ISSN:
1573-2932
Keywords:
base cations
;
bulk precipitation chemistry
;
catchments
;
protons
;
sulfate
;
throughfall chemistry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract Temporal trends in sulfate, base cation (Ca2+ + Mg2+ + K+), and H+ ion concentrations in bulk precipitation and throughfall samples collected over a seven year period (1989-95) in four forested catchments in Finland are presented. The catchments are in remote locations and span the boreal zone (61-69 °N). The stands represent old, undisturbed forests, and are composed of varying proportions of Scots pine, Norway spruce and deciduous species (mainly Betula spp.). Monthly SO4 2- and H+ ion concentrations in bulk precipitation averaged over the study period and catchments were: 18.7 µmol L-1 and 32.3 µmol L-1. The corresponding values for throughfall were: 37.4 µmol L-1 and 32.4 µmol L-1. Sulfate and H+ ion concentrations in bulk precipitation and throughfall both showed negative linear trends, which were significant (p 〈 0.05) for the three southernmost catchments. Concentrations and trend slope decreased northwards (e.g., bulk precipitation SO4 2- slope estimates: -1.6 to -1.0 µmol L-1 yr-1). The decline was greater for throughfall than for bulk precipitation, indicating a proportionally greater reduction in dry deposition than wet. The sum of base cation concentrations averaged 12.1 µmol(+) L-1 in bulk precipitation and 83.1 µmol(+) L-1 in throughfall. There were no significant trends in the sum of base cations (p 〉 0.05). It is concluded that the reported reduction in S emissions over the study period has resulted in a significant reduction in the acidity and SO4 2- concentration of bulk precipitation, and this reduction has has been reflected in throughfall concentrations. The greatest reduction has taken place in the southern part of the country.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005087627364
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