Copper

Endpoint summary

Description of key information

Several high quality criteria studies (reliability 1 or 2) on coated copper flakes and several copper compounds are available from the VRA. 
These have been evaluated by the Competent authorities for Existing Substances and Biocides.  Some additional studies (reliability 1-3) on “coated copper flakes” were submitted thereafter and have been discussed in more details  in the chemical safety report (section 5.2.1.2 and section 5.2.3). 
Only high quality criteria (reliability 1 or 2) studies relevant to the hazard assessment of coated copper flakes and copper (powder and massive forms) were retained for the CSR. 
The VRA provides additional, lower quality studies as well as studies specific to other soluble copper compounds. If not pivotal to this copper REACH dossier, they are described in the copper VRA but not further discussed below.
For the hazard profile of copper powder, information on solubility, bioavailability and bioaccessibility (sections 5.1) are combined with the hazard profile of copper compounds and coated copper flakes in a read-across approach to assess its potential hazards .

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:

weight of evidence

Study period:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD Guideline 423 and EU Method B.1 tris Considering the lack of information on purity and particle size, a reliablility of 2 is assigned

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Source: charles river (UK) Ltd, Margate, Kent, UK
At the start of the study the males weighed 271 to 299 g and the females weighed 198 to 218g, and were approximately eight weeks of age.
3 animals per group

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

the test material was administered orally as a suspension inarachis oil BP.

Doses:

200 and 2000 mg/kg bw
concentration in vehicle: 20 and 200 mg/ml at 200 and 2000 mg/kg bw, respectively
Total volume applied: 10 ml/kg

No. of animals per sex per dose:

A group of three fasted females was treated with 2000 mg/kg bw.
Further groups of 3 male and 3 female fasted animals were treated at a dose level of 200 mg/kg bw.

Control animals:

no

Sex:

male/female

Dose descriptor:

LD50

Effect level:

300 - 500 mg/kg bw

Mortality:

Two animals treated with 2000 mg/kg bw were found dead five days after dosing.
One animal treated with 2000 mg/kg bw was killed in extremis eight days after dosing.
There were no deaths noted at a dose level of 200 mg/kg bw.

Clinical signs:

other: Signs of systemic toxicity noted in animals treated with 2000 mg/kg bw were hunched posture, lethargy, pilo-erection, diarrhoea, decreased respiration rate, laboured respiration, ataxia, pallor of the extremities, emaciation, tiptoe gait and faeces staine

Gross pathology:

abnormalities noted at necropsy of the animals treated with 2000 mg/kg bw that died during the study were abnormally red lungs, dark liver, dark kidneys, copper-coloured material present in the stomach, haemorrhagic gastric mucosa, sloughing of the non-glandular epithelium of the stomach and haemorrhagic small and large intestines.

No abnormalities were noted at necropsy of animals treated with 200 mg/kg bw.

Other findings:

The LD50 of the test material was estimated to be in the range of 300-500 mg/kg bw

Interpretation of results:

harmful

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test material from the manufacturere corresponds to the composition of “ coated copper flakes” .
The acute oral LD50 of the test material in the rat was estimated to be in the range of 300 - 500 mg/kg bw. Coated copper flakes therefore meet the criteria for classification as harmful according to Annex VI of Commission Directive 2001/59/EC. Copper coated flakes should be attributed the symbol Xn: harmful and the Risk Phrase R22: Harmful if swallowed.
The results are considered as applicable to the "coated copper flakes" .

Executive summary:

The test material identity was not provided in details. Considering the information from the reports on the same material, the tested material falls in the composition category of "coated copper flakes" (see– section 1.2), consistent with a biocidal product use (PBD notification was the reason for doing the test).

The acute oral LD50 of the test material in the rat was estimated to be in the range of 300 - 500 mg/kg bw.

The test material meets the criteria for classification as harmful according to Annex VI of Commission Directive 2001/59/EC. The test substance should be attributed the symbol Xn: harmful and the Risk Phrase R22: Harmful if swallowed.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

300 mg/kg bw

Quality of whole database:

High quality

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with Good laboratory Practice and internationally accepted guidelines.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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
- Source: Charles River Laboratories Research Models and Services Germany GmbH. Sandhofer Weg 7, 97633 Sulzfeld, Germany.
- Age at study initiation: Males, approximately 7 weeks. Females, approximately 9 weeks.
- Weight at study initiation: Males, 238 - 262 g. Females, 231 - 245 g.
- Fasting period before study: Feeding was discontinued 16 hours before exposure.
- Housing: Granulated textured wood was used as bedding material for the cages. During the 14-day observation period, the animals were kept by sex in groups of 3 animals in MAKROLON cages (tpe III plus).
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum.
- Acclimation period: At least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 3°C
- Humidity (%): 55% +/- 15%
- Photoperiod (hrs dark / hrs light): 12 hrs dak/12 hrs light.

