Mine als 2011, 1, 73-108; doi:10.3390/min1010073
mine als
ISSN 2075-163X
www.mdpi.com/jou nal/mine als/
A icle
Assessing Soil Quali y in A eas A ec ed by Sul ide Mining.
Applica ion o Soils in he Ibe ian Py i e Bel (SW Spain)
Isabel González *, Emilio Galán and An onio Rome o
Depa men o C ys allog aphy, Mine alogy and Ag icul u al Chemis y, Uni e si y o Se ille,
Apdo. 553, Se ille 41071, Spain; E-Mails: [email protected] (E.G.); [email p o ec ed] (A.R.)
* Au ho o whom co espondence should be add essed; E-Mail: [email p o ec ed];
Tel.: +34-954-556-318; Fax: +34-954-557-140.
Recei ed: 1 Sep embe 2011; in e ised o m: 21 Oc obe 2011 / Accep ed: 25 Oc obe 2011 /
Published: 7 No embe 2011
Abs ac : The cha ac e iza ion, e alua ion and emedia ion o pollu ed soils is one o he
p esen en i onmen al challenges o be add essed in he coming yea s. The o igin o ace
elemen s in soils can be ei he geogenic o an h opogenic, bu only he la e is in e es ing
om a legal poin o iew. The haza d o he pollu an s in he soils no only depends on
hei o al concen a ion, bu pa icula ly on hei a ailabili y. The mobili y o he ace
elemen s depends on hei specia ion, and i is also a ec ed by se e al soil pa ame e s.
Mining ac i i y is one o he mos impo an an h opogenic causes o soil pollu ion. As a
case s udy, his wo k is ocused in he Rio in o mining a ea (Ibe ian Py i e Bel , IPB, SW
Spain). The IPB is one o he mos impo an me allogenic p o inces in he wo ld and i
has been exploi ed o housands o yea s. The disposal o mining esidues has p oduced
impo an sou ces o con amina ion by ace elemen s and acidic wa e s a ec ing soils and
i e s. In addi ion o hese p oblems, he closu e o mines in he Py i e Bel a he end o
he 20 h Cen u y has led o a g ea loss o employmen , which has caused he de elopmen
o an in ensi e ag icul u e o ci us ui s as a new sou ce o income. The in ensi e
g owing o ci us ui s and he adi ional subsis ence ag icul u e ha e been de eloped
su ounding he mining a eas and on loodplains nea o mining si es. The le el o soil
pollu ion has no been aken in o accoun in hese cases, no has i s impac on he heal h o
he inhabi an s o hese a eas. The e o e, i is o g ea in e es o s udy he cu en s a e o
he cul i a ed soils and he sou ces and ypes o con aminan s de i ed om mining ac i i y
in o de o p og am i s decon amina ion, whe e app op ia e, acco ding o legisla ion. In
o de o know he p esen and u u e haza d posed by he soils chemical and mine alogical
specia ion has been ca ied ou , gi en ha he a ailabili y o a me al depends on he phase
OPEN ACCESS
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in which i is ound. The esul s showed ha mining ac i i y has caused high le els o As,
Cu, Pb and Zn in se e al cul i a ed soils. Mo eo e , Cu, Pb and Zn showed a high
bioa ailabili y. This sugges s ha a leas o he s udies a e necessa y o p ese e heal h in
he inhabi an s o his a ea. The me hodology ca ied ou in his wo k allowed o selec
po en ially pollu ed a eas whe e ag icul u al ac i i ies a e no ecommended.
Keywo ds: soil con amina ion; ace elemen s; sul ide mining; Ibe ian Py i e Bel
1. In oduc ion
1.1. Con amina ion and Con aminan s
The p esence o ha m ul concen a ions o some chemical elemen s and compounds in soil is a
special ype o deg ada ion known as con amina ion. Con aminan s a e always ound in anomalous
(highe han usual) concen a ions and gene ally ha e a ha m ul impac on some o ganisms. The o igin
o con aminan s is ei he geogenic i hey come om soil pa en ocks, olcanic ac i i y o mine al
leaching, o an h opogenic i hey come om haza dous indus ial was e, ag icul u al o mining
ac i i ies, o u ban solid was e om households. Howe e , an h opogenic con aminan s a e he only
ones legally conside ed as ue con aminan s.
The oxici y o a chemical elemen o compound is i s abili y o ad e sely a ec biological
unc ions. Wi h he only excep ion o oxins (which a e biogenic), oxic compounds and ma e ials ha e
a non-biological o igin.
Con aminan s a e mobilized by physical, chemical and biological ec o s. They can lea e soil by
ola iliza ion, dissolu ion, leaching o e osion and en e o ganisms when hey a e in a bioa ailable
( ela i ely soluble) o m. Thus, he po en ial o an elemen ––whe he a con aminan o
o he wise––passing om soil in o i s solu ion is known as “a ailabili y”. The mo e speci ic e m
bioa ailabili y is he deg ee o which a con aminan in a po en ial sou ce is ee o up ake (mo emen
in o o on o an o ganism) [1]. Usually, only a small ac ion o each po en ially con amina ing
subs ance in a medium is bioa ailable. Al hough con aminan s a e gene ally noxious, some may be
ha mless o speci ic o ganisms.
Bioa ailabili y is a unc ion o (a) he speci ic physical and chemical o m in which an elemen o
subs ance occu s, and (b) he abili y o o ganisms o abso b o inges i . Bioa ailable elemen s can be
accumula ed in an o ganism (i.e., bioaccumula ion) a concen a ions up o 3–5 o de s o magni ude
highe han hose in hei medium.
1.2. Hea y Me als and T ace Elemen s
The pe iodic able includes abou 70 me als, 59 o which a e hea y me als (i.e., me als wi h an
a omic weigh exceeding he weigh o i on, which is 55.85 g/mol). This de ini ion excludes me als
wi h a lowe a omic weigh , which howe e can also include con aminan s. Such is he case o V, Mn
and C , which ha e an a omic weigh o 50.95, 54.44 and 52.01 g/mol, espec i ely. I also happens
wi h o he non-me al elemen s such as As, F and P. The e o e i is mo e accu a e o e e o hem as
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ace elemen s, e en hough mos ino ganic con aminan s a e in ac hea y me als. Occasionally, soil is
con amina ed wi h high concen a ions o majo elemen s such as Na, Fe o Al.
T ace elemen s a e p esen a low concen a ions (mg⋅kg−1) in he ea h c us , soils and plan s. Many
o hem (Table 1 [2]) a e essen ial o plan , animal and human g ow h, bu can be oxic abo e ce ain
concen a ion le els. As a ule, ace elemen s a e oxic i inhaled o inges ed in la ge quan i ies and
o e a long pe iod o ime. Fo example, he de iciency and oxici y h esholds o Se, F and Mo di e
om one ano he only by a ew pa s-pe -million (ppm) [3].
Table 1. Mic onu ien s and mac onu ien s o op imum wo king o li e o ganisms
(collec ed om di e en sou ces by Siegel [2]).
T ace elemen s ha a e essen ial
mic onu ien s
(a ew mg o µg/day)
As, Co, C , Cu, Fe, Mn, Mo, Se, V, Zn
O he essen ial mic onu ien s F, I, Si
Mac onu ien s
(100 mg o mo e pe day) Ca, Cl, Mg, P, K, Na, S
Non-essen ial ace elemen s * Be, Cd, Hg, (Ni), Pb, Sb, (Sn), Ti
* Me als in b acke s can be essen ial.
Mos o ace elemen s in soil can be classi ied in i e g oups acco ding o hei chemical o m in
soil solu ion, namely: ca ions (Ag+, Cd2+, Co2+, C 3+, Cu2+, Hg2+, Ni2+, Pb2+, Zn2+), na i e me als (Hg,
V), oxianions (AsO43−, C O42−, HSeO3−, SeO42−), halides (F−, B −, I−) and o ganome als (Ag, As, Hg,
Se, Te, Tl). These g oups a e no mu ually exclusi e and, in ac , some ace elemen s can all in o
mo e han one. Typically, he concen a ions o C , Ni, Pb and Zn in soil ange om 1 o 1500 mg⋅kg−1;
hose o Co, Cu and As om 0.1 o 250 mg⋅kg−1; and hose o Cd and Hg om 0.01 o 2 mg⋅kg−1 [4].
Table 2 lis s o he usual and anomalous geochemical concen a ions o a a ie y o elemen s [5].
Table 2. No mal and anomalous geochemical concen a ions o se e al ace elemen s
in soils [5].
Elemen No mal ange (mg/kg) Anomalous concen a ions (mg/kg)
As <5–40 Up o 2,500
Cd <1–2 Up o 30
Cu 2–60 Up o 2,000
Mo <1–5 10–100
Ni 2–100 Up o 8,000
Pb 10–150 10000 o mo e
Se <1–2 Up o 500
Zn 25–200 10,000 o mo e
F om all o he ace elemen s ound in soil, he ollowing 17 a e especially oxic and a ailable a
concen a ions exceeding oxic le els: Ag, As, Bi, Cd, Co, Cu, Hg, Ni, Pb, Pd, P , Sb, Se, Sn, Te, Tl
and Zn. Ten o hem (Ag, As, Cd, Cu, Hg, Ni, Pb, Sb, Sn and Tl) a e eadily mobilized in
concen a ions exceeding conside ably hei geological le els due o human ac i i ies [6]. The la es
US En i onmen al P o ec ion Agency (EPA) lis o p io i y pollu an s includes he ollowing 13 ace
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elemen s: Sb, As, Cd, C , Cu, Hg, Ni, Ag, Pb, Se, Tl, Zn and Be, which was no included in
p e ious lis s.
