Summary of Public Comments Received on the Draft Screening Assessment Reports for Batch 5 for Disperse Orange 30 (CAS 5261-31-4), Disperse Blue 79 (CAS 12239-34-8), ANAM (CAS 16421-40-2), AADM (CAS 16421-41-3), Disperse Brown 1:1 (CAS 17464-91-4), Disperse Brown 1 (CAS 23355-64-8), Disperse Red 167 (CAS 26850-12-4), BANAP (CAS 29765-00-2), BDAP (CAS 52697-38-8), Disperse Orange 61 (CAS 55281-26-0), EDD (CAS 55619-18-6), DNAN (CAS 72927-94-7)
Comments on the draft screening assessment reports for Disperse Orange 30, Disperse Blue 79, ANAM, AADM, Disperse Brown 1:1, Disperse Brown 1, Disperse Red 167, BANAP, BDAP, Disperse Orange 61, EDD, DNAN substances included in Batch 5 of substances to be addressed as part of the Chemicals Management Plan Challenge were provided by Learning Disability Association of Canada and Chemical Sensitivities Manitoba, and the Canadian Environmental Law Association.
A summary of comments and responses is included below, organized by topic:
- Risk Assessment
| Topic | Comment | Response |
|---|---|---|
| Risk Assessment | There is concern that all of the dyes lack basic toxicity data. If these substances are used as analogues, how can these be considered “robust models?” | There is limited toxicity data for these substances. However data available for several disperse dye analogues consistently indicates that disperse dyes have only low to moderate potential to cause toxicity. Furthermore, their low solubilities, relatively high molecular weights and their solid particulate structures add to the weight of evidence that these dyes would not be sufficiently bioavailable to cause significant toxicity. As stated in the screening assessment reports, aquatic toxicity predictions have been obtained from the various QSAR models considered for each dye and their analogues. However, these QSAR ecotoxicity predictions were not considered reliable because of the potential error associated with input parameters and the unique nature of disperse dyes specifically, structural and/or physico-chemical properties which fall outside of the models’ domain of applicability. Therefore, the results from the QSAR models were not used in concluding on the aquatic toxicity of the dyes. |
A cumulative assessment is recommended based on similar use patterns
|
The individual screening assessments did not present a cumulative assessment. However, a cumulative scenario was run with the Industrial Generic Exposure Tool – Aquatic (IGETA) assuming one facility (which reported import and/or use of most of the Batch 5 dyes through the s.71 notice) used all of the reported amounts at the same time, and released them to the same sewage treatment plant (STP). The result of this very conservative approach is a risk quotient which is still less than one. [Environment Canada. 2009. IGETA report: Batch 5 monoazo textile dyes. Unpublished report. Gatineau (QC): Environment Canada, Existing Substances Division.May 20, 2009.] Note that 60% removal from sewage treatment is assumed in this cumulative assessment, although the individual SARs assumed no sewage treatment. The 60% removal rate is appropriate since the municipal STP to which all releases were assumed to be discharged has secondary treatment. | |
| There are concerns about the use of analogues for these assessments. | The use of analogue toxicity and bioaccumulation data in these assessments is considered to be reasonable. Although there is some uncertainty associated with the use of analogue data, other lines of evidence were also considered (including their particulate form, relatively large molecular size and low solubility) which further supported the conclusion that these substances have relatively low potential for bioaccumulation and toxicity. |