Tap chi Khoa hoc Cong ng'^e \ong nghiep Viet Nam - So 9( !0o' •2019
It H6ng Lich, Vd Thj Kim Oanh, 2016, 2017, 2018. canxi, magie trong nUdc theo, phUdng phdp chuan Bao cdo kit qua quan trdc vd Phan tich Mdi trUdng dp EDTA.
dll vung lay Nguyin vd Nam Trung Bp, nhi|m \-u Tieu chuan Viet Nam. 2000. TCVN 6638:2000. Tieu hang nam. chuln Qude gia ve Chit Iflpng nude - Xac djnh Tilu chuln Vi^t Nam, 1996. TCVN 6180-1996. Tilu ^ " ^ " ^ ° '^'^ ^da xuc tie sau khi khfl bdng hpp kim
chuln Qude gia ve Chit Iflpng nfldc - Xac dinh NO
irong nfldc theo, phfldng phap trdc phd dung axil Tilu chuln Viet Nam, 2000. TCVN 6196-3:2000. Tilu sufosalisilic chuan Quoc gia vl Chll lupng nfldc - Xic djnh kali long so trong nfldc theo, do pho phat x^ ngpn Ifla.
Tilu chuln Vi|t Nam, 1996. TCVN 6202:1996. Tieu
Tieu chuan Viet Nam, 2008. TCVN 6663-3:2008. Tieu chuan Quoc gia vl Chit lupng nUde- Xdc dinh ^^uln Quoc gia vl'chltlupng nUdc-Hfldng dan phospho tong so trong nfldc theo, phfldng phap trae bdo qudn vi xd ly mdu.
phi dung amoni molipdat. Tieuchuan Viet Nam, 201I.TCVN 6663-1 l:2011.Tilu Tieu chuln Vi^t Nam. 1996. TCVN 6198:1996. Tilu chuan Quoc gia ve Chit Iflpng nfldc - Hfldng dan lly
chuan Quoc gia vl Chit lUdng nUdc - Xdc dinh mau nUde nglm.
Nutrient leaching and risk of groundwater pollution in crops cultivation in the Central Highlands
Vo Thi Kim Oanh, Le Van Hoan Abstract
Leaching of nutrients takes place strongly on flat land, where there is heavy rainfall, a lot of watering like coffee, pepper, vegetables,... where soil is porous, highly drained. Nutrient leaching takes place quietly but is considered to be the third risk of land degradation after floods and droughts. Nutrient leaching levels are ranked in order K> Ca, Mg> N> P. The amount of nutrients washed away at the 60 cm level is very high, with the total amount of water collected from the lizimet system over 5000 m'/ha/year and the amount of nutrients washed away is up to 112 kg K equivalent to 225 kg KCl or enquivalent to 250 1^ of Potassium Sulfate (K,SO^); 80 kg N equivalent to 17-11^ Ure or enquivalent to 380 kg SA (Sulfate Amon). The amount of nitrate (NO') obtained in some groundwater wells in vegetable growing areas in Lam Dong varies from 6.8 to 177.9 mg/l. Beyond 9.9 - 11.9 times compared to QCVN 09-MT: 2015/BTNMT for water used for domestic purposes and exceeded 17.79 times in column Bl and 11.86 times in column B2 of QCVN 08-MT: 2015/BTNMT on water used for irrigation purposes. This is the cause of ihe risk of making the groundwater environment polluted.
Keywords: Washing away, soil degradation, lizimet, groundwater pollution
N^ay nhgn bdi: 20/8/2019 Ngfldi phan biln: PGS. TS. LI Dflc Ngay phin bi|n: 1/9/2019 Ngay duylt dang: 9/9/2019
NGHIEN CUtJ H O A N THO VA PHUC HOI MOI TRl/OiNG TAI Dir A N KHAI T H A C B A U X I T E N H A N CO - DAK NONG
Vuong The Hoan', Le Hong Ljch', Pham \ ^ Hieu' T O M TAT
Hodn thd vd phuc hdi mdi trfldng trong khai thic khoang sin Id nhiem vu bat budc phii thUc hi|n tai Vi|t Nam.
