Summary of Overburden Studies at Olkiluoto with an Emphasis on Geosphere-Biosphere Interface. Working Report

Transcription

1 orking eport 200- ummry of verburden tudies t lkiluoto with n mphsis on eosphere-iosphere nterfce nne-j hdenperä Jorm lmén irjo ellä rch , el -2-2 x

2 orking eport 200- ummry of verburden tudies t lkiluoto with n mphsis on eosphere-iosphere nterfce nne-j hdenperä Jorm lmén irjo ellä J-intct y rch 200 se mps tionl nd urvey, permission 0 orking eports contin informtion on work in progress or pending completion he conclusions nd viewpoints presented in the report re those of uthor(s nd do not necessrily coincide with those of osiv

3 hdenperä, -, lmén, J ellä, 200 ummry of verburden tudies t lkiluoto with n emphsis on eosphere-iosphere nterfce osiv y, orking eport he im of this work is to synthesize the existing geotechnicl, geochemicl, minerlogicl nd hydrulic dt from the overburden t the lkiluoto site he dt hs been collected in different studies s prt of the chrcteristion progrm for the disposl of spent nucler fuel minly during 200 oil nd pet smples from open test pits t vrious depths hve been tken nd nlysed he extent of the nlyses progrmme hs vried between the smpling uternry deposits in the study re were studied in soils test pits dug by excvtor nd four pet test cores tndrd procedures were pplied in logging physicl properties wo extrctions were used to emulte different environmentl conditions in soils ollowing determintions nd chemicl nlyses were crried out p, wter content, orgnic mtter, nions (l,, nd nd metls (l,, s, e,, g,, nd r n ddition, ummry tbles most of the vilble physicochemicl dt from soil nd pet smples were prepred he hydrulic conductivity in overburden hs been mesured in the groundwter observtion tubes (-holes he mesurements were conducted by using the soclled slug-test technique he fluctution of wter tble, dry top lyer vs ground surfce elevtion nd dry top lyer thickness vs overburden thickness in shllow boreholes nd uppermost levels of multi level piezometers (-holes re lso presented eywords verburden, soil nd pet smples, strtigrphy, geochemistry, hydrulic properties

4 Ä ÄÄ- ÄÄ J Ä utkimuksess yhdistettiin geotekninen, geokemillinen, minerloginen j hydrulinen ineisto lkiluodon lueelt ineisto koostuu pääosin eri tutkimuksist vuosilt 200, jotk on tehty käytetyn ydinpolttoineen loppusijoitustutkimust vrten perä- j turvenäytteet on otettu j nlysoitu eri syvyyksiltä äytteenoton j nlyysien ljuus vihteli eri näytteenottokerroill peränäytteitä otettiin trktorikivurill kivetust koekuopst j turvenäytteitä neljästä pisteestä tilvuustrkll mäntäkirll peränäytteiden fysiklisten ominisuuksien määrittämisessä käytettiin vllitsevi stndrdimenetelmiä ht eri uutto käytettiin kuvmn erilisi geokemillisi olosuhteit mperässä äytteistä määritettiin p, vesipitoisuus, orgninen ines, nionit (l,, j j metllit (l,, s, e,, g,, j r isäksi rportin loppuun on koottu tulukot mperä- j turve - rporteiss minituist merkittävimmistä fysiklis-kemillisist nlyysituloksist perän vedenjohtvuus on mitttu pohjvesiputkist (-reiät ittukset suoritettiin käyttäen niin kutsuttu slug-testiä portiss esitetään vedenpinnn vihtelu, kuivn mkerroksen suhde pintmn korkeuteen j kuivnmn pksuuden suhde mperän pksuuteen mtliss kirnrei issä j eritsopietsometrien ylimmissä tulppväleissä vinsnt rtom, mperä- j turvenäytteet, strtigrfi, geokemi, hydruliset ominisuudet

