3,4-dichlorobenzonitrile

Endpoint summary

Description of key information

Acute Oral Toxicity:In an acute oral toxicity study equivalent to OECD 423 the LD50 of 3,4 -Dichlorobenzonitrile was established to be within the range of 200 -2000 mg/kg body weight. Because of this 3,4 -Dichlorobenzonitrile is classified as harmful and requires the hazard statement H302 - "Harmful if swallowed” according to Regulation(EC) No1272/2008.

Acute Dermal Toxicity:

In order to classify the substance 3,4 -Dichlorobenzonitrile (without any unneccessary animal testing) for this enpoint the testing results with 2-Chlorobenzonitrile and 2,6-Dichlorbenzonitrile are read acrossed to 3,4-Dichlorobenzonitrile. 2 -Chlorobenzonitrile was tested in a study equivalent to OECD Guideline 402 to be harmful in contact with skin and was classified as acute tox. 4 H312. This agrees with the official classification in acute dermal toxicity of 2,6 -Dichlorobenzonitrile. Therefore 3,4 -Dichlorobenzonitrile was classified as cute tox. 4 H312 ("Harmful in contact with 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:

1997-02-11 - 1997-02-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Qualifier:

equivalent or similar to guideline

Guideline:

other: Directive 96/54/EC, Part B.1 tris "Acute Toxicity-Oral, Acute Toxic Class Method"

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Sulzfeld, Germany.
- Age at study initiation: approx. 6 weeks
- Weight at study initiation: within +/- 20 % of the sex mean
- Fasting period before study: food was withheld overnight prior to dosing until approximately 3-4 hours after administration of the test substance.
- Housing: group housing of 3 animals per sex per cage in labelled polycarbonate cages containing purified sawdust as bedding material (Woody SPF, supplied by B.M.I, Helmond, The Netherlands)
- Diet (e.g. ad libitum): free access to standard pelleted laboratory animal diet (from Carfil Quality BVBA, Oud-Turnhout, Belgium)
- Water (e.g. ad libitum): free access to tap-water
- Acclimation period: at least 5 days before start of treatment under laboratory conditions.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 50
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): lighting was 12 hours artificial flourescent light and 12 hours dark per day

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

- Method: Oral gavage, using a stainless steel stomach tube.
- Frequency: Once, on day 1.
- Animals: 3 animals of the same sex per dose group.

Doses:

200 mg/kg (females), 200 mg/kg (males) and 2000 mg/kg (females)

No. of animals per sex per dose:

three

Control animals:

no

Details on study design:

OBSERVATIONS:
- Mortality/Viability: Twice daily. The time of death was recorded as precisely as possible
- Body weights: Days 1 (pre-administration), 8 and 15 and at death (if found death after day 1).
- Clinical signs: At periodic intervals on the day of dosing (day 1) and once daily thereafter, until day 15. The time of onset, degree and duration were recorded.

- Necropsy of survivors performed: yes

Statistics:

not performed

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 200 - < 2 000 mg/kg bw

Based on:

test mat.

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

> 200 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All femals dosed at 2000 mg/kg b.w. were found dead within 24 hours of dosing.

Clinical signs:

other: 200 mg/kg: Hunched posture, uncoordinated movements. 2000 mg/kg: Lethargy, hunched posture, uncoordinated movements, piloerection. The surviving animals had recovered from symptoms between days 2 and 3. The surviving animals had recovered from the sympto

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

The test substance was ranked within LD50 values ranges of 0 - 25, 25 - 200 or 200 - 2000 mg/kg b.w. or as exceeding 2000 mg/kg b.w.

No statistical analysis was performed (The method used is not intended to allow the calculation of a percise LD50 value).

The results were evaluated according to the EEC criteria for classification and labelling requirements for dangerous substances and preparations (Guidelines in Commission Directive 93/21/EEC, 27th april 1993).

Table 1: Body weights of test groups.

