Toxicological Assessment of Heavy Oil and Sulfur-containing Oil Components by Various Conventional Biological Tests

Studies on Heavy Oil Components in Food. II

Abstract

In order to make a toxicological assessment of organic sulfur compounds in heavy oil various conventional biological tests were applied.
(1) Killifish test for median tolerance limit (TLm 24hr). (2) Drosophyla growth test. (3) Chicken embryo assay. (4) Mutagenic activity to Salmonella typhimurium TA 98. (5) Sea urchin egg growth test.
The results were as follows: TLm 24hr of C class heavy oil corresponded to around 80ppm, while A and B class heavy oil gave over 100ppm. TLm 24hr of dibenzothiophene was 17ppm. No significant effects of heavy oils on the developmental stage of Drosophyla were observed.
In the sea urchin egg growth test, the effective concentration of dibenzothiophene was 25ppm, i. e., this compound was more toxic to marine or fresh water organisms than heavy oil itself.
Higher boiling distillate oil such as B and C class heavy oil showed higher toxicity to chicken embryos than A class heavy oil.
In the tests for mutagenic activity using TA 98, B class heavy oil showed slight mutagenicity at a concentration of 500μg/plate. Sulfur compounds (benzothiophene and dibenzothiophene) and sulfur containing oil fraction from heavy oil appeared to exhibit no mutagenicity with respect to TA 98.