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Administrative data

Description of key information

- Repeated dose toxicity, oral:
• FeCl3: no classification, NOAEL = 277 mg/kg bw/d, LOAEL = 554 mg/kg bw/d, 1 study (probably comparable to OECD TG 408)
• Fe2(SO4)3: no classification, no studies available, accordingly read across is used from FeCl3: NOAEL = 277 mg/kg bw/d * (399.88 g/mol/2 * 162.21 g/mol) = 341.4 mg/kg bw/d, LOAEL = 683 mg/kg bw/d
• FeCl2: no classification (as treatment period was at least 42 d and dosed 7 d/week), NOAEL = 125 mg/kg bw, LOAEL: 250 mg/kg bw, 1 study (compliant to OECD TG 422 and GLP
• FeSO4: no classification (effects at 163.9 mg/kg bw/d not sufficient for classification), NOAEL = 54.6 mg/kg bw, LOAEL = 163.9 mg/kg bw/d for anhydrous FeSO4, 1 study (compliant to OECD TG 422 and GLP)
• FeClSO4: no classification, no studies available, accordingly read across is used from FeCl3: NOAEL = 277 mg/kg bw/d * (187.36 g/mol/62.21 g/mol) = 319.9 mg/kg bw/d, LOAEL = 639.9 mg/kg bw/d
- Repeated dose toxicity, dermal: no studies available
- Repeated dose toxicity, inhalation:
• FeCl3: one reliable but not sufficient conclusive for classification study in rabbits reported a LOAEL of 1.4 mg Fe/m³, when exposed to FeCl3 aerosol

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
125 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
The available rat test data for FeCl3, FeCl2 and for FeSO4 are reliable studies and could be used for classification or DNEL derivation. However, iron absorption in the rat is higher than in humans (Mahoney and Hendricks 1984); consequently, rat studies are considered unreliable models for iron toxicology in humans (Reddy 1991).

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LOAEC
1.4 mg/m³
Study duration:
subacute
Species:
rabbit
Quality of whole database:
Good documented scientific paper, but not conclusive for classification or DNEL derivation.

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

This endpoint is covered by the category approach for soluble iron salts (please see the section Toxicokinetics, metabolism and distribution for the category justification/report format).

Table: Overview on available animal data

Iron salt species analysed

Identifier of the study

Klimisch score and relevance

Test method & Animal species

Result based on iron salt

Result based on iron

Oral

FeCl3

Sato 1992a

K2 KS

Repeated dose toxicity: oral, 90 d rat

NOAEL: 277 mg/kg bw in males, 314 mg/kg bw in females

NOAEL: 95 mg/kg bw in males, 108 mg/kg bw in females

FeCl3

Lysogorova 1974

K4 SS

Repeated dose toxicity: oral, 7 months, rat

NOAEL: 0.1 mg/kg bw, LOAEL: 1 mg/kg bw/d (assuming drinking volume of 0.1 L/kg bw/d)

NOAEL: 0.0344 mg/kg bw, LOAEL: 0.344 mg/kg bw/d (assuming drinking volume of 0.1 L/kg bw/d)

FeCl3

Whitehouse 1960

K4 SS

Repeated dose toxicity: oral, 21 d, rat

NOAEL: 760 mg/kg bw

NOAEL: 261.6 mg/kg bw

FeCl3

Akhundov 1983

K4 SS

Repeated dose toxicity: oral, 6 months, rat

NOAEL: 2 mg/kg bw

NOAEL: 0.689 mg/kg bw

FeCl2

Beom 2004

K1 KS

Repeated dose toxicity: oral - OECD 422, rat

NOAEL: 125 mg/kg bw in males, 250 mg/kg bw in females, LOAEL: 250 mg/kg bw in males, 500 mg/kg bw in females

NOAEL: 55.1 mg/kg bw in males, 110.1 mg/kg bw in females, LOAEL: 110.1 mg/kg bw in males, 220.5 mg/kg bw in females

FeSO4 x 7 H2O

Furuhashi 2002

K1 KS

Repeated dose toxicity: oral - OECD 422, rat

NOAEL: 100 mg/kg bw, LOAEL: 300 mg/kg bw/d for the test item; NOAEL: 54.6 mg/kg bw, LOAEL: 163.9 mg/kg bw/d for anhydrous FeSO4

