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<br />Trace Element and Salt Movement in Retorted Oil Shale Disposal Sites'
<br />JOHN M. STARY. AND EDWARD F. REDENTE'
<br />ABSTRACT
<br />The direnioo •od amount of sail and Irau rlemenl movrmeor wishin
<br />Toned shale disposal piles is a mayor enrvonmeoW mourn. This study
<br />samines the rediszribulion of soluble salts and lrarc elements (AS, B,
<br />tl, Cu, F, Fe, Mn, Mo, Na, Ni, Pb, $e, and Znl in rcsoned shalt lest
<br />:ats wish differeol sopsuil trcarmenls 6 yr deer coostrudioo. Topsoil
<br />catments induded oo topsoil, oa IopsoO and leached wish 76rm water,
<br />)rm topsoil, 60-cm topsoil, 90-cm wpso0, 60-cm topsoil and mpiaary
<br />.trier, and a disturbed soil control (no resorted shaleJ• Soluble salts
<br />specially Na salsa) and F showed considenblc movement both up-
<br />ardsand downwards in she profiles. Molybdenum showed some more-
<br />irnl in both directions. Thr remaining elements sbowed little or no
<br />~orement out of sbe shale layer. Increasing topsoil depths usulted in
<br />ss salt or trau element movement in either dircclioo. Use of a ~pillary
<br />artier between she topsoil ^od resorted shalt prcremed upward mign-
<br />on of sales and trace elements. Aher 6 yr the exposed shdc rrcarmen6
<br />path leached and unleashed) consinutd to have considerably higher
<br />,II and Ince element coolrols than any other Ircalmrnl. Bemuse of
<br />roiled roosiog depths, deeper peredlasioo of moisture is occurring on
<br />loss containing retorted shale Ihan on the control plot.
<br />Additional /oiler IPOrdr: reclamation, leaching, capillary rise, soil
<br />d h.
<br />tile, J A1., and LF. Rcdcntn. 1986. Trau dcmrnt and soh move
<br />.m in rezoned oil shale sites. J. Environ. Qual. 15:282-Z68.
<br />(EC) averaged 14.0 and 7.0 dS m", rrsptaivtly. 71a gr11C-, ;
<br />treatments used were az follows:
<br />I. Exposed retorted shale (no topsoil),
<br />2. JO cm of topsoil over rezoned shale,
<br />3. 60 cm of topsoil over retorted shale,
<br />4. 90 cm of topsoil over rezoned shale,
<br />5. 60 cm of topsoil over a 30-cm rock npillar7 boas ew
<br />retorted shale, and
<br />6. a control consisting o(disturbeA soil with tyo rmr~;auk
<br />(vegetation removed and soil ripped to 30 ®}
<br />The six plots, n)eazuring 2J by 109 m, were r~:s --'saer~
<br />side bu[ topsorl treasmentt were arranged in a rauiom adcm,wti:
<br />confounding treatment effects with landsnpc pwitice 1¢aC10
<br />Lion to the sin topsoil ueatmenu listed above, a soars aYataa
<br />was creased in Augua of 1981 by leaching a poem or tae epo,
<br />ed shale pile with 76 em of wrier. Leaching war ~;_+~*^a~b~
<br />sprinkler irrigating she plot with 12 ro Il rm of •ata m o¢af'
<br />six consecutive nights. The seven trntmems mnssdaaf ra rAs neat
<br />art summarized in Fig. 1.
<br />lmmtdiarely following construction of the plow, the area nap
<br />fersilized wish N and P, and drill seeded with diserx emxaagaf!
<br />native and insroduced grass, forb, and shrub spein
<br />In Auguss of 1963, soil pits were dug in cash of tf<fesa lyaa;
<br />and the profiles were intensively sampled so a drtxa u! J a s'
<br />bedrock, whichever came fast. Soil and rezoned shale saospfm+alp
<br />analyzed for As, Cd, Cu, Fe, Mn, Mo, Ni, Po, Sc+mtDa
<br />N H.HCO,-DTPA extracts by inductively couplal plazmsaoar~
<br />emission spenroscopy {ICP-AES) (Soltanpour n al., W:'i}astfb
<br />water soluble D and F m saturation extracts by ICP-AES tSat:av
<br />pour ez al., 1982). Electriral conducuviurs and S4R ra¢e thnJ®
<br />mined in saturation extracts (U.S. Balmily Laboratory StarC :%y.
<br />hr problems encountered in reclaiming retorted oil shale
<br />:r generally associated with its high trace element and
<br />.JI contem (Redente et al., 1980). Two primary concerns
<br />e that trace elements and salts in buried retorted shale
<br />.ill migrate toward the soil surface, either by diffusion
<br />r capillary action, and prevent adequate plant establish-
<br />lent, or that they will be leeched downward out of the
<br />:ofile and evemually contaminate groundwater supplies
<br />:larbert et al., 1979; Wlldung and Zachara, 1980). This
<br />tidy was imlialed to determine the extern of soh and
<br />ace elemem movrmrnt within seven differeol soil
<br />.sorted shale disposal piles alter 6 yr in the field.
