mk17_environmental water demand of the srepok catchment_vietnamese.pdf

VIN QUY HOCH THY LI

KH NNG NGUN NC S DNG NC V KHUYNH HNG LU VC SNG SREPOK

BO CO

HIN TRNG MI TRNG NHU CU NC CHO MI TRNG

V TM QUAN TRNG CA VIC DUY TR DNG CHY MI TRNG

LU VC SNG SREPOK

H Ni, 2013

MC LC

1. Hin trng cht lng nc mt lu vc sng Srepok....................................................1

2. Hin trng cht lng nc ngm trn lu vc: ...........................................................12

3. Nhng vn mi trng chnh trn lu vc sng Srepok. .........................................37

3.1. Tc ng ca thy in n mi trng. ..................................................................... 37

3.2. Tc ng ca pht trin kinh t, x hi n mi trng: ............................................ 45

4. C s la chn yu cu v phng php tnh ton nhu cu nc dnh cho mi

trng trn lu vc. ..............................................................................................................47

5. Tm quan trng ca vic duy tr lng nc cho mi trng trn lu vc. ..............48

6. Phn tch d bo nhu cu nc dnh cho mi trng

1

1. Hin trng cht lng nc mt lu vc sng Srepok.

Sng Srpk l chi lu cp I ca sng M Kng, do hai nhnh Krng Ana v Krng Kn hp thnh. Dng chnh tng i dc, chy t cao 400m nhp lu xung cao 150m bin gii Campuchia. Theo bo co hin trng mi trng tnh k Lc nm 2010, cc im quan trc cht lng nc sng Srepok c gim st t nm 2002 2009 ti cc v tr sau:

Bng 1: Cc v tr quan trc trn lu vc sng Srepok

TT Sng V tr ly mu K hiu

1 Sng Srepok

Cu 14 DL1

Trm Thy vn Bun n DL2

Cu Ea Nhul DL3

2 Sng Krng N Cu Krng Kn DL4

3 Sng Krng Ana Cu Giang Sn DL5

Ngun: bo co hin trng mi trng tnh k Lak -2010 - pp:39.

Thng qua kt qu quan trc ca S Ti Nguyn Mi trng tnh k Lk trong mt thi gian di t nm 2002 n nm 2009, c th nh gi din bin cht lng nc lu vc sng Srepok theo thi gian ti cc v tr quan trc nh sau:

pH: Kt qu o pH ti cc v tr gim st cht lng nc sng Srepok dao ng khng nhiu, trong khong thi gian kho st t nm 2002 - 2009 trong khong t 6,2 - 8,1. Gi tr ny thp nht vo nm 2008 ti sng Krng Kn pH=6,2. Gi tr pH cao ti cu 14 v gim ti trm thy vn Bun n. Ti im quan trc sui Ea Nhul l ngun nc vo sng Srpk, pH quan trc c nm trong khong t 7,3 - 8,1. Kt qu quan trc cho thy pH cc v tr quan trc nm trong khong cho php ca QCVN08:2008/BTNMT- dao ng t A1 n A2.

Cht rn l lng SS v c: Nng cc cht rn l lng c kho st h thng sng Srepok dao ng rt ln gi ma ma v ma kh, dao ng trong khong t 11 - 163 mg/l, vt QCVN08:2008/BTNMT- A1 t 1 - 8 ln. Nng SS kh cao thng vo ma ma v cc t l qut, vo ma kh hm lng SS thng rt thp.

nhim hu c: ti cc v tr quan trc trn sng Srepok v sui Ea Nhul. Kt qu phn tch DO, COD v BOD5 trong khong thi gian t nm 2002-2009 c xu hng tng, nhu cu oxy sinh ha BOD5 ti cc v tr dao ng trong khong t 2-9 mg/l, hu ht u vt QCVN08:2008/BTNMT- A1 l

2

nhim kim loi nng: Kt qu phn tch kim loi nng nh St tng, ch (Pb), thy ngn (Hg), cadimi (Cd), Asen (As) trong nc sng Srepok v sui Ea Nhul cho thy cha c du hiu nhim kim loi nng. Cc v tr quan trc nng kim loi nng u t QCVN08:2008/BTNMT- A1.

