Hydrocarbons, C10-C13, aromatics, >1% naphthalene

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

There is no substance specific data available forHydrocarbons, C10-C13, aromatics, >1% naphthalene. However, data is available for structural analogue, C9 aromatics and presented in the dossier. This data is read across toHydrocarbons, C10-C13, aromatics, >1% naphthalene based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

C9 Aromatic hydrocarbons (three-generation reproductive toxicity):

NOAEC >=1500 ppm mg/kg bw/day for males and female rats.

Additionally, in order to comply with standard information requirements for Annex X substances, OECD 443 tests are proposed for structural analogues, Hydrocarbons, C9-C10, aromatics >1% Naphthalene (EC# 946-365-8) and Hydrocarbons C11-C15 Aromatics <1% Naphthalene (EC# 922-153-0). This read across is based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in Section 13.2 of the dossier. This endpoint will be updated subsequent to ECHA's approval of the testing proposal and availability of data upon completion of the study.

Link to relevant study records

Reference

Reference 1

Endpoint:

three-generation reproductive toxicity

Type of information:

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

Adequacy of study:

key study

Study period:

1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Source of data is from peer reviewed literature. Acceptable well-documented study report which meets basic scientific principles. GLP.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: Similar to OECD TG 416 (Two-Generation)

Deviations:

yes

Remarks:

3 generation study

Principles of method if other than guideline:

A three generational study examining reproductive toxicity.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Portage, MI
- Age at study initiation:(P) 6 x wks; (F1) 5-7 x wks; (F2) 22 days
- Housing: Inidividually housed in wire mesh cages
- Diet (e.g. ad libitum): Purina Certified Rodent Chow No. 5002 ad libitum except during exposure
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 2-3 weeks

ENVIRONMENTAL CONDITIONS
Animal husbandry followed standards by the US Department of Health, Education, and Welfare (1985)

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

unchanged (no vehicle)

Details on exposure:

- Exposure apparatus: 16 m glass and steel chambers.
- Method of holding animals in test chamber: cages
- Source and rate of air: Air was provided by a seperate HVAC system.
- Method of conditioning air: Air was filtered for particulates and temperature and humidity controlled.
- System of generating particulates/aerosols: Test atmosphere was generated by heating nitrogen to 200°C by passing it through a 1 l stainless steel cylinder with a 1500 W band heater. The nitrogen then passed through a glass column 7.6 cm diameter and 30 cm long packed with glass beads. Test material was delivered by a metering pump into Teflon tubing, to the bottom of the column. The liquid test substance vaporized as it went up the column with the nitrogen. The vapor then went into the test chambers where dilution with the chamber ventilation air produced the desired concentrations.
- Temperature, humidity, pressure in air chamber: Air flow rate, temperature and relative humidity were monitored every half-hour during exposure.

TEST ATMOSPHERE
- Brief description of analytical method used: Measurements made hourly using gas-phase IR.
- Samples taken from breathing zone: yes

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: 2 weeks
- Proof of pregnancy: sperm-positive vaginal smear referred to as day 0 of pregnancy

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentration of the test material in the test chambers was determined by GC analysis.

Frequency of treatment:

Both males and females were exposed 6 hours per day 5 days/ week for 10 weeks before mating. After mating, females were exposed 6 hours/day, 7 days/week from Gestation Day (GD) 0 to GD 20. Dams were then removed to nesting boxes to deliver. Dams were again exposed from postnatal day (LD) 5 until weaning on LD 21.

Details on study schedule:

- F1 parental animals not mated until 10 weeks after selected from the F1 litters.
- Selection of parents from F1 generation one week after weaning.
- Age at mating of the mated animals in the study: 15-17 weeks

Remarks:

Doses / Concentrations:
0, 100, 500, 1500 ppm
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
0, 103, 495, 1480 ppm
Basis:
analytical conc.

No. of animals per sex per dose:

30, except for F2 generation in which 40 animals/sex/dose were selected. In the 1500 ppm F2 group all surviving animals were mated.

Control animals:

yes, concurrent no treatment

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily for viability and overt toxicity.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: weekly until confirmation of mating; females weighed on GD 0, 7, 14, 21, and LD 0, 7, 14, 21

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes, weekly except during mating, gestation, and lactation
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data

Litter observations:

STANDARDISATION OF LITTERS
Litters were culled by random selection to 8 pups on LD4.


PARAMETERS EXAMINED
The following parameters were examined in F1/F2/F3 offspring:
Number of pups, stillbirths, live births, presence of gross anomalies was examined as soon as possible after delivery. Pups weighed individually on LD 0, 4, 7, 14. On LD21 all pups were counted, sexed, and weighed.


GROSS EXAMINATION OF DEAD PUPS:
Yes, culled pups and any pups that died were necropsied for gross abnormalities.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals were necropsied at end of mating period.
- Maternal animals: All surviving animals were necropsied following weaning.

HISTOPATHOLOGY
In control and high dose group the epididymis, lung, ovary, pituitary, prostate, seminal vesicle, testis, uterus, vagina, lymph nodes were examined. Masses and gross lesions were examined from all groups.

ORGAN WEIGHTS
Epididymis, lung, ovary, testis, prostate/seminal vesicle, uterus/vagina

Postmortem examinations (offspring):

SACRIFICE
- The F1/F2 offspring not selected as parental animals were sacrificed at 8 days of age. F3 offspring were sacrificed at LD21.

GROSS NECROPSY
Culled pups and any pups that died were necropsied for gross abnormalities.

HISTOPATHOLOGY / ORGAN WEIGTHS
F1/F2 offspring were examined the same as parental animals.

Statistics:

Fertility indices and female/male ratio was analysed using Chi-square test criterion with Yate's correction. Proportions of litters with malformations were compared using Fisher's exact probability test. Proportions of resorbed fetuses, implantation losses, and pup survival were compared using Mann-Whitney U test. Mean number of liveborn pups/litter and pup weight were compared using analysis of variance and appropriate t-tests. Other parameters were compared using analysis of variance, appropriate t-test, and Dunnett's multiple comparison tables.