1.3. Pu i ying Powe o Soil
Soil usually ac s as a p o ec i e ba ie o mo e sensi i e media such as wa e and o ganisms by
il e ing, decomposing, neu alizing o s o ing con aminan s. Hence i subs an ially educes hei
bioa ailabili y. The pu i ying abili y o soil depends on i s con en s in o ganic ma e , ca bona es, and
Fe and Mn oxyhyd oxides, as well as on i s clay con en and mine alogical composi ion, ca ion
exchange capaci y, pH, Eh, ex u e, pe meabili y and mic obial ac i i y. The e o e, he pu i ying
powe o soil has a limi o each subs ance. I his limi is exceeded, he soil becomes con amina ed
and is a sou ce o con amina ion.
The load capaci y o soil shows i s abili y o con ol he ad e se impac s o con aminan s and ende
hem inac i e o ha mless. Cheng e al. [7] p oposed he Load Capaci y o Ag icul u al Soils o Hea y
Me als (LCASHM), which depends on soil p ope ies, he ype and con amina ion his o y, he p esence
o oxici y indica o s and a ious en i onmen al pa ame e s.
1.4. The O igin o T ace Elemen s in Soil
T ace elemen s p esen in soil can be geogenic o an h opogenic. The p esence o he o me is
la gely de e mined by hei geoa ailabili y, which is ha po ion o he o al con en o a chemical
elemen o a compound in an ea h ma e ial ha can be libe a ed o he su icial o nea -su ace
en i onmen (o biosphe e) h ough mechanical, chemical, o biological p ocesses [8].
Geoa ailable ace elemen s ypically each he soil when hey a e eleased om hei pa en ock
because o wea he ing. Toge he wi h me als om olcanic emissions and mine al leacha es, hey
cons i u e he so-called “geogenic me als”. The ease wi h which ace elemen s can be eleased om
hei pa en ock depends on he s uc u e and he he modynamic s abili y o he ock o ming
mine als. Thus, highly polyme ized s uc u es a e especially s able and esis an o des uc ion, and
hei s abili y dec eases acco ding o he ollowing sequence o a omic bonds: Si–O > Al–O > X–O.
The amoun o geoa ailable elemen s eleased om ocks in o soil is negligible compa ed o hose
o an h opogenic o igin. Wea he ing causes ace elemen s o concen a e in soil, bu usually a le els
below hei oxic h esholds. E en i hese le els a e exceeded, he e will be almos no isk o oxici y
due o high s abili y and he low a ailabili y o hese me als in soil.
Ul abasic ocks can con ain la ge amoun s o some ace elemen s such as C , Ni, Cu o Mn. On
he o he hand, acid igneous ocks and sedimen a y ocks (sands one and limes one) con ain e y small
amoun s o hem. The highes le els o ace me als in soils––inhe i ed om he pa en ock––a e
ypically hose o C , Mn and Ni, ollowed by Co, Cu, Zn and Pb, and, a beyond As, Cd and Hg,
which a e usually p esen a e y low concen a ions.
Anomalous high concen a ions o ace elemen s in soil usually come om me al o es (sul ides,
oxides). Me al mining and ex ac ion p oduce ons o was e each yea ; mos o i con ains py i e and
o he sul ides whose oxida ion eleases a la ge amoun o ace elemen s in o he en i onmen ,
especially in o soils. The uppe laye s o soil a ound mining and ex ac ion a eas can con ain high
concen a ions o Cu, Ni, As, Se, Cd o Fe among o he elemen s, depending on he pa icula o e.
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T ace elemen s in soil can come om a ious o he an h opogenic ac i i ies in addi ion o
mining, namely:
• Fa ming (i iga ion, ino ganic e ilize s, pes icides, manu e, liming amendmen s and,
especially, sewage sludge).
• Elec ical powe p oduc ion. Coal bu ning is one o he p ima y sou ces o me al deposi ion in
soil. Fo example, he mal powe plan s ypically elease Pb, Ni and V con ained in oil.
• Indus ial ac i i ies (pa icula ly i on and s eel making ac o ies, which elease me als
con ained in Fe and Ni o es). Hea y indus ial a eas a e ypical sou ces o As, Cd, C , Hg, Fe,
Ni, Pb and Zn.
• Household ac i i ies. Roughly 10% o all household was e consis s o me als. The e o e, i s
bu ial can lead o he con amina ion o g oundwa e and i s ashing o a mosphe ic
con amina ion wi h ola ile me als and hei subsequen inco po a ion in o soil.
2. Soil Con amina ion by T ace Elemen s
2.1. Physical S a e and Rela i e A ailabili y o Soil Con aminan s
Con aminan s in soil and sedimen s can be p esen in six di e en o ms, namely [9]: pa icles
(pa icula e con aminan s), liquid ilms, adso bed, abso bed, and solids o dissol ed ma e in po e
wa e . The beha io o a con aminan in soil depends on i s pa icula o m. As a esul , o al
concen a ion o ace elemen s in soil may ep esen hei po en ial oxici y in ela ion o ag eed
h esholds, bu no an ac ual isk. The e o e, he accu a e assessmen o hei oxici y equi es
de e mining no only hei concen a ions, bu also hei physical and chemical o ms, as well as hei
a ailabili y, which p o ides a di ec measu e o hei ac ual haza dousness. Las ly oxici y o ace
elemen concen a ion in he soil should also be es ed agains some speci ic o ganisms. Ne e heless
he ease wi h which a po en ially oxic subs ance can en e he ood chain om soil depends on
whe he he me al is in ee o m in he in e s i ial solu ion o in solid o m, and also on he way he
me al is bound o soil pa icles and on i s speci ic chemical o m (i.e., i s specia ion). Acco ding o
Kaba a-Pendias [10], how s ongly a me al is e ained by soil condi ions dic a es i s ela i e a ailabili y
o plan s and hence he isk o i s eaching o ganisms (Table 3).
Table 3. Rela i e mobili y and phy oa ailabili y o me als species in soils.
Me al species and associa ion A ailabili y-mobili y
Simple o complex ca ions in solu ion phase Easy
Exchangeable ca ions Medium
Chela ed ca ions Sligh
Me als adso bed by soil pa icles Sligh
Me al compounds p ecipi a ed on soil pa icles A ailable a e dissolu ion
Me al bound o ixed inside o ganic subs ances A ailable a e decomposi ion
Me al bound o ixed inside mine al pa icles A ailable a e wea he ing and/o decomposi ion

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2.2. Con aminan Mobili y in Rela ion o Soil Pa ame e s
The mobili y o a me al depends no only on i s chemical specia ion, bu also on a ious soil- ela ed
pa ame e s such as pH, o ganic ma e , ca bona es and clay mine als. Thus, no all he exchange
ca ions a e equally a ailable; a he , hei a ailabili y depends on he pa icula mine als con aining
hem in he exchange complex. Fo example, me als ound in smec i e o illi e do no necessa ily
beha e iden ically. Also, i he me al is ound in i s p ecipi a ed o m, he e is no eason why i has o
beha e iden ically, whe he i is in a ca bona e, sul a e o phospha e. Likewise, me als in
sul ides—which a e ela i ely easily oxidized and dissol ed––will usually beha e di e en ly om
me als in silica es, which a e i ually s able in any medium.
Usually ace elemen s show a e y low mobili y and accumula e wi hin he op ew cen ime e s o
soil as a esul . The e o e hey a e leached in e y small amoun s o he lowe ho izons. Hence an
an h opogenic me al p esen a high concen a ions in he uppe soil ho izon will usually be a much
lowe le els in deepe laye s. Howe e , his beha io is addi ionally dependen on he p ope ies o he
pa icula soil. The ollowing soil a iables a e c ucial wi h a iew o assessing he sensi i i y o soil o
con aminan agg essions:
• pH. Mos me als end o be mo e eadily a ailable in acid media, whe e hey a e less s ongly
adso bed. As an excep ion, As, Mo, Se and C a e mo e mobile in alkaline media.
• Tex u e. Clayey soils a e highly e ec i e in e aining me als by adso p ion (o in hei
exchange complex o clay mine als). On he o he hand, sandy soils a e unable o ix me als,
which can hus easily each he wa e able.
• Clay mine als. Clay mine als di e in speci ic su ace a ea and elec ical cha ge. Thus, he
highe he speci ic su ace a ea o a silica e is, he highe i s abili y o adso b me als [11].
Howe e , abso p ion by clay mine als is negligible in soils con aining la ge amoun s o o ganic
ma e and/o i on oxyhyd oxides which a e mo e e ec i e in his espec [12].
• O ganic ma e eac s wi h me als o o m exchange complexes o chela es. Me als can be
adso bed o he ex en o being s abilized as a esul (Cu) o o m highly s able chela es wi h
o ganic ma e (Pb, Zn).
• Ca ion exchange capaci y. The ca ion exchange capaci y o soil depends on he clay mine als,
o ganic ma e , and alence and hyd a ed ionic adius o he me al. The g ea e he adius and
lowe he alence a e, he less s ongly he me al will be e ained.
