"Testing pollution levels in natural water bodies can require a considerable amount of gear and instrumentation. However, there is another much simpler solution. Observing the species of insects that live in natural water bodies and identifying them can reveal how polluted that particular water body is. This method of observing pollution in natural water bodies is called bio-monitoring and the particular insect species that help us in determining the approximate pollution levels are called bioindicators. Insects are an intrinsic part of aquatic environments, and there is an incredible diversity of insect species that can be found in natural water bodies around the world, although the types of species found can be regional and site-specific. Certain insect species can be found in even the most polluted habitats that can be found. For example, John Roach in National Geographic reports that the streams flowing into the Carson river in Nevada and northern California run below an abandoned sulphur mine located in the Sierra Nevada mountain range. Laced with toxic acids and heavy metals, although the US Environmental Protection Agency (EPA) had declared the sites as among the most polluted sites in the US in 2000, studies looking for the possibilities for the restoration of the
The essay urges you to develop skills in recognising organisms whose survival is intrinsically linked to the quality of water. Conversely you can gauge the quality of the surface water through a cursory inspection.