2. The River Taff is formed when the Taff Fechan meets the Taff Fawr. The river then runs south and to Cardiff Bay. 'Photolibrary Wales photo library'

3. The Environment Agency samples the water at 3 locations in Cardiff 1. Tongwynlais, just north of Cardiff 2. Llandaff Weir, on the west of the city 3. BlackWeir, near the city centre Image produced from the Ordnance Survey Get-a-map service. Image reproduced with kind permission of Ordnance Survey and Ordnance Survey of Northern Ireland.

4. Ammonia Arsenic Benzene Boron Cadmium Calcium Chloride Chloroform Chlorophyll Chromium Copper Fluoride Iron Lead Mercury Methabenzthiazuron Magnesium Manganese Sodium Naphthalene Nickel Nitrate Nitrite Oxygen Orthophosphate Phosphate Vanadium Zinc They look at many different substances:

5. As well as taking some other measurements: flow pH suspended solids salinity hardness

6. To analyse the data (using the instruction sheet) and present your findings in a PowerPoint presentation