Question

What are the characteristics of a polluted lake?

• A. Low dissolved oxygen
• B. Clear
• C. High biochemical oxygen demand
• D. Turbid

Answer 1

Answer: (A), (C), (D)

The correct options are
A Low dissolved oxygen
C High biochemical oxygen demand
D Turbid

Freshwater lakes contaminated with pollutants, pesticide residues, agrochemicals, industrial effluents, organic substances, and municipal waste is the appropriate condition for explosive growth of algae. The algae proliferate rapidly utilizing the available nutrients, increasing the turbidity and alkalinity of the lake. They eventually die and the bacteria feed on them depleting all the dissolved oxygen and increasing the biochemical oxygen deman (BOD) of the lake.