Toxicity of petroleum hydrocarbon distillates to soil organisms

Abstract

Canadian standards for petroleum hydrocarbons in soil are based on four distillate ranges (F1, C6-C10; F2, >C10-C16; F3, >C16-C34; and F4, >C34). Concerns have arisen that the ecological soil contact standards for F3 may be overly conservative. Oil distillates were prepared and characterized, and the toxicity of F3 and two subfractions, F3a (>C16-C23) and F3b (>C23-C34), to earthworms (Eisenia andrei), springtails (Orthonychiurus folsomi), and northern wheatgrass (Elymus lanceolatus), as well as the toxicity of F2 to earthworms, was determined. Clean soil was spiked with individual distillates and measured concentrations were determined for select tests. Results agree with previous studies with these distillates. Reported toxicities of crude and petroleum products to invertebrates were generally comparable to that of F3 and F3a. The decreasing order of toxicity was F3a > F3 > F3b with invertebrates, and F3a > F3b > F3 with plants. The toxicities of F3a and F3b were not sufficiently different to recommend regulating hydrocarbons based on these distillate ranges. The results also suggest that test durations may be insufficient for determining toxicity of higher distillate ranges, and that the selection of species and endpoints may significantly affect interpretation of toxicity test results.

Evaluation of a new battery of toxicity tests for boreal forest soils: Assessment of the impact of hydrocarbons and salts

“…Plant toxicity varied with species and endpoint; however, C. canadensis and P. tremuloides were generally more sensitive to the hydrocarbon-impacted soils, all plants considered. However, consistent with other studies [36,37], greater sensitivity was demonstrated by soil invertebrate sublethal endpoints, relative to plant endpoints. Even though test durations were extended for the boreal species to accommodate for their growth rate, differences in toxicity because of test duration was likely not a major contributing factor, because in some cases test endpoints for the boreal plants (e.g., P. banksiana 35-d test) were less sensitive than the standard test species.…”

Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants

“…Overall the least sensitive endpoint was germination, and the most sensitive endpoint was root growth, but this varied between root and shoot growth depending on the species and the soil type tested (Figure 2, Table 5). Other studies have also shown that germination success is a less sensitive endpoint than root and shoot growth, resulting in an underestimation of the toxicity of fuel-contaminated soils [36,40]. Interestingly for D. chapmanii and E. pendunculare, the order of sensitivity of endpoints was conserved between soil types, but this order differed between soil types for L. crinita and C. muscoides (Table 4).…”

“…During hydrocarbon exposures, acute toxicity is likely caused by lighter, more volatile hydrocarbons with a lower equivalent carbon number; heavy fractions with a high equivalent carbon number are more likely to cause chronic toxic effects [34][35][36][37]. Toxicity of petroleum hydrocarbons is strongly correlated with hydrocarbon fractions that have lower boiling points and octanol-water coefficients [log(K ow )], especially those within the nC10-nC19 range [12,[37][38].…”

Extracellular Electron Transfer in in situ Petroleum Hydrocarbon Bioremediation

“…Saturated and unsaturated structures composed of hydrogen and carbon make up the largest fraction of organic compounds derived from fossil sources, including crude oil, its derivatives and distillates as well tar oils originating from coal gasification. These are often referred to as petroleum hydrocarbons (Cermak, 2010), also encompassing mono-and polycyclic aromatic structures of environmental and toxicological concern (Loibner et al, 2004).…”