Route of administration:

inhalation

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Dynamic nose-only inhalation apparatus (RHEMA-LABORTECHNIK, 65719 Hofheim/Taunus, Germany).
- Exposure chamber volume: 40L
- Method of holding animals in test chamber: Animals were held in pyrex tubes at the edge of the chamber in a radial position.
- Source and rate of air: The generator was fed with compressed air (5.0 bar) taken from the surrounding laboratory atmosphere. Air changes 22.5 times per hour.
- Method of conditioning air: Air was filtered using an in-line disposable gas filter.
- System of generating particulates/aerosols: The dust of the test material was generated using a rotating brust dust generator (RBG 1000, PALAS GmbH, Partikel und Lasermesstechnik, 76229 Karlsruhe, Germany).
- Method of particle size determination: Particle size distribution was determined during the exposure period using a cascade impactor.
- Treatment of exhaust air: The exhaust air was drawn through gas wash-bottles.
- Temperature, humidity, pressure in air chamber: The temperature during the exposure period was in the range 21.3 - 21.9°C. Humidity was in the range 60.3 - 64.2%. A positive aire pressure was maintained within the exposure apparatus.. Air flow at the entrance was 900 L/h. Air flow at the exis was 800 L/h.

TEST ATMOSPHERE
- Brief description of analytical method used: The dust inhalation in the inhalation chamber was measured gravimetrically witha n air sample filter and pump controlled by a rotameter. Dust samples were taken once every hour during the exposure. A probe was placed close to the animals' noses and air was drawn through the air sample filter at a constant rate of 5L/minute for 1 minute. The filters were weighed befor and after sampling
- Samples taken from breathing zone: yes.

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: See Table 1.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The MMAD was 3.477 µm (1.24 or 5.11 mg/L). The GSD of the MMADs were calculated as 2.61 or 2.77 (1.24 or 5.11 mg/L).

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: A nominal limit concentration of 5 mg/L was chosen.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetrically determined

Duration of exposure:

4 h

Concentrations:

Gravimetrically determined concentrations (with SD) of 1.24 (±0.03) and 5.11 (±0.02) mg Copper powder KU 7600 Standard Material/L air.

No. of animals per sex per dose:

3 males and 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days.
- Frequency of observations and weighing: Clinical examinations were made at least once daily until all symptoms subsided, thereafter each working day. Observations on deaths were made at least once daily. Individual weight were determined once during acclimatisation, before exposure on day 1, on days 2, 4, 8 and 15.
- Necropsy of survivors performed: yes.
- Other examinations performed: clinical signs, body weight, lung weight.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.11 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: There was no evidence of respiratory tract irritation

Mortality:

none

Clinical signs:

other: A 4-hour inhalation exposure to Copper powder KU 7600 Standard Material at concentrations of 1.24 or 5.11 mg/L air revealed concentration-related slight to moderate ataxia, slight to moderate tremor and slight to moderate dyspnoea (reduced frequency of re

Body weight:

One of three females treated with the low concentration showed a reduced body weight gain at the end of the study compared to the start value (+2.9%). The two other females showed weight gains of +7.1% and +10.0%.
Two of three females treated with the high concentration showed a reduced body weight gain at the end of the study compared to the start value (+2.5% and +3.3%). The remaining female showed a weight gain of +6.1%.

Gross pathology:

Dark or slight grey-stained discoloured lungs were observed in two males at the dose level of 1.24 mg/L or in one male and 1 female at the dose level of 5.11 mg/L.

Other findings:

There was no evidence of respiratory tract irritation

Results are summarized in table 2 (attached)

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study, the 4-hour inhalation LC50 of Copper powder KU 7600 Standard Material is >5.11 mg/L air. No evidence of respiratory tract irritation could be observed. The test material is not classified as dangerous. The LOAEC of 1.24 mg/L was used for deriving a short trom inhalation DNEL

Executive summary:

A GLP-compliant acute inhalation test was carried out in the Sprague-Dawley rats in accordance with OECD Guideline 436.  Groups of 3 males and 3 females were exposed for 4 hours to a dry aerosol of Copper powder KU 7600 Standard Material at gravimetrically determined concentrations of 1.24±0.03 and 5.11±0.02 mg /L air using a dynamic nose-only exposure chamber. The aerosol was generated with the aid of a dry, rotating brush dust generator. The MMAD of particles in the animals’ breathing zone was 3.477 µm. GSDs of the MMADs were 2.61 (1.24 mg/L) or 2.77 (5.11 mg/L).