• Redox po en ial. The edox po en ial dic a es whe he he me al is p esen in oxidized o
educed o m. Eh–pH plo s p o ide in o ma ion abou he s abili y o me al compounds and i
is a con enien me hod o p edic ing he esponse o ace elemen s o a change in
en i onmen al condi ions.
• Ca bona es. The p esence o ca bona es acili a es p ese a ion o a highly alkaline medium
and hence p ecipi a ion o ace elemen s. Also, Cd and o he me als end o be abso bed
by ca bona es.
• I on and manganese oxides and hyd oxides. They a e inely sp ead ac oss soil and hence hey
a e highly ac i e. Thei low c ys allini y and small pa icle size make hem highly so p i e o
di alen me als especially Cu and Pb, and, o a lesse ex en , Zn, Co, C , Mo, Ni and As.
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• Salini y. An inc eased salini y can esul in he mobiliza ion and e en ion o ace elemen s ia
wo di e en mechanisms. Fi s , Na and K can eplace me als a ca ion exchange si es, and hen
chlo ide and sul a e ions can o m mo e s able compounds wi h p e iously eleased me als such
as Pb, Zn, Cu and Hg. The sal s usually make soil alkaline.
2.3. Assessing he Haza dousness o Me als in Soil
The haza dousness (mobili y and a ailabili y) o a con aminan can be assessed by using a ious
chemical and mine alogical p ocedu es. Whe he a gi en elemen o compound is p esen in a
wa e -soluble phase––and hence eadily a ailable o be ans e ed o a plan o li ing o ganism––can
be checked by assessing i s mobili y ia i s wa e solubili y. This p ocess equi es he ex ac ion o
happen wi h neu al o sligh ly acidic wa e .
Ano he way o assessing he ans e abili y o me als (pa icula ly di alen ca ions) o plan s is
ex ac ing soil wi h DTPA o 0.05 M EDTA a pH 7 [13]. The e is a wide consensus abou he ac ha
his p ocess p o ides qui e an accu a e measu e o he amoun o me al ha plan s can abso b om soil
unde egula condi ions [14].
These simple me hods can only be used o disc imina e be ween esidual me al and me al ex ac ed
by wa e o a mild o ganic sol en . Howe e he e a e mo e elabo a ed me hods in ol ing sequen ial
chemical ex ac ions o ca y ou specia ion o elemen s in soil (i.e., ope a ional specia ion). Also
chemical specia ion is used o disc imina e be ween oxida ion s a es o an elemen , and unc ional
specia ion, which dis inguishes be ween molecula o ms. The plan a ailable ac ion o an elemen in
soil depends on i s chemical and unc ional specia ion (i.e., o i s dis ibu ion among i s di e en
species and chemical o ms).
Ope a ional specia ion, which is o en e e ed o as simply “specia ion”, is he mos equen choice
o soils because i is he simples analy ically and can be i ually implemen ed in any labo a o y wi h
usual a ailable means. Howe e , p ope specia ion equi es de e mining he o al concen a ion o each
me al and i s di e en chemical species. The selec i i y o each me hod used o his pu pose depends
la gely on how as he o ma ion and dissocia ion eac ions o he a ge species occu . Roughly,
classical p ocedu es used in his con ex ha isola e and examine each cons i uen sepa a ely, a e
subjec o wo majo sho comings, namely: (a) comple e isola ion is e y di icul o e en impossible;
and (b) he p ope ies o a componen in a complex mix u e a e no addi i e owing o he many
in e ac ions i can ha e wi h o he componen s.
Sequen ial ex ac ions do no allow us o comple e ull specia ion p ocesses bu hey can be use ul
o cha ac e ize he beha io o a con amina ing elemen as hey allow i s con en in he ac ion
associa ed o each soil componen ela ed o i s mobili y and ans e abili y o li ing o ganisms. In
summa y, sequen ial ex ac ion p ocedu es can p o ide ough es ima es o he dis ibu ion o ace
elemen s in di e en soil phases and hei ela i e mobili y.
Sequen ial ex ac ion p ocedu es ha e been a ound o a leas ou decades. Du ing ha ime hey
ha e been con inuously modi ied and upda ed, o e en eplaced wi h o he s p ocedu es p o iding us
wi h imp o ed esul s abou speci ic elemen s and soil phases. Hall e al. [15] e iewed he mos
widely used specia ion sequences o me als in soils and sedimen s. The p ocedu e essen ially in ol es
ob aining a ious consecu i e ac ions by ex ac ing p ocedu es wi h di e en sol en s o de e mine
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he dis ibu ion o ace elemen s in a solid sample be ween i s cons i uen phases. Such a dis ibu ion
is usually called pa i ioning. López Julián and Mandado [16] c i ically e iewed a ailable specia ion
me hods o his kind and hei ope a ional p o ocols.
One o he mos popula p o ocols was ini ially p oposed by Tessie e al. [17]. I has been he
subjec o a numbe o a ia ions [18-21]. B ie ly, he p ocedu e is as ollows: ac ions 1 o 3 (F1–F3)
a e he esul s o ex ac ion wi h ammonium ace a e, a educ i e solu ion made o hyd oxylamine
hyd ochlo ide in ace ic acid, and hyd ogen pe oxide in a ni ic medium, espec i ely, whe eas
ac ion 4 (F4) is he insoluble esidue emaining a e he h ee ex ac ions (Table 4).
Table 4. Sequen ial ex ac ion scheme o assessmen o pa i ioning o me als in
sedimen s gi en by Tessie e al. [17] and modi ied by Galán e al. [21].
F ac ion P ocedu e
Acid (F1) NH4Ac 1 M (35 mL), pH 5, 1 h, 20 °C, con inuous shaking (40 pm)
Reducing (F2) NH2OH.HCl 0.4 M in ace ic acid 25% (20 mL), 6 h, 96 °C, manual shaking
e e y 30 min.
Oxidan (F3)
HNO3 0.2 M (3 mL) + H2O2 30% (5 mL), pH 2 wi h HNO3, 2 h, 85 °C,
manual shaking e e y 30 min.; add H2O2 30% (3mL), pH 2 wi h HNO3,
3 h, 85 °C, NH4OAc 3.2 M (5mL) / in HNO3 dilu ed in 20 ml wi h H2O2,
30 min., 20 °C, con inuous shaking (40 pm)
Residue (F4) HF/HNO3/HCl 10/3/2.5 (20 mL), 2 h o d y
F1 con ains me als in he exchange complex and hose o ming o being abso bed in ca bona es.
The ea men used o ob ain his ac ion in ol es wo s eps: ex ac ion wi h 1 M MgCl2 o 1 h o
sepa a e exchangeable ca ions (i.e., hose which can be eplaced wi h o he mo e compe i i e ca ions in
clay mine als, amo phous ma e ials, e c.) and ex ac ion wi h sodium ace a e-ace ic acid a pH 5 o 5 h
o a ack ca bona es. F2 con ains me als in educible compounds (Mn oxides, and amo phous o
low-c ys alline Fe- and, occasionally, also Al-hyd oxides). F3 is he oxidizable phase and con ains
o ganically bound (complexed, adso bed and chela ed) ca ions in addi ion o some sul ides. Finally,
he esidual ac ion (F4) con ains me als in he mine al s uc u e o each ex ac ion- esis an mine al.
O e all, he pe o mance o sequen ial ex ac ion p ocedu es is limi ed by ac o s such as (a) he
selec i i y o he eagen s, (b) po en ial edis ibu ion (o e-adso p ion) o elemen s, (c) he
expe imen al condi ions used and (d) a sca ci y o e e ence ma e ials, which o en p e en s alida ion
and p ecision assessmen .
A numbe o ex ac an s a e no ully selec i e o some me als p esen in speci ic geochemical
phases. Such is he case o soil con aining la ge amoun s o i on hyd ous oxides, which equi e
epea ing hei ex ac ion wi h hyd oxylamine hyd ochlo ide se e al imes. Al e ing he pH o ensu e
ha all me als associa ed o he a ge phases will be comple ely eleased [20,21] is also needed.
In summa y, sequen ial ex ac ion p o ocols should be used wi h g ea cau ion, bo h when selec ing
he speci ic scheme o be applied and when in e p e ing he esul s. Some o he mos impo an c i e ia
o alida ing an analy ical me hod (e.g., i s heo e ical backg ound, c oss- alida ion wi h o he
echniques and sample-independence o he esul s) canno be applied o hese p ocedu es, which
p ecludes alida ion o hei ope a ional esul s. Howe e , hey a e bound o con inue in use,
cons an ly being imp o ed and upda ed, un il a uni e sally accep ed s anda d p o ocol is de eloped.
Mine als 2011, 1
81
I will happen his way because he in o ma ion hey p o ide abou dis ibu ions bea s a di ec
ela ionship o he geochemical beha io and he bioa ailabili y o chemical elemen s in na u e [22].
Cu en ly, analyses o en include a mine alogical s udy o he ac ions ob ained om each
ex ac ion. This no only shows us he pa icula elemen s eleased, bu also he speci ic mine als
dissol ed by each ex ac an , o be known, i.e., chemical-mine alogical specia ion. Dold and Fon bo é
and Dold [23,24], de eloped a specia ion scheme adap ed o sul ide mining esidues which in ol es
six s eps and mine alogical analysis o each ex ac in ela ion o he mine alogical composi ion o
he sample.
