The Werribee River is a perennial river running from Daylesford to Werribee South, where it enters Port Phillip. It supports a variety of animal and plant life, including the endangered Growling Grass Frog, and is used for irrigation in the food producing region of Bacchus Marsh. Therefore, water quality tests are conducted regularly by water agencies to ensure the ongoing health of the waterway. A variety of parameters may be measured to provide an overall water quality rating including pH, salinity, temperature, dissolved oxygen, nitrogen (as nitrates), phosphorus (as phosphates), turbidity and metal concentrations.

Metals play an important role in water chemistry and water quality. Some metals are toxic at high concentrations whilst others play an essential role in water systems. Atomic absorption spectrometry (AAS), developed by Australian scientist Sir Alan Walsh, may be used to detect unknown concentrations of ~70 metals by comparing with calibration curves constructed using standard solutions. Analytical chemistry techniques used in the field and the laboratory compliment each other to provide comprehensive water quality datasets.

In this program, students will:

• Learn about the potential sources of contaminants in our waterways
• Understand how water quality is monitored in the field and laboratory
• Develop their understanding of spectroscopy
• Differentiate between qualitative and quantitative data
• Apply their stoichiometry and graphing skills to make up standards and plot a calibration curve
• Develop their wet laboratory skills and identify common sources of experimental error
• Gain an understanding of potential careers pathways and how chemical knowledge is applied in practice

Students will:

• Use field-based techniques (pH and conductivity meters, colorimetry, titration kits) to analyse water samples from the Werribee River
• Conduct flame tests with metallic solutions
• Perform calculations and prepare sodium standards
• Construct a calibration curve using data obtained from their standards
• Analyse the salinity of water samples from the Werribee River using atomic absorption spectroscopy
• Interpret and comment on their results by comparing them with published water quality standards

Ecolinc Learn Online is a virtual outreach learning management system (LMS) offering interactive online courses for students and teachers. These courses can be undertaken either as a pre-visit, post-visit or stand-alone.

Students are encouraged to do the pre-learning course on Ecolinc Learn Online called Safe Labs prior to coming to Ecolinc. In this course students will cover all the necessary aspects of laboratory safety during their time at Ecolinc. When planning any work in a laboratory the risk of exposure to laboratory hazards is an important consideration. This course is part of Ecolinc’s risk minimisation for student safety.

Area of Study 2: How are chemicals measured and analysed?

Analysis for salts

• Sources of salts found in water or soil (which may include minerals, heavy metals, organo-metallic substances) and the use of electrical conductivity to assess the salinity and quality of water or soil samples.
• Use of a calibration curve to determine the concentration of ions or complexes in a water or soil sample.

Analysis for acids and bases

• Application of volumetric analysis, including use of indicators, calculations related to and the preparation of standard solutions, and dilution of solutions.