Summary of public comments received on the screening assessment report for the phthalate substance group
Comments on the draft Screening Assessment Report (SAR) for the Phthalate Substance Grouping to be addressed as part of the Chemicals Management Plan (CMP) were provided by 3M Canada Company, American Chemistry Council, Beautycounter, Canadian Consumer Specialty Products Association, Canadian Vehicle Manufacturers’ Association (CVMA), Ecolab, Electronics Product Stewardship Canada, Environmental Defence and Ecojustice, Global Automakers of Canada, IBM Canada Ltd., Industry Coordinating Group - Technical Sub-committee, KAND EHS Services, Miriam Diamond (University of Toronto), PPG Canada Inc., Prevent Cancer Now & Chemical Sensitivities Manitoba (joint submission), The Vinyl Institute, and Valtris Specialty Chemicals.
A summary of comments and responses provided by the Government of Canada is included below, organized by topic:
1. New information and data
| Summarized comment | Summarized response |
|---|---|
| Sound science is recognized as a strength of the CMP program. Detailed comments related to the phthalate substance grouping draft screening assessment will be provided under separate cover to assist with ensuring that up-to-date and accurate information is available for the final screening assessment. This includes information on substance structure and composition, volumes and uses, environmental monitoring, solubility, and toxicity. These data can be expected to have a significant impact on the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC). | The screening assessment considers all recent and relevant data pertaining to the phthalates that are subject to assessment, including information relating to their chemical structure, physical and chemical properties, volumes and uses in Canada, environmental fate, exposure potential, and toxicity. |
| Many studies in Table 9-32 are cited as showing “limited evidence” of an association between the phthalate substance 1,2-Benzenedicarboxylic acid, di-C8-10-branched alkyl esters, C9-rich; 1,2-Benzenedicarboxylic acid, diisononyl ester (DINP) and sex hormone levels. For clarity, it would be helpful to explicitly define “limited evidence”, as well as providing more detail on the nature of those limitations. The assessment should provide a link to Appendix F of the DINP State of the Science Report where “limited evidence” is defined and include a link to details on what those limitations are. | The screening assessment was revised to include definitions for the terms “no evidence”, “inadequate evidence”, and “limited evidence” as a footnote to the relevant tables. More details regarding how studies are evaluated and how the level of association is determined are provided in the supporting documents (Health Canada 2018c; 2018d), available upon request. |
| Quantitative structure-activity relationship (QSAR) estimates should be used in the assessment to estimate the octanol-water partition coefficient (Kow) and water solubility. The phthalate substance 1,2-Benzenedicarboxylic acid, benzyl C7-9-branched and linear alkyl esters (B79P) has a very low water solubility. Since solubility and log Kow measurements are highly variable for phthalates, the assessment should list the solubility of B79P as ranging from 2.6 to 4.6 μg/L, based on QSAR estimates. | Additional information submitted was considered and the screening assessment was revised. QSAR models were used to generate physicochemical property data for B79P, which are presented in the final screening assessment. The water solubility value selected for the screening assessment was 0.25 mg/L: this is the harmonized value based on four QSAR models. |
| B79P is a specialty low volume phthalate only used in industrial applications. | The additional information for B79P supports information already considered in the screening assessment. |
| The screening assessment does not appear to consider recent studies on dietary exposures through dairy, meat, and processed cheese (including cheese powder in macaroni and cheese products) nor studies on human reproductive and developmental effects. | As indicated in Appendix E, Derivation of dietary intakes, of the screening assessment, dietary exposure was estimated based on phthalate occurrence data from the 2013 Canadian Total Diet Study (TDS). The TDS was the most comprehensive, relevant, and recent study available. It analyzed several phthalates in 159 composite food samples, including different meat and dairy composite samples, such as processed cheese. Where data gaps existed, food occurrence data were taken from other sources. These are identified in Table E-1. More details regarding epidemiological studies for phthalates are provided in supporting documents (Health Canada 2018c; 2018d) and are available upon request. |
| Due to changes in the manufacturing process, the composition of B79P has changed over time. The substance should now be placed in a different subgroup within the assessment, based on its higher molecular weight. | This additional information was considered and the screening assessment was revised. While B79P remains in the medium-chain phthalate subgroup based on its molecular weight, the updated physicochemical properties including lower water solubility were considered when determining the potential risk to the environment for this phthalate. |
| The 22-day Daphnia magna study used for B79P is not available; however, a cover page giving a brief summary of the study indicates the endpoint of 0.039 mg/L is for survival rather than for reproduction, as stated in the draft screening assessment. | The 22-day Daphnia magna study summary used in the screening assessment to derive the PNEC was accessed from the online European Chemicals Agency (ECHA) database for registered substances. This study has now been removed from this website and is therefore no longer considered in the final screening assessment. |
| The screening assessment seems to be missing data on indoor environment exposure and human exposure, especially prenatal exposure, even though quite a lot of published data are available. | The most recent and relevant data that could be identified for all phthalates were considered in the assessment, including data on exposure estimates from environmental media and food, as well as inhalation of air and ingestion of dust from indoor environments. |
