|Uses||The conclusion that CHPD is not harmful is based on limited information on importation and future intended uses. This conclusion could encourage increased use of this substance.||Information on manufacture, import, and use is reported under the Section 71 survey and information from other years is also considered. Section 71 submissions did not anticipate increases in future uses of CHPD. All assessed substances are subject to further evaluation if relevant information is received that indicates further evaluation is warranted. CHPD will be considered for inclusion in the Domestic Substances List inventory update initiative.|
|The screening assessment does not represent an exhaustive or critical review of all available data. It also appears that the “weight of evidence” for decisions that may lead to eliminating substances in commerce is not consistent and should focus on toxicity and not exposure.||Greater certainty is provided in the Screening Assessment Report (SAR) based on re-analysis of new data provided for CHPD. Screening assessments consider the relevant data, and critically evaluate the key studies. The assessment presents the critical studies and lines of evidence pertinent to the assessment. Uncertainties in the assessment are noted.|
|Releases||The assessment does not provide enough information on the use of CHPD and sources of environmental releases to adequately assess ecosystem hazards, and potential exposure risks to human health.||Potential releases of CHPD were estimated at different life cycle stages for releases to water, air, and soil. This substance is mostly bound in products that are sent to landfills or incinerators for disposal. As such, potential for exposure and risk to ecosystems and humans have been adequately assessed.|
|Information verifying that CHPD is not released from landfills through leaching is insufficient. Quantities are not provided and amounts of the substance are referred to as percentages of an unknown total. Also, imported products containing CHPD are not considered in the assessment.||It has been clarified in the Screening Assessment Report (SAR) that CHPD is not released from landfills since they are required to have clay liners and leachate collection and / or treatment systems. Also if CHPD is released by accident it is absorbed and immobilized in surrounding soils, preventing release to water and air.|
|Environmental Fate||Long-Range Transport Potential (LRTP) was not considered.||Long-range atmospheric transport of CHPD is not expected based on its very low quantities released to the air.|
|Persistence and Bioaccumulation||CHPD is persistent and when released to the environment will accumulate within the food chain. Small amounts may harm organisms found in aquatic environments.||Evidence indicates that CHPD has a low bioaccumulation potential within food chains. Further analysis also shows that potential concentrations of CHPD in the environment are not high enough to harm aquatic life. The SAR was updated to reflect this information.|
|Should molecular characteristics be assigned high weighting, given that they must be “considered with care”?||Molecular characteristics are generally precise, while the interpretation of chemical properties is subjective. The molecular characteristic analysis on permeation of fish tissues indicates that there is no biomagnification of CHPD.|
|The decision that CHPD does not meet bioaccumulation criteria is based on one confidential fish study.||Companies submit confidential information in compliance with Section 313 of the CEPA 1999. Exact information remains confidential. However, both confidential and non-confidential information are given the same level of scrutiny. This ensures the reliability of confidential studies. Based on this analysis, it was determined that CHPD does not meet criteria for biomagnification.|
|Monitoring and Exposure||The assessment indicates that exposure to CHPD is “chronic”. This conflicts with the Appendix where CHPD exposure is listed as “acute”.||Exposure to CHPD is “chronic”. The Appendix has been updated.|
|The acute toxicity value for daphnia was used in place of the toxicity value for algae in Table 7a.||The table was updated to reflect the toxicity data for algae.|
|In the absence of a detection limit, results of this program cannot be interpreted.||The limit of detection (LOD) has been developed and is 10 times lower then the predicted no effect concentration (PNEC). This LOD along with a methodology to measure CHPD in water was added to the SAR.|
|Cumulative and synergistic effects should be addressed in the draft assessment as an aspect of exposure and risk, given that exposures occur from multiple sources and in the context of exposure to other potentially toxic substances.||Consideration of cumulative and synergistic effects is not precluded from a screening assessment. However, in order to be considered, sufficient information to undertake such analyses would be required.|
|Ecological Toxicity||Toxicity data for aquatic arthropods should not be used to extrapolate risk quotients for sediment/soil dwelling arthropods, because CHPD concentrations can build up in soils/sediments over time.||The SAR for CHPD considers that exposure levels could increase in soil and sediment due to accumulations over time and the persistence of the substance.|
|The assessment of CHPD is not supported by available data. In particular, data was not available on surface water concentrations; predicted effects for aquatic and terrestrial life; and measurement of the tropic magnification factor.||A modeled realistic worst-case aquatic concentration was determined and used in the assessment and was thought to be the maximum aquatic concentration likely to be found. The trophic transfer is estimated to be low given the result of the fish dietary bioaccumulation study.|
|Human Health Effects|
The non-toxic conclusion should be changed because First Nations and Inuit are exposed to higher concentrations of harmful substances compared to other Canadian populations.
It is recommended that consideration be given to vulnerable populations, including children and aboriginal communities.
The Challenge screening assessments are based on considerations of the available data. Various conservative exposure scenarios are considered for both the general and vulnerable populations in Canada and incorporate specific exposure estimates for Canadians of different ages. However, if additional or new information suggests that a specific sub-population is vulnerable, this information would be considered in the assessment.
CHPD is not likely to accumulate significantly or biomagnify in trophic food chains, consequently exposure of the Northern community population or other vulnerable populations is considered to be low.
|The assessment does not include an analysis of the potential modes of action of CHPD nor does it take into account possible differences in sensitivity between humans and between other non-human species.||Available information indicated that CHPD does not have a high hazard potential. No information was available to conduct an analysis of the potential modes of action of CHPD or differences in sensitivity between humans. As to other non-human species, data were available for three of them.|
|Uncertainties||The screening assessment does not represent an exhaustive or critical review of all available data. It also appears that the “weight of evidence” for decisions that may lead to eliminating substances in commerce is not consistent and should focus on toxicity and not amount of exposure.||Greater certainty is provided in the SAR based on an updated analysis of new data provided for CHPD. Screening assessments consider the relevant data, and critically evaluate the key studies. The assessment presents the critical studies and lines of evidence pertinent to the assessment. Uncertainties in the assessment are noted.|
|There is not enough evidence to conclude that CHPD is not harmful to environmental and human health.||The evidence is considered reliable and relevant to support the conclusion of not toxic under CEPA section 64. If new information is submitted, the conclusion could be reconsidered in the final screening assessment.|
|CHPD is a persistent substance that is used as a dye in many plastics, polystyrene, and acrylics. Assessment is based on unknown amount of CHPD imported in products and use patterns can change from year to year. The conclusion of non-CEPA toxic may result in an increase in use. Assumptions that CHPD is not harmful are based on limited information from over four years ago.|
The Government of Canada collects information through surveys conducted under section 71 of CEPA 1999. While information on products and manufactured items may be provided in the submissions, data gaps associated with such quantity is recognized as an uncertainty in the screening assessment.
Releases of CHPD in imported products would occur after disposal of products. As indicated in the SAR, few releases are expected from waste disposal sites.
There was no submission to indicate potential increase in CHPD activity in the future.