Reproductive indices:

female mating index: number pregnant females/number of females mated
female conception index: number females delivering live litter/number pregnant females
female gestational index: number of females delivering live litter/number females delivering a litter
male fertility index: number of fertile males/number of males mated
Cohabitation time: average number male/female cohabitation days litter size at birth

Offspring viability indices:

Gestational survival index: number pups live born/number of pups born
Postnatal survival index (4-day): number pups alive at LD4/number of liveborn pups
Postnatal survival index (21-day): number pups alive at LD21/number of liveborn pups

Clinical signs:

no effects observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

no effects observed

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

F0
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
All males survived with minimal signs of toxicity. 7 females in the 1500 ppm group died.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Body weight gain of P males and females was significantly reduced in the 500 ppm and 1500 ppm groups. Food consumption was reduced in the 1500 ppm group in the first week.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There were no significant differences in number of mated females, number of females delivering a litter, number of females delivering a live litter, or male fertility. The mean number of live births per litter were not significantly reduced. Length of time for mating was not significantly different from controls.

GROSS PATHOLOGY (PARENTAL ANIMALS)
There were no significant pathological findings in the reproductive organs in any group of animals in any generation in any dose group.

F1
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
In the 1500 ppm group ataxia and reduced motor activity was observed. 6 females in this group also died.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Mean body weights of 1500 ppm group, and males in the 500 ppm group were significantly less than control groups. Food consumption was normal.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
Length of time for mating was increased, but not significantly. Male fertility was reduced, however, as this effect was not seen in the first and third generations, this is not considered to be exposure related.

F2
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
Most of the animals (36/40 males and 34/40 females) in the high exposure group (1500 ppm) died within the first week.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Body weight gain of high exposure males and females were severely below control (up to 40%). Body weights in the 500 ppm and 100 ppm exposure groups were mildly depressed (10%). Food consumption was similar for all groups.

Key result

Dose descriptor:

NOAEC

Effect level:

>= 1 500 ppm

Sex:

male/female

Basis for effect level:

other: 7800 mg/m3; If maternal exposure ceased before gestation day 20, there were no negative effects on the offspring.

Remarks on result:

other: Generation: offspring of all generations (migrated information)

Key result

Dose descriptor:

LOAEC

Effect level:

1 500 ppm

Sex:

male/female

Basis for effect level:

other: 7800 mg/m3; Reduced body weight in offspring was noted if maternal exposure was continued until delivery.

Remarks on result:

other: Generation: offspring of all generations (migrated information)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

F1
VIABILITY (OFFSPRING)
No significant differences through the lactation period.

BODY WEIGHT (OFFSPRING)
No significant difference in body weights or birth weight, except for pups from the 1500 ppm group at LD7 through weaning.

F2
VIABILITY (OFFSPRING)
Mean birth weight in the 1500 ppm group was reduced, but not significantly. The mean number of live offspring/litter, and number live-born/number delivered was significantly reduced in this group. This was most likely due to litters from dams which had not been confirmed to have mated. These unconfirmed dams were exposed until delivery, whereas the other dams were not exposed after GD20. The birth weights from these litters were not significantly reduced.

BODY WEIGHT (OFFSPRING)
Mean body weights in the 1500 ppm group after LD7 were significantly reduced.

F3
VIABILITY (OFFSPRING)
There were no apparent effects on mating, fertility, mean number of live births, and survival through lactation period.

BODY WEIGHT (OFFSPRING)
Mean weight of the offspring in the high exposure group was significantly reduced at birth. This may have been the result of the small sizes of the dams. If maternal exposure was ceased, the body weight gain became normal, but if reinitiated, the body weights were again reduced.

Key result

Dose descriptor:

NOAEC

Generation:

F2

Effect level:

>= 1 500 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Fertility Effects

Key result

Dose descriptor:

LOAEC

Generation:

F2

Effect level:

1 500 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Fertility effects

Reproductive effects observed:

not specified

Significant Effects of Exposure to High Flash Aromatic Naptha (SD)

Male Fertility Index	F0	F1	F2
0	86.7 (30)	89.7 (30)	93.3 (30)
100	96.7 (30)	86.7 (30)	83.3 (30)
500	83.3 (30)	93.3 (30)	80.0 (30)
1500	84.6 (26)	64.3 (28)	100 (4)
Litter Size at Birth	F0	F1	F2
0	12.1 ± 3.4	12.4 ± 2.0	12.6 ± 2.7
100	12.9 ± 1.5	11.1 ± 2.9	11.8 ± 2.3
500	12.2 ± 3.1	11.7 ± 3.0	11.4 ± 2.1
1500	11.3 ± 3.0	8.7 ± 4.3	12.2 ± 1.3
Gestational Survival Index	F1	F2	F3
0	95.9 (366)	97.4 (383)	97.7 (361)
100	97.9 (382)	95.4 (280)	98.2 (335)
500	94.9 (333)	91.6 (371)	98.5 (325)
1500	92.8 (279)	85.1 (215)	100 (73)

 

Gestational Survival Index Among Rats in the F2 Generation

Concentration	Total % (SD)	Prolonged Exposure (%) SD	Exposure Stopped on GD20 (%) SD
0	97.4 (383)	91.9 (74)	98.7 (309)
100	95.4 (280)	91.7 (96)	97.2 (184)
500	91.6 (371)	30.8 (13)	93.8 (358)
1500	85.1 (215)	63.0 (54)	92.5 (161)

 

