The quantitative distribution o f As, Cu, Pb, Zn elements in vvater and soils around Giáp Lai and Minh Quang suỉfur deposits is presented in this work. The preliminary results delin[r]
Trang 1V N U ]ournal of Sciencc, Earth Sciences 25 (2009) 91-97
D istribution o f A rsenic, C opper, Lead, Z inc elem ents in
w ater and soils o f sulfur deposits
in the N orth W est o f H anoi
D ang Mai*, N guyen Van Vuong, N guyen T rong Ngu
C ollege o f Science, VNU
Reccivcd 02 January 2009; received in revised form 3 February 2009
A bstract The quantitative distribution o f As, Cu, Pb, Zn elements in vvater and soils around Giáp
Lai and Minh Quang suỉfur deposits is presented in this work The preliminary results delineate the
íollovving: i) The content o f As in water is quite lovv and is below the polluted limit The soils vvas
symptomatic o f pollution by As at lovv ỉevel ii) The contents o f Cu and Zn arc higher than that o f
Pb, especially in some localities, Cu and Zn contents are over the permissible threshold o f the
surface water quality and form high anomaỉies iii) The content o f As, Cu, Zn, Pb in the Red
River’s water is higher than that in the expỉoitation area This reveals that the arsenic and other
heavy metals presented in the Red River’s water may come from other sources ỉocated in the upper
course o f the river
Key^vords: Arsenic, Copper, Zinc, Lead; Soiỉs;
1 In tr o d u c tio n
C u rren tly , its ex ists d iíĩe re n t o p inio ns on
th e cau ses o f h eav y m e tallic pollution
(esp ecially a rsen ic ) in th e vvater o f th e B ac Bo
đ e lta plain S om e a u th o rs te n ta tiv e ly co nclude
that the arsen ic, m an g an and am m onium
pollution o f th e u n d erg ro u n d vvater is caused by
ho usehold, in d u strial an d ag ricultural vvaste and
w ater o v e re x p lo ita tio n [3,7] S om e others
em p h asized th e n atu ra l cau ses o f th e pollution
A cco rd in g to N g u y ễn V ăn Đ ản an d N g u y ễn T hị
D ung, c o m p o n e n ts o f th e Q u atern a ry sedim en ts
in th e stu d y area m ay be th e so urce produced
co n tam in ated e le m e n ts [5] Phạm H ù ng V iệt et
Corrcsponding author Tcỉ.: 84-1-38544632
ìr Deposits; Pollution; Hanoi area
%
al arg u e th a t th e e x iste n c e o f high c o n te n t o f
A rsen ic in u n d erg ro u n d w ater o f th e B ac Bo
d e lta plain m a y b e related to th e “e ro sio n and
w eath e rin g p ro c e sse s lead in g to the e n ric h m e n t
o f arsen ic in iron o re s such as iron oxy-
hy drox id e T h e s e o re s w ould b eco m e th e sed im en tary m a teria ls fo r th e fo rm atio n s
b earin g A s" [6]
In th e p re se n t w o rk, One h y p o th e sis h as been íò rm u la te d as follow ing: th e h eav y
m etallic p o llu tio n in th e w a te r o f th e B ac B o delta p lain m ay be c a u se d from su lfu r ores
d ep o sits from th e Red R iver upper co u rse T his
hy p o th esis is rational i f it co n sid ers the
em issio n o f A s and o th er heavy m e tallic elem en ts to th e soil and vvater en v iro n m en t d u e
to su lfu r d isin teg ratio n [1 ,2 ] In o rd er to accept
Trang 292 D M ai et aỉ / V N U Ịoum aỉ o f Science, Earth Sciences 25 (2009) 91-97
o r reje ct th is h yp othesis, G iá p Lai an d M inh
Q u a n g p y rite o res d ep o sits w e re investigated to
