Earth and Environmental Science 11–12 · Year 11

Water quality of a local creek or pond: pH, conductivity, turbidity, dissolved oxygen and temperature (fieldwork)

Module 4: Human Impacts

PracticalMedium risk

School laboratory, not for home

In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

The idea

A handful of measurable properties show how land use upstream changes a waterway, and comparing them with published guideline values turns observation into evidence.

Safety card

Medium riskA teacher supervises

Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

Hazards

deep or fast water
unstable banks
contaminated water
snakes and sun

Controls

sample from the bank with a bucket
gloves and hand washing
no entry to the water
first-aid kit and phone
never enter a stormwater drain or channel: water can surge through it when it rains upstream

Note

Fieldwork: complete the school's excursion approval and a RiskAssess field risk assessment under NSW Department of Education procedures; any test reagents carried into the field fall under the Chemical Safety in Schools (CSIS) package, Section 1.

What you need

calibrated pH meter, conductivity meter (µS/cm), thermometer, turbidity tube, dissolved oxygen kit or probe
sample bottles, bucket on a rope, gloves, a safe bank position chosen in advance, field sheet
two sites at least 200 m apart: one upstream and one downstream of a drain, road or paddock
the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG) default guideline values for the relevant region

How to do it

At each site record time, weather, recent rain and a sketch of the banks and land use.
Take three water samples across the channel; measure temperature, pH, conductivity, turbidity and dissolved oxygen on each within 10 minutes of sampling.
Average the three and tabulate upstream against downstream.
Compare each value with the ANZG default guideline value for the region and flag any outside the range.
Draw a conclusion about the downstream input and propose the next measurement that would test it (for example nutrients).

What you should see

The result is the size of each upstream–downstream difference, reported with its spread over three samples. Sydney Water lists the dirt, oil and grease, animal droppings, litter and nutrient-bearing chemicals that stormwater carries, so a drain is a plausible source to test. A value is only called a concern when it falls outside the published ANZG default guideline value for the water type, and the report cites that value.

What changes

What you change: site (upstream or downstream of the input)
What you measure: pH, conductivity, turbidity, dissolved oxygen, temperature
What you keep the same: same day and time window
same instruments and calibration
same sampling depth
three samples per site

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Clear water has nothing wrong with it.
A single reading proves a pollution source.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Earth and Environmental Science Stage 6 Syllabus (2017), NESA; current, replaced by the 11–12 Syllabus (2025) from 2028EES11-11 EES11/12-1 EES11/12-2 EES11/12-3
Earth and Environmental Science 11–12 Syllabus (2025), NESA; to be implemented from 2028, not yet taughtEES-11-03
Investigating Science Stage 6 Syllabus (2017), NESA; currentINS11-9 INS11/12-3
Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.

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