Dy an khai thdc bauxite Nhan Co - Dak Ndng cd quy md di|n tich todn md la 3.074 ha va thdi gian khai thic la 30 nam (gily phep so 2624/GP-BTNMT, ngay 11/11/2016), dp dung cdng nghe khai thdc Ip thiln. Qua trinh khai thic gom nhflng cdng vi|c chinh la khai hoang, bdc tach Idp phii be mat, thu quang va san lap hoan tho. Nhflng ho^t d^ng ndy si gay ra nhflng tdc dpng nhit dinh den mdi trfldng nhfl xdo trpn. phi vd kit ciu cae tang dit, thay ddi dja huih. xdi mdn.... Do dd, cong tic hodn thd va phyc hdi moi trfldng cdn phii dflpc chu trpng va thflc hi|n song song vdi hoat dpng khai thac theo phfldng thdc cudn chieu. Tinh din hit nam 2018. dfl an da khai thic gin 120 ha
\ i tiln hinli hodn tho, trong keo lai trln 90% di|n tich, ti le cay song sau 02 nam trdng dat 88,7%, chilu eao quin thi trung binh dat 156,0 cm.
Tfl khda: Hodn thd. phuc hoi mdi trUdng, cdy keo lai, bauxite
'Trung tim Nghien edu & Quan trac mdi trUdng ndng nghiip miln Trung vi Tay Nguyin, Vi|n Mdi trUdng N6ng nghiip
.' r 'Ml Nam - 56 9( 1061/2019
I. DAT \ AN DE
Khai thdc tdi nguyin thiln nhien phuc vy phat triln kinh tl dat nude da \a dang dflpc nhieu nfldc trln thi gidi quan tdm vd Uu tiln ddu tfl, trong dd cd
\'iei Nam Tuy va\. khai thac tdj nguyin ndi chung vd khai thdc quang bauxite ndi rilng da vi dang Idm ndy sinh nhieu he lyy ddi vdi mdi trddng. Do do, cdng tdc hodn thd va phyc hdi mdi trfldng sau khai thac Bauxite dang Id van de dflpc cac nhd qudn ly.
cae nhd khoa hpe vd ngfldi dan dac bill quan tdm.
Theo De dn cai tao phuc hdi mdi trfldng dfl an khai thic md bauxite Nhdn Cp - Dak Ndng (2013) ben c^nh cdc tac dpng tich cflc. hoat dpng eua khai thdc md cung se gay ra nhflng tie dpng tieu cflc doi vdi mdi trfldng tfl nhiln vd mdi trfldng xa hdi cda khu vyc md vd vung phy can. Dia hinh. canh quang khu vflc md se hi biln ddi nhilu, bl mat cua khai trfldng md sau khi kit thuc thi khdng cdn tham thflc vat bao phd, \\ vdy vdo mua mfla se xay ra hiln tflpng xdi mdn dat gdy bdi lap khu vUe, hi thdng khe suoi.
Xuit phdt tfl van dl dd. nghiin edu dinh gii "Cong tic hodn thd vd phuc hdi mdi trUdng tai du an khai thac Bauxite Nhdn Cd - Ddk Ndng, giai d o ^ dau khai thac (2016 - 2019)" ddpc tien hdnh nham ddnh gia khi nang hodn tho, tdi sd dyng dat sau khai thdc bauxite cua dfl in.
II. VAT LlEUVA PHirONG PHAP NGHIEN CCfU 2.1. Vat U|u nghien cflu
Mdu dit trUdc khai thdc bauxite vd dat da hodn thd, cay keo lai.
2.2. Phfldng phdp nghien cflu
2.2.1. PhUdngphdp thu thdp tong hpp tdi lieu Thu thdp va chpn lpc cic tai li|u vl chUdng trinh hodn tho. phuc hoi mdi trfldng sau khai thdc bauxite liln quan den pham vi khu vflc nghien eflu.
2.2.2. PhUdngphdp lay mdu thUc dia
T^ khu vflc dia diem nghien cflu tiln hanh khao sit vd lay mau dat hodn thd (trfldc va sau khi trdng cay keo lai) d ede ting dat (0 - 30 cm. 30 - 60 em).
Mau dat dflpc thu thdp theo Tieu chuan Viet Nam vl chdt lflpng ddt - lay mau - ylu edu chung (TC\'N 5297.1995/BKHCNMT). va bdo quin theo Tilu chuan \'i|t Nam vl chat Iflpng dat - lay mau O W N 5960:1995/ BKHCNNH ).