No mortalities were observed at either exposure concentration.  One of three females from the low concentration group and two of three females from the high concentration group showed reduced body weight gain at the end of the study. A 4-hour inhalation exposure to Copper powder KU 7600 Standard Material at concentrations of 1.24 or 5.11 mg/L air revealed concentration-related slight to moderate ataxia, slight to moderate tremor and slight to moderate dyspnoea (reduced frequency of respiration with increased volume) on test day 1 immediately after end of exposure until 3 hours or until test day 4 in all animals, respectively (3 of 3 male and 3 of 3 female animals, each). In addition, reduced motility was observed in all animals at 5.11 mg/L air 2 to 4 days after exposure. Dark or slight grey-stained discoloured lungs were observed in two males from the 1.24 mg/L group and in one male and one female from the 5.11 mg/L exposure group.

The 4-hour inhalation LC50 of Copper powder KU 7600 Standard Material is >5.11 mg/L air.  No evidence of respiratory tract irritation could be observed.  On this basis the test material is unclassified with regard to acute inhalation toxicity.

Reference 2

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP study according toOECD Guideline 403 Some inportant deficiencies are observed: (1) large difference between the tartget and actual dosis; (2) lack of clear reported dose-response (3)No batch number, nor certificate is provided. No information on impurities is provided - the substance was tested for submission as a biocidal products and the addition of eg zinc stearates are not uncommon (see sample identity and characteristics from same producer in sections physico-chemical properties) but this was not reported.

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

at the start of the study animals were approximately 8 to 10 weeks old; males weighed 267 to 315 g and females weighed 192 to 265g.

Route of administration:

inhalation

Type of inhalation exposure:

nose only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

4h exposure duration
14 days post exposure period

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Group 1: 1.12 mg/l (mean achieved atmospheric concentration)
Group 2: 0.59 mg/l (mean achieved atmospheric concentration)
Group 3: 1.68 mg/l (mean achieved atmospheric concentration)
Group 4: 0.84 mg/l (mean achieved atmospheric concentration)
Group 5: 2.13 mg/l (mean achieved atmospheric concentration)

No. of animals per sex per dose:

groups of 5 (females or males) or 10 rats (females + males)

Control animals:

no

Sex:

male/female

Dose descriptor:

LC50

Effect level:

1.03 mg/L air (analytical)

95% CL:

0.692 - 1.55

Exp. duration:

4 h

Sex:

male

Dose descriptor:

LC50

Effect level:

0.733 mg/L air (analytical)

95% CL:

0.609 - 0.838

Exp. duration:

4 h

Sex:

female

Dose descriptor:

LC50

Effect level:

1.67 mg/L air (analytical)

95% CL:

1.41 - 1.99

Exp. duration:

4 h

Mortality:

4/5, 2/5, 5/10, 4/5 and 1/5 animals died at 2.13, 1.68, 1.12, 0.84 and 0.59 mg/l, respectively. All deaths occurred within 24h of exposure to the test substance.

Clinical signs:

other: see 'remarks on results'

Body weight:

reduced bodyweight gain or weight loss was noted in most surviving animals during the first week of the recovery period. All surviving animals showed an overall body weight gain at the end of the treatment period.

Gross pathology:

Three rats (one surviving male and one surviving female from group 1, and 1 surviving male from group 4) were free from abnormal gross necropsy findings.
Gross necropsy of the remaining premature decendents and surviving animals showed abnormal findings in the lungs (enlarged, dark patches, pale, pale patches, dark foci, fluid filled, discolouration, haemorrhagic, abnormally dark) and less frequently in the liver (patch pallor), small intestine (qaseous distension, dark contents) and large intestine (gaseous distension).

Clinical signs:

DOSE GROUP 5 - 2.13 MG/L:

During exposure, decreased respiratory rate, laboured respiration and wet fur were noted in all animals and there were instances of increased respiratory rate and fur staining by the test material. On removal from the chamber, animals showed decreased or increased respiratory rate, laboured respiration, hunched posture, piloerection, fur staining by the test material and wet fur and there were instances of pallor of the extremities, ataxia, noisy respiration and cyanosis. One hour after removal, a slight worsening in the condition of the surviving animals was observed. Post exposure, the surviving animal recovered relatively quickly to appear normal from day 4.

DOSE GROUP 3- 1.68 MG/L:

during exposure, decreased respiratory rate, fur staining by the test material and wet fur were noted in all animals and laboured respiration was common. On removal from the chamber, surviving animals showed decreased or increased respiratory rate, noisy respiration, ataxia, hunched posture, piloerection, fur staining by the test material and wet fur and there were instances of laboured respiration, pallor of the extremities, and ptosis. One hour after removal, a deterioration in the condition of the animals was observed, with hypothermia now observed for all animals. Post exposure, animals made a steady recovery though clinical signs such as hunched posture and noisy respiration persisted. Two animals appeared asymptomatic from day 6 but noisy respiration persisted throughout the observation period for the other survivor.

