Ethane, 1,1,2-trichloro-1,2-difluoro-

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

The testing laboratory was the competent Authority. Although some details on exposure are not reported in the report and therefore the results cannot be interpreted.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

Deviations:

yes

Remarks:

4-month treatment, only males rats treated, no data on exposure frequency, all animals of treated and control goups sacrificed after one month-recovery period.

Principles of method if other than guideline:

3 groups of 20 male rats were treated for 4 months with the test material at 3 different concentrations. A concurrent negative control group of 20 males was trated with air only. No information on the exposure frequency is reported.
Observations were made on monthly basis starting from the day 10 of exposure.
All the animals were sacrificed after one month-recovery period and subjected to necropsy.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,1,2-trichloro-1,2-difluoroethane

EC Number:

940-543-9

Cas Number:

354-15-4

Molecular formula:

C2HCl3F2

IUPAC Name:

1,1,2-trichloro-1,2-difluoroethane

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): R 122

Test animals

Species:

rat

Strain:

other: non-pedigree

Sex:

male

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

4 months

Frequency of treatment:

no data

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/m³ air

Doses / concentrations 2

Dose / conc.:

10 mg/m³ air

Doses / concentrations 3

Dose / conc.:

100 mg/m³ air

Doses / concentrations 4

Dose / conc.:

1 000 mg/m³ air

No. of animals per sex per dose:

20

Control animals:

yes, concurrent vehicle

Results and discussion

Effect levels

Key result

Dose descriptor:

NOAEC

Effect level:

100 mg/m³ air

Based on:

act. ingr.

Sex:

male

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

haematology

Target system / organ toxicity

Critical effects observed:

yes

Lowest effective dose / conc.:

1 000 mg/m³ air

Any other information on results incl. tables

Assessment of the general body condition

The study showed that in the first 7-10 days of the experiment the animals that were exposed to HCFC 122a at a concentration of 1000 mg/m³developed apathy and lethargy. However, the observed changes disappeared by the end of the first month of the experiment.

Exposure to HCFC 122a at concentrations of 10 and 100 mg/m³did not cause changes in appearance and behaviour of the experimental animals.

 

The study of the dynamics of body weight in rats showed that HCFC 122a in the highest concentration caused significant reduction in body weight gain starting from the third month of the experiment. However, during the recovery period, the difference in body weight in this group of animals levelled up.

Exposure to HCFC 122a at concentrations of 10 and 100 mg/m³caused no significant changes in weight of the experimental animals as compared to the control group.

 

Effects on the morphological composition of the blood.

Investigation of the peripheral blood revealed that HCFC 122a at a concentration of 1000 mg/m³caused a statistically significant decrease in the erythrocyte count starting from the third month of the experiment and an increase in the leukocyte count in peripheral blood.

During the recovery period, the leukocyte count returned to the level of the control group, but the erythrocyte count remained significantly reduced. No change in hemoglobin count was observed during the entire observation period.

Exposure to the refrigerant at a concentration of 100 mg/m³only increased the leukocyte count in blood at the end of the experiment.

At a concentration of 10 mg/m³, HCFC 122a did not cause morphological changes in blood throughout the entire chronic experiment.

 

Leukocyte count in peripheral blood

Substance concentration	Testing time
	1st month	2nd month	3rd month	4th month	Recovery period
10 mg/m^3	12.9±3.5	14.6±3.5	12.2±3.1	18.8±3.1	13.7±2.7
100 mg/m^3	15.0±2.2	13.1±3.5	14.8±3.5	27.5±2.2	15.1±3.0
1000 mg/m^3	28.6±3.9	16.6±2.1	28.7±5.3	21.6±1.3	19.6±2.6
Control	13.7±2.2	12.9±3.5	19.1±2.1	14.6±2.2	13.8±1.9

  

Erythrocyte count in blood

10 mg/m^3	4.95±0.7	4.0±0.2	4.8±0.2	5.85±0.3	5.2±0.4
100 mg/m^3	3.9±0.3	4.5±0.3	4.7±0.2	5.05±0.08	4.9±0.25
1000 mg/m^3	3.56±0.23	4.55±0.24	2.9±0.28	4.4±0.15	4.0±0.3
Control	4.62±0.23	4.3±0.4	5.0±0.3	5.4±0.1	5.1±0.2

 

Hemoglobin content in blood

10 mg/m^3	15.0±0.8	17.0±0.4	15.4±0.5	16.1±0.5	14.7±0.7
100 mg/m^3	15.2±0.4	15.6±1.0	13.7±0.6	14.2±1.5	13.8±0.6
1000 mg/m^3	13.8±0.5	16.6±0.5	13.6±1.01	13.6±0.1	14.3±0.4
Control	12.65±0.8	14.0±0.4	14.6±0.5	14.0±0.7	14.8±0.6

 

Effects on the nervous system.

