Annex A

Author and year

Study details

Dose level

Findings

No observed adverse effect level (NOAEL)

Comments on the NOAEL

Poon et al. (1998)

Species: Sprague-Dawley rats.

Route of exposure: Oral-Drinking water.

Initial study duration: 13 weeks.

Initial No/Sex: 15 male and 15 female.

Follow up study duration: 13 weeks followed by a 4-week recovery period.

Follow up No/Sex: 10 male and 10 female.

Initial Study Original Dose: 0, 0.5, 5, 50, or 500 ppm antimony potassium tartrate.

Initial Study Recalculated Dose Levels: 0, 60, 560, 5,580 and 42,170 μg/kg bw/day in males and 0, 60, 640, 6,130 and 45,690 μg/kg bw/day in females.

Follow up Study Original Dose: 0 or 500 ppm.

Dose-dependent decrease in serum glucose levels in females at ≥640 μg Sb/kg bw/day. Decrease also noted in males but not statistically significant.

decrease in water and food consumption, a decrease in body weight gain (significant in males starting at week 6 and females at week 12), haematological changes which differed between males and females, decreases in serum creatinine levels and alkaline phosphatase levels, and liver effects including changes to liver enzyme activity all observed at the highest antimony dose (42,170/45,690 μg Sb/kg bw/day in males and females respectively).

Dose-related increase in the severity of anisokaryosis observed in all antimony-exposed groups.

Increased hepatocellular portal density in all antimony-exposed groups and minimal nuclear hyperchromicity at ≥560/640 μg Sb/kg.

increased myeloid hyperplasia in the bone marrow was observed at ≥5,580 μg Sb/kg bw/day in males and ≥640 μg Sb/kg bw/day in females.

Sinus congestion at ≥640 μg Sb/kg bw/day observed in females. Sinus congestion at ≥560 μg Sb/kg bw/day and sinus hyperplasia and arterial cuff atrophy at 42,170 μg Sb/kg bw/day observed in males.

In the recovery period, increases in incidence of sinus congestion (males only), arterial cuff atrophy, periarteriolar lymphocyte sheath cell density and sinus haematopoiesis were observed.

Poon et al. (1998) recommended NOAEL: 60 μg Sb/kg bw/day.

Lynch et al. (1999) recommended NOAEL: 6,000 Sb μg/kg bw/day.

Poon et al. (1998) recommended NOAEL: NOAEL is based on decreased in serum glucose levels in females at ≥640 μg Sb/kg bw/day. However, the Committee determined that these effects showed limited dose-response. The Committee noted that an NTP intraperitoneal study did not observe these effects despite higher concentrations and greater bioavailability of antimony.

Lynch et al. (1999) recommended NOAEL: NOAEL is based on decreased body weight gain and decreased food and water consumption at the 500 ppm dose level. The COT agrees that this is an appropriate NOAEL for this study and is the appropriate point of departure to use as the basis of a HBGV for antimony.

Marmo et al. (1987)

Species: NOS Albino normotensive rats.

Route of exposure: Oral-Drinking water.

Study duration: Maternal exposure: - 1st day of pregnancy until weaning (22nd day after delivery) or from PND1 to PND 22.

Pups: - From weaning until 30 or 60 days of age.

No/Sex: 30 per group.

Rat offspring: - 10 pups/ group, equal sex ratio.

Original Dose: 1 and 10 mg/L antimony trichloride.

Recalculated Dose Levels: 70 and 700 µg Sb/kg bw/day.

Prenatal and Postnatal exposure: Decreased antihypotensive response to norepinephrine and hypotensive response to isoprenaline at both dose levels in 60-day old rats. The hypotensive response to acetylcholine was decreased at the highest dose of antimony trichloride in 60-day old rats.

No change in antihypotensive or hypotensive responses was seen in 30-day old rats.

Postnatal exposure: - 60-day-old offspring in the high-dose group showed reduced antihypotensive      responses to carotid artery occlusion and norepinephrine injection, as well as reduced hypotensive responses to isoprenaline and acetylcholine.

In 30-day-old offspring in the high-dose group, reduced hypotensive responses to isoprenaline and acetylcholine were also observed.

In the low-dose group, 60-day-old rats had reduced responses to norepinephrine and isoprenaline, while 30-day-old rats showed responses similar to controls.

70 μg Sb/kg bw/day.

Pup LOAEL: 700 μg Sb/kg bw/day.