Indi ec and semi-di ec me hods o cha ac e izing solid phases by in a ed, X- ay luo escence
spec ome y o ene gy dispe si e spec ome y a e being supe seded by di ec specia ion me hods
based on mo e sophis ica ed echniques such as X- ay pho oelec on spec oscopy (XPS), ex ended
X- ay abso p ion ine s uc u e spec oscopy (XANES), X- ay abso p ion nea -edge s uc u e
spec oscopy (XAF) o X- ay abso p ion spec oscopy (XAS), all o which a o d comple e chemical
specia ion [25,26]. These echniques p o ide a mo e p ecise desc ip ion o p ocesses abou solid
su aces, whe he c ys alline o no , and chemical species a a omic le el. Howe e , some analyses
equi e using a synch o on, which is usually inaccessible o many labo a o ies. Also, he ou ine
wo k needed o p ocess hund eds o samples makes hese al e na i e p ocedu es a he slow and
expensi e unless hey a e used o de e mine a single elemen .
Ano he classical way o assessing he mobili y o ace elemen s is by leaching, whe he on si e o
a he labo a o y. By using es columns o ba ch es s, one can un iso he ms o adso p ion-deso p ion
cu es and model he esul s as a unc ion o pH o he amoun o each con aminan and i s na u e wi h
a iew o p edic ing he beha io o a soil. This me hodology can be used in combina ion wi h one o
he p e ious al e na i es. Fo example, adso p ion-deso p ion iso he ms can be used join ly wi h
specia ion esul s ob ained om sequen ial ex ac ions and me al solubili y modeling condi ions o
p edic he geochemical mechanisms go e ning me al leaching and mobili y in soil. The so wa e
PHREEQC-2 [27] is among he mos widely used o modeling in his con ex .
Al hough all specia ion me hods (ope a ional, unc ional, chemical, chemical-mine alogical, di ec )
and modeling o hei esul s p o ide us wi h a b oad pic u e o he po en ial “a ailabili y” o elemen s
in soil and hei ease o abso p ion by plan s, each ype o plan abso bs elemen s in a speci ic way.
Thus, some elemen s a e mo e eadily abso bed, and some plan s a e mo e selec i e abso be s, han
o he s. Chojnacka e al. [28] de ined he so-called “ ans e coe icien ” o a me al as i s concen a ion
in plan issue in ela ion o soil. This coe icien is maximal o Cd, Tl, Zn, Sn and Cu; in e media e
o Ni; and minimal o Co, C , Pb, As and Sn. As a ule, he mo e pe sis en a gi en ace con aminan
in soil is, he mo e s able i is and he lowe i s bioa ailabili y and oxici y a e.
3. Claim o Soils Con amina ed by T ace Elemen s
Whe eas o claim a soil is con amina ed is pu ely an adminis a i e ac ion, o ac ually demons a e i
is no an easy ask. Wi hin he con ex o his cu en wo k, con amina ion could be de ined as he
p esence o an anomalous high le el o a gi en elemen in he soil. Howe e since no soil in he wo ld
is p is ine and comple ely uncon amina ed, i is qui e di icul o de e mine i i has been con amina ed
o no . In ac , e e y soil has been unde some kind o human p essu e leading o a g ea e o lesse
Mine als 2011, 1
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Figu e 2. Me hodological app oach ollowed in his s udy.
Majo elemen s we e de e mined by induc i ely coupled plasma op ical emission spec ome y
(ICP-OES) and mino elemen s by bo h ICP-OES and ins umen al neu on ac i a ion analysis
(INAA). Chemical specia ion was done in 11 samples o ag icul u al soils, ollowing he scheme
o iginally p oposed by Tessie e al. [17] as subsequen ly modi ied by Galán e al. [21]. The ace
elemen s ex ac ed by each sol en we e de e mined spec opho ome ically. Mine alogical specia ion
was pe o med on 7 samples selec ed in e ms o hei ace me als con en , i on oxides, and
phyllosilica es. Tha was done using XRD o iden i y he mine al phases p esen in he solid esidues
le by he di e en ex ac an s in Tessie ’s p o ocol. Fo subsequen cha ac e iza ion, scanning
elec on mic oscopy (SEM-EDS) and mic opa icle induced X- ay emission (mic oPIXE) spec oscopy
we e also used.
Soil sampling a andom.
G inding, sie ing,
homogenizing
S a is ical ea men
Discussion
CONCLUSIONS
pH Chemical analysis
Majo (ICP-OES)
and ace (ICP-OES,
INAA)
Mine alogical analysis
Global sample
(DRX, Powde
Me hod)
<2µm acción
(AO, EG, 550 °C)
Semiquan i a i e analysis
Chemical
Specia ion
(Tessie )
Bioa ailabili y.
Acid wa e and
EDTA
ex ac ions
Cha ac e iza ion SEM-EDS
and P ó on
Mic obeam
(mic oPIXE)
XRD o solids
esidues al e each
ex ac ion
Mine alogical Specia ion
<2 mm ac ion

Mine als 2011, 1
89
Bioa ailabili y was assessed ex ac ing he samples wi h a 0.05 M solu ion o EDTA in sodium
o m a pH 7 unde con inuous s i ing o 1 h. Acid-ex ac able me als we e ob ained ea ing he
samples wi h wa e acidi ied wi h HNO3 o pH 1 unde con inuous s i ing o 1 h. Bo h ex ac s we e
spec opho ome ically analyzed.
In o de o con i m some ela ionships be ween elemen s wi h a simila geochemical beha iou in
he soils, he esul s we e subjec ed o co ela ion analysis and p incipal componen analysis.
Mo eo e , in o de o acili a e spa ial analysis o he da a and mapping po en ially dange ous zones
o ag icul u al use, each sample was ela ed o i sel and o all o he s by using a Geog aphic
In o ma ion Sys em (GIS). Speci ically, alphanume ic alues we e in oduced as inpu in o a da abase
and geo e e enced o ob ain geog aphic loca ion mapping ou pu s and de elop in e ac i e maps o
display speci ic da a o he sample conce ned. Tha was done using he so wa e A cGIS . 9.2. All
in o ma ion collec ed was eco ded on a e e ence sys em used by he Spanish Geog aphic Ins i u e
(IGN) and Spain’s A my Mapping Se ice (SCE) o zone 30 in he 1950 Eu opean Da um (ED-50),
which was made compulso y in ou coun y by Dec ee 2303/1970.
5.3. Resul s and Discussion
5.3.1. Cha ac e iza ion o Ag icul u al Soils
The soil samples s udied we e ound o con ain high p opo ions o g a el occasionally exceeding
50%. The e o e he soils we e classi ied as sandy g a el. Because o hei sandy na u e, hese soils
ha e a low abili y o abso b ace elemen s. In ac only hose in Ne a zones, which we e sligh ly
mo e clayey, we e able o e ain g ea e amoun s o he elemen s s udied. Soil pH anged om 4.6 o
7.6, he mos acid samples being hose collec ed e y nea he Peña del Hie o mine, Mon e So ome o
and Tha sis (wi h pH < 5.5). These esul s a e simila o hose o con amina ed soils in Mexico [58]
and Mendips, England [86]. pH is a e y impo an pa ame e since he concen a ion o hyd ogen ions
in soil in luences he bioa ailabili y o ace elemen s and nu ien s. Also, i can be unde s ood as a
measu e o soil de iciencies o al e a ion [87,88]. Mos o he me als s udied end o be mo e eadily
a ailable a an acid pH. As a ule, he con en s in di alen me als such as Cu, Zn, Ni, Co, Cd and Mn
dec eased when inc easing he pH [67,89].
The mine als ound in he samples consis ed mainly o qua z, phyllosilica es and eldspa s. The
la e a e calcium plagioclases which explains he high Ca con en s o some samples despi e he
absence o ca bona es. The e we e also subs an ial amoun s o hema i e and goe hi e in some samples
om Tha sis, Rio in o and Las Delgadas. The high con en in i on oxides o some samples
(5–13% Fe2O3)––pa icula ly he ones o m nea he Tha sis and So iel mines, and om some si es in
Rio in o ––whe e no hema i e o goeh i e was de ec ed, sugges he p esence o i on gels. This is an
in e es ing inding since he high speci ic su ace a ea and chemical eac i i y o hese ma e ials play a
majo ole in he so p ion o ace elemen s (pa icula ly me als such as Cu, Pb, and As) [90].
The <2 μm ac ion consis ed o illi e, kaolini e and chlo i e as majo mine als, in addi ion o
smec i e in some samples om zones wi h al e ed olcanic ocks (Be ocal, Ma igen a, Zalamea).
Some lep osols (soils wi h shales as pa en ocks) we e ound o con ain chlo i e- e miculi e mixed
laye s (Peña del Hie o, Rio in o) and illi e-smec i e mixed laye s (Las Delgadas). Unlike o he
Mine als 2011, 1
90
con amina ed soils [79], no ja osi e was de ec ed in any sample since hei pH, abo e 3, p ecluded
i s o ma ion.
The soils we e poo in alkaline and alkaline-ea h me als. Thei con en s in CaO, K2O, MgO and
Na2O ne e exceeding 5%. These esul s a e consis en wi h hose epo ed by Chopin e al. [76]
o Tha sis soils, and hose epo ed by Fe nández Caliani e al. [77], Ba ba e al. [83] and
López e al. [80] o o he simila ly con amina ed soils in he Ibe ian Py i e Bel .
