Summary of public comments received on the draft screening assessment and risk management scope for phenol, methylstyrenated (MSP)
The draft screening assessment and risk management scope for phenol, methylstyrenated (MSP) were published in November 2021 and were subject to a 60-day public comment period (Canada 2021). Comments on these two documents were submitted by a number of stakeholders. Given that the assessment for MSP has considered data submitted under the New Substances Notification Program, the number of stakeholders and their identities are considered as Confidential Business Information and are not released.
Summarized public comments and responses from the Government of Canada are provided below, organized by topic:
Overarching
Comment summary 1: Some stakeholders have identified information gaps in the draft screening assessment that they believe require more data.
Response 1: These gaps are acknowledged in the uncertainties section of the assessment.
Comment summary 2: Some stakeholders have provided additional data for MSP and analogues, as well as uses and commercial status of MSP in other jurisdictions. They commented that there are potential new users internationally and a wide range of uses; hence, the draft screening assessment does not include all possible applications of MSP.
Response 2: Information relevant to assessing MSP has been considered in the updated draft assessment.
The assessment has focused on sources and uses of MSP that have been notified and are expected in Canada. MSP is an organic substance of Unknown or Variable composition, Complex reaction products or Biological material (UVCB), consisting of different structural components produced by different manufacturers. Only the information on MSP currently relevant to the Canadian market and environment is considered in the assessment.
Information on sources and uses of MSP in other jurisdictions that the stakeholder provided has confirmed that the substance has a wide range of applications, which suggests a potential increase in use in Canada. Hence, it is appropriate to exercise precaution as was done in the assessment and to consider a risk management plan that addresses the substance broadly.
Comment summary 3: Some stakeholders have pointed out that the Government of Canada is the first country to conduct an assessment and propose risk management measures for this substance.
Response 3: There have been a number of evaluations of Significant New Activity Notifications (SNANs) for MSP. Assessment of information received in response to the SNANs suggest that releases of this substance may be harmful to the environment, resulting in Ministerial Conditions being imposed on some notifiers. The Government of Canada therefore decided to conduct an assessment for MSP, which proposes that the substance is an ecological concern and meets the criteria of section 64 of the Canadian Environmental Protection Act, 1999 (CEPA). The Government of Canada’s proposed risk management aims to minimize the long-term risks identified in the assessment, using the most appropriate tools. In addition to potential regulations, an amendment to, or rescission of, the Significant New Activity (SNAc) Order that applied the SNAc provisions to the substance and associated Ministerial Conditions may also be considered.
Methodology
Comment summary 4: Some stakeholders expressed concerns that the proposed conclusions in the draft screening assessment have been drawn on the basis of major components of the substance, instead of data for MSP as the substance.
Response 4: MSP is an organic UVCB. The approach used in this assessment is consistent with that which was used in past assessments. The approach is explained in the published literature (Salvito et al. 2020) where the fate, behaviour, and toxicity exhibited by the whole UVCB released to the environment can be predicted by using representative components in the mixture.
On the basis of available information, major components in MSP are monomethylstyrenated phenol, dimethylstyrenated phenol, and dimers of C9 monomers. Proportions of these major components in MSP are 3.5% to 21%, 10% to 50%, and 31% to 50%, respectively. The environmental fate, behaviour, and effects on organisms of the substance are assessed based on the available data for major components, as well as the data available for the UVCB itself.
Comment summary 5: Some stakeholders expressed concerns that the proposed conclusions in the draft screening assessment have been drawn using model predictions and read-across data for structural analogues.
Response 5: It is a standard practice in an assessment to use model predictions and read-across data to fill data gaps when there is a lack of empirical data. Professional judgement has been exercised in determining the analogues and the application of quantitative structure-activity relationship (QSAR) models, while also ensuring that proper weight is given to model predictions, with consideration of the domain of applicability, and to read-across data.
Comment summary 6: A stakeholder has recommended that risk ratios for individual components be added up when drawing the conclusion in the draft screening assessment.
Response 6: In the assessment of a UVCB that consists of a number of major structural components, the risk ratios (namely the risk quotients (RQs) in the assessment) can be calculated separately for each of the major components. These can be considered separately in the risk characterization, as has been done in this assessment, or summed.