Group / Sex	Animal	Day 1 [g]	Day 2 [g]	Day 8 [g]	Day 15 [g]
Group 1 / females	1	126		179	202
	2	131		171	195
	3	122		161	170
	Mean	126		170	189
	St. Dev.	5		9	17
	N	3		3	3
Group 2 / males	4	185		249	283
	5	194		277	309
	6	186		239	277
	Mean	188		255	290
	St. Dev.	5		20	17
	N	3		3	3
Group 3 / females	7	138	137	-	-
	8	148	147	-	-
	9	143	137	-	-
	Mean	143		-	-
	St. Dev.	5		-	-
	N	3		0	0

Table 2: Observed clinical signs of test group 1 (females, 200 mg/kg)

Test day			1	1	1	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Time after treatment. hours			0	2	4
Animal number	Signs	max. grade
1	gait/motility: uncoordinated movements	(3)	-	1	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
2	gait/motility: uncoordinated movements	(3)	-	1	1	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
3	Posture: Hunched posture   gait/motility: uncoordinated movements	(1)     (3)	-     -	-     2	-     2	1     1	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -	-     -

Table 3: Observed clinical signs of test group 2 (males, 200 mg/kg)

Test day			1	1	1	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Time after treatment. hours			0	2	4
Animal number	Signs	max. grade
4	gait/motility: uncoordinated movements	(3)	-	1	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
5	gait/motility: uncoordinated movements	(3)	-	1	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
6	gait/motility: uncoordinated movements	(3)	-	1	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-

Table 4: Observed clinical signs of test group 3 (females, 2000 mg/kg).

Test day			1	1	1	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
Time after treatment. hours			0	2	4
Animal number	Signs	max. grade
7	Behavior: Lethargy   Posture: Hunched posture   gait/motility: uncoordinated movements	(3)     (1)     (3)	-     -     -	-     -     2	1     1     2	+     +     +
8	Posture: Hunched posture   gait/motility: uncoordinated movements	(1)     (3)	-     -	-     2	1     2	+     +
9	Posture: Hunched posture   gait/motility: uncoordinated movements   Skin /FUR / Plumage: Piloerection	(1)     (3)     (1)	-     -     -	-     2     1	1     2     1	+     +     +

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The oral LD50 value of 3,4-Dichlorobenzonitrile in Wistar rats was established to be within the range of 200-2000 mg/kg body weight.
According to the EEC criteria for classification and labelling, 3,4-Dichlorobenzonitrile must be classified as harmful if swallowed.
Based on the test result and observation, it can be expected that the classificatoin is also suitable for H302 where 300mg/kg is the threshold.

Executive summary:

The study was carried out based on the guidelines described by oral gavage to three femal Wister rats at 200 mg/kg body weight. In a stepwise procedure additional groups of animals were dosed at 200 (males) and 2000 (females) mg/kg body weight. All animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed on the day of death or after terminal sacrifice 8 (day 15).

All three animals dosed at 2000 mg/kg b.w. were found dead within 24 hours of dosing. The surviving animals recovered from all clinical signs observed between days 2 and 3. The body weight gain shown by the surviving animals over the study period was considered to be normal. No abnormalities were found at macroscopic post mortem examination of the animals.

The oral LD50 value of 3,4 -Dihchlorobenzonitrile in Wistar rats was established to be within the range of 200 -2000 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

300 mg/kg bw

Quality of whole database:

sufficient

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

There is no data available acute dermal toxicity testing with 3,4-Dichlorobenzonitrile. In order to classify the substance according to GHS relevant endpoint data available for 2,6-Dichlorobenzonitrile was read-acrossed to 3,4-Dichlorobenzonitrile based on structural similarities. 2,6-Dichlorobenzonitrile is as well as 3,4-Dichlorobenzonitrile, is a disubstituted Benzonitrile. Both substances only differ in the position of the chloro substituents. Furthermore both substances are solid, practically insoluble in water and have a water octanol partition coefficient of 2.2 and 2.8. This might perhaps also lead to a similiar dermal resorption of the substnces and therefore a similar toxicological behavior. In order to gain more information about 3,4-Dichlorobenzonitrile and to classify the substance (without any unneccessary animal testing) according to GHS the result of the acute dermal test with 2,6-Dichlorbenzonitrile was read acrossed.
For justsification of Read Across see section 13.2

Qualifier:

equivalent or similar to guideline

Guideline:

other: no guideline rreported

Principles of method if other than guideline:

The data was collected from a database only in order to classify the substance.

