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EC number: 217-982-3 | CAS number: 2031-62-1
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Key value for chemical safety assessment
Effects on fertility
Description of key information
Screening study for reproductive/developmental toxicity (RA-A CAS 78 -62 -6, OECD 422, oral, rat): NOAEL systemic toxicity and fertility = 300 mg/kg bw/day
Link to relevant study records
- Endpoint:
- screening for reproductive / developmental toxicity
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.
- Reason / purpose for cross-reference:
- read-across source
- Description (incidence and severity):
- There were no ophthalmoscopic findings in any of the animals of this study.
- Dose descriptor:
- NOAEL
- Remarks:
- systemic
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- mortality
- body weight and weight gain
- food consumption and compound intake
- organ weights and organ / body weight ratios
- histopathology: non-neoplastic
- Dose descriptor:
- NOAEL
- Remarks:
- reproductive toxicity
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- reproductive function (sperm measures)
- reproductive performance
- Critical effects observed:
- yes
- Lowest effective dose / conc.:
- 1 000 mg/kg bw/day (actual dose received)
- System:
- male reproductive system
- Organ:
- testes
- Treatment related:
- yes
- Dose response relationship:
- no
- Relevant for humans:
- not specified
- Dose descriptor:
- NOAEL
- Generation:
- F1
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- viability
- clinical signs
- body weight and weight gain
- Critical effects observed:
- no
- Reproductive effects observed:
- yes
- Lowest effective dose / conc.:
- 1 000 mg/kg bw/day (actual dose received)
- Treatment related:
- yes
- Relation to other toxic effects:
- reproductive effects as a secondary non-specific consequence of other toxic effects
- Dose response relationship:
- no
- Relevant for humans:
- not specified
- Conclusions:
- A combined repeated dose toxicity study with a reproductive/developmental toxicity screening test was performed with the source substance diethoxy(dimethyl)silane according to OECD TG 422 and GLP at dose levels of 100, 300 and 1000 mg/kg bw/day. The NOAEL for general systemic toxicity and reproductive toxicity can be established at 300 mg/kg bw/day. General systemic toxicity was based on increased mortality, adversely reduced body weight, food consumption, and histopathology effects to the kidney and testes at the highest dose level. Developmental toxicity was based on an increase of still births, a prolonged gestation period, reduced delivery index, higher postimplantation loss, decreased litter weight, and a reduced viability index at the highest dose. As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in reproduction toxicity potential.
Reference
Effect on fertility: via oral route
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- NOAEL
- 300 mg/kg bw/day
- Study duration:
- subacute
- Species:
- rat
- Quality of whole database:
- Hazard assessment is conducted by means of read-across based on a read-across from a structural analogue. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substance and overall assessment of quality, duration and dose.
Effect on fertility: via inhalation route
- Endpoint conclusion:
- no study available
Effect on fertility: via dermal route
- Endpoint conclusion:
- no study available
Additional information
No data on the reproductive toxicity of diethoxy(methyl)silane (CAS 2031-62-1) are available. Therefore, the risk assessment was performed based on the available data from the source substance diethoxy(dimethyl)silane (CAS 78-62-6). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the Read across assessment framework (RAAF, ECHA 2017) read across from the analogue substance has been applied to support the human health hazard assessment of diethoxy(methyl)silane (CAS 2031-62-1). Details on read across justifications can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.
A key study (combined repeated dose toxicity study with reproductive/developmental toxicity screening test (oral)) with diethoxy(dimethyl)silane (CAS 78-62-6) is available and was performed according to OECD TG 422 and in compliance with GLP (Eurofins, 2018). The test substance was administered daily in graduate doses (100, 300, and 1000 mg/kg bw/day) to 3 groups of test animals per gavage, one dose level per group for a treatment period of up to 54 days, i.e. during 14 days of pre-mating and maximum 14 days of mating in both males and females, during gestation period and up to post-natal day 3 in females. Males were dosed after the mating period until the minimum total dosing period of 28-29 days was completed. Animals of an additional control group were handled identically as the dose groups but received corn oil, the vehicle used in this study.
In order to allow a detection of possible delayed occurrence or persistence of or recovery from toxic effects, additional animals in recovery groups were observed for a period of 14 days following the last administration. Animals in the recovery groups were not mated and dosed for 28 days (males) or until the first scheduled euthanasia of dams (females).