Body Weights of Pups

Concentration (ppm)	F1	F2	F3
	Day 0
0	6.1± 0.5	6.0 ±0.5	6.0 ±0.5
100	6.2 ±0.5	6.1 ±0.5	6.0 ±0.4
500	6.5 ±0.6	6.0± 0.5	6.1 ±0.6
1500	6.1± 1.0	5.7 ±0.7	5.7 ±0.2
	Day 4
0	9.7 ±0.9	9.5 ±1.4	9.7 ±1.1
100	9.8 ±0.6	10.0± 1.2	10.0 ±0.7
500	10.1 ±1.0	9.9 ±1.0	9.8 ±1.0
1500	9.2 ±1.3	9.3 ±1.0	9.2 ±0.6
	Day 7
0	13.7 ±1.3	13.3 ±1.8	14.0±2.0
100	13.2 ±1.1	13.3 ±1.6	14.1 ±1.2
500	14.0 ±1.7	13.5 ±1.4	13.4 ±1.5
1500	12.0 ±1.8	11.7 ±1.3	12.0 ±1.0
	Day 14
0	24.9± 2.7	24.3 ±2.5	26.2± 4.0
100	23.2 ±1.8	23.5 ±2.8	25.6 ±1.9
500	23.9 ±2.4	23.7 ±2.7	23.2 ±2.7
1500	19.6 ±2.7	19.3 ±1.8	20.8 ±1.3
	Day 21 Male Body Weights
0	39.5 ±5.1	40.9 ±5.5	42.9 ±7.6
100	37.2 ±5.9	39.3 ±5.5	42.7 ±3.8
500	40.0 ±4.9	39.7 ±5.6	38.7± 5.1
1500	29.9 ±3.6	30.4 ±4.2	32.8 ±3.0
	Day 21 Female Body Weights
0	38.0 ±5.0	39.6 ±5.1	41.4 ±6.2
100	35.7 ±5.7	37.9 ±4.8	41.2 ±3.6
500	38.0 ±5.0	38.6 ±5.5	37.2 ±4.8
1500	29.4 ±4.3	29.1 ±4.2	31.8 ±3.6

Conclusions:

The test substance NOAEC for fertility effects is 1500 ppm for male and female rats.

Executive summary:

This study was conducted to determine the reproductive toxicity of high flash aromatic naphtha. 30 rats of each sex (F0 generation) were exposed via inhalation to 100, 500, or 1500 ppm of high flash aromatic naphtha for 6 hrs/day, 5 days/week for 10 weeks. Rats were then mated, and females confirmed mated were then exposed for 6 hrs/day during gestation days 0 to 20. Dams were not exposed during delivery, but exposure was reinitiated on postnatal day 5 and continued through postnatal day 21 (weaning). This F1 generation was then exposed for 10 weeks starting at 5 to 7 weeks of age, then mated to produce the F2 generation. The F2 generation was treated similarly to the F1 generation, except they were exposed immediately after weaning to produce the F3 generation. Under these conditions, reduced survival and body weight gains were observed in the offspring of the high exposure group. Although this was evidence of a toxic effect at the highest dose tested, there were no reproductive effects.

 

Fertility indices were calculated for all parental generations (F0, F1, and F2), female mating index, female conception index, female gestation index, male fertility index, cohabitation time, and litter size at birth. The gestational survival and postnatal survival indexes of the F1, F2, and F3 generations were also calculated. The results of the fertility study show no exposure related adverse effects to fertility in either male or female rats, therefore the NOAEC for fertility is 1500 ppm for high flash aromatic naphtha. 

Reference 2

Endpoint:

extended one-generation reproductive toxicity - with developmental neurotoxicity (Cohorts 1A, 1B without extension, 2A and 2B)

Data waiving:

other justification

Justification for data waiving:

other:

Justification for type of information:

The 'Justification for the read across' is provided in the 'Attached justification' section below.

Species:

rat

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

Study duration:

subchronic

Experimental exposure time per week (hours/week):

30

Species:

rat

Quality of whole database:

One key read across study from a structural analogue available for assessment.

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

There is no substance specific data available for Hydrocarbons, C10-C13, aromatics, >1% naphthalene. However, data is available for structural analogue, C9 aromatics and presented in the dossier. This data is read across to Hydrocarbons, C10-C13, aromatics, >1% naphthalene based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

C9 Aromatics

 

A key study (McKee et al. 1990) was conducted to determine the reproductive toxicity of high flash aromatic naphtha. 30 rats of each sex (F0 generation) were exposed via inhalation to 100, 500, or 1500 ppm of high flash aromatic naphtha (C9 Aromatics) for 6 hrs/day, 5 days/week for 10 weeks. Rats were then mated, and females confirmed mated were then exposed for 6 hrs/day during gestation days 0 to 20. Dams were not exposed during delivery, but exposure was reinitiated on postnatal day 5 and continued through postnatal day 21 (weaning). This F1 generation was then exposed for 10 weeks starting at 5 to 7 weeks of age, then mated to produce the F2 generation. The F2 generation was treated similarly to the F1 generation, except they were exposed immediately after weaning to produce the F3 generation. Under these conditions, reduced survival and body weight gains were observed in the offspring of the high exposure group. Although this was evidence of a toxic effect at the highest dose tested, there were no reproductive effects.

 

Fertility indices were calculated for all parental generations (F0, F1, and F2), female mating index, female conception index, female gestation index, male fertility index, cohabitation time, and litter size at birth. The gestational survival and postnatal survival indexes of the F1, F2, and F3 generations were also calculated. The results of the fertility study show no exposure related adverse effects to fertility in either male or female rats, therefore the NOAEC for fertility is 1500 ppm for high flash aromatic naphtha. 

Additionally, in order to comply with standard information requirements for Annex X substances, OECD 443 tests are proposed for structural analogues, Hydrocarbons, C9-C10, aromatics >1% Naphthalene (EC# 946-365-8) and Hydrocarbons C11-C15 Aromatics <1% Naphthalene (EC# 922-153-0). This read across is based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in Section 13.2 of the dossier. This endpoint will be updated subsequent to ECHA's approval of the testing proposal and availability of data upon completion of the study.

