Copper iodide

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

COPPER IODIDE

Copper iodide will dissociate following exposure via the inhalation, oral or dermal routes, giving rise to cuprous copper ions (Cu+) and iodide ions (I-) that will be more bioavailable than the parent compound. These ionic species will be independently responsible for any effects seen in the event that organisms are exposed to copper iodide as a result of its production and/or use.

Copper is an essential element, with many countries recommending an increased dietary intake of copper during pregnancy. The existing data base is sufficient to adequately evaluate the reproductive and developmental toxicity of copper and to conclude that copper and copper compounds do not need to be classified on this basis.

 

Reproductive and developmental effects associated with iodine have been described as secondary to thyroid impairment. It is considered that establishing safety levels to prevent thyroid imbalance in the mothers is considered sufficiently protective and that it is not appropriate to classify iodine on the basis of reproductive or developmental toxicity.

 

In view of the above it is concluded that copper iodide should not be classified as a reproductive toxicant.

 

Summary information on the effect of copper and iodine on fertility is presented below.

COPPER:

Short description of key information:

The two-generation study in the rat indicate that that under the conditions of this study, the no-observed-adverse-effect level (NOAEL) for reproductive toxicity was 1500 ppm, the highest concentration tested. The NOAEL for P1 and F1 rats and F1 and F2 offspring during lactation was 1000 ppm, based on reduced spleen weight in P1 adult females, and F1 and F2 male and female weanlings at 1500 ppm however the transient reduced spleen weights are not considered a reproductive endpoint as it did not affect growth or fertility. In compliance with the “Definition of reproductive toxicity”, OECD document ENV/JM/MONO(2001)6 the spleen effect cannot be considered a reproductive effect as this must include: - Adverse effects on sexual function and fertility in adult males and females - Developmental toxicity in the offspring For a compound to be considered to be a reproductive toxin “data for animal studies ideally should provide clear evidence of specific reproductive toxicity in the absence of other, systemic, toxic effects”. Therefore as the results of this study do not indicate specific reproductive toxicity at the highest dose level tested, it is proposed that copper sulphate and, after read across, copper are not classified as reproductive compounds.

Effect on fertility:

Effect on fertility via oral route:

Effect level: NOAEL 24 mg/kg/ bw/day.

Discussion:

Non human information

 

Available public domain studies on the fertility of copper, taken in isolation are of limited value to ascertain the reprotoxic potential copper compounds over multi-generations. These studies have been given lower quality criteria than those summarised above and should not be used for either risk assessment purposes or to classify copper compounds. However, the VRAR, 2008 provides a full review of these studies and the discussion on the unsuitability/unacceptability of these studies.

 

Method	Results	Remarks	Reference
rat (Crl:CD®(SD)IGS BR) male/female two-generation study oral: feed 0, 100, 500, 1000, 1500 ppm (nominal in diet) Exposure: Duration of exposure before mating: At least 70 days for both P1 and F1 animals. See Other information - Table 5. EPA OPPTS 870.3800 (Reproduction and Fertility Effects) OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)	LOAEL (P): > 1500 ppm (male) based on: test mat. (No reproductive toxicity was seen at any concentration.) LOAEL (P): 1500 ppm (female) based on: test mat. (Decreased spleen weight in P1 adult females. No reproductive toxicity was seen at any concentration.) LOAEL (F1): 1500 ppm (male) based on: test mat. (Decreased spleen weight in F1 male weanlings. No reproductive toxicity was seen at any concentration.) LOAEL (F1): 1500 ppm (female) based on: test mat. (Decreased spleen weight in F1 female weanlings. No reproductive toxicity was seen at any concentration.) LOAEL (F2): 1500 ppm (male) based on: test mat. (Decreased spleen weight in F2 male weanlings.) LOAEL (F2): 1500 ppm (female) based on: test mat. (Decreased spleen weight in F2 female weanlings.) NOAEL (P): 1500 ppm (male) based on: test mat. (Equivalent to 23.6 mg Cu/kg bw/day for P1 males during premating.) NOAEL (P): 1000 ppm (female) based on: test mat. (No reproductive toxicity was seen at any concentration. Equivalent to 19.1, 17.0 and 33.8 mg Cu/kg bw/day for P1 females during premating, gestation and the first 2 weeks of lactation, respectively.) NOAEL (F1): 1000 ppm (male) based on: test mat. (No reproductive toxicity was seen at any concentration. Effects were seen in F1 weanlings. Equivalent to 23.5 mg Cu/kg bw/day for adults at 1000 ppm.) NOAEL (F1): 1000 ppm (female) based on: test mat. (No reproductive toxicity was seen at any concentration. Effects were seen in F1 weanlings. 1000 ppm is equivalent to 26.7, 17.1 and 35.2 mg Cu/kg bw/day for F1 females during premating, gestation and the first 2 weeks of lactation, respectively.) NOAEL (F2): 1000 ppm (male) based on: test mat. (No reproductive toxicity was seen at any concentration. Effects were seen in F2 weanlings.) NOAEL (F2): 1000 ppm (female) based on: test mat. (No reproductive toxicity was seen at any concentration. Effects were seen in F2 weanlings.)	1 (reliable without restriction) key study experimental result Test material (common name): Cu2+ ascopper sulphate pentahydrate	Mylchreest E. (2005)

 

The results of Mylchreest, 2005 indicate that under the conditions of this study, the no-observed-adverse-effect level (NOAEL) for reproductive toxicity was 1500 ppm, the highest concentration tested. The NOAEL for P1 and F1 rats and F1 and F2 offspring during lactation was 1000 ppm, based on reduced spleen weight in P1 adult females, and F1 and F2 male and female weanlings at 1500 ppm however the transient reduced spleen weights are not considered a reproductive endpoint as it did not affect growth or fertility.

In compliance with the “Definition of reproductive toxicity”, OECD document ENV/JM/MONO(2001)6 the spleen effect cannot be considered a reproductive effect as this must

include:

• Adverse effects on sexual function and fertility in adult males and females
• Developmental toxicity in the offspring

For a compound to be considered to be a reproductive toxin “data for animal studies ideally should provide clear evidence of specific reproductive toxicity in the absence of other, systemic, toxic effects”. Therefore as the results of this study do not indicate specific reproductive toxicity at the highest dose level tested, it is proposed that copper sulphate and copper are not classified as toxic to reproduction.

IODINE:

Short description of key information:

One reliable (OECD guideline study, GLP) screening test on reproduction/developmental effects of iodine: NOAEL 10 mg/kg bw/day (no effects on reproduction and/or development).

Effect on fertility

Effect on fertility via the oral route

Effect level: NOAEL 10 mg/kg bw/day Discussion: Discussion:

The effects of iodine on human reproduction are well known from literature data. Exposure to excess iodine may produce hypothyroidism or hyperthyroidism and could cause disruption of reproductive function, secondary to thyroid gland dysfunction. Hypothyroidism can produce changes in the menstrual cycle in humans, including menorrhagia (excessive uterine bleeding) and anovulation (no ovulation). Spontaneous abortions, stillbirths, and premature births have also been associated with hypothyroidism. Reproductive impairments associated with hyperthyroidism include amenorrhea and alterations in gonadotropin release and sex hormone-binding globulin (SHBG), and associated changes in the levels and metabolism of steroid hormones in both females and males (ATSDR, 2004).

The conduct of additional studies in laboratory animals would not add new information to the data package for iodine.

As reproduction impairment is secondary to thyroid dysfunction, the safety levels set for repeated dose toxicity are considered sufficiently protective to reproductive effects following excess iodine exposure.

References:

- Agency for Toxic Substances and Disease Registry (ATSDR). 2004. Toxicological profile for iodine.

Effects on developmental toxicity

Additional information

COPPER IODIDE

Copper iodide will dissociate following exposure via the inhalation, oral or dermal routes, giving rise to cuprous copper ions (Cu+) and iodide ions (I-) that will be more bioavailable than the parent compound. These ionic species will be independently responsible for any effects seen in the event that organisms are exposed to copper iodide as a result of its production and/or use.

Copper is an essential element, with many countries recommending an increased dietary intake of copper during pregnancy. The existing data base is sufficient to adequately evaluate the reproductive and developmental toxicity of copper and to conclude that copper and copper compounds do not need to be classified on this basis.

 

Reproductive and developmental effects associated with iodine have been described as secondary to thyroid impairment. It is considered that establishing safety levels to prevent thyroid imbalance in the mothers is considered sufficiently protective and that it is not appropriate to classify iodine on the basis of reproductive or developmental toxicity.

 

In view of the above it is concluded that copper iodide should not be classified as a reproductive toxicant.

 

Summary information on the developmental toxicity of copper and iodine is presented below.

COPPER:

Short description of key information:

The existing data base is sufficient to adequately evaluate the developmental toxicity of copper with particular reference to the newly available two-generation study in the rat. It is therefore considered inappropriate to consider copper and copper compounds as potential teratogenic compounds due to the complex role of copper in regulating normal foetus development in humans at levels considered higher than would be expected to occur through the normal production and use of any copper compound.

Discussion:

Non-human information

Method	Results	Remarks	Reference
rabbit (New Zealand White) oral: gavage 6, 9, or 18 mg Cu/kg bw/day (analytical conc.) Exposure: Duration of exposure: Day 7–28 of gestation. OECD Guideline 414 (Prenatal Developmental Toxicity Study) EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study) MAFF guideline 59 NohSan Np. 4200 (1985) EU Method B.31 (Prenatal Developmental Toxicity Study)	Maternal toxicity reported at 9 mg/kg bw/d (inappetance and initial weight loss) and 18 mg/kg bw/d (deaths, weight loss). Effects on fetus (increased incidence of some common skeletal variants and 9 and 18 mg/kg d.   NOAEL maternal toxicity 6 mg/kg bw/day   NOAEL teratogenicity 6 mg/kg bw/day   Results discussed in more detail below.	1 (reliable without restriction) key study experimental result Test material (Common name): Copper hydroxide	Munley, S.M. (2003a)

 

In the developmental toxicity study (Munley 2003), groups of 22 female NZW rabbits were treated orally by gavage on days 7 to 28 of pregnancy with copper hydroxide (0, 6, 9 or 18 mg Cu/kg/bw/day). A preliminary range-finding test, conducted in non-pregnant rabbits, indicated there were no marked differences between several copper compounds (including copper hydroxide, copper (I) oxide and copper oxychloride) in terms of maternal toxicity. In the main study, maternal toxicity was evident at 9 and 18 mg Cu/kg/bw/day. Initial weight loss and reduced food intake occurred at 9 and 18 mg/kgBW/day, followed by partial recovery during the middle/late pregnancy. At the end of the study, bodyweight gain in these two groups was 31% and 72% lower than controls and total food consumption 17% and 30% lower than controls, respectively. Three deaths and two abortions occurred at 18 mg/kgBW/day which appeared to be related to treatment; necropsy of decedents and one aborted animal showed haemorrhagic and/or ulcerative changes in the stomach lining. No deaths occurred at 9 or 6 mg/kg/bw/day. At 9 mg/kg/bw/day, there were no abortions. At 6 mg/kg/bw/day, there was a single abortion on day 27. This abortion was not considered to be treatment-related in view of the absence of abortions at the higher dose level and earlier occurrence of abortions at 18 mg/kg/bw/day. At 6 mg/kg/bw/day, and bodyweight gain and food intake were only marginally lower than controls. There was no difference between treatment groups and controls in the number of pregnant females, or the number of females showing total resorption or with live offspring. There was no difference between treatment and control groups in the number of corpora lutea, implantations, embryonic deaths, live young or percentage of males in litter. At 18 mg/kg/bw/day, mean fetal weight was slightly lower than in controls (9% less). Four malformed fetuses occurred in the study: one with fused ribs (control group); one with ectopic kidney (6 mg/kg/bw/day); two with hemivertebra (18 mg/kg/bw/day). These malformations were all considered to be unrelated to treatment. With regard to fetal skeletal abnormalities, retarded ossification of pelvis and skull showed a slightly increased incidence at 18 mg/kg/bw/day and occurrence of extra ribs was increased at 9 and 18 mg/kg/bw/day compared to controls. It was noted that the occurrence of extra ribs was a common finding in all treatment groups, including the control group (64%, 67%, 80% and 87% incidence at 0, 6, 9 and 18 mg/kg/bw/d, respectively). With regard to fetal visceral abnormalities, none were recorded for any treatment or control group.  In conclusion, this study demonstrated maternal toxicity (initial weight loss and reduced food intake) and effects on the fetus (increased incidence of a common skeletal abnormality) following oral exposure of rabbits to copper hydroxide at 9 mg Cu/kg/bw/day and above during pregnancy. There were no indications of fetal abnormalities associated with treatment at up to maternally toxic levels. The NOAEL for maternal toxicity and developmental effects in rabbits in this study was 6 mg Cu/kg/bw/day. Effects on the fetus were considered to be secondary to maternal toxicity and consequently not a specific effect of copper on reproduction. 

Maternal toxicity, reported in this study at 9 mg/kg/bw/day, was represented by initial weight loss. These effects are considered to be local effects on the stomach in rabbits which result from gavage administration of copper hydroxide. Consequently, it is considered inappropriate to use data on maternal toxicity from this study as the basis of a repeat-dose NOAEL for copper.

With the addition of the multi generation study to the existing toxicology data base it is considered that sufficient information is now available to adequately evaluate the developmental toxicity potential of copper. The Mychreest, 2005 study (summarised above) is particularly relevant as the rat is considered the best animal model for evaluating the potential hazard effects on human populations.

The 2 generation oral reproduction study, performed in accordance with OECD test guideline 416, provides information on the effects of repeated exposure to the substance during all phases of the reproductive cycle including gestation. In particular, the study provides information on the reproductive parameters, and on development, growth and survival of offspring.

The NOAEL for reproductive toxicity was 1500 ppm, the highest concentration tested. The NOAEL for P1 and F1 rats and F1 and F2 offspring during lactation was 1000 ppm, based on reduced spleen weight in P1 adult females, and F1 and F2 male and female weanlings at 1500 ppm. However the transient reduced spleen weights were not considered a reproductive endpoint as it did not affect growth and fertility.

In compliance with the “Definition of reproductive toxicity”, OECD document ENV/JM/MONO(2001)6 the spleen effect cannot be considered a reproductive effect as this must include:

• Adverse effects on sexual function and fertility in adult males and females
• Developmental toxicity in the offspring

For a compound to be considered to be a reproductive toxin “data for animal studies ideally should provide clear evidence of specific reproductive toxicity in the absence of other, systemic, toxic effects”

The dietary concentration of 1000 ppm was equivalent to mean daily intakes of copper of 15.2-23.5 mg/kg body weight/day for male rats during premating and 17.0-35.2 mg/kg body weight/day for female rats during premating, gestation and the first 2 weeks of lactation.

Although the principal aim of this study was to investigate reproduction toxicity it also provides important information on the developmental toxicity potential of the test substance. Notably, investigation of F1 and F2 litters showed no test substance related effects on the following parameters:

• pups survival, sex ratio, and survival indices during the lactation period, body weights and clinical observations during lactation,
• macroscopic examination of pups that died during the lactation period, of weanlings with external abnormalities or clinical signs and of randomly selected weanlings,
• microscopic observations of any gross findings and of liver and brain from randomly selected high-dose and control weanlings.

