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Registration Dossier
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EC number: 825-116-6 | CAS number: 24704-41-4
Endpoint summary
Administrative data
Description of key information
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Justification for type of information:
- The study is well-documented by the publication and thus acceptable for assessment.
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- Deviations:
- yes
- Remarks:
- No information about: stability of the test item, individual weights, number of died or killed animals. Observation period was only 10 days. Necropsy information only of the animals which were treated orally with cobalt(II) fluoride and cobalt(II) oxide.
- GLP compliance:
- not specified
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Route of administration:
- oral: gavage
- Vehicle:
- water
- Doses:
- Cobalt(II) fluoride (CoF2): 70, 112, 180, 290, 460 mg/kg body weight
Cobalt(II) oxide (CoO): 200, 300, 450, 675, 1010 mg/kg body weight
Cobalt(II) phosphate octahydrate (Co3(PO4)2*8H2O): 300, 450, 675, 1000, 1500 mg/kg body weight
Cobalt(II) bromide (CoBr2): 200, 300, 450, 675, 1010 mg/kg body weight
Cobalt(II) chloride hexahydrate (CoCl2*6H2O): 500, 600, 720, 864, 1137 mg/kg body weight
Cobalt(II) sulphate heptahydrate (CoSO4*7H2O): 450, 675, 1000, 1500, 2250 mg/kg body weight
Cobalt(II) nitrate hexahydrate (Co(NO3)2*6H2O): 450, 675, 1000, 1500, 2250 mg/kg body weight
Cobalt(II) acetate tetrahydrate (Co(CH3COO)2*4H2O): 250, 375, 560, 840, 1260 mg/kg body weight - No. of animals per sex per dose:
- 5 males / 5 females
- Control animals:
- not specified
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 150 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoF2
- 95% CL:
- >= 115 - <= 195
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 202 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoO
- 95% CL:
- >= 136 - <= 300
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 539 mg/kg bw
- Based on:
- test mat.
- Remarks:
- Co3(PO4)2*8H2O
- 95% CL:
- >= 425 - <= 683
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 406 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoBr2
- 95% CL:
- >= 330 - <= 500
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 766 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoCl2*6H2O
- 95% CL:
- >= 677 - <= 867
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 768 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoSO4*7H2O
- 95% CL:
- >= 594 - <= 995
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 691 mg/kg bw
- Based on:
- test mat.
- Remarks:
- Co(NO3)2*6H2O
- 95% CL:
- >= 526 - <= 907
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 708 mg/kg bw
- Based on:
- test mat.
- Remarks:
- Co(CH3CO2)2*4H2O
- 95% CL:
- >= 569 - <= 880
- Clinical signs:
- The highest dose caused sedation and diarrhoea. Rats given cobalt(II) sulphate or chloride also showed tremors and convulsions prior to death. Respiratory disturbances were apparent in rats given acetate. Animals in the cobalt(II) fluoride group did not show any of these effects. In all animals a decrease in body temperature was recorded. The temperature reductions were time- and dose-related.
- Body weight:
- No data
- Gross pathology:
- Rats given cobalt(II) fluoride revealed severely haemorrhagic mucosal tissue and in addition the stomach was filled with a colourless fluid.
- Other findings:
- Histopathological examination of animals that died in the groups treated with cobalt(ll) fluoride:
liver: glycogen depletion; frequently diffuse vacuolization; in some animals hyperaemia; cytoplasmic changes
kidneys: in some animals hyperaemia; glomeruli were very rich in cells and basal membranes were thickened; cells of the proximal tubules were swollen and exhibited slight vacuolization and degeneration.
other organs: Three of the animals given the 290-mg/kg dose showed myocardial changes consisting of proliferative and oedematous interstitial tissue and swollen muscle fibres with focal degeneration.
Histopathological examination of animals that died in the groups treated with cobalt(ll) oxide:
similar to the examination of animals that died in the groups treated with cobalt(II) fluoride
In addition to hyperaemia, some haemorrhage was observed, especially in the heart
heart: swollen and eosinophilic muscle fibres were observed.