Effects on developmental toxicity

Description of key information

Developmental toxicity data in rats is available for Hydrocarbons, C10-C13, aromatics, >1% naphthalene. This is supported by data available in rats from a structural analogue Hydrocarbons, C9, aromatics and data in rats and rabbits from Naphthalene. This data is read across to Hydrocarbons, C10-C13, aromatics, >1% naphthalene based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Hydrocarbons, C10-C13, aromatics, >1% naphthalene

Developmental (oral) NOAEL >450 mg/Kg/day (Rat)

Naphthalene

Developmental (oral) NOAEL >450 mg/Kg/day (Rat)

Developmental (oral) NOAEL >120 mg/Kg/day (Rabbit)

Hydrocarbons, C9, aromatics

Developmental (inhalation) NOAEC = 100 ppm (Rat)

Additionally, OECD Guideline 414 (Prenatal Developmental Toxicity) rodent and non-rodent species tests are proposed for structural analogues, Hydrocarbons, C9-C10, aromatics >1% Naphthalene (EC# 946-365-8) and Hydrocarbons C11-C15 Aromatics <1% Naphthalene (EC# 922-153-0). The testing proposals have been presented in the lead registrant dossiers for these substances already submitted to ECHA. This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Link to relevant study records

Reference

Reference 1

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991/05/07-1991/06/12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD Guideline 414.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Details on test animals or test system and environmental conditions:

TEST ANIMALS
Sex: Male (50), Female (100)
Weight (Female): 242 - 340 g (day 0)
Age at study initiation: Approximately 10-11 weeks
Housing: Individually
Diet (e.g. ad libitum): Purina Certified Rodent 5002 Chow, ad libitum
Water (e.g. ad libitum): Automatic watering system, ad libitum
Acclimation period: 21d

ENVIRONMENTAL CONDITIONS
Temperature (°F): 68-76
Humidity (%): 40-70%
Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

Mated females were dosed once daily by oral gavage from GD 6 through GD 15. Dose levels were based on the most recent body weights. Doses were administered at 0, 75, 150, and 450 mg/kg and dose volumes were 5 ml/kg for all groups.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

gas chromatography verification

Details on mating procedure:

Females were placed in males’ cages in a 1:1 ratio based on sequential ID numbers. Mating was confirmed the following morning by observation of a copulatory plug or by the presence of sperm in a vaginal rinse. The day mating was confirmed was the female’s day 0 of gestation (GD 0). After confirmed mating, the female was returned to her own cage and a new female was placed into the male’s cage until the required number of mated females was obtained by continuous cohabitation.

Duration of treatment / exposure:

Mated females were dosed once daily by oral gavage from GD 6 through GD 15. Dose levels were based on the most recent body weights. Doses were administered at 0, 75, 150, and 450 mg/kg and dose volumes were 5 ml/kg for all groups.

Frequency of treatment:

Mated females were dosed once daily by oral gavage from GD 6 through GD 15.

Duration of test:

21 days

No. of animals per sex per dose:

Male (50), Female (100) total; 25 Females per dose

Control animals:

yes

Details on study design:

PARAMETERS Analyzed for Statistical Differences
- mean body weight and gravid uterine weight of pregnant animals
- mean body weight change of pregnant animals
- mean food consumption of pregnant animals
- mean number of corpora lutea per dam
- mean number of implantations per dam
- mean number of resorptions per dam
- mean number of live fetuses per litter
- mean number of live male fetuses per litter
- mean number of live female fetuses per litter
- mean number of dead fetuses per litter
- mean number of malformed fetuses per litter
- mean number of affected (resorbed, dead or malformed) offspring per litter
- mean number of fetuses with developmental variations per litter

Live fetuses as fraction of implants, dead fetuses as fraction of implants, and resorptions as fraction of implants, were calculated for each litter. Fractions were transformed by Cochran’s transformation followed by the arc sine transformation. The raw fractions and the transformed fractions were tested for statistical significance. Transformed percentages (with statistical analyses) were not presented in the report since statistical significance was not found.

Maternal examinations:

All females were examined by a gross necropsy.

Ovaries and uterine content:

Uterine weight with ovaries attached was measured at necropsy. Uterine contents were examined and the numbers and locations of implantation sites, early and late resorptions, live, dead, and externally malformed fetuses were recorded. Corpora lutea were counted and recorded. The uteri of all apparently non-pregnant dams were stained to confirm pregnancy status.

Fetal examinations:

Each live fetus was weighed and examined externally for gross malformations, including cleft palate. All live fetuses were euthanized by intramuscular injection into the tongue with sodium pentobarbital prior to internal examination. The sex of each live fetus was determined by external examination and confirmed internally only on those fetuses receiving visceral examinations.

Approximately one-half of the fetuses of each litter were decapitated. These heads were preserved in Bouin’s solution for at least two weeks. Free-hand razor blade sections of the heads were examined for the presence of abnormalities. The viscera of all decapitated fetuses were also examined by fresh dissection. The remaining fetuses were eviscerated, processed for skeletal staining with Alizarin red, and examined for the presence of malformations and ossification variations. Representative malformations were photographed.

Statistics:

STATISTICAL METHODS (see "Further details on study design" field for parameters measured)

Bartlett’s test of homogeneity of variance was used to determine if the groups had equivalent variances at the 1% level of significance.

1. If the variances were equivalent, the hypothesis that there was no difference in response between the groups was tested using a one-way ANOVA, and if it was significant, Dunnett’s test was performed to determine which treatment groups differed from the control. A linear regression to test for a dose response was also performed and tested for lack of fit to the regression.

2. If the variances were not equivalent, then a Kruskal-Wallis (non-parametric) test was performed to determine if the treatment effects were equivalent. If there was a difference, a rank sum comparison was used to determine which treatment groups differed from the control. Jonckheere’s test for ordered response was also performed.


The following were calculated and analyzed for statistical significance:
- incidences of individual and total malformations
- incidences of individual and total variations
A standard chi square analysis was performed to determine if the proportion of incidences differed between the groups tested. Each group was then compared to each control group using a 2 x 2 Fisher Exact test. Armitage’s test for linear trend in the dosage groups was performed.