NOAEL: 20.1 mg/kg bw, LOAEL: 60.3 mg/kg bw/d

FeSO4 x 7 H2O

Appel 2001

K2 SS

Repeated dose toxicity: oral, 31 to 61 d , rat

No adverse effects at the highest dose of 31.2 mg/kg bw

No adverse effects at the highest dose of 11.5 mg/kg bw

Inhalation

iron chloride / iron sulphate

Kamil'dzhanov 1985

K3 SS

Repeated dose toxicity: inhalation - 65 d, rat

threshold value: 0.004 mg/m³

FeCl3

Johansson 1992

K2 KS

Repeated dose toxicity, inhalation - 2 months, rabbit

LOAEL: 1.4 mg/m³

KS: key study; K1: reliable without restriction, Klimisch 1; reliable with restriction, Klimisch 2; K3: not reliable, Klimisch 3; K4: not assignable, Klimisch 4

- Repeated dose toxicity, oral:

 • animal data:

  - FeCl3 is deemed not to show classifiable specific target organ toxicity. In a good quality dose range-finding study (reliability score 2, Sato 1992a) in which ferric chloride hexahydrate was administered to Fischer 344 rats (10/sex/dose) in their drinking water for 13 weeks, at concentrations of 0.12, 0.25, 0.5, 1.0 and 2.0 % (equivalent to approximately 80, 154, 277, 550 and 1231 mg/kg bw/day in male rats, 88, 176, 314, 571 and 1034 mg/kg bw/day in female rats). There was a significant reduction in body weight gains at the two highest doses at the end of the treatment period. Treated males had increased levels of serum iron and higher red blood cell counts compared with controls. In microscopic examinations of sections stained with haematoxylin and eosin, brown pigment deposition was observed only in the keratin layers of the oesophageal mucosa in the groups given concentrations of 0.25% or higher, and in the laminae propriae of the large intestine in the 2.0% group. In sections stained with Berlin blue, increased numbers of positive pigments (an indication of iron overload) were also observed in the hepatocytes and Kupffer cells of the liver, the cartilage of the trachea and bronchus, the keratin mucosal layers of the tongue, the forestomach, the mucous layers of the small intestines, the white pulp of the spleen, the tubular epithelium of the kidney and the adipose tissues of the groups given 0.25 % and higher. The intensity of the staining was marked in the intestine and liver. The NOAEL was 0.5 % (equivalent to 277 and 314 mg/kg bw/day in males and females, respectively) based on the reduced body weight gain. Additional studies on FeCl3 are available but as the information given there is in all cases quite limited, they are disregarded for classification and derivation of DNELs.

 - For Fe2(SO4)3 no data is available on this endpoint. Accordingly here a read across from FeCl3 is applied and the substance is deemed not to be classifiable according to CLP.

- FeCl2 is deemed not to show classifiable specific target organ toxicity. One reliable study conducted according to OECD 422 and GLP in rats (Beom 2004) using dose levels of 125, 250 and 500 mg anhydrous FeCl2 /kg bw/day (oral gavage), reporting NOAELs of 125 mg/kg bw in males and 250 mg/kg bw in females and LOAELs of 250 mg/kg bw in males and 500 mg/kg bw in females. Changes in body weight, water consumption, organ weight and histopathology in males at the dose of 500 mg/kg and changes in organ weight at the dose of 250 mg/kg were reported. In females, changes in organ weights and histopathology were observed at the dose of 500 mg/kg. The changes except body weight changes in males seemed to be reversible. In addition the treatment period was from day 0 to 42 in males and from day 0 to 4 post partum in females. Accordingly the extrapolation factor for comparison with subchronic exposure can be reduced to 2.0. The classification limit would therefore be 200 mg/kg bw/d. The LOAEL of 250 mg/kg bw/d surpasses this value and the effects seen at this dose are not classifiable according to section 3.9.2.8. of CLP. Therefore FeCl2 is deemed not classifiable according to CLP. Results on reproductive and developmental toxicity are discussed in chapter 7.8 of the IUCLID 5 dossier and the respective chapter in the CSR.

- FeSO4 is deemed not to show classifiable specific target organ toxicity. One reliable study conducted according to OECD 422 and GLP in rats (Furuhashi 2002) using dose levels of 1, 30, 100, 300, 1000 mg FeSO4 x 7 H2O /kg bw/day (oral gavage). The NOAEL for repeated dose toxicity of iron sulphate heptahydrate was 100 mg/kg bw/day (equivalent to 20 mg Fe/kg bw/day for both sexes) based on the extramedullary haematopoiesis of the spleen in males and increased levels of inorganic phosphate in females at 300 mg/kg bw/day. Based on the relative molecular weight for anhydrous FeSO4 the following values result: NOAEL: 54.6 mg/kg bw, LOAEL: 163.9 mg/kg bw/d.