GLP compliance:

not specified

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

1 350 mg/kg bw

Based on:

test mat.

Interpretation of results:

Category 4 based on GHS criteria

Executive summary:

There is no data available on dermal toxicity testing with 3,4 -Dichlorobenzonitrile. In order to classify the substance (without any unnecessary animal testing) according to GHS relevant endpoint data for 2,6 -Dichlorobenzonitrile was read-acrossed to 3,4 -Dichlorobenzonitrile based on structural and physico chemical similarities (see rationale for reliability).

2,6 -Dichlorobenzonitrile is officially classified as acute Tox. 4 H312 ("Harmful in contact with skin"). Furthermore a entry in the Chemical Toxicity Database "RTECS number-DI3500000" refers a LD50 value of 1350 mg/kg, which also requires a classification as acute Tox. 4 H312.

Therefore and because of the same classification 2 -Chlorobenzonitrile in dermal toxicity, 3,4 -Dichlorobenzontrile was also classified as acute Tox. 4 H312.

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1976

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

There is no data available on dermal toxicity testing with 3,4-Dichlorobenzonitrile. In order to classify the substance according to GHS relevant endpoint data available for 2-Chlorobenzonitrile was read-acrossed to 3,4-Dichlorobenzonitrile based on structural and physico chemical similarities. 2-Chlorobenzonitrile, as well as 3,4 -Dichlorobenzonitrile is a Chloro substituted Benzonitrile. Although 2-Chlorobenzonitrile is only monosubstitueted both substances are solid, practically insoluble in water and have similar water octanol partition coefficients (2.2 and 2.8). This might perhaps also lead to a similiar dermal resorption and toxicological behavior.
See also "Justification for Read Across" in Section 13.2

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

initial weight: 2.23 - 3.06 kg

Type of coverage:

occlusive

Vehicle:

propylene glycol

Details on dermal exposure:

- The test material was dissoved in propylene glycol
- 9 ml of test dissolved test material contain the applied dose
- Half of the animals received the material on the intact skin, the other half on the abraded skin
- Occlusive conditions: treated area was covered with a thin layer of cellulose sheet and wrapped in polyethylene foil
- After exposure for 24 h the test material was removed with water and the animals were wrapped dry

Duration of exposure:

24 hours

Doses:

0, 0.19, 0.34, or 0.6 g/kg body weight

No. of animals per sex per dose:

2 (Half of the animals received the material on the intact skin, the other half on the abraded skin).

Control animals:

yes, concurrent vehicle

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: no data
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology (liver, kidney, spleen, stomach, treated and untreated skin), other: blood composition

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 340 - <= 600 mg/kg bw

Based on:

test mat.

Mortality:

4 (all) animals in the highest dose groupe (600 mg/kg, during teh first days of the observation period); 0 in the 340 mg/kg group, 1 in the 190 mg/kg group (sufferd from diarrhoea and died during teh second week)

Clinical signs:

other: During or at the end of the 24-hour exposure period no abnormalities of the treated skin could be observed in any of the test groups. However, all test rabbits were more or less apathetic. In addition the animals of the highest dose group had widened pupi

Gross pathology:

Gross and microscopical examination revealed haemorrhagic erosions in the stomach and massive centrolobular liver necrosis in animals of the 0.6 g/kg dose group. Damage of the liver and stomach was obserevd after treatment with 0.6 g/kg body weight. There were no distinct differences in reactions either between rabbits treated on the intact or abraded skin or between male and female rabbits.

