Ab. Mackenzie et al., A historical record of atmospheric depositional fluxes of contaminants in west-central Scotland derived from an ombrotrophic peat core, SCI TOTAL E, 222(3), 1998, pp. 157-166
An ombrotrophic peat core from west-central Scotland was subjected to multi
-element analysis and (210)pb dating in order to estimate historical trends
in atmospheric deposition of contaminants. The inferred depositional flux
of ash (total inorganic material) exhibited small, transient increases from
as early as the mid 18th century, followed by a larger increase from the m
id 19th century to a pronounced maximum approx. 1960. A significant decreas
e was observed from the peak ash deposition of 29.2 g m(-2) year(-1) to the
contemporary level of 11 g m(-2) year(-1), although this is still an order
of magnitude greater than the pre-industrial value of 11 g m(-2) year(-1).
Depositional fluxes of a wide range of elements (scandium, copper, arsenic
, antimony, samarium, cobalt, bromine, lanthanum and lead) also exhibited m
ajor increases from the mid 19th century and peak values in the mid 20th ce
ntury (approx. 1940-1950). Aluminium, cerium and bromine also showed eviden
ce of transiently increased deposition as early as the mid 18th century. No
rmalisation of the concentrations of individual elements to that of alumini
um confirmed that the peak depositional fluxes in the mid 20th century were
not due to increased re-deposition of soil minerals from the atmosphere, b
ut were attributable to other sources of contamination including heavy indu
stry, coal burning and vehicle exhaust emission. Nevertheless, re-deposited
soil minerals were estimated to constitute an important fraction of the as
h, with peak input at the start of the 20th century and subsequent depositi
on at a relatively constant level, about half that of the maximum flux. Exc
ellent agreement was observed between the inferred trends in contaminant de
position and the known history of industrial development of the area. (C) 1
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