| The phthalate substance 1,2-Benzenedicarboxylic acid, bis (2-propylheptyl) ester (DPHP) has functional characteristics similar to 1,2-Benzenedicarboxylic acid, diisodecyl ester (DIDP) and can be used as an alternative to DIDP. This is not indicated in the draft screening assessment. DINP, DIDP, and DPHP are meant to replace 1,2-Benzenedicarboxylic acid, dibutyl ester (DBP), 1,2-Benzenedicarboxylic acid, butyl(phenylmethyl) ester (BBzP or BBP), and 1,2-Benzenedicarboxylic acid, bis(2-ethylhexyl) ester (DEHP). The screening assessment is missing a direct comparison of DINP, DIDP, and DPHP, as well as their relevant uses. | DPHP was evaluated in 2004 under the Canadian Environmental Protection Act 1999 (CEPA 1999) New Substances Notification Regulations and was concluded to not meet CEPA toxic criteria. Therefore, it was not prioritized for further assessment as part of the Phthalate Substance Grouping. However, a Significant New Activity Notification (SNAc) was applied to the substance under subsection 81(3) of CEPA. Application of this SNAc requires reporting to the Government of Canada any new activity involving use of DPHP in the formulation or manufacture of products used by children from 0 to 6 years of age. New activities under these conditions will result in further assessment of the substance. |
| There is a data gap on the fate of plasticized waste in Canada. | The screening assessment focused on releases of the 14 Phthalate Grouping substances to the environment. Plastic waste management is a priority for the Government of Canada that involves leading and participating in national and international initiatives to effectively manage plastics and reduce plastic waste in the environment. |
| RQ calculation for the individual phthalates in the Phthalate Substance Grouping determined that there is a risk to aquatic organisms from B79P and from the additional phthalate DEHP. RQs for the additional phthalates, which are not being assessed, ranged from 1.2 × 10-3 to 0.58. Human data should be included in the screening assessment. | Data relevant to the evaluation of potential effects in humans were not considered in the evaluation of potential for risk to aquatic organisms. However, these data were considered in evaluating the potential to cause harm to human health. |
| It is unclear if DEHP concentrations in poultry were available and if DEHP concentrations would differ between cooked and raw vegetables. | All monitoring data that was available at the time of the assessment were considered, and data gaps, if any, were captured as uncertainties in the assessment report. |
| Provide clearer explanation where mono-ester vs. di-ester species were measured in biomonitoring and how these different species were accounted for in the assessment. | Appendix C of in the screening assessment explains how daily intakes for 1,2-Benzenedicarboxylic acid, butyl phenylmethyl ester (BBP), DBP, and DEHP were derived using mono-ester metabolites measured in urine. For all other phthalates with biomonitoring data, the explanations can be found in the corresponding appendices of the State of the Science Reports: DIDP in Appendix D, DINP in Appendix E, DMP in Appendix F, and DIBP in Appendix G. |
| Clearly indicate in the screening assessment when endocrine information/endpoints are used. | The assessment report was updated with additional detail from relevant new and existing studies. |
| Information was provided regarding activities for one of the substances 1,2-Benzenedicarboxylic acid, diethyl ester (DEP), to help inform the choice of follow-up activity. | Noted. |
| Additional information was provided. | The additional information was considered and the screening assessment was revised. |
2. Methodology
| Summarized comment | Summarized response |
|---|---|
| We urge caution in using reverse dosimetry as this methodology has numerous unresolved questions. | Noted. The methodology used to derive daily intakes is explained in Appendix C of the screening assessment and also in the State of the Science Reports, in Appendix E for DINP; Appendix G for DIBP; Appendix D for DIDP; and Appendix F for 1,2-Benzenedicarboxylic acid, dimethyl ester (DMP). |
| Mechanisms for Addressing new uses of CMP3-Assessed Chemicals (MAAC) may be overused under the CMP, as it seems to have been proposed for many substances recently. However, organizing plans for tracking into a transparent and clearly described framework (i.e. MAAC) may help to make this more workable, while not stigmatizing the many safe uses of so many substances found to not meet the CEPA Toxic criteria. | Mechanisms such as the Identification of Risk Assessment Priorities process are applied by the Government of Canada to monitor new information on substances and the potential for substitution. The Government of Canada is also exploring ways to advance responsible replacement of chemicals of concern, including ways to apply informed substitution to support chemicals management (Combined government discussion paper and science committee report on informed substitution. Publication date: 2018-08-28). |
| There is no known commercial test methodology to accurately measure B79P in water. It is understood that Environment and Climate Change Canada (ECCC) has developed a methodology but that it has not yet been peer reviewed. It is troubling that a draft conclusion of toxic is being considered based on results that cannot be replicated or verified. In addition, a very limited sample size was collected for a study which would not be considered statistically valid. ECCC is encouraged to take the steps necessary to validate the testing methodology and conduct a sound sampling program before proceeding on any risk management considerations. | The analytical method used to measure concentrations of B79P in effluent samples was refined after receiving additional information on its composition. The revised method was validated by comparing it to the analytical method used by the primary manufacturer of B79P, and a commercial laboratory experienced in phthalate analysis. The data from wastewater treatment system (WWTS) samples that was used to derive PECs were re-analyzed using the refined method. The WWTS sampling program also added 15 WWTSs, increasing the total number of WWTSs sampled to 31. The resulting revised analyses for B79P found that it does not to meet Section 64 of CEPA and the screening assessment was revised. Government of Canada researchers developed and documented an analytical method for analyzing phthalates including B79P that will be published in a peer-reviewed journal. |