See Rossi et al. (1987)

Rossi et al. (1987)

Species: NOS Albino normotensive rats.

Route of exposure: Oral-Drinking water.

Study duration: Prenatal: 1st day of pregnancy until weaning (22nd day after delivery).

Postnatal: 22nd to 60 days in drinking water.

No/Sex: 30 per group.

Rat offspring: - 10 pups/ group, equal sex ratio.

Original Dose: 1 and 10 mg/L antimony trichloride.

Recalculated Dose Levels: 70 and 700 µg Sb/kg bw/day.

Both doses: Maternal body weight decreased significantly in a dose-dependent manner by the 20th day of gestation.

High dose: Pups had decreased BW; No macroscopic teratogenic effects have been observed.

Antimony exposure did not significantly affect maternal and pup systolic arterial blood pressure, length of gestation, and number of newborns per litter.

Maternal NOAEL: 70 μg Sb/kg bw/day.

Pup LOAEL: 700 μg Sb/kg bw/day

NOAEL is based on dose-dependent decrease in maternal body weight by gestation day 20 following prenatal oral antimony exposure. The COT noted that the baseline maternal body weight in the study by Rossi et al. (1987) at gestation day 0 was approximately 7% lower in treated groups compared to controls. Consequently, the observed 8–10% reduction in maternal body weight at gestation day 20 used as the basis for the maternal NOAEL was considered a relatively small change, given the pre-existing baseline differences. With the lower maternal body weights in the treated groups reported in the Rossi et al. (1987) study, it was suggested that the observed lower pup body weight could be secondary to the lower maternal body weights seen in this group rather than direct effect of antimony on pups. The Committee also noted that the NTP intraperitoneal study observed body weight effects only at the highest dose (9,600 µg Sb/kg bw/day). For these reasons, the lower NOAEL and LOAEL relating to maternal and pup body weight reported in the Rossi et al. (1987) study were discounted.

Angrisani et al. (1987)

Species: NOS Albino normotensive rats.

Route of exposure: Oral-Drinking water.

Study duration: Postnatal: From PND1 to PND60.

No/Sex: 30 per group

Rat offspring: - 10 pups/ group, equal sex ratio.

Original Dose: 1 and 10 mg/L antimony trichloride.

Recalculated Dose Levels: 70 and 700 µg Sb/kg bw/day

Postnatal exposure to antimony trichloride did not affect maternal or pup body weights or systolic arterial blood pressure.

No macroscopic teratogenic effects have been observed.

Antimony exposure did not significantly affect the length of gestation, and number of newborns per litter.

Maternal NOAEL: 70 μg Sb/kg bw/day.

Pup LOAEL: 700 μg Sb/kg bw/day.

See Rossi et al. (1987)

Kanisawa and Schroeder (1969)

Species: Mice (White Swiss, Charles River CD-1).

Route of exposure: Oral-Drinking water.

Study duration: Lifetime exposure.

No/Sex: Control mice – 71; Antimony treatment – 76.

Original Dose: 5 ppm Antimony Potassium Tartrate.

Recalculated Dose Level:

350 µg Sb/kg bw/day.

Compared to control, significant differences in the incidences of spontaneous tumors and malignant tumors did not appear.

Female mice had shorter life spans when given antimony than their controls.

Fatty degeneration of liver noticed in both control (22.2%) and antimony fed groups (15.9 %).

350 μg Sb/kg bw/day.

The COT raised concerns regarding the reliability of the data and challenges interpreting the data. Furthermore, the nature of this study does not allow for the demonstration of a dose-response, therefore the NOAEL was discounted.

Schroeder et al. (1970)

Species: Long Evan Rats.

Route of exposure: Oral-Drinking water.

Study duration: 2 years.

No/Sex: Not reported.

Original Dose: 5 ppm - Antimony Potassium Tartrate (APT).

Recalculated Dose Level: 430 µg Sb/kg bw/day.

Negligible effects on growth and mature weight. Antimony was not tumorigenic.

Decrease in survival rate. Antimony, however, was innately toxic, males surviving 106 days and females 107 days less than the controls at median life spans, and 70 and 165 days less when 90% were dead; Hearts of males fed antimony weighed 18.9% less than their respective controls, whereas the hearts of females weighed 3.5% more.

Decreased non-fasting serum glucose levels. Non fasting glucose levels were lower than fasting ones in the antimony group. Glycosuria was found in 23% of 90 controls, 43% of 23 in the antimony group.

