Extracts (petroleum), heavy paraffinic distillate solvent

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Effects on reproductive organs were examined in a 90-day dermal study in rats and a 90-day oral study.  Detailed results of these studies are presented in the repeated dose toxicity section.  Histopathological changes in the reproductive organs or sperm morphology counts were not observed in the dermal study ; however they were observed in the oral study.

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In the key developmental toxicity study (WIL Research, 2012) the light paraffinic distillate solvent (CAS 64742-05-8) administered to rats caused maternal toxicity in the 25, 150, and 450 mg/kg/day groups that manifested with adverse clinical and/or macroscopic findings and a higher incidence of dermal observations at these exposure levels. The increased mean litter proportions of postimplantation loss (primarily early resorptions) with corresponding decreases in the mean numbers and litter proportions of viable foetuses were also noted. Number of test- substance-related skeletal developmental variations were demonstrated including reduced ossification of the skull, reduced ossification of the vertebral arches, and sternebra[e] nos.

According to supporting study of Mobil (1989), implantation was not affected by treatment in a DAE developmental toxicity study by dermal application in rats at doses of 0, 30, 125 (gestation days 0–19) 500 mg/kg (gestation days 0–16), or 1000 mg/kg (gestation days 10-12). The number of dams with no viable offspring was increased at 125 and 500 mg/kg, but not at 1000 mg/kg for the shorter exposure duration.

Short description of key information:

In the key developmental toxicity study (OECD 414), the light paraffinic distillate solvent administered to rats caused maternal and developmental toxicity. An increased mean litter proportions of postimplantation loss with corresponding decreases in the mean numbers and litter proportions of viable foetuses as well as number of test- substance-related skeletal developmental variations were noted.

The supporting developmental toxicity study (OECD 414) performed on 318 isthmus furfural extract reported that implantation was not affectedby dermal treatment of rats up to dose levels of 1000 mg/kg/day.

Justification for selection of Effect on fertility via oral route:

DAEs are classified as Category 1B carcinogens

Justification for selection of Effect on fertility via inhalation route:

DAEs are classified as Category 1B carcinogens

Justification for selection of Effect on fertility via dermal route:

DAEs are classified as Category 1B carcinogens

Effects on developmental toxicity

Description of key information

One key development study (OECD 414) was identified. In this study, light paraffinic distillate solvent (CAS 64742-05-8) extract produced maternal, reproductive and foetal toxicity. Maternal toxicity was evident in the 25, 150, and 450 mg/kg/day groups with adverse clinical and/or macroscopic findings and a higher incidence of dermal observations at these exposure levels. Mean thymus weights (absolute and relative to brain) were noted in the 25, 150, and 450 mg/kg/day groups. No evidence of maternal toxicity was noted at 5 mg/kg/day. The light paraffinic distillate solvent extract was developmentally toxic at the concentrations of 150 and 450 mg/kg/day. increased mean litter proportions of postimplantation loss (primarily early resorptions) with corresponding decreases in the mean numbers and litter proportions of viable foetuses. Number of test- substance-related skeletal developmental variations were also observed including reduced ossification of the skull, reduced ossification of the vertebral arches, and sternebra[e] nos.

Other development study (OECD 414) (Mobil, 1989, supporting study) demonstrated that heavy paraffinic distillate aromatic extract produced maternal, reproductive and foetal toxicity. Maternal toxicity was exhibited as vaginal discharge (dose-related), body weight decrease, reduction in thymus weight and increase in liver weight (125 mg/kg/day and higher) and aberrant haematology and serum chemistry (125 and/or 500 mg/kg/day). Evidence of potential reproductive effects was shown by an increased number of dams with resorptions and intrauterine death. DAE was developmentally toxic as indicated by increased resorptions and decreased foetal body weights. Furthermore, when exposures were increased to 1000 mg/kg/day and given only during gestation days 10 through 12, cleft palate and ossification delays were observed. Cleft palate was considered to indicate a potential teratogenic effect of DAE.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

125 mg/kg bw/day

Species:

rat

Quality of whole database:

research study to identify sensitive gestation time

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

5 mg/kg bw/day

Study duration:

subacute

Species:

rat

Additional information

In the developmental toxicity study (WIL Research, 2012, key study), Sprague-Dawley rats were exposed dermally to the light paraffinic distillate solvent (CAS 64742-05-8) extract during gestation days 0 to 19 for developmental effects and maternal toxicity. The following doses:5, 25, 150 and 450 mg/kg/day were administered once per day to rats (25 animals per group).