| It would be surprising to find any B79P in a WWTS effluent sample due to the low use levels and the high elimination (>95%) by typical municipal systems. | B79P was present at low concentrations in some WWTS influent and effluent samples, but generally at levels that were below the calculated method detection limit of 0.88 µg/L. |
| The WWTS monitoring data does not detect DINP, the largest volume plasticizer used in Canada, so it seems unlikely that B79P would be detected, given its lower use volumes. | Although the modelled PEC used in the DINP RQ analysis was based on Section 71 survey data, it is also consistent with concentrations measured in a monitoring study conducted by ECCC in 2014-2017 (ECCC 2018). Due to DINP’s physicochemical characteristics (e.g. low water solubility and high partition coefficients), it tends to bind with organic material when it is in water. DINP entering a WWTS is therefore expected to bind to biosolids rather than remain in the aqueous phase, consequently reducing concentrations in the effluent. |
| There are study quality limitations with Li et al. (2015b) that make selection of a point of departure based on that data questionable. For example, in Li et al. the study authors conducted statistical evaluation on an individual, not litter, basis. If being conducted for regulatory action purposes, the litter should be used as a statistical unit as the value may not have been identified as the lowest observed adverse effect level (LOAEL) if the appropriate statistical unit was utilized (i.e. cannot differentiate between a potential litter effect as opposed to an effect of the chemical which would be present across litters). | While there are some limitations with the study conducted by Li et al. (2015b), similar effects such as multi-nucleated gonocytes and Leydig cell cluster effects were observed in other studies (Clewell 2011; Clewell 2013) at 250 mg/kg-bw/day and above. A Hazard Index (HI) above one indicates a potential risk. Since the HI was below one, closer evaluation of these studies was not considered, and there was no further refinement of the screening assessment. |
| In Table 9-32, the few associations reported between DINP and sex hormone levels are very weak, inconsistent with results of similar studies, and are generally not observed with decreases in more closely-related, clinically relevant measures of fertility (e.g. sperm quality). Without contextualized information, a reader may assume that “limited evidence” has a more profound interpretation than the data supports. A clarifying statement should be added to avoid such a situation. | More details regarding how studies are evaluated and how levels of association are determined are provided in supporting documents (Health Canada 2018c; 2018d), available upon request. |
| Determination of metrics such as the HI should be qualified with information regarding data strengths and limitations, including sensitivity. Poor quality information should not be substituted for evidence of lack of harm. | Screening assessments conducted under the CMP consider multiple lines of evidence to determine if a substance may pose a risk to human health. Health effect endpoints are used to derive the hazard quotient (HQ) and the resulting HI. This approach is described in the Proposed Approach for Cumulative Risk Assessment of Certain Phthalates under the Chemicals Management Plan. |
| The draft assessment is fair and a reasonable representation of the potential conditions that exist in Canada for phthalates. The additive methodology used in this assessment was a reasonable approach. | Noted. |
| The screening assessment recognizes that further refinement to a higher tiered analysis may be required to confirm a conclusion. This practice should be encouraged throughout Chemicals Management Plan (CMP) assessments. | Noted. |
| Health Canada conducted a lower tier assessment, using conservative assumptions with a low degree of refinement. The approach used was in line with the proposed approach published in 2015. Further refining of this, or any cumulative risk assessment, should include the consideration that some of the chemicals might appropriately be excluded from higher tier assessments, as the data warrants. | Noted. |
| The cumulative assessment used is effective for substances like phthalates, which have well-defined properties, but might be inadequate for substances with complex chemistry or non-traditional solution behaviour. | Noted. |
3. Uses
| Summarized comment | Summarized response |
|---|---|
| It is quite common to have plastic flooring in Canadian apartment buildings. | Dermal and/or oral exposures to plastic articles, including flooring, were estimated where relevant (i.e. DIBP, B84P, B79P, DINP, DIDP, and DUP). |
| It would be beneficial to provide more extensive discussion on the key sources of uncertainty related to the cumulative risk assessment and their impact. | Uncertainties associated with the lines of evidence, stemming from data gaps or limitations were identified and their impact on the assessment were characterized qualitatively. Uncertainties can lead to over- or under-estimation of risk, or the impact can remain unknown. Section 4.5 “Uncertainties of the Health Approach” in the Proposed Approach for Cumulative Risk Assessment of Certain Phthalates under the CMP provides additional discussion. |
| Table 4-2 shows that 1,2-Benzenedicarboxylic acid, heptyl nonyl ester, branched and linear (79P) is still significantly used, but more details about usage are needed. | Information on phthalate uses in Canada is provided in the Uses section of the screening assessment, as well in as the State of the Science reports for the various phthalate subgroups. 79P is one of 14 additional phthalates selected for use in the cumulative risk analysis. Since the additional phthalates were not assessed, a detailed examination of their uses in Canada was not considered. However, 79P is under consideration for follow-up activities. |
| Nail polish and body lotion should not be grouped together, since the exposure potential of these two product types differs. | Body lotion and nail polish are grouped in Table 9-5 because they are both leave-on products. However, estimates of exposure for nail polish are also presented separately in Table 9-6. |
4. Sources and releases
| Summarized comment | Summarized response |
|---|---|