5 Ä 2 2 verburden nd soil types 22 verburden physicl nd chemicl properties 22 oil smples 222 et smples 2 ydrulic properties verburden nd soil types oil smples 2 et smples 2 2 ydrulic properties 2 ppendix lement concentrtions in different depths in test pit ppendix 2 lement concentrtions in different depths in test pit 0 ppendix lement concentrtions in different depths in test pit ppendix lement concentrtions in different depths in test pit 2 ppendix lement concentrtions in different depths in test pit 0 ppendix lement concentrtions in different depths in test pit ppendix lement concentrtions in different depths in test pit 2 ppendix lement concentrtions in different depths in test pit kk ppendix hysicl nd chemicl chrcteristics of soil test pits kk-kk, rk-rk ppendix 0 hysicl nd chemicl chrcteristics of pet test pits wp00-wp00

6 2

7 osiv y is crrying out progrmme for the development of geologicl repository t lkiluoto for spent nucler fuel he construction of the underground reserch fcility strted in summer 200 he construction of will enble detil studies of the bedrock t the intended repository depth, but will lso cuse disturbnces in the nturl conditions t the site osiv y hs published report describing the bseline conditions tht exist prior to excvtion of the (osiv 200 nd currently n updte of this description is being prepred tking into ccount lso the ltest investigtions results vilble prior the commence of excvtions his report presents summry of the vilble informtion from the overburden with n emphsis on geosphere-biosphere interfce nd the informtion needed in the modelling of the geosphere-biosphere interfce for the long term sfety ssessment ( n trditionl modelling, the geosphere-biosphere interfce zone (Z hs been considered to be technicl issue of converting the modelling results of rdionuclide trnsport in the bedrock (qm of groundwter t the upper boundry of the fr field to the source term of the biosphere model (qy into specific comprtment n the relity, however, the properties nd processes in the overburden might ffect the groundwter flow drsticlly nd the dose to the humn nd to the biot hus the overburden conditions nd the source term for the biosphere models need to be better defined on the bsis of the knowledge on the site igure depicts the role of overburden s geoshpere-biosphere interfce nd shows the difference to the trditionl conceptulistion he report concentrtes on the distribution of the soil types t the lkiluoto slnd, mechnicl nd chemicl properties of the overburden s well s in hydrulic conductivity of the overburden he shoreline of lkiluoto is continuously chnging due to two interctive verticl movements, glcio-isosttic depressionuplift nd globl eusttic se level loweringrise (eg osiv 200 lso sedimenttion of solid mterils brought to the re by the rivers urjoki nd pinjoki seemingly hppens in the strits north nd south of lkiluoto nd eutrophiction nd pludifiction of shllow bys ffect the shoreline nd lso evolution of the overburden hese phenomen re not discussed in this report (see eg osiv 200, neither re the chemistry of the of the groundwter smples from the overburden, which itkänen et l (200 nd röger et l (200 describe ysimeters nd mesurement weirs hs been instlled t the site for monitoring purposes, but s there re only preliminry results vilble, these were not discussed in this context

8 igure he difference between the concepts of trditionl sfety ssessment pproch nd the relity (igure by ri konen, osiv y

9 2 nformtion on the overburden t the lkiluoto slnd is bsed on test pits, geophysicl surveys nd some core smples n ddition, some informtion is gined from borehole drilling nd instlltion of groundwter tubes he most detiled dt on overburden is vilble for the centrl prts of islnd, where the investigtions hve been focused on igure 2 shows the loction of the investigtion points providing min informtion of the overburden properties igure 2 p of investigtion points providing min informtion of overburden properties soil types re defined in test pits (, in red nd pet types from the smpling points t the lkiluodonjärvi wetlnd re ( in green, hydrulic conductivity mesurements nd groundwter smpling hs been done in groundwter observtion tubes ( in blue he bckground shows the thickness of overburden