As described in the repeated dose toxicity chapter systemic toxicity was observed in the highest dose group based on mortality, reduced body weight and food consumption and histopathological findings in the kidney and testes. With regard to reproductive toxicity effect, there was a moderate tubular degeneration which correlated with reduced weight in testes of high-dose males. The elongated and round spermatids of stages V-VII were mainly affected. More mature spermatids and spermia appeared to be almost unaffected. In some tubules, there were reabsorbed apoptotic bodies or Sertoli cell vacuolation. In the epididymides, only a minimal severity of cellular detritus (shedded epithelia and/or pyknotic sperm cells) was recorded in most 1000-mg/kg bw/day males. Therefore, it is deemed that the sperm became damaged late during the study period, and hence, fertility was not affected during the mating period. While these findings were still present after the recovery period, a partial recovery cannot be judged since the recovery time was much too short (i.e., sperm cycle in rats takes between 56-58 days) for recovery.
Treatment-related effects also were observed in offspring at 1000 mg/kg bw/day. Still births were seen in 6/8 dams at 1000 mg/kg bw/day with an increased mean number of 5.00 still births when compared to 0.11 in controls. In relation to the increase in still births, gestation period was noted to be prolonged. The delivery index was shown to be markedly reduced (56%) when compared to 100% in the control group. Accordingly, percentage of post-implantation loss was markedly higher (51.31%) when compared to the control group (6.57%).
No adverse effects of diethoxy(dimethyl)silane were found at the lower dose levels tested. Thus, the NOAEL for reproductive toxicity could be established at 300 mg/kg body weight/day.
Taking into consideration the above results generated from the structurally analogue substance the target substance is expected to show similar toxicity after repeated exposure.
Effects on developmental toxicity
Description of key information
Screening study for reproductive/developmental toxicity (RA-A CAS 78 -62 -6, OECD 422, oral, rat): NOAEL systemic toxicity and developmental toxicity = 300 mg/kg bw/day
Effect on developmental toxicity: via oral route
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- NOAEL
- 300 mg/kg bw/day
- Study duration:
- subacute
- Species:
- rat
- Quality of whole database:
- Hazard assessment is conducted by means of read-across based on a read-across from a structural analogue. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substance and overall assessment of quality, duration and dose.
Effect on developmental toxicity: via inhalation route
- Endpoint conclusion:
- no study available
Effect on developmental toxicity: via dermal route
- Endpoint conclusion:
- no study available
Additional information
For assessment of the developmental toxicity properties of diethoxy(methyl)silane (CAS 2031 -62 -1) read-across was applied using the structural analogue substance, diethoxy(diemthyl)silane (CAS 78 -62 -6). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the Read across assessment framework scenario 2 (RAAF, ECHA 2017) read across from an analogue substance has been applied to support the human health hazard assessment of diethoxy(methyl)silane (CAS 2031 -62 -1). Details on read across justifications can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.
A key study (combined repeated dose toxicity study with reproductive/developmental toxicity screening test (oral)) with diethoxy(dimethyl)silane (CAS 78-62-6) is available and was performed according to OECD TG 422 and in compliance with GLP (Eurofins, 2018). The test substance was administered daily in graduate doses (100, 300, and 1000 mg/kg bw/day) to 3 groups of test animals per gavage, one dose level per group for a treatment period of up to 54 days, i.e. during 14 days of pre-mating and maximum 14 days of mating in both males and females, during gestation period and up to post-natal day 3 in females. Males were dosed after the mating period until the minimum total dosing period of 28-29 days was completed. Animals of an additional control group were handled identically as the dose groups but received corn oil, the vehicle used in this study.
Test item-related mortality occurred at the highest dose level of 1000 mg/kg bw/day. Beforehand, both affected adult females were seen with general signs of reduced health condition and were found dead or were euthanised for animal welfare shortly after delivery of still born pups. Mortality was related to renal tubular necrosis. One further female dosed with 1000 mg/kg bw/day was also observed with reduced health condition after delivery of still births.
Treatment-related effects were observed in offspring at 1000 mg/kg bw/day. Still births were seen in 6/8 dams at 1000 mg/kg bw/day with an increased mean number of 5.00 still births when compared to 0.11 in controls. Total litter weight at 1000 mg/kg bw/day was also affected based on the lower number of live pups.Test item-related, adverse effects were also noted for pup survival. At 1000 mg/kg bw/day a reduced viability index of 75.56% was seen when compared to 100.00% in the control group.
No adverse effects of diethoxy(dimethyl)silane were found at the lower dose levels tested. Thus, the NOAEL for reproductive toxicity could be established at 300 mg/kg body weight/day.
Taking into consideration the above results generated from the structurally analogue substance the target substance is expected to show similar toxicity after repeated exposure.
Justification for classification or non-classification
Based on the information from an adequate read-across substance, it is concluded that the available information on reproductive toxicity does not meet the criteria for classification according to Regulation (EC) No. 1272/2008, and is therefore conclusive but not sufficient for classification.
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.
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