| Better information on quantities of the substances present in Canada may be required if further refinement to the screening assessment is conducted. | The screening assessment considers all recent and relevant data for quantities of phthalates present in Canada, including data regarding import, export, and use of phthalates. Quantities are presented as ranges to protect the confidentiality. |
| Many widely used phthalates display physical properties that should prevent these substances from significant human or environmental exposure when properly used in vinyl materials. Future evaluations must consider these properties and ensure that scientific evidence of sufficient quality is obtained and weighed before making regulatory decisions. | The assessment considered many sources of phthalates into the environment, not only those related to vinyl materials. Monitoring data indicating the measured presence of phthalates in all environmental media confirms that these substances can be released from products and enter the environment. |
| It will be important that the Government of Canada continue accurate communications to Canadians about the safe use of substances. Phthalates are a family of substances used in hundreds of products in homes, hospitals, cars and businesses. There are different types of phthalates with a wide range of physical and chemical properties. While they can be employed in a variety of applications, phthalates are not interchangeable. It is important that the facts continue to be accurately provided in context, as this initiative moves forward. | Noted. The “What can Canadians do?” section of the Information Sheet on the Phthalate Substance Grouping provides information to the public on safe use. |
| The frequency of detection of DEHP was much higher in WWTS influents than in WWTS effluents (83 out of 90 vs. 15 out of 90), and the detections in WWTS effluents for DEHP were among the lowest of the phthalates tested. This is not unexpected, as biological wastewater treatment should be effective at eliminating DEHP. | Noted. |
5. Risk characterization
| Summarized comment | Summarized response |
|---|---|
| Since the RQ of 0.95 for B79P is extremely close to the boundary and within the error of the analysis (and the approach), it is strongly suggested the B79P recommendation be set aside and further refinement of the analysis be undertaken to increase confidence in the program and bring credibility to the decision. | The RQ for B79P was revised based on new information and B79P is now considered to present a low risk of harm at current exposure levels. However, there is evidence that it may adversely affect endocrine systems. For this reason, B79P was identified as having the potential to be highly hazardous, should environmental exposure levels increase. |
| The RQ of 23.3 for DEHP is sufficiently greater than the boundary value of 1 to support the proposed CEPA toxic conclusion for DEHP. | The PEC range reported for DEHP in the screening assessment was unchanged following the incorporation of new monitoring data from an expanded WWTS sampling campaign, supporting the RQ of 23.3 determined for this substance. |
| The indoor environment is a very important contributor to DEHP exposures and consideration should be given to the impact of direct sunlight against DEHP-containing products. | Indoor environments are considered a source of exposure for DEHP. Table D3-A in the screening assessment includes indoor air and dust exposure data for calculating daily intakes of DEHP. |
| The detection limit range of 0.0013 to 0.013 mg/L provided in the screening assessment for DEHP in water is several orders of magnitude higher than the PEC and PNEC values used in the risk quotient. It is understood that the PEC for DEHP is not an observed value based on data. It is rather a modelled value that is based on industrial emission factors and quantities reported under Section 71. However, Table 8-4 in the screening assessment includes statistics on the number of detections of DEHP in WWTS influents and effluents. If DEHP was present above the detection limit in the samples taken during the Monitoring and Surveillance Program, then that data would be more relevant to the risk assessment than modelled values. | The PNEC reflects the extensive scientific data that demonstrates DEHP’s potential to cause adverse effects at very low environmental concentrations. The PNEC is a calculated value that incorporates both a reliable low-effects value and an assessment factor that considers elements such as differences in species sensitivity and extrapolation to long-term effects. The approach for determining PEC values considered both monitoring data and modelled data from locations where DEHP was used but not monitored. Modelled values were derived using Section 71 quantities to which industrial emission factors were applied. The highest PEC value was based on the modelling approach that considers use quantities and release potential. Multiple PECs were also calculated based on monitoring data that measured DEHP above detection limits. The screening assessment was revised to present the median value and highest value of these PECs. |
| The State of the Science Report for DMP does not justify use of a short-term rather than a chronic dermal endpoint for risk characterization of exposures to hair dye. Hair dye use is repeated and can be over several decades of the lifetime. As such, comparison to the chronic dermal endpoint is warranted. | Table 9-5 in the State of the Science Report for DMP identifies dermal exposure from use of hair dye as being acute. Since permanent hair dyes are used on an intermittent basis (i.e. 8 times/year for adults; Bernard et al. 2016), using the short-term dermal endpoint was considered appropriate to characterize risk. |
| The draft screening assessment identifies a no-observed-adverse-effect level (NOAEL) for developmental toxicity of B79P after gestational exposure as the lowest tested dose (ECHA 2013). However, adverse effects could occur at this dose or lower doses. | The ECHA (2013a) study tested various doses of B79P for developmental effects based on oral exposure during the gestational period. High doses (e.g. 250 mg/kg bw/day and above) were shown to cause significant negative effects to the reproductive system of male rats within 21 days after birth. No adverse effects were observed at 50 mg/kg bw/day, the lowest dose tested. Therefore, the lowest dose tested was used as the NOAEL. |
