Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which compliance can be assessed. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact and drinking water.
Water quality varies widely from place to place. Seasonal variations in water quality are also common. Water quality can be measured by analyzing water samples or assessing indicators at specific sites.
The physical characteristics of water are determined by factors such as temperature, pressure, dissolved minerals and gases, suspended particles, and pH. These characteristics influence the chemical properties of water, which in turn support the organisms that live in it and determine its suitability for different uses. The health of aquatic ecosystems is determined by their ability to maintain a balanced state in the face of changes in these physical and chemical conditions.
The safety of human contact with water depends on its microbial content, which is influenced by environmental conditions such as temperature, pH, dissolved oxygen levels, and the presence of nutrients and organic matter. Drinking water quality is determined by concentrations of certain chemicals that may be harmful to human health if consumed in high enough quantities. These include metals (such as lead and mercury), disinfection byproducts (such as trihalomethanes), pesticides (such as atrazine), volatile organic compounds (such as benzene) ,and radionuclides (such as uranium).
In order to protect public health and aquatic ecosystems, it is important to monitor trends in water quality over time and identify potential sources of pollution.;This can be done through routine monitoring programs that collect data on specific parameters at fixed locations on a regular basis.,/It can also be done through targeted studies that focus on specific issues or areas.,/ Trends can then be analyzed to identify problems early so that they can be addressed before they become serious threats.,/Monitoring programs require both financial resources