10 2 verburden nd soil types n the bsis of silviculturl inventory in 200, the most common soil types in the study re re on verge fine-textured ( nd sndy ( till he other types re grvelly till ( nd pet ( in ddition to one percent of outcrops (utio et l 200 hese estimtes will be revised in within the extensive forest plot inventory nd smpling (osiv 200 round-penetrting rdr probing ws crried out on the lkiluodonjärvi wetlnd re in 200 he im ws to mp thickness of pet lyers nd overburden nd to produce informtion on the degree of frcturing of the bedrock s surfce prt if possible owever, the till ws so conductive tht ground penetrting probing ws not ble to rech the bedrock surfce (eino 200 ecently, eologicl urvey of inlnd hs mpped the soil types long two investigtion trenches nd (uht 200 he test pits - dug by excvtor (gros, intinen et 200 nd intinen helin 200 nd pet test cores in lkiluodonjärvi re (konen 2002 nd their physicl nd chemicl nlysis of the smples re described more detiled in this report he results of refrction seismic mesurements cn be used to interprete overburden thickness zones in bedrock surfce ehtimäki (200 provides n integrted interprettion of the vilble refrction seismic dt covering the whole lkiluoto slnd more detiled study hs been performed on the centrl investigtion re (ehtimäki 200b hickness of the overburden is known t the investigtion points including the test pits nd groundwter tble monitoring points s well s other investigtion points eg boreholes nd seismic source points dditionlly, mp of the overburden thickness hs been prepred from the interpreted ground surfce nd bedrock surfce models (ittinen et l verburden physicl nd chemicl properties 22 oil smples etiled soil surveys were crried out t the lkiluoto site in utumn nd 2002, spring 200 nd 200 edimentry cover (uternry deposit in the study re ws studied nd smpled in test pits (- dug by excvtor n ddition (- shllow test pits were smpled for grin size nlyses in utumn 2002 he totl number of investigted smples ws ubjects of exmintion for the pits - were grin size, distribution of soils nd thickness of the soil cover (gros tndrd procedures were pplied in logging of physicl nd geotechnicl properties for the test pits of - including grin size, orgnic mtter, humidity, specific re, prticle density, permebility, compctness, stone content, stone size nd moisture he depth of test pits vried from m to m (gros, intinen et l 200, intinen nd helin 200 n ddition two test pit profiles (long investigtion trenches r0-0 nd r0-0 were used s reference dt he length of ws 0 meters consisting of 0 test pits dug by excvtor he depth of test pits vried from 0 m to m, being on verge 2 meters he length of ws 0 meters consisting test

11 pits he depth of test pits vried from to meters being on verge 22 meters (uht 200 ltogether soil smples hve been chemiclly nlysed wo extrction were used for smples of - to emulte different environmentl conditions highly redily soluble compounds were determined by extrcting 2 hours with synthetic rinwter, which consisted of mixture of deionised wter nd hving p, 2 the overll bundnce of significnt elements ws estblished by using microwve ssisted digestion, which hs widely been pplied to vrious environmentl mpping progrmmes he soil smples of the test pits 2 nd were only nlysed by using synthetic rinwter nions were nlysed using wter lech urthermore minerlogicl composition of 2 smples from the grin size frctions 2 mm nd 02 mm were determined by -method (intinen et l 200, intinen helin et smples lkiluodonjärvi is typicl young petlnd, which hs been initited on lnd uplift shores rimry mire formtion ws controlled the shore displcement of the ltic e only some hundreds yers go (ronen et l he pet nd mire lyers were found to be very thin (20-0 cm et ws minly wet nd wekly decomposed ommon eed-rex-pghnum pet n some plces thin rown pet lyers were found in the bottom of other pet lyers nder the pet nd mire lyers ws detritus nd cly mud, snd, cly nd till lyers mpling ws done in the spring 200 consisting four (00-00 test cores from pet lyers to upper prt of till lyers he totl depth of cores vried from 0 cm to m he geochemistry of the pet smples were investigted by tking seprtely from solid nd liquid phses through filter with help of disposble syringe nd nlysed in lbortories with stndrd methods he min elements were determined from smples s well s p, lklinity, ction exchnge cpcity nd totl orgnic crbon or determining the ctivity concentrtion of -2, s- nd s- few soil nd wter smples were mesured by gmm spectrometry (konen 2002 igure presents the strtigrphy for the deepest test core 00

12 igure trtigrphy for the deepest pet test core 00 situting in the middle of the lkiluodonjärvi wetlnd re 2 ydrulic properties onitoring of groundwter tble nd its fluctutions begn in ecember nd is normlly mde on weekly or monthly bsis using wter-level tpe probe ressure trnsducers linked to n utomtic dt cquisition system were used for specific periods nd for selected multi-level piezometers (-holes he observtion frequency for these piezometers vried between 0 minutes nd two hours he network for monitoring of the groundwter tble consists of hllow boreholes ( drilled for bedrock surfce smpling nd completed with steel csing, roundwter observtion tubes (,

