Aquatic hazard and biodegradability of light and middle atmospheric distillate petroleum streams

Abstract

Light and middle atmospheric distillate petroleum substances are blended to produce fuels used in transportation and heating. These substances represent the majority by volume of crude oil refined products in the United States. The goal of this research was to develop biodegradability and aquatic toxicity data for four substances; heavy, straight-run naphtha (HSRN), hydro-desulfurized kerosene (HDK), hydro-cracked gas oil (HCGO), and catalytic-cracked gas oil (CCGO). Ready biodegradability tests demonstrated rapid and extensive microbial oxidation of these test substances, indicating a lack of persistence in the aquatic environment. Differences in biodegradation patterns reflected compositional differences in the constituent hydrocarbons. Results of aquatic toxicity tests on alga, cladocera, and fish demonstrated that toxicity was greatest for catalytic-cracked gas oil, which contained a high proportion of aromatic hydrocarbons. Aromatic hydrocarbons are more soluble, and hence more bioavailable, resulting in higher toxicity. When expressed on the basis of loading rates, acute toxicity values (LL/EL50) ranged between 0.3 and 5.5 mg L(-1) for all three species, while chronic no-observed-effect loading rates (NOELR) ranged between 0.05 and 0.64 mg L(-1). PETROTOX estimates for acute and chronic toxicity ranged from 0.18 to 2.3 mg L(-1) and 0.06 to 0.14 mg L(-1), respectively, which were generally more conservative than experimental data.

Oil Spill Dispersants: Boon or Bane?

“…Only acute toxicity tests are required for listing under the National Contingency Plan, but of course chronic effects are also a real concern. As expected, the longer exposure required to see chronic effects allows lower concentrations of hydrocarbons to exert an effect, and typical acute-to-chronic ratios are 1:10, that is, it may only take 10% of the acute LC 50 to have a chronic EC 50 . − Again, these concentrations are for prolonged exposures, and it is not clear how these relate to the very low concentrations − of dispersed oil that are found several days after dispersion …”

Fire Suppression Agents Combined with Gasoline in Aquatic Ecosystems: A Mixture Approach

“…The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (1993) stated that a level of oil and grease as low as 0.01 mg L −1 in marine water would be necessary for protection of the biota. Based on toxicity tests with algae, cladocerans, and fish, Swigert et al (2014) observed that chronic no-observed-effect loading rates ranged between 0.05 and 0.64 mg L −1 . Carls and Meador (2009), in a review on the toxicity of petrogenic PAHs to fish embryos, stated that the toxic threshold should be 0.5 µg L −1 or lower.…”

Evaluating the primary and ready biodegradability of dianilinodithiophosphoric acid

“…Previous studies argued the pass levels for readily biodegradability and agreed that the 10-day time window criterion is justified and useful (Mei et al 2015;Pedrazzani et al 2012;Reuschenbach et al 2003;Swigert et al 2014). Figure 6 shows the degradation rate of DDA and sodium oleate and the start time of the 10-day window, if present.…”