Ashes (residues), coal

Endpoint summary

Description of key information

Ashes (residues) are not irritating to the skin and eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 Jan 2008 - 14 Jan 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Breeding farm BioTest s.r.o., Konárovice, 281 25, Czech Republic
- Age at study initiation: 4-5 months
- Weight at study initiation: 2.8-3.2 kg
- Housing: individually in cages without bedding in a conventional animal room
- Diet (e.g. ad libitum): pelleted standard diet TM-MAK 1 for rabbits and guinea-pigs ad libitum, made by Bergman, Kocanda Mill, 252 42 Jesenice u Prahy
- Water (e.g. ad libitum): drinking tap water ad libitum
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-23
- Humidity (%):30-70
- Air changes (per hr): ca. 15
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 07 Jan 2008 To: 14 Jan 2008

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied:0.5 g

Duration of treatment / exposure:

Initial test: 3 min, 1 and 4 h
Confirmatory test: 4 h

Observation period:

Initial and confirmatory tests: 1, 24 , 48, 72 h

Number of animals:

3 animals (1 female and 2 males)

Details on study design:

TEST SITE
- Area of exposure: 6 x 6 cm
- % coverage: 10
- Type of wrap if used: The test substance was covered by gauze patch, foil and cellulose cotton and held in place with non-irritating tape (Spofaplast)


REMOVAL OF TEST SUBSTANCE
- Washing: At the end of each exposure period the patch was removed and remaining sample was washed off with water.
- Time after start of exposure: 3 min, 1 and 4 h


SCORING SYSTEM: Draize scores

INITIAL TEST:
- Test substance was applied to one animal (rabbit No. 1). Skin reaction was evaluated after 3 min, 1 and 4 h. At 4 h exposure, very slight erythema was observed. After 4-hour exposure, rabbit No. 1 was evaluated for skin reactions according to standard time schedule (24, 48 and 72 h).

CONFIRMATORY TEST:
- Because in the initial test no skin irritation was observed, two additional animals (rabbits No. 2 and 3) were used to confirm the negative response. One patch was applied to each of 2 animals for an exposure period of 4 hours. Skin reactions were evaluated after patch removal at 1, 24, 48 and 72 h post-application.

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of 3 animals

Time point:

other: 1 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

edema score

Basis:

mean

Remarks:

of 3 animals

Time point:

other: 1 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of 3 animals

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

edema score

Basis:

mean

Remarks:

of 3 animals

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of 3 animals

Time point:

48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

edema score

Basis:

mean

Remarks:

of 3 animals

Time point:

48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of 3 animals

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

edema score

Basis:

mean

Remarks:

of 3 animals

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

In the initial test with one animal, very slight erythema and no edema were observed immediately after a 4 h exposure. No irritant reponses were observed in any animal at any other reading time point.

Other effects:

No symptoms of systemic toxicity were observed.

Interpretation of results:

other: The test substance does not fulfil the requirements to be classified according to CLP (EU-GHS) criteria.

Conclusions:

The test substance, Ashes (residues), was tested for acute dermal irritation/corrosion. Three rabbits were exposed to 0.5 g of the test substance, applied onto the clipped skin for 4 h using a semi-occlusive dressing. Skin reactions were evaluated after patch removal and observations were made at 1, 24, 48 and 72 hours after exposure. No symptoms of systemic toxicity were observed in the animals during the test period. No skin irritation was caused by a 4-hour exposure to the test substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Jan 2008 - 21 Jan 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Breeding farm BioTest, s r.o., Konárovice, 281 25 Czech Republic, RČH CZ 21760152
- Age at study initiation: 4-5 months
- Weight at study initiation: 3.0-3.5 kg
- Housing: individually in metallic cages
- Diet (e.g. ad libitum): Standard pelleted diet TM-MAK 1 for rabbits and guinea pigs (made by Bergman, Mill Kocanda, Jesenice u Prahy) ad libitum
- Water (e.g. ad libitum): drinking tap water ad libitum
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 +/- 3
- Humidity (%): 30-70
- Air changes (per hr): ca. 15
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 14 Jan 2008 To: 21 Jan 2008