2.2.3. PhUdng phdp phdn tich mdu
.Mdu dat dflpc phdn tich theo tilu chuan Nicl Nam va tieu chuan nganh hiln hanh. Ddm bdo chat Iflpng va kiem sodt dial lfldng phdn tich mau theo QA/QC.
Cdc chi tieu phan tich gom: Dung " ^ trpng, dd xdp; pH^^,. OC long sd. N ti'"'" ^ ' ^ ^.
tieu, K,0 de tieu. Ca^*. Mg-*, C¥X' " ' *•
cdc phUdng phdp phdn tich tUdng ' ^^"•
TCVN 11399-.2016; TCVN5979-2007; Tt * 'H:20II;
TCVN 6645:200ft TCVN 8942:2011; TC^ • •<52:2011;
TCVN 8569:2010; TCVN 8568:2010 vd TX • N 8246:2009.
2.2.4. PhUdngphdp theo doi tinh hinh >• h tnidng cua cdy keo lai
Dim so cay song, do chieu cao cdy theo 04TCN 132:2006 tai cac thdi diem 06 thang; 12 thdng vd 22 thdng.
2.2.5. PhUdng phdp xiJC ly so lieu
Theo cdc phfldng phap thdng kl thdng thfldng, cdc gid tri trung binh dfldc tinh kem vdi dp I|ch chuan, sd dyng cdc hdm tfldng quan trong phan mim Excel.
2.3. Thdi gian va dia diem nghien cdu Nghiin eflu diioc thflc hien tfl thang 01 nam 2016 den thdng 06 nam 2019 tai khu v\£c dat khai thdc bauxite tai thdn Quang Sdn, xa Nghia Thing, huyen Dak RTap, tinh Dak Ndng thupc dfl dn khai thac bauxite Nhdn Cd - Ddk Ndng.
III. KET QUA VA T H A O LUAN
3.1. Quy trinh hoan th6 vd trong keo Iai tai d^ an khai thdc bauxite Nhan Cp - Dak Nong
Theo De an cai tao phuc hdi mdi trfldng dfl an khai thac md bauxite Nhdn Cd - Dak Ndng (2013):
Md dp dung phUdng phap khai thac cuon chieu kit hpp vdi hoan tho. Ldp dat phu bdc d khu vflc khai thac tilp theo se dflpc do vao khoang khong gian da khai thac de hoan thd. Nhfl vdy, khi ket thdc khai thdc be mat khai trudng dd dfldc do ldp dat mdu Iln trln bl mat vd dia hinh khai trfldng si gan tfldng tfl nhfl ban dau nhflng thap hdn khoang 3 - 4 m. Lfla chpn cay giong cd tuoi tfl 2,5 - 3 thing tuoi, chilu cao eay khoang 25 - 30 em, khdng gdy ngon, sinh trfldng tot. Ho trdng cay cd kieh ihudc (0,4 1 4 x 0 4 m) cac hd trdng dflpc ddo ,o ie nhau. Sau dd tiln hdnh trpn phan yi smh vdo da> ti le 1/40 d l bdn lot, trong cdv d i n t l ? ' " ' '7- '^'-'^ '^'"' ^ham sde tfldi cay dmh ki irong nam dau din khi cay phat triln 6n dinh. Hang nam tien hdnh trdoE d J Z l Z nhflngcaychlthodckhdngcdkhdndlg;^,^^^^^^^^^^^^
Den het nam 2018, du an khai thac R=, •. v,,..
C « . D a k N 6 „ g d a . h U c h i e „ U , a . t ' ™ ! f " "
fen hanh hoan tha. trong cay keo la, . ^ ^ 'Z^-' tich vdi mjt dp trong 1.660 cay/l.j (S6 r . ° '''^"
va M6i tnJdng tinh Dak Nong, 201B,, ^nuyen 96
D chi Khoa hoc Cdng nghe Nong nghiep V7lt Nam - 5(5 9{106}/2019 3.2. D$c dilm phau di|n vd tinh chat ly, hoa hpc
dit trfldc khai thdc bauxite
Theo Ngd Thj Bio Minh, LI Hdng Ljch (2013), kft qua phdn tich vung dat thudc khu vue quy hoach khai thic Bauxit tai Nhdn Cd, Dak Ndng tai bang 1 vd bdng 2 cho thay: Dat cd phdn dng kha chua loan phdu di|n, pii^ci ^ ^^^ "-^B ^'^" ^^"8 t^ '^•^ " 5'^' hdm lfldng cac chdt OC, N, Pp^, Kp, Ca^% Mg-' va dung tich hap thu (CEC) 6 tat cd cdc tang deu thap vi thupc hang ngheo, ham Iflpng Fe^Oj, Al^O^ cao.