DOSE GROUP 1 - 1.12 MG/L:

during exposure, decreased or increased respiratory rate and wet fur were noted in all animals and laboured respiration and fur staining by the test material were common. On removal from the chamber, surviving animals showed decreased respiratory rate, noisy respiration, hunched posture, piloerection, fur staining by the test material and wet fur, whilst ataxia, pallor of the extremities,cyanosis, lethargy and ptosis were frequently seen. One hour after removal, little change in the condition of the surviving males was observed, whilst the condition of the female animals had deteriorated slightly.

Post exposure, animals made a steady recovery though clinical signs such as hunched posture and noisy respiration persisted. The female animals appeared asymptomatic from day 8 but noisy respiration persisted until day 12 for the surviving male.

DOSE GROUP 4 - 0.84 MG/L

during exposure, decreased or increased respiratory rate and wet fur were noted in all animals and laboured respiration and fur staining by the test material were common. On removal from the chamber, surviving animals showed increased respiratory rate, laboured and noisy respiration, pallor of the extremities, ptosis, hunched posture, piloerection, fur staining by the test material and wet fur and ataxia was recorded for most of the animals. One hour after removal, little change in the condition of the animals was observed.

Post exposure, the sole surviving animal recovered quickly to appear normal from day 3.

DOSE GROUP 2 - 0.59 MG/L

during exposure, decreased or increased respiratory rate and wet fur were noted in all animals and there was a single instance of laboured respiration. on removal from the chamber, animals showed decreased or increased respiratory rate, noisy respiration, hunched posture, piloerection, fur staining by the test material and wet fur and there were instances of laboured respiration, ataxia and cyanosis. One hour after removal, three animals showed slight signs of recovery whilst the condition of the other two had deteriorated slightly.

Post exposure, respiratory observations diminished over several days leaving hunched posture as the only clinical sign in surviving animals. One animal appeared normal from day 6 and all animals were asymptomatic from day 8.

Signs of wet fur, hunched posture, piloerection and red/brown staining around snout and/or eyes are commonly seen in animals for short periods on removal from the chamber following 4 -hour inhalation studies. These observations are considered to be associated with the restraint procedure and, in isolation, are not indicative of toxicity.

Interpretation of results:

harmful

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute inhalation LC50 (4h) was found to be 1.03 mg/l (males and females). The study is considered as having a low quality

The test sample characteristics correspond to "coated copper flakes". The results are thus applicable to "coated copper flakes"

Executive summary:

The acute inhalation LC50 (4h) was found to be 1.03 mg/l.

therefore, copper powder meets the criteria for classification as harmful according to Annex VI of Commission Directive 2001/59/EC. The test substance should be attributed the symbol Xn: 'harmful', and the Risk Phrase R:20 'Harmful by inhalation'.

The test sample characteristics corresponds to "coated copper flakes"

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

5 110 mg/m³ air

Quality of whole database:

High quality

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD Guideline 402 and EU method B3 The test material has no batch number and no information on purity nor particle size distribution

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Qualifier:

according to guideline

Guideline:

other: Commission Directive 92/69/EEC Method B3 Acute Toxicity (dermal).

GLP compliance:

yes

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age/weight at study initiation: at the start of the study, animals were approximately eight weeks of age; males weighed 257 to 310 g, and the females 221 to 237 g.
One group of 5 males and 5 females; no control animals

Type of coverage:

semiocclusive

Vehicle:

arachis oil

Details on dermal exposure:

area covered: approximately 10% of body surface
postexposure period: 14 days

Duration of exposure:

24h

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

there were no deaths

Clinical signs:

other: There were no clinical signs of systemic toxicity. Very slight to well-defined erythema was noted at all treated skin sites one day after dosing with very slight erythema at nine treatment sites to days after dosing. Crust formation was noted at the treat

Gross pathology:

no abnormalities were noted at necropsy

Other findings:

the acute dermal LD50 of the test material, in the male and female rat was found to be greater than 2000 mg/kg bw.
No deficiencies

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test material corresponds to the composition of “coated copper flakes” .
The acute dermal LD50 of the test material, in the male and female rat was found to be greater than 2000 mg/kg bw. In this study, coated copper flakes does not meet the criteria for classification for acute dermal toxicity according to Annex VI of Commission Directive 2001/59/EC

Executive summary:

The test material identity was not provided in details. Considering the information from the reports on the same material, the tested material falls in the composition category of "coated copper flakes" (see– section 1.2), consistent with a biocidal product use (PBD notification was the reason for doing the test).