c h a ra c te riz e th e g eo chem ical d istrib u tio n s o f
A s, C u , Zn, Pb in so ils an d vvater env iron m ent
s u rro u n d in g th e se deposits
2 M e th o d s
T o stu d y th e d istrib u tio n o f th o se elem en ts
in soil an d vvater en v iro n m en ts in relatio n to the
p y rite ex p lo itatio n and P rocessin g a t th e G iáp
Lai and M inh Q u an g dep o sits, th e su rvey s start
from th e c e n te r o f d ep o sits to b ig g er rivers in
th e area th ro u g h o u t th e sm all stream s In the
M inh Q u an g d eposits, th e su rv ey w as taken
from M inh Q u a n g stream to D a river In the
G iap Lai area , th e survey vvas ta k en from the Bứa riv er to T ứ K ỳ B ridg e, vvhere it co n íluence
w ith the R ed R iver, an d then exp an d ed upvvard and dovvnvvard alo n g th e Red R iver to the Phong C h âu B ridge (F ig 1) T h e investigated targ ets co m p o se o f stream and riv er vvater, household w ell, soils an d ores T h ese sam ples vvere a n aly zed by A to m ic A b so rp tio n m cthod at
S u b -In stitu te o f T ec h n o lo g y an d E n vironm ent
P rotectio n T h e p o lish ed sam p les are exam ined
un d er th e re íle c te d light m icro sco p e A xioscope
40 in the M in eral-P etro lo g ical L ab at H anoi
U niv ersity o f Science
L i s t r u c t ỉ o n s
Ị B o u r x d a i ^ o f ỊXOVÌDCC
# I Sưrvcyed places
à I Pyrirc depDsirs
oo
o
Fig 1 The map shovving the surveyed data
Trang 3D M ai et al. / V N U Ịournaỉ o f Sàence, Earth Sciences 25 (2009) 91-97 93
3 G e n e r a l g e o c h e m ic a l-m in e ra lo g ic a l
c h a r a c te r is tic s o f p y r ite m in c s
3.1 The G iáp L ai p y r ite m ine
I t locates at G iáp Lai co m m u nc, T h an h Sơn
d is tric t, Phú T h ọ p rovince
C o -o rd in ate:
2 101 1'45" N;
105°15'30" E
T h e m ine o rig in ates from h yd rotherm al
m c taso m ato se d type T h e co u n try ro cks include
d o lo m ite m arble, m ica sch ist o f th e Thach
K ho an íò rm atio n , am o n g w hich the m arble
c o n tain s o re m inerals T h ere are app ro x im ately
40 o re bo dies m a k in g parallel array and
c o in cid in g w ith th e azim u th o f co u n try rocks
T h e y have d ifferent sh ap es in clu din g lode,
ía scicu la te and lenticle ty p cs [9] S om e ore
b o d ie s are ex po sed to th e su rface and th e others
still locate u n d er th e su rface T h e m ine co v er an
area vvith llOOm in Iength an d 180m in vvidth
T h e size o f th e o re b o d ie s an d su lfu r content
d e c re a se d ow n w ard M ain m in eral o f these
b o d ie s is p y rite an d pyrotine
B y m in erallo grap hical an aly sis, m ost o f
pyrite cry stals p o ssess sem i-eu h ed ral, 0,2 -
2 ,5 m m in size, 53% in coeíTicient o f reílection
T h ey o ccu r in fo rm o f ch ain s w h ich are
d isp ersed an d clearly distin g u ish ed from host
rock Som e p y rites s u íĩe r from lim onitzation
(F ig 2,3) O re ch ara cterized dissem inated
stru ctu re; T h ese o re co n sists o f 30% p y rite Ihe
rest are non -o re m inerals
T h e re are 2 ty p es o f pyrite, fresh and
w eathered o re T h e m ạịo rity b elo n g s to the íirst
one Fresh p y rite lo cates bclovv th e w a te r table
and p o ssesses hig h c o n te n t o f su lp h u r (> 30% )
D ue to the p resen t o f w ater tab le, at th e to p o f
