Surface water is all water that is still or flowing on the surface of the ground. These are waters that flow on the surface of the land surface. Worldwide the pollution of ocean, rivers, lakes, wetlands, reservoirs and creeks, is particularly serious due to the growing amount of wastewater that is often discharged without treatment.
The water quality variables can be grouped into the following broad categories:
- Basic variables (eg. water temperature, pH, conductivity, dissolved oxygen) used for a general characterization of water quality.
- Suspended particulate matter (eg. suspended solids, turbidity).
- Organic pollution indicators (eg. dissolved oxygen, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), ammonium).
- Indicators of eutrophication: nutrients (eg. nitrogen and phosphorus),
- Indicators of acidification (eg. alkalinity, sulphate, nitrate, aluminium).
- Major ions (eg. chloride, sulphate, sodium, potassium, calcium and magnesium) as essential factors in determining the suitability of water for most uses (eg. public water supply, livestock watering and crop irrigation)
- Metals (eg. cadmium, mercury, copper and zinc).
- Organic micropollutants such as pesticides and the numerous chemical substances used in industrial processes (eg. PCB, HCH, PAH).
- Microbiological indicator organism (eg. total coliforms, E.coli and faecal coliforms).
- Prevent water pollution and thus achieving good ecological status or potential of the waters.
- Surface water sampling in accordance with ISO 5667.
- Interpretation of analytical result.