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Substitution of Benzotriazole UV Absorbers in Plastics

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Presented at the SPE Thermoplastic Elastomers TOPCON, September 2018. This paper discusses how UV-328 and other benzotriazoles came to be classified as SVHC under REACH, and identifies potentially safer substitutes for additive users based on the results of a hazard assessment.

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Substitution of Benzotriazole UV Absorbers in Plastics

  1. 1. © 2018 James H. Botkin dba BotkinChemie Page 1 of 19 Substitution of Benzotriazole UV Absorbers in Plastics James H. Botkin dba BotkinChemie, Madison, NH Presented at the SPE Thermoplastic Elastomers Conference, September 2018, Akron, OH Abstract Benzotriazole UV absorbers such as UV-328 have been extensively used as light stabilizers in plastics and coatings for many years. However, increased regulatory compliance burdens associated with designation of some products (including UV-328) as Substances of Very High Concern (SVHC) in Europe are driving additive users around the world to phase-out their use by substitution with safer alternatives. This paper discusses how UV-328 and other benzotriazoles came to be classified as SVHC under REACH, and identifies potentially safer substitutes for additive users based on the results of a hazard assessment. Introduction Benzotriazole UV absorbers are widely used as light stabilizers in plastics and coatings, functioning by competitive absorption of harmful UV radiation. These useful additives feature broad absorbance coverage over both the UV-A (λ = 315-400 nm) and UV-B (λ = 280-315 nm) regions, minimal absorbance of visible light (λ > 400 nm), and excellent long-term photo- stability. Benzotriazoles represent a versatile chemical platform in that products having a wide range of secondary properties (physical form, melting point, volatility) have been developed and are commercially available. However, new regulatory developments in Europe are creating considerable pressure for phase-out or substitution of some products, including the widely used UV-328. This paper seeks to address the following questions associated with the regulation and substitution of benzotriazole UV absorbers: 1. What exactly is happening and what are the implications? 2. What products are affected by regulatory developments? 3. Why are some products being regulated? 4. Will other products be regulated in the future? 5. How can better substitutes be identified? 6. How to formulate in new applications to minimize risks? Affected Products, Status, & Implications The subject products of this paper are ten different commercially available, solid benzotriazole UV absorbers that have been historically been used as light stabilizers in plastics and coatings applications. The common names (based on Ciba product nomenclature), chemical names, CAS numbers, and chemical structures are provided in Table 1. In 2014-2015, four of these substances (UV-320, UV-327, UV-328, and UV-350) were placed on the Candidate List of Substances of Very High Concern (SVHC) by the European Chemicals Agency (ECHA).[1] The basis for this development was the identification of these substances as Persistent, Bioaccumulative, and Toxic (PBT) and/or very Persistent and very Bioaccumulative (vPvB). Under the REACH regulation, there is a duty to communicate information on these substances and other SVHC present above a cut-off concentration (0.1% by weight) in articles, preparations, and chemical products.[2] Producers and importers of
  2. 2. © 2018 James H. Botkin dba BotkinChemie Page 2 of 19 articles containing SVHC may also need to submit a notification to ECHA. The increased regulatory burden associated with the designation of these substances as SVHC has pressured additive users to begin phasing out their use by substitution with functionally equivalent alternatives. In February 2018, ECHA recommended addition of UV-328, UV-320, UV-327, and UV-350 to the REACH Annex XIV List (“Authorisation List”).[3] This represents a more serious regulatory development. Once added to the Authorisation List, companies using these substances would be required to apply for authorization with ECHA in order to continue existing uses. Substances on the Authorisation List may also be subject to a sunset date, after which they cannot be used without authorization. This development has placed additional pressure on additive users worldwide to phase-out the use of these products. The issue is particularly acute for UV-328, which is a high volume product widely used in the plastics and coatings industries. Other benzotriazole UV absorbers are also under scrutiny in Europe due to PBT concerns. In 2014-2015, informal evaluations of five other benzotriazole UV absorbers (UV-P, UV-234, UV-326, UV-329, and UV-928) were initiated under ECHA’s Public Activities Coordination Tool- Risk Management Option Analysis (PACT-RMOA) program.[4] As of August 2018, assessments of these substances are still under development. ECHA cautions that inclusion of a substance in the PACT program only means that a Member State or ECHA is examining it, not that it actually has PBT properties or that there is need for regulatory risk management actions.[5] For any substance being assessed, the outcome may well be that it is not found to have PBT properties based on available data. However, the fact that these potential alternative products are being scrutinized makes it more difficult for additive formulators to identify appropriate alternatives to UV-328. In Japan, UV-320 came under regulation as a Class I Specified Chemical Substance in 2007 under the Chemical Substances Control Law (CSCL).[6] Class I Specified Substances are regulated based on being found to be persistent, highly bioaccumulative and posing a risk of long-term toxicity to humans or animals. Under the CSCL, prior permission is required for manufacture and/or import, which constitutes a virtual prohibition except for uses designated as essential. UV-327 and UV-350 are regulated under the CSCL as Monitoring Chemical Substances based on concerns regarding persistence and bioaccumulation.[7] For these substances, annual reporting is required if volumes of manufacturing or import are greater than 1 ton per year. The authority may also order manufacturers and importers to investigate long- term toxicity for humans or animals. None of the other benzotriazole UV absorbers listed in Table 1, including UV-328, are subject to restrictions in Japan under CSCL. In the USA, no assessments of any of the benzotriazole UV absorbers listed in Table 1 have been initiated to date by the EPA under the Toxic Substances Control Act (TSCA) Work Plan [8- 9] or under the amended TSCA.[10] However, UV-320, UV-328, and UV-329 have been listed on chemicals of concern lists at the State level. In Canada, a screening assessment was completed by Environment and Climate Change Canada and Health Canada for UV-328 in 2016 with no further action recommended.[11] Several other substances listed in Table 1 (UV-234, UV-326, UV-329, and UV-350) met the criteria for screening under the Canadian Environmental Protection Act (CEPA) and may possibly be subject to screening assessments in the future. While no regulatory actions on UV-328 are pending in the USA, Japan, or Canada, the importance of Europe in global supply chains continues to provide incentive to additive formulators around the world to replace it with safer alternatives. As part of the search for
