To characterize the toxicological hazards of petroleum gases, 90-day inhalation toxicity (Organization for Economic Cooperation and Development [OECD] 413) and developmental toxicity (OECD 414) tests were conducted with liquefied propane gas (LPG) at concentrations of 1000, 5000, or 10 000 ppm. A micronucleus test (OECD 474) of LPG was also conducted. No systemic or developmental effects were observed; the overall no observed adverse effect concentration (NOAEC) was 10 000 ppm. Further, there was no effect of LPG exposure at levels up to 10 000 ppm on micronucleus induction and no evidence of bone marrow toxicity. Other alkane gases (ethane, propane, n-butane, and isobutane) were then evaluated in combined repeated exposure studies with reproduction/development toxicity screening tests (OECD 422). There were no toxicologically important changes in parameters relating to systemic toxicity or neurotoxicity for any of these gases at concentrations ranging from 9000 to 16 000 ppm. There was no evidence of effects on developmental or reproductive toxicity in the studies of ethane, propane, or n-butane at the highest concentrations tested. However, there was a reduction in mating in the high-exposure group (9000 ppm) of the isobutane study, which although not significantly different was outside the range previously observed in the testing laboratory. Assuming the reduction in mating to have been toxicologically significant, the NOAEC for the isobutane reproductive toxicity screening test was 3000 ppm (7125 mg/m 3 ). A method is proposed by which the toxicity of any of the 106 complex petroleum gas streams can be estimated from its composition.
This study examined the effects of an adapted alternating treatments design (AATD) consisting of teacher-facilitated and iPad-facilitated instruction on at-risk preschool children’s vocabulary. Instruction was provided on 42 verbs, divided equally between treatments, across five participants over the course of 7 weeks. Dependent variables included expressive (i.e., providing a definition) and receptive (i.e., identifying the target verb from a picture menu, and yes/no questions including correct and incorrect definitions of the verb) probes of instructional targets. All five participants demonstrated increases from pretest to posttest in their expressive and receptive understanding of the verbs. Implications for research and practice are provided.
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.
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