The acute dermal LD50 of the test material, in the male and female rat was found to be greater than 2000 mg/kg bw. In this study, coated copper flakes does not meet the criteria for classification for acute dermal toxicity according to Annex VI of Commission Directive 2001/59/EC

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High quality

Additional information

The following acute oral data were obtained

·        The acute oral effects - LD_{50 -}observed for coated copper flakes are between 300 and 500 mg/kg.

·        The acute oral lethal effects - LD_{50 -}observed for CuO are >2500 mg/kg.

·        The acute oral effects - LD_{50 -}observed for copper sulphate are 481 mg/kg.

These data are used for the classification of coated copper flakes and for read-across to the classification of copper powders.

Comparison with criteria :Consideration of available acute oral toxicity data against EU classification criteria leads to the conclusion that copper coated flakes do require classification as “harmful” for acute lethal effects (i.e. LD50 <2000 mg/kg and >200 mg/kg BW). 

Considering the lower solubility and bioaccessibility of copper powders compared to copper oxides and copper flakes ( toxicokinetic section of the CSR), the data are read-across to copper powders and copper powders do not require classification for acute lethal effects.

The following acute inhalation data were obtained                                          

 

Acute inhalation studies:

Key study performed according to OECD 436; Reference: Leuschner (2011) (RL1)

The acute inhalation LC₅₀in the rat performed with coated copper flakes was: LC₅₀(4 h) = > 5.11 mg/l (males and females combined)

 

Additional study according to OECD 403; Reference: Wesson (2001)

The acute inhalation LC₅₀in the rat performed with coated copper flakes was:

LC₅₀(4 h) = 1.03 (0.692 - 1.55) mg/l (males and females combined)

LC₅₀(4 h) = 0.733 (0.609 - 0.838) mg/l (males only)

LC₅₀(4 h) = 1.67 (1.41 1.99) mg/l (females only)

For detailed justification - see CSR and below.

RAC 2014 opinion on acute inhalation toxicity for Coated copper flakes

For the inhalation route,the available LC50 values indicate either AcuteTox.3 (based on the2001 Wesson study) or no classification (based on the 2011 Leuschner study).In the Wesson (2001) study,coated copper flakes (fatty acid stabiliser component not given) with a particle size MMAD of around 5µm (4.49-5.86µm,geometric mean standard deviation (GSD) 2.73-3.25) was tested.This is above what is currently required for aerosols in acute inhalation toxicity testing (MMAD1-4µm,GSD1.5-3).For the Leuschner (2011) study (type of aliphatic acid not specified) the MMAD (3.477µm) and GSD (2.61-2.77) were within theses pecifications.According to the industry comments provided during public consultation, the test concentrations in the Wesson (2001) study were not stable: all exceeded the required ±15 or ±25% of the mean achieved concentration at various time points during the exposure period, and were also high (15-70% above the mean value) at the beginning.Variation in the Leuschner study was considerably less: 1.24 ±0.03mg/L and 5.11 ±0.02mg/L. RAC however considers it questionable whether these factors can explain the differences found in the results.The particle size in theWesson(2001) study may have been a little bit higher than recommended,but not so high that most of the material deposited in the respiratory tract would be translocated to the gastrointestinal tract (indeed, the inhalable fraction was still 36.3-45.4%). Hence,it is not so likely that the acute toxicity was determined by that of the oral route, for which classification was already proposed by the dossier submitter. The mean achieved test concentrations in the Wesson (2001) study were only 20-40% of the nominal concentrations and may have been variable, but they never exceeded the dose range that was tested in the Leuschner(2011)study,where these concentrations did not result in mortality. Industry further suggested that, given the production technology at the time of the Wesson (2001) study,zinc stearate may have been the additive in the copper flakes tested.As zinc distearate (EC no 209-151-9) is neither harmonized nor self-classified for acute toxicity via inhalation by any notifiert o the C&l Inventory, this also does not seem to provide an explanation for the differences observed.

Without sufficient reasons to discard the results of the Wessonstudy, RAC retained the Wesson 2001 study.

In the RAC Opinion from 2014, RAC members agreed that CuO should not be classified for acute toxicity via inhalation route

Conclusion: The results from the acute inhalation toxicity studies (Wesson,2001) has been carried forward to assess the hazards of coated copper flakes. The acute inhalation toxicity used for classification purposes is therefore 0.7 mg/L

 

Comparison with criteria

Coated copper flakes: The inhalation LC50 for the reliable study with coated copper flakes (RL) is below the classification cut-off value of 5 mg/L under directive 67/548/EEC and regulation (EC) 1272/2008. Coated copper flakes therefore require classification for acute lethal effects

Considering the lower solubility and bioaccessibility and the higher particle size of copper powders compared to coated copper flakes, the data are read-across to copper powders and copper powders do not require classification for acute lethal effects.