Thanh phan cd gidi tfldng doi nang tuy ty Ie set va thit tfldng dfldng nhau (xap xi 40 - 50%) nhflng do dll ed nhilu kit von, da ong nln qua thdi gian sfl lang chdt da 1dm cho dat chat cflng, dp xop thap. Nhflng viing dat hoang hod, thflc vdt ehi cd cd chi, ed me, cdy byi nhd,... thdnh phin cd gidi it ed gia tri ndng hpe do kit eau dit hi phd vd, ly tinh dat suy thoai, kha nang gifl nfldc, gifl phdn, thodt khi trong dat kem.
Bang I. Mpt so tinh chit vat ly ciia dll trfldc khai thdc bauxite Phau
dien Tang (cm)
Dung
Ty trpng D^ xop g/cm^
P D l
PD2
PD3 0 - 30 60 0 - 30 60 0 30 60
30 cm - 6 0 cm - 9 0 cm 30 cm
• 6 0 cm - 9 0 cm 30 cm - 6 0 cm - 9 0 cm
1,33 1,37 1,42 1,30 1,35 1,44 1,47 1,52 1,52
2,58 2,62 2.63 2,42 2.47 2,52 2,59 2,63 2,66
48,45 47,71 46,01 45,67 40,89 39,68 43,24 42,21 42,86 Nguon: Ngd Thi Bdo Minh, Li Hong Lich (2013).
Bang 2. Mpt so tinh chit hda hpc eua dit trudc khai thac bauxite (tang 0-30cm)
MMl MM2 MM3
PHKC, 5,31 5,31 4,68
0 C ( % ) 1,57 1,31 1,89
N ( % ) 0,056 0,063 0.156
P , 0 , KjO mg/lOOg 3,95 5,48 2,43 1,51 2,59 3,50
Ca"*
0,50 0,25 0,18
Mg"*
Cmol-'lcg 0,05 0,28 0.27
CEC
8,5 13,4 15,7
Fe^Oj A 1 , 0 , 14,1 21,6
(%)
13,2 29,3 17,7 8,8 Ngudn- Ngo Thi Bdo Minh, Li Hong Lich (2013).
3.3. Ddc diem phau diln va tinh chat ly, hda hpc ddt hoan thd trfldc vd sau 2 nam trdng keo lai
Kit qud quan trdc, phdn tich dat hoan tho trUdc vi sau 2 ndm trong keo lai tai dia diem nghien cdu nhu sau:
0 nhflng vung dat mdi hoan tho ed dai va cay keo lai cdn non vd thfla, thdm phu thdc vdt mdng, kit cau ddt rat rdi rac, tinh hinh xdi mon be mat xay ra
rat manh, ddc bill Id nhflng vung dat co dp doe Idn (> 5*), sfldn doc ddi ((> 50 m). Xdi mdn tao thdnh rdnh sau va xuat hien khd nhilu trln be mat dat. Tuy nhiln trln nhflng khu dat hoan tho da dflpc trdng keo lai va cd dai mpc day td > 2 nam thi tinh trang xdi mdn gidm dang kl, mdt dp va dp sau rdnh xdi mdn giam tfl 60 - 70% so vdi dat mdi hodn thd.