  3. 3. © 2018 James H. Botkin dba BotkinChemie Page 3 of 19 alternatives, it’s helpful to understand the reasons behind the regulatory issues associated with UV-328, UV-327, UV-320, and UV-350. Rationale for Regulation: Persistence, Bioaccumulation, & Toxicity As described in the previous section, benzotriazoles are subject to regulatory scrutiny based on concerns over their persistence, bioaccumulation, and toxicity. Chemicals known to be persistent, bioaccumulative, and toxic (PBT); or very persistent and very bioaccumulative (vPvB) are of particular concern for regulators since they can remain in the environment for a long time and can bioaccumulate in animal tissues. Over time, releases of these chemicals have the potential to accumulate to higher levels and may cause significant adverse impacts on human health and/or the environment. Persistence is defined as resistance of a chemical substance to environmental degradation through natural chemical, biological, and photolytic processes. This can be inferred through monitoring studies in water, soils, and sediments. Benzotriazoles were first recognized as persistent based on monitoring studies conducted on sediments from locations near a former production site for UV-327 and UV-328 in Rhode Island.[12] Regulators often assess the persistence of a chemical substance by its degradation half-life times (T1/2) in water, sediment, and soil, which can be determined by laboratory tests or the use of molecular modeling software. The criteria for designation of substances as persistent (P) and very persistent (vP) are set forth in Annex XIII of the REACH regulation.[13] In general, chemicals meet the criteria for vP under REACH if their T1/2 in water is greater than 60 days and/or greater than 180 days in soil or sediment. In the USA, the EPA has adopted similar criteria, and a chemical is characterized as vP if its T1/2 in water, soil, or sediment is greater than 6 months.[14] Based on information contained in the REACH dossiers [15-22] and the Candidate List documentation [1] all of the benzotriazole UV absorbers listed in Table 1 are considered to meet the criteria for vP under the REACH criteria, and would probably be characterized as vP under the EPA criteria as well. Bioaccumulation is defined as the tendency of a chemical substance to accumulate in living organisms. This can be inferred through monitoring studies in wildlife or in humans. Benzotriazole UV absorbers were first detected in monitoring studies conducted with marine organisms in Japan,[23] and benzotriazole UV absorbers have since been found in monitoring studies conducted with marine life in other parts of the world.[24-27] Regulators usually assess then tendency of a substance to bioaccumulate using Bioconcentration Factor (BCF) or Bioaccumulation Factor (BAF) values, which are determined by laboratory tests or through the use of molecular modeling software. The criteria for designation of substances as Bioaccumulative (B) and Very Bioaccumulative (vB) are set forth in Annex XIII of the REACH regulation.[13] In general, substances having a BCF value greater than 2,000 are considered to be B, and those having a BCF value greater than 5,000 are considered to be vB. In the USA, the EPA considers a substance to be B if its BCF or BAF value is greater than or equal to 1,000, and vB if its BCF or BAF value is greater than or equal to 5,000. Based on BCF data contained in the REACH dossiers [18] and candidate list documentation [1], UV-320, UV-327, UV-328, and UV-350 all meet the REACH and EPA criteria for vB. Additionally, the BCF values for UV-234 [16] and UV-928 [22] meet the EPA criteria for B (although they do not meet the REACH criteria for B). The remaining substances (UV-P, UV- 326, UV-329, and UV-360) are not considered to be B under either REACH or EPA criteria based on BCF values less than 1,000.[15,17,19-21]
  4. 4. © 2018 James H. Botkin dba BotkinChemie Page 4 of 19 Toxicity is defined as the degree to which a substance can damage an organism. Toxicity and eco-toxicity are assessed using test methods based on the UN Globally Harmonized System (GHS) of hazard classification. The criteria for designation of a substance as toxic (T) are set forth in Annex XIII of the REACH regulation. Benzotriazoles present varying degrees of chronic toxicity and chronic aquatic toxicity. Based on data contained in the REACH dossier [18] and candidate list documentation [1], UV-320 and UV-328 are considered T under REACH criteria. The remaining substances (UV-P, UV-234, UV-326, UV-327, UV-329, UV-350, UV-360, and UV-928) do not meet the REACH criteria for T based on candidate list documentation [1[ or the REACH dossiers.[15,17,19-21] As defined under the REACH regulation, UV-320, UV-327, UV-328, and UV-350 are all considered to be PBT and/or vPvB substances, and this can be regarded as the root cause for the current regulatory restrictions. The alternative products do not meet the criteria for either PBT or vPvB based on available data, but all can be regarded as very Persistent (vP) and present varying degrees of bioaccumulation and toxicity. However, as the criteria for bioaccumulation and toxicity used by regulators may be subject to change, additive formulators may desire to lower the risk of making a regrettable substitution by selecting alternatives based on their bioaccumulation and toxicity characteristics, for example through a hazard assessment. Identifying Safer Alternatives Using Hazard Assessments Hazard assessments represent part of a larger alternatives assessment process, which addresses other factors such as technical performance, cost, commercial availability, and environmental life cycle attributes. Through the use of hazard assessments, users of chemicals can select safer alternatives and avoid replacing one hazardous substance with another. In the case of the benzotriazole UV absorbers, a hazard assessment is intended to support informed decision-making by additive formulators and end users by providing a basis to rank the attractiveness of alternatives based on their inherent hazard characteristics. Some hazard assessment methods utilize numerical ratings or benchmarks in order to facilitate comparisons between different alternatives. The best methods are based on criteria developed by or consistent with those used by regulatory agencies for evaluating chemical hazards, for example the UN Globally Harmonized System of Classification and Labeling of Chemicals (GHS) and the EPA Design for the Environment Program Alternatives Assessment Criteria for Hazard Evaluation (DfE). Numerous hazard assessment methods have been developed. Examples include: • GreenScreen® for Safer Chemicals (“GreenScreen® ”) • GreenScreen List Translator™ • Quick Chemical Assessment Tool (QCAT) • EPA TSCA Work Plan Chemical Scoring GreenScreen® is a hazard assessment method developed by the NGO Clean Production Action, that is designed for use by businesses, government agencies, and certification bodies to identify chemicals of high concern and safer alternatives.[28-29] This comprehensive method expands on the GHS and DfE methods, with a full GreenScreen® assessment covering human health and environmental effects data for a chemical substance based on 18 different hazard endpoints (carcinogenicity, mutagenicity/genotoxicity, reproductive toxicity, developmental toxicity, endocrine activity, acute human toxicity, respiratory sensitization, skin irritation/corrosivity, eye irritation/corrosivity, acute aquatic toxicity, chronic aquatic toxicity, acute and chronic neurotoxicity, skin sensitization, persistence, bioaccumulation, physical reactivity,