In both sexes, significant differences in the serum cholesterol levels occurred when compared to their controls. Antimony was found to accumulate in various tissues like kidney, liver, heart, lung and spleen, with significant increases in concentration over time.

LOAEL: 430 μg Sb/kg bw/day.

The COT raised concerns regarding the reliability of the data and challenges interpreting the data. Furthermore, the nature of this study does not allow for the demonstration of a dose-response, therefore the LOAEL was discounted.

NTP (1992)

Species: B6C3F1 Mice

Route of exposure: Intraperitoneal injection.

Study duration: 13 weeks.

No/Sex: 10 Males per group.

10 Females per group.

Original Dose: 0, 1.5, 3, 6, 12 and 24 mg/kg antimony potassium tartrate; 3 times per week.

Recalculated Dose Levels: 0, 600, 1,200, 2,400, 4,800 and 9,600 µg Sb/kg bw/day.

High dose:  Body weights were reduced by about 10% compared to controls (not statistically significant).

Hematological analyses revealed decreases in red blood cell counts and hemoglobin of both sexes of high-dose mice at week 7 and again at week 13 for the red blood cell counts.

In association with these changes was increased absolute and relative spleen weight.

4,800 μg Sb/kg bw/day.

The dose was given intraperitoneally therefore this study was not used for the determination of the appropriate NOAEL for oral antimony consumption.

NTP (1992)

Species: F344/N rats.

Route of exposure: Intraperitoneal injection.

Study duration: 13 weeks.

No/Sex:

10 Males per group.

10 Females per group.

Original Dose: 0, 1.5, 3, 6, 12 and 24 mg/kg antimony potassium tartrate; 3 times per week.

Recalculated Dose Levels: 0, 600, 1,200, 2,400, 4,800 and 9,600 µg Sb/kg bw/day.

Mortality was observed in 4 of 10 male rats in the highest dose groups.

A reduction in body weight was seen in both male (18%) and female (11%) rats from these groups.

Relative liver weight was increased in male and female rats from all dose groups (maximum increase of 20% for males and 40% for females at 9600 µg Sb/kg bw/day).

Dose-related increases in serum alanine aminotransferase and sorbitol dehydrogenase were also observed in male and female rats.

Hepatocellular degeneration and necrosis were observed in male rats and in female rats. Kidney degeneration was also observed in the highest dose group in female rats (3/10).

1,200 μg Sb/kg bw/day.

The dose was given intraperitoneally therefore this study was not used for the determination of the appropriate NOAEL for oral antimony consumption.

Sunagawa (1981)

Species: Wistar rats.

Route of exposure: Oral-Feeding.

Study duration: 24 weeks.

No/Sex: 5 per dose.

Original Dose: Metallic Antimony: 0, 0.5, 1.0, 2.0%.

Antimony Trioxide: 0, 1.0, 2.0%.

Recalculated Dose Levels: Metallic Antimony: 0, 500,000, 1,000,000, 2,000,000 µg Sb/kg bw/day.

Antimony Trioxide: 0, 418,000, 836,000 µg Sb/kg bw/day.

Metallic antimony high dose: decreased body weight gain.

Metallic antimony high dose: decreased hematocrit and hemoglobin.

Antimony trioxide all dose: decreased erythrocyte levels.

Metallic antimony mid and high dose: slight cloudy swelling in hepatic cords.

Antimony trioxide all dose: slight cloudy swelling in hepatic cords.

LOAEL: 418,000 μg Sb/kg bw/day.

The LOAEL is higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.

Hiraoka (1986)

Species: Wistar rats.

Route of exposure: Oral-Feeding.

Study duration: 12 weeks.

12 weeks recovery.

No/Sex: 12 males per group.

Original Dose: Metallic Antimony: 0.1% (w/w), 1.0% (w/w) o.

Antimony Trioxide: 1.0% (w/w).

Recalculated Dose Levels: Metallic Antimony: 85,000, 850,000 µg Sb/kg bw/day.

Antimony Trioxide: 700,000 µg Sb/kg bw/day.

BW gain decreased for all.

The weight of the rats of each 1.0%-Sb and 1.0%-Sb2O3 groups was lighter than that of 0.1%-Sb group.

Recovery animal- increased in weight up to the normal level. Some significant changes of the organ weight and the ratio between organ weight and body weight of the rats, after the administration of Sb and Sb2O3; 1.0%-Sb: decreased haemtocrit.