RQs for dimethylstyrenated phenol and dimers of C9 monomer are individually above 1; the addition of RQs for these two components are also above 1. The summed approach would therefore not affect the conclusion in the assessment.
Sources
Comment summary 7: A stakeholder has expressed concerns that 10 000 to 100 000 kilograms import of MSP per year, as stated in the draft screening assessment, has not accurately reflected the estimated import of this substance into Canada.
Response 7: The MSP quantities in commerce reported by SNAN notifiers were described in the assessment to be in the range of 10 000 to 100 000 kilograms per year (kg/yr). This range pertains to import quantities and does not consider any quantity (below 100 kg/yr) manufactured in Canada.
Some revisions have been made in the updated draft assessment to present this more clearly.
Environmental distribution
Comment summary 8: Some stakeholders have expressed concerns that differential migration of MSP components through an overcoat paint film into the water column is not mentioned.
Response 8: There is no need to consider differential migration of MSP components through an overcoat because migration-controlled release quantities are neither required nor estimated in the environmental fate analysis. Some edits have been made in the ecological exposure characterization section of the updated draft assessment to clarify this. In addition, in the exposure characterization section, only the losses from overspray are considered as a relevant source of environmental exposure.
Persistence
Comment summary 9: A stakeholder has provided comments on the degradation pathway of antioxidants and suggested that MSP may undergo some biodegradation in the environment.
Response 9: Information relevant to MSP has been considered in the updated draft assessment.
Comment summary 10: Some stakeholders have expressed concerns with the conclusion that MSP meets the regulatory criteria for persistence. They noted a conflict in data that are available for two components of MSP in the European Chemicals Agency (ECHA) database.
Response 10: As explained in Salvito et al. (2020), the assessment of the environmental fate and behaviour of MSP, a UVCB, is based on the assessment of its major components, as well as the substance itself.
Empirical data from ready biodegradation studies indicate that monomethylstyrenated phenol and a dimer of C9 monomer, as well as MSP, are not expected to undergo rapid degradation. Some degradation of monomethylstyrenated phenol and dimers of C9 monomer has been reported in biodegradation studies, using a test enhanced for conditions favouring acclimation. The acclimated systems in biodegradation studies are generally less relevant when extrapolating to environmental conditions such as surface waters as they are not reflective to these conditions. Considering the weight of evidence including results from the ready biodegradation studies and QSAR model results, MSP and two of its major components, monomethylstyrenated phenol and dimers of C9 monomer, are expected to be persistent in the environment.
Bioaccumulation
Comment summary 11: A stakeholder has expressed concerns on the conclusion that MSP meets the criteria for bioaccumulation potential. The stakeholder pointed out that among the major components in the substance, only the measured bioconcentration factor (BCF) for a dimer of C9 monomer is within the range of 2 000 to 5 000 L/kg, suggesting a low-to-moderate potential for bioaccumulation, according to Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) criteria.
Response 11: Since dimethylstyrenated phenol and dimers of C9 monomer possess high log KOW (6.2) and low water solubilities, it is important to consider exposure via food in addition to uptake via water. Therefore, the bioaccumulation factor (BAF) is considered more appropriate to characterize the bioaccumulation potential. Due to a lack of empirical BAFs, a model, which was considered applicable to predict BAFs for the major components in MSP, was used. The modelled BAFs for dimethylstyrenated phenol and dimers of C9 monomer are above 5 000 L/kg, indicating that MSP meets the regulatory criteria for bioaccumulation in aquatic organisms.
Ecological effects assessment
Comment summary 12: Some stakeholders have questioned the source of fish toxicity data for MSP, presented in the draft screening assessment.
Response 12: The effects data (96-hour LC50 (LC50, median lethal concentration) = 3.46 mg/L on fish) presented in the draft screening assessment was converted from the original data (96-hour LL50 (LL50, median lethal loading) = 25.8 mg/L) identified in the ECHA database (ECHA c2007-2023) by using the measured total organic carbon (TOC) in the testing solution, the geometric mean of the ratios for TOC and the molecular weight for major components in MSP. To present this information more clearly, the original data reported in ECHA (c2007-2023) has been included in the updated draft assessment instead.
