Polynuclear Aromatic Hydrocarbons in the Soil System: Long-Term Changes, Behaviour and Current Levels in the U.K.

Evidence for a substantial increase in the PAH burden of U.K. soils over the last century is presented. Typical or normal levels of 14 PAH compounds in Welsh soils are defined. These vary over at least three orders of magnitude and generally reflect the atmospheric deposition flux of PAHs. Surface enrichment of PAHs in soils is marked, even in soils from remote locations. Soils with a naturally high organic matter content often have elevated PAH concentrations. In general soils contain a relatively uniform mixture of PAH compounds. This, and other observations, are discussed and interpreted as indicating that PAH inputs to and transport through soils are predominatory in the particulate form.