In some animal's vacuolization, degeneration and necrosis of the myocardium was associated with disappearance of the cross-striations. In these areas mitotic activity was also apparent, probably in developing fibroblasts. - Conclusions:
- Eight cobalt compounds were administered to rats by gastric intubation, and the following LD50 values were determined: cobalt(II) fluoride (CoF2) 150 mg/kg bw, cobalt(II) oxide (CoO) 202 mg/kg bw, cobalt(II) phosphate octahydrate (Co3(PO4)2*8H2O) 387 mg/kg bw, cobalt(II) bromide (CoBr2) 406 mg/kg bw, cobalt(II) chloride hexahydrate (CoCl2*6H2O) 418 mg/kg bw, cobalt(II) sulphate heptahydrate (CoSO4*7H2O) 424 mg/kg bw, Cobalt(II) nitrate hexahydrate (Co(NO3)2*6H2O) 434 mg/kg bw and cobalt(II) acetate tetrahydrate (Co(CH3COO)2*4H2O) 503 mg/kg bw.
- Executive summary:
The oral LD50 values calculated for the cobalt percentage in the cobalt(II) compounds were: cobalt(II) fluoride 91 mg/kg bw, cobalt(II) oxide 159 mg/kg bw, cobalt(II) phosphate 187 mg/kg bw, cobalt(II) bromide 109 mg/kg bw, cobalt(II) chloride 190 mg/kg bw, cobalt(II) sulphate 161 mg/kg bw, cobalt(II) nitrate 140 mg/kg bw and cobalt(II) acetate 167 mg/kg bw.
- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Justification for type of information:
- The study is well-documented by the publication and thus acceptable for assessment.
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 401 (Acute Oral Toxicity)
- GLP compliance:
- not specified
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male/female
- Route of administration:
- oral: gavage
- Vehicle:
- water
- Doses:
- Cobalt(II) chloride hexahydrate (CoCl2*6H2O): 350, 392, 450, 518, 595, 684, 787 mg/kg body weight
Cobalt(II) sulphate heptahydrate (CoSO4*7H2O): 1000, 1110, 1232, 1368, 1520, 1685 mg/kg body weight
Cobalt(II) nitrate hexahydrate (Co(NO3)2*6H2O): 726, 802, 886, 979, 1061, 1196 mg/kg body weight
Cobalt(II) acetate tetrahydrate (Co(CH3COO)2*4H2O): 600, 645, 693, 745, 801, 861, 926, 995 mg/kg body weight - No. of animals per sex per dose:
- 8 or 10 animals (It was not clearly stated in the publication how many males and females were used per dose and if the genders were equally distributed.)
- Control animals:
- yes
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 537 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoCl2*6H2O
- 95% CL:
- >= 479 - <= 601
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 1 330 mg/kg bw
- Based on:
- test mat.
- Remarks:
- CoSO4*7H2O
- 95% CL:
- >= 1 220 - <= 1 450
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 978 mg/kg bw
- Based on:
- test mat.
- Remarks:
- Co(NO3)2*6H2O
- 95% CL:
- >= 897 - <= 1 066
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 819 mg/kg bw
- Based on:
- test mat.
- Remarks:
- Co(CH3CO2)2*4H2O
- 95% CL:
- >= 751 - <= 891
- Mortality:
- The majority of deaths occurred during the first 48 hours.
The following percentage of animals died at the different dose levels:
CoCl2*6H2O
350 mg/kg: 0 %
392 mg/kg: 10 %
450 mg/kg: 37.5 %
518 mg/kg: 50 %
595 mg/kg: 75 %
684 mg/kg: 75 %
787 mg/kg: 100 %
CoSO4*7H2O:
1000 mg/kg: 0 %
1110 mg/kg: 10 %
1232 mg/kg: 30 %
1368 mg/kg: 50 %
1520 mg/kg: 80 %
1685 mg/kg: 100 %
Co(NO3)2*6H2O:
726 mg/kg: 0 %
802 mg/kg: 12.5 %
886 mg/kg: 12.5 %
979 mg/kg: 37.5 %
1061 mg/kg: 87.5 %
1196 mg/kg: 100 %
Co(CH3COO)2*4H2O:
600 mg/kg: 0 %
645 mg/kg: 20 %
693 mg/kg: 20 %
745 mg/kg: 30 %
801 mg/kg: 50 %
861 mg/kg: 50 %
926 mg/kg: 70 %
995 mg/kg: 100 % - Clinical signs:
- The physical and clinical signs appearing after the intoxication disappeared for the most part after the first 72 hours.