Comment summary 13: Some stakeholders have provided comments on the different risk assessment approaches between what was used in the draft screening assessment and what is applied by REACH in the European Union, particularly the use of the non-classical assessment factor, FMoA, to account for a “non-narcotic” mode of action.
Response 13: The use of assessment factors to extrapolate predicted no effect concentrations (PNECs) has been explained in the draft screening assessment. The method is a new approach that was developed for the assessments under the Chemicals Management Plan in Canada. Details of this approach was published in a peer-reviewed journal and this reference (Okonski et al. 2021) has been added in the updated draft assessment.
Exposure assessment
Comment summary 14: Some stakeholders provided details on the application methods of MSP-containing paints.
Response 14: Information on application methods of MSP-containing paints has been considered in the updated draft assessment, if relevant to the notified uses in Canada.
Comment summary 15: A stakeholder has commented that paints (an ingredient in epoxy-based primer) containing MSP are imported into Canada as opposed to the importation of MSP for formulation into paint products. It is stated that a greater portion of paints with MSP are primers. The UVCB components are expected to be embedded in the MSP-matrix, and even more in the final article, so are not/hardly mobile -- namely, their environmental availability is greatly reduced. Thus, any potential adverse impact on aquatic/environmental life during intended applications is expected to be significantly suppressed.
Response 15: Edits are made in the updated draft assessment to clarify that formulation does not occur in Canada.
The exposure assessment focused on releases from the use of MSP-containing products, where releases are expected from overspray during application of the product. Quantities embedded in the MSP-matrix for cured paints are not considered as being released. To account for this, an emission factor was used to represent the net fraction released via overspray to the aquatic environment. The updated draft assessment has been revised to make this clear.
Comment summary 16: Some stakeholders have provided comments indicating that there was a lack of clarity as to why the “on-dock” scenario led to direct releases.
Response 16: Clarifying text was added to the ecological exposure assessment section of the updated draft assessment to explain why ship painting results in direct entry into waters and large equipment painting results in indirect entry.
Comment summary 17: A stakeholder has commented that the SimpleTreat model excludes technical pre-cleaning stages, which are common for certain industrial waste streams.
Response 17: The removal estimates used in the calculations represent the realistic worst-case scenario by excluding industrial on-site wastewater treatment. This recognizes variations between facilities, where cases of no removal by pre-cleaning cannot be ruled out. Clarifying text was added to the ecological exposure assessment section of the updated draft assessment.
Comment summary 18: A stakeholder has commented on the changes of physical-chemical properties of MSP during the production of coatings and also during the different steps of the coating procedure itself, which are not fully considered, so that the calculated exposure scenarios are not representing realistic worst cases. In addition, the predicted environmental concentration (PEC) calculations are not considered to be very transparent and easy to understand.
Response 18: The exposure assessment has considered the most appropriate data and estimates available to inform the exposure assessment, and calculated PECs reflecting a realistic worst-case scenario. The combination of the emission factor and the SimpleTreat 3.1 (2003) removal estimates represents the realistic worst-case scenario. Revisions have been made in the ecological exposure assessment section of the updated draft assessment to improve clarity. Equations and inputs for the PEC calculations are included in the text and in Appendix A of the updated draft assessment.
Comment summary 19: A stakeholder commented that it seems unlikely that levels in drinking water would be as high as those estimated in surface water.
Response 19: Surface water concentrations were used as a conservative estimate of exposure. As exposure to this substance to the general population in Canada was a low concern, no further refinements were deemed necessary.
Risk management
Comment summary 20: Some stakeholders have provided specific recommendations for the previous risk management scope.
Response 20: These recommendations, where applicable, have been considered in the revised risk management scope.
Comment summary 21: Some stakeholders expressed concerns regarding changes to the current risk management of MSP and the proposed strategy described in the previous risk management scope. Stakeholders have made recommendations on the risk management of MSP, in particular to continue to allow the import of MSP with conditions.
Response 22: The Government of Canada’s proposed risk management aims to minimize the risks identified in the updated draft assessment using the most appropriate tools. Selection of the proposed risk management options or instrument is made using a thorough and consistent approach that takes into consideration information in the assessment and other sources of information, including stakeholder input and socio-economic factors.
Preventing or controlling risks from toxic substances is done by selecting and applying risk management instruments that are most likely to achieve environmental objectives.
