26, 1996
To: City Council
Origin: Acting Medical Officer of Health
(p:\1996\ug\hld\cn960047.hld)
Subject: Health and Environmental Considerations Associated with PVC and
Other Pipe Materials Commonly Used by the City of Toronto -
Supplementary Report
Recommendation:
That this report be received for information.
Background:
City Services Committee and the Board of Health held a special joint meeting
on March 25, 1996 to consider the report of the Acting Medical Officer of
Health, "Health and Environmental Considerations Associated with PVC and
Other Pipe Materials Commonly Used by the City of Toronto" (March 19,
1996). This report clarifies and provides additional information on some of
the issues raised in deputations and communications to this joint meeting.
Comments:
The City of Toronto's consideration of a reduction in the use of polyvinyl
chloride (PVC) pipe is one aspect of a world-wide reconsideration of the
manufacture, use or disposal of products which involve or produce
organochlorines and other persistent toxic substances. This reconsideration
has been increasing in recent years as scientists continue to uncover evidence
of damage to the environment, wildlife and humans as a result of the
widespread presence of these substances in the environment.
At the end of World War II, during which time synthetic chemicals played a
pivotal role in the development of military technology, research began in
earnest on the synthesis and use of chemical compounds for a variety of
purposes. Many of these applications, such as new pharmaceutical
compounds, resulted in a significant improvement to human health and the
quality of life.
However, the benefits have not been without costs. Despite early warning
signs, such as research in the early 1960s which documented the adverse
effects of pesticides on song birds, this growth in chemical production and
use continued. Governments in North America and Europe responded to
increasing public concern by introducing legislation and regulations aimed at
controlling the release of persistent toxic substances to the environment.
Most of these actions focussed on the control of pollution discharged into
water, air or onto land. Behind these actions was an assumption that society
could continue to discharge persistent toxic substances to the environment
with little adverse impact and that regulatory decisions about these burdens
could be made on a substance-by-substance basis.
In instances where scientific evidence of harm to the environment, wildlife
species or humans was clear, bans on the manufacture and/or use of a few
specific compounds, such as PCBs, DDT, and lead in gasoline have resulted.
In many cases, by the time a product had been removed from the market,
damage to the environment and human health had already occurred. While
continued releases of these compounds to the environment were halted by
these actions, historical accumulations continued to circulate in the
environment and bioaccumulate in wildlife and humans.
One of the difficulties in regulating the release of toxic chemicals is that
there has traditionally been a significant time lag between the identification of
possible harm and conclusive scientific evidence about the nature and extent
of the harm. This is the nature of scientific investigation; there are very
few substances about which a clear case of cause and effect can be made.
Even the contribution of cigarette smoking to cancer and other diseases, one
of the best documented cases scientifically, is still being debated by some
sectors. While scientific evidence continues to be an important factor in
trying to reduce persistent toxic substances, it is only one of a number of
information sources available to decision-makers. Other factors such as social
and economic considerations also must be weighed. Decision-makers in many
jurisdictions, faced with the weight of scientific evidence about the harm
caused by certain persistent toxic substances, have concluded that it is not
prudent to wait before acting to phase out such compounds.
In the case of organochlorines, there is a growing body of scientific evidence
regarding the harmful impacts of these compounds on wildlife and human
health. While the evidence concerning human health impacts is not as strong,
there is currently sufficient evidence to raise a concern. Rather than
requiring definitive scientific study of every chemical compound before taking
action, there is an opportunity to assume a leadership role and to begin to
move away from the manufacture and use of persistent toxic substances. In
the presence of mounting evidence, many jurisdictions and some corporations
have already taken actions to reduce or remove these compounds from
production and use. This is particularly true when cost effective alternatives
are available or can be developed such as in the case of some PVC products.
