The Australian Health Investigation Level for dieldrin is 6 milligrams/kilogram for soil in a residential setting. In the US, the Regional Screening Level is 0.034 milligrams/kilogram. While most countries consider similar evidence to calculate investigation levels, the levels exist for different purposes.
It is not uncommon for regulatory authorities to base their assessments of chemical toxicity on different key studies or dose levels, and they can also apply different uncertainty factors.
The exposure and toxicity results are translated from animal studies to humans using complex models. The methods for deriving a HIL are based on similar scientific approaches and include large safety margins to protect human health.
The Australian Health Investigation Level for dieldrin is reviewed every ten years and was last reviewed in 2013.