The spa ial dis ibu ion o majo elemen s in soils explains he exis ence o a zone wi h an inc eased
abundance o i on and manganese associa ed o olcanic ocks (Figu e 3), which is iden i ied in he
sou h o he s udy a ea [91].
Figu e 3. Spa ial dis ibu ion o Fe and Mn oxides o samples s udied a Rio in o
Mining Dis ic .
The ace elemen s s udied included As, Cd, Co, Ni, Cu, Pb and Zn, which a e especially abundan
in soils a ec ed by sulphide mining [4]. All o hem can be ound in he US EPA p io i y pollu an lis .
The con en s in As anged om 19 o 994 ppm and peaked in he samples ex ac ed om Tha sis
(994 ppm) and So iel (882 ppm), which clea ly exceeded he a e age alue (227 ppm). This is logical
i we conside hese samples we e unde he di ec in luence o dumps and we e hus mine soils. The
con en s in Pb anged om 40 o 4,900 ppm. The highes alues belong o he samples ex ac ed om
Tha sis (2,650 ppm) and So iel (4,890 ppm). Those o Zn anged om 95 o 900 ppm and hose o Cu
om 27 o 1,160 ppm; he la e , howe e , we e high in mos samples and clea ly exceeded he
egional backg ound le el o his elemen [85]. The Co, C and Ni con en , which we e no oo high,
exceeded hei espec i e egional backg ound le els o Las Delgadas, Ma igen a and Zalamea zones.
The anomalous high le els hey show we e possibly geogenic and associa ed o he pa en ock [84].
Mine als 2011, 1
91
Excep o Cd, all he elemen s exceeded he le els o he 95 pe cen ile in Andalusian soils and he
90 pe cen ile o he geological domain o he Sub-Po uguese Zone [85].
In he ag icul u e soils, which we e no di ec ly unde he in luence o acid mining d ainage, he
ace elemen s con en s exceeded he c i ical eco oxic concen a ion es ablished by Kaba a-Pendias [10],
excep o Cd and Zn (Table 7). Also, he mean alues o all elemen s we e simila o hose p e iously
ound in Tha sis (Ibe ian Py i e Bel ) by Chopin and Alloway [79].
Table 7. Minimum and maximum alues (mean) o some soils close o mining exploi a ions
and e e ence alues. Da a in mg/kg.
Soils a ec ed
by mining
exploi a ion
As Cd Cu Pb Zn C
Sou h
Ko ea [56] 23.3–75.9 (47.7) 2.6–6.1 (4.3) 40–99 (59) 289–948 (477) 275–568 (384) -----
Ko ea [47] 64.8–131 (99.6) ----- 49.6–50.3 (50) 2–11.3 (6.7) 153–322 (237) -----
China [48] ---- 4–24 (8) 11–100 (15) 11–380 (15) 33–1,600 (52) 48
Some se ,
England [86] ----- 0.5–127
(2.1)
2.8–145
(12) 8–1,000 (52) 14–8,344 (132)
Mexico [58] 7–1738 (569) ----- ----- 30–3,450 (312) ----- -----
“La Unión”,
Spain [69] ----- 2–322
(41) 36–2,255 (332) 0–19,000 (8) 1,200–53,100
(12.5)
“San Quin ín”,
Spain [94] ---- (3.76) (57.01) (393) (596) ----
“Tha sis”
Spain [79] 2–1519 (94) ---- 20–3,090 (216) 18–6,350 (172) 45–870 (118) ------
“Rio in o”
Spain [80] 12–204 (68) 0.3–3.2 (0.53) 47–586 (181) 34–605 (177) 72–795 (197) 48–776 (149)
Wo ld no mal
alues [4] 6 0.35 70 30 35 ------
Allowable
alues [10] 20 3 100 100 300 54
The ac o analysis be ween ace elemen s sugges s an associa ion be ween Cu, Pb, Zn and As on
he one hand, and C , Ni, Co and Fe on he o he (Table 8). This is a logical esul because o he
p esence o massi e sul ides––and also, occasionally, eins o hese elemen s––associa ed o he
olcano sedimen a y complex in he Sub-Po uguese Zone [91]. The p incipal componen analysis
con i med hese wo associa ions, which we e ela ed o he po en ial o igin o he elemen s. Thus, C ,
Ni and Co we e essen ially geogenic, whe eas Pb, Zn, As and Cu we e ma kedly an h opogenic. I
should be no ed ha , unlike less con amina ed soils [92-94], none o he ace elemen s we e ela ed o
he phyllosilica e con en ound in he soil es ed.
Mine als 2011, 1
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Table 8. Eigen ec o s F1 and F2 a e a imax o a ion.
Elemen Fac o 1 Fac o 2
Cu 0.840748 −0.09327
Cd 0.647392 −0.12501
Pb 0.916278 0.067878
Ni −0.16902 0.870814
Zn 0.882436 0.078646
As 0.910778 0.081364
Co 0.130555 0.892078
C −0.26457 0.883246
Fe 0.34058 0.843938
SiO2 −0.15414 −0.72585
Phillosilica es −0.35041 0.568918
Expl.Va 3.951898 3.938739
P p.To l 0.359263 0.358067
5.3.2. Chemical Specia ion
O e all, he sum o ace elemen con en s in each sequen ial ex ac ion was compa able o hose in
he o al sample acco ding o he INAA and he ICP-OES (Table 9). Al hough some samples exhibi ed
e y di e en alues, hey would be accep ed i he combined me al con en s o hei di e en
ac ions we e wi hin a ange o ± 10% in ela ion o hose in he o al sample [95,96].
Table 9. Chemical analyses o sequen ial ex ac ions (mg/kg). Samples di ec ly a ec ed by
was e ock piles o acid leacha es a e in bold.
F ac ion Loca ion Sample As Fe Pb Zn Cd Cu Co Ni
To al sample
Peña Hie o RT-4-1 77 37,400 145 186 1 212 24 38
Peña Hie o RT-5-1 54 47,500 66 91 0 97 11 39
Peña Hie o RT-6-1 103 46,900 108 215 1 586 12 40
Las Delgadas RT-8-1 18 10,900 39 127 0 80 88 424
Las Delgadas RT-8-2 120 51,500 126 114 0 245 12 43
Ne a RT-20-1 77 51,800 598 795 3 495 15 47
Ne a RT-21-1 204 52,300 563 374 3 482 18 38
Ne a RT-21-2 197 48,400 603 388 1 526 16 41
Tha sis R -28 444 65,600 1,270 667 1 198 41 51
Tha sis R -29 994 88,100 2,650 897 1 443 70 54
So iel R -30 882 70,900 4,890 585 1 1160 19 48
In e changeable
Peña Hie o RT-4-1 2 0 2 109 0 6 0 1
Peña Hie o RT-5-1 1 1 5 9 0 4 0 0
Peña Hie o RT-6-1 1 0 1 0 0 20 0 0
Las Delgadas RT-8-1 1 0 1 0 0 2 0 5
Las Delgadas RT-8-2 1 0 14 20 0 9 0 0
Ne a RT-20-1 1 0 1 22 0 4 0 0
Ne a RT-21-1 1 0 1 14 0 8 0 0
Ne a RT-21-2 1 0 1 11 0 7 0 0
Tha sis R -28 5 0 35 211 1 0 N.D. 7
Tha sis R -29 8 0 114 337 1 10 N.D. 18
So iel R -30 20 0 83 15 1 33 N.D. 0
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93
Table 9. Con .
F ac ion Loca ion Sample As Fe Pb Zn Cd Cu Co Ni
Labil/ca bona es
Peña Hie o RT-4-1 2 180 10 336 0 132 4 1
Peña Hie o RT-5-1 2 126 25 0 0 43 0 1
Peña Hie o RT-6-1 2 39 41 659 0 390 9 8
Las Delgadas RT-8-1 2 248 2 0 0 9 6 47
Las Delgadas RT-8-2 2 89 49 24 0 191 1 3
Ne a RT-20-1 2 28 94 1713 2 268 2 4
Ne a RT-21-1 2 27 48 428 0 96 2 1
Ne a RT-21-2 2 25 54 404 0 98 0 1
Tha sis R -28 20 180 162 26 1 17 N.D. 2
Tha sis R -29 26 2,747 457 202 1 92 N.D. 7
So iel R -30 42 1,371 1,574 342 1 455 N.D. 7
Fe-Mn Oxides
Peña Hie o RT-4-1 1 15,174 22 24 2 72 5 2
Peña Hie o RT-5-1 1 20,484 11 8 3 36 1 2
Peña Hie o RT-6-1 1 24,779 19 32 4 276 2 3
Las Delgadas RT-8-1 1 30,348 9 9 5 26 17 39
Las Delgadas RT-8-2 1 20,861 18 7 3 68 1 2
Ne a RT-20-1 1 15,322 60 118 3 177 2 4
Ne a RT-21-1 1 14,106 70 58 2 174 3 2
Ne a RT-21-2 1 14,261 62 50 2 167 2 2
Tha sis R -28 194 47,984 1,259 3,414 0 214 N.D. 31
Tha sis R -29 513 70,834 2,781 5,713 1 390 N.D. 30
So iel R -30 246 42,384 3,877 2,740 1 1,380 N.D. 23
O ganic ma e
Peña Hie o RT-4-1 1 1,789 1 13 0 3 1 2
Peña Hie o RT-5-1 1 1,774 1 7 1 1 7 3
Peña Hie o RT-6-1 1 1,384 1 6 0 5 0 2
Las Delgadas RT-8-1 1 2,803 1 5 1 1 3 16
Las Delgadas RT-8-2 1 1,137 1 4 0 2 0 2
Ne a RT-20-1 1 1,306 2 14 0 13 0 2
Ne a RT-21-1 1 1,730 3 9 0 6 0 2
Ne a RT-21-2 1 1,487 3 7 0 4 0 2
Tha sis R -28 15 2,892 99 79 0 57 N.D. 6
Tha sis R -29 39 2,947 158 66 0 126 N.D. 4
So iel R -30 24 2,861 292 180 0 17 N.D. 5
Residue
Peña Hie o RT-4-1 71 20,257 110 0 0 0 14 32
Peña Hie o RT-5-1 50 25,114 25 67 0 12 2 33
Peña Hie o RT-6-1 99 20,698 47 0 0 0 1 27
Las Delgadas RT-8-1 13 75,601 26 113 0 43 62 317
Las Delgadas RT-8-2 116 29,413 44 59 0 0 9 36
Ne a RT-20-1 73 35,144 441 0 0 32 11 36
Ne a RT-21-1 200 36,437 442 0 0 198 12 33
Ne a RT-21-2 193 32,627 486 0 0 249 13 36
Tha sis R -28 98 28,157 1,210 861 0 24 N.D. 14
Tha sis R -29 366 14,135 644 961 0 61 N.D. 17
So iel R -30 245 17,395 1,291 112 0 110 N.D. 13
N.D.: no de ec ed.