ore bodies, pyrite ex ists in fo rm o f very fine
grain and u n co n so lid ated State m ixed vvith 30-
40 % o f clay m in erals D o w n w ard , th e pyrites
are m ore rigid T h ey o c c u r m ain ly in m arb les in
form o f d issem in atio n w ith su lp h u r co n ten t less
than 30%
W eathered p y rite ores form ed a 5-45 m thick lay er c o n sistin g o f lim o nite w ith the
co n ten t o f Fe o v e r 40%
A verage c o n ten t o f su lp h u r in o re d ep o sits
is abo ut 2 4.4 5%
Fig 2 Beaded assemblage o f pyrite (sample GL.01)
3.2 The M in h Q u a n g p y r iíe m ìn e
It situ a tes in M inh Q u a n g co m m u n e, B a Vì
d istrict, H à Nội
C o-ord inate:
21°03 3 0 ” N ; 105°20 3 6 ” E
Fig 3 Semi-cuhedral pyrite (sample GL.02)
Trang 494 D M ai et aỉ. / VN U Ịournal o f Science, Earth Sciences 25 (2009) 91-97
T he M inh Q u an g p y rite m in e is a effusive
hydrotherm al o n es related to th e V iên N am
fo n n atio n (T|VW) co m p o sin g o f k o m atite in the
lovver p art an d trach ite, felsite in th e u p p er part
T h e deposits co n sists o f 4 o re b odies vvith 150-
850 m in length, 20 -150m in vvidth and 2-46.4m
in thickness M ain m in erals in th e ore deposits
are pyrite, p yro tine, ch alco p y rite and enargite
H ost ro ck suíTers from k ao lin itizatio n C ontent
o f su lp h u r o f o res ran ges from 4 0 6 to 45.75%
vvith 14.11% average
U n d er th e m inerallo g rap h ic m icro sco pe, 2
generations o f pyrite w ere id en tiíìed T h e first
one is ch aracterized by ap h an itic te x tu re vvith
u n clear boundary T h ey fo rm s th e m atrix or
groundm ass c o v e rin g 6 0 % o f the po lished
sam p les u nd er-in v estig atio n T h e second
generation is ch aracterized by fin e g rain s and
clear bound ary o f b an d s se ttin g up a net o f
pyrite crystals on th e m atrix (F ig 4)
Fig 4 2 genesis Pyrite (sample MQ.01)
4 A n aly sis re s u lts a n d d isc u ssio n
T h e co n ten t o f A s, C u, Pb, Z n elem en ts in
soils and vvater are p rescn ted in th e tab le 1
T heir d is trib u tio n w ill be d iscu ssed in th c next paragraphs
Table 1 Content o f eỉemenls
W ater samples (mg/1)
Soil samples (ppm) GL-8Đ
GL-12Đ GL-13Đ
8.559 9.948 9.201
No data
No data
No data
No data
No data
No data
No data
No data
No data
4.1 A rse n ic
A rsen ic c o n le n t in the vvater sam p les ranges from 0 0 0 2 to 0 0 4 8 mg/1 th a t is under the pollution th re s h o ld resp ect to surface vvater acco rd in g t o th e su rfa c e vvater S ta n d a rd (TC V N
59 42 -1 99 5) In c o m p a riso n vvith th e surface
w a te r S ta n d a r d T C V N 55 02 -2 0 0 3 , a r s e n ic
content in so m e a n aly zed sam p les in G iáp Lai
d ep osit (G L 0 7 , G L 0 8 ), in B ứ a riv e r (G L 09) and in the R ed R iv e r (G L 12), are ov er S tan d ard
A rse n ic c o n te n ts o f the w a te r sam ples from
G iap Lai area a n d alo n g th e Red R iver are displayed in th e F ig 5 N o te th a t the B ứa River, com ing fro m th e G ia p Lai m in e, ílovvs to the Red R iver but th e arsen ic c o n te n t along Bứa
R iver is lo w e r than th a t o f sam p les tak en from the Red R iver T h is rev ea ls th at the high arsenic content in th e Red R iv e r’s vvater is nol link directly to th e G ia p Lai m ine