- Body weight:
- No data
- Other findings:
- A noteworthy increase was observed in the hemoglobin and hematocrit as well as in the plasma proteins. There was significant hyperglycemia and significant changes in the lipid parameters such as triglycerides and cholesterol. The duration and degree of the change depended on the dose.
- Conclusions:
- Four cobalt compounds were administered to rats and the following LD50 values were determined: cobalt(II) chloride hexahydrate (CoCl2*6H2O) 537 mg/kg bw, cobalt(II) sulphate heptahydrate (CoSO4*7H2O) 1330 mg/kg bw, Cobalt(II) nitrate hexahydrate (Co(NO3)2*6H2O) 978 mg/kg bw and cobalt(II) acetate tetrahydrate (Co(CH3COO)2*4H2O) 819 mg/kg bw.
- Executive summary:
The oral LD50 values calculated for the cobalt percentage in the cobalt(II) compounds were: cobalt(II) chloride 133 mg/kg bw, cobalt(II) sulphate 279 mg/kg bw, cobalt(II) nitrate 198 mg/kg bw and cobalt(II) acetate 194 mg/kg bw.
- Endpoint:
- acute toxicity: oral
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Justification for type of information:
- The complex EDTA-CoH2 consist of the organic moiety EDTA, the central atom Co2+ and the hydrogen ions. As the latter are known to be non-toxic only the EDTA-Co complex must be regarded as toxic. For both, free EDTA and Co2+ compounds well-documented studies are available, which shows their toxicity. In general, the complex with the chelated Co2+ ion can be considered as less toxic than the free Co2+ ion due to retarded release. Based on that and that the complex EDTA-Co has an average stability, a worst-case assessment where the EDTA-CoH2 complex dissociates in its components can be done and so a read-across is possible to free EDTA and Co2+ salts.
- Reason / purpose for cross-reference:
- read-across source
- Reason / purpose for cross-reference:
- read-across source
- Specific details on test material used for the study:
- Different cobalt(II) salts were used.
- Key result
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 729 mg/kg bw
- Based on:
- test mat.
- Interpretation of results:
- Category 4 based on GHS criteria
- Conclusions:
- The oral LD50 value of 648.52 mg/kg bw could be calculated for the test substance, which leads to the category 4 classification according to the regulation 1272/2008 (CLP-Regulation).
