Effects of Weathering on the Toxicity of Three Offshore Australian Crude Oils and a Diesel Fuel to Marine Animals

Abstract

The evaporative weathering properties, chemical composition, and toxicity of three Australian Northwest Shelf crude oils and an Australian diesel fuel were evaluated. The crude oils include one each of a condensate, a light, and a medium crude oil. Between 23 and 100% of the mass of the oils is lost during evaporative weathering equivalent to about 1 week on the sea surface. During weathering, the oils lose most of their monocyclic aromatic hydrocarbons (MAHs) and phenols; concentrations increase of less volatile phenols and polycyclic aromatic hydrocarbons (PAHs). The acute toxicity of water‐accommodated fractions (WAFs) of the fresh and weathered oils to six species of temperate and tropical marine animals ranges from > 100% to about 11% WAF. The MAHs are the most important contributors to the acute toxicity of the WAFs of the fresh oils. The contribution of PAHs to WAF toxicity increases with weathering. About 58% of the hazard indices (HI: exposure concentration/acutely toxic concentration) for the WAFs of the two light oils weathered for the equivalent of 1 d are attributable to PAHs. The toxicity of the WAFs of the condensate and light crude oil can be accounted for by MAHs, PAHs, and phenols; WAFs of the middle‐weight crude oil and diesel fuel are higher than predicted based on their concentrations of total MAHs, PAHs, and phenols, indicating that other components of the WAFs are contributing to their toxicity. These components may include the unresolved complex mixture and polar compounds (resins).

Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance

“…We selected diesel fuel as it is a common contaminant of polar soils, as is jet fuel (Aislabie et al, 2006;Bell et al, 2011;Yergeau et al, 2012c), which is similar in composition to diesel. Soils were incubated for 1 week at 1 1C to allow abiotic loss of the volatile components of diesel, as most short-term evaporative weathering can occur within 1 week of contamination (Neff et al, 2000). Following weathering, a 50-g sample was removed to determine baseline hydrocarbon concentrations.…”

Haematological changes associated with crude oil ingestion in experimental rabbits

“…Crude petroleum was obtained from the Nigerian Agip Oil Company Ltd and exposed to sunlight in shallow pans (30 cm x 30 cm x 5 cm) for 24 h at the venue of the project to allow the extremely light and volatile fractions to evaporate leaving behind the stable components. This product simulates the naturally occurring condition following spillage (Neff et al, 2000). Animals were starved for 24 h before being fed the experimental diets.…”

Biochemical and Enzyme Responses in Rabbits Experimentally Fed Crude Oil Contaminated Diets

“…Crude oil was obtained from the Nigerian Agip Oil Company Ltd. and exposed for 24h in shallow pans to sunlight so that the volatile fractions could vaporize thus simulating the naturally occurring fraction following spillage (Neff et al, 2000). Measured amounts of crude oil was incorporated into the forage and poultry mash by simple mixing and homogenization with a manual mixer.…”