13 eep boreholes (, shot-holes for (round the deep boreholes, holes for tube wve mesurements (round the deep boreholes, shot-holes for (close to the se line, ercussion drilled wells (, nd he uppermost levels of permnent multi-level piezometers ( onitoring of the wter-tble hs been lmost continuous in 2 shllow wells (-,, -0,, 2, nd nd in seven multi-level piezometers (- since the turn of 0 except for the brek between eptember 2 nd June hus, time-series mesurements hve been tken for over 0 yers from these wells ll long-term observtions re reported by hoks erv (2, änninen ( nd ehtimäki (200 test results (since spring 200 nd the summry of ll observtions re reported by oipio et l (200 reliminry results of the new mesurement performed fter 200 were lso included into this study xtension of the monitoring network took plce t the end of 200 when groundwter observtion tubes (t ten loctions, -0 were dded to the stndrd monitoring progrm n ddition, seven shllow wells in the centrl investigtion re were dded to the monitoring network in spring 2002 ws dded lredy in spring hus, regulr monitoring of the groundwter tble tkes plce, in shllow wells covering n re of bout km 2 (oipio et l 200ter, monitoring network of ground wter tble hs been extended nd covers currently boreholes nd over 0 shllow wells n ddition, groundwter-tble monitoring of wells round the J repository hs been performed since ovember 0 nd is presented in severl reports (hoks, Öhberg hoks, ykyri et l, b, Öhberg,, kl Öhberg, ievänen Öhberg, 2000, gros Öhberg 200, osiv y 200 ydrulic conductivity ( 2m in overburden ws mesured in the most of the observtion tubes (-holes by lowering the device with the pressure sensor during the summer 2002 (ellä eikkinen 200 reliminry results of the new mesurement results performed during 200 were lso included into this study he mesurements were conducted by using the so-clled slug-test technique n the slugtest the hydrulic hed in the borehole is bruptly chnged either by pouring wter in the borehole or by lowering the pressure sensor he recovery period is followed up nd the conductivity interpreted bsed on the chnge of the wter level in the mesurement hose he interprettion hs been done using the vorslev s method, but for the control lso hiem s eqution ws pplied (reeze herry he result presents the 2 m perforted section, which in -holes re just bove the bedrock surfce nd in the ner-by holes, the perforted section is in shllower prts of the overburden (minly the bottom of the perforted section is bout two meters bove the bedrock surfce (ehto 200 or comprison, the hydrulic conductivity ws lso clculted using hiem s formul from the pre-pumping results mesured in connection of the groundwter smpling he mesurement results were interpreted using vorslev s method

14 0 igure roundwter tble (m bove se level with contour spcing of m (grey lines nd m (blck lines

15 verburden nd soil types he verge elevtion of lkiluoto is bout m bove se level he highest points of the investigtion site re iiklnkllio m, elkänummenhrju m nd lkopäänniemi 2 m ophogrphicl mp is presented in igure he bedrock surfce (igure cn vry loclly rther much, but the ground surfce (igure is still quite even t plces where the bedrock surfce bruptly chnges the depressions of rock surfce re filled with thicker lyer of till nd the outcrops stick through the modest soil lyers, s expected due to the pst ice sheets he overburden is minly fine-textured sndy till he other terrestril sediment types re, in order of bundnce, fine snd, snd, silt nd cly he thickness of the overburden is usully 2 - meters, lthough even up to 2- meter thick lyers hve been observed ome itorin nd ncylus cly res exist in ddition to the res of (sub- recent mud cover t the northern nd southern side of islnd (osiv 200 he seismic velocities showed quite mosic like ptterns, lthough some cler nomlous res were found ome of the interpreted broken bedrock points seem to be limited to surficl bedrock lyer, becuse the decresed seismic velocity does not continue deeper he seismic interprettions seem to gree with the observtions in the investigted trenches, where the bedrock surfce is firly unbroken (ehtimäki 200 efrction seismic surveys provide dt on the qulity of the bedrock surfce istribution of the seismic velocity t the whole lkiluoto islnd is shown in igure (ehtimäki 200 nd the more detiled mp of the centrl investigtion re with the interprettion frctured surfce in igure (ehtimäki 200b wo verticl cross-sections presenting the strtigrphy were prepred ee igure 0 for the loction of the cross sections t the ground surfce ine begins from vicinity of nd ends to the borehole ine 2 begins from nd ends to vicinity of he presenttions were designed by projecting to both lines the bedrock surfce, soil type (when reported nd ground surfce from ech one of the observtion points, which locted in less thn 0 m distnce from the ccording verticl profile line he projected dt ws interpreted to lyer model in ell ultiwellpresenttion he ground surfce, men groundwter tble surfce nd the bedrock surfce re drwn s section from the recent topogrphicl model of lkiluoto (ummel 200 s lines nd re superimposed on the verticl profile ell ultiwell imges