Even though these effects are sufficient for derivation of a LOAEL, it has to be noted that the effects regarding extramedullary haematopoiesis are only slightly about the background in controls:

Males:

300 mg/kg bw/day: spleen: yellow-brown pigmentation in the red pulp (6 cases); extramedullary haematopoiesis (5 cases) vs. control animals: yellow-brown pigmentation in the red pulp (6 cases); extramedullary haematopoiesis (2 cases)

Females:

300 mg/kg bw/day: spleen: yellow-brown pigmentation in the red pulp (6 cases); extramedullary haematopoiesis (6 cases) vs. Control animals: spleen: yellow-brown pigmentation in the red pulp (6 cases); extramedullary haematopoiesis (6 cases)

Additionally the exposure periods have been significantly longer than 28 d: Males: Total of 49 days beginning 14 days before mating, Females: Total of 42-47 days from 14 days before mating to day 5 of lactation. Accordingly the extrapolation factor for comparison with subchronic exposure can be reduced to 2.0. The classification limit would therefore be 200 mg/kg bw/d. Compared to the LOAEL of 163.9 mg/kg bw/d and with regard to the exclusion criteria described in chapter 3.9.2.8. of CLP (Effects considered not to support classification for specific target organ toxicity following repeated exposure) FeSO4 is deemed not classifiable for specific target organ toxicity according to CLP.

Results on reproductive and developmental toxicity are discussed in chapter 7.8 of the IUCLID5 dossier and the respective chapter in the CSR.

  - For FeClSO4 no data is available on this endpoint. Accordingly here a read across from FeCl3 is applied and the substance is deemed not to be classifiable according to CLP.

 • human data:

- 3 publications on the oral toxicity after repeated exposure are available for iron uptake in general. For the defined members of the iron salts of this category no human data has been identified fort his endpoint.

The Expert Group on Vitamins and Minerals (EVM 2003) has analysed the effects the safety of vitamin and mineral supplements in food and looked at: exposure to iron; the biological function of iron; iron deficiency; interactions with other metals; absorption and bioavailability; distribution, metabolism and excretion; toxicity. Guidance levels were established. The review reported average daily losses of 1.0 mg/day in healthy adult male humans, and 1.3 mg/day in pre-menopausal women. The acute doses were considered to be: 20 mg/kg for infants (under the age of six) by gastrointestinal irritation, with systemic effects not occurring below 60 mg/kg bw; 200-300 mg/kg for children; 1400 mg/kg bw for adults. It was considered that there is not enough evidence to reach conclusions on specific links between iron and development of cancers. Finally it is concluded that for guidance purposes, a supplemental intake of approximately 17 mg/day (equivalent to 0.28 mg/kg bw/day for a 60 kg adult) would not be expected to produce adverse effects in the majority of people. This review summarised a large amount of available publications in human.

Tran (2000) conducted a literature search for relevant English language publications between 1966 and 1998. After exclusion of articles and their references which appeared in peer reviewed publications 14 papers were identified describing 61 incidences of obstetric iron overdose by ingestion. From the data extracted the patients were grouped according to maternal serum iron level either < 400 µg/dL (4000 µg/l) or >= 400 µg/dL (4000 µg/l) and by stage of iron toxicity. Groups were compared for maternal-foetal outcomes which included spontaneous abortion, perinatal death, preterm delivery, congenital abnormalities or maternal death. The same groups were compared for aspects of deferoxamine use. No relationship was found between peak iron level and frequency of spontaneous abortion, preterm delivery, congenital anomalies or perinatal or maternal death. Peak iron levels were available for 23 patients. However patients with peak levels greater than 400 µg/dL were more frequently symptomatic than women with lower peak levels (12/13 compared to 5/10). Patients from both groups were treated similarly for the iron overdose. Iron toxicity could be staged in 59 patients. Patients with stage 3 iron intoxication (organ failure) were more likely to spontaneously abort (1/3 vs 1/56), deliver preterm (2/3 vs 6/56), or experience maternal death 3/3 vs 0/56).

Bothwell (1982) reviewed the relationship of iron losses and iron absorption to iron deficiency. Iron losses in the male are reported as approximately 1 mg/day; in females obligatory losses are approximately 0.8 mg/day, with menstrual losses varying widely, but averaging over the whole cycle at 0.4-0.5 mg/day; women require about 2 mg per day of absorbed iron to remain in iron balance. Iron is absorbed more readily from haem than from cereals, and haem and ascorbic acid promote the absorption of iron from cereals. The incidence of iron overload was discussed. It was concluded that the ingestion of large amounts of bioavailable iron by normal subjects over many years can lead to iron overload. Iron overload also occurs in subjects with hereditary diseases that lead to absorption of inappropriately large quantities of iron.

