The Hazard Index is calculated using which of the following formulas?

The Hazard Index (HI) is a crucial metric used in environmental health risk assessments to evaluate the potential for non-cancer effects from exposure to hazardous substances. The formula HI = (Chronic Daily Intake) / (RfD) accurately reflects this concept.

In this formula, Chronic Daily Intake represents the estimated quantity of a substance that can be expected to enter an organism's system over a given period, typically expressed in terms of dose (such as milligrams of substance per kilogram of body weight per day). The Reference Dose (RfD) is a value established based on scientific research that indicates the maximum allowable amount of a substance to which a person can be exposed daily over a lifetime without expecting any adverse health effects.

When the Chronic Daily Intake is divided by the RfD, the resulting Hazard Index provides a comparative measure of risk. A HI greater than 1 suggests that the intake exceeds the safe reference level, indicating a potential health risk, while a HI less than 1 implies that the exposure is below the guideline, and thus, is considered safe.

In contrast, the other options present different formulations that do not align with the standard method for calculating the Hazard Index. The calculation involving exposure duration or dose does not directly relate to how the HI