Nng kim loi st (Fe) trong khong thi gian t 2002 - 2009 ti sng Srepok dao ng trong khong t 0,43-1,54 mg/l, cao nht nm 2006 v vt QCVN08:2008/BTNMT- A1 l 1,5ln quy nh

3


Hnh 3: Din bin hm lng DO t nm 2002-2009 lu vc sng Srepok


Hnh 4: Din bin hm lng BOD5 v COD t nm 2002-2009 lu vc sng Srepok

4


Hnh 5: Din bin hm lng N-NO3 & N-NO2 t nm 2002-2009 lu vc sng Srepok

Ngun: bo co hin trng mi trng tnh k Lak -2010 - pp:42

Hnh 5: Din bin hm lng N-NH4 P-PO43- t nm 2002-2009 lu vc sng Srepok


Hnh 6: Din bin hm lng Fe tng t nm 2002-2009 lu vc sng Srepok

5


Hnh 8: Din bin hm lng Coliform t nm 2002-2009 lu vc sng Srepok


Ghi ch: ng l Quy chun nc mt loi A1 (QCVN 08:2008)

Cc v tr quan trc trn sng Srepok gm c 3 v tr:

1. Sng Srepok ti cu 14 trn quc l 14.

y l v tr khng ch t thng ngun, cc khu cng nghip Tm Thng, Ha Ph v pha h lu cc nh my thu in Bun Kuop, Bun Tua Srah.

6

Kt qu gim st cht lng nc sng Srepok ti cu 14 cho thy: vo ma kh hm lng TSS tng i thp, gi tr thp nht o c vo ma kh thng 12 nm 2007 c hm lng TSS = 24 mg/l nm trong gi tr A2 ca QCVN 08:2008, hm lng TSS cao nht o c vo thng 7 nm 2007 hm lng TSS = 90 mg/l vt gi tr B1 ca QCVN 08:2008. TSS c xu hng gim dn t nm 2008 n nay do trn lu vc sng Srepok mt lot cc nh nh my thy in bc thang v ang i vo hot ng, hm lng TSS lng ng trong h cha, lm gim TSS trong nc sng. Gi tr DO ti cc thng kho st dao ng t gi tr A1 n A2 ca QCVN 08:2008. Tuy nhin hm lng DO c xu hng gim dn t nm 2009 n nay, DO cao nht o c vo thng 7 nm 2006 c gi tr l: 8,64 mg/l v thp nht o c vo thng 2 nm 2008 v 2009 c gi tr l 5,52 mg/l. Hm lng cc ch tiu nh COD v BOD5 c xu hng tng ln, hm lng COD cao nht o c vo thng 1/2010 c gi tr 15,7 mg/l, thp nht vo thng 8 nm 2006 v 2007 c gi tr 8,0 mg/l. BOD cao nht o c vo thng 7/2009 c gi tr 12,4 mg/l. Hm lng NH4+ c xu hng khng thay i nhiu trong thi gian gim st, tuy nhim hm lng NO2- c xu hng tng ln c bit l t nm 2009 n 2010. Thng qua kt qu gim st c th thy vo ma kh, khi lng khi lng nc n t, cht lng nc sng Srepok nhim hn so vi ma ma. V xu th din bin, hm lng cc cht gy nhim c s thay i xu hn so vi nhng nm trc v thng th cc thng ma kh ngun nc b nhim cao hn cc thng ma ma.

Din bin mt s ch tiu cht lng nc chnh sng Srepok ti cu 14 nh sau:

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Hnh 9: Din bin mt s ch tiu cht lng nc ti cu 14 trn QL 14 t nm 2006-2010

