A3.2.8 Toxic Organic Micro-Pollutants TOMPs


Toxic Organic Micro-Pollutants (TOMPs – again, an abbreviation and not a chemical formula) are a complex range of chemicals produced by the incomplete combustion of fuels.

Compounds in this category include:

  • PolyAromatic Hydrocarbons (PAHs)
  • PolyChlorinated Biphenyls (PCBs)
  • Dioxins


TOMPS can cause a wide range of effects, including cancer, reduced immunity, nervous system disorders and child development.

PolyAromatic Hydrocarbons (PAHs)

PAHs is a generic term for a chemical compound that contains more than one fused benzene ring. They are commonly found in petroleum fuels, coal products, and tar.

PAHs can accumulate in living tissue. They are carcinogenic and are able to interfere with hormone systems and reproduction.

PCBs (PolyChlorinated Biphenyls)

There are no known natural sources of PCBs. They were widely used for many applications, especially as dielectric fluids in transformers, capacitors and coolants.

PCBs have been detected globally in the atmosphere, from the most urbanized areas that are the centers for PCB pollution, to regions north of the Arctic Circle. The atmosphere serves as the primary route for global transport of PCBs.

PCBs do not readily break down in the environment and therefore may remain there for very long periods of time. They are extremely toxic and are classified as a Persistent Organic Pollutant (POP).


Dioxin are a family of complex chemicals. There are several hundred dioxin substances. Some dioxin-type compounds are toxic at very low levels.

They tend to be released through the burning of agricultural wastes, chemical manufacture, power stations and vehicles. Dioxins are eventually deposited onto soil and vegetation. Those deposited onto grass may be eaten by livestock and enter the food chain, as may those deposited into aquatic sediments (via fish).