Extracts (petroleum), heavy paraffinic distillates, solvent-deasphalted

Endpoint summary

Additional information

Treated distillate aromatic extracts (TDAEs) are a further processing of distillate aromatic extracts (DAEs) in an attempt to reduce the amount of 3-7 ring PAC that is present. Since the treatment is mostly a selective reduction of PACs, the data from DAEs can serve as read across where treatment was insufficient and a significant amount of PACs still remain (≥ 3 wt% DMSO extractables as measured by IP-346). Where treatment was sufficient to reduce the 3-7 ring PACs (<3 wt% DMSO extractables as measured by IP-346), the material is most similar to a lubricating base oil and it is this data that should be used for read across. 

TDAEs (IP 346 ≥ 3 wt%)

 

In a read-across bioavailability toxicokinetics study in pregnant rats, three doses of 1000 mg/kg of radiolabelled 318 isthmus furfural extract (a distillate aromatic extract) was dermally administered on gestation days 10, 11, and 12 (Mobil 1989, Klimisch score = 4). Maternal tissues, blood, placentas, uteri, embryos, and yolk sacs were collected and analyzed for radioactivity on gestation day 13 following sacrifice. Urine, faeces, and cage wash was collected every 24 hours and also analyzed for radioactivity.

 

Dermal absorption of 14C-carbazole occurred more extensively than did 3H-benzo(a)pyrene over a 72 hour period. About 19.9% and 4.1% of the total applied of 14C-carbazole and 3H-benzo(a)pyrene, respectively, was dermally absorbed. Of the total absorbed dose of 14-C-carbazole, 2.1% was found in the maternal tissues and less than 0.01% was detected in the embryo. Of the total absorbed dose of 3H-benzo(a)pyrene 1.8% was detected in the maternal tissue and less than 0.01% was found in the embryo. 17.7% of 14C-carbazole was excreted in the urine and faeces over 72 hours. 2.3% of 3Hbenzo(a)pyrene was excreted in the urine and faeces over 72 hours.

 

Based on the bioavailability results, neither of the radiolabelled components of 318 isthmus furfural extract were found to selectively accumulate in the embryo.

Mutagenicity and carcinogenicity of a series of 39 petroleum oils, including several DAEs, were correlated with the content of 3-7 ring PACs. Further, the steady-state dermal penetration of PAC in long-term testing was also determined predominantly by PAC concentration. Although aromaticity and viscosity had a minimal effect on dermal penetration, neither was an important determinant of the carcinogenic potency.

 

Substances in this category are UVCBs; hence it is not possible to apply standard methodology for assessing absorption, distribution and metabolism. Relevant data for use in risk assessment are available for constituent compounds.

TDAEs (IP 346 < 3 wt%)

In a basic toxicokinetic study performed by Baldwin et al., (1992) hydrotreated treated white oil was mixed with the diet of male and female rats in concentrations of 0, 10, 100, 500, 1000, 5000, 10000, and 20000 ppm for a period of 13 weeks. After sacrifice, haematological, clinical chemistry, gross necropsy, tissue residue, and histopathological examinations were preformed. There were no mortalities or adverse effects associated with feeding the rats oleum-treated white oil. Treatment related effects were generally dose-related and more marked in females than in males. After 90 days of treatment moderate multifocal granulomatous changes in mesenteric lymph nodes and liver were observed. Oleum-treated oil caused a greater pathological response then hydrotreated white oil. The hydrotreated white oil (applicable to sufficiently refined hydrocarbons, IP 346 < 3%) is metabolized to the corresponding fatty acids of the same carbon chain length as the parent carbons, suggesting omega oxidation.

A toxicokinetics study performed by Albro et al. (1970) evaluated absorption of hydrocarbon mixtures (IP 346 <3%). Simple mixtures of aliphatic hydrocarbons were administered to rats by gastric intubation at dose levels of up to 500 mg/kg b.w. The percentage retention of the aliphatic hydrocarbons was inversely proportional to the number of carbon atoms and ranged from 60% for C₁₄to 5% for C₂₈compounds. The major site of absorption was found to be the small intestine.

A toxicokinetics study performed by Ebert et al. (1966) evaluated distribution of tritiated mineral oil (IP 346 <3%) administered orally and via i.p. injections. Male and female rats were dosed with 0.66 mL of radiolabelled mineral oil for thirty-one consecutive days. Radioactivity was measured in extracted tissues after sacrifice. Urine and faeces were collected and stored daily for radioactivity analysis. Results indicate that radioactivity is primarily found in liver, fat, kidney, brain, and spleen. Eighty percent of the tritiated mineral oil administered orally was not absorbed but rather excreted in the faeces two days after treatment. Only 11% of the total dose administered by i.p. injection was excreted in the faeces during the first 8 days of the study. About 8% of the radioactivity administered orally and via intraperitoneal injection was excreted in the urine during the week following drug administration. Both oral and i.p. routes of administration exhibited the same characteristics of absorption.