A rse n ic c o n tc n t in the soil sam ples taken from sam e a re a v arie s from 8.6 to 9.2 ppm In
co m p ariso n vvith th e av erag e arsenic content in
Trang 5D M a i et al. / V N U Ịoum al o f Science, Earth Sciences 25 (2009) 91-97 95
the w o rld soil, th e sc v a lu c s a re ap p ro x im ately
d o u b le Hovvever, it is sy m p to m a tic po llu tio n in
acc o rd a n c e vvith C an ad ian S ta n d a rd vvith T E L
co -e ffic ie n t ap p ro x im ately e q u al 1.2 S im ilar to
vvater sam ples, the a rse n ic c o n te n t o f th e soil
sa m p le s taken from th e rig h t b a n k o f the Red
R iv e r is also hig h er th a n th o se ta k en from the
G ia p Lai m ine T h e su ch v a ria tio n o f arsen ic
c o n te n t in th e vvater an d soil en v iro n m en t
rev ea ls th at th e so urce o f a rs e n ic p resen te d in
the R ed R iver is e v e n tu a lly link to the
\veath erin g in th e u p p er co u rse
T h e arscnic co n ten t in sa m p lc s collected
from h o u seh old vvclls in th e M in h Q u an g and
G iá p Lai a r e a s is lovver th an t h a t o f S ta n d a rd
P arado xically , the a rse n ic c o n te n t in vvater
sam p les at th e M inh Q u a n g ex p lo ita tio n site is
very low rang in g from 0 0 0 2 -0 0 0 6 mg/1 T w o
ty p ical sam p les have b een se le c te d to analyze
S am p le M Q O la taken fro m tra n s p a re n t and
cle a r w ater has arsen ic c o n te n t s m a lle r than that
o f M Q O lb taken from y e llo w w ater The
reason o f th is d iíĩe re n c e is u n clear H ow ever,
the p o ssib le e x p la n a tio n s lin k to th e a b s o r p ti o n
o f arsen ic elem en t b y fc rric (III) iron hyd ro xiđe
Fig 5 Variation o f arsenic content in vvater along
the colỉected sam pỉe sections
4.2 C o p p er
T h e co n ten t o f C u in th e vvater sam ples
collected in th e stu dy a re a ra n g e s fro m 0 0 05 to
5.748 m g/l T h e h ig h e st v a lu e m e asu re d in the
sam ples co llecled in slre a m s at th e M inh Q u an g
m ine is 5 tim e s hig h er than th a t o f Standard
T C V N 59 42 -1995 F ortu natcly, th e C u content
in sam p les co llected in household w ells is in safe range
T h e C u co n ten t in sam ples collccted in stream s an d h o u sehold vvells in the G iáp Lai area is lo w er than 0.5 m g/l except one sam ple
G L 08 (2 m g /l) collected rig h t at the dum ping ground
T h e C u c o n ten t o f the sam ples (G L 02,
G L 04 , G L 0 7 , G L 0 9 , G L 1 2 ) collected from
G iap Lai m in e to th e Red R iver through the
B ứ a R iv er ten d s to increase tovvard th e Red
R iver (F ig 6 )
4.3 L e a d
In th e a re a o f the M inh Q uan g m ine, the
co n ten t o f P b in th e w ater sam p les ranges from 0.007 to 0 0 8 8 mg/1 It is vvorthy th at tw o sam ples M Q 0 4 taken from a household w ell and M Q O la tak en from M inh Q u an g sừ eam
h av e Pb c o n te n t are 1.5 and 8 tim e respectively
h ig h e r th an th at o f th e S ta n d a rd TC V N 5502- 2003
T h e c o n te n t o f Pb in alm o st o f th e w ater sam p les c o llected in th c G iap Lai m ine is low er than 0.01 m g/1 an d stỉll safe condition Hovvever, o n e sam p le co llected a t th e dum ping
g ro un d h a s lead co n ten t as high as 7.118m g/l
T h e Pb c o n te n t ten d s to increase alo ng the
ru n n in g c o u rse o f th e B ứ a R iver to th e R ed