  5. 5. © 2018 James H. Botkin dba BotkinChemie Page 5 of 19 and flammability). Based on the results of the assessment, chemical substances are assigned one of five benchmark scores: Benchmark-1 (avoid – chemical of high concern), Benchmark-2 (use but search for safer substitutes), Benchmark-3 (use but still opportunity for improvement), Benchmark-4 (prefer – safer chemical), or Benchmark U (not classifiable due to lack of data). The benchmark scoring makes the comparison of the hazards associated with different alternatives a straightforward exercise. Use of the GreenScreen® method would provide the most authoritative differentiation between the benzotriazole UV absorbers under consideration. However, due to its comprehensive nature, GreenScreen® assessments are inherently time consuming, and specialized training is recommended for personnel prior to conducting assessments. For this reason, simpler methods may be appropriate for a preliminary screening. The QCAT is a simplified hazard assessment method developed by the Washington State Department of Ecology with the support of Clean Production Action.[30] This method utilizes a smaller number of hazard endpoints (carcinogenicity, mutagenicity/genotoxicity, reproductive toxicity, developmental toxicity, endocrine activity, acute mammalian toxicity, acute aquatic toxicity, persistence, and bioaccumulation) and data sources than GreenScreen® to reduce the number data sources and time required to complete an assessment. Based on the results of the assessment, chemical substances are assigned one of four grades: A (high concern, avoid), B (moderate concern, use but search for safer alternatives), C (slight concern, improvement possible), or D (few concerns, preferable). This method is recommended for use to screen chemicals to determine whether a more in-depth assessment such as GreenScreen® is necessary. In the case of the benzotriazole UV absorbers, the downside of this method is that it does not cover known hazards such as chronic toxicity and chronic aquatic toxicity. The GreenScreen List Translator™ screening tool developed for the rapid identification of chemicals of high concern.[31] The method scores chemical substances based on information from hazard lists developed by authoritative scientific bodies around the world. The results are used to assign one of three List Translator scores: LT-1 (indicating the presence of a chemical on at least one authoritative hazard list expected to result in a Benchmark-1 score if further assessed with GreenScreen® ), LT-P1 (indicating presence of a chemical on at least one hazard list that may possibly result in a Benchmark-1 score upon further assessment with GreenScreen® ), or LT-UNK (indicating that the chemical is present on one or more lists but does not meet any of the criteria to assign an LT-1 or LT-P1 score). If no information is found for a chemical in any of the hazard lists, the substance is assigned a score of NoGSLT. GreenScreen List Translator™ scores can be determined easily and quickly using online services such as the Pharos Chemical and Material Library from the Healthy Building Network NGO.[32} While the method is suitable for the identification of chemicals of high concern, more comprehensive methods such as GreenScreen® are more appropriate for use in the identification of safer alternatives. The TSCA Work Plan Chemical Scoring method is used by the EPA to identify potential candidate chemicals for assessment under TSCA.[33] Chemicals are evaluated and given a score based on three characteristics: Hazard, Exposure, and potential for Persistence and Bioaccumulation. The Hazard and Persistence/Bioaccumulation Scores are derived from the EPA DfE criteria based on 12 different endpoints (acute toxicity, carcinogenicity, mutagenicity/ genotoxicity, reproductive toxicity, developmental toxicity, neurotoxicity, chronic toxicity, respiratory sensitization, acute aquatic toxicity, chronic aquatic toxicity). While this screening process is intended mainly to support initial decisions by the EPA to determine the relative priority of chemicals for further assessments, the Hazard and Persistence/Bioaccumulation Scores are suitable for use as the basis for a simplified hazard assessment to identify chemicals
  6. 6. © 2018 James H. Botkin dba BotkinChemie Page 6 of 19 of concern and make a preliminary screening of alternatives. Note that the Exposure Score relates to risks rather than the inherent hazards of a chemical substance, and therefore is not appropriate for inclusion in a hazard assessment. Hazard Assessment Screening of Benzotriazole UV Absorbers A modified version of the EPA’s TSCA Work Plan Chemical Scoring method was used to make a preliminary assessment of six different benzotriazole UV absorbers (UV-P, UV-234, UV- 326, UV-329, UV-360, and UV-928) as alternatives to UV-328. The method criteria [33] were applied using data and interpretations from the EU REACH dossiers [15-22] to obtain the Hazard and Persistence/Bioaccumulation scores. The alternatives were ranked based on the Total Score, which was defined as the sum of the Hazard and Persistence/Bioaccumulation Scores. Hazard Scores were assigned for UV-328 and the alternatives based on 10 different toxicological and eco-toxicological endpoints. Consistent with the TSCA Work Plan Chemical Scoring methodology, the Hazard Score for each substance was assigned based the highest hazard score from any individual hazard endpoint, and each substance was ranked as 3 (high), 2 (moderate), or 1 (low) for hazard. The scores for the reproductive toxicity, developmental toxicity, and chronic toxicity endpoints were based on applying the scoring criteria to the No Observed Adverse Effect Level (NOAEL) or No Observed Effect Level (NOEL) data rather than the Lowest Observed Adverse Effect Level (LOAEL) or Lowest Observed Effect Level (LOEL) data. For hazard endpoints where data from multiple studies were available, the hazard score was based on the data giving the highest possible score. The only exception to this rule was that data with a reliability score of 3 (not reliable) were deemed to be unreliable and not used to determine the hazard score for that particular endpoint. The raw hazard data for the individual endpoints are summarized in Tables 3-7. No data were available for any of the benzotriazoles for neurotoxicity or respiratory sensitization and therefore no scores could be assigned for those hazard categories. The Hazard Scores for UV-328 and the alternatives are described below and summarized in Table 2: • UV-328 was assigned a Hazard Score of 3 (high) based on chronic toxicity (Table 6). • UV-P was assigned a Hazard Score of 3 (high) based on chronic aquatic toxicity (Table 7). • UV-234 was assigned a Hazard Score of 2 (medium) based on chronic toxicity (Table 6). • UV-329 was assigned a Hazard Score of 2 (medium) based on chronic toxicity (Table 6). The score was deemed to be of low confidence based on the use of structural analog data for the chronic toxicity endpoint. • UV-326, UV-360, and UV-928 were assigned Hazard Scores of 1 (low). The Hazard Score for UV-928 was deemed to be of low confidence based on the use of structural analog data for some of the hazard endpoints. Bioaccumulation (B) Scores on a scale of 1 (low) to 3 (high) were assigned using experimental BCF values from the REACH dossiers. The bioaccumulation data for each substance and the corresponding B Scores are described below and are summarized in Table 8: • UV-328 was assigned a Bioaccumulation Score of 3 (high) based on a BCF value of 5,580. • UV-P was assigned a B Score of 1 (low) based on a BCF value of 494. • UV-234 was assigned a B Score of 2 (medium) based on a BCF value of 1,286.
