Which of the following are chemical parameters of water quality? A. pH B.…

Concept

Water-quality indicators are grouped by what they measure: physical parameters describe observable properties, while chemical parameters quantify chemical condition, dissolved constituents, or oxygen-related reactions.

Chemical indicators can express acidity, dissolved-mineral content, or oxygen condition and demand; physical indicators describe properties such as clarity, colour, or temperature.

Application

• pH expresses hydrogen-ion activity and therefore the acidic or alkaline chemical condition of water.

• Hardness arises mainly from dissolved calcium and magnesium salts, so it represents dissolved chemical constituents.

• Turbidity describes the loss of clarity caused by suspended particles and is treated as a physical parameter.

• Dissolved oxygen (DO) is the concentration of oxygen present in water and is a chemical water-quality parameter.

• Biochemical oxygen demand (BOD) is the oxygen required by microorganisms to decompose biodegradable matter and is a chemical water-quality parameter.

Cross-check and contrast

• Turbidity is based on light scattering and visual clarity, unlike measurements of chemical condition or oxygen status.

• DO measures oxygen currently present, whereas BOD measures oxygen demand during biological decomposition; both concern the chemical oxygen condition of water.

Result

Therefore, the chemical parameters in the list are pH, hardness, dissolved oxygen and biochemical oxygen demand; turbidity is excluded.