Chromium trinitrate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Reference 1

Endpoint:

fertility, other

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-standard study design

Qualifier:

no guideline followed

Deviations:

not applicable

Principles of method if other than guideline:

The effects on fertility were investigated following the administration of chromium (III) chloride to male and female mice for 12 weeks before mating.
Treated males were mated with untreated females; treated females were mated with untreated males. Females were sacrificed one week following
mating.

GLP compliance:

no

Remarks:

Published study

Limit test:

no

Species:

mouse

Strain:

Swiss

Sex:

male/female

Route of administration:

oral: drinking water

Vehicle:

water

Details on mating procedure:

1 treated male: 2 untreated females
1 untreated male: 3 treated females

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Treated males or females were mated with untreated animals following exposure for 12 weeks.

Frequency of treatment:

Continuous.

Details on study schedule:

The effects of chromium chloride on male and female fertility were investigated in sexually mature (7 weeks old) Swiss mice administered this trivalent chromium compound in drinking water. Groups of 9-20 males were administered 0, 2000 or 5000 mg/l chromium chloride for 12 weeks and then mated for ten days, 1 male to 2 untreated females. The exposed males were then removed and 1 week later the females were terminated. Similarly, groups of 11-18 females were administered 0, 2000 or 5000 mg/l chomium chloride for 12 weeks and then mated for ten days, 3 females to 1 untreated male. One week after the removal of the males, the females were terminated. Number of pregnant females, total implantations, viable fetuses and resorptions were recorded. In addition, satellite groups of 10-13 males and 8-10 females administered chomium chloride for 12 weeks were sacrificed at the end of the treatment. Body and reproductive organ weights were recorded in these animals.

Remarks:

Doses / Concentrations:
0, 2000, 5000 mg/l (males)
Basis:
nominal in water
chromium (III) chloride

Remarks:

Doses / Concentrations:
0, 2000, 5000 mg/l (females)
Basis:
nominal in water
chromium (III) chloride

No. of animals per sex per dose:

9-20 males; 11-18 females

Control animals:

yes, concurrent no treatment

Dose descriptor:

LOAEL

Effect level:

2 000 mg/L drinking water

Based on:

element

Remarks:

chromium III

Sex:

male/female

Dose descriptor:

LOAEL

Effect level:

ca. 5 mg/kg bw/day

Based on:

element

Remarks:

chromium III

Sex:

male/female

Reproductive effects observed:

not specified

Exposed males

Bodyweights were significantly reduced by exposure to 2000 and 5000 mg/l chromium chloride, however a dose-response relationship is not apparent. Testes weights were significantly increased in both treated groups of males, however relative weights only are reported and there is no relationship to dose. Relative seminal vesicle weight was significantly lower at 5000 mg/l. Relative preputial gland weight was significantly lower at 2000 and 5000 mg/l, however there is no relationship to dose level.

Fertility was significantly (p<0.005) reduced in males exposed to 5000 mg/l chromium chloride. The number of succesful matings was significantly lower for males exposed to 5000 mg/l. Numbers of implantations and viable foetuses were lower for females mated to males exposed to 2000 and 5000 mg/l. Resportions were increased for females mated to males exposed to 2000 mg/l and the number of dead foetues was increased in females mated to males exposed to 5000 mg/l.

Exposed females

Bodyweights were unaffected by treatment with 2000 or 5000 mg/l. Relative ovary weight was significantly increased and relative uterus weight was significantly decreased in females exposed to 5000 mg/l. Implantation numbers were significantly reduced in females exposed to 2000 and 5000 mg/l; numbers of viable foetuses were also significantly reduced, although there is no relationship to treatment. The numbers of resorptions were increased in both treatment groups.