<br />METHODS AND MATERIALS
<br />the study sire is locarcd in the Piceance Basin of non hwest Col-
<br />: ado. Thr elevation a 2020 m, mean annual trmperamre is 6.8 `C,
<br />:d mean annual preapitanon Is 28 2 cm (wuh about hall occurr
<br />.; as snowfall) The prtdommam soil Iy pe m the area Is 1'amac
<br />.am (fine-loamy, mixed, Dorollic Cambonhids), which wppons
<br />big sagebrush (Arlemisia lridenlmo var. rndenmm) community
<br />In the summer of 1977, six differem plots were constr ucled b}'
<br />!ling pits with a 60-cm layer of retorted oil shale and covering
<br />nh vanous thicknesses of topsoil and a capillary bar nrr. The
<br />Toned shale used in this study was Paraho (direct mode process)
<br />Tuned shale from the Anvil Poims rezoning facility near Rtfle,
<br />U. The texmrc was gravelly sandy loam. The pH, ah hough in-
<br />..illy as high as 12.2, dropped to 9 6 within a few months in zhc
<br />cld. Sodium adsorption ratio (SAR) and elMrical conduaivisy
<br />' This study was funded by the U.5 Dep. of Gnergy under Contract
<br />UC AC02-7fiE V09018. Rccri veil 71 July 7985.
<br />'Research Associate and .4ssoamr Professor, res pea ivrly. Runge
<br />n nn' Urp., C'uloredo Seta Uuiv., run Collins, Ctl 805:7
<br />RESULTS AND DISCUSSlOi\
<br />During the following discussion, it should bettctat7tg
<br />this study deals with a retorted shale layer (yl}.m ~
<br />Retorted shale piles constructed during commar::ricpca
<br />Lions will be many times this thick and may reJeue coca
<br />greater quamities of trace elements and sale.
<br />Figures 2 to 4 show the disuibwion of EC, 543,.xr:,,
<br />F, As, and H within profiles from each o(the snot TM",
<br />The comrol treat mein, since it was only dial uebat Rr s
<br />depth of 30 cm, shows the natural disuibuuocsd.s:d;
<br />and trace elements in the subsoil. In some ass sin a
<br />trace element distnbutions in profiles containicg rCs:rtr6
<br />shale appear to be approaching those in the md¢t:ilni.
<br />In other cases, however, the presence of rctoreuf tQtk
<br />continues to have a profound influence oo dis[rLtwea
<br />pauerns.
<br />Figure 2 shows that in every profile, Na' aav! stnrCae
<br />salts have been leached out of the upper ponied al ~
<br />shale layer. let fact, the upper poniotu o(thesaaieSgecn
<br />in the 30, t`A, and 90 cm, topsoil treatments alxltaQy lac
<br />lower SAR values than topsoil layers immediatdlla.a~y.~
<br />ing them. These distribution patterns are proumahlta
<br />result of leaching action; however, there also apgary
<br />be some inter (ace effects occurring. The abrupttemCOs
<br />change at the soil-shale interface (loam tograveB7 sine
<br />loam) maybe causing water, carrying Na' and dyer trm
<br />bee ions, to accumulate just above the shale faps_Es
<br />traction of this soil moisture by plant roots .odhS tlJs
<br />result in concentration of Na' and other sotuhle ,mss
<br />
<br />_ I •r
<br />to
<br />pouruls az this <I
<br />Qmnt: io the 5 [O
<br />dk~ncS that this
<br />t¢ata:umtrlate. U
<br />(+YLewiao may a
<br />§lucs to product
<br />E]f the trace
<br />a[wvnr. prfhal)~
<br />IwCinuion brcat
<br />Q19`+S) found 1h.
<br />spoils: kachatrs c
<br />~ltimr::ards for dri
<br />Can been eonslde
<br />j s6hL9 Ihr stvr;
<br />mmu u nyosl of
<br />FSu.;rtnc has ac..
<br />,,,;,7,. L~tcriacrs ..
<br />of the shalt lay,
<br />n;-:.-r. wpioil tit
<br />dc.ciop~d. This
<br />rc ;erm~ o (the I )~
<br />wJ capillary
<br />arapotrarupiral i.
<br />sorer through ih,
<br />xrfu6k constinsc.
<br />~(rJi[f CJI1Crnir.
<br />[rt~z. When real
<br />Lttf pfZDl f00(5 (s
<br />:poi [ht shalt) eel
<br />llc abate layers.
<br />leer_s. ^th.Ie moist m
<br />(~ ~`V"~ aCl Ic
<br />~ s..x4-shale intr
<br />wrdu F and SA N
<br />tit solubilities be
<br />prmcn[.
<br />1loiybdcnum
<br />the profiles (Fig.
<br />~ v ~ Cnl Of SOI
<br />.iv-, ..i approxtll
<br />.I. Lim iron Ouul t'ol. 15, nn. 3. 17X6
<br />
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