Science assessment review

Ronald W. Brecher, PhD, DABT, C.Chem.
5515 Wellington Rd. 39, Guelph, ON N1H 6J2
T: (226) 979-6664 E: rbrecher@rogers.com

November 16, 2020

Mr. Stan Rodriguez
VP, Regulatory Affairs,
Vinyl Institute of Canada
Suite 3, 1425 North Service Rd. E.
Oakville, ON L6H 1A7

By email

Dear Mr. Rodriguez:

Re: Technical Review of Selected References in “Science Assessment of Plastic Pollution”: Focus on Vinyl

Introduction

The Vinyl Institute of Canada (VIC) is preparing comments on the Government of Canada’s proposal to classify “plastic manufactured items” as “toxic” under Section 64 of the Canadian Environmental Protection Act (CEPA). It is likely that this proposal is based in part on the recently completed Science Assessment of plastic pollution (Government of Canada, 2020, referred to as “the Science Assessment”). The Science Assessment includes the conclusion that “In keeping with the precautionary principle, action is needed to reduce macroplastics and microplastics that end up in the environment.” There are no recommendations specific to vinyl (also referred to as PVC in this report).

The VIC contracted the undersigned to review selected documents cited in the Science Assessment and comment on them from the perspective of whether they support a classification of vinyl as “toxic” under CEPA, including an examination of whether the application of the precautionary principle to vinyl is supported by the information reviewed.

Background

In October 2020, the Government of Canada proposed adding “plastic manufactured items” to the Schedule I list substances classified as “toxic” under the Canadian Environmental Protection Act, 1999 (CEPA). Section 64 sets out the criteria for considering a substance toxic:

“Substances are considered harmful if they are entering or could enter the environment in quantities or concentrations or under conditions that: have or may have

Among other things, adding a substance to Schedule I of CEPA permits the substance to be regulated, with management measures to mitigate an adverse effect.

Designation of “plastic manufactured items” as “toxic” under CEPA would pave the way for Canada to implement proposed measures to ban a variety of plastic items by 2021 (ECCC, 2019).

Interestingly, polyvinyl chloride (PVC; vinyl) is the only plastic identified by name in ECCC (2019). None of the non-PVC plastics that make up most of the articles proposed to be banned are identified within the document.

Approach

Much of the literature cited in the Science Assessment is either specific to other (non-PVC) plastics, or about plastics as a group. For the current review, the VIC identified 16 papers cited in the draft Science Assessment that specifically consider PVC. The papers selected by the VIC focused mainly on adverse effects of microplastics. Three additional references were reviewed to gain a high-level view of the of the prevalence of PVC in marine plastic pollution. Each paper was considered in the context of whether it supported a conclusion that vinyl is “toxic” under the CEPA Section 64 definition.

Attachment A contains brief summaries of the 19 papers reviewed, highlighting their relevance to assessing risks related to vinyl. For each paper, a conclusion is provided of whether the information supports a determine of “toxic” under CEPA.

The Science Assessment concluded that action be taken based on the precautionary principle. Therefore, this report also discusses whether the information reviewed supports the conclusion that the precautionary principle should be applied to vinyl.

Throughout this document, citations correspond to those in the Science Assessment.

Findings

None of the references reviewed support a conclusion that vinyl is “toxic” under the CEPA Section 64 definitions, at least in the chemical toxicity sense (entanglement is discussed below). While some laboratory studies report adverse effects following exposure to PVC in various species, these tended to use high doses, limiting their relevance. Some of the studies reviewed used more realistic exposure levels and did not observe adverse effects. The human evidence is also equivocal. For example, Prata (2018), which tabulated occupational exposure studies, did not differentiate between exposures to vinyl chloride and PVC, confounding the assessment of PVC’s contribution to the observed outcomes.

There is some evidence that vinyl may represent a relatively minor component of plastic pollution. Neither Horm et al. (2019) or Zhou et al. (2018) mention vinyl particles in samples taken from thousands of kilometers of beaches in California and China, respectively. Further, de Haan (2019) found little PVC in floating plastic pollution; PVC was grouped with several other minor components that together accounted for 5.5% of the total.

The studies selected by the VIC for this review did not address the issue of entanglement, so this report cannot comment on the possible role of PVC in this phenomenon.

Precautionary principle context

The precautionary principle as stated in CEPA is as follows:

“Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”

This risk management principle describes how Canada makes decisions in the face of scientific uncertainty. Essentially it can be distilled to the notion of “erring on the side of caution.” However, the statement does not define or prescribe what is considered “serious or irreversible damage”, or how “cost effectiveness” should be measured.

CEPA Section 64 provides some guidance on the first point. In essence, whether a substance is harmful depends on how much and where it is entering the environment, and whether it could cause adverse effects in that context. While the Science Assessment may provide convincing evidence of abundant plastic pollution in the environment, the contribution of vinyl is much less clear.

To consider the question of cost effectiveness of management measures, a cost-benefit approach may be helpful. There is a substantial cost to both government and industry for implementing and enforcing regulations. In the case of vinyl, the benefit, if any, has not been demonstrated clearly. Therefore, it is arguable whether any regulatory action, for example, banning vinyl single-use plastics, would represent a “cost-effective” measure.

Finally, it is important to avoid inadvertently overestimating the threat posed by a chemical hazard. As noted previously, studies are often conducted at very high doses to try to elicit any effects that could occur - i.e. in a precautionary manner that overestimates real world exposure. Any adverse findings can be perceived by some people to represent a “threat of serious or irreversible harm.” While it can be appropriate to use high doses to see whether effects could occur, a real-world exposure scenario should form the basis of risk management decisions.

Disclaimer

This report was prepared by the undersigned solely for the account of the Vinyl Institute of Canada. The material documented herein reflects the author’s best judgment in light of the information available to the author at the time of preparation. Any use which a third party makes of this report, or any reliance on, or decisions made, by third parties based on this report are the responsibilities of such third parties. The author accepts no responsibility for damages, if any, suffered by any third parties as a result of decisions made, or actions taken, based on this report.

Closure

This completes my report for the current assignment. Please do not hesitate to contact me if I can be of further assistance.

Sincerely,

Ronald W. Brecher, PhD, DABT, CChem
Toxicology, Risk Assessment and Risk Communication Specialist

Cc: Aiñe Curran, Executive Director, Vinyl Institute of Canada

Encl. Attachment A - Review of Selected References

References

ECCC (2019). A proposed integrated management approach to plastic products to prevent waste and pollution.

Government of Canada (2020). Science Assessment of Plastic Pollution.

Attachment A

Summary of Selected Studies

Citations as per “Science Assessment of Plastic Pollution,” Government of Canada, 2020

Agarwal et al. (1978)

Bakir et al. (2016)

Chen et al. (2019)

De Haan (2019)

Espinosa et al. (2019)

Horn et al. (2019)

Jovanovic et al. (2018)

Lamb et al. (2018)

Lei et al (2018)

Peda et al. (2016)

Piggott and Ishmael (1979)

Prata (2018)

Renzi et al. (2018)

Slootmaekers (2018)

Stock et al. (2020)

Volkheimer (1975)

Wright et al. (2013)

Xu et al (2014)

Zhou et al. (2018)

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: