Potassium nitrite

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Link to relevant study records

Reference

Endpoint:

fertility, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from a study report.

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)

Principles of method if other than guideline:

According to OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Details on species / strain selection:

The Rat is a commonly used species for toxicity studies and is also recommended by the stated regulatory guidelines.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Inbred animals of animal house facility, of the CRO were used after accuring CPCSEA approval.
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: 6-7 weeks
- Weight at study initiation: Males: 206.20 g
Females: 203.60 g
- Fasting period before study: Yes.
- Housing: A total 2-3 rats were housed in each polycarbonate cage (size 37 [cm] x 21 [cm], height 20 [cm]). Cage rotation in every rack was carried weekly once. Sterilized corn-cob produced from pure corn, dried and free from dust, was used as bedding material. It was renewed as often as necessary to keep the animals dry and clean.
- Diet (e.g. ad libitum): A conventional laboratory pellet diet. was offered ad libitum. The copy of composition, microbial and chemical contaminant reports analysed periodically.
- Water (e.g. ad libitum): Aquaguard filtered drinking water in bottles was offered ad libitum. Samples of the drinking water were subjected periodically to bacteriological tests and to chemical contaminant analysis.
- Acclimation period: 7-8 days

DETAILS OF FOOD AND WATER QUALITY: No Data Available

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.60 and 23.20°C
- Humidity (%): 40.60 to 66.10%
- Air changes (per hr): 12 times per hour
- Photoperiod (hrs dark / hrs light): 12 hours light and 12 hours dark.

IN-LIFE DATES: From: February 15, 2019
To: April 06, 2019

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

The oral route was selected for the dose administration and recommended by the regulatory guideline.

Details on mating procedure:

No Data Available

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentration and homogeneity assessment of the dose formulation of Sodium Iodide (CAS No.: 7681-82-5) was performed on Day 01 and Day 22. The results of the analyzed formulation were 3.65, 7.34 and 14.72 mg/ml for Day 01 and 3.65, 7.26 and 14.48 mg/ml for Day 22 for low, mid and high dose respectively. Dose concentration verification were within the acceptance limits of ± 20% of the nominal concentrations for all the dose formulation analysis.

Duration of treatment / exposure:

28 days with 14 days recovery period

Frequency of treatment:

Once Daily

Details on study schedule:

No Data Available

Dose / conc.:

0 mg/kg bw/day

Remarks:

Control Group

Dose / conc.:

0 mg/kg bw/day

Remarks:

Control Group (Recovery)

Dose / conc.:

37.5 mg/kg bw/day

Remarks:

Low Dose Group

Dose / conc.:

75 mg/kg bw/day

Remarks:

Mid Dose Group

Dose / conc.:

150 mg/kg bw/day

Remarks:

High Dose Group

Dose / conc.:

150 mg/kg bw/day

Remarks:

High Dose Group (Recovery)

No. of animals per sex per dose:

G1 (Control Group): 5 males and 5 females
G2 (Low Dose Group): 5 males and 5 females
G3 (Mid Dose Group): 5 males and 5 females
G4 (High Dose Group): 5 males and 5 females
G1-R (Control Recovery Group): 5 males and 5 females
G4-R (High Dose Recovery Group): 5 males and 5 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The doses were selected based upon previously performed Dose-Range FInding Study for the test chemical.
- Rationale for animal assignment (if not random): Prior to the first day of dosing, male and female animals were separately randomized into four different test groups, based on the most recent body weight, using validated software.
- Fasting period before blood sampling for clinical biochemistry: Animals were fasted overnight prior to blood collection.
- Rationale for selecting satellite groups: The satellite group was selected as per the requirement of regulatory guideline.
- Post-exposure recovery period in satellite groups: 2 weeks
- Section schedule rationale (if not random): N/A
- Other: N/A

Positive control:

No Data Available

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Once Daily, preferably at the same time.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: On treatment Day 1 and weekly thereafter during experimental period.

BODY WEIGHT: Yes
- Time schedule for examinations: At start of treatment and weekly (± 2 days) thereafter, till the end of experimental period.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes, at start of treatment and weekly (± 2 days) thereafter, till the end of experimental period.
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Not specified
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not specified

FOOD EFFICIENCY: Not Specified
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Not specified

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Not specified
- Time schedule for examinations: Not Specified

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: During week 4th for main group animals.
- Dose groups that were examined: High dose and control group animals for main group.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: On the termination day, just prior to necropsy.
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Yes
- How many animals: All animals were subjected to blood collection.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: On the termination day, just prior to necropsy.
- Animals fasted: Yes
- How many animals: All animals were subjected to blood collection.

URINALYSIS: Yes
- Time schedule for collection of urine: At the last week of the treatment and recovery periods, all surviving rats of main groups and recovery groups were housed in metabolic cages overnight for collection of urine.
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Functional Observation Battery/ Neurobehavioral Observation, sensory reactivity to stimuli, assessment of grip strength, hind limb foot splay and motor activity assessment was performed in week 4th for main group animals and in week 6th for recovery group animals.
- Dose groups that were examined: All animals were subjected to Neurobehavioural examinations.
- Battery of functions tested: sensory activity / grip strength / motor activity / other: hind limb foot splay

IMMUNOLOGY: No
- Time schedule for examinations: N/A
- How many animals: N/A
- Dose groups that were examined: N/A

OTHER:
Oestrus Cycle: At termination, the oestrus cycle of all females were determined by taking vaginal smears.
Bone Marrow Smear Examination: Bone marrow smear (from femur) were prepared at the time of necropsy.

Oestrous cyclicity (parental animals):

At termination, the oestrus cycle of all females were determined by taking vaginal smears.

Sperm parameters (parental animals):

No Data Available

Litter observations:

No Data Available

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes, all surviving animals from main group were sacrificed on Day 29 and from recovery group were sacrificed on recovery Day 15. All surviving animals (main and recovery groups) were subjected to necropsy and detailed gross pathology evaluation. Animals were fasted overnight before necropsy. Animals were weighed, euthanized by CO2 asphyxiation and examined externally. All orifices and the cranial, thoracic and visceral cavities were opened and examined macroscopically.

HISTOPATHOLOGY: Yes, full histopathology was carried out on the preserved organs and tissues of all animals in the control and high dose groups. Histopathology was not extended to lower dose groups and recovery group, as there is no test item related lesions observed in control and high dose groups.

Postmortem examinations (offspring):

No Data Available

Statistics:

Raw Data were processed using Statistical Software Sigma Plot 14.0. The mean and Standard Deviation were calculated using the software and all data were summarized in tabular form. All continuous data (body weight, percent change in body weight with respect to day 1, feed consumption, functional observation battery/neurobehavioral observation, foot splay record, grip strength, motor activity, haematology, clinical chemistry, absolute and relative organ weights, etc.) were checked for their normality and for homogeneity, and analysed using one-way ANOVA for comparison of means. Heterogneous data was analysed using Dunnett’s test. In case of recovery groups, means were compared using t-test for homogeneous data and Mann Whitney’s test for heterogeneous data. The significane threshold for all tests (p value) was set at 0.05. Significant differences obtained from the statistical analysis have been indicated at the relevant places in this report.

Reproductive indices:

No Data Available

Offspring viability indices:

No Data Available

Clinical signs:

no effects observed

Description (incidence and severity):

No treatment related clinical signs were noted upto 150.0 mg/kg body weight in either sex.

Dermal irritation (if dermal study):

not specified

Mortality:

no mortality observed

Description (incidence):

No morbidity or mortality were detected in animals of any of the experimental groups throughout the duration of the experiment.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males: Treatment related mean body weight and body weight gain (percent change in body weight with respect to Day 1) decrease were noted in males at 150.0 mg/kg when compared to concurrent control animals on Day 8, 15, 22 and 28 in all the groups. . Statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted in males on Day 8 (-42% at 150.0 mg/kg), on Day 15 (upto -44% at 37.5, 75.0 and 150.0 mg/kg), on Day 22 (upto -34% at 37.5, 75.0 and 150.0 mg/kg) when compared to concurrent control animals. In recovery males statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted on Day 8 (-60% at 150.0 mg/kg), Day 15 (-32% at 150.0 mg/kg) and on Day 28 (-28% at 150.0 mg/kg) when compared to concurrent recovery control animals.

Females: No treatment related changes were noted in females in mean body weight and percent change in body weight with respect to Day 1 upto 150.0 mg/kg

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No treatment related effect on food consumption was noted up to 150.0 mg/kg

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No ophthalmological abnormalities were detected in the control (G1) and high-dose (G4) groups at week 4 in either sex.

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically significant increase were noted in RBC, Hematocrit and Hemoglobin of males in G3 and G4 groups, while whereas statistically significant decrease in levels of MCH in males of G2 and G3 group, MCHC in G2 males and WBC in females of G4 group. when compared to concurrent control animals. In recovery animals, statistically significant increase were noted in MCV and MCH (Female: G4-R at 150 mg/kg body weight) while statistically significant decrease were noted in RBC and Platelets (Female: G4-R at 150 mg/kg body weight) when compared to concurrent recovery control animals. The observed variations in hematology parameters at the end of treatment and treatment free period, considered as an inconsistence with dose related response in either sex, reversed in recovery group, minimal in nature and it was further not evidenced by histopathological observations.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

Statistically significant increase were noted in Creatinine in males of G2 groups, Glucose in males of G3 and G4 group, Globulin of females in G2 group when compared to concurrent control animals. In recovery animals, statistically significant increase were noted in ALT and Cholesterol in males of high dose recovery group, while statistically significanct decreased was noted in Phosphorus in males of high dose recovery group, when compared to concurrent recovery control animals. The observed variations in biochemical parameters at the end of treatment and treatment free period, considered as an inconsistence with dose related response in either sex, reversed in recovery group, minimal in nature and it was further not evidenced by histopathological observations.

Urinalysis findings:

no effects observed

Description (incidence and severity):

No treatment related changes were noted in urine analysis upto 150 mg/kg body weight in either sex of treated and treatment free groups.

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

No treatment-related changes were noted in functional observational battery/neurobehavioral observation upto 150.0 mg/kg. Mean foot splay of all dose groups was also found comparable to the control mean. Motor activity measurements revealed statistically significant decreases in Horizontal Count (HC) and in Ambulatory Count (AC) at 150.0 mg/kg in female. This changes were not related to treatment, as it was inconsistent, not dose dependent manner and observed only in single sex.

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

No treatment related histopathological findings were observed in vehicle control group and in high dose group animals. Microscopic examination revealed varying degree of different pathological changes in various organs belonging to control and treatment groups as follows:
Liver: focal to multifocal minimal perivascular lymphocytic infiltrate (Male: G4: 2/5; Female: G1: 2/5; G4: 2/5);
Kidneys (Unilateral): focal mild lymphocytic infiltrate (Male: G1: 1/5; Female: G1: 1/5; G4: 1/5) ;
Thyroid: Congenital cyst (Male: G1: 1/5, G4: 2/5; Female: G1:1/5, G4:: 1/5)
Testes(Unilateral): focal minimal to diffuse moderate multinucleated giant cell ( G1: 1/5, G4:1/5);
Epididymis(Unilateral): focal mild sperm stasis ( G4:2/5).
All the other histopathological changes observed during the study were considered as spontaneous and incidental to Wistar Rats

Histopathological findings: neoplastic:

not specified

Other effects:

no effects observed

Description (incidence and severity):

Bone Marrow smear did not show any adverse effects or deviation as compared to controls.

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

No abnormalities detected in the oestrus cycle in any of the treatment group at termination.

Reproductive function: sperm measures:

not specified

Reproductive performance:

not specified

The test chemical did not cause any systemic toxicity to the animals. However, significant differences in the body weights were observed even in recovery periods. The test chemical also had effects on the weight of organs especially epididymides in males, wherein reduction of organ weight was observed. However, in absence of any histopathological evidence, the effect was considered as non-significant and inconsistent. However, reduction of body weight was considered to be related to the treatment of the test chemical, Sodium Iodide.

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

mortality

body weight and weight gain

food consumption and compound intake

ophthalmological examination

haematology

clinical biochemistry

urinalysis

organ weights and organ / body weight ratios

gross pathology

histopathology: non-neoplastic

reproductive function (oestrous cycle)

other: No adverse effect during bone marrow smear examinations were observed in both males and females.

Remarks on result:

not determinable due to absence of adverse toxic effects

Dose descriptor:

LOAEL

Effect level:

150 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Remarks on result:

not determinable due to absence of adverse toxic effects

Critical effects observed:

no

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality / viability:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Sexual maturation:

not specified

Anogenital distance (AGD):

not specified

Nipple retention in male pups:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings:

not specified

Other effects:

not specified

Behaviour (functional findings):

not specified

Developmental immunotoxicity:

not specified

Remarks on result:

not measured/tested

Critical effects observed:

not specified

Reproductive effects observed:

no

Treatment related:

no

Conclusions:

Based on all the available data, and from the observations and conclusion, the NOAEL and LOAEL for the test chemical, Sodium Iodide (CAS No. 7681-82-5) was found to be 75 mg/kg bw/day and 150 mg/kg bw/day, respectively.

Executive summary:

A 28 days repeated dose toxicity study was performed using the test chemical, Sodium Iodide (CAS No. 7681-82-5). Wistar rats were used as animals of choice, wherein the test chemical was dosed to the rats for 28 days with 14 days recovery period. A total number of 60 Wistar rats (30 males and 30 females) were randomly allocated to six different dose groups of 5 animals/sex/group. The animals allocated to Group G2, G3 and G4/G4-R received 37.5, 75.0and 150.0mg/kg body weight of Sodium Iodide (CAS No.: 7681-82-5) respectively, whereas the animals of Group G1/G1-R, received vehicle alone [Distilled Water] for 28 consecutive days. Observations comprised of mortality/morbidity, clinical signs, detailed clinical observation, body weight, body weight gain, feed consumption, ophthalmoscopic examination, functional observational battery/neurobehavioral observation, hematology, clinical biochemistry, urinalysis, gross pathology and histopathology (vehicle control group and high dose group). No treatment related mortality/morbidity were noted in either sex up to 150.0 mg/kg body weight. No treatment related clinical signs were noted up to 150.0 mg/kg body weight in either sex. No abnormalities were detected during ophthalmological examination at 150.0 mg/kg body weight in either sex, when compared with control group. Treatment related mean body weight and body weight gain (percent change in body weight with respect to Day 1) decrease were noted in males at 150.0 mg/kg when compared to concurrent control animals on Day 8, 15, 22 and 28 in all the groups. Moreover statistically (P<0.05) significant decreases in mean body weight were noted in males on Day 22 (up to -14% at 37.5, 75.0 and 150.0 mg/kg) and on Day 15 (-15% at 75.0 mg/kg) when compared to concurrent control animals. Statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted in males on Day 8 (-42% at 150.0 mg/kg), on Day 15 (up to -44% at 37.5, 75.0 and 150.0 mg/kg), on Day 22 (up to -34% at 37.5, 75.0 and 150.0 mg/kg) when compared to concurrent control animals. In recovery males statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted on Day 8 (-60% at 150.0 mg/kg), Day 15 (-32% at 150.0 mg/kg) and on Day 28 (-28% at 150.0 mg/kg) when compared to concurrent recovery control animals. No treatment related changes were noted in feed consumption up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in functional observational battery/ neurobehavioral observation, foot splay, grip strength and motor activity assessment up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in hematological and clinical chemistry parameters up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in urine analysis up to 150.0 mg/kg body weight in either sex. No any abnormalities detected in the oestrus cycle in any of the treatment group at termination. No treatment related gross (external and internal) pathological changes were noted up to 150.0 mg/kg body weight in either sex. No treatment related histopathological examination were noted in any of the tissue/organ at 150.0 mg/kg body weight in either sex. Based on all the above data, and from the observations and conclusion, the NOAEL and LOAEL for the test chemical, Sodium Iodide (CAS No. 7681-82-5) was found to be 75 mg/kg bw/day and 150 mg/kg bw/day, respectively.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

75 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

K1

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Toxicity to reproduction: other studies

Additional information

Data available for the target chemical and supporting data from read across chemicals was reviewed to determine the toxic nature of the test chemical. The studies are as mentioned below:

A 28 days repeated dose toxicity study was performed using the test chemical, Sodium Iodide (CAS No. 7681-82-5). Wistar rats were used as animals of choice, wherein the test chemical was dosed to the rats for 28 days with 14 days recovery period. A total number of 60 Wistar rats (30 males and 30 females) were randomly allocated to six different dose groups of 5 animals/sex/group. The animals allocated to Group G2, G3 and G4/G4-R received 37.5, 75.0and 150.0mg/kg body weight of Sodium Iodide (CAS No.: 7681-82-5) respectively, whereas the animals of Group G1/G1-R, received vehicle alone [Distilled Water] for 28 consecutive days. Observations comprised of mortality/morbidity, clinical signs, detailed clinical observation, body weight, body weight gain, feed consumption, ophthalmoscopic examination, functional observational battery/neurobehavioral observation, hematology, clinical biochemistry, urinalysis, gross pathology and histopathology (vehicle control group and high dose group). No treatment related mortality/morbidity were noted in either sex up to 150.0 mg/kg body weight. No treatment related clinical signs were noted up to 150.0 mg/kg body weight in either sex. No abnormalities were detected during ophthalmological examination at 150.0 mg/kg body weight in either sex, when compared with control group. Treatment related mean body weight and body weight gain (percent change in body weight with respect to Day 1) decrease were noted in males at 150.0 mg/kg when compared to concurrent control animals on Day 8, 15, 22 and 28 in all the groups. Moreover statistically (P<0.05) significant decreases in mean body weight were noted in males on Day 22 (up to -14% at 37.5, 75.0 and 150.0 mg/kg) and on Day 15 (-15% at 75.0 mg/kg) when compared to concurrent control animals. Statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted in males on Day 8 (-42% at 150.0 mg/kg), on Day 15 (up to -44% at 37.5, 75.0 and 150.0 mg/kg), on Day 22 (up to -34% at 37.5, 75.0 and 150.0 mg/kg) when compared to concurrent control animals. In recovery males statistically (P<0.05) significant decrease in percent change in body weight with respect to Day 1 was noted on Day 8 (-60% at 150.0 mg/kg), Day 15 (-32% at 150.0 mg/kg) and on Day 28 (-28% at 150.0 mg/kg) when compared to concurrent recovery control animals. No treatment related changes were noted in feed consumption up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in functional observational battery/ neurobehavioral observation, foot splay, grip strength and motor activity assessment up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in hematological and clinical chemistry parameters up to 150.0 mg/kg body weight in either sex. No treatment related changes were noted in urine analysis up to 150.0 mg/kg body weight in either sex. No any abnormalities detected in the oestrus cycle in any of the treatment group at termination. No treatment related gross (external and internal) pathological changes were noted up to 150.0 mg/kg body weight in either sex. No treatment related histopathological examination were noted in any of the tissue/organ at 150.0 mg/kg body weight in either sex. Based on all the above data, and from the observations and conclusion, the NOAEL and LOAEL for the test chemical, Sodium Iodide (CAS No. 7681-82-5) was found to be 75 mg/kg bw/day and 150 mg/kg bw/day, respectively.

The chemical was given to male and female rats at dietary concentrations of 0 (plain diet), 250, 500 and 1000 ppm. Male rats were treated 14 days before mating and during mating. Female rats were treated 14 days before mating, during mating, during gestation (22 days) and during lactation (21 days). An additional group of female rats treated with plain diet and injected twice with 5-azacytidine at 2 mg/kg (ip) on day 17 of gestation served as positive controls. Parental body weights were recorded at weekly intervals. Food intake was recorded on selected rats during all phases of the experiment. Gestation length was recorded for each pregnant rat giving birth. On the day following birth, all litters were examined for litter size, sex distribution, weight, and number of dead and/or malformed offspring. At this time point, selected male and female rats were subjected to behavioural testing. Male rats treated at 1000 ppm showed reduced body weights and reduced food intake during the pre-mating period. No significant effects were observed on maternal food intake or maternal body weight during gestation. During lactation, the positive control group and the group of female rats treated at 250 ppm showed reduced food intake and reduced body weights. The number of sperm-positive female rats were 22, 27, 30, 26 at 19 at 0 (negative control), 0 (positive control), 250, 500 and 1000 ppm, respectively. No significant effect was observed on the proportion of sperm-positive rats giving birth. The number of female rats with less than 8 live offspring were significantly increased in the positive control group (46% of the dams) and in the group treated at 1000 ppm (64% of the dams) compared to the negative control group (0% affected). Gestation length was unaffected by treatment. The number of pups born per litter was significantly lower in the positive control group (mean, 9.3) and in the group treated at 1000 ppm (mean 9.1) compared to the negative control group (mean 11.5). No significant effects were observed on sex ratio. Offspring mortality was significantly increased from day 0 to 1 in the positive control group (12.3% mortality) and in the group treated at 1000 ppm (6% mortality) compared to the negative control group (0%). Likewise, offspring mortality was significantly increased from day 2-24 in the positive control group (28.6%) and in the group treated at 1000 ppm (21.9%) compared to the negative control group (13.1%). Decreased pre-weaning body weights were observed on days 14 and 21 at ≥500 ppm compared to the negative control group. The positive control group showed the largest weight reductions on day 7, 14 and 21 compared to the negative control group. No significant effects were observed on upper or lower incisor eruption, eye opening, or testicular development. Functionally, the test chemical delayed auditory startle responses at ≥500 ppm, delayed maturation of several aspects of swimming co-ordination at ≥250 ppm, and decreased female running-wheel activity at ≥250 ppm. Other behavioural effects observed lacked dose dependency and were not attributed to the test chemical.NOAELs for systemic toxicity were established at 500 ppm (males) and 1000 ppm (females). NOAEL for reproductive toxicity was established at 500 ppm based on lower number of pups per litter observed at 1000 ppm. NOAEL for developmental toxicity was established at 250 ppm based on behavioural data. Critical effects on developmental were observed at 1000 ppm. Doses of 250, 500 and 1000 ppm corresponded to approx. 22.5, 45 and 90 mg/kg bw/day.

Reproductive toxicity test was performed on Guniea Pigs at a dose range of 300, 1000,2000, 3000,4000, 5000, and 10,000 ppm for a duration of 240 days. Weight losses took place after parturition in several females given higher levels of KN02. These losses were associated with the subacute endometritis and cervicitis. There were no significant alterations in serum nitrite, blood urea nitrogen, or serum potassium in any of the blood samples tested throughout the experiment.The most serious effects on reproduction were seen in females given 5000 or 10,000 ppm of KN02 in drinking water. No live births were recorded at these levels. Reproductive disturbances were manifested in different ways. At 5000 ppm 6 fetuses were aborted, 3 were mummified and 1 was in the process of absorption at the time of necropsy. One female (5000 ppm) died from apparent toxemia. maintained at lower levels of treatment. Fetal losses were 100% in females given 5000 and 10,000 ppm of test chemical. Male fertility was not impaired. Food and water consumption and weight gains were normal except for a diminished rate of gain at 10,000 ppm of KN02. Uterine and cervical inflammatory lesions and degenerative placental lesions were present in females in which the fetuses had been aborted, mummified, or absorbed. The relatively normal reproductive performance by guinea pigs given levels of KNO2 as high as 3000 ppm indicated considerable tolerance (NOEL) and a NOAEL of 4000 ppm by the guinea pig to the test chemical.

Based on the animal data available, the test chemical is non-toxic and observed to be safe for reproductive toxicity. Hence, the test chemical is like to be 'unclassified' as per CLP classification.

Justification for classification or non-classification

Based on the animal data available, the test chemical is non-toxic and observed to be safe for reproductive toxicity. Hence, the test chemical is like to be 'unclassified' as per CLP classification.