The precautionary principle, agreed to at the 1984 World Industry Conference
on Environmental Management, and strengthened in the 1990 United Nations
Economic Commission for Europe Meeting, states that "environmental measures
must anticipate, prevent and attack the causes of environmental degradation"
(International Joint Commission, 1993). The precautionary principle is not
only important for the safety of the environment and human health; it is also
aimed at moving much of our manufacturing capacity to a more sustainable
basis, one that does not involve risk to people manufacturing these
compounds and to the communities that use them. While there may be some
economic dislocation in the short term, some predict that the result will be
additional job creation if the move to non-toxic production is well planned.
World markets are moving slowly but surely in this direction and jurisdictions
that are able to manufacture products without using or producing toxic
substances will ultimately be the ones that benefit both economically and
environmentally. Chemical manufacturers and industries should be encouraged
to experiment with new technology and manufacturing techniques that will
bring about a new era of sustainable production.
The recommendations in my March 19, 1996 report are a measured response to
concerns about the environmental and human health impacts of organochlorines
and the availability of cost effective alternatives to PVC pipe. Chlorine is
used to produce PVC pipe and as a result, organochlorines and other
persistent toxic substances may be formed and released during manufacture
and disposal. City Council has previously recommended that the Department of
Public Health develop a chlorine free strategy and implementation plan which
addresses in particular, construction materials such as PVC products. The
Corporation of the City of Toronto has a tradition of leading by example, of
taking actions as a municipal government that set a course for our citizens
and other levels of government. The Corporation has been a leader in
reducing the purchase and use of toxic substances. Reducing our use of
PVC pipe is another step in this direction.
Comments from Agencies Concerned with Health and Environmental Protection
My previous report (March 19, 1996), included comments on issues related to
the health and environmental impacts of the manufacture, use and disposal of
PVC pipe from agencies concerned with health and environmental protection.
Comments recently received from the Ontario Ministry of Environment and
Energy (MOEE) and the United States Environmental Protection Agency (U.S.
EPA) are integrated into the section below and copies of the letters are
provided in Appendix A.
Certification of PVC pipe by agencies such as the Canadian Standards
Association, Underwriters Laboratories of Canada and Factory Mutual does not
necessarily address the health and environmental aspects of PVC pipe. For
example, the identification of PVC pipe as an "acceptable" material in the
MOEEþs Design Guidelines for Water Mains and Sewers, and the Ministry of
Housing's Plumbing Code is based primarily on operational performance factors
rather than factors related to health or toxicity (Socha, 1996).
The MOEE notes that there are concerns associated with the potential for
release of toxic substances from the manufacture and disposal of PVC but that
there is little evidence to date that suggests any threat to human or
environmental health from the use of PVC pipe (Socha, 1996). At the same
time, the MOEE notes that dibutyltin, a stabilizing agent used in PVC pipe, is
"toxic to humans and exceptionally toxic to wildlife" and is being investigated
for possible estrogenic activity. A pilot study carried out by Health Canada
(Sadiki, Williams, Carrier, & Thomas, 1996) found that low levels of organotin
compounds could leach into drinking water from PVC water supply lines used
in housing projects under three months old. In response to the findings of
this study, Health Canada has initiated a larger-scale pilot study (Socha,
1996).
The U.S. EPA's Office of Solid Waste notes concerns about the release of
dioxins and furans into the environment as unavoidable byproducts of PVC
pipe production (Barron, 1996).
Canadian Environmental Protection Act Priority Substances Lists
The Canadian Environmental Protection Act (CEPA) requires the Ministers of
the Environment and Health to establish Priority Substances Lists (PSL) which
identify substances to be assessed to determine whether they are `toxic'.
Two Lists (PSL1, PSL2) have been established. A substance also may be
placed on Schedule 1 of CEPA and subject to control without an assessment
under the PSL process if the Ministers are satisfied that the substance is
`toxic' under CEPA (Ministers' Expert Panel on the PSL2, 1995).
At least three substances which are used in the manufacture of PVC pipe or
which may result from its manufacture or disposal have been defined as toxic
under CEPA:
- Vinyl chloride monomer (a constituent of PVC),
- 1, 2-Dichloroethane also known as ethylene dichloride (a constituent of
PVC),
- Dioxins and furans (potential by-products of the manufacture and
disposal of PVC-containing products).