Parameter		Males exposed			Females exposed
		M			F
		Controls	2000 mg/l	5000 mg/l	Controls	2000 mg/l	5000 mg/l
Bodyweight	(g)	35.7	30.6*	33.4**	34.6	nr	34.2
Testes weight	(mg/10 g bw)	50.72	61.8**	61.2*
Seminal vesicle weight	(mg/10 g bw)	44.5	42.2	35.4**
Preputial gland weight	(mg/10 g bw)	18.7	10.1***	15.0*
Ovary weight	(mg/10 g bw)				2.21	nr	3.63*
Uterus weight	(mg/10 g bw)				23.75	nr	13.90**
Pregnant females	(#, %)	33/40 (82.5%)	18/20 (90%)	8/18 (44%***)	17/18 (94.4%)	10/14 (71.4%)	10/12 (83.3%)
Implantations	(#)	8.18	7.47	7.33	9.00	6.30**	5.70**
Viable foetuses	(#)	8.18	7.33	6.00	8.76	5.55**	5.85**
Resorptions	(#)	0	6	1	4	12	16
Animals with resorptions	(#, %)				2/18 (11%)	4/14 (28%)	4/12 (33%)
Dead foetuses	(#)	0	0	12	0	0	0

Conclusions:

The findings of this study indicate that administration of high levels of water-soluble Cr (III) compounds in the drinking water to male and female mice might have negative effects on fertility. However the US Department of Health and Human Services in its Toxicological Profile for Chromium, September 2012, states that the results should be interpreted with caution due to concerns regarding experimental methods, including decreased water consumption in the higher concentration group (resulting in a potential overestimate of exposure and uncertainty regarding daily dose calculations). Also sperm counts wee not conducted and no standard mating protocol was used.

Executive summary:

Male and female Swiss mice were administered chromium chloride in drinking water for 12 weeks prior to mating with untreated animals. Female mice were sacrificed one week following treatment; the numbers of pregnant animals, total implantations, viable foetuses and resorptions were recorded. Satellite groups of animals were also treated for 12 weeks (without mating) and the weights of the reproductive organs recorded.

There were no deaths or signs of toxicity; slightly reduced bodyweights were seen in both groups of treated males but without any relationship to dose. Relative testes weights were significanlty increased in both satellite groups, however findings may be secondary to bodywieght effects. Relative seminal vesicle and preputial gland weights were significantly lower, however the toxicological significance of these findings is unclear in the absence of histopathology. Relative ovary and uterus weight was increased in females at 5000 mg/l. Mean numbers of implantation sites were lower in treated groups.

Due to some shortcomings in study design, these finding should be interpreted with caution and considering the high doses applied should not become overestimated.

Reference 2

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-standard screening study

Qualifier:

no guideline available

Deviations:

not applicable

Principles of method if other than guideline:

Effects on sperm parameters measured during a 90-day inhalation study.

GLP compliance:

not specified

Species:

rat

Strain:

other: CDF

Sex:

male/female

Route of administration:

inhalation: dust

Type of inhalation exposure (if applicable):

nose only

Vehicle:

unchanged (no vehicle)

Details on mating procedure:

Not applicable

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

6 hours/day

Frequency of treatment:

5 days/week

Remarks:

Doses / Concentrations:
17, 54, 168 mg/m3
Basis:
analytical conc.

No. of animals per sex per dose:

15

Control animals:

yes, concurrent no treatment

Sperm parameters (parental animals):

In a 13-week nose-only inhalation study of chromic oxide dust, sperm samples from male rats were collected at necropsy and were used for automated evaluation of sperm motility, count and morphology.

Dose descriptor:

NOAEL

Effect level:

ca. 30 mg/m³ air (nominal)

Based on:

element

Remarks:

chromium III

Sex:

male/female

Basis for effect level:

other: No effects were seen at the highest dose tested (168 mg/m3 chromium (III) hydroxide sulphate, equivalent to 30 mg/m3 Cr(III)

Reproductive effects observed:

not specified

No compound-related effects were noted for sperm motility or morphology in rats with nose-only exposures to chromium hydroxide sulphate dust at 17, 54, or 168 mg/m3 for 6 h/day, 5 days/week for 13 weeks. Ovary and testes weights were also unaffected by treatment.

Conclusions:

Inhalation exposure to chromium oxide dust in this study did not have any adverse effects on sperm parameters.

Executive summary:

Sperm parameters were assessed in male rats exposed by inhalation to chromium (III) oxide dusts in a 90-day study at concentrations of 0, 17, 54 or 168 mg/m3. No treatment-related effects on fertility parameters were apparent.

