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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 401-850-9 | CAS number: 255881-94-8 X4261
PBT assessment
Administrative data
PBT assessment: overall result
- PBT status:
- the substance is not PBT / vPvB
- Justification:
In order for a substance to be considered as PBT, it has to fulfil all the three criteria as listed in REACh for Persistence, Bioaccumulation and Toxicity. If it can be shown that the substance does not fulfil at least one of these criteria then it will not be considered as PBT.
HiTec 511 has a reported Log Kowof greater than 4.5 thereby fulfilling the REACh screening criteria for Bioaccumulation. Aquatic toxicity data for the substance indicates a No Observed Effect Concentration (NOEC) of <0.01 mg/L and hence fulfils the criteria for Toxicity.
Whilst biodegradation tests suggest limited biodegradation of the substance occurs in standard ready biodegradation tests, an enhanced biodegradation test has shown much improved levels of biodegradation. PBT assessment for HiTec 511 is therefore concentrated on showing that the substance should not be considered as Persistent, and hence is not considered PBT.
Biodegradation Study Data
The substance has a reported water solubility of 1.4 mg/L at 20oC and hence this limits the suitability of the methods outlined in the OECD 301 Ready Biodegradability test guidelines. The ECHA guidance document Chapter R.7b: Endpoint specific guidance (ECHA, 2008, p.191) states that:
“It should be noted that substances being considered as potentially PBT/vPvB are often poorly soluble in water and this may cause significant difficulties in the conduct of the test, and in particular low levels of biodegradation may be observed due to low substance availability.”
A MITI (I) Ready Biodegradation test showed no biodegradation within a 28-Day period (Mitsubishi Chemical Safety Institute Ltd., 1996). This result would suggest that the substance is Persistent; however in this study no methods were implemented to improve the dispersibility or bioavailability of the substance. The lack of biodegradation in this study could therefore be attributed to low substance availability as a result of the low aqueous solubility of the test substance.
Modern studies in which techniques that maximize the bioavailability of low solubility substances are employed are believed to provide results that are more representative of the biodegradation potential of such substance. Therefore in line with current recommendations (ECHA, 2008) an enhanced biodegradation study was conducted (Brixham Environmental Laboratory, 2011). In this study the test design was enhanced to improve the bioavailability of the substance following the recommendations of van Ginkelet al(van Ginkel, 2008). The effect of these enhancements was assessed by testing the substance alone and in the presence of silicone oil and a combination of silicone oil and surfactant. Other adaption’s to the standard test method were to increase the test volume thus increasing the likelihood of competent organisms being present, and extending the study duration up to 63 days to allow for a longer lag period.
The results of this enhanced biodegradation study confirmed that where no silicone oil or surfactant were present the substance showed no biodegradation. However, where bioavailability was increased by the use of a combination of silicone oil and surfactant, a maximum mean level of biodegradation of 46% was observed during the test, with a single replicate attaining 57% biodegradation. It was therefore concluded that increasing the bioavailability of the substance had a significant effect on the biodegradability.
Discussion
Laboratory assessments of biodegradability are stringent in their nature and hence it is recognized that a negative or low result“does not necessarily mean that the chemical will not be degraded under relevant environmental conditions and persist in the environment”(ECHA, 2008, p.170).
In the natural environment the presence of humics and other suspended solids in natural waters provide an ideal surface onto which low solubility, high Kowtype substances can adsorb. The effect of such processes on increasing their dispersibility and hence their bioavailability leading to increased biodegradation levels has been reported (Handleyet al, 2002). The concentrations of substances in the environment are also significantly lower than those employed in laboratory biodegradation tests and it has been shown that biodegradation rates at environmentally relevant concentrations are generally higher than those obtained in laboratory studies (Kleĉkaet al, 2001).
Taking into account the factors above combined with the significant increase in biodegradation observed in the enhanced biodegradation test, it is considered that in the natural environment, where conditions for biodegradation are more favourable, the substance would not be Persistent.
It is therefore concluded that on the grounds of a lack of Persistence in the environment, the substance should not be considered as PBT.
References
BRIXHAM ENVIRONMENTAL LABORATORY (2011)Report No BR0410/B X-4261: Enhanced biodegradation test (modified OECD 301 D)
EUROPEAN CHEMICALS AGENCY (ECHA) (2008)Guidance on information requirements and chemical safety assessment Chapter R.7b: Endpoint specific guidance.
HANDLEY, J. W., MEAD, C., RAUSINA, G. A., WAID, L. J., GEE, J. C. and HERRON, S. J. (2002) The Use of Inert Carriers in Regulatory Biodegradation Tests of Low Density Poorly Water-soluble Substances.Chemosphere,Volume 48, Issue 5, Pages 529-34
MITSUBISHI CHEMICAL SAFETY INSTITUTE LTD (1996)M.S.I. Report No. 6B061G Ready Biodegradability Test of X4261
van Ginkel, C.G., Gancet, C., Hirschen, M., Galobardes, M., Lemaire, Ph.andRosenblom, J.(2008) Improving ready biodegradability testing of fatty amine derivatives,Chemosphere, Volume 73, Issue 4, Pages 506-510
Kleĉka, G. M., Gonsior, S. J., West, R. J., Goodwin, P. A.andMarkham, D. A.(2001) Biodegradation of bisphenol a in aquatic environments: River die-away.Environmental Toxicology and Chemistry, Volume 20, Pages 2725–2735
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.
