ConceptConceptDocsDocuments

IB ESS HL 4.4.3 Water Quality Measurement Question Bank

Interpret physical, chemical and biological indicators of water quality.

Syllabus
First assessment 2026
Course
ESS HL
Level
HL

Exam points

  • identify the aquatic-system process or pollution indicator
  • apply the relevant conservation, quality or management model
  • evaluate ecological and human trade-offs from evidence

4.4.3—Water quality measurement question 1

[Maximum number: 4]

Question (a)

(a)
Coliform bacteria one day after untreated sewage release

Figure:Coliform bacteria one day after untreated sewage release

Using Figure: Coliform bacteria one day after untreated sewage release, estimate the highest concentrations of coliform bacteria (in units/ 100 mL ) found in the St Lawrence River one day after the untreated sewage was released.

[ 1 ]

Question (b)

(b)
Coliform bacteria before untreated sewage release

Figure:Coliform bacteria before untreated sewage release

Figure:Untreated sewage release into the St Lawrence River

- Figure: Untreated sewage release into the St Lawrence River
- Figure: Untreated sewage release into the St Lawrence River: Montreal discharged 5-8 billion litres of untreated sewage into the St Lawrence River in November 2015; river pollution returned to normal within 4-10 days.
- Quebec discharged 110 million litres in November 2016; nationally, 205 billion litres of untreated sewage are released into Canadian rivers and oceans each year.

With reference to Figures: Untreated sewage release into the St Lawrence River, Coliform bacteria before untreated sewage release and Coliform bacteria one day after untreated sewage release, describe a method to monitor the impact of the release of untreated sewage into the St Lawrence River ecosystem.

[ 3 ]
All question bank results loaded