30798
title and abstract
Toxicity and toxicokinetics of binary combinations of petroleum hydrocarbon distillates with the earthworm Eisenia andrei.
Petroleum hydrocarbons (PHCs) act via narcosis and are expected to have additive toxicity. However, previous work has demonstrated less-than-additive toxicity with PHC distillates and earthworms. A study was initiated to investigate this through toxicity and toxicokinetic studies with the earthworm Eisenia andrei. Three petroleum distillate fractions, F2 (>C10-C16), F3a (>C16-C23), and F3b (>C23-C34), were used in two binary combinations, F2F3a and F3aF3b. In the toxicity study, clean soil was spiked with equitoxic combinations of the two distillates ranging from 0.5 to 2.5 toxic units. In the toxicokinetic study, a binary combination consisting of one concentration of each distillate was used. On a soil concentration basis, the toxicity of the binary combinations of distillates was less than additive. Accumulation of the individual distillates, however, was generally reduced when a second distillate was present, resulting in lower body burden. This is thought to be due to the presence of a nonaqueous-phase liquid at the soil concentrations used. On a tissue concentration basis, toxicity was closer to additive. The results demonstrate that tissue concentrations are the preferred metric for toxicity for earthworms. They also demonstrate that the Canada-wide soil standards based on individual distillates are likely protective. Environ. Toxicol. Chem. 2013;32:1016-1026. © 2013 SETAC.