16 2 igure opogrphy t the lkiluoto slnd, with contour spcing of m (grey lines nd m (blck lines

17 igure edrock surfce (m, bove se level, red corresponds to m bove se level nd light blue res were bedrock surfce is below se level

18 igure hickness of the overburden ccording to ittinen et l (200 with the new investigtion points from yers providing informtion of the overburden thickness since the report by ittinen et l

19 igure eismic velocity in the bedrock surfce t the lkiluoto slnd he seismic velocity 000 ms corresponds sprsely frctured bedrock, ms corresponds low frctured bedrock, ms corresponds clerly frctured bedrock, ms corresponds densely frctured bedrock nd 00 ms corresponds cly structured bedrock (ehtimäki 200

20 igure eismic velocity t the centrl study re nterprettion of the broken bedrock surfce is shown (ehtimäki 200b

21 ine 20 ines nd 2 ine ine 2 2 ine igure 0 oction of the cross sections for the presenttion of the strtigrphy he presenttions were designed by projecting the bedrock surfce, soil type nd ground wter tble from the shown observtion points to the cross-section plnes

22 igure llustrtive overburden profile lines nd 2 t the centrl investigtion re (orizontl to verticl scle is 20 he nmed columns show the observtions the brown prt is till, long the profile grey is bedrock lue line shows the groundwter tble, grey line shows the bedrock surfce nd ornge line shows ground surfce (on the exct loctions of the profiles edrock surfce nd soil surfce elevtions t smpling points differ from the indictions of thin lines, s the smpling points re discriminted from the ctul profiles by smll distnce

23 oil smples hysicl properties n the investigted test pits till is sndy till, contining some cly, sndy, grvel nd wethered lyers he geochemicl composition of till depends on the wetherbility of rocks, the vrition in the direction of flow of continentl ice sheet nd type nd mount of re-deposited drift n some pits till is more stony or compct, especilly in deeper horizons n some isolted depressions lso fine grined glcilcustrine sediments were observed he till ws wekly lminted nd rich in fines bservtions of disintegrted rock lyers of rock debris between solid bedrock nd overburden were found in the test pits long the reserch trenches nd he depth of lyers vried from some ten cm to 2- meters n the profile the bundnce of disintegrted rock lyers ws clerly higher thn in the profile he lyers were slightly chemiclly chnged (so clled plrpkllio (uht 200 n cse tht chemicl wethering will proceed fr enough, the disintegrted rock lyers will enrich in cly minerls nd oxides of silicon, luminium nd iron (ulkkinen, äisänen rce metl concentrtions re substntilly higher in wethered lyers thn in till, where they increse s bundnce of wethering products in till increses (lminen levted concentrtions of soluble luminium hve been encountered in the illuvil horizon nd trnsition zone in res of disintegrted rock lyers (äisänen n the test pits cly ( 02 mm content usully vried from to n one shllow test pit (2 the cly content ws in the depth of 0 m he orgnic mtter content of till ws low, less thn 2 n the test pit glciotectonic folding nd boudinge structures were observed he boudinges contined drk finegrined till nd mic mteril, probbly representing mteril from older glciogenic deposits or wethered bedrock n the bsis of the test pit (- observtions, density of soil prticles ws 2-0 mgcm nd specific re 2-m 2 g he till in the study re cn be described s bsl till deposited by ctively flowing bsl conditions of the ice sheet (intinen et l 200, intinen nd helin 200

24 20 igure 2 trtigrphy of two verticl profiles, brown columns re till, green column indictes snd nd grvel, spotted columns re humus, blck is bedrock nd no observtions lck horizontl lines mrk the depth intervls where the grin size distribution ws nlysed