Hinh 1. Dat mdi hoan tho thdm thflc vdt it, bi xdi mdn manh Dat hoan tho bi nln chat manh (dung trpng =
1,43 g/cm*). cd ddc tinh chua; ham lfldng hflu cd trung binh. dam tong s6, Idn de tilu, kali de tilu va
cdc cation kiim tho (Ca'*, Mg^*) vd dung tich hap thu (CEC) rat ngheo.
i - ' W l -•• \a"'-
"V "*
Hinh 2. Dat hodn tho va trong keo lai 22 thdng
TT
1 2 3 4 5 6 7 3 9 10 11
Bang 3, Tinh chat 1\
Chi tieu
Dung trgng (g/cm^) Tl trong Dp xop (%) PHKO O C ( % ) N(%) Pdetieu(mg/100g) Kile tieu (mg/lOOg) Ca"* (Cmol/kg) Mg- (Cmol/kg) CEC (Cmol/kg)
hoa hoc dat hoan tho Tnldc trong
keo 0-30 30-60
cm 1.43 2,61 45,2 5,12 1,39 0,081 2,49 2,96 0,26 0,18 5,0
cm
5,08 1,25 0,077 2.42 1,83 0,24 0,10 4,8
Sau 2 nam trong keo 0-30 30-60
cm cm 1,39 2,61 46,7 5,14 5,11 1,42 U l 0,084 0,077 2,11 2 J 6 3,17 1,99 0,26 0.22 0.24 0,18 4,6 4,4
Dat hodn tho sau 02 nam trdng keo lai dung trpng giam tfl 1,43 xuong cdn 1,39 g/cm' so vdi dat mdi hodn tho nhflng khdng dang ke. Ham Ifldng hflu cd cd tang nhe (tang 0,03%), do bdn phdn hflu cd vi sinh (2 tan/ha) vd Iflpng cd dai cat bo tai chd hdng nam; dam tong so, lan de tilu, kali de tilu vd ede cation kiem, kiim tho (Ca^% Mg^*) vd dung tich hap thu (CEC) van dang d mflc rat nghlo.
Vd Thi Kim Oanh (2013): Khai thac khodng sdn trong dilu kiln dia hinh bi chia cat manh, dp doe cao cung vdi Idpng mfla Idn (>2000 mm/nam) vd tap trung thi nguy cd xdi mdn, sat Id dat la khd tranh khdi. Ke ed khi dat dflpc hoan tho trd l^i sau khai thdc quang thi cae tinh chat vat ly, ket dinh trong dit chfla the phyc hdi, tham thflc vat trln mat dat chfla dflpc tai tao cdng lam eho nguy cd xdi mdn, rda trdi dat trong mua mfla nghiim trpng hdn.
Hinh 3. Phau diln ddt mdi hodn tho 3 thing, chfla trong ciy. cd it
Ghi chu: Tdng 0 - 90 cm- ddt hodn tho, mdu sdc khi kiid dong nhdt, lan nhieu kit von. re vd thdn cay nhd, kit cdu rdi rac: Tdng 90 - 120 cm: ddt nguyin trgng mdu hdi sdm. khdng cd re cdy. rat chdt.
Hinh 4 I'hai; .ii. dit t!".' • :6 quang 1 Ghi chii. Tdng 0 20 cm r.
miin: Tdng 0 • 95 cm: mdu he;, \ Tdng > 95 cm: ddt chdt, min.
^g«y^^-.angtr6nghotilu.
nhiiu ' xop;
: :h!Khoa hoc Cong ngh^ Nong n j - eo Viei Nam - So ^( !06}/2019
3.4. D^c dilm sinh trfldng cua cay keo lai tai vung nghiin cflu
Kit qua theo ddi mpt sd ehi tilu sinh trfldng ciia cay keo lai trln nen dat hodn tho sau khai thac bauxite t?i Nhdn Ca cho thay: Ty 11 eay sdng sau 02 nim trong trung binh khoang 88,7%, chieu eao trung binh cua quan the sau 06 thdng la 69,5 cm;
12 thing Id 94,8 cm vd sau 22 thing la 156,0 cm. Nhfl v^y, cdy keo lai ed kha ndng sinh trfldng kha tot trln nln dat hodn tho sau khai thdc bauxite.
Bdng 4. Die diem sinh trfldng cua cay keo lai Thdi gian sinh trfldng Die dilm sinh trfldng (thdng)
cua cdy keo lai — — Di^n bien ty 1? song ciia
k<»lai(%)
Chi^u cao cua keo lai (cm) 06 92,3 69,5
12 90,1 94,8
22 88,7
1
156,0
dung quy trinh hodn tho vd cai tao dat sau khai thic bauxite mpt each hpp !y thi hoan toan ed khd nang dfla vao sfl dung tai canh tac cic loai cdy ndng, lam nghiep cd gia tri cao sau 1 - 2 ehu ky trdng keo lai.