The functional state of the nervous system of experimental animals in the chronic experiment was assessed using the following indicators: summation-threshold value, orientation-exploratory activity, and the “split” value.

Study of the functional state of the nervous system using the summation-threshold value showed that the most pronounced changes in this indicator were observed in animals exposed to HCFC 122a at a concentration of 1000 mg/m³, which were noted already starting from the second month of the experiment. It should be noted that the detected change did not get to normal during the recovery period.

At a concentration of 100 mg/m³, the refrigerant caused changes in summation-threshold value only in the first month of experience, but later on there was no difference from the control group.

HCFC 122a at a concentration of 10 mg/m³caused only a tendency to changes in the summation-threshold value at the end of the experiment.

Along with the changes in the summation-threshold value, a significant reduction in exploratory activity in laboratory animals was also observed.

The most significant changes in this indicator took place upon exposure to HCFC 122a at a concentration of 1000 mg/m³. Identified changes were persistent and no reversibility of the effects was observed by the end of the recovery period.

At a concentration of 100 mg/m³, HCFC 122a caused changes in the exploratory reaction of rats at the end of the 4th month of the experiment. No changes in this indicator were observed upon exposure to the substance at a concentration of 10 mg/m³.

The study of the “split” value characterizing the state of the neuromuscular system revealed only a trend towards its increase in the group of animals exposed to the substance at a concentration of 1000 mg/m³.

 

Thus, studies to assess the functional state of the nervous system in case of chronic poisoning with HCFC 122a revealed that the studied compound has a pronounced effect on the nervous system, reducing the activity of nerve cells and lowering the lability of nervous processes.

 

 

Dynamics of changes in summation-threshold value (STV)

Substance concentration	Testing time
	1st month	2nd month	3rd month	4th month	Recovery period
10 mg/m^3	6.1±0.6	6.2±0.2	6.3±0.2	8.8±0.3	7.6±0.4
100 mg/m^3	6.3±0.3	8.9±0.3	6.7±0.3	9.3±0.4	8.3±0.6
1000 mg/m^3	6.4±0.2	8.7±0.5	9.1±0.2	13.1±0.86	11.0±0.7
Control	6.5±0.43	6.5±0.43	6.7±0.2	7.9±0.32	6.8±0.45

 

Effects on the functional state of the liver.

Liver function was assessed using tests that were sensitive while determining the threshold acute effect. Study on the activity of sorbitol dehydrogenase (SDH), lactate dehydrogenase-5 (5-LDH) specific to the liver tissue and transaminases were conducted.

These studies showed that HCFC 122a at a concentration of 1000 mg/m³can cause increased activity of SDH from the first month of the experiment, and the activity of this enzyme in blood serum remained high till the end of the experiment.

No changes in this indicator were observed upon exposure to the substance at a concentrations of 10 and 100 mg/m³.

The study of 5-LDH isoenzyme allowed to establish its significant increase in blood serum throughout the experiment in the group of animals exposed to the substance at a concentration of 1000 mg/m³and a tendency to increased activity of the enzyme at the end of experiment.

Exposure to HCFC 122a at the lower tested concentration did not change this indicator.

Determination of transaminases activity in the blood serum upon exposure to the refrigerant allowed to observe significant increase in activity of this enzyme at the end of the first month of the experiment at a concentration of 1000 mg/m³.

The results of the study of SH groups content in the peripheral blood of experimental animals showed that at the lowest tested concentrations (10 and 100 mg/m³) HCFC 122a caused no significant alterations of this indicator. Exposure to a concentration of 1000 mg/m³caused significant decrease in SH groups in the blood at the end of the 4th month of the experiment; however, one month after cessation of administartion, the content of SH groups in the blood of animals of this group did not differ from controls.