Other findings:

- Haemoglobin content of the blood and red blood cell counts of rabbits of the 0.34 g/kg dose group were slightly higher than those of control rabbits. Those differences are not considered to be of toxicological significance since values are within the normal range.
- At autopsy, groes examination of the rabbits of the highest dose group, which died during the experiment, revealed haemorrhagic erosions in the stomach of three rabbits. The animal of the lowest dose group that died and the rabbits that survived the experiment did not show macroscopic changes attributable to treatment.
- microscopical examination revealed treatment-related changes in the liver and stomach. Two rabbits of the highest dose group showed massive centrilobular liver necrosis, while small foci of centrilobular liver necrosis were observed in one rabbit of each test group. It is not clear whether these liver injuries are the result of a direct toxic action of the test compound or of an indirect effect resulting from anoxia.
- Three rabbits of the highest doce group showed haemorrhagic erosions in the fundic part of the stomach, which was considered to be due to preterminal conditional decline.
- Other abnormalities in liver, kidneys, heart and the treated skin occurred to about the sarme degree and frequency in test and control animals or occurred in a single rabbit and are, therefore, not considered te be of toxicological significance.

Table – individual body weight

number	sex	Dose (mg/kg)	Condition of skin	Body weight day 0 (kg)	Body weight end of week 1 (kg)	Body weight end of week 2 (kg)
3638	M	0	abraded	3.06	3.09	3.36
3639	M	0	intact	2.60	2.55	2.78
3627	F	0	abraded	2.93	2.88	3.13
3625	F	0	intact	2.93	2.30	2.45
3641	M	190	abraded	3.05	3.07	3.32
3644	M	190	intact	2.45	2.43	2.82
3662	F	190	abraded	2.55	1.77	dead
3663	F	190	intact	2.70	2.68	3.00
3645	M	340	abraded	2.65	2.83	2.82
3646	M	340	Intact	3.05	3.00	3.36
3660	F	340	abraded	2.62	2.85	3.15
3661	F	340	intact	2.32	2.50	3.02
3635	M	600	abraded	3.05	dead	dead
3637	M	600	intact	2.61	dead	dead
3621	F	600	abraded	2.88	dead	dead
3622	F	600	intact	2.36	dead	dead

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The dermal LD50 of 2-Chlorobenzonitrile is between 340 and 600 mg/kg bw in rabbits under conditions of this study.
It should be noted that resorption of the test substance has probably been enhanced due to the application in propylene glycol. Therefore, 2-Chlorobenzonitrile is not classified as H311 ("Toxic in contact with skin") but H312 ("Harmful in contact with skin").

Executive summary:

The acute dermal toxicity of 2-Chlorobenzonitrile was examined in an experiment with 8 adult New Zealand White Rabbits/sex/dose. The animals were treated with 2-Chlorobenzonitrile dissolved in propylene glycol at dose levels of 0, 0.19, 0.34 or 0.6 g/kg body weight for 24h. Half the number of animals received the material on the intact skin, the other half on abraded skin.

The dermal application caused apathy of the rabbits in all test groups and widened pupils, tremors and paresis or paralysis in the highest dose group. All animals of the highest dose group died during the first days. The animals of the other groups recovered completely, except one rabbit of the 0.19 g/kg dose group that suffered from diarrhoea and died during the second week of the observatiuon period.

The dermal LD50 of 2 -Chlorobenzonitrile was concluded to be between 340 and 600 mg/kg bw.

It should be noted that resorption of the test substance has probably been enhanced due to the application in propylene glycol. Therefore, 2-Chlorobenzonitrile is not classified as H311 ("Toxic in contact with skin") but H312 ("Harmful in contact with skin").

As there is no data available on dermal toxicity testing with 3,4 -Dichlorobenzonitrile relevant endpoint data available for 2 -Chlorobenzonitile was read-acrossed to 3,4 -Dichlorobenzonitrile in order to classify the substance (without any unecessary animal testing) according to GHS. The Read-Across approach was based on structural and physico chemical similarities (see rational for reliability).