Substances which are defined as `toxic' under CEPA may be subject to
management options such as guidelines, codes of practice or regulations.
Vinyl chloride releases are managed under the Vinyl Chloride Release
Regulations and the Code of Good Operating Practice for Vinyl Chloride and
Polyvinyl Chloride Manufacturing Operations. The Release Regulations
establish limits for emissions of vinyl chloride. The Code of Practice outlines
control strategies to minimize fugitive (i.e., non-point source) emissions from
manufacturing operations.
Management of ethylene dichloride is currently being investigated. Work for
a background document which is expected to be released by the summer of
1996, will involve the identification of sectors in which ethylene dichloride is
used, and whether improvements are necessary for the management of
ethylene dichloride (personal communication, Francine LaPierriere,
Environment Canada, April 1996). Management strategies for dioxins and
furans are outlined in the following section.
Organotin compounds are used as heat stabilizers in PVC pipe. A recent
assessment conducted under CEPA concluded that available data are
insufficient to assess whether these compounds are `toxic' as defined under
CEPA (Government of Canada, Environment Canada, and Health and Welfare
Canada, 1993).
Releases from the manufacture, combustion and disposal of PVC plastics were
nominated but not recommended for the PSL2. The Ministers' Expert Panel on
the PSL2 (1995) was unable to reach consensus on whether these substances
should be subject to an assessment under CEPA. The Panel expected that
the Memorandum of Understanding that is being negotiated among Environment
Canada, Industry Canada and the Canadian vinyl industry would ensure
appropriate assessment and management of these substances. Nevertheless,
the Panel (1995) expressed the following concerns about potential releases
from PVC as well as the Memorandum of Understanding.
Health and environmental risks can result from the formation of
certain chlorinated compounds including dioxins and furans and
hydrochloric acid during combustion; the release of certain toxic,
chlorinated substances, monomers and plasticizers during
manufacture, and degradation of products during their use and in
landfills after their disposal....The Panel expressed concerns that
activities under the Memorandum might not lead to progress
comparable to that enabled by an assessment under CEPA and
with the lack of public participation to date and opportunity for
oversight afforded by the Memorandum. In light of these
uncertainties, and the concerns mentioned above, some members
of the Panel thought it of critical importance to recommend these
substances for PSL2 or recommend that the Ministers ensure that
the Memorandum address these concerns. Others felt that
assessment of these substances under CEPA could divert scarce
assessment resources without achieving more than the Memorandum
being negotiated.
When the Memorandum of Understanding has been completed, I will report on
its content and implications.
Dioxins and Furans
A number of issues concerning dioxins and furans were raised by deputants
at the March 25, 1996 meeting of City Services Committee and the Board of
Health. These include: the vinyl industry's activities to characterize dioxin
emissions and the potential formation of dioxins and furans from the
incineration of waste materials containing PVC. The following sections
provide additional information in order to clarify some points made during the
deputations.
Dioxins and furans are found in air, water, soil, sediments, animals and
foods (Government of Canada, Environment Canada, Health and Welfare
Canada, 1993). While some dioxins are produced naturally, historical
deposition records suggest that human activity is the main source of dioxins
(Thomas and Spiro, 1996). The formation of dioxins and furans is closely
correlated with the production of chlorinated compounds (U.S. EPA Science
Advisory Board, 1995). Dioxins are inadvertently produced through activities
such as combustion, certain types of chemical manufacturing, chlorinated
bleaching of pulp and paper and other industrial processes (United States
Environmental Protection Agency, 1994).
As indicated above, dioxins and furans have been defined as `toxic' under
CEPA. Humans are principally exposed to dioxins through diet (U.S. EPA
Science Advisory Board, 1995). The U.S. EPA's draft dioxin reassessment
reaffirms the link between dioxin and cancer and concludes that dioxin
exposure at some level may result in a number of non-cancer health effects in
humans (United States Environmental Protection Agency, 1994). When
completed, the reassessment will serve as the scientific basis for additional
dioxin policy and program development in the United States (United States
Environmental Protection Agency, 1994).