25 2 inerlogy he minerlogicl composition of soil smples tken from test pits -, covering the centrl investigtions re, ws very homogeneous n order of bundnce, qurtz, plgioclse, -feldspr, mic, chlorite nd hornblende were typicl for the 2 mm frction, nd correspondingly illite, hornblende nd chlorite for the fine frction, ie 2 µm (intinen et l 200 eochemistry he soil chemistry ws nlysed from the test pits - he predominnt soilforming process in inlnd is podzoliztion of minerl soils igure illustrtes the structure nd horizons of podzol profile nd min processes he high moisture content, high incidence of nerobic conditions nd poor decomposbility of plnt litter hve resulted in grdul ccumultion of orgnic lyer comprising cidic, prtilly decomposed litter nd humus in the surfce lyer he composition of orgnic compounds vries widely, depending on the vegettion nd soil properties (rdy odzolic soils re chrcterized by light coloured eluvil horizon immeditely below the orgnic lyer, nd reddish illuvil horizon below tht he eluvil horizon hs been strongly leched by cid percoltion wter nd is low in bse ctions ron nd luminium re removed s colloids incorported by cly minerls or s orgnometllic complexes, minly in illuvil horizon odzolized till soils re heterogeneous in chemicl, minerlogicl nd physicl properties (ontio ähkönen odzolistion, the nturl cidifiction of soils, is slow process tht strted on the surficil prts of minerl soil fter eichselin glcition, bout yers go in inlnd (onner wing the evolution of ltic e, the oldest podzols re in supr-qutic res of northern nd estern inlnd t lkiluoto most of the podzol soil lyers re not well developed, becuse the youngest podzol soils ( re on the cost of ulf of othni, the re with the highest uplift rte in inlnd he lnd will rise bout 0 m during the next yers (öfmn he present rte of uplift in lkiluoto is bout mmy nd thus m during the next 000 yers (ronen et l

26 22 igure est pit 2 (igure by triin eskitlo, osiv 200 igure est pit (igure by triin eskitlo, osiv 200

27 2 n the innish soil conditions, the humic nd illuvil horizons of the podzol re especil importnce in the retention of pollution nd other hrmful substnces etention is most effective in fine-grined tills tht hve some permebility but in which the flow of wter is slow nd dissolved substnces hve time to rect with soil components (eikkinen 2000 he most importnt fctors ffecting wethering of soils re the susceptibility of minerls to wethering, grin size, climte, topogrphy nd runoff conditions he soil cn be considered s sink nd source of elements in which element concentrtions re much higher thn in soil solution phse tion exchnge on surfces of soil prticles is closely relted to wethering nd podzol process in the soil he min esily soluble exchngeble ctions re 2, g2,,, l nd n soil solution, the presence of hydrogen ions ctivtes ction exchnge rections between cly minerls, orgnic mtter nd root nodules tion exchnge on the surfces of soil prticles is the most importnt buffering process in humus nd eluvil horizon (rdy, ndersson igure tructure nd horizons of podzol profile podzol profile nd circultion of wter, b owing to electrolytes dissolved from the eluvil horizon, the p of the runoff wter increses in the illuvil horizon nd trnsition zone, precipitting luminium, iron nd silicon compounds, c ction exchnge is most intense in the humus nd eluvil horizons, nd the chemicl wethering of minerls in the trnsition zone nd wekly ltered prent mteril igure from ähkönen odified fter thler (0 nd Jcks et l ( he soil dt of test pits - is divided for two ctegories surfce minerl soil horizons nd 2 -horizon (bsl till urfce soil horizons consist of ltered soil lyers (eluvil, illuvil nd trnsition zone nd -horizon (bsl till under surfce soil horizons hs undergone only slight chnges if ny since the time -horizons were deposited (ble s result of wethering nd buffering processes, the p of the percoltion wter grdully increses s it psses through deeper horizons he gretest devitions in soil