Vehicle:

unchanged (no vehicle)

Controls:

other: the untreated eye served as control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.1 g

Duration of treatment / exposure:

24 h

Observation period (in vivo):

1, 24, 48 , 72 h

Number of animals or in vitro replicates:

3 males

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing: the treated eye was rinsed with water.
- Time after start of exposure: 24 h


SCORING SYSTEM: Draize scores


TOOL USED TO ASSESS SCORE: fluorescein

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

out of 3 animals

Time point:

other: 1 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 24 h

Irritation parameter:

iris score

Basis:

mean

Remarks:

out of 3 animals

Time point:

other: 1 h

Score:

0

Max. score:

2

Reversibility:

fully reversible within: 24 h

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

out of 3 animals

Time point:

other: 1 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 24 h

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

out of 3 animals

Time point:

other: 1 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 24 h

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

out of 3 animals

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

iris score

Basis:

mean

Remarks:

out of 3 animals

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

out of 3 animals

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

other: not applicable

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

out of 3 animals

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

Clinical examination of eye

Rabbit No. 1:
1 hour: Conjunctivae - some blood vessels hyperaemic (injected)
24 hours: No alterations
48 hours: No alterations
72 hours: No alterations

Rabbit No. 2:
1 hour: Conjunctivae - some blood vessels hyperaemic (injected), Chemosis - some swelling above normal
24 hours: No alterations
48 hours: No alterations
72 hours: No alterations

Rabbit No. 3
1 hour: Conjunctivae - some blood vessels hyperaemic (injected)
24 hours: No alterations
48 hours: No alterations
72 hours: No alterations

Other effects:

No signs of systemic intoxication were observed.

Interpretation of results:

other: The test substance does not fulfil the requirements to be classified according to CLP (EU-GHS) criteria.

Conclusions:

The following changes were observed in the treated eyes at 1 h post-application: some blood vessels were hyperaemic (injected) in all animals, and in one animal, some swelling above normal was noted. At 24, 48 and 72 h after application no signs of eye irritation were observed. No clinical signs of systemic intoxication were detected. It was concluded that the test substance is not irritating to the eye of rabbits.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

Ashes (residues) were tested for acute dermal irritation/corrosion according to OECD guideline 404 and complying with GLP. Three albino rabbits were exposed to 0.5 g of test substance, applied onto the clipped skin for 4 hours using a semi-occlusive dressing. Skin reactions were evaluated after patch removal and observations were made at 1, 24, 48 and 72 hours after exposure. The test substance was applied first on the skin of one rabbit, in which very slight erythema was observed upon removal of the patch after the 4-hour exposure. In a confirmatory test, two more rabbits were used. No evidence of irritation/corrosion effects was observed on the skin and no other signs of intoxication were seen. The mean erythema and edema scores over 24, 48 and 72 h were both 0 for all three animals (ČEZ Energetické produkty, 2008, key).

In another study, the skin irritation/corrosion potential of slag derived from coal combustion was tested in accordance to OECD guideline 404. The shaved skin of 3 male and 3 female New Zealand White rabbits was exposed to 0.5 mL of the test material for 4 hours. Skin reactions were assessed 1, 24, 48 and 72 hours after removal of the test substance. In none of the animals skin reactions were noted. The mean erythema and edema scores over 24, 48 and 72 h were both 0 for all animals (Iberdrola S.A., 2009).

In an earlier study, conducted prior to implementation of GLP and following a protocol similar to OECD guideline 404, three fly ash samples collected at a coal combustion power plant by means of different filter techniques were tested for primary skin irritating properties in albino rabbits. An amount of 0.3 g of undiluted test material was applied onto the clipped skin of 12 rabbits (6 animals with intact, 6 with abraded skin) for 24 h under an occlusive patch. Skin reactions were assessed upon patch removal and 48 h later (72 h post-application). There were no significant differences between reactions of the intact skin and those of the abraded skin. At 24 h post-application (patch removal), all three fly ash samples induced very light erythema (Draize score 1) in 3, 5 and 8 out 12 animals, respectively, depending on the fly ash sample tested. At the 72-h reading, no abnormalities were observed (Kema, 1982).