| The screening assessment should indicate that there are no data on B79P on which to base a critical toxicity value for a specific mode of action. | The Critical Body Residue (CBR) calculation for B79P indicates that the substance is unlikely to reach levels where it would cause acute or chronic lethal effects in aquatic organisms, based on a narcosis mode of toxic action. However, CBR thresholds have only been developed for neutral narcosis modes of toxic action. Modelled chronic values for fish, Daphnia, and green algae suggest that chronic effects are possible. Additionally, the ECHA (2017) report concluded that B79P has the potential to cause developmental and reproductive effects and could adversely affect endocrine systems in mammals. This is consistent with modelled results indicating that B79P and its metabolites can bind with rodent estrogen receptors. Collectively, this evidence suggests that B79P may be highly hazardous because of its potential to affect the endocrine system. It is not expected to pose a risk under current exposure levels in Canada, but could become hazardous if exposure concentrations in the Canadian environment were to increase. |
| It is difficult to determine how Health Canada would have refined the assessment if HIs had been greater than 1. Several aspects of the screening assessment would need to be refined before being appropriate to assess potential risk for regulatory action. | Based on current levels of exposure, the conservative, lower tiered HI approach did not show a concern for the potential cumulative risk of medium-chain phthalates for the general Canadian population, including susceptible subpopulations. Further refinements to the hazard and exposure estimates were therefore not deemed necessary. |
| The screening assessment is lacking information on cumulative exposure effects in aquatic organisms. | An evaluation of cumulative exposure effects in aquatic organisms determined that, at current exposure levels of phthalates in Canada, there is low potential for cumulative risk through a narcotic mode of action. Cumulative risks based on other modes of action were not assessed because identification of a single non-narcotic mode of action in aquatic organisms that was common to all of the phthalates was not possible. In addition, methods to evaluate cumulative exposure effects for modes of action other than narcosis (such as CBR for endocrine-mediated effects) were not available. |
| The statement “an increase in exposure levels could represent a potential risk to human health” may convey a higher level of concern than is justified based on this screening assessment. To more accurately describe what an increase in exposure levels could represent, it is recommended to change this statement to “an increase in exposure levels could represent a potential elevation in the hazard index (HI) levels and a need for more in-depth assessment to determine whether there might be a risk to human health”. | This text is standard wording in CMP assessments for substances with certain health effects of concern. When a screening assessment notes that “an increase in exposure levels could represent a potential risk to human health”, the Gazette Notice provides information on “consideration for follow-up”, meaning that activities to track changes in exposure and/or commercial use patterns are under consideration for the substance. |
| The draft screening assessment did not consider exposures to DINP for infants from mouthing toys as part of the cumulative risk assessment. | The cumulative risk assessment considered DINP based on biomonitoring data for all age groups. This approach is expected to capture multiple potential exposure sources and routes, including products available to consumers. |
| In the case of certain phthalates, physicochemical property considerations indicate dramatically low exposure potential. The low exposures found in the draft screening assessment reflect the constraining force of these physical properties. If a higher-tier assessment were needed, it would need to address the physicochemical properties in more detail. | Noted. |
6. Human health assessment
| Summarized comment | Summarized response |
|---|---|
| Table 9-5 reports the range of DBP concentrations measured in cosmetics and personal care products. This table and the associated discussion would benefit substantially from including a measure of central tendency (e.g. mean or median) in these various product categories. | The detection frequencies are low for DBP in most cosmetics and personal care products. Reporting a mean or median would therefore not be meaningful. |
| Health Canada indicated that adverse reproductive effects for phthalates were found to persist into adulthood, based on a conservative selection of endpoints. For DINP, it does not appear that Health Canada considered persistence to adulthood. A statement should be added to specify that further refinement of the CRA could exclude some phthalates from the assessment. | Consistent with a tiered approach to risk assessment, CMP assessments do not attempt to describe what may be the impacts of further refinement. |
| The screening assessment lacks consideration of human data for DEHP, DIBP, DCHP, DBzP, and B79P. | As indicated in the screening assessment, more details regarding epidemiological studies are provided in supporting documents (Health Canada 2018c; 2018d), available upon request. The supporting documents present human data on the phthalates included in the screening assessment. This list of human epidemiological studies was updated for the final screening assessment. |
| More discussion and consideration are required in the screening assessment to address the weight of evidence that current exposures to medium chain phthalate esters are causally related to adverse health effects in human populations. | The screening assessment evaluates multiple lines of evidence to determine if a substance may pose a risk to human health or to the environment. Additional details regarding the epidemiological studies evaluated for this screening assessment are provided in supporting documents (Health Canada 2018c; 2018d), available upon request. While some studies report associations between phthalate exposure and human health, Health Canada and other jurisdictions recognize that these studies may have limited applicability when it comes to risk characterization in a regulatory context. |
7. Ecological assessment
| Summarized comment | Summarized response |
|---|---|