Ngun: Gim st cht lng nc sng Srepok trc khi chy sang Campuchia - Vin

QHTL -2010

2. Sng Srepok sau thu in DrayHlinh

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Kt qu quan trc t nm 2006 n 2010 cho thy xu th din bin hm lng TSS gim dn. Hm lng TSS thp nht o c vo 2/2007 c gi tr l 25 mg/l v hm lng TSS cao nht o c vo thng 7/2007 c gi tr l 90 mg/l. Trong nm 2010 hm lng TSS trung bnh c nm ch l 38,5 mg/l trong thng thp nht o c vo thng 4/2010 c gi tr 26 mg/l v thng cao nht o c vo thng 7/2010 c gi tr l 54 mg/l. Hm lng DO nhn chung cao, tt c cc thng kho st hm lng DO u nm trong gi tr gii hn A1 ca QCVN 08:2008, dao ng t 6 mg/l n 8,17 mg/l. Nguyn nhn hm lng DO cao l do v tr ly mu sau tubin ca nh my thy in DrayHlinh, do vy ngun nc c xo trn lm tng lng xy ha tan trong nc. Hm lng COD, BOD c xu hng bin i cao hn t nm 2009 n 2010, hm lng COD thp nht o c vo thng 12/2008 c gi tr 8,28 mg/l, hm lng COD cao nht o c v thng 11/2007 c gi tr l 19,0 mg/l, nm trong gi tr gii hn t A1 n B1 ca QCVN 08:2008. Hm lng BOD c gi tr thp nht o c vo thng 5 2006 c gi tr l 4,0 mg/l v cao nht o c vo thng 5/2009 c gi tr l 15,0 mg/l, nm trong gi tr t A1 n B1 ca QCVN 08:2008. Hm lng NH4+ c gi tr thp nm trong gi tr gii hn t A1 n A2 ca QCVN 08:2008 dao ng t 0,02 mg/l n 0,165 mg/l. T nm 2008 n 2010 hm lng NH4+ c xu hng tng cao hn so vi trc y. Thng qua kt qu phn tch cho thy cht lng nc cht lng nc trong thi gian gn y b nhim hn.

Din bin mt s ch tiu cht lng nc chnh sng Srepok sau thu in DrayHlinh:

9

Hnh 10: Din bin mt s ch tiu cht lng nc ti thy din Dray Hling 2006-2010


QHTL -2010

3. Sng Srepok ti trm Thu vn Bn n.

y l v tr khng ch ton b h lu ca tt c cc cng trnh thu in, cc khu cng nghip, th pha Vit Nam trc khi chy sang Campuchia.

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Kt qu quan trc cho thy xu hng chung ca dng chy sng Srepok t thng lu xung h lu, do tc ng t cc cng trnh thy din bc thang trn h thng, hm lng TSS ti trm thy vn Bn n c xu th gim dn, hm lng TSS bin i mnh theo ma, vo ma kh TSS thp nht o c vo thng 11 v 12 nm 2007 c gi tr l 20 mg/l, TSS cao nht o c vo ma ma, thng 6/2007 c gi tr l 90 mg/l. Hm lng DO c xu hng gim hn so vi v tr sng Srepok ti h lu thy in DrayHlinh, hm lng DO cao nht o c vo thng 7/2006 c gi tr l 8.17 mg/l, hm lng DO thp nht o c vo thng 2/2007 c gi tr l 5.9 mg/l. Hm lng cc cht nhim hu c nh COD, BOD5 c xu hng tng dn, hm lng COD o c c gi tr cao nht vo thng 8/2007 l 24 mg/l v thp nht o c vo thng 12/2008 c gi tr l 8.8 mg/l. Hm lng BOD5 c gi tr cao nht o c vo thng 10/2009 c gi tr l 11.2 mg/l v thp nht o c vo thng 5/2007 c gi tr l 4.2 mg/l.

Di y ld din bin mt s ch tiu cht lng nc chnh sng Srepok ti trm thy vn Bn n.