In support of these findings, data available on Fluidized Bed Combustion (FBC) Fly Ash was also taken into account by means of read-across. FBC Fly Ash differs from Ashes (residues) only in regard to composition, presenting a higher CaO content (total CaO: 19.43%; free CaO: 8.41%). 

FBC Fly Ash was tested for acute dermal irritation/corrosion in three rabbits exposed to 0.5 g of the test substance, which was applied onto the clipped skin for 4 h using a semi-occlusive dressing. Skin reactions were evaluated after patch removal and observations were made at 1, 24, 48 and 72 hours after exposure. No symptoms of systemic toxicity were observed in the animals during the test period. No skin irritation was caused by a 4-hour exposure to the test substance. The mean erythema and edema scores over 24, 48 and 72 h were both 0 for all three animals (Stowarzyszenie Polska Unia Ubocznych Produktow Spalania, 2009).

In vitro skin irritation/corrosion studies were also available, supporting the findings described above.

Ashes (residues) – Fly ash and Ashes (residues) – Slag were tested for in vitro skin irritation in the human epidermal model EpiDerm™ in compliance with GLP and according to an OECD and EU draft proposal for a new test guideline. The test material (25 mg) was applied directly to cultured skin tissue previously moistened with 25 µL sterile PBS. After a 60-min treatment, the tissue replicates were rinsed and incubated under tissue culture conditions for 42 h. Thereafter, an MTT cell viability assay was performed. The relative cell viability was calculated as percent of the mean viability of the negative control tissues. The average cell viability of tissues treated with Ashes (residues) – Fly ash and Ashes (residues) – Slag was 97.4 and 106.3%, respectively. Thus, under the test conditions of these studies, the test materials are not considered to be skin irritants (ČEZ Energetické produkty, 2009).

In order to investigate whether free lime content has an influence on skin irritation/corrosion, three samples of Ashes (residues), coal containing different amounts of free CaO (1.6, 1.9 and 6.6%) were tested for in vitro skin corrosion, using an artificial three-dimensional model of human skin (EST 1000 from CellSystems® Biotechnology GmbH) following a protocol in accordance with OECD guideline 431 and GLP. The ash samples (25 mg) were moistened with deionised water (50 µL) and administered topically to the human skin model (0.6 cm²) at 25 µL/cm². Two exposure times of 3 min and 1 h were employed. Deionised water and 8 N KOH were used as negative and positive control substances, respectively. The cell viability was assessed by means of the MTT reduction assay, and expressed as percentage of the negative control. The pH value of the ash suspension in water was 12.12, 12.52 and 12.49 for the ash samples containing 1.6, 1.9 and 6.6% free CaO, respectively. The viability of the treated cells at the 3 min incubation was 103.1, 94.4 and 92.3%, respectively. At the 1 h incubation, the corresponding cell viability values were 100.8, 92.7 and 92.7%, respectively. These values were well above the cut-off percentage cell viability values distinguishing corrosive from non-corrosive test items of < 50% and < 15% for a 3 min or 1 h treatment, respectively. The viability of cells treated with the positive reference item 8 N KOH were 47.4% (3 min incubation) and < 0.1% (1 h incubation) of the negative controls and, hence, below the cut-off values. Hence, 8 N KOH caused pronounced skin corrosion. Under the test conditions described, the Ashes (residues), coal samples containing different amounts of free lime tested at two exposure times of 3 minutes or 1 hour were all non-corrosive to skin in experiments with an artificial three-dimensional model of human skin (Evonik Degussa GmbH, 2010).

In conclusion, the available data indicate that Ashes (residues), coal containing up to 6.6% free CaO are not corrosive or irritating in vitro. The available in vivo studies also indicate that both Ashes (residues), coal and the analogue substance Fluidized Bed Combustion (FBC) Fly Ash containing 8.41% free CaO are not irritating to the skin. Therefore, no hazard is identified.