2 -Chlorobenzonitrile was tested in a study equivalent to OECD Guideline 402 (Acute Dermal Toxicity) to be harmful in contact with skin and was classfied as acute tox. 4 H312. This agrees with the official classification in acute dermal toxicity of 2,6 -Dichlorobenzonitrile. Therefore 3,4 -Dichlorobenzonitrile was classified as acute Tox. 4 H312 ("Harmful in contact with skin".)

Reference 3

Endpoint:

acute toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

here is no data available acute dermal toxicity testing with 3,4-Dichlorobenzonitrile. In order to classify the substance according to GHS relevant endpoint data available for 2,6-Dichlorobenzonitrile was read-acrossed to 3,4-Dichlorobenzonitrile based on structural similarities. 2,6-Dichlorobenzonitrile is as well as 3,4-Dichlorobenzonitrile, is a disubstituted Benzonitrile. Both substances only differ in the position of the chloro substituents. Furthermore both substances are solid, practically insoluble in water and have a water octanol partition coefficient of 2.2 and 2.8. This might perhaps also lead to a similiar dermal resorption of the substnces and therefore a similar toxicological behavior. In order to gain more information about 3,4-Dichlorobenzonitrile and to classify the substance (without any unneccessary animal testing) according to GHS the result of the acute dermal test with 2,6-Dichlorbenzonitrile was read acrossed.
See also Justification for Read Across in Section 13.2

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

other: no guidline reported

Principles of method if other than guideline:

The data was collected from a database only in order to classify the substance.

GLP compliance:

not specified

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

1 350 mg/kg bw

Based on:

test mat.

Interpretation of results:

Category 4 based on GHS criteria

Executive summary:

There is no data available on dermal toxicity testing with 3,4 -Dichlorobenzonitrile. In order to classify the substance (without any unnecessary animal testing) according to GHS relevant endpoint data for 2,6 -Dichlorobenzonitrile was read-acrossed to 3,4 -Dichlorobenzonitrile based on structural and physico chemical similarities (see rationale for reliability).

2,6 -Dichlorobenzonitrile is officially classified as acute Tox. 4 H312 ("Harmful in contact with skin"). Furthermore a entry in the Chemical Toxicity Database "RTECS number-DI3500000" refers a LD50 value of 1350 mg/kg, which also requires a classification as acute Tox. 4 H312.

Therefore and because of the same classification 2 -Chlorobenzonitrile in dermal toxicity, 3,4 -Dichlorobenzontrile was also classified as acute Tox. 4 H312.

Reference 4

Endpoint:

acute toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

1976

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

There is no data available on dermal toxicity testing with 3,4-Dichlorobenzonitrile. In order to classify the substance according to GHS relevant endpoint data available for 2-Chlorobenzonitrile was read-acrossed to 3,4-Dichlorobenzonitrile based on structural and physico chemical similarities. 2-Chlorobenzonitrile, as well as 3,4 -Dichlorobenzonitrile is a Chloro substituted Benzonitrile. Although 2-Chlorobenzonitrile is only monosubstitueted both substances are solid, practically insoluble in water and have similar water octanol partition coefficients (2.2 and 2.8). This might perhaps also lead to a similiar dermal resorption and toxicological behavior.
See also "Justification for Read Across" in Section 13.2

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

initial weight: 2.23 - 3.06 kg

Type of coverage:

occlusive

Vehicle:

propylene glycol

Details on dermal exposure:

- The test material was dissoved in propylene glycol
- 9 ml of test dissolved test material contain the applied dose
- Half of the animals received the material on the intact skin, the other half on the abraded skin
- Occlusive conditions: treated area was covered with a thin layer of cellulose sheet and wrapped in polyethylene foil
- After exposure for 24 h the test material was removed with water and the animals were wrapped dry

Duration of exposure:

24 hours

Doses:

0, 0.19, 0.34, or 0.6 g/kg body weight

No. of animals per sex per dose:

2 (Half of the animals received the material on the intact skin, the other half on the abraded skin).