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Hnh 11: Din bin mt s ch tiu cht lng nc ti trm thy vn Bn n 2005-2010


QHTL -2010

nh gi chung v din bin cht lng nc sng Srepok

H thng sng Srepok trong nhng nm gn y c biu hin nhim bi cc cht hu c, cc thng s nitrit, nitrat cng c biu hin nhim do nc ma cun cc cht b mt theo dng nc xung sng, nc thi t sn xut, sinh hot hu ht khng c x l, thng xung gy ra nhim ngun nc mt. Hm lng cn l lng v c gim xung trong thi gian gn y. iu ny cng ph hp vi quy lut l mt lng ln cn l lng b lng ng trong lng h cha gy ra hin tng trn. i vi ngun nhim bi vi sinh vt c chiu hng ngy cnh tng v kh cao, nguyn nhn do hot ng thi cht thi sinh hot ca con ngi cha qua x l thi ra mi trng gy nhim ngun nc. V cc ngun gy nhim tc ng n cht lng nc sng Srepok s c nh gi chi tit trong phn 3: nh gi hin trng mi trng trn lu vc.

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2. Hin trng cht lng nc ngm trn lu vc:

Trn lu vc sng Srepok thc t hin nay do yu cu pht trin kinh t, nhu cu

dng nc khng ngng gia tng, c bit vo ma kh v ang tr thnh p lc ln i

vi qu trnh cng nghip ha, hin i ha ca ca cc a phng trn lu vc Srepok,

trong iu kin dn s gia tng v nh hng mnh m ca bin i kh hu.

Qua cc s liu iu tra cho thy loi khai nc di t trn lu vc Srepok l rt a dng, hu nh c mt cc loi hnh khai nc di t hin c Vit Nam. Loi ging o l loi hnh khai thc nc ngm ch yu trn lu vc cung cp nc sinh hot, ti v chn nui. Hin nay cc vng nng thn tnh k Lk c khong 204.422 ging o cung cp nc sinh hot cho khong 1.028.738 ngi v khong 9.128 ging khoan ng knh nh cung cp cho khong 46.210 ngi; 5 huyn ca tnh k Nng thuc lu vc Srepok (k Mil, C Jut, Krng N, k Glong v k Song) c 4.459 ging khoan v 21.226 ging o cung cp cho khong 150.000 ngi. Vi nhu cu cp nc 60 lt/ngy-ngi th lng nc ngm cung cp cho ngi dn nng thn khong 74.097 m3/ngy. (ngun: hin trng khai thc v s dng ti nguyn nc giai on 2005 -2010 v nh hng s dng n nm 2020 lu vc sng Srepok TT Quy hoch v iu tra ti nguyn nc).

Theo bo co hin trng mi trng tnh k Lk v k Nng cho thy cht lng nc ngm ti tt c cc v tr kho st u b nhim bi hm lng vi sinh vt trong nc cao. Gi tr tng Coliform dao ng trong khong 0-4.600MPN/100ml so vi QCVN 09:2009/BTNMT vt nhiu ln cho php l 3MPN/100ml. Ngun gc nhim c th l do cc cng trnh v sinh, cc cng trnh x l cht thi chn nui, nc thi sinh hot khng qua x l, ch yu theo phng n t thm nn xy ra hin tng thm nc thi lm nhim cc tng nc di t.

- Cht lng nc di t ti tnh k Lk:

Trn a bn tnh k Lk cht lng nc di t c la chn trn cc vng i din cho tnh l cc khu vc huyn Krng Bng (N1), Huyn Ea Soup (N2), Huyn Mrk (N3), huyn Ea Kar (N4), Huyn Lk (N5), Huyn Ea HLeo (N6), Krng Buk (N7), huyn Bun n v Tp. Bun Ma Thut (N8).

biu th c th cho mt s cc thng s nhim nc di t chng ta xem cc th sau:

13

Hnh 12: pH nc di t

Hnh 13:Tng cng nc di t

Hnh 14: hm lng NO2 nc di t

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Hnh 15: hm lng NO3 nc di t

Hnh 16: hm lng Mn & Fe nc di t

Hnh 17: Tng Coliforms nc di t

Ngun: bo co hin trng mi trng tnh k Lk -2010

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Kt qu quan trc cht lng nc di t cho thy:

- pH: tt c cc im quan trc dao ng trong khong 4,9-7,5 so vi Quy chun nc di t QCVN 09:2009/BTNMT hu ht u thp v khng t tiu chun cho php.

- Tng cng: Kt qu quan trc cho thy tng cng dao ng t 5-207 mgCaCO3/l v t QCVN 09:2009/BTNMT, quy nh t 300-500 mgCaCO3/l.