  7. 7. © 2018 James H. Botkin dba BotkinChemie Page 7 of 19 • UV-326 was assigned a B Score of 1 (low) based on a BCF value of 895. • UV-329 was assigned a B Score of 1 (low) based on a BCF value of 461. • UV-360 was assigned a B Score of 1 (low) based on a BCF value of 1.5. • UV-928 was assigned a B Score of 2 (medium) based on a BCF value of 1,286. The score was deemed to be of low confidence based on the use of structural analog BCF data. All of the benzotriazoles were assumed to be very persistent and assigned Persistence (P) Scores of 3 (high). The B and P Scores were normalized according to the TSCA Work Plan Chemical Scoring method to give a consolidated Persistence/Bioaccumulation (PB) Score on a scale of 1 (low) to 3 (high). The normalized PB Scores for each substance are described below and are summarized in Table 8: • UV-328, UV-234, and UV-928 were assigned normalized PB Scores of 3 (high). The PB Score for UV-928 was deemed to be of low confidence based on the use of structural analog data to assign the B score. • UV-P, UV-326, UV-329, and UV-360 were assigned normalized PB Scores of 2 (medium). A Total Score for each substance was determined from the sum of PB and T Scores on a scale of 2 (low) to 6 (high). The Total Scores for each substance are described below and are summarized in Table 8: • UV-328 was assigned a Total Score of 6 (high). • UV-P and UV-234 were assigned Total Scores of 5 (medium-high). • UV-329 and UV-928 were assigned Total Scores of 4 (medium). The Total Scores for both substances were deemed to be of low confidence based on low confidence of the Hazard Score and/or PB Score. • UV-326 and UV-360 were assigned Total Scores of 3 (medium-low). Based on the Total Scores, the most preferred alternatives to UV-328 include UV-326, UV- 329, UV-360, and UV-928. UV-234 and UV-P appear to be less attractive alternatives based on their higher Total Scores. More comprehensive hazard assessments of UV-P and UV-234 (for example using the GreenScreen® method) would be helpful to better understand their inherent hazards and their suitability for use as alternatives to UV-328. Conclusions The benzotriazole UV absorbers UV-320, UV-327, UV-328, and UV-350 are facing significant pressures for phase-out due to regulatory developments in Europe. These substances were added to the Candidate List of Substances of Very High Concern (SVHC) in 2014 and were recommended for addition to the REACH Annex XIV List (the “Authorisation List”) in 2018. The basis for regulation is the identification of these substances as Persistent, Bioaccumulative, and Toxic (PBT) and/or Very Persistent and Very Bioaccumulative (vPvB) according to the criteria set forth in Annex XIII of the REACH regulation. The issue is particularly acute for UV-328, which is a high volume product widely used in plastics and coatings. Possible alternatives to UV-320, UV-327, UV-328, and UV-350 include UV-P, UV-234, UV- 326, UV-329, UV-360, and UV-928. None of the alternatives meet the criteria for regulation as PBT or vPvB chemicals set out in REACH Annex XIII based on data currently available in the REACH dossiers. Hazard assessments can help additive users to identify chemicals of concern and safer alternatives. The hazards of the alternatives relative to UV-328 were assessed using a modified
  8. 8. © 2018 James H. Botkin dba BotkinChemie Page 8 of 19 version of the EPA’s TSCA Work Plan Chemical Scoring method. Based on the results of the hazard assessment, the most attractive alternatives include UV-326, UV-329, UV-360, and UV- 928. However, it should be cautioned that some of the data used to assign scores to UV-329 and UV-928 were deemed to be of low confidence. Less desirable alternatives based on the results of the hazard assessment include UV-P and UV-234. More comprehensive assessments of UV-P and UV-234 (for example using the GreenScreen® method) would be helpful to better understand the inherent hazards of these products and their suitability for use as alternatives to UV-328. It should be noted that testing of the benzotriazoles is ongoing, and hazard classifications are subject to change based on new data. Hazard assessments are suitable for use to identify other chemicals of concern (such as flame retardants and plasticizers) and safer alternatives. The GreenScreen List Translator™ is an excellent starting point for additive users based on its speed and simplicity. In today’s regulatory environment, assessing hazards is as important as assessing performance, cost, and commercial availability, and should be a part of the component selection process for additive users. Acknowledgements Helpful advice and comments from Dr. Shari Franjevic of Clean Production Action are gratefully acknowledged. Disclaimer Although the information and recommendations set forth herein (hereinafter "information") are presented in good faith and believed to be correct as of the date hereof, BotkinChemie makes no representation as to the completeness or accuracy thereof. Information is supplied upon the condition that persons receiving it will make their own determinations as to its suitability for their purpose prior to its use. In no event will BotkinChemie be responsible for damages of any nature whatsoever resulting from the use of or reliance upon information. No representations or warranties either expressed or implied, or merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information for any substance to which information refers. No statements herein are to be construed as inducements to infringe any valid patent. References 1. European Chemicals Agency, “Candidate List of substances of very high concern for Authorisation”, https://www.echa.europa.eu/candidate-list-table. 2. European Chemicals Agency, “Summary of obligations resulting from inclusion of SVHCS in the Candidate List”, https://www.echa.europa.eu/candidate-list-obligations. 3. European Chemicals Agency, “Submitted recommendations”, https://www.echa.europa.eu/previous-recommendations. 4. European Chemicals Agency, “PACT – RMOA and hazard assessment activities”, https://www.echa.europa.eu/pact. 5. European Chemicals Agency, “Status and Purpose of PACT”, https://www.echa.europa.eu/status-and-purpose.
