An evaluation of the acute toxic properties of liquids derived from oil sands

Abstract

The acute toxicity of three materials derived from Athabasca Oil Sands--(1) bitumen plus naphtha, (2) untreated naphtha (0-250 degrees C) and (3) synthetic crude oil (0-500 degrees C)--was assessed in a battery of tests. In acute oral studies, all three test materials exhibited a low order of toxicity (LD50 greater than 5.0 g kg-1). The acute dermal LD50 was also low (greater than 3 g kg-1) for each test material. All three materials were judged to be 'slight' ocular irritants. Acute inhalation studies (6-h exposures at the maximum attainable concentrations) produced varied responses. Bitumen plus naphtha administered at a concentration of 1.46 mg l-1 did not cause mortality in exposed rats or mice. Lung discoloration was the only necropsy finding of note. Untreated naphtha administered at a concentration of 10.6 mg l-1 was lethal to essentially all of the mice; but only two rats died. Necropsy findings included elevated weights in the liver and kidneys of the exposed mice, elevated lung weights in male rats and elevated liver weights in female rats. Synthetic crude oil administered at a concentration of (4 mg l-1) was lethal to 5/10 mice, but none of the rats (0/10) died. Severe hair loss was noted in the surviving mice, and slight alopecia was also observed in rats. Both species exhibited elevated liver weight, and elevated lung weight was noted in female rats.

Acute and Subchronic Toxicity of Naturally Weathered Exxon Valdez Crude Oil in Mallards and Ferrets

“…Liver enlargement was noted in male birds. This was not unexpected, as similar findings have been noted in both mammalian [26,27] and avian [4,23,28] species when exposed for similar or longer time periods to a variety of hydrocarbon materials, including unweathered Prudhoe Bay crude oil [29]. The lack of abnormal clinical parameters for characteristic liver enzymes (i.e., ALT and AST) coupled with the absence of abnormal findings during microscopic examination suggests that this was a compensatory mechanism (rather than a toxic effect) to cope with the increased metabolic demands associated with the metabolism and elimination of hydrocarbons [29].…”

Acute and subchronic toxicity of naturally weathered Exxon valdez crude oil in mallards and ferrets

“…Liver enlargement was noted in male birds. This was not unexpected, as similar findings have been noted in both mammalian [26,27] and avian [4,23,28] species when exposed for similar or longer time periods to a variety of hydrocarbon materials, including unweathered Prudhoe Bay crude oil [29]. The lack of abnormal clinical parameters for characteristic liver enzymes (i.e., ALT and AST) coupled with the absence of abnormal findings during microscopic examination suggests that this was a compensatory mechanism (rather than a toxic effect) to cope with the increased metabolic demands associated with the metabolism and elimination of hydrocarbons [29].…”

Consequences of oil spills: a review and framework for informing planning

“…Bitumen is a product of tar sands and the heaviest form of crude oil produced (Stubblefield et al 1989, Masliyah et al 2004, Upreti et al 2007). Because of its high density, bitumen is first diluted to facilitate transportation through pipelines.…”

“…Because of its high density, bitumen is first diluted to facilitate transportation through pipelines. Although the exact chemical composition of the diluted bitumen being shipped through the port of Vancouver is a trade secret, diluents are commonly volatile organic compounds (VOCs), which are toxic to wildlife and humans (Stubblefield et al 1989, Upreti et al 2007). …”

“…Temperature and salinity influence solubility of oil, rates of oil degradation and effectiveness of oil dispersants Whitehouse 1984;Blondina et al 1999;Chandrasekar et al 2006 Substrate at site exposed to oil Exposure to toxins Heavy crude oil products are often diluted with toxic chemicals, posing an additional hazard e.g., Stubblefield et al 1989;Upreti et al 2007 Exposure quantity Increased oil exposure increases initial injury as well as recovery time (usually non-linearly) Silliman et al 2012 Habitat/ depth of species Subsurface species will have reduced exposure to oil (assuming that the majority of the oil does not sink), while species near the surface and in intertidal zones will have the highest exposure to oil Mobility Highly mobile species may be able to move away from spill areas, reducing their exposure, while sedentary species are not…”