- nhim do kim loi nng: Kt qu phn tch kim loi nng u thp hn gii hn cho php ca QCVN 09:2009/BTNMT.

- nhim vi sinh vt: Kt qu quan trc ti cc khu vc cho thy hu ht cc ging quan trc u b nhim vi sinh vt. Gi tr tng Coliform dao ng trong khong 0-4.600MPN/100ml so vi QCVN 09:2009/BTNMT vt nhiu ln tiu chun cho php.

Cc ch tiu khc nm trong quy chun cho php.

Vo ma ma thng 9 nm 2012 v ma kh thng 3 nm 2013 Vin Quy hoch

thy li tin hnh ly mt s mu nc di t trn a bn cc tnh Ty Nguyn nhm

s b nh gi cht lng nc cp cho sn xut v sinh hot trong c 2 tnh k Lk

v k Nng.

Ti tnh k Lk ly 15 mu nc di t gm:

Bng 2: Cc v tr ly mu nc di t tnh k Lk

TT Tn v tr kho st Ta

X Y

Mu 1 Nc ging cp SH thn Ha Nam x E Nhon TP Bun M Thut-L 1405420 0181035

Mu 2 Nc ging G: H Lan x Tn Ha huyn Bun n L 1414312 0816480

Mu 3 Nc ngm cp SH G:Nguyn Vn Thng x Ha Hip huyn C Kuin

L 1386605 0194391

Mu 4 Nc ging G: Cao Vn Hi x C Su huyn C M'Gav L 1391272 0231926

Mu 5 Nc ging G: Phm Loan x Ea Leo huyn Ea H'Leo L 1404455 0235854

Mu 6 Nc ngm G: Y Men x Xun Ph huyn Ea Kar - L 1338626 0211229

Mu 7 Nc ging G: Nguyn Th Vn TT Ea Sp huyn Ea Sp L 1455227 0806216

Mu 8 Nc ngm cp SH G: Phm Hng x Bng ADrinh huyn Krng Ana L 1380835 0176408

Mu 9 Nc ngm cp SH G: H Lan x Yang Reh huyn Krng Bng L 1381584 0201017

Mu 10 Nc ngm cp SH G: Nguyn Hoa x Ea Blng huyn Krng Bk - L 1429535 0203273

Mu 11 Nc ngm G: Nguyn Th Tuyt x Tm Giang - Krng Nng-L 1436254 0217700

Mu 12 Nc ngm G: Nguyn Phc x Ea Kly huyn Krng Pk L 1407695 0215660

Mu 13 Nc ngm cp G: Nguyn Xun x Yang Tao huyn Lk L 1394628 0189040

Mu 14 Nc ngm cp G: Nguyn Th Hi x Ea Pil huyn M' rk L 1406820 0256762

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Kt qu kho st o c v phn tch cho thy:

- Vo ma ma gi tr pH dao ng trong khong 4,3 7,4. Trn tng 15 ging kho

st th c 5 ging ti cc huyn th nh thnh ph Bun Ma Thut, huyn Ea H'Leo,

Krng Bng, Krng Nng, Krng Pk c gi tr pH thp, khng tha mn gii hn

ca QCVN 09: 2008. Vo ma kh, cht lng nc ngm trn a bn tnh k

Lk khng c s thay i nhiu so vi ma ma. Mc nc trong cc ging gim,

ngun nc ngm b nhim bi hm lng cc cht hu c trong nc kh cao.

Gi tr pH ti hu ht cc ging khng tha mn gii hn ca quy chun. Ti 15

ging kho st ch c 5 ging c gi tr tha mn gii hn ca quy chun. Hm

lng Fe tng, Cl-, Ca2+, Mg2+ trong nc thp, tha mn gii hn ca quy chun.

- Hm lng cc cht nhim nhm N thp, hm lng NH4+, NO2-, NO3- u nm

trong gii hn ca quy chun.

