Revision test Feb 27 2025: topic 4.4

What are the different types of aquatic pollutants?

• toxic metals

• synthetic compounds

• hot water

• oil spills

• radioactive pollution.

What are three direct methods to test the quality of aquatic systems?

Water temperature, pH, and presence of E. Coli.

What are two indirect methods to test the quality of aquatic systems?

Biological oxygen demand and biotic index of water.

What is biochemical oxygen demand (BOD) and how is it measured?

BOD is a measure of the amount of dissolved oxygen required to break down organic material in water, measured in a 5-day incubated sample at 20℃.

Define indicator species and give an example.

Indicator species are organisms that reflect specific environmental conditions; for example, lichen indicates air pollution.

What is the purpose of using biotic indices in pollution measurement?

Biotic indices measure pollution by assessing the impact on species based on their tolerance, diversity, and abundance.

Outline the process of biodegradation leading to methane, hydrogen sulfide, and ammonia.

Biodegradation utilizes oxygen, leading to anoxic conditions and anaerobic decomposition, producing methane, hydrogen sulfide, and ammonia.

Explain the process and impacts of eutrophication.

Eutrophication results from nutrient enrichment, causing algal blooms that block sunlight, leading to anoxic conditions and death of aquatic organisms.

What are the major causes of nutrient enrichment leading to eutrophication?

Causes include industrial nitrogen oxides, natural runoff of nitrates and phosphates, and agricultural runoff from fertilizers and manure.

How can pollution management strategies impact water pollution?

Pollution management strategies can help reduce the levels of pollutants entering aquatic systems and improve water quality.