If yes, what is the permitted range for vegetable oils. I tried searching for but could not get. Or can one use the permitted range for soil, water and air for comparison.
Article Comparative Evaluation of Some Metals in Palm Oil, Groundnut...
I do not think there is any regulatory standard for heavy metals (HMs) in vegetable oils. I would suggest that you compare your results with the WHO/FAO standard for edible foods or you adopt the ATSDR regulation.