English to Russian Tech/Engineering Environment & Ecology терминология

Уважаемые, перевожу некий документ по очистке сточных вод. В разделе определений читаю:
Contaminant - The U.S. EPA definition: “Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil."
A more realistic definition is any substance, not naturally occurring, that has the potential to adversely affect the use of the receiving water body.
Pollutant - The U.S. EPA definition: “Any element, substance, compound, or mixture, including disease causing agents, which after release into the environment and upon exposure, ingestion, inhalation, or assimilation into any organism, either directly from the environment or indirectly by ingesting through food chains, will or may reasonably be anticipated to cause death, disease, behavioral abnormalities, cancer, genetic mutation, physiological malfunctions, or physical deformation in such organism or their offspring."
A more realistic definition is any substance added to a water body that has an adverse impact on human health or the environment.
Вопрос - как бы грамотно развести эти термины на русском языке?
Спасибо