| The aqueous solubility of B79P falls well below the reported no observed effect concentration (NOEC) of 0.039 mg/L and lowest observed effect concentration (LOEC) of 0.094 mg/L. Hence, the toxicity test was conducted using concentrations well above the aquatic solubility of B79P and showed no toxicity at the solubility limit. | Empirical aquatic toxicity data for B79P indicate low potential for acute adverse effects in aquatic organisms, up to the limit of water solubility. This is supported by modelling results which predict that B79P will have no acute aquatic effects at substance saturation. However, modelled chronic values for fish, Daphnia, and green algae suggest that chronic effects are possible. |
| The use of a very low magnitude PNEC value for DEHP presents greater uncertainty. Consideration should be given to enhanced validation of this low PNEC. | PNECs are calculated based on a critical toxicity value (CTV) to which an assessment factor (AF) is applied. The screening assessment used a CTV for DEHP of 0.0002 mg/L, for significantly reduced embryo production in zebrafish (Corradetti et al. 2013). An AF of 3 was applied, which yielded a PNEC of 0.00007 mg/L. Other empirical and modelled data showing adverse effects in organisms at very low concentrations of DEHP support the very low PNEC that was calculated for DEHP. |
| Monitoring-based PECs for some phthalates exceed the water solubility limit of the substance. It would be useful to have some discussion regarding the validity of these measured values in the screening assessment. | The solubility of substances in a natural setting often differs from that measured under laboratory conditions. A measured environmental concentration value is considered acceptable if it falls within a factor of 10 of the laboratory-based value. This is the case for all phthalates, except DIUP, DTDP, and DUP. For these three phthalates, measured concentrations exceeded some modelled water solubility estimates but were within a factor of 10 for other estimates. The measured environmental concentrations for these phthalates are suitable for reporting because they are within the range of the extremely low solubility predicted for these substances. While not used in the derivation of risk quotients, these measured environmental concentrations were included in the analysis of cumulative risk |
| Capping the dilution factor (DF) at 10X to account for “point of release” or “near field” exposure provides an unnecessary degree of additional conservatism for free-swimming species. | The DF of a waterbody can vary by several orders of magnitude depending on flow events and velocities. Limiting the DF at 10 to better reflect conditions near the discharge point is based on the assumption that full dilution is not achieved immediately after the substance is released to a large waterbody. |
| Wording in the draft screening assessment conveys the impression that all the results in Table 8-5 are based on endocrine effects. | Wording in Table 8-5 in the screening assessment was adjusted to remove specific reference to endocrine effects. |
| Positive statements that endocrine effects are reported (e.g. Table 8-5) should be amended to clearly identify substances with a causally demonstrated endocrine Mode of Action (MOA) vs. those where endocrine effects have not been unequivocally demonstrated or have merely been inferred. |
The screening assessment was revised to clarify causally demonstrated vs. inferred endocrine MOA. |
| It is unclear if bioaccumulation factors (BAFs) used in the cumulative assessment approach were experimentally derived or mathematically modelled. If modelled, the model needs to be specified and metabolism accounted for. | When available, experimental BAFs were used to determine tissue residue values for individual phthalates in the cumulative risk assessment. Where experimental BAFs were not available, modelled BAFs, which included biotransformation, were derived using the BCFBAF (2010) program in Estimation Program Interface (EPI) Suite (c2000-2012). |
| The draft screening assessment states that endocrine effects were used to calculate the PNEC and risk quotient (RQ) for DEHP. | The screening assessment was revised to specify that the endpoint of impaired spermatogenesis was used to derive the PNEC and RQ for DEHP. |
8. Conclusion
| Summarized comment | Summarized response |
|---|---|
| The conclusion that medium-chain phthalates do not pose a potential risk to the health of Canadians at current levels of exposure requires further justification given that some of the HI are close to 1. | Using the most current information regarding the potential hazard and estimated levels of exposure to Canadians, the conservative lower tiered HI approach did not show a concern for the potential cumulative risk of medium-chain phthalates for the general Canadian population, specifically the more susceptible subpopulations (e.g. pregnant women, women of childbearing age, infants, and children) at current exposure levels. An HI value greater than 1 would indicate the need for further investigation or refinement. The HI values for the three subpopulations with the highest exposures were all below 1. Therefore, further refinement to a higher tiered assessment is not necessary based on current levels of exposure. Further, follow-up activities to track changes in exposure and/or commercial use patterns of the medium-chain phthalates are being proposed. |
| The screening assessment does not adequately consider the precautionary principle in its conclusion that the combined exposure of phthalates does not rise to the level necessary to restrict the majority of these chemicals from being used in personal care and other products. A growing body of research shows that phthalates harm human health and are especially harmful to children because their growing bodies are susceptible to phthalates’ interference with hormone signalling systems. | As required under CEPA, the Government of Canada has applied precaution and weight of evidence while characterizing risk for individual phthalates and in conducting the cumulative risk assessment. The cumulative risk assessment was conducted using a conservative, lower-tiered hazard index approach. Given the current levels of exposure to medium-chain phthalates, this cumulative risk assessment did not show concerns regarding potential cumulative risks for the general Canadian population, including susceptible subpopulations, such as pregnant women/women of childbearing age, infants, and children. Since the HI values for the three subpopulations with the highest estimated exposure levels are below one, further refinement to a higher tiered assessment is not necessary. |