  9. 9. © 2018 James H. Botkin dba BotkinChemie Page 9 of 19 6. National Institute of Technology and Evaluation, “Japan CSCL: Class I Specified Chemical Substances”, https://www.nite.go.jp/en/chem/chrip/chrip_search/intSrhSpcLst?_e_trans=&slScNm=RJ_01 _001. 7. National Institute of Technology and Evaluation, “Japan CSCL: Monitoring Chemical Substances”, https://www.nite.go.jp/en/chem/chrip/chrip_search/intSrhSpcLst?_e_trans=&slScNm=RJ_01 _010. 8. U.S. Environmental Protection Agency, “TSCA Work Plan Chemicals”, June 2012, https://www.epa.gov/sites/production/files/2014- 02/documents/work_plan_chemicals_web_final.pdf. 9. U.S. Environmental Protection Agency, “TSCA Work Plan for Chemical Assessments: 2014 Update”, October 2014, https://www.epa.gov/sites/production/files/2015- 01/documents/tsca_work_plan_chemicals_2014_update-final.pdf. 10. Federal Register of July 7, 2017, pp. 31592-31593, Docket ID EPA-HQ-OPPT-2017-0327, https://www.regulations.gov/document?D=EPA-HQ-OPPT-2017-0327-0001. 11. Environment and Climate Change Canada, Health Canada, “Screening Assessment Report on Phenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1,1- dimethylpropyl)- (BDTP) Chemical Abstracts Service Registry Number 25973-55-1”, May 2016, http://publications.gc.ca/collections/collection_2016/eccc/En14-236-2015-eng.pdf. 12. European Chemicals Agency, “Annex XV report; Proposal for Identification of a Substance of Very High Concern on the Basis of the Criteria Set Out in REACH Article 57; Substance Name: 2,4-Di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol (UV-327); EC Number: 223-383- 8; CAS Number: 3864-99-1”, August 3, 2015, pp. 33-42, https://www.echa.europa.eu/documents/10162/755b24e4-40dc-455b-afc0-b5e4e9045701. 13. Annex XIII: Criteria for the Identification of Persistent, Bioaccumulative, and Toxic Substances, and Very Persistent and Very Bioaccumulative Substances; Regulation (EC) No. 1907/2006 of the European Parliament and of the Council of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC. https://eur-lex.europa.eu/legal- content/EN/TXT/?uri=CELEX%3A02006R1907-20140410. 14. Office of Pollution Protection and Toxics, US Environmental Protection Agency, “Use Information for Persistent, Bioaccumulative, and Toxic Chemicals under TSCA Section 6(h)”, webinar, September 7, 2017, https://www.epa.gov/assessing-and-managing-chemicals- under-tsca/presentation-september-7-2017-webinar-use-information. 15. European Chemicals Agency, Registration Dossier for 2-(2H-benzotriazol-2-yl)-p-cresol, https://www.echa.europa.eu/web/guest/registration-dossier/-/registered-dossier/13300. 16. European Chemicals Agency, Registration Dossier for 2-(2H-benzotriazol-2-yl)-4,6-bis(1- methyl-1-phenylethyl)phenol, https://www.echa.europa.eu/web/guest/registration-dossier/- /registered-dossier/11135. 17. European Chemicals Agency, Registration Dossier for Bumetrizole, https://www.echa.europa.eu/web/guest/registration-dossier/-/registered-dossier/5785.
  10. 10. © 2018 James H. Botkin dba BotkinChemie Page 10 of 19 18. European Chemicals Agency, Registration Dossier for 2-(2H-benzotriazol-2-yl)-4,6- ditertpentylphenol, https://www.echa.europa.eu/web/guest/registration-dossier/-/registered- dossier/5280. 19. European Chemicals Agency, Registration Dossier for 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3- tetramethylbutyl)phenol, https://www.echa.europa.eu/web/guest/registration-dossier/- /registered-dossier/13220. 20. European Chemicals Agency, Registration Dossier for 2,2'-methylenebis(6-(2H-benzotriazol- 2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol), https://www.echa.europa.eu/web/guest/registration-dossier/-/registered-dossier/5321. 21. European Chemicals Agency, Registration Dossier for 2,2'-methylenebis(6-(2H-benzotriazol- 2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol), https://www.echa.europa.eu/web/guest/registration-dossier/-/registered-dossier/13964. 22. European Chemicals Agency, Registration Dossier for 2-(2H-1,2,3-benzotriazol-2-yl)-6-(2- phenylpropan-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol, https://www.echa.europa.eu/web/guest/registration-dossier/-/registered-dossier/15623. 23. Nakata, H.; Murata, S.; Filatreau, J.; Environmental Science and Technology, 43, 2009, 6920-6926. 24. Kim, J.-W.; Isobe, T.; Ramaswamy, B.; Chang, K.-H.; Amano, A.; Miller, T.; Siringan, F.; and Tanabe, S.; Chemosphere, 85, 2011, 751-758. 25. Nakata, H.; Shinohara, R-I.; Nakazawa, Y.; Isobe, T.; Sudaryanto, A.; Subramanian, A.; Tanabe, S.; Zakaria, M.; Zheng, G.; Lam, P.; Kim, E.; Min, B.-Y.; We, S.-U.; Viet, P.; Tana, T.; Prudente, M.; Donnell, F.; Lauenstein, G.; and Kannan, K.; Marine Pollution Bulletin, 64, 2012, 2211-2218. 26. Peng, X.; Jin, J.; Wang, C.; Ou, W.; Tang, C.; Journal of Chromatography A, 1384, 2015, 97-106. 27. Wick, A.; Jacobs, B.; Kunkel, U.; Heininger, P.; Ternes, T.; Environmental Pollution, 212, 2016, 401-412. 28. Heine, L.; Franjevic, S.; Issues in Environmental Science and Technology, 36; Chemical Alternative Assessments; Hester, R., Harrison, R., Eds.; The Royal Society of Chemistry; 2013; pp 129-156. 29. Clean Production Action, GreenScreen® for Safer Chemicals, https://www.greenscreenchemicals.org. 30. Washington State Department of Ecology, Assessing Chemical Hazards with the Quick Chemical Assessment Tool (QCAT), https://ecology.wa.gov/Regulations-Permits/Guidance- technical-assistance/Preventing-hazardous-waste-pollution/Safer-alternatives/Quick-tool-for- assessing-chemicals. 31. Clean Production Action, GreenScreen List Translator™, https://www.greenscreenchemicals.org/learn/greenscreen-list-translator. 32. Healthy Building Network, Pharos Project, https://www.pharosproject.net. 33. Office of Pollution Protection and Toxics, US Environmental Protection Agency, TSCA Work Plan Methods Document, February 2012, https://www.epa.gov/assessing-and-managing- chemicals-under-tsca/tsca-work-plan-methods-document.