- Endpoint:
- acute toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Comparable to OECD 401 guideline study with acceptable restrictions [Body weight was only determined at the beginning of the study (OECD: weekly); Observation period: 7 days (OECD:14 days)]
- Principles of method if other than guideline:
- BASF-TEST: In principle, the methods described in the OECD Guideline 401 were used. Young adult laboratory rats were purchased from breeder. Usually the source and strain of animals were not documented. Several groups of 5 rats per sex and dose were treated simultaneously by gavage with preparations of the test substance in suitable vehicle. The concentrations of these preparations were used to achieve comparable volumes per kg body weight. Group-wise documentation of clinical signs was performed over the 7 day study period. Body weight was determined before the start of the study only, as it was needed for determination of dose
- GLP compliance:
- no
- Test type:
- standard acute method
- Species:
- rat
- Strain:
- not specified
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Mean body weight at study initiation:
259 g males/ 211 g females - Route of administration:
- oral: gavage
- Vehicle:
- CMC (carboxymethyl cellulose)
- Details on oral exposure:
- DOSAGE PREPARATION:
- Stock solutions prepared: 30 %
- Dose volume applied: 2500 mg/kg bw dose group:
8.33 mL/kg bw
3200 mg/kg bw dose group: 10.66 mL/kg bw
4000 mg/kg bw dose group: 13.33 mL/kg bw
5000 mg/kg bw dose group: 16.66 mL/kg bw
6400 mg/kg bw dose group: 21.4 mL/kg bw - Doses:
- 2500; 3200; 4000; 5000; 6400 mg/kg bw
- No. of animals per sex per dose:
- 5
- Control animals:
- no
- Details on study design:
- - Duration of observation period following administration: 7 days;
- The animals were observed for mortality and clinical signs of toxicity;
- Frequency of observations: Several times on the application day, thereafter once each working day;
- Body weights were only recorded at the beginning of the study;
- Necropsy of survivors and animals which died performed: yes - Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 2 800 mg/kg bw
- Mortality:
- - One female died in the 2500 mg/kg bw dose group; 9/10 animals died in the 3200 mg/kg bw dose group and all animals of the higher dose groups (see "Any other information on results incl. tables").
- Clinical signs:
- - 2500, 3200 and 4000 mg/kg bw: directly after application: accelerated respiration, squatting posture, twitching, ataxia, red eyes, some animals showed light secretion, reluctance to move; the next day: squatting posture, contaminated fur, intermittened respiration, reluctance to move; fully reversible within 6 days
- 5000 and 6400 mg/kg bw: directly after application: accelerated respiration, squatting posture, twitching, ataxia, red eyes, some animals showed light secretion, reluctance to move; later: prone position - Body weight:
- Body weights were not recorded during and at the end of the observation period
- Gross pathology:
- Animals which died:
- heart: acute dilatation, venous hyperemia
- liver: congestion
- gut: diarrhea like content
- stomach: dilatation
- kidneys: degeneration
Animals which were sacrificed:
- nothing abnormal detected - Interpretation of results:
- GHS criteria not met
- Endpoint:
- acute toxicity: oral
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Comparable to OECD 401 guideline study with acceptable restrictions [Body weight was only determined at the beginning of the study (OECD: weekly); Observation period: 7 days (OECD:14 days)]
- Justification for type of information:
- The complex EDTA-CoH2 consist of the organic moiety EDTA, the central atom Co2+ and the hydrogen ions. As the latter are known to be non-toxic only the EDTA-Co complex must be regarded as toxic. For both, free EDTA and Co2+ compounds well-documented studies are available, which shows their toxicity. In general, the complex with the chelated Co2+ ion can be considered as less toxic than the free Co2+ ion due to retarded release. Based on that and that the complex EDTA-Co has an average stability, a worst-case assessment where the EDTA-CoH2 complex dissociates in its components can be done and so a read-across is possible to free EDTA and Co2+ salts.
- Reason / purpose for cross-reference:
- read-across source
- Principles of method if other than guideline:
- BASF-TEST: In principle, the methods described in the OECD Guideline 401 were used. Young adult laboratory rats were purchased from breeder. Usually the source and strain of animals were not documented. Several groups of 5 rats per sex and dose were treated simultaneously by gavage with preparations of the test substance in suitable vehicle. The concentrations of these preparations were used to achieve comparable volumes per kg body weight. Group-wise documentation of clinical signs was performed over the 7 day study period. Body weight was determined before the start of the study only, as it was needed for determination of dose
- GLP compliance:
- no
- Test type:
- standard acute method
- Species:
- rat
- Strain:
- not specified
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Mean body weight at study initiation:
259 g males/ 211 g females - Route of administration:
- oral: gavage
- Vehicle:
- CMC (carboxymethyl cellulose)
- Details on oral exposure:
- DOSAGE PREPARATION:
- Stock solutions prepared: 30 %
- Dose volume applied: 2500 mg/kg bw dose group:
8.33 mL/kg bw
3200 mg/kg bw dose group: 10.66 mL/kg bw
4000 mg/kg bw dose group: 13.33 mL/kg bw
5000 mg/kg bw dose group: 16.66 mL/kg bw
6400 mg/kg bw dose group: 21.4 mL/kg bw - Doses:
- 2500; 3200; 4000; 5000; 6400 mg/kg bw
- No. of animals per sex per dose:
- 5
- Control animals:
- no
- Details on study design:
- - Duration of observation period following administration: 7 days;
- The animals were observed for mortality and clinical signs of toxicity;
- Frequency of observations: Several times on the application day, thereafter once each working day;
- Body weights were only recorded at the beginning of the study;
- Necropsy of survivors and animals which died performed: yes - Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- 2 800 mg/kg bw
- Mortality:
- - One female died in the 2500 mg/kg bw dose group; 9/10 animals died in the 3200 mg/kg bw dose group and all animals of the higher dose groups (see "Any other information on results incl. tables").
