Distillates (coal tar), heavy oils

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

- Soft-tissue examinations only on 1/3 instead of 1/2 of the foetuses. Post-treatment period of five days prior to caesarean sect.: Acc. to OECD TG 414 (22 Jan. 2001), dosage should cover the whole pregnancy up to 1 d prior to scheduled caesarean sect.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Creosote - US P1/P3

IUPAC Name:

Creosote - US P1/P3

Details on test material:

US Type P1/13 based on GC/MS (Selection of Key Compounds)

- Substance type: organic
- Physical state: liquid

Distilled Coal Tar, Complex Hydrocarbon Mixture

Component CAS-No. [%][US P1/13]

Naphthalene 91-20-3 9.0
1-Methylnaphthalene 90-12-0 2.3
2-Methylnaphthalene 91-57-6 5.1
Indene 95-13-6 0.9
Fluorene 86-73-7 4.2
Acenaphthylene 208-96-8 0.3
Acenaphthene 83-32-9 6.1
Phenanthrene 85-01-8 12.2
Anthracene 120-12-7 2.2
Fluoranthene 206-44-0 6.8
Pyrene 129-00-0 6.0
Benz[a]anthracene 56-55-3 0.5
Chrysene 218-01-9 1.5
Benzo(a)pyrene 50-32-8 0.5

Total of 5 remaining EPA-PAH: ca. 1.4

(Benzo[b]fluoranthene, 205-99-2 0.8
Benzo[k]fluoranthene, 207-08-9 0.3
Indeno[1,2,3-cd]pyrene, 193-39-5 0.1
Dibenzo[a,h]anthracene, 53-70-3 not identified
Benzo[ghi]perylene, 191-24-2 <0.1

Test animals

Species:

rat

Strain:

other: SD, Crl:CD® VAF/Plus®

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Portage, Michigan, USA
- Age at study initiation: Approx. 13 weeks
- Weight at study initiation:210 – 278 g

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

VEHICLE

- Concentration in vehicle: 2.5, 7.5, 22.5 mg/ml
- Amount of vehicle (if gavage):10 ml/(kg bw*d)

Analytical verification of doses or concentrations:

no

Details on mating procedure:

Mating period: Until detection of copulatory plug (= day 0 of gestation)

Duration of treatment / exposure:

Day 6-15 of gestation

Frequency of treatment:

1x/d

Duration of test:

Duration of exposure: Day 6-15 of gestation
Postexposure period: Day 16-20 of gestation.

Doses / concentrations

Remarks:

Doses / Concentrations:
25, 50, 175 mg/(kg bw*d)
Basis:
actual ingested

No. of animals per sex per dose:

30 mated females

Control animals:

yes, concurrent vehicle

Details on study design:

--

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily on days 6-20

BODY WEIGHT: Yes
- Time schedule for examinations: Days 0, 6, 9, 12, 16 and 20

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes, days 0, 6, 9, 12, 16 and 20
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study) No


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Number and location of viable and non-viable fetuses

Fetal examinations:

- External examinations: Yes
- Soft tissue examinations: Yes
- Skeletal examinations: Yes
- Head examinations: No data

Litter size, number of dead foetuses, foetal weight, sex ratio, external alterations

Statistics:

--

Indices:

--

Historical control data:

--

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
175 mg/(kg*d) dosage level: weak maternal toxicity as evidenced by increased hair loss, body weight loss during the first subinterval of treatment (gestation days 6-9), inhibition in body weight gain during the treatment period (days 6-16) and throughout gestation (until day 20), and decreased food consumption. There was a decreasing trend only without clear statistical significance.
50 mg/(kg*d) dosage level or lower: No evidence of maternal toxicity.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

LOAEL

Effect level:

175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Developmental toxicity at the 175 mg/(kg*d) dosage level: Increased incidence in post-implantation loss (including three whole litter resorptions vs. one litter resorbed in the vehicle control and none in the other treated groups), and reduced number of live foetuses. No adverse effect was demonstrated for late intrauterine development of live foetuses at any dose.
No evidence of developmental toxicity was observed at the 50 mg/(kg*d) dosage level or lower.
One, six, seven, and seven foetuses showed malformations in one, three, six, and five litters for the control, low-, mid-, and high-dose groups, respectively. The incidences for the mid-, and high-dose levels were significantly higher than for the control group. Most of the observed malformations are fairly common in rats and the values obtained for the eye malformations in this study were within historical control range. After factoring out these common eye abnormalities, each type of the remaining malformations occurred in only one or two instances per group. Thus, the malformations were not considered to be test-article related.
Developmental variations that occurred did not follow a dose-related pattern.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: embryotoxicity

2

Dose descriptor:

LOAEL

Effect level:

175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: embryotoxicity

3

Dose descriptor:

NOAEL

Effect level:

175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

4

Dose descriptor:

LOAEL

Effect level:

> 175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

5

Dose descriptor:

NOAEL

Effect level:

175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

6

Dose descriptor:

LOAEL

Effect level:

> 175 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Table forMaternal Effects
Parameter	Control data		25   mg/(kg*d)	50 mg/(kg*d)	175 mg/(kg*d)	Dose-response + / –
	historical	study
Number of dams examined	716	30	30	30	30
Pregnant females		27	20	23	23
Pregnancies [%]		90.0	66.0	76.0	76.0	–
Clinical findings during application of test substance		13	15	11	17	–
Mortality of dams [%]	0	0	0	0	0	–
Body weight gain
day 0-6		34	34	32	30	–
day 6-9		2	5	3	-2	–
day 9-12		12	12	13	12	–
day 12-16		28	21	25	21	–
day 16-20		57	65	64	51	–
day 6-16		42	38	40	31	–
day 0-20	143	133	137	136	112	–
Final dam weight change minus weight of uterus	62	64	67	66	61	–
Food consumption [g/animal/day]
day 0-6		21.2	21.0	20.2	20.5	–
day 6-9		14.6	16.7	14.4	12.9	–
day 9-12		14.1	15.5	14.1	13.6	–
day 12-16		17.9	15.0	12.6*	9.8**	+
day 16-20		25.5	28.6	29.5	30.4	–
day 6-16		15.7	15.7	13.6	11.9**	+
day 0-20		19.4	19.9	18.8	18.2	–
Necropsy findings in dams dead before end of test		No deaths occurred before end of test.
* Significantly different from controls, p ≤ 0.05 ** Significantly different from controls, p ≤ 0.01

Table forDevelopmentalEffects Litter response (Caesarean section data)
Parameter	Controldata		25 mg/kg/ day	50 mg/kg/ day	175 mg/kg/ day	Dose-response + / -
	historical	study
Corpora lutea mean/dam	16.8	16.6	16.0	16.3	16.0	–
Implantations mean/dam	15.0	14.2	13.8	14.6	12.9	–
Resorptions total/number of dams	850/708	31/27	17/20*	25/23	59/23*	+
Number of foetuses/dam		13.0	13.0	13.5	10.3	–
Pre-implantation loss [%]		11.6	13.8	10.6	12.2	–
Post-implantation loss [%]	7.3	8.1	6.2	7.4	19.9	+
Total number of litters		26	20	23	20	–
Foetuses / litter		13.0	13.0	13.5	10.3	–
Live foetuses / litter ratio	13.9	13.0	13.0	13.5	10.3	–
Dead foetuses / litter ratio		0	0	0	0	–
Foetus weight (mean) [g]	3.4	3.3	3.5	3.3	3.2	–
Male foetuses		3.4	3.6	3.4	3.3*^1)	+
Female foetuses		3.3	3.3	3.2	3.2	–
Uterine weight (mean) [g]	76.3	72.0	69.5	70.0	61.4	–
Crown-rump length (mean)[mm]		35	36	35	35	–
Foetal sex ratio [state ratio m/f]	0.982	1.108	0.904	1.006	1.135	–
* Significantly different from controls, p ≤ 0.05 ^1)questionable, no effect on crown length, see also female values, considered biologically irrelevant
Table forMorphologicalEffects Examination of the foetuses(Report, Tab. 9 + 10, p. 42/43)
Parameter	Controldata		25 mg/kg/ day	50 mg/kg/ day	175 mg/kg/ day	Dose-response + / -
	historical	study
External malformations^*[%]	0.20	0.00	0.77	2.89^1)	1.27	–
Skeletal malformations^*[%]	0.93	0.00	0.81	4.35^1)	1.72	–
Visceral malformations^*[%]	0.41	0.58	2.21	1.33	2.50	–
Fetuses with malformations [%]*		0.58	3.8	3.9^2)	5.5
External variations^*[%]	0.01	0.00	0.00	0.00	0.00	–
Skeletal variations^*[%]	34.4	36.7	50.4	49.7	43.1	–
Visceral variations^*[%]	1.44	10.5	11.0	7.33	1.67	–

*Figures are not given in the original study but calculated from the number of observations and the number of examined foetuses in the respective category.

¹⁾The relatively high incidences are only determined by an accumulation of 11 different skeletal and external malformations within one foetus from doe No. 56513 (Report, Appendix C, p. 100).

²⁾Because of multi-fold malformations observed in two foetuses (one with 4 and a second with 2 defects), the percentage of the number of animals with malformations is lower than the total percentage of malformations (comp. Report,Appendix C, p. 98ff). Four other foetuses carried only one structural defect as in the other dose groups.