At this time, Environment Canada has few management strategies which
specifically target dioxins and furans. The following specific initiatives are
in effect or under way:
- Federal Pulp and Paper Effluent Regulations were promulgated under
the Canadian Environmental Protection Act in 1992 to address
chlorinated dioxin and furan releases in pulp and paper mill effluent
from mills using a chlorine bleaching process (Environment Canada,
1995).
- A federal-provincial Task Force has been established to identify and
characterize anthropogenic sources of dioxins and furans and prepare
action plans. The Task Force is addressing the PVC industry as part of
its work (personal communication, Raouf Morcos, Environment Canada,
April 1996.)
Vinyl Industry Activities to Characterize Dioxin Emissions
Vinyl industry literature indicates that sampling programs are being carried
out to characterize aspects of the vinyl industry's contribution to dioxin
emissions. Based on preliminary results of these sampling programs, the
vinyl industry has drawn a number of conclusions, some of which are
summarized below. At this time, it is not possible to comment on the validity
of these conclusions. As with any scientific study, the methods and results
of sampling programs would need to be peer reviewed before the conclusions
of the study could be validated.
According to a fact sheet from The Vinyl Institute (December, 1995), the
U.S. EPA draft dioxin reassessment does not identify vinyl products as a
potential source of dioxins. However, the vinyl industry anticipated that it
would be examined because of vinyl's dependence on chlorine. As a result,
the vinyl industry has undertaken a multi-year characterization program
based on U.S. EPA protocols to measure potential dioxin emissions from
representative points in the vinyl production process. Results of these tests
are being shared with the U.S. EPA as they become available. Testing is
expected to be completed by the end of 1997.
According to The Vinyl Institute fact sheet, the first phase of testing
included:
- pipe, packaging, bottle and dispersion resin products,
- water discharges from on-site waste treatment plants,
- ethylene dichloride,
- þbiosludgeþ resulting from on-site waste treatment plants,
- air (stack) emissions from on-site incinerators.
On the basis of limited preliminary test results, the vinyl industry has drawn
the following conclusions with respect to the constituents of PVC pipe and the
vinyl industry in general:
- no measurable amounts of dioxin at the parts per trillion level in 12
different samples of PVC pipe resin provided by six different
manufacturers (The Vinyl Institute, 1995),
- measurements of dioxins under 2 parts per trillion in roughly half of
the samples and non-detectable levels in the remainder from ethylene
dichloride (one of the substances used to manufacture vinyl) (The Vinyl
Institute, 1995),
- an upper limit of annual dioxin emissions from the U.S. vinyl industry
of less than 5 grams as indicated by samples of plant effluent water,
resin and other products (Krause, 1996),
- an estimated 0.4 grams of dioxins per year to water from the U.S.
vinyl industry's on-site waste treatment plants (The Vinyl Institute,
1995),
- minor contributions to dioxin levels from the vinyl industry in Europe
(The Vinyl Institute, 1995).
Incineration of Waste Materials Containing PVC
PVC-containing products are likely to be incinerated in municipal solid waste
and medical waste incinerators. Concerns have been raised about the
potential formation of dioxins and furans from the incineration of these
products. According to Environment Canada, all solid waste incinerators
contribute to the release of dioxins (personal communication, Raouf Morcos,
Environment Canada, April 24, 1996). However, incinerators that are well
run (controlled) release fewer dioxins than those that are not well operated
(personal communication, Raouf Morcos, Environment Canada, April 24, 1996).
As indicated in my March 19, 1996 report, incomplete combustion of PVC-
containing products can result in the formation of dioxin. The relationship
between chlorine concentrations in the waste feed of municipal and medical
waste incinerators and dioxin emissions are still being studied and debated.