0.1%-Sb: no changes in Hb, AST and albumin to globulin ratio. 0.1%-Sb: increased ALT.

1.0%-Sb: decreased total protein levels; High concentrations of antimony were found in liver, spleen, lungs, hairs and bone and the highest concentration was detected in the blood of the rats.

700,000 μg Sb/kg bw/day.

The NOAEL is higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.

Miranda et al. (2006)

Species: Wistar rats.

Route of exposure: Subcutaneous injection.

Study duration:  GD1 – 20.

No/Sex: 19-21/group.

Original Dose: 0, 75, 150, 300 mg SbV/kg bw/day Meglumine antimoniate.

Recalculated Dose Levels: 0, 75,000, 150,000 or 300,000 µg Sb/kg/day.

Maternal and fetal body weights were reduced in the high-dose group (18% and 10%, respectively, at 300,000 µg Sb/kg/day).

Embryo lethality was also observed in this dose group (decreased number of live fetuses).

The frequency of dilated ureter was increased in fetuses from the 150,000 and 300,000 µg Sb/kg/day dose groups.

Skeletal variations were also seen in the mid- and high-dose groups (misaligned sternebrae, supernumerary ribs, misshapened basiooccipital bone).

Transplacental transfer of antimony was confirmed by fetal blood analysis with fetal blood concentrations measured to be roughly one-third of the concentrations found in maternal blood.

75,000 µg Sb/kg/day.

The LOAEL is higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.

Hext et al. (1999)

Species: Wistar rats.

Route of exposure: Oral-Feeding.

Study duration: 90 days.

No/Sex: 12 Males per group.

12 Females per group.

Original Dose: 0, 1,000, 5,000, 20,000 ppm antimony trioxide.

Recalculated Dose Levels: Males: 0, 70,000, 353,000, 1,408,000 µg Sb/kg bw/day.

Females: 0, 81,000, 413,000, 1,570,000 µg Sb/kg bw/day.

Absolute and relative liver weights were increased by approximately 10% in female rats fed 20,000 ppm antimony trioxide; Elevated red cell count in high-dose male rats (+4%) and a decreased mean cell volume in high-dose female rats (-2%); Triglyceride content was increased (+30%) and alkaline phosphatase activity was decreased (-12%) in high-dose male rats. High-dose female rats exhibited an increase in plasma cholesterol (+13%), a decrease in alkaline phosphatase activity (-36%) and an increase in aspartate aminotransferase activity (+52%). Alkaline phosphatase activity was also decreased (-23%) in female rats given 5,000 ppm of antimony trioxide in the diet.

In high-dose female rats, urine volume was increased (+79%) and specific gravity was decreased (-1%). Urinary pH was increased in male rats given 1,000 ppm (+5%) or 20,000 ppm (+5%) but was similar to the control value in the 5,000-ppm group. Changes in urinary parameters were not dose-related and were considered by the study authors to be incidental.

1,408,000 µg Sb/kg bw/day (male rats) and 1,570,000 µg Sb/kg bw/day (female rats).

The NOAELs are higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.

Coelho et al. (2014)

Species: Pregnant female Wistar rats.

Route of exposure: Subcutaneous injection.

Study duration: Gestation Day 0-PND 21.

No/Sex: Control - 14; Treatment - 16 per dose.

Original Dose: 0, 75, 150, 300 mg SbV/kg bw/day of meglumine antimoniate.

Recalculated Dose Levels: 0, 75,000, 150,000, 300,000 µg SbV/kg bw/day.

At the highest dose, MA reduced the birth weight and the number of viable newborns.

In the male offspring, MA did not impair development (somatic, reflex maturation, weight gain, puberty onset, open field test), sperm count, or reproductive performance.

Except for a minor effect on body weight gain and vertical exploration in the open field, MA also did not affect the development of female offspring.

Measurements of the Sb levels in the blood of MA-treated female rats and their offspring demonstrated that Sb is transferred to the fetuses via the placenta and to the suckling pups via milk.

150,000 µg SbV/kg bw/day.

The dose was given via subcutaneous injection therefore this study was not used for the determination of the appropriate NOAEL for oral antimony consumption.

Alkhawajah et al. (1995)

Species: Sprague Dawley rats.

Route of exposure: Intramuscular injection.

Study duration:  Gestation Day 6-15.

No/Sex: 10 per dose.

