Chromosome aberrations and loss of some cell functions following in vitro exposure to retorted oil shale. [Cultured cells were exposed to processes oil shale particles (spent shales)]

An investigation of cellular level effects of processed oil shale from a simulation of modified in situ retorting was undertaken as part of an assessment of the toxicity and mutagenicity of oil shale. Complete assessment of the health hazards associated with physical contact, inhalation, or ingestion of oil shale has not been examined in humans and until it becomes practical to assess these hazards in man, we must rely upon well established in vitro detection procedures in addition to whole animal testing. CHO cells and L-2 rat lung epithelial cell lines were exposed in vitro to processed oil shale particles at different intervals following exposure. Cells were analyzed for chromosome alterations, cell colony forming ability, DNA synthesis, and cell transformation. The results of these studies demonstrate that retorted oil shale, under these experimental conditions, does modify cells in vitro. Chromosome aberrations increased with dose, cell colony forming ability decreased exponentially with dose, and the rate of DNA synthesis was affected, however cell transformation was not demonstrated after 3 months.