Pollutant

A pollutant or novel entity[1] is a substance or energy introduced into the environment that has undesired effect, or adversely affects the usefulness of a resource.

These can be both naturally forming (i.e. minerals or extracted compounds like oil) or anthropogenic in origin (i.e. manufactured materials or byproducts).

[1] When analyzed from a planetary boundaries perspective, human society has released novel entities that well exceed safe levels.

[3] Examples include persistent organic pollutants like PCBs, non-biodegradable plastics and heavy metals.

[3] Scientists have officially deemed that the planetary boundaries safe chemical pollutant levels (novel entities) have been surpassed.

[3] Fund pollutants are not destroyed, but rather converted into less harmful substances, or diluted/dispersed to non-harmful concentrations.

Measures of pollutant concentration are used to determine risk assessment in public health.

Industry is continually synthesizing new chemicals, the regulation of which requires evaluation of the potential danger for human health and the environment.

Risk assessment is nowadays considered essential for making these decisions on a scientifically sound basis.

Surface runoff , also called nonpoint source pollution , from a farm field in Iowa, the United States during a rainstorm. Topsoil, as well as farm fertilizers and other potential pollutants, runoff unprotected farm fields when heavy rains occur.
The night sky viewed from Luhasoo bog, Estonia with light pollution in the background