The following acute dermal were obtained

The acute lethal effects - LD_{50 -}observed for coated copper flakes, for CuO and for Cu sulphate are >2000 mg/kg.

The acute studies on coated copper flakes and copper compounds are used for the classification of coated copper flakes and for read-across to the classification of copper powders.

Comparison with criteria :Consideration of available acute dermal toxicity data against EU classification criteria leads to the conclusion that copper coated flakes do not require classification for acute lethal effects (i. e. LD₅₀>2000 mg/kg). 

Considering the lower solubility and bioaccessibility of copper powders compared to copper oxides and copper flakes, the data are read-across to copper powders and copper powders do not require classification for acute lethal effects.

Justification for selection of acute toxicity – oral endpoint
For coated copper flakes, several studies are used in a WoE. Sanders (2001 a) reported an LD50 for coated copper flakes (Reliability Q2). The study was not available for the VRA discussions. The information is highly relevant and the study was retained as critical. Additional high quality (Q1) Cu2+ LD50 values for copper sulphate (soluble) and CuO (sparingly soluble), already evaluated by the competent authorities on existing substances and biocides (and reported in the VRA), are also considered. All information is used in a weight of evidence approach for the classification of coated copper flakes . For the hazard profile of copper powder, information on bioaccessibility (CSR Chapter 5.1) are combined with the hazard profile of the coated copper flakes and copper compounds (see CSR Chapter 5.1). No hazard are expected for copper powders and massives

Justification for selection of acute toxicity – inhalation endpoint
For the hazard profile of coated copper flakes, two studies are available. The lower quality study demonstrating highest toxicity (Wesson, 2001) was retained by RAC. The lowest tested concentration in Wesson 2001 (590 mg Cu/m3) is retained as LOEC. At this dose 1/5 animals died during the exposure period. Surviving animals demonstrated decreased or increased respiratory rate and wet fur were noted in all animals and there was a single instance of laboured respiration  All surviving animals were asymptomatic from Day 8 of the recovery period. No hazard are expected for copper powders (>10µm)) and massive (>1mm.) See CSR Chapter 5.2.3

Justification for selection of acute toxicity – dermal endpoint
Several studies are used in WoE. The studies were already evaluated by competent authorities on existing substances and biocides. The Q2 study on coated copper flakes is a critical study. The Q1 studies on CuSO4 and CuO are used in weight of evidence approach to conclude on " no adverse effects of Cu2+-ions"

Justification for classification or non-classification

ACUTE LETHAL CLASSIFICATION

Acute oral classification

- Based on the available acute oral toxicity data, coated copper coated flakes should be classified as ‘harmful’ (Xn) (i.e. LD50 <2000 mg/kg and >200 mg/kg BW and calculated to be between 300 and 500 mg/kg body weight) and assigned the DSD risk phrase R22 (harmful if swallowed) and the GHS risk phrase H302 (harmful if swallowed).

- No acute toxicity data are available for copper powders. Useful to mention that copper powders and coated copper flakes are produced via very distinct processes. The coating of the particles is needed to obtain very fine flakes with high surface area. The surface area of coated copper flakes (8-10 µm) was measured as 2.9 m2/g (Liipo et al., 2010). The surface area of a typical powder was measured as 0.024 m2/g.  A much higher reactivity, solubility of the coated copper flakes compared to copper powders can therefore be anticipated.

The classification of copper powders therefore includes comparative bioavailability and read across from toxicity data obtained for copper flakes and copper compounds.

With oral administration of soluble and insoluble copper substances, copper occurs in the GIT, at least in part, in the ionic form and is therefore available for absorption and/or to cause local effects. Good quality acute oral toxicity data exist for CuO, Cu Sulphate and copper coated flakes. The date from copper (II) oxide, indicates no requirement for classification, while the data for (CuSO4) and coated copper flakes indicate the requirement for classification as ‘harmful’ (Xn; R22). The solubility of cupric-ions seems to be an important factor for acute oral toxicity. Information on solubility in in-vitro systems was proposed in the VRAR as useful for classification.

Such information, has become available (see toxicokinetics) and demonstrated large differences in relative bio-accessibility for the different copper containing materials: relative copper bio-accessibility in gastric fluids of 0.1 and 1% were noted for respectively copper massive and copper powders,  compared to 42-71% for the coated copper flakes and 68-84% for CuO and 100% for copper sulphate.