Mine als 2011, 1
94
I should be no ed ha only Cd was p esen in high p opo ions in he exchangeable ac ion.
Howe e i s p esence was no haza dous because o hei low o al con en . All o he ace elemen s
we e la gely associa ed o i on oxyhyd oxides and he esidual ac ion. These esul s con i m he
p esence o amo phous oxyhyd oxides capable o inco po a ing la ge amoun s o me al ca ions [24].
Figu e 4. Sequen ial ex ac ion o se e al ace elemen s in selec ed samples. Samples
di ec ly a ec ed by mining was es o leacha es a e highligh ed.
A senic and Ni we e associa ed o he i on and manganese oxides ac ion in he samples di ec ly
a ec ed by mining was es and o he esidual ac ion in all o he s. Hence i was sca cely p esen in he
mos mobile ac ions (Figu e 4). Coppe was p esen in all ac ions, bu la gely associa ed o labile
ac ions and i on and manganese oxides i ually in all samples. Lead and zinc we e associa ed o i on
and manganese oxides and in he insoluble esidue, bu also o labile ac ions. The ac ha Zn, Pb and
Cu we e pa ially associa ed o he exchangeable ac ion ha consis ed o phyllosilica es and
ca bona es, sugges s ha hei p esence was a esul o ion exchange in clay mine als o p ecipi a ion
as oxides on hei su ace.
As
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Fe
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Pb
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Zn
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Cu
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Ni
0%
20%
40%
60%
80%
100%
RT-4
RT-5
RT-6
RT-8
RT-20
RT-21
R -28
R -29
R -30
Samples
Ex ac ed %
F1
F2
F3
F4
F5
Mine als 2011, 1
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Simila esul s we e p e iously epo ed o soils unde he in luence o mining was e in China and
Ko ea [52,97], and he Pb-Zn mine in San Quin ín (Spain) [94]. In conclusion, mos o he elemen s
s udied we e adso bed in (o as s uc u al componen o ) i on oxyhyd oxides, o p esen in he esidual
ac ion. The e o e, he p esen physical–chemical condi ions o he soils acili a e he immobiliza ion
o he oxic elemen s s udied, bu hei cu en le els pose a po en ial haza d ha wa an s assessmen .
5.3.3. A ailabili y and Bioa ailabili y Tes s
The ac ion ex ac ed wi h acid wa e con ained all elemen s s udied, some a i ually negligible
concen a ions and o he s, including Fe, Mn, Zn, Cu and Pb, a e y high le els (close o he 40% in
some samples). As i can be no iced in Figu e 5, As and Ni exhibi ed a high a ailabili y in all samples
unde he di ec in luence o a mine dump, maybe because bo h elemen s we e associa ed o i on oxides.
Figu e 5. Acid wa e and EDTA ex ac ions in selec ed samples wi hou esul s o Fe, Mn,
Pb, Zn and Cu. Samples di ec ly a ec ed by mining was es o leacha es a e highligh ed.
The ac ion ex ac ed wi h EDTA also con ained all elemen s. As Figu e 5 shows, As was highly
a ailable, especially in soils nea he mines in Tha sis (R 28-29) and So iel (R -30), which con ained
EDTA
0
20
40
60
80
100
RT-4-1
RT-5-1
RT-6-1
RT-8-1
RT-8-2
RT-20-1
RT-21-1
RT-21-2
R -28
R -29
R -30
Samples
Concen a ion (mg/kg)
Ni
Co
Cd
As
Acid Wa e
0
20
40
60
80
100
RT-4-1
RT-5-1
RT-6-1
RT-8-1
RT-8-2
RT-20-1
RT-21-1
RT-21-2
R -28
R -29
R -30
Samples
Concen a ion (mg/kg)
Ni
Co
Cd
As
Mine als 2011, 1
96
high le els o ace elemen s. Simila esul s we e p e iously ob ained in ag icul u al soils and ice
ields in Ko ea, whe e As, Cu and Zn we e highly bioa ailable and posed se ious heal h haza ds [47].
5.3.4. Mine alogical Specia ion
The XRD esul s ob ained om he di e en ac ions did no allow us o assign he di e en ace
elemen s o speci ic mine al phases because he ac ions we e e y simila in mine alogical e ms, and
he de ec ion o mino mine al phases was no possible wi h his me hod.
The SEM s udy con i med he p esence o he majo mine als de ec ed by XRD (qua z,
phyllosilica es, eldspa s and i on oxides) in addi ion o accesso y mine als such as py i e, ba i e,
zi con, u ile, monazi e and ilmeni e (Table 10). No associa ion o any ace elemen o clay mine als
was de ec ed hough. Mic og aphs e ealed he p esence o i on oxide agg ega es con aining
subs an ial concen a ions o Pb and smalle amoun s o As and Sb (Figu e 6). The e we e also isola ed
py i e c ys als ans o med in o i on oxides (hema i e) associa ed o no ace elemen . Some samples
addi ionally con ained galena.
Table 10. Mine alogical composi ion o o al and <2 µm ac ion by XRD and SEM-EDS.
Samples di ec ly a ec ed by was e ock piles o acid leacha es a e in bold
Loca ion Sample Q Phy Fd Hem V K Ch I O he s
Peña
Hie o RT-4–1 55 34 6 - T 15 - 83 Ilmeni e, zi con, ba i e, u ile, monazi e
and ce iani e
Peña
Hie o RT-5–1 45 44 6 - 5 35 - 60 Ilmeni e, zi con, u ile and monazi e
Peña
Hie o RT-6–1 57 38 T - 5 5 - 90 Ru ile, monazi e and ilmeni e
Delgadas RT-8–1 7 61 27 T Non quan i iable Py i e
Delgadas RT-8–2 52 43 T X Monazi e, ba i e and u ile
Ne a RT-20–1 55 40 T X 5 - 5 90 Ba i e, monazi e, u ile, ilmeni e
Ne a RT-21–1 53 35 7 - 5 - 5 90 Zi con, ba i e, u ile, monazi e
Ne a RT-21–2 59 31 5 - 5 - 5 90 Pb an imonide, cassi e i e, py i e, Pb
associa ed o sulphides.
Tha sis R -28 56 34 5 T - 21 - 79 Fe oxy-hyd oxides wi h Pb
Tha sis R -29 76 24 5 - - 30 - 70 Fe oxy-hyd oxides wi h Pb
So iel R -30 80 16 4 - - 15 - 85 Fe oxy-hyd oxides wi h Pb
Q: qua z; Phy: Phyllosilica es; Fd: Feldspa ; Hem: Hema i e; V: Ve miculi e: K: Kaolini e;
Chl: Chlo i e; I: Illi a; T : <5%.
Mine als 2011, 1
97
Figu e 6. SEM image showing a polyc ys alline agg ega e composed o i on oxides,
micas, qua z and apa i e. The spec um show Pb, Sb and As peaks.
Figu e 7. Composi ional mapping o majo and ace elemen s by means o mic oPIXE
(sample 21).
Selec ed samples we e subjec ed o a mic op o on p obe (PIXE) s udy in hei <63 μm ac ion. The
esul s we e used o p oduce dis ibu ion maps o majo and ace elemen s. Some o hese elemen s
such as Al, we e uni o mly dis ibu ed ac oss he s udy a ea (Figu e 7), whe eas o he s
(Si, Mn, As, Cu, Pb and Zn) appea ed accumula ed in small g anules. The esul s we e exp essed in
quan i a i e o m using he da a acquisi ion so wa e OMDAQ o ans o m he s udy a ea in o a
ma ix o 256 × 256 elemen s con aining a PIXE spec um each. Tha p o ided he o e all PIXE
spec um o he a ea and he indi idual spec a o each zone o po en ial in e es . This allowed us o
Mine als 2011, 1
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34. Sie a, M.; Díez, M.; Ma inez, J.; Fe nández, J.; Aguila , J. A new index o e alua e he
anomalies o ace elemen s in soils. The case o SE Spain. Span. J. Ag ic. Res. 2009, 7, 933-943.
