Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: - | CAS number: -
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
- Endpoint:
- activated sludge respiration inhibition testing
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- The UVCB - Reaction products of boric acid and calcium dihydroxide and lithium hydroxide (EC # 701-453-3) has structural similarities to two already established categories: lithium salts of the oxyacids of boron (B); and calcium salts of the oxyacids of boron (B). Dilithium tetraborate (EC# 234-514-3) (source substance #1) and calcium metaborate (EC# 237-224-5) (source substance #2) will be used to predict the properties for the target substance.
In the environment, all lithium/calcium borate substances in the categories rapidly dissociate and release the same common compound, boric acid as a result of relevant transformation pathways (e.g. hydrolytic, oxidative, digestive or metabolic) at environmentally relevant conditions (i.e., pH and concentration). This boric acid component of the salt is expected to drive the ecotoxicological and environmental fate properties.
Literature evidence is documented in the attached category approach document and states that several lithium and calcium borates are precursors of boric acid.
Boric acid, [B(OH)3], is a very weak, monobasic acid that acts as a Lewis acid by accepting a hydroxyl ion to form the borate anion, [B(OH)4]-. Therefore at higher concentrations and pH levels greater than 9.2, the borate anion [B(OH)4]- becomes predominant.
B(OH)3 + 2H2O¿[B(OH)4]- + H3O+
Therefore, at the near neutral pH of most environmental and ecotoxicological systems and at low concentrations (<0.025 mol B/L), the neutral mononuclear species (B(OH)3) will dominate and only a small proportion of boron will exist as the borate monoanion, B(OH)4- (WHO, 1998).
Based on existing information sourced from the scientific and regulatory literature it is concluded that all the lithium/calcium borate substances in these categories are expected to react similarly in the environment, forming boric acid if exposed to water or moist soils in the environment. As a result, read-across to dilithium tetraborate is proposed for this endpoint for the REACH registration of Reaction products of boric acid and calcium dihydroxide and lithium hydroxide. - Reason / purpose for cross-reference:
- read-across source
- Key result
- Duration:
- 3 h
- Dose descriptor:
- other: ELR50
- Effect conc.:
- > 1 000 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Key result
- Duration:
- 3 h
- Dose descriptor:
- other: ELR10
- Effect conc.:
- 440 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Duration:
- 3 h
- Dose descriptor:
- other: ELR20
- Effect conc.:
- 813 mg/L
- Nominal / measured:
- nominal
- Conc. based on:
- test mat.
- Basis for effect:
- inhibition of total respiration
- Conclusions:
- Reaction products of boric acid and calcium dihydroxide and lithium hydroxide is not expected to be toxic to waste water bacteria (activated sludge) at or below a loading rate of 320 mg/L (NOELR).
- Executive summary:
In a OECD 209 test, dilithium tetraborate was not toxic to waste water bacteria (activated sludge) at or below a loading rate of 320 mg/L (NOELR).
As all lithium/calcium borate substances in these categories rapidly dissociate and release the same common compound, boric acid in environmental systems, then any variations in structure between the substances are not expected to lead to any changes in the toxicity of the substances to activated sludge. It is therefore expected that Reaction products of boric acid and calcium dihydroxide and lithium hydroxide is not toxic to waste water bacteria (activated sludge) as well.
Reference
Description of key information
In a OECD 209 test, dilithium tetraborate was not toxic to waste water bacteria (activated sludge) at or below a loading rate of 320 mg/L (NOELR).
As all lithium/calcium borate substances in these categories rapidly dissociate and release the same common compound, boric acid in environmental systems, then any variations in structure between the substances are not expected to lead to any changes in the toxicity of the substances to activated sludge. It is therefore expected that Reaction products of boric acid and calcium dihydroxide and lithium hydroxide is not toxic to waste water bacteria (activated sludge) as well.
Key value for chemical safety assessment
- EC50 for microorganisms:
- 1 000 mg/L
- EC10 or NOEC for microorganisms:
- 440 mg/L
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