- Clinical signs:
- - 2500, 3200 and 4000 mg/kg bw: directly after application: accelerated respiration, squatting posture, twitching, ataxia, red eyes, some animals showed light secretion, reluctance to move; the next day: squatting posture, contaminated fur, intermittened respiration, reluctance to move; fully reversible within 6 days
- 5000 and 6400 mg/kg bw: directly after application: accelerated respiration, squatting posture, twitching, ataxia, red eyes, some animals showed light secretion, reluctance to move; later: prone position - Body weight:
- Body weights were not recorded during and at the end of the observation period
- Gross pathology:
- Animals which died:
- heart: acute dilatation, venous hyperemia
- liver: congestion
- gut: diarrhea like content
- stomach: dilatation
- kidneys: degeneration
Animals which were sacrificed:
- nothing abnormal detected - Interpretation of results:
- GHS criteria not met
- Conclusions:
- The LD50 of the test substance EDTA-Na2 is 2800 mg/kg bw which leads to no classification as acute toxicity oral in accordance with regulation (EC) No 1272/2008 (CLP-regulation). This confirms that only the toxicity of cobalt(II) has to be taken into account for the toxicity of EDTA-CoH2.
Referenceopen allclose all
The oral LD50 values calculated for the anhydrous cobalt(lI) compounds were: cobalt(II) fluoride 150 mg/kg bw, cobalt(II) oxide 202 mg/kg bw, cobalt(II) phosphate 387 mg/kg bw, cobalt(II) bromide 406 mg/kg bw, cobalt(II) chloride 418 mg/kg bw, cobalt(II) sulphate 424 mg/kg bw, cobalt(II) nitrate 434 mg/kg bw and cobalt(II) acetate 503 mg/kg bw.
The oral LD50 values calculated for the cobalt percentage in the cobalt(II) compounds were: cobalt(II) fluoride 91 mg/kg bw, cobalt(II) oxide 159 mg/kg bw, cobalt(II) phosphate 187 mg/kg bw, cobalt(II) bromide 109 mg/kg bw, cobalt(II) chloride 190 mg/kg bw, cobalt(II) sulphate 161 mg/kg bw, cobalt(II) nitrate 140 mg/kg bw and cobalt(II) acetate 167 mg/kg bw.
The oral LD50 values calculated for the cobalt percentage in the cobalt(II) compounds were: cobalt(II) chloride 133 mg/kg bw, cobalt(II) sulphate 279 mg/kg bw, cobalt(II) nitrate 198 mg/kg bw and cobalt(II) acetate 194 mg/kg bw.
The oral LD50 values calculated for the cobalt percentage in the cobalt(II) compounds of the read-across sources were: cobalt(II) fluoride 91 mg/kg bw, cobalt(II) oxide 159 mg/kg bw, cobalt(II) phosphate 187 mg/kg bw, cobalt(II) bromide 109 mg/kg bw, cobalt(II) chloride 133 and 190 mg/kg bw, cobalt(II) sulphate 161 and 279 mg/kg bw, cobalt(II) nitrate 140 and 198 mg/kg bw and cobalt(II) acetate 167 and 194 mg/kg bw.