One report prepared for Environment Canada (Rigo, Chandler, and Lanier,
1995) reviewed available data from a number of testing programs which are
designed to determine factors influencing dioxin and furan emissions to assess
if PVC separation is likely to produce measurable reductions in dioxin and
furan emissions from incinerators. One limitation of the report was that it did
not explain the type of criteria used to include or exclude the testing
programs. The study concluded that there is no consistent relationship
between dioxin and furan emissions and chlorine concentrations in the waste
feed because any changes induced by PVC or other chlorine sources were
found to be smaller than the experimental error or the variations induced by
other operational effects and design parameters. However, the study did
note that dioxin and furan concentrations were consistently elevated in
situations involving poor combustion conditions.
David McKeown, MDCM, MHSc, FRCPC, FACPM
Acting Medical Officer of Health
References
Ministers' Expert Advisory Panel on the PSL2. (October 1995). Report of the
Ministers' Expert Advisory Panel on the second Priority Substances List
Under the Canadian Environmental Protection Act (CEPA).
Acting Medical Officer of Health. (March 19, 1996). Health and Environmental
Considerations Associated with PVC and Other Pipe Materials Commonly Used
by the City of Toronto - Overview Report. Report to Board of Health and
City Services Committee.
Barron, M.A. (March 12, 1996). United States Environmental Protection
Agency, Office of Solid Waste. Letter.
Environment Canada. (October 1995). Chlorinated Substances Action Plan
Progress Report.
Government of Canada. Environment Canada. Health Canada. (1994). Canadian
Environmental Protection Act Priority Substances List Assessment Report 1,2-
Dichloroethane.
Government of Canada. Environment Canada. Health and Welfare Canada.
(1993). Canadian Environmental Protection Act Priority Substances List
Assessment Report No. 1 Polychlorinated Dibenzodioxins and Polychlorinated
Dibenzofurans.
Government of Canada. Environment Canada. Health and Welfare Canada.
(1993). Canadian Environmental Protection Act Priority Substances List
Assessment Report Non-pesticidal Organotin Compounds.
Hall, R.H. (August 1988). Report of the Ministers' Priority Substances
Advisory Panel Under the Canadian Environmental Protection Act.
International Joint Commission. (August 1993). A Strategy for Virtual
Elimination of Persistent Toxic Substances. Volume 1. Report of the Virtual
Elimination Task Force to the International Joint Commission.
Krause, F.E. (March 25, 1996). The Geon Company. Deputation before the
City of Toronto City Services Committee and the Board of Health.
LaPierriere, F. (April 1996). Environment Canada. Personal Communication.
Morcos, R. (April 1996). Environment Canada. Personal Communication.
Rigo, H.G., Chandler, A.J., and Lanier, W.S. (1995). The Relationship
Between Chlorine in Waste Streams and Dioxin Emissions from Waste Combustor
Stacks. An ASME Research Report. New York, NY: The American Society of
Mechanical Engineers.
Sadiki, A-I., Williams, D.T., Carrier, R., and Thomas, B. (1996). "Pilot
study on the contamination of drinking water by organotin compounds from
PVC materials". Accepted for
publication in Chemosphere.
Socha, A. (April 16, 1996). Ontario Ministry of Environment and Energy,
Regulatory Toxicology, Environmental Standards Section. Letter.
Thomas, V.M., and Spiro, T.G. (1996). "The U.S. dioxin inventory: Are
there missing sources?". Environmental Science & Technology/News 30(2),
82A-85A.
United States Environmental Protection Agency. (September 13, 1994). EPA
Calls for New Dioxin Data to Complete Reassessment Process. Press Release.
United States Environmental Protection Agency Science Advisory Board. (May
15-16, 1995). Dioxin Reassessment Review.
United States Environmental Protection Agency. (September 29, 1995). Science
Advisory Board Approves Dioxin Review. Press Release.
The Vinyl Institute. (December 1995). The Vinyl Industry's Dioxin Testing
Program: Background and Status Report. Fact Sheet.