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
CLINICAL IN-LIFE OBSERVATIONS
Low incidences of alopecia, urine staining, nasal discharge, red material around snout, dry rales, swollen area, soft stool, and mal-occluded or broken incisors were observed intermittently throughout the groups and considered incidental and unrelated to treatment. All animals survived to the scheduled cesarean sections on 21G. One animal in each of the low and high dose groups, and three animals in the mid-dose group were not pregnant.

BODY WEIGHTS
There were no significant differences in mean body weight at any interval between treated groups and controls. However, there was a noted body weight gain suppression observed in the treated groups when compared to controls, with the high dose group demonstrating a statistically significant change (GD 6-15). Overall body weight differences were not significant (GD 0-21).

FOOD CONSUMPTION
A significant decrease in mean maternal food consumption was observed in the high dose group at the GD 6-9 interval when compared with controls. Overall (GD 0-21) there were no significant changes observed in any of the treated groups when compared to the control group.

ORGAN WEIGHT
No significant changes.

MATERNAL NECROPSY OBSERVATIONS
The incidental findings observed at necropsy were not attributed to the treatment.

UTERINE IMPLANTATION DATA
There were no statistical differences between treated and control animals for any uterine implantation parameter.

Key result

Dose descriptor:

NOAEL

Effect level:

150 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

NOAEL

Effect level:

> 450 mg/kg bw/day

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
FETAL BODY WEIGHTS
There were no statistical differences between treated and control groups.

FETAL VARIATIONS AND MALFORMATIONS
There were no statistical differences in the incidences of fetal variations or malformations were observed in treated groups when compared with controls on either a per fetus or per litter basis. Visceral variations were observed in all groups included dilated renal pelvis and distended and/or convoluted ureters. Umbilical artery and/or vein on the left side of the urinary bladder were observed in one fetus in the control group and in two fetuses from two litters in the mid-dose group. No innominate artery was observed in two fetuses from one litter in the low dose group. Skeletal variations were observed throughout the groups and consisted primarily of hypoplastic or misshapen elements of the skull, sternebrae, vertebrae, or ribs. These findings are common in gestation day 21 rat fetuses and the incidence or severities were not considered treatment-related.

The majority of malformations were observed in a single instance in the low and high dose as well as additional malformations in control animals. External malformations included cleft palate, low set ears, anury, and anal atresia. Visceral malformations were also correlative to those fetuses with external malformations. Skeletal malformations were observed throughout the dose groups and consisted primarily of single instances of malformed or fused skull bones, agenesis of the ribs, vertebral arches or centra, and duplicates or extra bones of the hind paw. All malformations were considered spurious and unrelated to treatment.

FETAL SKELETAL OSSIFICATION SITES
There was a statistically significant decrease in the mean number of ossification sites in the proximal phalanges of the hindpaw in the high dose group. However, the number falls within the normal range of 0-3 and the decrease in the high dose group was not considered biologically significant.

Key result

Dose descriptor:

NOAEL

Effect level:

> 450 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: Developmental Toxicity

Abnormalities:

not specified

Key result

Developmental effects observed:

no

Conclusions:

The maternal NOAEL was determined to be 150 mg/kg and a developmental NOAEL was determined to be greater than 450 mg/kg. MRD-90-884 was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS or the EU Requirements for dangerous substances and preparations guidelines.

Executive summary:

The objective of this study was to determine the teratogenic potential of MRD-90-884 when administered to pregnant rats during gestational day (GD) 6 through GD 15.  The test material was administered by oral gavage at doses of 75, 150, and 450 mg/kg at a volume of 5 ml/kg. There were no treatment-related clinical in-life observations or any observable abnormalities in the dams for any dose group.  All animals survived to scheduled cesarean sections on GD 21.   There were no significant differences between treated and control animals for any uterine implantation parameter.  Mean fetal body weights for treated groups were comparable to control groups.  There were no statistically significant differences in the incidences of total or individual variations or malformations when analyzed on either a fetus or litter basis.  The maternal NOAEL was established as 150 mg/kg and a developmental NOAEL was established as greater than 450 mg/kg.  MRD-90-884 was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS or the EU requirements for dangerous substances and preparations guidelines.

Reference 2

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS

Source: Hazelton Research Products, Inc., Denver, PA
Sex: Female
Weight (Female): 2830-4230 g (day 0)
Age at study initiation: Approximately 6.5 months
Housing: Individually
Diet (e.g. ad libitum): Purina Certified Rabbit 5322 Chow, ad libitum
Water (e.g. ad libitum): Deionized/filtered water
Acclimation period: 14d

ENVIRONMENTAL CONDITIONS
Temperature (°F): 66
Humidity (%): 43-73% in first replicate and 50-75% second replicate
Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Remarks:

Mazola

Details on exposure:

Time-mated rabbits were administered naphthalene (20, 80 or 120 mg/kg) or vehicle by gavage in a volume of 2 ml/kg body weight from gestation days (GD) 6-19.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

gas chromatography verification

Details on mating procedure:

After a fourteen day quarantine period, females were artificially inseminated. The day of insemination was designated as gestational day (GD) 0.

Duration of treatment / exposure:

Mated females were dosed once daily by oral gavage from GD 6 through GD 19. Dose levels were based on the most recent body weights. Doses were administered at 0, 20, 80, and 120 mg/kg and dose volumes were 2 ml/kg body weight for all groups.

Frequency of treatment:

Mated females were dosed once daily by oral gavage from GD 6 through GD 19.

Duration of test:

31 days

No. of animals per sex per dose:

25-27 pregnant females per dose

Control animals:

yes

Details on study design:

The study was performed in two replicates with 2 consecutive breeding dates in each replicate. The last breeding date for the first replicate and the first breeding date of the second replicate were 54 days apart.

