Which measurements are commonly used to assess organic pollution load and suspended solids in water quality assessments?

• A. pH, Temperature, and Salinity
• B. Chloride, Sulfate, and Nitrate
• C. Alkalinity, Hardness, and Color
• D. BOD, COD, and Turbidity

Answer: (D)

The main concept here is that organic pollution load and suspended solids are best assessed with indicators that quantify organic matter and particle content in the water.

Biochemical Oxygen Demand (BOD) measures how much dissolved oxygen microorganisms will use to break down biodegradable organic matter. A higher BOD indicates a greater organic pollution load and a higher potential to deplete oxygen in the water, which can harm aquatic life.

Chemical Oxygen Demand (COD) provides a faster, broader estimate of the amount of oxygen required to oxidize both biodegradable and non-biodegradable organic matter. Together with BOD, COD gives a fuller picture of the total organic pollution present.

Turbidity gauges how cloudy the water is, reflecting the amount of suspended solids. Elevated turbidity signals more particles in the water, which can include organic debris and inorganic matter, affecting water quality and treatment processes.

The other options focus on properties like pH, temperature, salinity, inorganic ions, or mineral content, which don’t directly measure the organic pollution load or suspended solids.