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Description of key information

Acute toxicity: oral
A K1 acute oral toxicity test was performed in male and female Sprague-Dawley rats according to a guideline similar to OECD Guideline 401 and according to the Code of Federal Regulations 16:1500.3 (Shapiro R, 1991). The LD50 was estimated to be 2800 mg/kg bw. This study was selected as key study.
Acute toxicity: inhalation
An acute inhalation study does not need to be conducted as the substance is classified as corrosive to the skin. In addition the substance appears asa clump and is produced as a solution. Therefore formation of respirable suspended particulate matter is unlikely.
Acute toxicity: dermal
An acute dermal study does not need to be conducted as the substance is classified as corrosive to the skin.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 4 February 1991 until 18 February 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented study performed according to Code of Federal Regulations 16:1500.3 and equivalent to OECD Guideline 401.
Qualifier:
according to guideline
Guideline:
other: Code of Federal Regulations 16:1500.3
Deviations:
not specified
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
no
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Davidson's Mill Farm, S. Brunswick, NJ
- Age at study initiation: no data
- Weight at study initiation: males body weight range: 217 - 228 g; females body weight range: 206-221 g
- Fasting period before study: Rats were fasted on the day before dosing for approximately 18 hours by removing feed from their cages. During fasting, water was provided ad-libitum. After the 18 hour fast period, the rats were examined and weighed again.
- Housing: Individually in suspended stainless steel caging with mesh floors.
- Diet (e.g. ad libitum): Pelleted Purina Rat Chow ad-libitum
- Water (e.g. ad libitum): Tap water supplied by automatic water system
- Acclimation period: 6, 12 or 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.9 °C - 22.8°C
- Humidity (%): No data
- Air changes (per hr): No data
Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 50% w/w solution in distilled water
- Amount of vehicle (if gavage): 10 g

Doses:
The dose levels were 2500 and 3500 mg/kg
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The rats were observed at 1, 2 and 4 hours after dosing and at least once daily thereafter for signs of gross toxicity and mortality. Body weights were recorded initially and at termination (day 14) or after death.
- Necropsy of survivors performed: yes, all survivors to termination were euthanized by CO2 inhalation. Gross necropsies were performed on all decedents.
Statistics:
LD50 calculated by the Litchfield-Wilcoxon Method of Probit Analysis; J. Pharmacology and Experimental Therapeutics 96: 99-115 (1949)
Sex:
male/female
Dose descriptor:
LD50
Effect level:
2 800 mg/kg bw
Based on:
test mat.
95% CL:
2 360 - 3 320
Mortality:
Dosage 2500 mg/kg: 30% mortality occurred by day 2.
Dosage 3500 mg/kg: 90% mortality occurred by day 3.
Clinical signs:
Dosage 2500 mg/kg: Following test material administration all animals appeared lethargic. Most had a hunched posture and two had ano-genital staining. All surviving animals recovered from the above symptoms by day 6 and gained weight over the 14-day observation period.
Dosage 3500 mg/kg: Following test material administration, all animals appeared lethargic and most had hunched posture; several had ano-genital staining and diarrhea. Prior to death many were prostrated. The survivor (female) recovered from these toxic signs by day 4.
Body weight:
Dosage 2500 mg/kg: The three decedents, all females, lost bodyweight prior to death.
Dosage 3500 mg/kg: All decedents lost weight prior to death. The survivor (female) gained weight over the 14-day observation period.
Gross pathology:
Dosage 2500 mg/kg: Necropsy of the decedents revealed distention of the stomach with reddish-white discoloration of the pyloric region, discoloration of the intestines and dark-colored fluid in the bladder.
Dosage 3500 mg/kg: Necropsy of the decedents revealed distention of the stomach with discoloration of the pyloric region in most animals. Discoloration of the intestines and dark-colored fluid in the bladder was also noted in most animals.
Interpretation of results:
not classified
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute oral, single dose LD50 calculated by Probit Analysis was 2800 mg cerium trichloride per kilogram body weight with 95% confidence limits of 2360 and 3320 mg/kg. Based on the criteria of the CLP Regulation, the substance should not be classified for acute oral toxicity as the LD50 value is > 2000 mg/kg.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 800 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Acute toxicity: oral

Shapiro R (1991) investigated the acute oral toxicity via gavage of a single oral dose of cerium trichloride (50% aqueous solution) in 5 Sprague-Dawley rats per sex per dose. The dose levels tested were 2500 and 3500 mg/kg. The animals were observed for 14 days. At 2500 mg/kg 30% mortality occurred by day 2 and at 3500 mg/kg 90% mortality occurred by day 3. Following test material administration at 2500 mg/kg all animals appeared lethargic. Most had a hunched posture and two had ano-genital staining. All surviving animals recovered from the above symptoms by day 6 and gained weight over the 14-day observation period. At 3500 mg/kg all animals appeared lethargic and most had hunched posture; several had ano-genital staining and diarrhea. Prior to death many were prostrated. The survivor (female) recovered from these toxic signs by day 4. At 2500 mg/kg the three decedents, all females, lost bodyweight prior to death. At 3500 mg/kg all decedents lost weight prior to death. The survivor (female) gained weight over the 14-day observation period. At 2500 mg/kg necropsy of the decedents revealed distention of the stomach with reddish-white discoloration of the pyloric region, discoloration of the intestines and dark-colored fluid in the bladder. At 3500 mg/kg necropsy of the decedents revealed distention of the stomach with discoloration of the pyloric region in most animals. Discoloration of the intestines and dark-colored fluid in the bladder was also noted in most animals. The acute oral, single dose LD50 calculated by Probit Analysis was 2800 mg cerium trichloride per kilogram body weight. This study is designated as key study.

In addition, a K2 limit test reported a LD100 value of 5000 mg/kg bw (Shapiro, 1991). This study has been disregarded as the dose administered was inappropriate and the study did not permit to conclude about the toxicity of cerium chloride.

Acute toxicity: inhalation

An acute inhalation study does not need to be conducted as the substance is classified as corrosive to the skin (according to REACH Annex VIII section 8.5, column 2). In addition the substance appears as a clump and is produced as a solution. Therefore formation of respirable suspended particulate matter is unlikely.

Acute toxicity: dermal

An acute dermal study does not need to be conducted as the substance is classified as corrosive to the skin (according to REACH Annex VIII section 8.5, column 2).


Justification for selection of acute toxicity – oral endpoint
The LD50 is above 2000 mg/kg bw. Therefore, this is considered as showing no adverse effects.

Justification for classification or non-classification

Based on the results of the acute oral toxicity study and according to the criteria of the DSD and CLP Regulation, cerium trichloride should not be classified as an acute oral toxicant.

No data were available to decide on the classification for the inhalation and dermal route. As the substance is classified as corrosive to the skin, no acute test via a second route of exposure should be conducted.