Effect on fertility: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

23 mg/kg bw/day

Study duration:

subchronic

Species:

mouse

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

137.3 mg/m³

Study duration:

subchronic

Species:

rat

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Screening study with basic chromium sulphate

A 90-day inhalation study with basic chromium sulphate (Derelanko et al, 1999) showed no effects on sperm parameters at exposure concentrations of up to 168 mg/m3. A number of drinking water studies using chromium chloride have suggested effects on male and/or female reproductive performance at high dose levels, however reviews have identified a number of deficiencies in these studies and the effects on the reproductive system are unclear.

Studies with chromium (III) chloride

Administration of high dose levels of chromium chloride in the drinking water (Elbetieha & Al-Hamood, 1997) to mice indicate adverse effects on male and female fertility. The same authors also report effects on fertility and sexual behaviour in male rats.

Screening studies performed with chromium (III) compounds

No effects on male fertility, female fertility or embryofoetal development were seen in rats mated following exposure to dietary levels of up to 5% chromium (III) oxide for 60 days (Ivankovic & Preussmann, 1975), equivalent to mean achieved intakes in excess of 2000 mg/kg bw/d. No effects on testes or ovary weights were seen following administration at this dose level for 2 years. No effects on sperm parameters were seen in male rats exposed by inhalation to chromium oxide dust at concentrations of up to 30 mg/m3 in a 90-day study (Derelanko et al, 1999). The available information therefore do not indicate any adverse effect of chromium (III) oxide administration on either the reproductive organs or on reproductive function. Kinetic data show that this Cr(III) is poorly absorbed. Chromium (III) is an essential element and highly water-soluble forms (such as the picolinate complex) are used as dietary supplements; data indicate that chromium (III) supplementation may be of benefit in controlling insulin-dependent diabetes and it has been suggested that chromium (III) supplements may be of benefit in the control of gestational diabetes. Based on the results of the screening studies, the very low systemic availability of chromium (III) oxide and the essentiality of chromium, it is not proposed to perform any additional studies of reproductive toxicity. The performance of a two-generation reproductive toxicity study is not justified for scientific reasons or on animal welfare grounds.

Other literature studies

Studies are available for other chromium (III) salts. These studies are of limited value due to methodological deficiencies and/or the relevance of the route of administration, however they are summarised here for completeness. The following summary and conclusion is taken from the 2006 FIOH review:

Summary of reproductive toxicity studies reviewed by the FIOH (ICDA, 2006)