  11. 11. © 2018 James H. Botkin dba BotkinChemie Page 11 of 19 Table 1. Chemical Identity of Benzotriazole UV Absorbers. Generic Name Chemical Name CAS No. Chemical Structure UV-P 2-(2H-Benzotriazol-2-yl)-p-cresol 2440-22-4 UV-234 2-(2H-Benzotriazol-2-yl)-4,6-bis(1- methyl-1-phenylethyl)phenol 70321-86-7 UV-320 2-Benzotriazol-2-yl-4,6-di-tert- butylphenol 3846-71-7 UV-326 2-tert-Butyl-4-methyl-6-(5- chlorobenzotriazol-2-yl)phenol 3896-11-5 UV-327 2,4-Di-tert-butyl-6-(5- chlorobenzotriazol-2-yl)phenol 3864-99-1 UV-328 2-(2H-Benzotriazol-2-yl)-4,6-di-tert- pentylphenol 25973-55-1 UV-329 2-(2H-Benzotriazol-2-yl)-4-(1,1,3,3- tetramethylbutyl)phenol 3147-75-9 UV-350 2-(2H-Benzotriazol-2-yl)-4-(tert- butyl)-6-(sec-butyl)phenol 36437-37-3 UV-360 2,2'-Methylenebis(6-(2H- benzotriazol-2-yl)-4-(1,1,3,3- tetramethylbutyl)phenol) 103597-45-1 UV-928 2-(2H-1,2,3-benzotriazol-2-yl)-6-(2- phenylpropan-2-yl)-4-(2,4,4- trimethylpentan-2-yl)phenol 73936-91-1
  12. 12. © 2018 James H. Botkin dba BotkinChemie Page 12 of 19 Table 2. Hazard Scoring Summary for UV-328 and Alternatives. Acute Toxicity Carc. Muta. Repr. Tox Dev. Tox Neurotox. Chronic Toxicity Resp. Sens. Aquatic Acute Aquatic Chronic Hazard Score UV-P 1 1 1 1 1 - 2 - 1 3 3 UV-234 1 - 1 - 1 - 2 - 1 1 2 UV-326 1 1 1 1 1 - 1 - 1 1 1 UV-328 1 - 1 2 1 - 3 - 1 - 3 UV-329 1 - 1 1 1 - 2 - 1 1 2 UV-360 1 - 1 1 1 - 1 - 1 1 1 UV-928 1 - 1 - 1 - 1 - 1 1 1 Notes: Endpoint scores and Hazard Scores given in italics are deemed to be of low confidence.
  13. 13. © 2018 James H. Botkin dba BotkinChemie Page 13 of 19 Table 3. Acute Toxicity Data for UV-328 and Alternatives. Generic Name Oral LD50 Reliability Score Inhalation LC50 Reliability Score Dermal LD50 Reliability Score Hazard Score UV-P Rat, 10,000 mg/kg Mouse, >5,000 mg/kg Rat, >5,000 mg/kg Mouse, 6,500 mg/kg Rat, >15,380 mg/kg Mouse, >5,500 mg/kg 2 4 4 4 3 4 Rat (4 h), >0.59 mg/L Rat (1.2 h), >163 mg/L Rat (4 h), >1.42 mg/L 2 4 4 Rat, >2,000 mg/kg Unk., >3,038 mg/kg Rat, >1,000 mg/kg 4 3 2 1 UV-234 Rat, >7,750 mg/kg 2 No data - Rat, >2,000 mg/kg 1 1 UV-326 Rat, >2,000 mg/kg Rat, >7,750 mg/kg Mouse, >5,000 mg/kg Rat, >5,000 mg/kg Rat, >2,110 mg/kg 1 2 4 4 2 Rat (4 h), >0.27 mg/L 3 Rat, >2,000 mg/kg 2 1 UV-328 Rat, >7,750 mg/kg Rat, >2,000 mg/kg Rat, >7,100 mg/kg Mouse, >5,000 mg/kg Rat, >5,000 mg/kg 2 2 2 2 2 Rat (4 h), >0.4 mg/L Rat (1 h) > 0.129 mg/L 2 2 Rabbit, >1,100 mg/kg 2 1 UV-329 Rat, >10,000 mg/kg 2 No data - Rabbit, >5,000 mg/kg 2 1 UV-360 Rat, >2,000 mg/kg Rat, >5,000 mg/kg - 2 No data - Rat, >2,000 mg/kg - 1 UV-928 Rat, >2,000 mg/kg Rat, >2,000 mg/kg Rat, >5,000 mg/kg 1 1 1 No data - Rat, >2,000 mg/kg Rat, >2,000 mg/kg Rabbit, >2,000 mg/kg 1 1 1 1 Notes: The benzotriazole UV absorbers generally present low acute toxicity by the oral and dermal routes, but only limited data are available for the inhalation route. Data with a reliability score of 3 were deemed to be not reliable and were not used to determine the score. Applying the TSCA Work Plan Chemical Scoring criteria yields a score of 1 (low) for all seven substances.
  14. 14. © 2018 James H. Botkin dba BotkinChemie Page 14 of 19 Table 4. Carcinogenicity and Mutagenicity/Genotoxicity Data for UV-328 and Alternatives. Generic Name Carcinogenicity Reliability Score Hazard Score Mutagenicity/Genotoxicity Reliability Score Hazard Score UV-P Rat, OECD 452, negative Mouse, OECD 451, negative 1 1 1 OECD 476, negative OECD 471, negative in vitro gene mutation in bacteria, negative in vitro gene mutation in bacteria, negative in vitro gene mutation in bacteria, negative 1 1 3 3 3 1 UV-234 No data - - OECD 471, negative OECD 482, negative OECD 474, negative EPA OTS 798.5915, negative 2 2 2 2 1 UV-326 Mouse, OECD 451, negative Rat, OECD 453, negative 2 2 1 OECD 473, negative OECD 471, negative OECD 471, negative OECD 478, negative OECD 474, negative OECD 475, negative 1 1 2 2 2 2 1 UV-328 No data - - OECD 471, negative OECD 473, negative OECD 476, negative 2 1 1 1 UV-329 No data - - OECD 471, negative OECD 473, negative OECD 476, negative in vitro DNA damage / repair study, negative 2 1 1 4 1 UV-360 No data - - OECD 471, negative OECD 473, negative OECD 476, negative - - - 1 UV-928 No data - - OECD 471, negative OECD 473, negative OECD 476, negative OECD 471, negative 1 1 1 1 1 Notes: UV-P and UV-326 are deemed to be negative for carcinogenicity based on the results of 2-year studies in rats and mice. Applying the TSCA Work Plan Chemical Scoring criteria yields a score of 1 (low) for UV-P and UV-326. For the other substances no score could be assigned due to lack of data. No positive results for mutagenicity/genotoxicity were obtained for UV-328 or the alternatives. Applying the TSCA Work Plan Chemical Scoring criteria yields a score of 1 (low) for all seven substances.