- Hm lng cc cht hu c trong nc cao, ti tt c 15 ging kho st trn a bn

tnh th hm lng COD u vt qu gii hn ca QCVN 09: 2008. Hm lng vi

sinh trong nc ngm tnh k Lk cao, ti 15 ging kho st ch c 3/15 ging c

hm lng Coliform nm trong gii hn ca QCVN 09: 2008, s ging cn li u

c gi tr Coliform vt qu gii hn ca QCVN 09: 2008.

Theo kt qu phn tch cho thy ngun nc b nhim do hm lng vi sinh trong

nc kh cao. c bit ti khu du lch Bn n huyn Bun n ngun nc ngm vo

ma kh b nhim nng, ngi dn phi mua nc sch dng. Ngun nc ngm t cc

ging o bm ln khng th s dng do mi hi do nc b nhim nhiu st, nh hng

rt ln n i sng ngi dn. Cc ch tiu cht lng nc khc nm trong quy chun

cho php.

Kt qu phn tch xem bng 3.

Mu 15 Nc ngm cp G: H Th Lung th x Bun H - Krng Bk L 1423515 0202515

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Bng 3: Kt qu phn tch nc di t trn a bn tnh k Lk

Thng s n v

Kt qu QCVN 09:2009 Mu 1 Mu 2 Mu 3 Mu 4 Mu 5

Ma Kh Ma Kh Ma Kh Ma Kh Ma Kh

pH mg/l 5.2 5.99 5.5 6.12 7 4.95 5.7 4.17 4.3 5.82 5,5-8,5

TSS mg/l 28 26 14 32 8 4 10 7 12 15 1500

Cl- mg/l 15.8 81.65 17.9 21.3 20.1 35.5 10.5 92.3 15.6 35.5 250

cng ton phn mg/l 188 407 126 476 162 292 180 264 125 305 500

NH4+ mg/l 0.055 0.033 0.056 0.026 0.048 0.037 0.058 0.056 0.062 0.112 0,1

NO2- mg/l 0.012 0.002 0.009 0.002 0.007 0.005 0.004 0.028 0.003 0.029 1,0

NO3- mg/l 0.069 0.029 0.066 0.041 0.064 0.053 0.053 0.07 0.048 0.03 15

SO42- mg/l 26.4 42.3 16.5 49.2 12.2 14.6 10.6 12 14 18 400

COD mg/l 7.6 8.3 7.2 19.7 8.7 9.1 6.8 7.4 5.9 6.9 4

Coliform MPN/100ml 6 3 6 6 5 2 6 2 3 1 3

Thng s n v

Kt qu QCVN

09:2009 Mu 6 Mu 7 Mu 8 Mu 9 Mu 10


pH mg/l 5.7 4.73 7.4 6.2 5.37 5.1 5 5.19 5.8 3.28 5,5-8,5

TSS mg/l 21 11 28 32 44 8 14 16 12 6 1500

Cl- mg/l 17.6 28.4 15.9 14.2 16.2 56.8 7.1 74.55 21.6 63.9 250

cng ton phn mg/l 163 372 210 412 246 296 90 301 216 95 500

NH4+ mg/l 0.06 0.028 0.056 0.041 0.069 0.057 0.062 0.076 0.064 0.096 0,1

NO2- mg/l 0.004 0.002 0.001 0.19 0.003 0.016 0.002 0.007 0.002 0.002 1,0

NO3- mg/l 0.052 0.221 0.033 0.048 0.034 0.03 0.03 0.029 0.059 0.033 15

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Thng s n v

Kt qu QCVN

09:2009 Mu 6 Mu 7 Mu 8 Mu 9 Mu 10


SO42- mg/l 12.6 21 30.6 40.5 38.6 32 10.4 30.2 26.2 20.5 400

COD mg/l 6.4 7.1 8.5 9.1 7.05 7.4 6.2 6.8 5.4 7.3 4

Coliform MPN/100ml 4 2 2 3 7 3 2 3 6 2 3

Thng s n v

Kt qu QCVN

09:2009 Mu 11 Mu 12 Mu 13 Mu 14 Mu 15


pH mg/l 5.4 5.72 5.3 5.44 6.8 3.6 5.7 5.22 6.7 4.61 5,5-8,5

TSS mg/l 20 35 11 20 14 8 18 12 12 78 1500

