What kind of risk are you trying to do the assessment? An environmental risk assessment or human exposure risk assessment?

Definitions:

- Acceptable Daily Intake (ADI): Estimate of the amount of a substance in food or drinking water, expressed on a body-mass basis (usually mg/kg body weight), which can be ingested daily over a lifetime by humans without appreciable health risk. For calculation of the daily intake per person, a standard body mass of 60 kg is used. ADI is normally used for food additives (tolerable daily intake is used for contaminants).

 - Risk Quotient (RQ): Is calculated from an estimated exposure (PEC), divided by an estimated effect (PNEC). If a value less than 1, then there is an acceptable risk. In contrast, if the RQ greater than 1, there is an unacceptable level of risk and measures to reduce exposure should be taken.