No guideline-based reproductive toxicity studies were found for any trivalent chromium compound and there are only a few other studies of the reproductive toxicity of trivalent chromium compounds. No studies of the effects of metallic chromium on fertility are available but it can be assumed that the reproductive toxicity of metallic chromium resembles that of chromium(III) oxide. In the case of water-insoluble chromium(III) oxide no compound-related effects on sperm parameters or testicular and ovarian weights were seen after inhalation exposure of rats to chromium(III) oxide 6 hours per day 5 days per week over 13 consecutive weeks at the concentration levels of 3, 10 or 30 mg Cr3+/m3 (Derelanko et al, 1999). Also, the study by Ivankovic & Preussmann (1975) did not show any adverse effects on the reproductive performance of rats treated orally with very high doses of chromium(III) oxide. Based on these studies and the toxicokinetic knowledge of the poor bioavailability of water-insoluble chromium(III) oxide it is concluded that chromium(III) oxide does not cause a hazard for fertility. Although one old rabbit study (Behari et al, 1978) with chromium nitrate claims that intraperitoneally administered water-soluble trivalent chromium compounds may cause even more marked testicular effects than hexavalent chromium, this is not supported by another study performed with i.p. administration of chromium chloride (Ernst, 1990). In addition, because i.p. injection can lead to unrealistically high testicular chromium levels due to the direct uptake of chromium into the peritoneal organs (Sipowicz et al, 1997) studies using inhalation exposure or oral administration are considered more relevant for the assessment of reproductive risks of trivalent chromium. There are four oral studies with water-soluble trivalent chromium compounds suggesting effects on male and/or female reproductive performance (Zahid et al, 1990; Elbetieha & Al Hamood 1997; Bataineh et al, 1997; Al Hamood, Elbetieha et al, 1998). The study by Zahid et al suggests effects on spermatogenesis at dose levels of 3 mg Cr3 +/kg/day. However, this study suffers from serious deficiencies and from the obscurity concerning the identity and the purity of the test substance. In other oral (drinking water) studies, effects on reproductive performance were seen in mice and rats at dose levels ≥24 mg/kg/day of Cr3+as chromium chloride hexahydrate. However, due to deficiencies in study designs and execution it is not possible to conclude whether these effects were real, specific effects on the reproductive system or not. On the other hand, the possibility of adverse reproductive effects caused by highly excessive trivalent chromium intake cannot to be totally excluded. According to toxicokinetic studies, chromium can reach the testis and is found mainly in the interstitial compartment of the testis. The interstitial compartment of testis contains testosterone-producing Leydig cells. Since trivalent chromium is an essential nutrient involved in cellular glucose and lipid metabolism, it is possible that the excessive uptake of trivalent chromium into the interstitial compartment perturbs the chromium balance of Leydig cells and results in changes in testosterone production as suggested by Al-Hamood et al, and Elbetieha & Al-Hamood 1997. Nevertheless, according to the 13-week inhalation toxicity study by Derelanko et al, no compound-related effects on sperm parameters, testicular or ovarian weights were seen after exposure of rats to basic chromium sulphate 6 hours per day at concentration levels of 3,10 and 30 mg/m3 of Cr3+(corresponding to inhaled doses of 0.7-6.6 mg Cr3+/kg/day). This study suggests that trivalent chromium does not cause effects on fertility at dose levels up to 6.6 mg Cr3+/kg/ day. 6.6 mg Cr3+/kg/day (30 mg Cr3+/m3) is selected as a NOAEL for fertility effects. 24 mg Cr3+/kg/day is selected to represent a LOAEL for reproductive toxicity. This is based on the effects on reproductive organ weights and sexual behaviour seen in the study by Bataineh and co-workers (Bataineh et al, 1997). However, it should be noted that at the same dose level, a clear reduction in the bodyweight gain of treated animals was also seen and therefore it is unclear whether the observed effects were real and specific to the reproductive system or not.

There is therefore considered to be no firm evidence for an effect of Cr3+ on fertility at dose levels not causing systemic toxicity. Further testing for reproductive toxicity is not proposed.

Short description of key information:
LOAEL (oral, mouse): approx. 5 mg chromium (III)/kg bw/day equivalent to approx. 23 mg/kg bw/d chromium trinitrate
NOAEC (rat, inhal.): 137.3 mg/m3 as chromium trinitrate (high dose group with no effects on reproductive organs in this study)

Effects on developmental toxicity

Description of key information

No evidence of foetotoxicity, developmental toxicity or teratogenicity was seen in mice exposed to water-soluble complexes of Cr(III) delivering estimated daily doses of Cr(III) equivalent to 25 mg/kg bw/d (picolinate group), 3.3 mg/kg bw/d (low dose Cr3 group) and 26 mg/kg bw.d (high dose Cr3 group).  This equates to 119 mg/kg bw/d calculated as chromium trinitrate as NOAEL.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline comparable, published study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Principles of method if other than guideline:

Method broadly comparable to OECD 414, performed in the mouse using dietary administration

GLP compliance:

no

Remarks:

: published study

Limit test:

no

Species:

mouse

Strain:

CD-1

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Male and female CD-1 mice, obtained from Charles River Breeding Laboratories, International (Wilmington, MA) were housed in an AAALAC-approved animal facility in rooms maintained at 22721C, with 40–60% humidity and a 12-hr photoperiod. Animals were bred naturally, two females with one male. Observation of a copulation plug was designated GD 0. Mated females were individually housed in shoe-box-type cages with hardwood bedding and were given Harlan-Teklad LM-485 rodent diet and tap water ad libitum.

Duration of treatment / exposure:

Females were exposed from Gestation Day 6-17

Frequency of treatment:

Continuous (dietary)

Duration of test:

Maternal animals were sacrificed on Gestation Day 17.