Useful to mention that the coated copper flakes used for the toxicity tests are not well defined – from the information obtained from the Q3 inhalation report on the same substance a particle size of 5 µm is assumed, compared to a particle size of 8.5 µm, used for the comparative biosolubility tests.  It is therefore reasonable to assume that the bio-solubility of the coated copper flakes used for the acute oral toxicity tests is > 42-71%. This may explain why the coated copper flakes did show toxicity at 2000 mg/kg dry weight while CuO did not.

Considering the much lower biosolubility in gastric fluids of copper powders and massives compared (0.1-1%) to copper flakes, no classification for copper powders and copper massives is proposed.

Further evidence for the absence of concerns related to “acute oral toxicity” of copper in powder and massive forms can be obtained from the toxicity data, expressed as “bio-soluble” copper for respectively copper flakes and Cu sulphate. The bio-soluble effects levels are calculated in as the LD 50 (mg substance/kg Bwt) x % Cu x % biosoluble. 

Table Acute toxicity of copper compounds, expressed as external doses of substance and calculated as internal dose, using the biosolubility data

 

Source Material tested	Administered LD50  (mg substance /kg Bwt)	Cu Bio-solubility (%)	LD50 as biosoluble Cu (mg Cu/kg Bwt)
Cu flakes; 98% Cu	300-500 (5µm)	42-71 (8.5 µm)	231 (121-341) (5µm)
CuSO4; 25.45% Cu	481	100	123

A linear relationship was observed between the surface area and the copper bio-solubility in gastric fluids. Linear extrapolation allows to demonstrate that a relative Cu bio-solubility of <16% is needed to be outside of the criteria for an oral classification entry. The relative bio-solubility’s of copper powder and of copper massive materials are respectively 1% and 0.1%, further confirming that for copper powders and massives, there is no need for an acute oral classification entry.

As a further weight of evidence, relevant to the read-across approach, the measured LD₅₀values of the various source materials (coated flakes, CuS0_4.5H₂O and CuCl) were expressed as mg bio-accessible Cu/kg bw and combined with the % bio-accessible Cu released from the various copper bearing materials to predict the LD₅₀values (see also Table below and in CSR).

The Table below shows comparable bioavailable/bioaccessible LD50 values for the 3 substances with bound LD50 data (122 to 227 mg bio-available mg Cu/kg bw). The predicted LD50 values for these materials (copper coated flakes, CuSO_4.5H₂0 and CuCl) correspond to the measured hazard profile of these materials (LD₅₀< 2,000 mg/kg and > 200 mg/kg bw). Correct predictions are also observed for Cu₂S (i.e. LD₅₀> 2,000 mg/kg). For CuO, the predicted LD50 values are below the observed LD50 and therefore, predictions are conservative.

Therefore, following the read-across approach, the in vivo toxicity of coated copper flakes and copper compounds were combined with the relative bio-accessibility of copper powders and massive in gastric fluids to derive the acute oral classification entry for copper powders/massive.  From the assessment (Table43) it was concluded that copper powder (typical powder and worst case 10µm powder) and therefore also copper massive follow the same hazard profile as CuO and Cu₂S (LD₅₀> 2,000 mg/kg) : they do not merit acute oral classification.

Table Predictions of the LD50 values for the various copper materials

Cu Material	Copper content	Bio-accessible/ bio-availability Cu	LD50as bio-accessible Cu	Measured LD50	Predicted LD50**
	%	%	(mg Cu/kg bw)	LD50 (mg substance/kg bw)	LD50 (mg substance/kg bw)
Coated flakes (2.9m2/g)	99.7	57	227	400 (mid value of 300 -500 mg/kg)	215-401
CuSO4.5H20	25.4	25	122	481	480-894
CuCl	63.78	51	173	336	232-442
Copper powder (0.024m2/g)	100	1.1			11091-20636
10 µm copper powder (0.067m2/g)	100	2.8			4357-8107

 *Predicted as “Measured LD50” x “% bioaccessible Cu”     

** predicted as “range LD50 as bioaccessible Cu”/ “range in % bio-accessible/bio-available Cu

From this read-across assessment it can thus be concluded that copper in massive and powder forms do not meet the criteria for acute oral classification. 

Acute inhalation classification:

A total of two inhalation studies are available on coated copper flakes:

(i) Leuschner, J. (2011): The inhalation LC50 for coated copper flakes (well defined test item composition) is above the classification cut-off value of 5 mg/L (i.e., ≥ 5.11 mg/L) under directive 67/548/EEC and regulation (EC) 1272/2008. No C&L is required. The study is rated with RL1.