Maternal toxicity was evident at 25, 150, and 450 mg/kg/day as noted by clinical findings (yellow and/or red material on the urogenital area, red vaginal discharge, body pale and/or cool to the touch) at the daily examinations and/or 1 to 2 hours following dose administration and dermal observations of desquamation. One and 3 females in the 150 and 450 mg/kg/day groups, respectively, were euthanized in extremis between gestation days 14-18 as a result of lower mean food consumption with corresponding mean body weight losses and/or lower mean body weight gains noted in these groups generally throughout the treatment period; differences were generally statistically significant. Decreased mean food consumption with corresponding decrements in mean body weight gain were noted in the latter part of gestation in the 25 mg/kg/day group and correlated with the lower mean fetal weights noted in this group. Test substance-related macroscopic findings noted in the 150 and 450 mg/kg/day groups included dark red contents in the uterus, vagina, and/or cervix. Additionally, small thymus was noted at these exposure levels and corresponded to the statistically significantly lower mean thymus weights (absolute and relative to brain) noted in the 150 and 450 mg/kg/day groups. Statistically significantly lower mean thymus weights (absolute and relative to brain) were also noted in the 25 mg/kg/day group.

Developmental toxicity was evident at 25, 150, and 450 mg/kg/day. Increased mean litter proportions of postimplantation loss (primarily early resorptions) with corresponding decreases in the mean numbers and litter proportions of viable fetuses were noted at 150 and 450 mg/kg/day. With the exception of 1 female that had 3 viable fetuses, all surviving females in the 450 mg/kg/day group had entirely resorbed litters (100% postimplantation loss with 0.0% viable fetuses). Therefore, comparative statistics were not performed on the mean fetal weights at 450 mg/kg/day. However, the fetal weights for the single litter in the 450 mg/kg/day group were lower than the vehicle control group. Additionally, mean male, female, and combined fetal weights in the 25 and 150 mg/kg/day groups were statistically significantly lower than the vehicle control group. These differences resulted in lower mean gravid uterine weights in the 25, 150, and 450 mg/kg/day groups; differences were statistically significant at 150 and 450 mg/kg/day. Test substance-related skeletal developmental variations (sternebra[e] nos. 5 and/or 6 unossified, reduced ossification of the skull, reduced ossification of the vertebral arches, and sternebra[e] nos. 1, 2, 3, and/or 4 unossified, and cervical centrum no.1 ossified) were noted in the 150 mg/kg/day group. The findings of sternebra(e) nos. 5 and/or 6 unossified, reduced ossification of the skull, and sternebra(e) nos. 1, 2, 3, and/or 4 unossified were also noted for fetuses in the single surviving litter at 450 mg/kg/day. The aforementioned findings were considered indicators of developmental delay and correlated to the reduced fetal weights noted at 150 and 450 mg/kg/day.

Based on these results, an exposure level of 5 mg/kg/day was considered to be the no-observed-adverse-effect level (NOAEL) for maternal toxicity and embryo/fetal development when extract, light paraffinic distillate solvent was administered by dermal application to bred Crl:CD(SD) rats.

In a developmental study of Mobil (1989, supporting study) study with heavy paraffinic DAE (CAS number 64742 -04 -7), 318 Isthmus Furfural Extract, was tested in a dermal study during gestation days 0 to 19 for developmental effects and maternal toxicity in the Sprague-Dawley rat.

Nine groups of pregnant rats were divided in three groups: prenatal, postnatal and bioavailability groups. These groups are further described below. Bioavailability group procedures and results are described separately.

Prenatal groups: the undiluted test sample was applied without occlusion to the shaved skin of pregnant rats at doses of 8, 30, and 125 mg/kg/day on gestation days 0-19 (15/group). An additional group received the same treatment at 500 mg/kg/day on gestation days 0 through 16. Initially, administration of the test sample to the 500 mg/kg/day group was also scheduled for gestation days 0 through 19, however treatment was discontinued after gestation day 16 because a high incidence of resorption was suspected (as indicated by a red vaginal discharge observed among rats in this group). Another prenatal group received the same treatment at 1000 mg/kg/day only on gestation days 10 through 12, an interval at which the developing foetus is sensitive to teratogenic insult. A group of sham treated rats served as control. Prenatal groups were sacrificed on gestation day 20.

The postnatal group was exposed under the same conditions as the prenatal group. Postnatal animals (10/group) were dosed at 0 or 125 mg/kg/day on gestation days 0 through 19. Postnatal groups were allowed to deliver their offspring naturally. Pups were observed on post partum day 0 for external malformations and variations and then together with their dams, sacrificed on post partum day 4.

End points examined in adults included clinical signs (all groups except bioavailability group) body weight (all groups), food consumption (all groups except bioavailability group), haematology and serum chemistry (only prenatal groups), liver and thymus weights (all groups except bioavailability group), and uterine and net body weights (all groups except bioavailability group). Foetal toxicity examinations included: resorption incidences, anomalous development (gross, skeletal and visceral abnormalities) and body weight.

Results - Prenatal Group 

Prenatal groups were sacrificed on gestation day 20. All mothers were necropsied and grossly examined. Uterus and ovaries were excised and examined grossly. Numbers of corporea lutea per ovary of each pregnant animal were counted. Ovaries of non-pregnant animals were grossly examined and then discarded. Number and location of implantations, early and late resorptions and live and dead foetuses were recorded.

Maternal toxicity: Red vaginal discharge was observed in a number of pregnant animals in all untreated DAE-exposed groups. Although authors mentioned this as being dose related, no statistics are provided.