Maternal examinations:

Time-mated does were weighed on the mornings of GD 0, 6 through 19, 25 and 30. Food was weighed on GD 0, 3, 6, 9, 12, 15, 18, 19, 22, 25, 28 and 30. Animals were observed daily, before (GD 0-5) and after (GD 20-30) the dosing period, for clinical signs of toxicity. During the dosing period, the does were observed before and at least once after dosing.

Ovaries and uterine content:

Maternal body, liver and intact uterus were weighed and corpora lutea counted. Uterine contents were examiend to determine the number of implantation sites, resorptions, dead fetuses and live fetuses. Uteri which had no visible implantation sites were stained with ammonium sulfide (10%) to detect very early resorptions.

Fetal examinations:

Live fetuses were dissected from the uterus and anesthesized with sodium pentobarbital. They were weighed, examined for external morphological abnormalities and dissected for visceral examination by a fresh tissue dissection technique. Half of the fetuses were decapitated prior to dissection; the heads were fixed in Bouin's solution and then examined by a free-hand sectioning technique. All fetal carcases were stained with alcian blue/alizarin red S and examined for skeletal malformations.

Statistics:

STATISTICAL METHODS

General linear Models (GLM) procedures, were applied for the analyses of variance (ANOVA) of maternal and fetal parameters . Prior to GLM analysis, an arcsine-square root transformation was performed on all litter-derived percentage data and Bartlett's test for homogeneity of variance was
performed on all data to be analyzed by ANOYA . GLM analysis determined the significance of dose-response relationships and the significance
of dose effects, replicate effects and dose x replicate interactions. When ANOVA revealed a significant (p0.05) dose x replicate effects on selected fetal parametric measures wire considered justification for pooling data across replicates for nonparametric analysis on related measures. When a significant (p<0.05) dose x replicate interaction occurred, the data for that endpoint and for any related nominal scale data were analyzed separately for dose effects within each replicate in the study, as well as for all replicates combined. Nominal scale measures were analyzed by a X2 test for independence and by a test for linear trend on proportions. When a x2 test showed significant group differences, a one-tailed Fisher's exact probability test was used for pairwise comparisons of NAP and control groups.

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
CLINICAL IN-LIFE OBSERVATIONS
There were no naphthalene-related maternal deaths during the study. Consistent treatment-related signs of clinical toxicity were not seen, Diarrhea was common during the dosing period but was comparable in control and treated groups. The effect was thus assumed to be related to the use of corn oil as vehicle.

BODY WEIGHTS
Maternal body weight before, during and after the treatment period was not significantly affected by naphthalene treatment. Maternal weight gain, during the dosing period, displayed a dose dependent decreasing trend. However the actual magnitude of the changes was small. Weight changes of +0.5% (20 mg/kg) to -2.5% (120 mg/kg) of pre-dosing maternal body weight, as compared to 1.3% weight gain in the control group, was observed.

FOOD CONSUMPTION
MAternal relative food consumption did not show any treatment-related changes, except for a significant transient elevation in the 120 mg/kg dose group on GD 19-25.

ORGAN WEIGHT
Gravid uterine and absolute and/or relative maternal liver weights were unaffected by treatment.

MATERNAL NECROPSY OBSERVATIONS
The incidental findings observed at necropsy were not attributed to the treatment.

UTERINE IMPLANTATION DATA
There were no statistical differences between treated and control animals for any uterine implantation parameter.

Key result

Dose descriptor:

NOAEL

Effect level:

> 120 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

NOAEL

Effect level:

> 120 mg/kg bw/day

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Results of the uterine examination revealed that the number of corpora lutea per doe and the number of implantation sites per litter in the naphthalene-treated animals were within 101%-108% of control values. No consistent effect of dose was seen for the percent preimplantation loss or the percent resorptions per litter. Likewise. the percent litters with adversely affected implants was comparable to control values. The number of live fetuses per litter and the average fetal body weight (male or female) in the naphthalene groups were also similar to controls. The overall incidence of malformations in males was 2.7%. 4.4%. 2.7%. and 0.0% in the control, 20, 80, and 120 mg/kg/day naphthalene groups, respectively. Naphthalene did not affect the incidence of variations (either sex) on either a per fetus or a per litter basis. Likewise, the number of fetuses or litters with defects (one or more malformation or variation) was unaffected by naphthalene administration.

Key result

Dose descriptor:

NOAEL

Effect level:

> 120 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: Developmental Toxicity

Abnormalities:

not specified

Key result

Developmental effects observed:

no

Conclusions:

Maternal and fetal NOAEL were greater than highest dose tested. Naphthalene was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS or the EU Requirements for dangerous substances and preparations guidelines.

Executive summary:

The objective of this study was to determine the teratogenic potential of naphthalene when administered to pregnant rabbits during gestational day (GD) 6 through GD 19.  The test material was administered by oral gavage at doses of 20, 80, and 120 mg/kg at a volume of 2 ml/kg. No statistically significant maternal or fetal effects were reported in the study.

Reference 3

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS

Source: Charles River Laboratories, Inc. Raleigh, NC
Sex: Female
Weight (Female): 209-271 g (day 0)
Age at study initiation: Approximately 9-11 weeks
Housing: Individually
Diet (e.g. ad libitum): Ground Purina Certified Rodent 5002 Chow, ad libitum
Water (e.g. ad libitum): Deionized/filtered water
Acclimation period: 7d

ENVIRONMENTAL CONDITIONS
Temperature (°F): 69-75
Humidity (%): 49-60% in first replicate and 44-63% second replicate
Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Remarks:

Mazola

Details on exposure:

Time-mated rats were administered naphthalene (50, 150 or 450 mg/kg) or vehicle by gavage in a volume of 5 ml/kg body weight from gestation days (GD) 6-15.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

gas chromatography verification

Details on mating procedure:

Individual breeding pairs were cohabited overnight. On the following morning, females were examined for the presence of sperm by vaginal smear. the day of sperm detection was designated as gestational day (GD) 0.