Cl- mg/l 19.76 35.5 8.7 71 5.9 21.5 16.7 35.5 13.9 17.75 250

cng ton phn mg/l 205 325 177 327 105 176 22.6 165 112 121 500

NH4+ mg/l 0.056 0.023 0.07 0.02 0.058 0.1 0.062 0.073 0.063 0.029 0,1

NO2- mg/l 0.001 0.004 0.002 0.003 0.001 0.005 0.001 0.025 0.002 0.003 1,0

NO3- mg/l 0.03 0.028 0.032 0.033 0.033 0.045 0.03 0.029 0.034 0.025 15

SO42- mg/l 32 34.7 12 31 14.6 20.2 21.6 18.2 18.4 35.4 400

COD mg/l 6.76 9.7 4.9 5.9 5.8 7.2 6.12 8.5 7.7 8.3 4

Coliform MPN/100ml 6 4 8 3 6 4 3 3 2 1 3

Ngun: Quy hoch tng th vng Ty Nguyn Vin Quy hoch thy li - 2013

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Trong bo co: nh gi hin trng cht lng nc di t, xut bin php khc phc v bo v ti nguyn nc di t phc v nc sinh hot trn a bn tnh k Lk ca on Quy hoch v iu tra Ti nguyn nc 704. Thng qua kt qu phn tch ca 853 mu nc c th nhn xt cht lng nc di t nh sau:

V tnh cht vt l:

- Nc di t trn a bn tnh k Lk hu ht khng mu, khng mi, v nht.

Nhit ca nc thay i 25 n 260C, thng gp 260C. Tuy nhin, mt s ni nc b

nhim st, thng c mi tanh.

- pH ca nc di t thay i t 5,52 n 10,35 trung bnh 7,3. Trong tng s

mu phn tch ch c 7 mu (chim 1,42%) vt gi tr gii hn (GTGH), gi tr ln nht

vt khng ng k so vi GTGH (vt 1,2 ln).

- cng:

Kt qu phn tch mu nc cho thy cng ca nc di t thay i t 7,5

n 450,07 mgCaCO3/l, trung bnh 101,0 mgCaCO3/l. Nh vy, nc di t tnh k

Lk thuc nc rt mm n mm. Gi tr cao nht cng ch t ti 450,07 mgCaCO3/l

(nc ging khoan gia nh b Nguyn Th Lin, thn 6, x Ea Wer, Bun n), vn thp

hn so vi GTGH (Gi tr gii hn: 500 mgCaCO3/l).

Tuy nhin, theo tiu chun v sinh nc sch ban hnh theo Quyt nh s

09/2005/Q-BYT ca B Y t th GTGH cho php ca cng l 350 mg/l. Nu theo

Tiu chun ny th c mt s mu nc c cng vt GTGH, chng phn b cc x

Krng Na, Ea Wer v th trn Bun n ca huyn Bun n. Nh vy, nc di t

vng Bun n v Ea Sp trong trm tch Jura c cng cao hn so vi tng cha nc

khc. Nguyn nhn cng ca nc cao l do cc lp ct kt vi cha trong trm tch

Jura b thy phn, lm tng hm lng bicarbonat v calci trong nc.

- Cht rn tng s (TDS):

Cht rn tng s ca nc di t (tng khong ha ca nc) thay i t 20,0

mg/l n 840,0 mg/l, trung bnh 165,3 mg/l. Trong s mu nc phn tch cho thy

cha c mu no c tng khong ha vt qu 1.000 mg/l. Nc di t tnh k lk

thuc loi siu nht n nht, ch yu l nc siu nht.

- Hm lng Amoni (NH4+):

Hm lng Amoni thay i t khng pht hin n 0,3 mg/l, trung bnh 0,032 mg/l.

Trong s 494 mu phn tch c 46 mu hm lng Amoni vt GTGH chim 9,3%. Mt

khc qua kt qu phn tch hm lng Amoni theo thi gian ti l khoan quan trc LKC8b

Phc An, Krng Pach trong tng cha nc bazan, cho thy chng tng kh nhanh.

