title: Seasonal change in the level and the chemical forms of aluminum in soil solution under a Japanese cedar forest.
abstract: The level of dissolved aluminum and its chemical forms in soil solutions consecutively collected by a porous cup vacuum sampler were monitored over a period from January 2001 to December 2001 at a Japanese cedar (Cryptomeria japonica) forestry area susceptible to acid deposition to characterize current soil dynamics and to evaluate potential tree damages. Distinction and characterization of Al species with differential toxicities were performed by two complementary speciation techniques; cation-exchange HPLC with fluorometric detection using 8-hydroxyquinoline-5-sulfonic acid (HQS) and size-fractionation/inductively coupled plasma atomic emission spectrometry (ICP-AES). The concentrations of free Al (mainly Al3+ and Al(OH)2+) and inert Al (existing as the complexed and/or colloidal forms) ranged between 0-150 microM and 10-50 microM, respectively. The concentrations of inert Al were mostly below 40 microM during an annual cycle and showed no marked seasonal variation, while free Al concentrations showed a clear tendency to increase in the spring and summer seasons (in the period from April to August) probably due to the enhanced activity of microbial nitrification and the resultant soil acidification. Major cations and anions were also regularly determined and their seasonal changes were correlated with that of the dissolved Al concentration. Correlations between total Al (mainly existing as free Al) and the related species (and environmental conditions) were as follows: Al and Mg (R=0.96, P<0.01), Al and Ca (R=0.97, P<0.01), Al and NO3- (R=0.68, P<0.01), Al and temperature (R=0.68, P<0.01), Al and solution pH (R=-0.61, P<0.01), solution pH and NO3- (R=-0.65, P<0.01).
authors: Department of Chemistry, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors: Tomonari
authors: T
authors: Umemura
authors: Yosuke
authors: Y
authors: Usami
authors: Sho-ichi
authors: S
authors: Aizawa
authors: Kin-ichi
authors: K
authors: Tsunoda
authors: Ken-ichi
authors: K
authors: Satake
mesh_terms: D015258:Acid Rain; D000535:Aluminum / Q000032:analysis* / Q000737:chemistry*; D032485:Cryptomeria; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D007564:Japan; D009584:Nitrogen / Q000378:metabolism; D012621:Seasons; D012987:Soil; D014197:Trees
chemical_list: D015258:Acid Rain; D012987:Soil; D000535:Aluminum; D009584:Nitrogen