Zinc iron chromite brown spinel

Endpoint summary

Description of key information

Acute oral toxicity: LD50 > 2000 mg/kg bw (OECD 423 (1996); Non-GLP compliant)
Acute inhalation toxicity: LC50 (rats; 4 hours) > 5.06 mg/L air (actual concentration) (OECD 436 (2009); GLP compliant)

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Comparable to guideline study reliable without restrictions Minor deviations from the guideline: - the lot/batch no. was missing. - the humidity (80%) was slightly higher than 70 %. - after treatment of one sex, the other sex should not be treated until one is confident of survival of the previously dosed animals. In this study males and females were treated on the same day. - age and source of the animals were not stated. - details of food and water quality (including type/source, water source) were missing.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

adopted 1996-03-22

Deviations:

yes

Remarks:

, please refer to "Rationale for reliability incl. deficiencies" above

GLP compliance:

no

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS - Sprague-Dawley rats (CFY)
- Age at study initiation: young and healthy
- Weight at study initiation: males: 128 g - 137 g; females: 119 g - 120 g
- Fasting period before study: animals fasten during the previous night; after 3 hours of administration, feeding was restored.
- Housing: groups of three; Makrolon cages (48 X 27X 20 cm), brand Tecniplast, with wooden bedding; cleaning by means of changing wooden bedding
- Diet (ad libitum): diet for experimental rats, provided by an authorized provider
- Water (ad libitum): tap water
- Acclimation period: 7 days

At arrival at the Unit, rats went through a health control.

ENVIRONMENTAL CONDITIONS
- Temperature: 21 °C (+/- 2°C)
- Relative humidity: 55% (+/- 25%)
- Air: renewed 15 times per hour and prefiltered at 5 µm
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 2 mL of the diluted sample per 100 grams of alive weight

DOSAGE PREPARATION: 2000 mg of sample were diluted in 20 mL of distilled apirogenic water. Sample was vigorously stirred before administration.

CLASS METHOD
- Rationale for the selection of the starting dose: the available information suggested that the sample is little toxic and the limit test was performed.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3 males / 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: individual weight control was performed at the beginning of the study, before administration, after 7 days of administration and at the end of the study or in case of death, right after death. A general clinical examination was performed every working day during which modifications were observed and noted, among other: skin, hair, eyes, mucosity, respiratory track, circulatory system, central and autonomous nervous system, motion activity and behavioural lines of action. With special care for: shaking, convulsions, salivation, diarrhea, lethargy, sleep and coma.
During the first day regular observations were performed and the following days the animals were observed at least once daily for 14 days.
The observed signs of toxicity were observed at the moment of appearance and also the time of recovery.
- Necropsy of survivors performed: yes; after the study, the surviving animals were sacrificed by means of a humanitarian method (cervical dislocation). All the animals in the study were subject to macroscopic necropsy. Macroscopic pathology were noted for each animal.

Statistics:

not applicable

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived until the end of the 14 days of observation.

Clinical signs:

other: Neither abnormal effects nor any toxicity signs that could be attributed to the sample were observed.

Gross pathology:

There were no relevant macroscopic changes observed in any of the animals.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LD50 (male and female rats) > 2000 mg/kg bw
According to the EC-Commission directive 67/548/EEC and its subsequent amendments, the test substance is not classified as acute toxic via the oral route.
According to the EC-Regulation 1272/2008 and subsequent regulations, the test item is not classified as acute toxic via the oral route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

The study fulfils the requirements for acute oral toxicity under REACH (Regulation (EC) 1907/2006).

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-07-17 to 2012-09-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study reliable without restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

adopted 2009-09-07

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-11-12

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at study initiation: males: approx. 8 weeks; females: approx. 9 weeks
- Weight at study initiation: males: 241 - 254 g; females: 213 - 242 g
- Fasting period before study: feeding was discontinued approx. 16 hours before exposure; only tap water was then available ad libitum.
- Housing: granulated textured wood (Granulat A2, J. Brandenburg, 49424 Goldenstedt, Germany) was used as bedding material for the cages. During the 14-day observation period, the animals are kept by sex in groups of 2 - 3 animals in MAKROLON cages (type III plus).
- Diet: commercial diet, ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany)
- Water (ad libitum): drinking water
- Acclimation period: at least 5 adaptation days

The animals were randomised before use. They were acclimatised to the test apparatus for approx. 1 hour on 2 days prior to testing. The restraining tubes did not impose undue physical, thermal or immobilization stress on the animals.

ENVIRONMENTAL CONDITIONS
- Temperature: 22°C± 3°C (maximum range)
- Relative humidity: 55% ± 15% (maximum range)
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: the study was carried out using a dynamic inhalation apparatus (RHEMA-LABORTECHNIK, 65719 Hofheim/Taunus, Germany) (air changes/h (≥ 12 times)) with a nose-only exposure of the animals according to KIMMERLE & TEPPER. The apparatus consists of a cylindrical exposure chamber (volume 40 L) which holds the animals in pyrex tubes at the edge of the chamber in a radial position.