 • summary of repeated dose toxicity, oral:

The available rat test data for FeCl3, FeCl2 and for FeSO4 are reliable studies and could be used for classification or DNEL derivation. However, iron absorption in the rat is higher than in humans (Mahoney and Hendricks 1984); consequently, rat studies are considered unreliable models for iron toxicology in humans (Reddy 1991). Generally the ferrous salts show a higher toxicity then FeCl3 which is in line with the assumption that the ferrous ion has a significantly higher bioavailability as compared to the ferric ion. Based on data referring to ferrous iron (Fe II), the Expert Group on Vitamins and Minerals (EVM 2003) defined a supplemental iron intake of approximately 17 mg/day (equivalent to 0.28 mg/kg/bw/day for a 60 kg adult). This is derived from human data by dividing the lower end of the range found to have an adverse effect by an uncertainty factor of 3 to allow for extrapolation from a LOAEL to NOAEL. No additional uncertainty factor is needed for inter-individual variation because the assessment is based on studies on large numbers of people (EVM 2003).

 

- Repeated dose toxicity, dermal:

No studies are available.

- Repeated dose toxicity, inhalation:

• animal data:

- FeCl3 is deemed not to have enough evidence to show classifiable specific target organ toxicity. One reliable inhalation study in rabbits (Johansson 2002) was conducted in the similar to OECD TG 413 principles. However, some design gaps were observed: a smaller investigated number of animals, 1/3 shorter exposure duration and 2 instead of 3 exposure groups (1.4 and 3.1 mg Fe/m³). At the end of the study, only local effects in lungs were investigated. The lowest dose of 1.4 mg Fe/m³ was considered by The Health Council of the Netherlands as the LOAEL. It is difficult to describe reversibility of deposed FeCl3 in the lungs, since no recovery group was reported. Therefore this study is disregarded for classification and derivation of DNELs.

One not reliable study (Kamil'dzhanov 1985) reported official Soviet Union threshold values of 0.004 mg/m³ for iron chloride (expressed as iron ion) and of 0.007 mg/m³ for iron sulphate (expressed as iron ion) in residential air. In this study no clear NOAEL was identified, therefore the available data are not sufficient to allow decision on classification after repeated inhalation exposure in rats.

• summary on animal data:

The available data is not sufficient to allow decision on classification for the endpoint inhalation toxicity after repeated exposure.

• human data:

In a study of Kleinman 1981 the respiratory effects of exposure to ferric sulphate aerosol in humans (reliability score 2) volunteers (38) were exposed to 75 µg/m³ aerosol of ferric sulphate (= 20 µg/m³ Fe) for 2 hours on each of 5 days. The investigation was conducted as a double blind study. Subjects served as their own control by blind exposure to 'sham' aerosol. The group average results were contrasted between day (sham or exposure) and conditions (pre- and post-exposure) using a two-way analysis of variance with repeated measure. Only five of the 38 volunteers tested showed patterns indicative of a decrement in pulmonary function. Nine of the subjects exhibited significant improvement in function. None of the subjects reported more than slight changes in symptoms during exposure. The authors considered that the tendency for a subject to improve after the ferric sulphate exposure could be related to allergy status, smoking history, or a combination of these factors. Furthermore, they recorded that “it is encouraging to note that at the relatively high aerosol concentration used in this study, there were no significant detrimental changes in the (study) population as a whole.” The study appears to have been well conducted and the conclusions are consistent with the data presented. It may be assumed that ferric sulphate aerosols do not produce any clear pulmonary effects in either normal persons or asthmatics.

• summary on human data:

The available data is not sufficient to allow decision on classification for the endpoint inhalation toxicity after repeated exposure.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Reliable study according to OECD TG 422. In this study bioavailable Fe2+ (FeCl2) does not show classifiable specific target organ toxicity.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
Only one available study for FeCl3.

Justification for classification or non-classification

- Repeated dose toxicity, oral:

Based on the above stated assessment of the specific target organ toxicity potential after repeated oral exposure of iron salts, none of the members of the iron salt category needs to be classified according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) or according to CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

 

- Repeated dose toxicity, dermal:

As no data on of the specific target organ toxicity potential after repeated dermal exposure of iron salts is available a classification is not possible according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU.

 

- Repeated dose toxicity, inhalation:

As no reliable data on of the specific target organ toxicity potential after repeated inhalation exposure of iron salts is available a classification is not possible according to Council Directive 2001/59/EC (28th ATP of Directive 67/548/EEC) and according to CLP (5th ATP of Regulation (EC) No 1272/2008 of the European Parliament and of the Council) as implementation of UN-GHS in the EU. Therefore the classification statement should be set inconclusive. This is considered acceptable as inhalation is probably not relevant route of exposure and may be excluded in all supported uses.