Calcium cyanamide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1989-05-10 to 2014-05-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EU Method B.3 (Acute Toxicity (Dermal)) (Annex V of the 6th amendment of the EEC directive of 18th September, 1979, Part B, 4.1.3 Acute toxicity dermal)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Calcium cyanamide

EC Number:

205-861-8

EC Name:

Calcium cyanamide

Cas Number:

156-62-7

Molecular formula:

CN2.Ca

IUPAC Name:

calcium cyanoazanediide

impurity 1

Reference substance name:

Calcium oxide

EC Number:

215-138-9

EC Name:

Calcium oxide

Cas Number:

1305-78-8

Molecular formula:

CaO

IUPAC Name:

oxocalcium

impurity 2

Reference substance name:

Carbon

EC Number:

231-153-3

EC Name:

Carbon

Cas Number:

7440-44-0

Molecular formula:

C

IUPAC Name:

carbon

impurity 3

Reference substance name:

Hematite (Fe2O3)

EC Number:

215-275-4

EC Name:

Hematite (Fe2O3)

Cas Number:

1317-60-8

Molecular formula:

Fe2O3

IUPAC Name:

diiron oxide

impurity 4

Reference substance name:

Urea

EC Number:

200-315-5

EC Name:

Urea

Cas Number:

57-13-6

Molecular formula:

CH4N2O

IUPAC Name:

urea

impurity 5

Reference substance name:

Silicon dioxide

EC Number:

231-545-4

EC Name:

Silicon dioxide

Cas Number:

7631-86-9

Molecular formula:

O2Si

IUPAC Name:

dioxosilane

impurity 6

Reference substance name:

Trisilicon tetranitride

EC Number:

234-796-8

EC Name:

Trisilicon tetranitride

Cas Number:

12033-89-5

Molecular formula:

N4Si3

IUPAC Name:

trisilicon tetranitride

impurity 7

Reference substance name:

Calcium dihydroxide

EC Number:

215-137-3

EC Name:

Calcium dihydroxide

Cas Number:

1305-62-0

Molecular formula:

CaH2O2

IUPAC Name:

calcium dihydroxide

impurity 8

Reference substance name:

Aluminium oxide

EC Number:

215-691-6

EC Name:

Aluminium oxide

Cas Number:

1344-28-1

Molecular formula:

Al2O3

IUPAC Name:

aluminium oxide

impurity 9

Reference substance name:

Cyanoguanidine

EC Number:

207-312-8

EC Name:

Cyanoguanidine

Cas Number:

461-58-5

Molecular formula:

C2H4N4

IUPAC Name:

2-cyanoguanidine

impurity 10

Reference substance name:

Calcium acetylide

EC Number:

200-848-3

EC Name:

Calcium acetylide

Cas Number:

75-20-7

Molecular formula:

C2Ca

IUPAC Name:

calcium ethynediide

impurity 11

Reference substance name:

unknown

IUPAC Name:

unknown

Test material form:

solid: particulate/powder

Details on test material:

Kalkstickstoff (calcium cyanamide, technical grade)

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: A. Smith, Warlingham, Surrey, England
- Age at study initiation: approximately 9 - 12 weeks
- Weight at study initiation: weight range of 2.7 - 3.1 kg
- Fasting period before study: no
- Housing: individually in metal cages with perforated floors
- Diet: standard laboratory diet ad libitum
- Water: ad libitum
- Acclimation period: 14 days prior to start of the main study


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 21°C
- Humidity (%): 54%
- Air changes (per hr): 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours artificial light in each 24 hour period (i.e. 12 hours dark / 12 hours light)

Test system

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 2 g/kg bw

Duration of treatment / exposure:

24 h

Observation period:

15 days

Number of animals:

preliminary study: one male and one female
main study: 5 male and 5 female

Details on study design:

TEST SITE
- Area of exposure: dorso-lumbar region
- % coverage: 10% of total body surface
- Type of wrap if used: the treated area was covered with gauze, held in place with an impermeable dressing encircled firmly around the trunk


REMOVAL OF TEST SUBSTANCE
- Washing: washing with warm (30-40°C) water and blotting dry with absorbent paper
- Time after start of exposure: 24 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2 g/kg bw, both for preliminary and main study
- Concentration (if solution): test substance moistened with distilled water at 1 mL/kg
- Constant volume or concentration used: yes
- For solids, paste formed: yes, test substance moistened with distilled water at 1 mL/kg

VEHICLE
- Amount(s) applied (volume or weight with unit): test substance moistened with distilled water at 1 mL/kg
- Duration of observation period following administration: Animals of the preliminary and main studies were observed for 5 and 14 days, respectively, after dosing.
- Frequency of observations and weighing: Animals were observed soon after dosing, then at frequent intervals for the remainder of Day 1 and at subsequent days at least twice per day. Individual bodyweights of rabbits in the main study were recorded on Days 1, 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs were recorded at each observation (nature, severity, approximate time of onset and duration of toxic sign), body weight, macroscopic post mortem examination (opening the abdominal and thoracic cavities)

The treated areas of the skin were examined daily for signs of dermal irritation and assessed according to the following arbitrary scoring system:

Erythema and eschar formation:
0 no erythema
1 slight erythema
2 well-defined erythema
3 moderate erythema
4 severe erythema (beet redness) to slight eschar formation (injuries in depth)

Oedema formation:
0 no oedema
1 slight oedema
2 well-defined oedema (area well-definite by definite raising)
3 moderate oedema (raised approximately 1 mm)
4 severe oedema (raised more than 1 mm and extending beyond the area of exposure)

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Results 2

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Results 3

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 10 days

Remarks on result:

positive indication of irritation

Results 4

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Results 5

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 7

Irritation parameter:

erythema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

1.6

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 8

Irritation parameter:

edema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Results 9

Irritation parameter:

erythema score

Basis:

animal #5

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 11 days

Remarks on result:

positive indication of irritation

Results 10

Irritation parameter:

edema score

Basis:

animal #5

Time point:

24/48/72 h

Score:

1.6

Max. score:

4

Reversibility:

fully reversible within: 10 days

Remarks on result:

positive indication of irritation

Results 11

Irritation parameter:

erythema score

Basis:

animal #6

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Results 12

Irritation parameter:

edema score

Basis:

animal #6

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 11 days

Remarks on result:

positive indication of irritation

Results 13

Irritation parameter:

erythema score

Basis:

animal: #7

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 11 days

Remarks on result:

positive indication of irritation

Results 14

Irritation parameter:

edema score

Basis:

animal: #7

Time point:

24/48/72 h

Score:

2.3

Max. score:

4

Reversibility:

fully reversible within: 11 days

Remarks on result:

positive indication of irritation

Results 15

Irritation parameter:

erythema score

Basis:

animal: #8

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 16

Irritation parameter:

edema score

Basis:

animal: #8

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 17

Irritation parameter:

erythema score

Basis:

animal: #9

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Results 18

Irritation parameter:

edema score

Basis:

animal: #9

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Results 19

Irritation parameter:

erythema score

Basis:

animal: #10

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 10 days

Remarks on result:

positive indication of irritation

Results 20

Irritation parameter:

edema score

Basis:

animal: #10

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

Well-defined to severe erythema accompanied by well-defined to moderate erythema were observed in all treated animals after removal of the dressings. Irritation had resolved in two male and two female rabbits by Day 10 or 11 and in further two animals (one male and one female) by Day 14. Irritation was still present in the remaining two males and two females at the end of the study (Day 15).
Small areas of necrosis were present in one male and two females from Day 2 until the end of the study. Necrotic patches were observed in a further three males and two females from Day 3 and until Day 9 (with the exception of one male where the necrotic patch was still present at the end of the study).

Other effects:

Mortality
There were no deaths following a single dermal dose of calcium cyanamide, technical grade, at 2 g/kg bw.

Clinical signs
There were no clinical signs of systemic toxicity in response to treatment.

Body weight
A slightly lower bodyweight gain was recorded for one female on Day 15. All other animals achieved anticipated gains throughout the study.

Gross pathology
At terminal autopsy, red streaks were observed in the left ventricle of the heart of one male rabbit. Small cysts were also observed on the outer surface of the kidney of the same male. A large fluid-filled cyst (10 x 10 cm) was also present in the kidney. Small cysts were also observed on the surface of the kidneys of one other male.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

In a acute dermal irritation study with rabbits erythema and edema as well as necrotic patches were observed in all of the animals with signs of irritation being present at the end of the observation period in three of the ten animals tested. In conclusion the test item was evaluated to be skin irritating.

Executive summary:

The study was designed to assess the acute dermal toxicity of calcium cyanamide, technical grade, following a single dose onto rabbit skin. The test substance was applied as supplied, moistened sufficiently with distilled water to ensure good contact with the skin. A preliminary study (trial test) was performed in one male and one female rabbit using 2 g/kg bw of test substance. Animals were observed for 5 days after dosing and results indicated that the acute median lethal dose of the test substance was > 2g /kg bw. For the main study, a group of ten rabbits (5 male and 5 female) were treated at 2 g/kg bw of calcium cyanamide. One day prior to treatment, hair was removed from the dorso-lumbar region with electric clippers exposing an area equivalent to 10% of the total body surface. No shaving or chemical depilation was used. The test substance was spread evenly over the prepared skin and was then covered with gauze which was held in place with impermeable dressing encircled firmly around the trunk. At the end of the 24 hour exposure period, the dressings were carefully removed and the treated area decontaminated by washing with warm water and blotting with absorbent paper. Animals were observed for skin irritation and clinical signs for 14 days after dosing. All animals of the main study were killed on Day 15 by an intravenous overdose of phenobarbitone sodium and were subjected to macroscopic post mortem examination.

There were no death and no clinical signs of systemic toxicity observed throughout the study period. Erythema and edema as well as necrotic patches were observed in all of the animals with signs of irritation being present at the end of the observation period in three of the ten animals tested.

A slightly lower bodyweight gain was recorded for one female on Day 15 and two males showed cysts on the surface of the kidney at terminal autopsy. All other animals were without findings regarding bodyweight and post mortem examination. In conclusion the test item was evaluted to be skin irritating.