Duration of treatment / exposure:

Mated females were dosed once daily by oral gavage from GD 6 through GD 15. Dose levels were based on the most recent body weights. Doses were administered at 0, 50, 150, and 450 mg/kg and dose volumes were 5 ml/kg body weight for all groups.

Frequency of treatment:

Mated females were dosed once daily by oral gavage from GD 6 through GD 15.

Duration of test:

21 days

No. of animals per sex per dose:

25-26 pregnant females per dose

Control animals:

yes

Maternal examinations:

Time-mated females were weighed on the mornings of GD 0, 3, 6 through 15, 18 and 20. Food and water measurements were taken on GD 0, 3, 6, 9, 12, 15, 18 and 20. Animals were observed before dosing (GD 0-5_ and daily during (GD 6-15) and after (GD 16-20) dosing for clinical signs of toxicity. Rats were terminated with excess CO2 followed by cervical dislocation on GD 20.

Ovaries and uterine content:

Maternal body, liver and intact uterus were weighed and corpora lutea counted. Uterine contents were examined to determine the number of implantation sites, resorptions, dead fetuses and live fetuses. Uteri which had no visible implantation sites were stained with ammonium sulfide (10%) to detect very early resorptions.

Fetal examinations:

Live fetuses were dissected from the uterus and anesthesized on ice. They were weighed, examined for external morphological abnormalities and dissected for visceral examination by a fresh tissue dissection technique. Half of the fetuses were decapitated prior to dissection; the heads were fixed in Bouin's solution and then examined by a free-hand sectioning technique. All fetal carcases were stained with alcian blue/alizarin red S and examined for skeletal malformations.

Statistics:

STATISTICAL METHODS

General linear Models (GLM) procedures, were applied for the analyses of variance (ANOVA) of maternal and fetal parameters . Prior to GLM analysis, an arcsine-square root transformation was performed on all litter-derived percentage data and Bartlett's test for homogeneity of variance was
performed on all data to be analyzed by ANOYA . GLM analysis determined the significance of dose-response relationships and the significance
of dose effects, replicate effects and dose x replicate interactions. When ANOVA revealed a significant (p0.05) dose x replicate effects on selected fetal parametric measures wire considered justification for pooling data across replicates for nonparametric analysis on related measures. When a significant (p<0.05) dose x replicate interaction occurred, the data for that endpoint and for any related nominal scale data were analyzed separately for dose effects within each replicate in the study, as well as for all replicates combined. Nominal scale measures were analyzed by a X2 test for independence and by a test for linear trend on proportions. When a x2 test showed significant group differences, a one-tailed Fisher's exact probability test was used for pairwise comparisons of NAP and control groups.

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
CLINICAL IN-LIFE OBSERVATIONS
Lethargy, slow breathing and prone body posture were the most common clinical signs during the first five days of dosing, with the incidence of these effects showing a marked dose-dependence. There was a trend towards diminishing clinical signs with prolonged exposure, evidence that the dams acquired tolerance to these effects. An increased incidence of rooting behaviour (typical wigh exposure to a substance with noxious odor or local irritant) was noted as dosing progressed, primarily in the mid and high dose groups.

BODY WEIGHTS
Naphthalene caused a significant dose-dependent decrease in maternal body weight and body weight gain; the effect confined to the two highest dose groups. Maternal body weights in the two highest dose groups remained consistently below control values (6-12%) throughout dosing and trend persisted until sacrifice on GD 20.

FOOD CONSUMPTION
Maternal food and water consumption was reduced in the two highest dose groups. However, by GD 9-12, food consumption in the two groups had returned to control levels. A significant elevation in food consumption was noted on GD 18-20 in the high dose group.

ORGAN WEIGHT
No significant changes.

MATERNAL NECROPSY OBSERVATIONS
The incidental findings observed at necropsy were not attributed to the treatment.

UTERINE IMPLANTATION DATA
There were no statistical differences between treated and control animals for any uterine implantation parameter.

Key result

Dose descriptor:

NOAEL

Effect level:

< 50 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

NOAEL

Effect level:

> 450 mg/kg bw/day

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
FETAL BODY WEIGHTS
There were no statistical differences between treated and control groups.

FETAL VARIATIONS AND MALFORMATIONS
There were no statistical differences in the incidences of fetal variations or malformations were observed in treated groups when compared with controls on either a per fetus or per litter basis. Visceral variations were observed in all groups included dilated renal pelvis and distended and/or convoluted ureters. Umbilical artery and/or vein on the left side of the urinary bladder were observed in one fetus in the control group and in two fetuses from two litters in the mid-dose group. No innominate artery was observed in two fetuses from one litter in the low dose group. Skeletal variations were observed throughout the groups and consisted primarily of hypoplastic or misshapen elements of the skull, sternebrae, vertebrae, or ribs. These findings are common in gestation day 21 rat fetuses and the incidence or severities were not considered treatment-related.

The majority of malformations were observed in a single instance in the low and high dose as well as additional malformations in control animals. External malformations included cleft palate, low set ears, anury, and anal atresia. Visceral malformations were also correlative to those fetuses with external malformations. Skeletal malformations were observed throughout the dose groups and consisted primarily of single instances of malformed or fused skull bones, agenesis of the ribs, vertebral arches or centra, and duplicates or extra bones of the hind paw. All malformations were considered spurious and unrelated to treatment.

FETAL SKELETAL OSSIFICATION SITES
There was a statistically significant decrease in the mean number of ossification sites in the proximal phalanges of the hindpaw in the high dose group. However, the number falls within the normal range of 0-3 and the decrease in the high dose group was not considered biologically significant.

Key result

Dose descriptor:

NOAEL

Effect level:

> 450 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: Developmental Toxicity

Abnormalities:

not specified

Key result

Developmental effects observed:

no

Conclusions:

The maternal NOAEL was determined to be <50 mg/kg as a result of decreased maternal body weight at termination of study (150 and 450 mg/kg) and evidence for CNS depression at all doses. There were no statistically significant fetal effects and fetal NOAEL was determined to be greater than 450 mg/kg. Naphthalene was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS or the EU Requirements for dangerous substances and preparations guidelines.