 (ii) Wesson, CM. (2001): The inhalation study performed with coated copper flakes results in calculated LC50 values of 1.03 mg/L for males & females combined, 0.733 mg/L for males and 1.67 mg/L for females. The values for females and males & females in combination are within the range (1-5 mg/L/4h) for classification as Xn (Harmful); R20 (Harmful by inhalation) under Directive 67/548/EEC and as Acute Inhalation Tox.4 (H332: Harmful if inhaled) under Regulation (EC) 1272/2008. The study is rated with RL3.

Based on the RAC 2014 opinion, the study of Wesson (2001) iscarried forward to assess classification and risk characterisation. The inhalation LC₅₀for coated copper flakes is < 1 mg/L and leads, under directive 67/548/EEC and regulation (EC) 1272/2008 to a classification as Acute Tox 3 toxic if inhaled. During exposure, decreased respiratory rate, laboured respiration were noted and mortality occurred within 24 hours. Effects were primarily associated to abnormal findings in the lungs (enlarged, dark patches, pale, pale patches, dark foci, fluid filled, discolouration, haemorrhagic, abnormally dark).

Acute inhalation toxicity was not tested for copper powders. Acute inhalation toxicity is related to local respiratory effects and will be determined to a large extent by particle size and solubility. Other physical/chemical properties may also be involved. Solubility of copper powders was demonstrated to be very low compared to the solubility of the copper flakes (1% for copper powders versus 42-71% for coated copper flakes- see section comparative bio-availability). The inhalation toxicity of coated copper flakes demonstrated mortality by local damage at the site of predominant deposition of particles (mortality within 24 hours, clear effect on respiratory tract and abnormal finding in lungs). The particles in the respirable and possibly thoracic particle size range are therefore the primarily responsible for the observed effects. The relative importance of respirable fraction (<4 µm) and thoracic fraction ( <10µm) are therefore critical to the assessment. For classification purposes, it is therefore important to assess the sizes of the copper particles put on the market: 99.6% of the copper used/marketed are massive forms (particle sizes >1mm). The copper powder market (particle size <1mm) is less then 0.4% of the total copper market. Copper powders put on the market have d50 values ranging between 10 µm and 1 mm. Experimental particle size distribution data for copper powders, showed that <5% of the representative copper powder sample tested had a particle size of 10 µm or below (EBRC Consulting, 2005 – unpublished study in the copper RA report). More recent information (Liipo et al, 2010) also demonstrated that <5% of a representative copper powder sample had a particle size of <10 µm. Information from a sample, representing the smallest particle size range sold by a key producer (D50=18 µm) demonstrated that <25% of this very fine powder sample had a particle size of <10µm. Consideration of the available information on particle size distribution of copper and copper powder therefore leads to the conclusion that copper in its powder and massive forms do not meet the requirements for classification for acute inhalation effects.   

As another weight of evidence towards “no classification of copper powders”, it seems useful to also consider the RAC opinion (2014) for CuO: no classificatuion based on the lower solubility of CuO compared to classified copper compounds.

Acute dermal classification:

Consideration of available acute dermal toxicity data against EU classification criteria leads to the conclusion that copper coated flakes donotrequire classification for acute lethal effects (i. e. LD₅₀>2000 mg/kg). Considering the lower solubility and bioaccessibility of copper powders compared to copper oxides and copper flakes, the data are read-across to copper powders and copper powders donotrequire classification for acute lethal effects.

CLASSIFICATION AS SPECIFIC TARGET ORGAN TOXICITY - SINGLE DOSE

Acute toxicity, 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 organ-specifc health effects were observed immediately or delayed after exposure at the guidance value, oral for a Category 1 classification of 300 mg/kg bw and at the guidance value, oral for a Category 2 classification of 2000 mg/kg bw in addition to these effects which were responsible for the death of the animals. No classification required.

Acute toxicity, 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, in addition, to the effects which were responsible for the death of the animals, no reversible or irreversible adverse organ-specifc health effects were observed immediately or delayed after exposure at the guidance value, inhalation (dust/mist/fume) for a Category 1 classification (C ≤ 1 mg/L/4h) and at the guidance value, inhalation for a Category 2 (5.0 ≥ C > 1.0 mg/L/4h). No classification is required.  

  

Acute toxicity, dermal:            

The classification criteria according to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, dermal 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, dermal for a Category 1 classification (C ≤ 1000 mg/kg bw) and at the guidance value, dermal for a Category 2 classification (2000 mg/kg bw ≥ C > 1000 mg/kg bw). No classification required

Comparison with criteria

There was no clear evidence of any specific toxic effects on a target organ or tissue. Clinical signs of toxicity were observed after single exposures to copper but were transient in nature and are considered to be unspecific signs of general acute toxicity

No classification as STOT-SE under regulation (EC) 1272/2008 is considered necessary