Water quality sampling: How do we test for pollutants in rivers?

Poor water quality is one the biggest threats to the health of the Great Barrier Reef but how do we know what pollutants are in our rivers?
This video shows the different ways that water quality samples are being taken in the Johnstone and Tully catchments as part of a local scale water quality monitoring program that is providing practical information to farmers to help them make decisions about land managment practices.