Potassium iodide

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

no data

Additional information

According annex IX of REACH, this test only need to be triggered in case that any reproductive or developmental alert was found in repeated toxicity test or developmental test. Existing repeated toxicity tests and developmental tests all gave no such concern. Therefore reproductive toxicity test can be omitted.

According to REACH Annex IX 8.7 thestudies need not be conducted if:

 the substance is of low toxicological activity (no evidence of toxicity seen in any of the tests available), it can be proven from toxicokinetic data that no systemic absorption occurs via relevant routes of exposure (e.g. plasma/blood concentrations below detection limit using a sensitive method and absence of the substance and of metabolites of the substance in urine, bile or exhaled air) and there is no or no significant human exposure.

Short description of key information:
It can be concluded that the iodide is not reproductive toxicity.

Effects on developmental toxicity

Description of key information

It can be concluded that the iodide is not reproductive, embryonic or developmental toxicity.

Effect on developmental toxicity: via oral route

Dose descriptor:

NOAEL

50 mg/kg bw/day

Additional information

Potassium iodide (KI) was fed to male and female rats before and during breeding, to females only during gestation and lactation, and to their offspring after weaning (day 21 after birth) through to day 90, at levels of 0, 0.025, 0.05 or 0.1% (w/w) of the diet.

There was no evidence suggesting that potassium iodide was embryotoxic. Litter size was significantly reduced, but birth weights and external morphology among those born alive were not significantly altered.

No change in thyroid weight was observed indicating that these doses were not overtly thyrotoxic. Thyroid hormones were not assessed, however, and it is possible that thyroid function could have been altered in these animals. Nevertheless, the data are consistent with a picture of impaired thyroid function.
Several tests of post-weaning behaviour showed effects at the lowest dose, 0.025 % potassium iodide. M-maze errors were increased at this dose and rotorod performance decreased. However, because these effects were not found at the higher doses it appears unlikely that they were related to potassium iodide. At present, these effects can only described as 'false positives'.
The only effect on post-weaning behaviour that appeared to be consistently related to potassium iodide exposure was the reduction in nocturnal running-wheel activity found among the tested females. It may be that female cyclicity makes them more sensitive to the influence of chronic moderate iodide exposure than males and this could explain the contrast with the results of an acute test of activity and exploration, the open-field test, on which no consistent iodide-related effects were found.

According to REACH guidance “R 10.8 of Guidance on information requirements and chemical safety assessment Chapter R.10: Characterisation of dose [concentration]-response for environment” The NOAEL can be calculated with the equation R 10-7:NOAEL(mg/kg bw day) = NOEC (mg/kg food)/CONV

Where NOEC (mg/kg food) is 0.1, and CONV for Rattus norvegicus (> 6 weeks) is 20, and 10 for Rattus norvegicus (≤6 weeks). Therefore under this study the NOAEL for rats is 50 mg/kg bw day (developmental).

In another study, twenty-five thyroiditis-prone BB/W rats were prenatally and postnatally exposed to iodine in drinking-water at dosages equivalent to 0, 0.059, or 59 mg/kg body weight per day for about 12 weeks. An increase in the number of lysosomes and lipid droplets was observed in the treated animals, especially in the higher exposure group. However, the test organism is not healty, as well as not enough information in the study, the effects can not be considered to be dose related.

Additionally, old studies were conducted with rabbits hamsters, rats and swine (Arrington LR, et al., 1965) to determine the effects of excess iodine intake. Females were bred to normal males, potassium or sodium iodide were added to the diet during the latter portion of gestation and the females were permitted to litter normally. Observations were made for length of gestation, parturition time, lactation and survival of young.

250 to 1000 ppm iodide fed for 2 to 5 days caused increasing mortality of new born rabbits. Hamsters were not affected by 2500 ppm iodine except for slightly re duced feed intake and decreased weaning weight of the young. Gestation time for rats and hamsters was not affected by iodine. Female rats and rabbits re-bred after removal from dietary iodine produced and nursed litters normally. Swine were not affected by dietary levels of iodine which were toxic to rabbits and rats.

In conclusion, the iodide is not reproductive, embryonic toxicity, but the developmental toxicity was showed under concentration of 0.1% in diet, corresponding NOAEL as 50 mg/kg bw day (developmental).

Toxicity to reproduction: other studies

Additional information

no data

Justification for classification or non-classification

Based on this information, the iodide is not reproductive, embryonic toxicity, but the developmental toxicity was showed under concentration of 0.1% in diet, corresponding NOAEL as 50 mg/kg bw day (developmental). However, this value is much higher than the temporary most tolerated dose of 1.0 mg iodine/day, set by the FAO/WHO Joint Expert Meeting on Food Additive (the 30th Meeting of the Joint FAO/WHO Expert Committee on Food Additives,, 2±11 June 1986, 1987).

Therefore, the iodide can not meet the reproductive/developmental criteria under the Regulation (EC) No. 1272/2008 nor Directive 67/548/EEC.