- System of generating particulates/aerosols: the dust of the test material was generated with a rotating brush dust generator (RBG 1000, PALAS GmbH Partikel und Lasermesstechnik, 76229 Karlsruhe, Germany).
The generator was fed with compressed air (5.0 bar) from a compressor (ALUP Kompressorenfabrik, 73257 Köngen, Germany) (air was taken from the surrounding atmosphere of the laboratory room and filtered using an in-line disposable gas-filter).
At the bottom of the exposure chamber, the air was sucked off at a lower flow rate than it was created by the dust generator in order to produce a homogenous distribution and a positive pressure in the exposure chamber (inflow 900 L/h, outflow 800 L/h).
A manometer and an air-flow meter (ROTA Yokogawa GmbH & Co. KG, 79664 Wehr/Baden, Germany) were used to control the constant supply of compressed air and the exhaust, respectively. Flow rates were checked hourly and corrected if necessary.
The exhaust air was drawn through gas wash-bottles.

- Method of particle size determination: an analysis of the particle size distribution was carried out twice during the exposure period using a cascade impactor according to MAY (MAY, K. R. Aerosol impaction jets, J.Aerosol Sci. 6, 403 (1975), RESEARCH ENGINEERS Ltd., London N1 5RD, UK).
The dust from the exposure chamber was drawn through the cascade impactor for 5 minutes at a constant flow rate of 5 L/min. The slides were removed from the impactor and weighed on an analytical balance (SARTORIUS, type 1601 004, precision 0.1 mg). Deltas of slides’ weight were determined.
The mass median aerodynamic diameter (MMAD) was estimated by means of non-linear regression analysis. The 32 µm particle size range and the filter (particle size range < 0.5 µm) were not included in the determination of the MMAD in order not to give undue weight to these values.
The Geometric Standard Deviation (GSD) of the MMAD was calculated from the quotient of the 84.1%- and the 50%-mass fractions, both obtained from the above mentioned non-linear regression analysis.
In addition, a sample of approx. 10 g test material was taken from the exposure chamber to determine the median physical particle size with a Malvern Mastersizer 2000 by My-Tec, 91325 Adelsdorf, Germany. This determination was non-GLP.

- Temperature, humidity, pressure in air chamber, oxygen content, carbon dioxide content: the oxygen content in the inhalation chamber was 21%. It was determined at the beginning and at the end of the exposure with a DRÄGER Oxygen-analysis test set (DRÄGER Tube Oxygen 67 28 081). Carbon dioxide concentration did not exceed 1%.
Temperature (21.4°C ± 0.1°C (main study and satellite group)) and humidity 59.5% ± 0.6% (main study) or 63.9% ± 0.6% (satellite group)) were measured once every hour with a climate control monitor (testo 175-HZ data logger).

The whole exposure system was mounted in an inhalation facility to protect the laboratory staff from possible hazards.

Exposition started by locating the animals into the exposure chamber after equilibration of the chamber concentration for at least 15 minutes (t95 approximately 8 minutes).

Before initiating the study with the animals, a pre-test was carried out with the exposure system in order to verify that under the experimental settings chosen, the limit concentration of 5 mg/L air could be achieved by gravimetric analysis.

The tests with the main study animals and the recovery animals were conducted in the same inhalation chamber but on different days. Between the exposure times the chamber was cleaned carefully.

TEST ATMOSPHERE
- Brief description of analytical method used: the actual dust concentration in the inhalation chamber was measured gravimetrically with an air sample filter (Minisart SM 17598 0.45 µm) and pump (Vacuubrand, MZ 2C(Membrane Pump, Vacuubrand GmbH + Co. KG, 97877 Wertheim/Main, Germany)) controlled by a rotameter. Dust samples were taken once every hour during the exposure. For that purpose, a probe was placed close to the animals' noses and air was drawn through the air sample filter at a constant flow of air of 5 L/min for 1 minute. The filters were weighed before and after sampling (accuracy 0.1 mg).
Individual chamber concentration samples did not deviate from the mean chamber concentration by more than 20%
- Samples taken from breathing zone: yes

TEST ATMOSPHERE
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):
Main study: 4.760 µm (GSD: 3.04 )
Satellite group: 4.536 µm (GSD: 3.05)
No smaller MMAD and GSD could be obtained with the test item supplied.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see above ("Details on inhalation exposure")

Duration of exposure:

4 h

Concentrations:

Main study (limit test):
- actual concentration: 5.06 ± 0.02 mg/L air
- nominal concentration: 8.33 mg/L air
Satellite group:
- actual concentration: 5.06 ± 0.03 mg/L air
- nominal concentration: 8.33 mg/L air

No. of animals per sex per dose:

Main study (limit test):
3 males / 3 females
Satellite group:
3 males / 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 24 hours (satellite group) and 14 days (main study)
- Frequency of observations and weighing: during and following exposure, observations were made and recorded systematically; individual records were maintained for each animal. Careful clinical examinations were made at least twice daily until all symptoms subsided, thereafter each working day. Observations on mortality were made at least once daily (in the morning starting on test day 2) to minimize loss of animals to the study, e.g. necropsy or refrigeration of those animals found dead and isolation or human sacrifice of weak or moribund animals.
Cageside observations included, but were not limited to: changes in the skin and fur, eyes, mucous membranes, respiratory, circulatory, autonomic and central nervous system, as well as somatomotor activity and behaviour pattern.
Particular attention was directed to observation of tremor, convulsions, salivation, diarrhoea, lethargy, sleep and coma. The animals were also observed for possible indications of respiratory irritation such as dyspnoea, rhinitis etc. The measurement of rectal temperatures might provide supportive evidence of reflex bradypnea or hypo-/hyperthermia related to treatment or confinement.
Individual weights of animals were determined once during the acclimatisation period, before and after the exposure on test day 1, on test days 3, 8 and 15. Changes in weight were calculated and recorded when survival exceeded one day. At the end of the test, all animals were weighed and sacrificed.
- Necropsy of survivors performed: yes
Necropsy of all main study and satellite animals (3 + 3 males and 3+3 females) was carried out and all gross pathological changes were recorded:
- Satellite animals: necropsy at 24 hours after cessation of exposure, as this is likely to be the time at which any signs of respiratory irritation would have manifested;
- Main study animals: necropsy at the end of the 14-day observation period.
The following organs of all animals were fixed in 10% (nose, i.e. head without brain, eyes and lower jaw) or 7% (larynx, trachea, lungs) buffered formalin for possible histopathological examination. No further organs were preserved.

Statistics:

Since no animal died prematurely, the calculation of an LC50 was not required.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.06 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No animal died prematurely.

Clinical signs:

other: Under the present test conditions, a 4-hour inhalation exposure to zinc iron chromite brown spinel (Pigment brown 33) at a concentration of 5.06 mg/L air revealed slight ataxia and slight dyspnoea (reduced frequency of respiration with increased volume) u

Body weight:

One female animal of the main study appeared to be reduced in body weight gain at the end of the study.

Gross pathology:

Dark discoloured lungs were observed in all animals of the main study (14-day sacrifice).

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LC50 (rats; 4 hours) > 5.06 mg/L air (actual concentration)
According to the EC-Commission directive 67/548/EEC and its subsequent amendments, the test substance is not classified as acute toxic via the inhalation route.
According to the EC-Regulation 1272/2008 and subsequent regulations, the test item is not classified as acute toxic via the inhalation route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

The study fulfils the requirements for acute inhalation toxicity under REACH (Regulation (EC) 1907/2006).

Additional information

Acute oral toxicity

One reliable study described in Alvarez Genoher (2001; OECD 423 (1996); Non-GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The LD50 was determined to be greater than 2000 mg/kg bw.

Acute inhalation toxicity

One reliable study described in Haferkorn (2013; OECD 436 (2009); GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The LC50 was determined to be greater than 5.06 mg/L air (actual concentration).

Justification for selection of acute toxicity – oral endpoint
One reliable study described in Alvarez Genoher (2001; OECD 423 (1996); Non-GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The LD50 was determined to be greater than 2000 mg/kg bw.

Justification for selection of acute toxicity – inhalation endpoint
One reliable study described in Haferkorn (2013; OECD 436 (2009); GLP compliant) is considered to be reliable without restrictions and is used as key study for this endpoint. The LC50 was determined to be greater than 5.06 mg/L air (actual concentration).

Justification for classification or non-classification

Acute oral toxicity

Reference Alvarez Genoher (2001) will be used as key study for acute oral toxicity and will be used for classification.

The LD50 was determined to be greater than 2000 mg/kg bw. Thus, according to regulation (EC) 1272/2008 and subsequent amendments the substance is not classified.

Specific target organ toxicant (STOT) - single exposure: oral

The classification criteria according to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, oral are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, oral for a Category 1 classification (C≤ 300 mg/kg bw) and at the guidance value, oral for a Category 2 classification (2000 mg/kg bw≥C > 300 mg/kg bw). No classification required.

Acute inhalation toxicity

The reference Haferkorn (2013) is considered as the key study for acute inhalation toxicity of zinc iron chromite brown spinel and will be used for classification. Male and female rats were exposed to 5.06 mg/L air (main study, limit test, observation period 14 days) or 5.06 mg/L air (satellite group; observation period 24 hours) for 4 hours. No mortality occurred. The LC50 is > 5.06 mg/L air.

The classification criteria according to regulation (EC) 1272/2008 as acutely toxic are not met since the ATE is above 5.0 mg/L, hence no classification required.

Specific target organ toxicant (STOT) - single exposure: inhalation

The classification criteria according to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, inhalation (dust/mist/fume) are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, inhalation (dust/mist/fume) for a Category 1 classification (C≤ 1 mg/L/4h). Based on the outcome of the limit test on acute inhalation toxicity (0 animals of 6 animals died at a concentration of 5.06 mg/L/4h and no systemic or local effects were observed) it can safely be assumed that no classification for Category 2 (5.0 ≥C > 1.0 mg/L/4h) is required.