Remarks:

Doses / Concentrations:
Control
Basis:
other: untreated diet

Remarks:

Doses / Concentrations:
200 mg/kg bw/d chromium picolinate
Basis:
other: based on predicted food consumption

Remarks:

Doses / Concentrations:
15 mg/kg bw/d Cr3
Basis:
other: based on predicted food consumption

Remarks:

Doses / Concentrations:
120 mg/kg bw/d Cr3
Basis:
other: based on predicted food consumption

No. of animals per sex per dose:

Not stated, however the numbers of litters in each group range from 24-29

Control animals:

yes, plain diet

Details on maternal toxic effects:

Maternal toxic effects:no effects

Dose descriptor:

NOAEL

Effect level:

26 mg/kg bw/day (nominal)

Based on:

element

Remarks:

chromium III

Basis for effect level:

other: maternal toxicity

Dose descriptor:

NOAEL

Effect level:

26 mg/kg bw/day (nominal)

Based on:

element

Remarks:

chromium III

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Abnormalities:

not specified

Developmental effects observed:

not specified

No signs of maternal toxicity were observed.

Mean foetal weights, foetal viability and the proportion of resorptions were unaffected by treatment. No gross malformations were observed in any of the foetuses. The number of implantations in the low dose Cr3 group was lower than the other treated groups, however this is not considered to be an effect of treatment in the absence of a dose-response relationship and because implantation occurred prior to exposure. No effects of treatment were observed on the incidence of skeletal anomalies. The authors note that a previous study (Bailey et al, 2006) reported an increased incidence of cervical arch defects in the offspring of mice exposed to chromium picolinate, however the incidence of defects in that study (6.26%) is very similar to the control incidence in this study (5.79% and is therefore not considered to be related to treatment.

Summary of findings

Parameter		Dose group
		0	Cr picolinate	Cr3 (low)	Cr3 (high)
Litters	(#)	27	29	26	24
Foetuses	(#)	332	369	275	342
Litter size	(#)	12.30	12.72	10.58	14.25
Foetal weight	(g)	1.02	1.05	1.08	1.02
Implantations	(#)	12.64	13.18	11.00	13.79
Dead/resorbed foetuses	(#)	2.74	3.29	3.48	1.29
Cervical arch defects	(#)	4.65	6.26	5.18	3.98

Cervical arch defects refer to a distal split in the first or second cervical vertebral arch

Conclusions:

No evidence of foetotoxicity, developmental toxicity or teratogenicity was seen in mice exposed to water-soluble complexes of Cr(III) delivering estimated daily doses of Cr(III) equivalent to 25 mg/kg bw/d (picolinate group), 3.3 mg/kg bw/d (low dose Cr3 group) and 26 mg/kg bw.d (high dose Cr3 group).

Executive summary:

Mated female mice were administered Cr(III) in the diet from Days 6 -17 of gestation. Dams were sacrificed on Day 17 and the uterine contents investigated. Foetuses were assessed for external defects and skeletal findings following double staining. No maternal toxicity was observed. No evidence of teratogenicity, foetotoxicity or developmental toxicity was seen. The results of this study also show that a reported increased incidence of cervical arch defects in a previous study by the same authors was within the background range.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

119 mg/kg bw/day

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Embryo/foetolethality and teratogenicity have been reported in studies with water-soluble chromium chloride in non-standard studies using high-dose parenteral (ip or sc) administration. Toxicokinetic data shows that trivalent chromium accumulates in the placenta but only a low proportion of chromium in maternal serum crosses the placenta to the foetus (FIOH, 2006). The results of an EST assay performed with the water-soluble chromium (III) chloride salt were negative. A guideline-comparable study of Cr (III) toxicity in the mouse (Bailey et al, 2008) performed with two water-soluble Cr (III) complexes do not indicate any teratogenicity, foetotoxicity or developmental toxicity.

Justification for classification or non-classification

The available information indicates a possible effect of Cr (III) on male and female fertility only at high dose levels associated with systemic toxicity. There is no evidence of developmental toxicity. No classification is proposed for reproductive or developmental toxicity according to CLP (Regulation EC No 1272/2008) or DSD (Directive 67/548/EEC).