35. Finnecy, K.; Pea ce, I. Land Con amina ion and Reclama ion. In Unde s anding o Ou
En i onmen ; Hes e , R.E., Ed.; Royal Soc. o Chemis y: London, UK, 1986; pp. 329-337.
36. Kloke, A.; Einkmann, T. Nu zung- und schu zbezogene O ien ie ungsda en ü (Schad) S o e in
Böden, Sonde d uck aus He 1.8.; E ich Schmid Ve lag: Be lin, Ge many, 1991.
37. Salminen, R.; Ta ainen, T. The p oblem o de ining geochemical baselines. A case s udy o
selec ed elemen s and geological ma e ials in Finland. J. Geochem. Explo . 1997, 60, 91-98.
38. Baize, D.; S e ckeman, T. O he necessi y o knowledge o he na u al pedo-geochemical
backg ound con en in he e alua ion o he con amina ion o soils by ace elemen s. Sci. To al
En i on. 2001, 264, 127-139.
39. Ta ainen, T.; Kallio, E. Baselines o ce ain bioa ailable and o al hea y me al concen a ions in
Finland. Appl. Geochem. 2002, 17, 975-980.
40. Salomons, W. En i onmen al impac o me als de i ed om mining ac i i ies. J. Geochem. Explo .
1995, 53, 53-56.
41. Me e ield, J.R. Sedimen Mine alogy and he En i omen al Impac o Mining. In Sedimen and
Wa e Quali y in Ri e Ca chmen s; Fos e , I.D.L., Gu nell, A.M., Webb, B.W., Eds.; Wiley:
Hoboken, NJ, USA, 1995; pp.145-160.
42. Macías, F. Con aminación de Suelos: Algunos Hechos y Pe spec i as. In P oblemá ica
Geoambien al y Desa ollo; O iz Silla, R., Ed.; V Reunión Nacional de Geología. Ambien al y
O denación del: Te i o io, Spain, 1993; olume I, pp. 53-74.
43. Macías, F. Los Suelos de Mina: Su Recupe ación. In E aluación y Manejo de Suelos; Aguila , J.,
Ma ínez, A., Roca, A., Eds.; Uni e sidad de G anada: G anada, Spain, 1996; pp. 227-243.
44. Reimann, C.; Kolle , F.; Kashulina, G.; Niska aa a, H.; Englmaie , P. In luencie o ex eme
pollu ion on he ino ganic chemical composi ion o some plan s. En i on. Pollu . 2001, 115,
239-252.
45. G a on, W.S.; Nkongolo, K.K.; Spie s, G.A. Hea y me al accumula ion in soil and Jack pine
(Pinus banksiana) needles in Sudbu y, On a io, Canada. Bull. En i on. Con am. Toxicol. 2000,
64, 550-557.
46. Robinson, B.; Mills, T.M.; Pe i , D.; Fung, L.E.; G een, F.S.; Clo hie , B.E. Na u al and induced
cadmium accumula ion in popla and willows; Implica ions o phy o emedia ion. Plan Soils
2001, 227, 301-306.
47. Lee, S.; Lee, B.; Kim, J.; Kim, J.; Lee, J. Human isk assessmen o hea y me als and as
con amina ion in he abandoned me al mine A eas, Ko ea. En i on. Moni . Assess. 2006, 119,
233-244.
48. Zabowski, D.; Hen y, C.L.; Zheng, Z; Zhang, X. Mining impac s on ace me al con en o wa e ,
soil and s eam sedimen s in he Hei Ri e Basin, China. Wa e Ai Soil Pollu . 2001, 131,
261-273.
49. Lin, C.; Tong, X.; Lu, W.; Yan, L.; Wu, Y.; Nie, C.; Chu, C.; Long, J. En i onmen al impac s o
su ace mining on mined lands, a ec ed s eams and ag icul u al lands in he Dabaoshan mine
egion, sou he n China. Land Deg ad. De . 2005, 16, 463-474.

Mine als 2011, 1
105
50. Lee, C. Assessmen o con amina ion load on wa e , soil and sedimen a ec ed by he Kongjujeil
mine d ainage, Republic o Ko ea. En i on. Geol. 2003, 44, 501-515.
51. Sun, Y.; Xie, Z.; Li, J.; Xu, J.; Chen, Z.; Naidu, R. Assessmen o oxici y o hea y me al
con amina ed soils by he oxici y cha ac e is ic leaching p ocedu e. En i on. Geochem. Heal h
2006, 28, 73-78.
52. Zhou. J.; Dang, Z.; Cai, M.F.; Liu, C. Soil hea y me al pollu ion a ound he dabaoshan mine,
Guangdong P o ince, China. Pedosphe e 2007, 17, 588-594.
53. Chae, Jung, M. Hea y me als concen a ions and ac o a ec ing me al up ake by plan s in he
icini y o a Ko ea Cu-W mine. Senso s 2008, 8, 2413-2423.
54. Chae Jung, M. Con amina ion by Cd, Cu, Pb, and Zn in mine was es om abandoned me al
mines classi ied as mine aliza ion ypes in Ko ea. En i on. Geochem. Heal h 2008, 30, 205-217.
55. Chae Jung, M. Hea y me al con amina ion o soils and wa e s in and a ound he Imcheon Au-Ag
mine, Ko ea. Appl. Geochem. 2001, 16, 1369-137.
56. Kim, J.; Kim, K.; Lee, J.; Lee, J.; Jenny Cook, J. Assessmen o as and hea y me al
con amina ion in he icini y o Duckum Au-Ag mine, Ko ea. En i on. Geochem. Heal h 2002,
24, 213-225.
57. Noble, R.; Hough, R.M; Wa kins, R.T. En ichmen and exposu e assessmen o As, C and Pb o
he soils in he icini y o S awell, Vic o ia, Aus alia. En i on. Geochem. Heal h 2010, 32,
193-205.
58. Razo, I.; Ca izales, L.; Cas o, J.; Díaz-Ba iga, F.; Mon oy, M. A senic and hea y me al
pollu ion o soil, wa e and sedimen s in a semi-a id clima e mining a ea in Mexico. Wa e Ai
Soil Pollu . 2004, 152, 129-152.
59. Gu ie ez Ruiz, M. Suelos y sedimen os a ec ados po la dispe sión de jales inac i os de sul u os
me álicos en la zona mine a de San a Bá ba a, Chihuahua, México. Re . Mex. Cienc. Geol. 2007,
24, 170-184.
60. Veado, M.A.; A an es, I.A.; Oli ei a, A.H.; Almeida, M.R.; Miguel, M.I.; Se e o, M.I.;
Cabalei o, H.L. Me al pollu ion in he en i onmen o minas ge ais s a e––B azil. En i on.
Moni . Assess. 2007, 117, 157-172.
61. He be , R.B. Pa i ioning o hea y me als in podzol soils con amina ed by mine d ainage wa e s,
Dala na, Sweden. Wa e Ai Soil Pollu . 1997, 96, 39-59.
62. Da ies, E.; Bailinge , R. Hea y me als in soils in no h Some se , England, wi h special
e e ence o con amina ion om base me al mining in he Mendips. En i on. Geochem. Heal h
1990, 12, 291-300.
63. Dudka, S.; Pio owska, M.; Chlopecka, A.; Wi ek, T. T ace me al con amina ion o soils and
c op plan s by he mining and smel ing indus y in Uppe Silesia, Sou h Poland. J. Geochem.
Explo . 1995, 52, 237-250.
64. Aleksande -Kwa e czak, U.; Helios-Rybicka, E. Con amina ed sedimen s as a po en ial sou ce o
Zn, Pb, and Cd o a i e sys em in he his o ical me alli e ous o e mining and smel ing indus y
a ea o Sou h Poland. J. Soils Sedimen s 2009, 9, 13-22.
65. Ho mann, T.; Schuwi h, N. Zn and Pb elease o sphale i e (ZnS)-bea ing mine was e ailings.
J. Soils Sedimen s 2008, 8, 433-441.
Mine als 2011, 1
106
66. Gazdag, E.R.; Sip e , E. Geochemical backg ound in hea y me als and human heal h isk
assessmen a an o e mine si e, Gyongyoso oszi (No h Hunga y). Ca pa hian J. Ea h En i on.
Sci. 2008, 3, 83-92.
67. Ab eu, M.M.; Ma ias, M.J.; Cla a, M.; Magalhães, F.; Bas o, M.J. Impac s on wa e , soil and
plan s om he abandoned Miguel Vacas coppe mine, Po ugal. J. Geochem. Explo . 2008, 96,
161-170.
68. Ta a es, M.J.; Sousa, J.; Ab eu, M.M. O dina y k iging and indica o k iging in he ca og aphy
o ace elemen s con amina ion in São Domingos mining si e (Alen ejo, Po ugal). J. Geochem.
Explo . 2008, 98, 43-56.
69. Na a o, M.C.; Pé ez-Si en , C.; Ma ínez-Sánchez, M.J.; Vidal, J.; To a , P.J.; Bech, J.
Abandoned mine si es as a sou ce o con amina ion by hea y me als: A case s udy in a semi-a id
zone. J. Geochem. Explo . 2008, 96, 183-193.