It is therefore considered that all major manifestations of developmental toxicity (including mortality, structural abnormality, altered growth and functional deficiency) are adequately investigated in this study.

The results of the multigeneration study should also be interpreted in conjunction with the rest of the toxicology data base for copper. The following findings are considered relevant when evaluating the reproductive and developmental toxicity potential of the test substance:

• Subchronic and chronic studies show no adverse effects on reproductive organs or endocrine functions,
• Copper salts show no indication of genotoxicity,

It is also important to consider that copper is an essential element and many countries recommend an increased dietary intake of copper during pregnancy. This increased recommendation is because a foetus requires copper levels up to 10 times adult levels. The copper is absorbed across the placenta and is required for healthy growth and development, especially in blood maturation, bone development, heart development and function, brain development and function and the function of 20 key enzymes (Ralph & McArdle, 2001).

The existing toxicology data package therefore supports the conclusion that copper has no reproductive or developmental toxicity potential.

IODINE:

Short description of key information:

One reliable (OECD guideline study, GLP) screening test on reproduction/developmental effects of iodine: NOAEL 10 mg/kg bw/day (no effects on reproduction and/or development).

One published study on the developmental effects of chronic exposure to high doses of iodine: LOAEL 1500 µg/L (fetotoxicity)

Effect on developmental toxicity via the oral route:

Effect level: NOAEL 10 mg/kg bw/day

Discussion:

The teratogenic/developmental secondary to excess and deficiency of iodine in humans subjects are well known from literature data.

Human case reports show that highly excessive intake of iodine (lowest reported dose 130 mg/day) during pregnancy may result in neonatal goitre/hypertrophy (WHO, 2009). This could be explain by the fact that excess iodine is transferred via the placenta resulting in the fetal exposure to iodine overload (Sun and Yang, 2009).

The US Agency for Toxic Substances and Disease Register (2004) has reviewed in extent the information available on developmental effects of iodine:

"Exposure to excess stable iodine may produce hypothyroidism and hyperthyroidism, which could give rise to developmental defects secondary to thyroid gland dysfunction (Boyages 2000a, 2000b). Hypothyroidism may be associated with impairment in neurological development of the fetus or growth retardation (Boyages 2000a, 2000b; Snyder 2000a). Martin and Rento (1962) reported two cases of goiter and severe transient hypothyroidism, without neurological sequellae in infants born to mothers who ingested potassium iodide during pregnancy; the approximate dosages were 920 and 1,530 mg I/day (13 and 22 mg/kg/day). Growth acceleration may occur in childhood hyperthyroidism, which is thought to be related to accelerated pituitary growth hormone turnover or a direct effect of thyroid hormone on bone maturation and growth (Snyder 2000b).

Although iodine excess may result in hypothyroidism, iodine deficiency is far more likely to cause prenatal and postnatal hypothyroidism and be associated with neurologic injury leading to cretinism, a developmental effect. Thyroid hormone deficiency from any cause at critical times of development may result in severe mental retardation, neurologic abnormalities, growth retardation, or abnormal pubertal development."

The conduct of additonal studies in laboratory animals would not add new information to the data package for iodine.

As developmental effects have been described as secondary to thyroid impairment, establishing safety levels to prevent thyroid imbalance in the mothers is considered sufficiently protective.

References:

- Agency for Toxic Substances and Disease Registry (ATSDR). 2004. Toxicological profile for iodine.

- Sun, X.F., Yang, X.F. 2009. Developmental effects of toxic doses of iodine. In: “Comprehensive handbook of iodine: nutritional, biochemical, pathological and therapeutic aspects”. USA.

- World Health Organization (WHO). 2009. Iodine and inorganic iodides. In: Concise International Chemical Assessment Document 72.