The Deposition of Trace Elements in the Environs of a Power Station

Trace elements in the atmosphere are mostly associated with particulates, although there may be some in the gaseous phase. There are diverse sources, natural and anthropogenic. Amongst natural sources are the weathering of rocks and soils, volcanism, erosion of metal-rich surface deposits, thermal spring activity, reactions at water surfaces, forest fires, biological methylation and plant growth (Swaine, 1984). Anthropogenic sources include mining operations, smelting and other industrial activities, combustion of wood, oil and coal, waste incineration, agricultural operations, tyre- and engine-wear and cremation (Swaine et al., 1989). Enhanced inputs may occur near sources, but these are diluted by wind action which disperses trace elements long distances, thereby adding to background concentrations.