Control animals:

yes, concurrent vehicle

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: no data
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology (liver, kidney, spleen, stomach, treated and untreated skin), other: blood composition

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 340 - <= 600 mg/kg bw

Based on:

test mat.

Mortality:

4 (all) animals in the highest dose groupe (600 mg/kg, during teh first days of the observation period); 0 in the 340 mg/kg group, 1 in the 190 mg/kg group (sufferd from diarrhoea and died during teh second week)

Clinical signs:

other: During or at the end of the 24-hour exposure period no abnormalities of the treated skin could be observed in any of the test groups. However, all test rabbits were more or less apathetic. In addition the animals of the highest dose group had widened pupi

Gross pathology:

Gross and microscopical examination revealed haemorrhagic erosions in the stomach and massive centrolobular liver necrosis in animals of the 0.6 g/kg dose group. Damage of the liver and stomach was obserevd after treatment with 0.6 g/kg body weight. There were no distinct differences in reactions either between rabbits treated on the intact or abraded skin or between male and female rabbits.

Other findings:

- Haemoglobin content of the blood and red blood cell counts of rabbits of the 0.34 g/kg dose group were slightly higher than those of control rabbits. Those differences are not considered to be of toxicological significance since values are within the normal range.
- At autopsy, groes examination of the rabbits of the highest dose group, which died during the experiment, revealed haemorrhagic erosions in the stomach of three rabbits. The animal of the lowest dose group that died and the rabbits that survived the experiment did not show macroscopic changes attributable to treatment.
- microscopical examination revealed treatment-related changes in the liver and stomach. Two rabbits of the highest dose group showed massive centrilobular liver necrosis, while small foci of centrilobular liver necrosis were observed in one rabbit of each test group. It is not clear whether these liver injuries are the result of a direct toxic action of the test compound or of an indirect effect resulting from anoxia.
- Three rabbits of the highest doce group showed haemorrhagic erosions in the fundic part of the stomach, which was considered to be due to preterminal conditional decline.
- Other abnormalities in liver, kidneys, heart and the treated skin occurred to about the sarme degree and frequency in test and control animals or occurred in a single rabbit and are, therefore, not considered te be of toxicological significance.

Table – individual body weight

number	sex	Dose (mg/kg)	Condition of skin	Body weight day 0 (kg)	Body weight end of week 1 (kg)	Body weight end of week 2 (kg)
3638	M	0	abraded	3.06	3.09	3.36
3639	M	0	intact	2.60	2.55	2.78
3627	F	0	abraded	2.93	2.88	3.13
3625	F	0	intact	2.93	2.30	2.45
3641	M	190	abraded	3.05	3.07	3.32
3644	M	190	intact	2.45	2.43	2.82
3662	F	190	abraded	2.55	1.77	dead
3663	F	190	intact	2.70	2.68	3.00
3645	M	340	abraded	2.65	2.83	2.82
3646	M	340	Intact	3.05	3.00	3.36
3660	F	340	abraded	2.62	2.85	3.15
3661	F	340	intact	2.32	2.50	3.02
3635	M	600	abraded	3.05	dead	dead
3637	M	600	intact	2.61	dead	dead
3621	F	600	abraded	2.88	dead	dead
3622	F	600	intact	2.36	dead	dead

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The dermal LD50 of 2-Chlorobenzonitrile is between 340 and 600 mg/kg bw in rabbits under conditions of this study.
It should be noted that resorption of the test substance has probably been enhanced due to the application in propylene glycol. Therefore, 2-Chlorobenzonitrile is not classified as H311 ("Toxic in contact with skin") but H312 ("Harmful in contact with skin").