 

Eye irritation

Ashes (residues) were tested for eye irritation/corrosion in albino rabbits in a study performed according to the OECD guideline 405 and complying with GLP. The test material (0.1 g) was applied into the conjunctival sac of one eye and removed after 24 h by rinsing with water; the other eye served as control. The eyes were examined and scored 1, 24, 48 and 72 h after application. Initially, one animal was tested only, in which no corrosive effects were observed. The negative response was confirmed using two additional animals. Conjunctivae and chemosis effects were observed in all animals at 1 h post-application: some blood vessels were hyperaemic (injected) and in one animal some swelling above normal was noted. No signs of eye irritation were observed at the subsequent readings. The average cornea, iris, conjunctivae and chemosis scores over 24, 48, and 72 h were all 0 for all animals (ČEZ Energetické produkty, 2008, key).

In an earlier non-GLP study similar to OECD guideline 405, three fly ash samples collected at a coal combustion power plant by means of different filter techniques were examined for eye irritating properties in New Zealand White rabbits. Each fly ash sample was tested in 6 rabbits by applying an amount of 0.1 g into the conjunctival sac of one eye without washing at a later time point. The eyes were examined and scored 24, 48 and 72 h as well as 7 days after application. After 24 h the eye effects caused by fly ash sample 1 consisted of slight opacity of the cornea in one rabbit, moderate redness and slight to moderate swelling of the conjunctivae in all 6 rabbits. After 48 h also slight iritis was observed in one rabbit. In the course of the 7-day observation period, these lesions recovered partly. After 7 days slight redness of the conjunctivae was still observed in four out of six rabbits and slight swelling of the conjunctivae in one out of six rabbits. Fly ash samples 2 and 3 caused eye effects after 24 h generally consisting of slight redness and slight swelling of the conjunctivae. In addition, one rabbit showed slight iritis by sample 2. In the course of the 7-day observation period, these lesions cleared up completely (Kema, 1983).

Data available on Fluidized Bed Combustion (FBC) Fly Ash was also taken into account by means of read-across. FBC Fly Ash differs from Ashes (residues), coal only in regard to composition, presenting a higher CaO content(total CaO: 19.43%; free CaO: 8.41%).

For justification on read-across from FBC Fly Ash to Ashes (residues), coal, refer to Appendix I (Reporting Format for the analogue approach).

FBC Fly Ash was tested for eye irritation/corrosion in albino rabbits in a GLP-compliant study performed according to the OECD guideline 405 and EU method B.5. The test material (0.1 g) was applied into the conjunctival sac of one eye without washing at a later time point; the other eye served as control. The treated eyes were examined and scored 1, 24, 48 and 72 h after application. Initially, one animal was tested only, in which no corrosive effects were observed. The response was confirmed using two additional animals. Conjunctivae and chemosis effects were observed in all animals at 1 h post-application: Diffuse beefy red conjunctivae and swelling with lids more than half-closed were noted. At the subsequent readings, irritation effects recovered time-dependently. The mean conjunctivae and chemosis scores over 24, 48 and 72 h for each individual animal were 1.3/0.7/1.7 and 2.0/1.0/1.7, respectively. In the first rabbit tested, irritant effects were fully reversible within 12 days, while in the other two rabbits effects were fully reversible within 72 and 96 h, respectively (Stowarzyszenie Polska Unia Ubocznych Produktow Spalania, 2009).

 In conclusion, the available data indicate that both Ashes (residues), coal and the analogue substance Fluidized Bed Combustion (FBC) Fly Ash containing 8.41% free CaO induce no or only minor reversible effects on the eye, which are not sufficient for classification. Therefore, Ashes (residues), coal are considered not irritating to the eye and no hazard is identified.

Justification for classification or non-classification

The available data on the skin and eye irritation potential of ashes (residues) is conclusive but not sufficient for classification.