For the calculation of the LD50 value of EDTA-CoH2 the lowest toxicity value of 109 mg/kg bw from cobalt(II) bromide was used. Regarding the molecular weight of EDTA-CoH2 an oral LD50 value of 648.52 mg/kg bw could be calculated.
LD50, corrected = 349.16 g/mol / 58.9 g/mol * 109.4 mg/kg bw = 648.52 mg/kg bw
The toxicity value of cobalt(II) fluoride cannot be regarded, as the toxicity also strongly depends on the fluoride ion.
Table 1: Mortalities of rats after oral application
| 2500 mg/kg bw | 3200 mg/kg bw | 4000 mg/kg bw | 5000 mg/kg bw | 6400 mg/kg bw | ||
| 1 h | male | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 |
| female | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 | |
| 24 h | male | 0/5 | 3/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 | |
| 48 h | male | 0/5 | 3/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 | |
| 7 d | male | 0/5 | 4/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 |
Table 1: Mortalities of rats after oral application
| 2500 mg/kg bw | 3200 mg/kg bw | 4000 mg/kg bw | 5000 mg/kg bw | 6400 mg/kg bw | ||
| 1 h | male | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 |
| female | 0/5 | 0/5 | 0/5 | 0/5 | 0/5 | |
| 24 h | male | 0/5 | 3/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 | |
| 48 h | male | 0/5 | 3/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 | |
| 7 d | male | 0/5 | 4/5 | 5/5 | 5/5 | 5/5 |
| female | 1/5 | 5/5 | 5/5 | 5/5 | 5/5 |
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- LD50
- Value:
- 648.52 mg/kg bw
Additional information
Justification for classification or non-classification
The complex EDTA-CoH2 consist of the organic moiety EDTA, the central atom Co2+ and the hydrogen ions. As the latter are known to be non-toxic only the EDTA-Co complex must be regarded as toxic. For both, free EDTA and Co2+ compounds well-documented studies are available, which shows their toxicity. In general, the complex with the chelated Co2+ ion can be considered as less toxic than the free Co2+ ion due to retarded release. Based on that and that the complex EDTA-Co has an average stability (stability constant K=10^18.1; Environ. Sci. Technol. 2000, 34, 1715-1720), a worst-case assessment where the EDTA-CoH2 complex dissociate in its components can be done and so a read-across is possible to free EDTA and Co2+ salts.
The LD50 of the test substance EDTA-Na2 is 2800 mg/kg bw which leads to no classification as acute toxicity oral in accordance with regulation (EC) No 1272/2008 (CLP-regulation). Therefore, special attention must be paid to the central atom cobalt of the EDTA complex.
For different cobalt(II) compounds oral LD50 values were determined in well documented studies which meets generally accepted scientific principles and are acceptable for the assessment (Spejers et al. Fd Chem. Toxic, 1982, 20, 311-314 and Llobet et al. Revista espanola de fisiologia, 1983, 39/3, 291-298). On this basis, oral LD50 values could be calculated for the cobalt percentage in the cobalt(II) compounds: cobalt(II) fluoride 91 mg/kg bw, cobalt(II) oxide 159 mg/kg bw, cobalt(II) phosphate 187 mg/kg bw, cobalt(II) bromide 109 mg/kg bw, cobalt(II) chloride 133 and 190 mg/kg bw, cobalt(II) sulphate 161 and 279 mg/kg bw, cobalt(II) nitrate 140 and 198 mg/kg bw and cobalt(II) acetate 167 and 194 mg/kg bw.
For the calculation of the LD50 value of EDTA-CoH2 the lowest toxicity value of 109 mg/kg bw from cobalt(II) bromide was used. Regarding the molecular weight of EDTA-CoH2 an oral LD50 value of 648.52 mg/kg bw could be calculated.
LD50, corrected = 349.16 g/mol / 58.9 g/mol * 109.4 mg/kg bw = 648.52 mg/kg bw
This value leads to the category 4 classification of EDTA-CoH2 according to the regulation 1272/2008 (CLP-Regulation).
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