  15. 15. © 2018 James H. Botkin dba BotkinChemie Page 15 of 19 Table 5. Reproductive and Developmental Toxicity Data for UV-328 and Alternatives. Generic Name Reproductive Toxicity Reliability Score Hazard Score Developmental Toxicity Reliability Score Hazard Score UV-P OECD 422 (rat), NOAEL 300 mg/kg/d 1 1 OECD 414 (rat), NOAEL 1,000 mg/kg/d OECD 414 (mouse), NOEL 1,000 mg/kg/d 2 1 1 UV-234 Not deemed to be toxic to reproduction based on a lack of reproductive effects observed in 28 and 90-day repeated dose studies (rats), and in an OECD 414 study. However, this may not be sufficient to assign a score under the TSCA Work Plan Chemical Scoring criteria, and no hazard score was assigned. - - OECD 414 (rat), NOEL 3,000 mg/kg/d 2 1 UV-326 OECD 422 (rat), NOAEL 1,000 mg/kg/d 1 1 OECD 414 (rat), NOAEL 3,000 mg/kg/d OECD 414 (mouse), NOAEL 3,000 mg/kg/d 2 1 UV-328 OECD 422 (rat), NOEL 250 mg/kg/d (read across from structural analog) 2 2 OECD 414 (rat), NOAEL 1,000 mg/kg/d 2 1 UV-329 OECD 422 (rat), NOAEL 300 mg/kg/d (read across from structural analog) 2 1 OECD 414 (rat), NOAEL 1,000 mg/kg/d (read across from structural analog) 2 1 UV-360 OECD 415 (rat), NOEL 300 mg/kg/d Fertility study (rat), NOEL 1,000 mg/kg/d One generation study (rat), NOEL 1000 mg/kg/d - - - 1 OECD 414 (rat), NOAEL 1,000 mg/kg/d - 1 UV-928 No data - - OECD 414 (rat), NOAEL 3,000 mg/kg/d (read across from structural analog) 2 1 Notes: No reproductive toxicity data were available for UV-234 and UV-928, and therefore no score was assigned. The scores for the other substances were obtained by applying the TSCA Work Plan Chemical Scoring criteria to the NOAEL or NOEL values from the studies. UV-328 was assigned a score of 2 (medium), and the remaining substances (UV-P, UV-326, UV-329, UV-360) were assigned scores of 1 (low). The scores for UV-328 and UV-329 were deemed to be of low confidence since they are based on structural analog data.
  16. 16. © 2018 James H. Botkin dba BotkinChemie Page 16 of 19 Table 6. Chronic Toxicity Data for UV-328 and Alternatives. Chronic Toxicity Reliability Score Hazard Score UV-P OECD 422, rat, 42-53 d, NOAEL = 30 mg/kg/d OECD 409, dog, 90 d, NOEL = 33 mg/kg/d OECD 452, rat, 104 wk, NOEL = 1,000 ppm OECD 408, rat, 90 d, NOEL = 2,000 ppm OECD 409, dog, 90 d, NOEL = 1000 ppm No guideline, rat, 6 d/wk for 4 wk, NOEL = 2,500 ppm 1 3 1 2 1 3 2 UV-234 OECD 408, rat, 90 d, NOAEL = 22.3 mg/kg/d OECD 407, rat, 28 d, NOAEL = 933.8 mg/kg/d 2 2 2 UV-326 OECD 408, rat, 90 d, NOAEL = 637-740 mg/kg/d OECD 422, rat, 42-53 d, NOAEL = 1000 mg/kg/d OECD 453, rat, 104 wk, NOEL = 113.2-147.7 mg/kg/d OECD 409, dog, 90 d, NOAEL = 153-168 mg/kg/d OECD 407, rat, 28 d, NOAEL = 1,005.7 mg/kg/d OECD 451, mouse, 104 wk, NOAEL = 59-62 mg/kg/d No guideline, rat, 28 d, NOAEL = 500 ppm 2 1 2 2 2 2 3 1 UV-328 OECD 408, rat, 90 d, no NOAEL, LOAEL = 10 mg/kg/d OECD 409, Dog, 90 d, NOAEL = 30 mg/kg/d 2 2 3 UV-329 OECD 422, rat, 42-53 d, NOAEL = 30 mg/kg/d (structural analog) OECD 452, rat, 104 wk, NOAEL = 142-169 mg/kg/d (structural analog) No guideline, rat, 28 d, NOAEL = 5,658 mg/kg/d 2 2 3 2 UV-360 OECD 408, rat, 90 d, NOAEL = 1,000 mg/kg/d OECD 411, rat, 90 d, NOEL = 1,000 mg/kg/d OECD 407, rat, 28 d, NOEL = 1,000 mg/kg/d - - - 1 UV-928 OECD 408, rat, 90 d, NOEL = 1,000 mg/kg/d OECD 408, rat, 90 d, NOAEL = 1,000 mg/kg/d OECD 407, rat, 28 d, NOEL = 1,000 mg/kg/d 1 2 2 1 Notes: The chronic toxicity scores were obtained by applying the TSCA Work Plan Chemical Scoring criteria to the NOAEL or NOEL values from the studies. Data with a reliability score of 3 were deemed to be not reliable and were not used to determine the score. UV-328 was assigned a score of 3 (high), UV-P and UV-234 were assigned scores of 2 (medium), and the remaining substances (UV-326, UV-329, UV-360, UV-928) were assigned scores of 1 (low). The score for UV-329 was deemed to be of low confidence since it was based on structural analog data.