Original Dose Levels:

1. Sodium Stibogluconate (SSG): 30,000, 100,000, 300,000, 900,000 µg Sb/kg bw/day.

2. Meglumine Antimoniate (MA): 30,000, 100,000, 300,000, 900,000 µg Sb/kg bw/day.

3. Antimony Trichloride (SbCl3): 100,000 µg Sb/kg bw/da.y

Reduction (P<0.05) in foetal birth weight and litter size was observed as compared to the control.

High dose of SSG & MA: - Death of all animals before completion of the treatment; Skeletal anomalies were restricted to the formation of a rudimentary 14th rib.

Haematoma was only seen in the extremities of foetuses born to antimony treated animals.

Treatment of pregnant rats with SSG (30,000 µg Sb/kg) daily for 10 successive days, starting on day 6 of gestation, exhibited a 5.9% foetal resorption rate. This effect seems to be dose dependent as doses of 100,000 and 300,000 µg Sb/kg caused 14% and 21.4% foetal resorption, respectively.

Injection of MA at the same dose levels of 30,000, 100,000 and 300,000 µg Sb/kg also caused dose dependent increase in foetal resorption rates of 1.2%, 26.7% and 33%, respectively. It was also observed that antimony trichloride caused 36% foetal resorption when it was injected at a dose of 100000 µg/kg.; Visceral anomalies observed in the antimony-treated animals consisted of platal, ocular (undeveloped eyes) and asymmetrical brain hemispheres.

All tissues that were analysed (placenta and tissue of dead foetuses) in this study contained antimony in concentrations ranging from 53.4±0.2 to 1.61±0.1 µg Sb/g and the effects were dose dependent.

-

The dose was given via intramuscular injection therefore this study was not used for the determination of the appropriate NOAEL for oral antimony consumption.

Omura et al. (2002)

Species: Wistar rats, CD-1 mice.

Route of exposure: Oral-gavage feeding.

Study duration: 4 weeks.

No/Sex: Rats: 7 to 8 per group.

Mice: 8-10 per group.

Original dose:

1.Antimony Potassium Tartrate group: 27.4 mg/kg body weight.

2.Low-Antimony trioxide group: 12 mg/kg body weight

3.High-Antimony trioxide group: 1,200 mg/kg body weight.

Recalculated dose levels:

1.Antimony Potassium Tartrate group: 10,000 µg Sb/kg bw/day.

2.Low-Antimony trioxide group: 10,000 µg Sb/kg bw/day.

3. High-Antimony trioxide group: 1,000,000 µg Sb/kg bw/day.

1. Three mice (1 control, 2 given 1,200,000 µg/kg-day) died due to gavage error; Sperm parameters were not affected by neither compounds and histopathology results were essentially negative.

1,000,000 µg Sb/kg bw/day.

The NOAEL is higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.

Belyaeva (1967)

Species: Rats (not specified).

Route of exposure: Inhalation.

Study duration: 1.5-2 months, 4 hours/day.

No/Sex: 10-24/group.

Original Dose: 0 and 209,000 µg Sb/m³ antimony trioxide.

Recalculated Dose Levels: 0 and 209,000 µg Sb/m³.

No changes in body weight gain were noted. Fetal body weights remained unchanged.

Unspecified lesions were reported in the lungs, liver, kidneys, and pancreas.

Reproductive effects, including failure to conceive and uterine metaplasia, were observed. However, a decrease in fertility and reduced number of offspring was found in rats exposed to 209 mg Sb/m³ of antimony trioxide before conception and during gestation.

209,000 µg Sb/m^3.

The dose was given via inhalation therefore this study was not used for the determination of the appropriate NOAEL for oral antimony consumption.

REACH registration dossier submitted to ECHA (2014)

Species: Sprague- Dawley rats.

Route of exposure: Oral-Drinking water.

Study duration: Gestation days 6-19.

No/Sex: 2 females per dose.

Original Dose: 0, 100, 300 and 1000 mg/kg bw/day sodium hexahydroxo-antimonate.

Recalculated Dose Levels:   0, 49,000, 148,000, 493,000 µg Sb/kg bw/day.

Increased (non-significant) incidence in delayed skeletal development were observed in the mid and high dose groups.

When considering skeletal malformations overall, incidence was observed in 99.3% to 100% of fetuses and 100% of litters including controls.

49,000 µg Sb/kg bw per day.

The NOAEL is higher than the NOAEL from Poon et al. (1998) that the COT determined was the appropriate point of departure to use as the basis of a HBGV for antimony.