T A I U £ U THAM KHAO
Bp Khoa hpc Cong nghe va Moi trfldng, 1995. Tilu chuln Vilt Nam ve chat lupng dll - lay mau (TCVN 5960:1995/BKHCNMT).
Bp Khoa hpc Cong nghe vi Moi trfldng, 1995. Tilu chuln Viet Nam vl chat Iflpng dat - lay mau - yeu eau chung (TCVN 5297:1995/BKHCNMT).
Bp Nong nghiip vi PTNT, 2006. Tieu ehuan nginh vl bieu sinh trUdng vd sdn lUpng tam thdi rflng keo lai trong thuan loii (04TCN 132:2006).
Ngd Thi Bdo Minh, LI Hong Lich, 2013. Mpt S(") tinh chit moi trudng dit vung dfl an khai thic bauxit tai Nhan Cd, Dak Ndng. Tap chi Ndng nghiip vd Phdt trien ndng thdn, so thing 3/2013: 99-103.
Sd Tdi Nguyin vd Moi trfldng tinh Dak Nong, 2018.
Bao cdo hi|n trang Du an nhd may Alumina Nhin Cd (so 131/BC-STNMT-KS, ngiy 15 thing 5 nam 2018).
Tap doan Cong nghiep Than - Khoing sin Vi|t Nam, 2013. De dn cdi tao, phyc hoi moi trudng eua Du dn dau tu xiy dflng eong trinh khai thac md Bauxite Nhdn Co - Dak Ndng (Quylt dinh s6 2144/QD - BTNMT ngay 06/11/2013 ciia BO Tdi nguyin vd Mdi trUdng).
Vo Thi Kim Oanh, 2013. Nguy cd xdi mdn, sat Id dll d vung du an khai thdc bauxit tai Nhdn Cd, Dak Nong. Tap chi Ndng nghiep vd Phdt trien ndng thdn, sd thing 3/2013: 109-112.
IV. K£T LUAN
Din hit nam 2018, dfl an khai thac Bauxite Nhan Cd - Ddk Ndng dd thflc hien khai thdc gan 120 ha va tiln hdnh hodn tho, trong cdy keo lai trln 90% diln tich vdi m^t dp trong 1.660 cdy/ha.
Dat hodn thd sau khai thdc bauxite thdi gian dau bj xdi mdn m^nh do thdm thdc vat it, ham Iflpng cdc yeu t6 dinh dddng nhfl N, P, K, Ca, Mg ngheo. Tuy nhiln, tinh hinh sinh trfldng cua cay keo lai trong Irin nln dat hodn th6 sau khai thdc bauxite rIt khd quan. cd ti le sdng sau 02 nam d^t 88,7%, chilu cao quan thi trung binh dat 156,0 em. Do dd, nlu ap
Soil remediation and environmental rehabitation at the bauxite mining project site Nhan Co - Dak Nong
Vuong The Hoan, Le Hong Lich, Pham Van Hieu Abstract
Soil remediation and environmental rehabitation are obliged to be implemented in Viemam. The bauxite mining project Nhan Co -Dak Nong has a total area of 3,074 hectares and its mining time is 30 years (Licence number 2624/GP-BTNMT, 11/11/2016), which applies surface minflig technology. The minmg process consists of the main tasks of reclaiming, dissection of surfece coatings, ore collection and a complete leveling. These activities cause certain impacts on the environment such as dismrbanee, structural disruption of soils, terrain changes, erosion....
Consequendy, soil remediation and environmental rehabitation are paid attention and implemented in parallel with the mining activities. By the end of 2018, the project has been exploited nearly 120 hectares and conducted soil remediation and grew Acacia trees over 90% of the mined area; the proportion of Uvjng trees after 02 years of the planting was 88.7% and the average height of populations height reached 156 cm.
Keywords: Bauxite, soil remediation, environmental rehabitation. Acacia Ngiy nhdn bai: 22/8/2019
Ngay phdn bi|n: 2/9/2019
Ngfldi phdn bien: PGS. TS. Pham Quang Hd Ngdy duylt ddng: 9/9/2019