| The screening assessment has re-assessed DEHP and now proposes that it meets Section 64(a) of CEPA (i.e. it is ecologically toxic). The proposed risk management is to achieve the lowest releases of DEHP to water. Any risk management consideration should first focus on closing the data gaps and then move to address releases from confirmed sources of DEHP to water. If additional measures are needed, then a phased risk management approach must be undertaken that considers the Principles to Inform the Chemical Management Plan Implementation as applicable to the Automotive Manufacturing Sector. | The conclusion for DEHP is based on both measured and modelled values. All potential sources of releases are considered when making risk management decisions. |
| The validity of the assessment conclusion should be reconsidered for a group of endocrine disrupting chemicals, for which very low exposure levels can have detrimental health outcomes for humans, depending on the time of exposure. | The Screening Assessment considered phthalates exposure for susceptible subpopulations, which include women of childbearing age, pregnant women, and infants. Exposure was estimated based on recent Canadian biomonitoring data, when available, and was compared to life-stage specific points of departure (including in the womb) which included endocrine-related effects, such as reproductive and developmental effects. For more information on considerations of endocrine-related effects in assessments conducted under the CMP, refer to the Risk Assessment Series Fact Sheet: Consideration of endocrine-related effects in risk assessment. |
| Limited analytical sensitivity may have resulted in misleading conclusions regarding human exposures to some phthalates measured with inadequate methods such as the Canadian Health Measures Survey (CHMS). Use of imprecise and inadequate analytical methods may undermine the effectiveness of any risk management program. | Analysis of phthalates for the CHMS is conducted by the Centre de Toxicologie du Québec (CTQ), a world leader in the development and application of analytical methods for human biomonitoring of chemicals. The analytical method employed for phthalate analysis is sensitive, and the detection limits for the CTQ method is much lower than those applied in other jurisdictions. |
| The scientific evidence presented in the screening assessment supports the overall conclusion. | Noted. |
| There is agreement with the conclusion that there is no concern for potential cumulative risk of medium-chain phthalates for the general Canadian population at current exposure levels. | Noted. |
9. Risk management
| Summarized comment | Summarized response |
|---|---|
| If the objective for future risk management measures is “to reduce the concentration of DEHP in the ambient aquatic environment to levels below the PNEC of 0.07 μg/L,” then additional steps need to be taken to assess the concentration and source of DEHP in the aquatic environment. | Continued monitoring of the DEHP in the ambient aquatic environment will take place in order to evaluate if risk management and environmental objectives are met. |
| If the final screening assessment concludes that B79P is toxic and the Government of Canada recommends risk management approaches that could impact the automotive manufacturing industry, then these activities should be coordinated with the United States due to the highly integrated nature of our sector. Considerable time will be needed to identify all uses of B79P in the industry. | Based on additional information provided, the assessment of B79P was updated and is no longer proposed toxic. As a result, risk management actions are no longer being considered for this substance. However, given that B79P has ecological and human health effects of concern, post assessment activities are being proposed to gather additional information and monitor compliance with existing requirements. |
| Chemicals contained within an electronic product do not pose an environmental or health risk under normal use of the product. Responsible management of electronic products at the end of their useful life is regulated in every jurisdiction across Canada. Electronic products are recycled, ensuring that the chemicals contained in the products pose no risk to the environment. To date, about a million tonnes of electronics have been diverted from landfill across Canada thus pre-empting possible damage to the environment from contaminated leachate. | CEPA factsheets recognize that electronic equipment may be hazardous when improperly discarded or recycled. The Government of Canada continues to work towards modernizing the management of hazardous wastes and recyclables by diverting waste toward environmentally sound recycling, minimizing hazardous waste generation, and promoting the use of greener technologies. |
| The Government of Canada should focus on educating vulnerable populations so they can reduce their exposure to phthalates before and during pregnancy, infancy, and childhood through reproductive years. | Health Canada published an educational content document on phthalates for the public (available online). Phthalates will also be included in Health Canada’s Healthy Homes Campaign to inform and educate the public about potentially harmful chemicals found in the home. |
| It would be more appropriate for Canada to propose aggressive actions to better protect vulnerable populations from these substances, with a view to phase out and initiate an eventual ban of these substances in consumer products. | Risk management actions are based on the most up to date scientific evidence and other relevant information available at the time of assessment. At the current levels of exposure, the conservative, lower-tiered HI approach did not show a concern for the potential cumulative risk of medium-chain phthalates for the general Canadian population, including susceptible subpopulations. The Government of Canada is also proactive in further protecting vulnerable populations by monitoring changes in use patterns and/or exposure to medium-chain phthalates. To determine if further investigation or action is required any new data, including data acquired by applying new or sensitive analytical methods may be considered. |
