The specific ultraviolet absorbance (SUVA) is calculated using the absorbance of UV light at 254 nm ______ the concentration of _______

The specific ultraviolet absorbance (SUVA) is calculated using the absorbance of UV light at 254 nm ______ the concentration of _______

• A. multiplied by, TOC
• B. divided by, TOC
• C. multiplied by, dissolved organic carbon
• D. divided by, dissolved organic carbon

Answer: (D)

Specific Ultraviolet Absorbance measures how much UV light at 254 nm is absorbed per unit of dissolved organic carbon. By taking the UV254 absorbance and dividing it by the concentration of dissolved organic carbon, you normalize the optical signal to the amount of dissolved organic matter present. This reveals the intrinsic properties of the dissolved matter—especially its aromaticity—independent of how much DOM is in the water. Higher SUVA values indicate more aromatic, humic-like compounds, which can influence treatment challenges and disinfection byproduct formation. Using dissolved organic carbon (not TOC) ensures you’re focusing on the dissolved fraction that actually contributes to UV absorbance, since TOC includes particulates that don’t affect UV254 in the same way.

Specific Ultraviolet Absorbance measures how much UV light at 254 nm is absorbed per unit of dissolved organic carbon. By taking the UV254 absorbance and dividing it by the concentration of dissolved organic carbon, you normalize the optical signal to the amount of dissolved organic matter present. This reveals the intrinsic properties of the dissolved matter—especially its aromaticity—independent of how much DOM is in the water. Higher SUVA values indicate more aromatic, humic-like compounds, which can influence treatment challenges and disinfection byproduct formation. Using dissolved organic carbon (not TOC) ensures you’re focusing on the dissolved fraction that actually contributes to UV absorbance, since TOC includes particulates that don’t affect UV254 in the same way.