Hazard Index Calculator

Formula

To calculate the Hazard Index:

\[ HI = \sum \left( \frac{ED_i}{RfD_i} \right) \]

Where:

\(HI\) is the Hazard Index
\(ED_i\) is the Exposure Dose for contaminant \(i\) (mg/kg/day)
\(RfD_i\) is the Reference Dose for contaminant \(i\) (mg/kg/day)

What is a Hazard Index?

A Hazard Index (HI) is a tool used in environmental health risk assessment to measure the potential risk of non-carcinogenic health effects from exposure to multiple hazardous substances. It is calculated by adding up the hazard quotients of each substance, which are the ratios of the potential exposure to the substance over a specified period to the reference dose. An HI of less than 1 indicates that no adverse health effects are expected, while an HI greater than 1 suggests potential health risks.

Example Calculation 1

Let's assume the following values:

Exposure Dose (\(ED_1\)) = 0.05 mg/kg/day
Reference Dose (\(RfD_1\)) = 0.1 mg/kg/day
Exposure Dose (\(ED_2\)) = 0.02 mg/kg/day
Reference Dose (\(RfD_2\)) = 0.05 mg/kg/day

Using the formula:

\[ HI = \left( \frac{0.05}{0.1} \right) + \left( \frac{0.02}{0.05} \right) = 0.5 + 0.4 = 0.9 \]

The Hazard Index is 0.9.

Example Calculation 2

Let's assume the following values:

Exposure Dose (\(ED_1\)) = 0.1 mg/kg/day
Reference Dose (\(RfD_1\)) = 0.2 mg/kg/day
Exposure Dose (\(ED_2\)) = 0.05 mg/kg/day
Reference Dose (\(RfD_2\)) = 0.1 mg/kg/day

Using the formula:

\[ HI = \left( \frac{0.1}{0.2} \right) + \left( \frac{0.05}{0.1} \right) = 0.5 + 0.5 = 1.0 \]

The Hazard Index is 1.0.