APPENDIX A
April 16, 1996
Ms. Siu Fong
Environmental Protection Office,
Public Health Department,
City of Toronto
City Hall, 100 Queen St. West,
Toronto, ON M5H 2N2
Dear Ms. Fong:
This is in response to Dr. McKeown's letter of March 26th to Ms. Ivy Wile
and to your telephone call to me of April 11th, seeking information about the
potential environmental and human health effects of polyvinyl chloride (PVC)
potable water pipes and sewer pipes.
PVC is listed as an acceptable pipe material in the Ministry of Environment
and Energy's Design Guidelines for Water Mains and Sewers, as well as in the
Ministry of Housing's Plumbing Code. Note however that in both instances,
the determination of materials as "acceptable" depends primarily on operational
performance factors including structural and dimensional integrity, such as
pipes not cracking and keeping their shape, rather than factors related to
health or toxicity.
Although concerns exist regarding the potential for release of toxic
substances when PVC is made and when it is disposed of by incineration,
there has been little evidence to date that PVC pipes present any threat to
human or environmental health while in use. Notwithstanding this, a small
pilot study conducted last year by Health Canada revealed that a small amount
of dibutyltin, a stabilizing agent added to PVC, does appear to leach out of
PVC water supply pipes used in housing projects under three months old.
The pilot study was inconclusive as to the relevance of the dibutyltin leaching
to human health; the levels leached out were low, and no leaching from the
pipes occurred after three months. Furthermore, the degree of leaching
depends on the pH and hardness of the water flowing through the pipes.
Dibutyltin and other organotin compounds are toxic to humans and are
exceptionally toxic to aquatic life. These compounds are also being
investigated as to their possible estrogenic activity. In light of this, the
Federal-Provincial Drinking Water Subcommittee has indicated that there may
be drinking water-related health concerns regarding PVC pipe that have not
been fully addressed. In response, Health Canada has initiated a larger-scale
pilot study of this matter involving water sampling in three provinces and
including five municipalities in Ontario (Ottawa-Carleton, Barrie, Guelph,
Whitby and London).
The results of Health Canada's PVC pipe/drinking water study will be used to
assess the potential health hazard of organotin compounds in drinking water.
Also, because organotin compounds were included on the first Canadian
Environmental Protection Act (CEPA) Priority Substances List, Health Canada
will concurrently investigate the extent of human exposure to dibutyltin to
determine if the substance constitutes an existing danger to human life or
health in Canada. Environment Canada may do the same from an
environmental perspective.
Health Canada has the lead role on this issue and as such we will await their
advice at the conclusion of their study. They are keeping this Ministry
apprised of developments in their PVC pipe/drinking water investigation
through our Branch's representative on the Federal-Provincial Drinking Water
Subcommittee. You may wish to contact us again in six months or so for any
new information, or alternatively you may wish to contact Ms. Michele
Giddings at Health Canada, (613) 952-2594.
Sincerely,
Original Signed By
Adam C. Socha
Senior Advisor, Regulatory Toxicology
Environmental Standards Section
cc. I. Wile
J.J. Smith
G. Jenkins
March 12, 1996
Ms. Siu Fong
City of Toronto Environmental Protection Office
100 Queen Street West
64 East Tower
Toronto, Ontario
CANADA M5H 2N2
Dear Ms Fong:
Thank you for responding to my letter requesting more information about the
City of Toronto's interest in potentially phasing out the use of PVC pipe. I
received a letter with enclosures from Dr. David McKeown of your City. I am
also aware of the concern by certain parties about the release of dioxin and
PCBs into the environment as unavoidable byproducts of polyvinyl chloride
pipe production.
As I promised, I have discussed this concern with EPA staff of the Office of
Solid Waste staff and have also researched our files. Unfortunately, this
search did not result in any materials to send you, as this Office has not
prepared any position papers on this subject. You are much more likely to
obtain the information you need from EPA's Office of Water, as this issue has
been a concern within that Office. You have my best wishes for preparation
of your report.
Yours very truly,
Original Signed By
Monica A. Barron, Ph.D., Toxicologist
Economics, Methods and Risk Assessment Division (5307)
Office of Solid Waste