Executive summary:

The acute dermal toxicity of 2-Chlorobenzonitrile was examined in an experiment with 8 adult New Zealand White Rabbits/sex/dose. The animals were treated with 2-Chlorobenzonitrile dissolved in propylene glycol at dose levels of 0, 0.19, 0.34 or 0.6 g/kg body weight for 24h. Half the number of animals received the material on the intact skin, the other half on abraded skin.

The dermal application caused apathy of the rabbits in all test groups and widened pupils, tremors and paresis or paralysis in the highest dose group. All animals of the highest dose group died during the first days. The animals of the other groups recovered completely, except one rabbit of the 0.19 g/kg dose group that suffered from diarrhoea and died during the second week of the observatiuon period.

The dermal LD50 of 2 -Chlorobenzonitrile was concluded to be between 340 and 600 mg/kg bw.

It should be noted that resorption of the test substance has probably been enhanced due to the application in propylene glycol. Therefore, 2-Chlorobenzonitrile is not classified as H311 ("Toxic in contact with skin") but H312 ("Harmful in contact with skin").

As there is no data available on dermal toxicity testing with 3,4 -Dichlorobenzonitrile relevant endpoint data available for 2 -Chlorobenzonitile was read-acrossed to 3,4 -Dichlorobenzonitrile in order to classify the substance (without any unecessary animal testing) according to GHS. The Read-Across approach was based on structural and physico chemical similarities (see rational for reliability).

2 -Chlorobenzonitrile was tested in a study equivalent to OECD Guideline 402 (Acute Dermal Toxicity) to be harmful in contact with skin and was classfied as acute tox. 4 H312. This agrees with the official classification in acute dermal toxicity of 2,6 -Dichlorobenzonitrile. Therefore 3,4 -Dichlorobenzonitrile was classified as acute Tox. 4 H312 ("Harmful in contact with skin".)

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

350 mg/kg bw

Justification for classification or non-classification

Acute Oral Toxicity: In an acute oral toxicity study equivalent to OECD 423 the LD50 of 3,4 -Dichlorobenzonitrile was established to be within the range of 200 -2000 mg/kg body weight. Because of this 3,4 -Dichlorobenzonitrile is classified as harmful and requires the hazard statement H302 - "Harmful if swallowed” according to Regulation(EC) No1272/2008.

Acute Dermal Toxicity:

There is no data available on dermal toxicity studies with 3,4-Dichlorobenzonitrile. In order to classify the substance according to GHS relevant endpoint data available for 2-Chlorobenzonitrile and 2,6-Dichlorobenzonitrile was read-acrossed to 3,4-Dichlorobenzonitrile based on structural and physico chemical similarities.

2,6-Dichlorobenzonitrile, as well as 3,4 -Dichlorobenzonitrile is a disubstituted Benzonitrile. Both substances only differ in the position of the chloro substituents. 2-Chlorobenzonitile is a next lower homologon of 2,6-Dichlorobenzonitrile. Furthermore all three substances are solid, practically insoluble in water and have a water octanol partition coefficient between 2.2 and 2.8. This might perhaps also lead to a similiar toxicological behavior. The Read-Across approach assumes that if a Monochlorobenzonitrile and a Dichlorobenzonitril show similiar toxicological behavior, it is likely that a second Dichlorobenzonitril also shows this similar behavior. Particularly if it has the same physico chemical properties like practically insoluble in water and logKow between 2.2 and 2.8, which might lead to a comparable dermal resorption of the substances.

In order to classify the substance 3,4 -Dichlorobenzonitrile (without any unneccessary animal testing) for this enpoint the testing results with 2-Chlorobenzonitrile and 2,6-Dichlorbenzonitrile are read acrossed to 3,4-Dichlorobenzonitrile. 2 -Chlorobenzonitrile was tested in a study equivalent to OECD Guideline 402 to be harmful in contact with skin and was classified as acute tox. 4 H312. This agrees with the official classification in acute dermal toxicity of 2,6 -Dichlorobenzonitrile. Therefore 3,4 -Dichlorobenzonitrile was classified as cute tox. 4 H312 ("Harmful in contact with skin").