| The financial costs of human health and environmental effects associated with exposure to substances should be assessed and reported transparently. | Economic, social, health and environmental implications, are considered when developing risk management tools. Screening assessments are based on data and information regarding the environmental and health aspects associated with a substance. Economic and social implications are considered during development of risk management instruments. A cost-benefit analysis and regulatory impact assessment statement (RIAS) is developed and published with each proposed regulation. |
| The ongoing and possibly increased use of some phthalates warrants a more precautionary approach and a public health perspective when considering their inclusion in consumer products and medical devices. Phthalates should be removed from products directed at vulnerable populations, such as medical supplies, infant supplies and toys, personal care and cleaning supplies, and packaging, and eventually broadly phased out. The human health implications resulting from phthalate exposure during vulnerable periods in life suggest that the current approach proposed by the Government of Canada is not sufficiently precautionary. There is no safe exposure to phthalates for vulnerable populations. | The Government of Canada follows a risk-based approach for assessing and managing chemicals. The screening assessment acknowledges that while risk is low at current exposure levels for the cumulative risk of medium-chain phthalates, an increase in exposure levels could represent a potential risk to human health. Therefore, follow-up activities to track changes in exposure and/or commercial use patterns are being proposed for these substances. For a list of proposed activities, please see the Summary of Publications section, in the Follow-up Activities column. |
10. Alternatives and chemical substitution
| Summarized comment | Summarized response |
|---|---|
| Substitution of any of the phthalates in the draft screening assessment must be informed by present and potential future human exposure levels. Such research should include low and environmentally relevant doses, and transparent reporting of results. Scientific evidence should indicate that a new substance or replacement plasticizer, as well as all of its degradation products, is safe for human health and the environment, even at low exposure levels. Alternative materials (e.g. free of polyvinylchloride) that are inert and do not require dissolution of softeners (i.e. plasticizers) or other potential toxicants (i.e. stabilizers) should be a focus of research and used as preferred alternatives. | Since 1994, CEPA has required that new substances manufactured or imported into Canada above certain thresholds undergo government-led human health and environmental assessments. When a substance presents potential risks to the environment or human health, control measures may be applied before allowing it into the Canadian marketplace. A substance will be prohibited in Canada when it is determined that risks associated with exposure are too great and/or the substance cannot be sufficiently managed. The Government of Canada is also exploring ways to advance responsible replacement of chemicals of concern, including ways to apply informed substitution to support chemicals management (see Combined government discussion paper and science committee report on informed substitution). |
| Stronger risk management measures are needed for DEHP and other endocrine-disrupting phthalates to address exposures through dietary sources. | Although health risks from current dietary sources were not detected, additional activities are proposed to track changes in dietary exposure (e.g. TDS) and/or commercial use patterns for medium-chain phthalates. |
11. Consultation and stakeholder engagement
| Summarized comment | Summarized response |
|---|---|
| If it is determined that risk management is needed for any of the 28 phthalates considered in the draft screening assessment direct consultation with the affected stakeholders will be crucial. | Risk management scope documents for B79P and DEHP were released for public consultations along with the draft screening assessment. Due to the assessment conclusion, a risk management approach document for DEHP alone was developed and released for public consultation along with the screening assessment. Consultation with stakeholders is an essential part of the risk management process. The Government of Canada is committed to consulting extensively with all affected stakeholders when developing risk management measures. |
| Apply the latest, highest quality information and ensure full transparency on methods and assumptions. There are challenges with reapplying the cumulative methodology, and it may need to be done on a case-by-case basis. Effective stakeholder engagement and communications will be important. It would be helpful if Health Canada and Environment and Climate Change Canada (ECCC) were to share an updated version of the Organisation for Economic Co-operation and Development (OECD) paper on assessing combined exposures to chemicals for further Canadian stakeholder review and discussion. | The most recent and relevant data were considered in the final screening assessment. The Government of Canada is committed to maintaining open and transparent assessment processes. Consultation with stakeholders is an essential part of the risk management process. Draft assessments under the CMP are subject to a 60-day public comment period. All comments received are considered in finalizing the assessment report. The OECD Guidance Document on Considerations for Assessing the Risks of Combined Exposure to Multiple Chemicals was released on December 6, 2018 and is available online [PDF]. |
| It is important that the Government of Canada continue to accurately communicate to Canadians about the safe use of these substances. | Noted. The “What can Canadians do?” section of the Information Sheet on the Phthalate Substance Grouping provides information to the public on safe use. |
| There should be additional consultation on proposed follow up activities that will take place, including tracking and monitoring, to allow for appropriately targeted activities, and avoid unnecessary resource expenditure | The Government of Canada intends to consult with affected stakeholders should any proposed follow-up activities directly impact stakeholders, or should additional risk management measures be required. |
| Assistance is offered to work with the Government of Canada to address data gaps identified in the screening assessment and risk management documents. | Noted. |
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