28 2 p re due to the vrition in humus nd cly contents (äisänen he p vried from 0 to 0 in surfce soil lyers nd from to 0 in -horizon ter content nd orgnic mtter ptterns were quite similr both in surfce soil horizons nd bsl till he nion concentrtions (l,, leched by wter were extremely low or under detection limit n generl, chloride concentrtions re remrkble higher in more slty itorin-cly deposits thn in ncylus-clys in the costl res luoride rects lmost with ll inorgnic nd orgnic elements lso cly minerls cn contin substntil mounts of fluoride he solubility of fluoride is lowest when p is - (drino itrtes come to overburden from wet nd dry deposition, decomposition of nitrogenous orgnic mtter, fertilizers nd sewge concentrtions were clerly higher in -horizon (- mgkg thn in surfce soil horizons (- mgkg itric cid leched concentrtions were severl hundreds or thousnds times higher compred to synthetic rinwter lech concentrtions (ble n generl, concentrtions in underlying bsl till were highest for l, e, nd g by using nitric lech, wheres the concentrtions in underlying bsl till were in generlly highest for, nd r by using synthetic rinwter lech he most luminium is incorported into minerls, minly feldsprs, which re not redily dissolved by cids luminium goes into solution most esily when in cly minerls, chlorite, biotite nd depending on the degree of wethering, in mphiboles nd pyroxenes n generl, luminium is enriched in illuvil horizon luminium concentrtions were higher in surfce soil horizons thn in -horizon when using synthetic rinwter lech n strong nitric lech the medin vlue of luminium ws higher in surfce horizons, but the rnge of concentrtion ws higher in -horizon he iron-bering minerls wether esily n oxidizing conditions dissolved iron is precipitted s wter-bering mixture of hydroxides nd oxides, which my, give rise to sedimentry iron ores, lke nd bog ores, deep se concentrtions nd the illuvil horizon zone in podzol soils n the test pits of the lkiluoto re there were only observtions of iron enriched in illuvil horizon he concentrtions ptterns of the bse ctions nlysed with synthetic lech correlted with those of bse ctions soluble in nitric lech, lthough, due to the difference in strength of the lech, the concentrtion levels vried se ctions,, g,, (lkli nd erth lkli metls pools re expected to decrese in the future due to surfce soil wethering, leching nd removl of nutrients lcium is the most common lkline erth metl owever, the low bundnce of in innish bedrock reflects the predominnce of grnitoides, the redy wethering of clcium minerls nd their depletion in sediments n generl, clcium concentrtions incresed ccording the soil depths gnesium minerls wether quite esily, with dissolved mgnesium being removed from solution mostly into cly minerls nd crbontes gnesium concentrtions showed lmost similr ptter in surfce soil nd -horizon, lthough the rnge of mgnesium concentrtions ws higher in -horizons otssium feldsprs re resistnt ginst wethering issolved potssium is dsorbed from solutions onto colloids nd is enriched in clys n the surfce horizon the medin vlue of potssium lech by synthetic rinwter ws hlf of the vlue in -horizon odium-rich plgioclse is lso resistnt ginst wethering issolved sodium remins

29 2 in solutions in ion form nd is removed to the se, where it dds to the slinity he ptterns of sodium concentrtions were rther similr in surfce soil nd -horizons he regionl vrition in solubility of strontium is similr to sodium, clcium nd potssium, suggesting tht strontium minly incorported in plgioclse nd potssium feldsprs, which re highly resistnt to wethering cidity of soil increses the leching of strontium trontium concentrtions in surfce nd -horizon were low using the both leches he proportion of cid-extrctble strontium in the fine frction of till is of the totl strontium in innish soils (oljonen 2 ome of the urnium bering minerls re highly resistnt ginst wethering, where s some minerls eg ptite wether esily he mjor urnium deposits re found in sediments nd sedimentry rocks nd less importnt deposits in pegmtites nd hydrotherml veins lck shles form vst urnium reserves he verge urnium concentrtions in innish soils re round ppm using the totl dissolution (oljonen 2 n test pits the concentrtions of synthetic rinwter lech were low, but using nitric cid lech they were lmost sme or even higher thn in innish soils in verge rnium concentrtions were higher in surfce soil horizons thn in - horizons esium ores re ssocited with pegmtites contining rre elements, eg lithium nd beryllium esium migrtes in soils only slowly nd is redily dsorbed by colloids nd enriched in clyey sediments cid-extrble cesium concentrtions in innish soils vry from 0 to ppm (oljonen 2 n the test pits the synthetic rinwter lechble concentrtions were low, but in nitric cid lechble concentrtions were t the sme level s in innish soils in verge he min element concentrtions by depth of test pits re presented in nnexes -