Given that MSP is proposed to meet all of the criteria in CEPA paragraph 77(3)(a) and that the recommendation is to add MSP to Part 1 of Schedule 1 to the Act, the ultimate environmental objective for this substance will be elimination via prohibition, in order to prevent or minimize adverse effects on the environment. Priority consideration of prohibition is required for substances recommended for addition to Part 1 of Schedule 1 to CEPA. Regulations to prohibit the manufacture, use, sale, offer for sale, and import of MSP and products containing the substance would help to achieve this objective and requirement, while addressing the risks to the environment posed by MSP.
Specific time-limited exemptions could be considered in exceptional circumstances, taking into account socio-economic factors and the demonstrated absence of suitable alternatives with consideration of environmental risks. In addition to potential regulations, the rescission of the SNAc Order that applied the SNAc provisions to the substance and associated Ministerial Conditions may also be considered.
Comment summary 23: Some stakeholders provided information on potential socio-economic impacts of the proposed risk management strategy, including potential downstream impacts.
Response 23: The Government of Canada is committed to consulting with affected stakeholders when developing risk management options for MSP.
Information on potential socio-economic and technical impacts, including potential impacts to downstream users of products containing MSP, will be considered as risk management is developed. A cost-benefit analysis and regulatory impact analysis statement is developed and published with each proposed regulation.
The Government of Canada welcomes any additional information and quantitative data to help further evaluate socio-economic and technical impacts.
Comment summary 24: Some stakeholders provided information regarding reformulation and alternatives to coatings products that contain MSP.
Response 24: In developing risk management scopes and approaches for substances of concern, the Chemicals Management Plan considers existing information regarding potential substitutes and alternatives including relevant information on economic, social, and environmental implications for Canada.
It is expected that alternatives to coatings containing MSP are available. However, further information is being requested from stakeholders. Environment and Climate Change Canada (ECCC) welcomes additional information on alternatives to MSP or MSP-containing products, on product reformulation, and on testing and costs associated with coatings that contain MSP. Available information regarding the performance of coatings that contain MSP, timing and costs associated with reformulation, and potential alternatives to coatings containing MSP will be considered as risk management is developed.
Comment summary 25: Stakeholders commented that Canada’s risk management approach is not aligned with that of the United States or the European Union.
Response 25: The Government of Canada seeks alignment with other jurisdictions where possible and practical. However, variations between jurisdictions often occur due to differences in regulatory regimes, as well as differences in uses and use quantities of substances. Risk management alignment with other jurisdictions will be considered where appropriate as risk management is developed.
Comment summary 26: Stakeholders have provided information on the properties of MSP in coatings products containing MSP.
Response 26: ECCC welcomes any additional information or quantitative data regarding MSP’s use in coatings.
The benefits of formulations of coatings that contain MSP will be considered as risk management is developed.
References
Canada. 2021. Publication of results of investigations and recommendations for a substance — phenol, methylstyrenated (MSP), CAS RN 68512-30-1. Canada Gazette, Part I, Vol. 155, No. 45.
[ECHA] European Chemicals Agency. c2007-2023. Registered substances database; search results for CAS RN 68512-30-1. Helsinki (FI): ECHA. [accessed 2018 December].
Okonski AI, MacDonald DB, Potter K, Bonnell, M. 2021. Deriving predicted no-effect concentrations (PNECs) using a novel assessment factor method. Hum. Ecol. Risk Assess. 27(6): 1613-1635.
Salvito D, Fernandez M, Jenner K, Lyon DY, de Knecht J, Mayer P, MacLeod M, Eisenreich K, Pim Leonards P, Cesnaitis R, León‐Paumen M, Embry M, and Déglinl SE. 2020. Improving the Environmental Risk Assessment of Substances of Unknown or Variable Composition, Complex Reaction Products, or Biological Materials. Environ Toxicol Chem 39 (11): 2097-2018.
SimpleTreat [Sewage Treatment Plant Removal Model]. 2003. version 3.1. Bilthoven (NL): National Institute for Public Health and the Environment (RIVM). Available from: National Institute for Public Health and the Environment (RIVM), Laboratory for Ecological Risk Assessment, Bilthoven, the Netherlands.