Hi,

I think the safe limit is around 200 mg/kg for TPH.

For TPH limit from 250 mg/kg to 1050 mg/kg. For soil and undergroundwaters, they depend on protection zones, limit from 200 mg/kg soil in highly safed areas to 1250 mg/kg for the unsaturated zone and deep undergroundwater levels.

Good luck

Faramarz Abazari Thank you so much it is helpful for me.

Read this article.

Article Biodegradation and post-oxidation of fuel-weathered field soil

Thank you so much Dr. Rishikesh Bajagain .

It is helpful for me.