Effect of Mineral Acidity on the Weathering of a Podzolic B-horizon from the Precambrian Shield, Ontario

56 Pages·1993·1.3 MB·English

by  Ontario Ministry of the Environment

3.33^i^
THE EFFECT OF MINERAL ACIDITY
ON THE WEATHERING OF A
PODZOLIC B-HORIZON FROM THE
PRECAMBRIAN SHIELD, ONTARIO,
CANADA
OCTOBER 1993
® Ministryof
Ontario Environment
andEnergy

ISBN0-7778-0833-1
THEEFFECTOFMINERALACIDITYONTHEWEATHERING
OFAPODZOLIC B-HORIZONFROMTHEPRECAMBRIANSHIELD
ONTARIO, CANADA
OCTOBER 1993
Cettepublicationtechnique
n'estdisponiblequ'enanglais.
Copyright: Queen'sPrinterforOntario, 1993
Thispublicationmaybereproduced fornon-commercialpurposes
withappropriateattribution.
PIBS2335

THEEFFECTOFMINERALACIDITYONTHEWEATHERINGOFA
PODZOLICB-HORIZONFROMTHEPRECAMBRIANSHIELD
ONTARIO, CANADA
Reportpreparedby:
BruceLaZerteandJoeFindeis
DorsetResearch Centre
MinistryofEnvironmentandEnergy

ABSTRACT
PodzolicBhorizonsfromasoilonthePrecambrianShield,Ontario,Canadawerecollected,
placed incolumns and treatedwith distilledwater, cation amendedwater, acidifiedwater
orcationand acidamendedwateroverafourmonthperiod. While the cationtreatment
had little effectrelative tothe control,the acidtreatmentremoved large quantities ofAl,
Si and base cations. The source of the leached Al was primarily Citrate-Dithionite-
Bicarbonate extractable Al, probably some form of gibbsite. However, even more
pronounced was a major within column migration of oxalate extractable Al-Si, perhaps
allophane orimogolite, downthe acidified columns. Theweatheringofprimaryminerals
contributed little to the leaching ofAl from the acidified columns. In contrast to many
other acidified podzols, organically bound aluminum is not the major soil fraction
contributingAl to acidicleachateinthis soil.
TABLEOFCONTENTS
Abstract i
Table ofContents ii
List ofTables iii
ListofFigures iv
Introduction 1
Sample Sitesand Collection 3
Laboratory Methods 4
Analytical Methods 6
Results 8
Leachate Chemistry 8
Bulk Soil Chemistry . . .. 11
ColumnAland SiBudgets 13
Discussion 17
Summary 21
Acknowledgements 21
References 22
LISTOFTABLES
Table 1 Bulk soil chemistry.
Table2 Total accumulate leachate mass from each soil column, averages and 90%
Confidence Intervals.
Table3 Bulksoilextractionsafterthetreatments,layeraverages(per140g)andtotals
(per 1400g).
LISTOFFIGURES
Figure 1 Concentrations over the duration ofthe experiment ofselected parameters
fromthe Control (DDWtreatment).
Figure 2 Concentrations over the duration ofthe experiment ofselected parameters
fromthe Cationtreatment.
Figure3 Concentrations over the duration ofthe experiment ofselected parameters
fromtheAcid treatment.
Figure4 Concentrations over the duration ofthe experiment ofselected parameters
fromthe Acid+Cationtreatment.
Figure5 pAl(-log[Al])versuspHforallleachatedata.TwogibbsitesolubiHtylinesare
shown: the upper line is for May et al.'s (1979) "natural" gibbsite, and the
lowerlineis forHemand Robertson's (1967) micro-cyrstallinegibbsite.