In general animals exposed at 125 and 500 mg/kg consumed less food; at this dose level significant reduction in body weight gain, net body weight gain, and gravid uterine weight occurred throughout gestation. Body weight gain was also decreased at dose level of 1000 mg/kg/day. Of the haematology parameters evaluated, platelet and white blood cell counts were significantly affected in a dose related manner. Effects on 14 of 22 analyzed serum components were noted at the 125 or/and 500 mg/kg/day dose levels.

Thymus weights were significantly reduced and liver weights increased at doses in excess of 30 mg/kg/day. 

Reproductive effects: Implantation was not adversely affected by treatment. The number of dams with no viable offspring was increased at dose levels from 125 mg/kg/day. Litter size was significantly lower and resorptions were significantly increased compared to controls at 125 mg/kg/day and higher.

Foetal toxicity and development: At 30 mg/kg/day, although not statistically significant, a twofold increase over controls in the number of resorptions was observed, which the authors considered as of biological relevance. However, reanalysis of the data using the litter as the statistical unit (rather than individual resorptions) identifies 30 mg/kg bw/day as the appropriate NOAEL for developmental toxicity. Treatment at 125 mg/kg/day and at higher doses resulted in decreased mean foetal body weights. A statistically significant increase in the incidence of incompletely ossified skull bones in foetuses exposed in utero to 125 mg/kg/day was observed. 

When the period of exposure was restricted to gestation days 10 through 12 and the dose increased to 1000 mg/kg, defects in costal cartilage development were significantly increased. Two of 114 foetuses evaluated were oedematous and had cleft palates. The cleft palate finding was considered by the authors to be biologically significant and evidence of a teratogenic effect, basis very low historical control incidences at theirs and other laboratories.

Results - Postnatal Group

In the postnatal group (10/group), three females were found to be not pregnant, five females resorbed their entire litters and one dam had only two pups, which she subsequently cannibalised. The postpartum analysis of the single viable litter of this group was not meaningful. 

Results - Bioavailability Group

The bioavailability group included 3 females which were dosed with14C-carbazole- and3H benzo[a]-pyrene [BaP] - labelled DAE at 1000/kg/day on gestation days 10 through 12 and were treated under the same conditions as the previous two groups. Animals were housed in metabolic cages until sacrifice; urine and faeces were collected.

Bioavailability group animals were sacrificed on gestation day 13. Maternal tissues collected for radioactivity measurements were: blood, thymus, liver, small intestine, large intestine, kidneys, stomach and ovaries. Placentas, embryos, amniotic fluid and yolk sacs were pooled for each dam before analysis of radioactivity.

Bioavailability analyses revealed that dermal absorption of both radiolabelled substrates occurred.14C-carbazole was more extensively absorbed than3H-BaP over a 72-hour period (20% and 4% of the original dose respectively after three applications). After 72 hours, about 2% of14C-carbazole and3H-BaP (2.1% and 1.8% respectively) was found in the maternal tissues, primarily in blood, large and small intestines. By comparison, less than 0.01% of each surrogate was detected in the embryo, indicating that3H-benzo[a]-pyrene and14C carbazole do not selectively accumulate in the embryo under conditions of this study. 

The authors concluded that under study conditions heavy paraffinic distillate furfural extract produced maternal, reproductive and foetal toxicity. Maternal toxicity was exhibited as vaginal discharge (dose-related), body weight decrease, reduction in thymus weight and increase in liver weight (125 mg/kg/day and higher) and aberrant haematology and serum chemistry (125 and/or 500 mg/kg/day). Evidence of potential reproductive effects was shown by an increased number of dams with resorptions and intrauterine death. DAE was developmentally toxic as indicated by increased resorptions and decreased foetal body weights. Furthermore, when exposures were increased to 1000 mg/kg/day and given only during gestation days 10 through 12, cleft palate and ossification delays were observed. Cleft palate was considered to indicate a potential teratogenic effect of DAE.

Additional data supports that DAE is a developmental toxicant (Feuston and Mackerer, 1996). This information is presented in the dossier.

Toxicity to reproduction: other studies

Additional information

No DAE fertility studies were located; however, no histopathologic changes were noted in the reproductive organs of male or female rats exposed dermally in a 13-week subchronic test. Further, neither epididymal spermatozoa morphology and count nor testicular spermatid counts were affected by DAE treatments.

A two generational reproductive study to examine the effects of distillate aromatic extracts on fertility does not need to be conducted since the substance is a known carcinogen and appropriate risk management measures are implemented. Distillate aromatic extracts are classified as Category 1B carcinogens according to EU CLP criteria.

Justification for classification or non-classification

No two -generation reproductive toxicity data are available for DAEs. A key developmental toxicity study was conducted on DAE and produced maternal, reproductive and foetal toxicity in rats when administered dermally at doses up to 125 mg/kg/day. The NOAEL for reproductive and developmental toxicity was 30 mg/kg/day. Based on the study results, DAEs are classified as Reproductive Toxicants Category 2 (H361d) according to the EU CLP Regulation (EC No. 1272/2008).