Executive summary:

The objective of this study was to determine the teratogenic potential of naphthalene when administered to pregnant rats during gestational day (GD) 6 through GD 15.  The test material was administered by oral gavage at doses of 50, 150, and 450 mg/kg at a volume of 5 ml/kg. Clinical observations in the dams were limited to body weight effects and evidence for CNS depression which improved with prolonged dosing. Two dams died during dosing. However both dams were in the 50 mg/kg dose group and the deaths were considered unrelated to dosing. Maternal NOAEL was established to be <50 mg/kg as a result of evidence for CNS depression. No fetal effects were found to be statistically significant to controls hence NOAEL was determined to be greater than the highest dose tested.

Reference 4

Endpoint:

developmental toxicity

Data waiving:

other justification

Justification for data waiving:

other:

Justification for type of information:

The 'Justification for the read across' is provided in the 'Attached justification' section below

Species:

rat

Reference 5

Endpoint:

developmental toxicity

Data waiving:

other justification

Justification for data waiving:

other:

Justification for type of information:

The 'Justification for the read across' is provided in the 'Attached justification' section below.

Species:

rabbit

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

450 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

One key substance specific and two read across studies from structural analogues available for assessment.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEC

Study duration:

subacute

Species:

rat

Quality of whole database:

One key read across study from a structrual analogue available for assessment.

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Developmental toxicity data in rats is available for Hydrocarbons, C10-C13, aromatics, >1% naphthalene. This is supported by data available in rats from a structural analogue Hydrocarbons, C9, aromatics and data in rats and rabbits from Naphthalene. This data is read across to Hydrocarbons, C10-C13, aromatics, >1% naphthalene based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Oral

Hydrocarbons, C10-C13, aromatics, >1% naphthalene

 

A key prenatal developmental toxicity study (ExxonMobil, 1992) was conducted to determine the teratogenic potential of the test material (Hydrocarbons, C10-C13, aromatics, >1% naphthalene) when administered to pregnant rats during gestational day (GD) 6 through GD 15. The test material was administered by oral gavage at doses of 75, 150, and 450 mg/Kg at a volume of 5 mL/Kg. There were no treatment-related clinical in-life observations or any observable abnormalities in the dams for any dose group. All animals survived to scheduled caesarean sections on GD 21. There were no significant differences between treated and control animals for any uterine implantation parameter. Mean fetal body weights for treated groups were comparable to control groups. There were no statistically significant differences in the incidences of total or individual variations or malformations when analysed on either a fetus or litter basis. The maternal NOAEL was established as 150 mg/Kg and a developmental NOAEL was established as greater than 450 mg/Kg. Hydrocarbons, C10-C13, aromatics, >1% naphthalene was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS guideline.

 

Naphthalene

 

A key study (NTP, 1992) was conducted to determine the teratogenic potential of naphthalene when administered to pregnant rabbits during gestational day (GD) 6 through GD 19. The test material was administered by oral gavage at doses of 20, 80, and 120 mg/Kg at a volume of 2 ml/Kg. No statistically significant maternal or fetal effects were reported in the study. Maternal and fetal NOAEL were greater than highest dose tested. Naphthalene was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS guideline.

 

A second key study (NTP, 1991) was conducted to determine the teratogenic potential of naphthalene when administered to pregnant rats during gestational day (GD) 6 through GD 15. The test material was administered by oral gavage at doses of 50, 150, and 450 mg/Kg at a volume of 5 mL/Kg. Clinical observations in the dams were limited to body weight effects and evidence for CNS depression which improved with prolonged dosing. Two dams died during dosing. However both dams were in the 50 mg/Kg dose group and the deaths were considered unrelated to dosing. The maternal NOAEL was established to be <50 mg/Kg as a result of evidence for CNS depression. No fetal effects were found to be statistically significant to controls hence NOAEL was determined to be greater than the highest dose tested (>450 mg/Kg). Naphthalene was not teratogenic under the conditions of this study and would not warrant classification under either the EU GHS guideline.

Additionally, OECD Guideline 414 (Prenatal Developmental Toxicity) rodent and non-rodent species tests are proposed for structural analogues, Hydrocarbons, C9-C10, aromatics >1% Naphthalene (EC# 946-365-8) and Hydrocarbons C11-C15 Aromatics <1% Naphthalene (EC# 922-153-0). The testing proposals have been presented in the lead registrant dossiers for these substances already submitted to ECHA. This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Inhalation

Hydrocarbons, C9, aromatics

 

A key study (McKee et al., 1990) was conducted to determine the developmental toxicity of high flash aromatic naphtha (Hydrocarbons, C9, aromatics). Groups of 30 pregnant female mice were exposed via inhalation to 100, 500, or 1500 ppm of high flash aromatic naphtha for 6 hrs per day during gestation days 6 -15. The mice were sacrificed on gestation day 18, and examined for a variety of fetal developmental parameters including number of viable and nonviable fetuses, number of resorptions, total implantations, and number of corpora lutea. Animals were also examined for maternal toxicity signs including body weight, and changes in appearance and behaviour.

 

There was a statistically significant reduction in body weight gain in dams and reduced mean body weight for fetuses in the 500 ppm exposure group. Therefore, the maternal and developmental toxicity NOAEC = 100 ppm. The maternal toxicity LOAEC was 500 ppm based on significant reduction in weight gain for the dams. The development toxicity LOAEC was 500 ppm based on significant reduction in weight gain likely caused by the significant reduction in maternal body weight.

Justification for classification or non-classification

Based on the available substance specific and read across data, Hydrocarbons, C10-C13, aromatics, >1% naphthalene does not warrant classification for reproductive or developmental toxicity under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).