Water pollution testing is a broad term which includes chemical, biological and physical testing of certain body of water.
Chemical testing usually refers to examination of pH levels in water, biochemical and chemical oxygen demand as well as the level of nutrients and metal in the water.
Biological testing on the other hand examines the level of water pollution by monitoring the condition of plants and animals in certain aquatic ecosystem
Physical testing includes measuring the temperature of water, turbidity and the concentration of total suspended solids.
The time factor is of extreme importance in water pollution testing. This is because many pollution events can be identified only in certain time, in most cases when there is a rain. This is the main reason why in many cases just grabbing the sample of water isn't enough to fully measure the level of pollutants in water.
The water is usually first being tested on-site with researchers measuring the temperature, pH levels, dissolved oxygen and oxygen reduction potential and turbidity. More comprehensive testing is done in the laboratory. However, the question about the accuracy of laboratory testing always remains open because it is very difficult to determine the extent to which the taken sample may be representative of the water quality (samples may for instance vary seasonally).
Once a sample is taken it is also important to make sure that sample container is made of materials with minimal reactivity with substances to be measured, not to mention how important it is to always clean sample container prior to taking sample. Researchers also tend to keep the samples cold in order to minimize the chance of possible chemical reactions with surrounding environment.
If you live near a potential source of water pollution such as factories, landfills and large agricultural areas it is wise to test the quality of water from time to time. Polluted water can spread many different waterborne diseases such as diarrhea.
The most obvious signs of water contaminated with pollutants include odd taste or smell, colored water which appears filthy, less effective cleaning ability of soaps and detergents, plumbing containing lead pip or solder joints, etc.
In United States water quality is monitored by the U.S. Environmental Protection Agency (EPA). This body regulates the concentrations and types of chemicals that may be found in drinking water. In United States all laboratories that conduct water testing must first obtain certificate by EPA.