The relationship between repeat-dose toxicity and aromatic-ring class profile of high-boiling petroleum substances

Herron²,

Beatty

et al. 2013

Green petroleum coke is primarily inorganic carbon with some entrained volatile hydrocarbon material. As part of the petroleum industry response to the high production volume challenge program, the potential for reproductive effects was assessed in a subchronic toxicity/reproductive toxicity screening test in rats (OECD 421). The repeated-dose portion of the study provided evidence for dust accumulation and inflammatory responses in rats exposed to 100 and 300 mg/m 3 but there were no effects at 30 mg/m 3 . In the reproductive toxicity screen, the frequency of successful matings was reduced in the high exposure group (300 mg/m 3 ) and was not significantly different from control values but was outside the historical experience of the laboratory. The postnatal observations (external macroscopic examination, body weight, and survival) did not indicate any treatment-related differences. Additional tests conducted to assess the potential hazards to aquatic (fish, invertebrates, and algae) and soil dwelling organisms (earthworms and vascular plants) showed few effects at the maximum loading rates of 1000 mg coke/L in aquatic studies and 1000 mg coke/kg soil in terrestrial studies. The only statistically significant finding was an inhibition of algal growth measured as either biomass or growth rate.

Section: Discussioncontrasting

confidence: 53%

Toxicological Assessment of Green Petroleum Coke

Herron²,

Beatty

et al. 2013

“…The predictions were based on a series of statistically developed empirical models. [15][16][17] Each sample was characterized by the dose associated with a 10% change in the control group response, identified as the ''predicted dose response at 10% (PDR 10 ).'' The PDR 10 is similar in concept to the benchmark dose (BMD 10 ).…”

Section: Predictions Of Systemic and Developmental Toxicitymentioning

confidence: 99%

“…Because of the large number of crude oils, testing all possible substances is not practical. Rather, a series of empirical statistical models 15 was developed by which it was possible to predict the likelihood of systemic 17 and developmental 16 toxicity based on ARC profiles. Two crude oils that have been tested for repeated dose and developmental toxicity by dermal administration were available for comparison.…”

Section: Smentioning

confidence: 99%

Use of a Statistical Model to Predict the Potential for Repeated Dose and Developmental Toxicity of Dermally Administered Crude Oil and Relation to Reproductive Toxicity

Nicolich²,

Roy

et al. 2013

Petroleum (commonly called crude oil) is a complex substance primarily composed of hydrocarbon constituents. Based on the results of previous toxicological studies as well as occupational experience, the principal acute toxicological hazards are those associated with exposure by inhalation to volatile hydrocarbon constituents and hydrogen sulfide, and chronic hazards are associated with inhalation exposure to benzene and dermal exposure to polycyclic aromatic compounds. The current assessment was an attempt to characterize the potential for repeated dose and/or developmental effects of crude oils following dermal exposures and to generalize the conclusions across a broad range of crude oils from different sources. Statistical models were used to predict the potential for repeated dose and developmental toxicity from compositional information. The model predictions indicated that the empirical data from previously tested crude oils approximated a ''worst case'' situation, and that the data from previously tested crude oils could be used as a reasonable basis for characterizing the repeated dose and developmental toxicological hazards of crude oils in general.

“…Recently developed statistical models provide a means of predicting the outcomes of repeated dose and developmental toxicity tests from the distribution of aromatic constituents in these substances. [17][18][19] Samples of HFO substances and other high-boiling materials were supplied by petroleum companies for chemical analysis of polycyclic aromatic content by ring distribution. Statistical models were developed using toxicology data from a wide range of high-boiling petroleum substances to predict doses at which there is a 10% change in response (predicted dose response [PDR] 10) for sensitive end points.…”

Section: International Journal Of Toxicology 33(supplement 1)mentioning

confidence: 99%

“…[17][18][19] It should be noted, however, that the models are empirical and not defined in terms of specific constituents. [17][18][19] Hoberman et al 20 reported that dermal application of another sample of CCCO resulted in significantly reduced uterine weights and offspring body weights and increased frequencies of dead or resorbed conceptuses at levels as low as 1 mg/kg/d. However, the same test substance had no effects on reproductive parameters when tested at levels as high as 250 mg/kg/d.…”

Section: Introductionmentioning

confidence: 99%

The Toxicological Effects of Heavy Fuel Oil Category Substances

Reitman

Schreiner³

et al. 2013

Heavy fuel oil (HFO) category substances are used to manufacture HFO, a product used in industrial boilers and marine diesel engines. Commercial HFOs and blending stream components are substances of complex and variable composition, composed of C 20 to >C 50 hydrocarbons, although lower molecular weight material may be added to reduce viscosity and improve flow characteristics. An HFO blending stream (catalytically cracked clarified oil [CCCO]) was tested for target organ and developmental toxicity in rats following repeated dermal administration at doses of 5, 25, or 50 mg/kg/d. In the repeated dose study, there was evidence of increased liver weights, reduced thymus weights, and reductions in hematological parameters with an overall no observed adverse effect level (NOAEL) of 5 mg/kg/d. In the developmental toxicity test, there were significant reductions in fetal survival, significant increases in resorption frequency, and significantly reduced fetal weights with an overall NOAEL of 5 mg/kg/d. These target organ and developmental effects are associated with the types and levels of aromatic constituents in these substances. Among HFO blending streams, CCCOs have the highest levels of aromatics and, because they produce the characteristic toxicological effects at the lowest levels, are considered as ''reasonable worst-case examples'' for this group of substances. Other HFO category members with lower levels of aromatics produce similar effects but have higher NOAELs. The potential for target organ and developmental effects of other HFO category members can be predicted from information on the types and levels of the aromatic constituents present in these substances.