R iv e r (F ig 6 )
Fig 6 Variation o f Cu, Pb and Zn contents in vvater
along the coỉỉected sample sections
Trang 696 D Mai et al. / V N U Ịoum al o f Science, Earth Sciences 25 (2009) 91-97
4.4 Z in c
T h e co n ten t o f Z n in vvater sam ples
c o llected in th e M inh Q u an g stream s is as high
a s 2 6 -2 8 m g /l w h ile th e Standard T C V N 5942-
1995 for d rin k in g w ater is o n ly lmg/1 T h e
sam p le co llected in a h o u seh old vvell has the Zn
c o n te n t 0 22 5m g/l and b ein g still u n d er the
S ta n d a rd
In th e G iáp Lai area, th e Z n c o n ten t in the
w a te r sam p les is lovver th an lm g /l and bein g
still u n d e r th e S tandard T h e Zn c o n ten t in the
vvater sam ple co llected from th e R ed R iv er is
0 6 mg/1 T h u s, th e co n ten t o f Zn ten d s to
in c re ase from the B ứa R iv e r to th e R ed R iver
(F ig 6)
H eav y m etals such as A s, C u, Pb, Zn
p resen te d in w ater o f th e stu d y areas m ay be
linked to th e ox idatio n o f su lfid es in thẹ
fo llo w in g m anner:
[M ]S + 0 2 -> [ M ] S 04
W h ere M den ote to h eavy m etals
T h e so lu b ility o f sulfates is m uch h ig h er
th a n th a t o f su lfides, esp ecially Z nS Ơ4 and
C11SO 4, fo r exam ple th e solubility o f Z n S 0 4 is
5 0 0 0 0 tim es h ig h e r than th a t o f Z nS , the
so lu b ility o f C u S 04 is 4 00.000 tim es higher
th an th at o f C uS Hovvever, th e lead su lía te is
q u ite d iíĩìc u lt to d isso lv e (th e solub ility o f
a n g lezite is 1.3.10*4 m ol/l) It is the scien tiíĩc
b ase to ex p lain th e ex isten ce o f th e C u an d Zn
a n o m a lie s in th e M inh Q u an g m ine w h ile the
c o n te n t o f Pb is n o t v ery high In the
en v iro n m en t c o n tain in g ferric (III) iron
h y d ro x id es, the form o f ex isten ce o f A s
( F e A s 04.2H 20 ) o n ly d isso lv es in acid
e n v iro n m en t T h is m ay be th e reason fo r the
low c o n ten t o f A s in th e w a te r en v iro n m en t o f
th e stu d y area
5 C o n c lu sio n s
T h e re su lts p resen ted in th is pap er te n d to
fo llow ing co n clu sio n s:
i In th e stud y area, the arsen ic c o n te n t in vvater e n v iro n m e n t is relativ ely lo w an d still
u n đ er the p o llu tio n thresh old b u t sy m pto m atic
p o llution in th e soil
ii T he c o n ten ts o f C u and Z n are h ig h e r than th at o f P b in vvater sam p les In som e p laces they form high an o m alies w ith con ten ts ov er
th e p e r m i s s i o n b y t h c Standard
iii T h e fact th at high c o n te n t o f h eavy
m etals in th e Red R iv e r’s w ater w hile low
co n ten ts o f h eavy m etals in th e m in e ^ vvater suggests th a t th e arsenic an d o th er h eavy
m etallic p o llu tio n in th e un d erg ro u n d w a te r o f
th e Red R iv e r plain is ev en tu ally com e fro m the Red R iv e r u p p e r course
iiii H eav y m etals such as A s, C u, P b , Zn presented in w ater o f th e stu d y areas m ay be linked to th e o x id atio n o f su líìd es
D ue to the lim itation o f actual data, the ten tativ e co n clu sio n s sh ou ld be íu rth e r
im proved
A ck n o v v led g e m en t
T h is p a p e r w as co n d u cted b ased on support
o f the b a sic research prọịect C o d e N o 70.38.06
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