  17. 17. © 2018 James H. Botkin dba BotkinChemie Page 17 of 19 Table 7. Acute and Chronic Aquatic Toxicity Data for UV-328 and Alternatives. Generic Name Acute Aquatic Toxicity Reliability Score Hazard Score Chronic Aquatic Toxicity Reliability Score Hazard Score UV-P Fish (96 h), LC50 > 0.17 mg/L Fish (96 h), LC50 > 100 mg/L Fish (48 h), LC50 > 200 mg/L Daphnia (24 h), EC50 > 1,000 mg/L Algae (72 h), ErC50 > 0.0822 mg/L 1 2 2 2 1 1 Daphnia (21 d), NOEC = 0.013 mg/L 1 3 UV-234 Fish (96 h), LC50 > 67 mg/L Daphnia (48 h), EC50 > 100 mg/L Daphnia (24 h), LC50 > 10 mg/L Daphnia (24 h), EC50 > 91 mg/L Algae (72 h), EC50 > 100 mg/L 2 1 4 3 2 1 Daphnia (21 d), NOEC ≥ 10 mg/L 1 1 UV-326 Fish (96 h), LC50 > 100 mg/L Daphnia (48 h), EC50 > 100 mg/L Daphnia (48 h), LC50 > 10 mg/L Daphnia (24 h), EC50 > 100 mg/L Algae (24 h), EC50 > 100 mg/L 2 1 4 3 2 1 Daphnia (21 d), NOEC ≥ 10 mg/L 1 1 UV-328 Fish (96 h), LC50 > 100 mg/L Fish (96 h), LC50 > 0.078 mg/L Daphnia (48 h), LC50 > 10 mg/L Daphnia (24 h), EC50 > 100 mg/L Daphnia (48 h), EC50 > 0.083 mg/L Algae (72 h), ErC50 > 0.016 mg/L Algae (72 h), EC50 > 10 mg/L 2 2 4 4 2 2 2 1 No data - - UV-329 Fish (96 h), EC50 >100 mg/L Daphnia (48 h), EC50 > 100 mg/L Daphnia (48 h), LC50 > 10 mg/L Daphnia (24 h), EC50 = 15 mg/L Algae (72 h), EC50 > 100 mg/L 2 1 4 3 2 1 Daphnia (21 d), NOEC ≥ 10 mg/L 1 1 UV-360 Fish (96 h), LC50 > 28.9 mg/L Fish (96 h), LC50 > 10 mg/L Fish (96 h), LC50 > 12.7 mg/L Daphnia (48 h), LC50 > 65.9 mg/L - - - - 1 Fish (8 wk), NOEC > 1 mg/L Daphnia (21 d), NOEC > 0.025 mg/L - - 1
  18. 18. © 2018 James H. Botkin dba BotkinChemie Page 18 of 19 Daphnia (48 h), EC50 > 50.2 mg/L Daphnia (24 h), LC50 > 100 mg/L Daphnia (48 h), EC50 > 100 mg/L Algae (72 h), EC50 > 2 mg/L Algae (72 h), EC50 > 2 mg/L 2 - - - 2 UV-928 Fish (96 h), LC50 > 0.33 mg/L Fish (96 h), LC50 > 0.21 mg/L Daphnia (48 h), EC50 > 0.9 mg/L Algae (72 h), ErC50 > 0.66 mg/L Algae (72 h), ErC50 > 0.41 mg/L 1 1 1 1 1 1 Daphnia (21 d), NOEC ≥ 2 mg/L 1 1 Notes: Applying the TSCA Work Plan Chemical Scoring criteria yields an acute aquatic toxicity score of 1 (low) for all seven substances. Data with a reliability score of 3 were deemed to be not reliable and were not used to determine the score. No chronic aquatic toxicity data were available for UV-328 and therefore no score was assigned. The chronic toxicity scores for the other substances were obtained by applying the TSCA Work Plan Chemical Scoring criteria to the NOEC values from the studies. UV-P was assigned a chronic aquatic toxicity hazard score of 3 (high), and the remaining five substances (UV-234, UV-326, UV-329, UV-360, UV-928) were assigned chronic aquatic toxicity hazard scores of 1 (low).
  19. 19. © 2018 James H. Botkin dba BotkinChemie Page 19 of 19 Table 8. Bioaccumulation Scores, Persistence Scores, Total Scores, and Annex XIII Classifications for UV-328 and Alternatives. BCF Reliability B Score P Score PB Score Hazard Score Total Score Annex XIII Classification UV-P 44-494 2 1 3 2 3 5 not PBT, not vPvB UV-234 415-1,286 5.4-10.4 1 3 2 3 3 2 5 not PBT, not vPvB UV-326 54-895 2 1 3 2 1 3 not PBT, not vPvB UV-328 1,120-5,580 570-1,800 2 2 3 3 3 3 6 PBT, vPvB UV-329 361-461 1 1 3 2 2 4 not PBT, not vPvB UV-360 0.1-1.5 - 1 3 2 1 3 not PBT, not vPvB UV-928 415-1,286 361-461 6-27 1 1 2 2 3 3 1 4 not PBT, not vPvB Notes: The Bioaccumulation (B) scores were obtained by applying the TSCA Work Plan Chemical Scoring criteria to the maximum BCF values from the REACH dossiers. UV-328 received a B Score of 3 (high), UV-234 and UV-928 received B Scores of 2 (medium), and the remaining four substances (UV-P, UV-326, UV-329, UV-360) received B Scores of 1 (low). The B Score for UV-928 was deemed to be of low confidence as it was based on structural analog data and is given in italics. All of the benzotriazoles were assumed to be highly persistent and assigned Persistence (P) Scores of 3 (high). The B and P Scores were normalized according to the TSCA Work Plan Chemical Scoring method to PB Scores. UV-234, UV-328, and UV-928 received PB Scores of 3 (high), and the remaining four substances (UV-P, UV-326, UV-329, UV-360) received PB Scores of 2 (medium). The PB Score for UV-928 was deemed to be of low confidence since the underlying B Score was based on structural analog data, and is given in italics. The PB and Hazard Scores (from Table 2) were added together to give a Total Score. UV-328 received a Total Score of 6 (very high), UV-P and UV-234 received Total Scores of 5 (high), UV-329 and UV-928 received Total Scores of 4 (medium), and UV-326 and UV-360 received Total Scores of 3 (medium-low). The Total Scores for UV-329 and UV-928 were deemed to be of low confidence since the underlying B and/or Hazard Scores were based on structural analog data, and are given in italics. The benzotriazoles were also rated according to the REACH Annex XIII criteria for PBT and vPvB chemicals. Based on the available data, only UV-328 met the criteria for PBT or vPvB.

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