 

Activity of sorbitol hydrogenase in the blood serum

Substance concentration	Testing time
	1st month	2nd month	3rd month	4th month	Recovery period
10 mg/m^3	4.9±0.7	5.3±0.6	9.3±1.2	7.04±1.3	7.4±0.9
100 mg/m^3	5.6±0.7	6.5±0.8	8.7±1.9	5.5±2.5	6.1±0.8
1000 mg/m^3	12.1±0.9	44.0±6.4	12.5±1.4	13.6±1.4	14.3±2.0
Control	4.6±0.8	4.1±0.9	5.2±2.5	9.18±2.8	6.3±1.2

 

SH group content in blood (general)

Substance concentration	Testing time
	1st month	2nd month	3rd month	4th month	Recovery period
10 mg/m^3	2,580±70	2,195±53	2,698±34	2,150±55	1,860±200
100 mg/m^3	2,518±160	2,266±31	2,654±110	2,155±39	2,230±253
1000 mg/m^3	2,760±21	2,196±55	2,585±78	1,535±80	1,950±210
Control	2,251±29	2,071±139	2,326±69	2,250±156	2,438±206

 

SH group content in blood (non-protein)

10 mg/m^3	5,703±1,234	2,611±50	2,221±109	3,126±1,063	2,514±87
100 mg/m^3	2,393±479	2,500±35	1,980±44	1,985±34	1,990±65
1000 mg/m^3	2,040±89	2,683±25	1,591±191	1,381±131	1,890±46
Control	2,558±90	4,627±858	3,150±1,410	2,023±46	2,139±110

 

 

The study of the histamine content in the blood of experimental animals allowed to establish a significant decrease of this index when exposed to HCFC 122a at a concentration of 1000 mg/m³. At a concentration of 100 mg/m³, the substance caused just a tendency to reduction of the histamine content in the blood, and at a concentration of 10 mg/m³, this indicator did not significantly different from the control group.

Histamine content in blood

10 mg/m^3	6.48±0.45	3.9±0.4	3.8±0.6	3.3±0.3	6.9±0.8
100 mg/m^3	5.2±0.66	4.9±0.5	3.9±0.3	3.9±0.9	6.6±0.8
1000 mg/m^3	6.4±0.32	4.6±0.7	3.7±0.7	3.8±0.9	5.4±0.8
Control	7.01±0.8	5.8±0.8	4.3±1.1	4.9±0.9	6.2±0.7

 

Applicant's summary and conclusion

Conclusions:

Basing on the results a NOAEC of 100 mg/m3 can be extrapolated. However, although the testing institute is the competent Authority and results are described, essential information on exposure are not provided and therefore the results cannot be interpreted.

Executive summary:

The reported subchronic toxicological study was conducted by the Ministry of Health of the Russian Federation in order to establish the threshold of chronic action and validate the maximum allowable concentration of HCFC 122a in the air of the working area.

The study was performed on 3 groups of 20 male rats each, at the concentration of 10, 100, and 1000 mg/m3. A control group was included in the experiment.

The study plan was defined taking into account the existing data on the biological action of HCFC 122a and structurally related compounds and the physical and chemical properties of the substance.

Throughout the 4 -month administration, behaviour of animals, their appearance and weight were observed. Since similar compounds are known to have effects on the nervous system, test of neuro-muscular activity, motor activity, orientation response and “emotionality” were included. 

Analysis on the activity of sorbitol dehydrogenase, lactate dehydrogenase-5 specific to the liver tissue and transaminases were conducted in order assess potential functional changes in the liver.

Furthermore, since published data showed that similar compounds can affect the morphological composition of the blood,analysis of peripheral blood components morphology and of the immunological reactivity was performed. Observations of the functional state of the experimental animals were carried out on a monthly basis.The first examination was carried out on Day 10. In addition, in order to determine the stability of the identified changes, the state of the animals was assessed one month after the termination of administration. At the end of the experiment, the animals were sacrificed, followed by determination of weight factors of the internal organs and post-mortem examinations.

Statistical data processing was carried out using conventional methods with the calculation of mean values, their errors and Student’s t-test.

 

The results showed that the concentration of HCFC 122a of 1000 mg/m³can be described acting in the chronic experiment based on indicator reflecting the state of the nervous system, peripheral blood, and liver. Tests to assess the functional state of the nervous system in case of chronic exposure to HCFC 122a revealed that the studied compound has a pronounced effect on the nervous system at 1000 mg/m³, reducing the activity of nerve cells and lowering the liability of nervous processes.

Basing on the above described results a NOAEC of 100 mg/m3 can be extrapolated.