1 Water is precious
Water is our most precious resource. Without water, life on Earth, including humans, would not exist. The need to value water is becoming more critical in the face of global issues such as a changing climate and increasing human population. This is not only the case in arid and less economically developed parts of the world, but also in wetter, more developed countries such as the UK.
Monitoring water quality is a key aspect in managing our water so that we and future generations have what we need and so that the environment is protected. Human activities, natural landscape features and atmospheric contributions can all have an effect on water quality (Figure 1).
Figure 1 Chemical contamination of water resources © The Open University
Show description|Hide descriptionThe diagram shows how various human activities cause chemical contamination of water resources. It depicts a three-dimensional cross-section of land. Chemical contamination is shown to occur via run-off from a number of different sources, including landfills, waste water, leaking sewers, septic tanks, contaminated land, manure spreading, and pesticides and fertilizer application. The diagram shows how contaminants seep into the ground and then into the groundwater flow. Annotation: The following notes are positioned next to the sources of contamination: "Point-source contamination can be traced to specific points of discharge from wastewater treatment plants and factories or from combined sewers.”; “Air pollution spreads across the landscape and is often overlooked as a major nonpoint source of pollution. Airborne nutrients and pesticides can be transported far from there area of origin.”; “Eroded soil and sediment can transport considerable amounts of some nutrients, such as organic nitrogen and phosphorous, and some pesticides to rivers and streams.
In broad terms, water quality can be seen as the chemical, physical and biological characteristics of water, and is measured against requirements for human or other species/ecosystem uses. Such requirements often take the form of standards (such as for drinking water or ecosystem health) against which samples can be assessed to check compliance with regulations.