70. Ga cía Lo enzo, M.L. E aluación de la con aminación po ía híd íca de elemen os aza en
á eas con in luencia mine o-me alú gicas. Aplicación a la Sie a Mine a de Ca agena-La
Unión (Mu cia). Memo ia Tesis Doc o al, Uni e sidad de Mu cia: Mu cia, Spain, 2009.
71. Ma ínez-Sánchez, M.J.; Ga cía-Lo enzo, M.L.; Molina-Ruiz, J.; Pé ez-Si en . M.C. Mapping
o ace elemen s con amina ion in an abandoned mining si e in a semia id zone. J. Geochem.
Explo . 2011, 109, 1-7.
72. Molina, J.; Oya zun, R.; Esb í, J.M.; Higue as, P. Me cu y accumula ion in soils and plan s in he
Almadén mining dis ic , Spain: One o he mos con amina ed si es on Ea h. En i on. Geochem.
Heal h 2006, 28, 487-498.
73. Collado Fe nández, D.; Sánchez Ga ido, J.; Na a o Flo es, A.; del Mo al To es, F. Suelos
desa ollados sob e ma e iales alu iales a ec ados po ac i idades mine as en la zona de El
Há ela (Cue as de Almanzo a, Alme ia). Eda ología 2000, 7, 217-225.
74. Ma ínez, J. Ca ac e ización Geoquímica y Ambien al de Los Suelos del Sec o Mine o de
Linaes; Tesis doc o al de la Uni e sidad Poli ecnica de Mad id: Mad id, Spain, 2002.
75. Adelino, M.A.; Rome o, A.; González, I. Geochemical Anomalies in Soils o he Jaen P o ince
(Andalusia, Spain). In Science and Technology o En i onmen al P o ec ion; SETAC:
Pensacola, FL, USA, 2010; p. 214.
76. Chopin, E.; Black, S.; Hodson, M.E.; Coleman, M.L.; Alloway, B.J. A p elimina y in es iga ion
in o mining and smel ing impac s on ace elemen concen a ions in he soils and ege a ion
a ound Tha sis, SW Spain. Mine al. Mag. 2003, 67, 279-288.
77. Fe nández-Caliani, J.C; González, I.; Apa icio, P.; Ba ba, C.; Galán, E. Ni eles de concen ación
de a sénico y me ales pesados en los suelos del en o no de las minas abandonadas de la Faja
Pi í ica Ibé ica. Macla 2005, 3, 73-74.
78. López, M. Es udio de la Con aminación po Me ales Pesados en Suelos Ag ícolas de la
Coma ca Mine a de Rio in o; T abajo de in es igación, pa a la ob ención del Diploma de
Es udios A anzados, Uni e sidad de Se illa: Se illa, Spain, 2006.
79. Chopin, E.I.B.; Alloway, B.J. T ace elemen pa i ioning and soil pa icle cha ac e isa ion a ound
mining and smel ing a eas a Tha sis, Río in o and Huel a, SW Spain. Sci. To al En i on. 2007,
373, 488-500.
Mine als 2011, 1
107
80. López, M.; González, I.; Rome o, A. T ace Elemen s con amina ion o ag icul u al soils a ec ed
by sulphide exploi a ion (Ibe ian Py i e Bel , SW Spain). En i on. Geol. 2008, 54, 805-818.
81. Ba ba, C. Especiación Química y Mine alógica de Elemen os T aza de O igen Mine o en Suelos
Ag ícolas; T abajo ealizado pa a la ob ención del Diploma de Es udios a anzados, Uni e sidad
de Huel a: Huel a, Spain, 2007.
82. Ba ba B ioso, C.; Sánchez Blanco, E.; Fe nández Caliani, J.C. E ec os del D enaje Ácido de
Minas Sob e la Composición Química y Mine alógica de Suelos Ag ícolas. Una Ap oximación
expe imen al. In II Cong eso Ibé ico de la Ciencia del Suelo; Bellin an e, N., Pa ales, I.A.,
Jo dán, A., Ma ínez-Za ala, L., Eds.; IICICS2006: Huel a, Spain, 2007; p. 61.
83. González, I.; López, M.; Rome o, A.; Galán, E. Conside aciones químico-mine alógicas sob e la
mo ilidad de elemen os óxicos en suelos a ec ados po explo aciones mine as de sul u os (Faja
Pi í ica Ibé ica). In Lib o de Resúmenes Reunión SEA; SEA: Se illa, Spain, 2007; pp. 22-24.
84. González, I.; López, M.; Rome o, A., Galán, E., Fe nández Caliani, J.C.; Apa icio, P.
Conside aciones mine alógicas sob e la mo ilidad de elemen os óxicos en suelos ag ícolas
a ec ados po explo aciones mine as de sul u os (Faja Pi í ica Ibé ica). Geo emas 2008, 25, 72-78.
85. Galán, E.; Fe nández Caliani, J.C.; González, I.; Apa icio, P.; Rome o, A. In luence o
geological se ing on geochemical baselines o ace elemen s in soils. Applica ion o soils o
Sou h-Wes Spain. J. Geochem. Explo . 2008, 98, 89-106.
86. Da ies, B.E.; Ballinge , R.C. Hea y me als in soils in no h Some se , England, wi h special
e e ence o con amina ion om base me al mining in he Mendips. En i on. Geochem. Heal h
1990, 12, 291-300.
87. Wen, X.; Allen, H.E. Mobiliza ion o hea y me als om Le An Ri e Sedimen . Sci. To al
En i on. 1999, 227, 101-108.
88. Galán, E. Mine alogía Aplicada; Sín esis, S.A: Mad id, Spain, 2003.
89. Cama, J.; Ayo a; C.; Que ol, X.; Mo eno, N. Me al adso p ion on cáliz om py i e con amina ed
soil. J. En i on. Eng. 2005, 131, 1052-1056.
90. Galán, E.; Gómez A iza, J.L.; González, I.; Fe nández Caliani, .J.C.; Mo ales, E.; Gi aldez, I.
Hea y me als pa i ioning in i e sedimen s se e ely pollu ed by acid mine d ainage in he
Ibe ian Py i e Bel . Appl. Geochem. 2003, 18, 409-421.
91. To nos, F. La geología y me alogenía de la aja pi í ica ibé ica. Macla 2008, 10, 13-24.
92. Papadopaulos, A.; P ochaska, F.; Papadopoulos, F.; Gan idis, N.; Me axa, E. De e mina ion and
e alua ion o cadmium, coppe , nickel and zinc in ag icul u al soils o wes e n Macedonia,
G eece. En i on. Manag. 2007, 40, 719-726.
93. Bech, J.; Tume, P.; Longan, L.; Re e e , F.; Bech, J.; Tume, L.; Tempio, M. Concen a ion o Cd,
Cu, Pb, Zn, Al, and Fe in soils Man esa, NE Spain. En i on. Moni . Assess. 2008, 145, 256-266.
94. Rod íguez, L.; Ruiz, L.; Alonso-Azcá a e, J.; Rincón, J. Hea y me al dis ibu ion and chemical
specia ion in ailings and soils a ound a Pb-Zn mine in Spain. J. En i on. Manag. 2008, 90,
1106-1116.
95. Picke ing, W.F. Me al ion specia ion—Soils and sedimen . O e Geol. Re . 1986, 1, 83-146.
96. Yan, X.P.; Ke ich, R.; Hend y, M.J. Sequencial leacha es o mul iple g ain size ac ions om a
clay- ich ill, Saka chewan, Canada: Implica ions o con ols on he a e ea h elemen
gepchemis y o po ewa e s in an aqui a d. Chem. Geol. 1999, 158, 53-79.
Mine als 2011, 1
108
97. Lee, S. Geochemis y and pa i ioning o ace me als in paddy soils a ec ed by me al mine
ailings in Ko ea. Geode ma 2006, 135, 26-37.
98. Vodyani skii, N. A senic, lead, and zinc compounds in con amina ed soils acco ding o EXAFS
spec oscopic da a: A e iew. Eu asian Soil Sci. 2006, 39, 611-621.
99. Maskall, J.E.; Tho n on, I. Chemical pa i ioning o hea y me als in soils, clays and ocks as
his o ical lead smel ing si es. Wa e Ai Soil Pollu . 1998, 108, 391-409.
100. Song, Y.; Wilson, M.J.; Moon, H.S.; Bacon, J.R.; Bain, D.C. Chemical and mine alogical o ms
o lead, zinc and cadmium in pa icle size ac ions some was es, sedimen s and soils in Ko ea.
Appl. Geochem. 1999, 14, 621-633.
101. O iz, M. Ap oximación a la Mine ía y Me alu gia de Minas de Rio in o Desde la An igüedad
Has a el Siglo XX; Tesis doc o al. Uni e sidad Poli écnica de Mad id: Mad id, Spain, 2003.
102. Legaz, F.; Se na, M.D.; Fe e , P.; Cebolla, V.; P imo-Milla, E. Análisis de Hojas, Suelos y
Aguas Pa a Diagnós ico Nu icional de Plan aciones de Cí icos. P ocedimien o de Toma de
Mues as. Gene ali a Valenciana; Conselle ia d´Ag icul u a, Pesca i Alimen ació: Gene ali a
Valenciana, Spain, 1995.
103. Puga, S.; Sosa, M.; de la Mo a, A.; Pinedo, C.; Jiménez, J. Concen aciones de As y Zn en
ege ación na i a ce cana a una p esa de Jales. Re . In . Con m. Ambien 2006, 22, 75-82.
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