Water Chemistry & Contaminant Identification Flashcards

Which type of hardness cannot be removed by boiling water?

Answer: Permanent hardness

Permanent (non-carbonate) hardness is caused by calcium and magnesium sulfates and chlorides, which are not removed by boiling.

Langelier Saturation Index (LSI) is used to predict water's tendency to:

Answer: Form or dissolve calcium carbonate scale

The LSI predicts whether water will precipitate (positive LSI) or dissolve (negative LSI) calcium carbonate scale.

Arsenic contamination in groundwater is most commonly associated with:

Answer: Natural geological formations

Arsenic occurs naturally in many geological formations and can leach into groundwater, especially in anaerobic conditions.

The presence of hydrogen sulfide gas in water is most commonly detected by:

Answer: Rotten egg odor

Hydrogen sulfide produces a distinctive rotten egg odor detectable at very low concentrations (below 0.5 ppb).

Which ion is responsible for 'blue staining' on plumbing fixtures?

Answer: Copper (Cu²⁺)

Copper ions in water cause characteristic blue-green staining on sinks, tubs, and fixtures due to copper corrosion.

What does a nephelometer measure in a water sample?

Answer: Light scattering caused by suspended particles

A nephelometer measures turbidity by quantifying the scattering of light by suspended particles, reported in NTU.

Radium in drinking water is primarily regulated because it is:

Answer: A radioactive element linked to bone cancer risk

Radium is regulated in drinking water because it is radioactive and accumulates in bones, increasing bone cancer risk.