Before revision: Topsoil, as well as farm fertilizers and other potential pollutants, runoff unprotected farm fields when heavy rains occur.|400x400px A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.
After revision: Topsoil, as well as farm fertilizers and other potential pollutants, runoff unprotected farm fields when heavy rains occur.|400x400px A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely effects the usefulness of a resource.