20

Nm 2002 khng pht hin thy Amoni trong nc, song n nm 2009 tng ln 0,11 mg/l

(xem hnh 18).

Hnh 18: th dao ng hm

lng Amoni (NH4+) trong nc

di t ti l khoan quan trc

C8b. 0

0.02

0.04

0.06

0.08

0.1

0.12

3/2002 3//2003 3/2007 3/2008 3/2009

Thi gian

Hm

l

ng N

H4, m

g/l

Ngun: n quan trc quc gia ti nguyn mi trng nc di t vng Ty

Nguyn

Kt qu phn tch hm lng Amoni trong nc di t trm tch Jura theo thi

gian ti cc l khoan quan trc LK23T (Krng Na Bun n) v LK28T (Ea Sp) cho

thy chng tng kh nhanh (xem hnh 18). Nm 2001 khng pht hin thy Amoni trong

nc, song n nm 2008 tng ln 0,05 mg/l (LK23T) v 0,09 mg/l (LK28T).

Hnh 19: th dao ng hm lng Amoni (NH4+) trong nc di t ti

cc l khoan quan trc LK23T v LK28T.

LK23T (Bun n)

LK28T (Ea Sp)

Ngun: n quan trc quc gia ti nguyn mi trng nc di t vng Ty Nguyn

Nh vy, nc di t tnh k Lk c mc nhim Amni tng nhanh theo

thi gian v khng gian.

- Hm lng Nitrit (NO2-):

Hm lng Nitrit trong nc di t thay i t khng pht hin thy n 3,02

mg/l, trung bnh 0,04 mg/l, thp hn nhiu so vi GTGH (1,0 mg/l). Trong s 494 mu

phn tch c 3 mu c hm lng Nitrit vt GTGH cho php t 1,1 ln n 3,02 ln, l

21

cc mu ti ging B152 Bun n (1,2 mg/l), ti s 55 Hng Vng - th trn Ea Sup

(3,02 mg/l) v l khoan quan trc quc gia LK28T (1,11 mg/l).

Nc di t khu vc l khoan LK28T trong trm tch Jura c mc nhim

Nitrit tng nhanh theo thi gian. Kt qu phn tch nc nm 2003 c hm lng Nitrat l

0,01 mg/l, nm 2007 l 0,08 mg/l v n nm 2008 tng ln 1,11 mg/l, lc ny nc b

nhim Nitrit (xem hnh 20).

Hnh 20: th dao ng hm lng Nitrit trong nc di t tng theo thi gian ti l khoan LK28T. 0.000

0.200

0.400

0.600

0.800

1.000

1.200

9/ 2002 9/ 2003 9/ 2007 9/ 2008

Thi gian

H

m l

ng

NO

2,

mg

/l

Ngun: n quan trc quc gia ti nguyn mi trng nc di t vng Ty Nguyn

- Hm lng Nitrat (NO3-):

Nitrat trong nc di t thay i t khng pht hin n 184,4 mg/l, gi tr trung

bnh 8,0 mg/l. Trong s 494 mu phn tch c ti 45 mu hm lng Nitrat vt GTGH

(chim 9,1%). Trong s 45 mu vt GTGH, chng phn b: C Mgar, Krng Pach, Ea

Kar, thnh ph Bun Ma Thut, C Kuin, Bun n. Hm lng Nitrat cao trong nc

thng gp Ea Kar, c ni vt ti 12,2 ln so vi GTGH cho php. C th, ti khi ph

3, th trn Ea Knp (87,1 mg/l); cm cng nghip Ea ar (21,98 mg/l); t An C, th trn

Ea Kar (184,4 mg/l),

Cng nh thng s Amoni, s nhim Nitrat nc di t c s tng nhanh theo

thi gian. C th, vi 277 mu phn tch trc nm 2005 th ch c 12 (chim 4,3%) mu

hm lng Nitrat vt GTGH (vt cao nht 2,5 ln), trong khi vi 154 mu phn tch

ca ti th c ti 24 mu (chim 15,6%) hm lng Nitrat vt GTGH (vt cao nht

12,2 ln - t An C, TT Ea Kar).

Kt qu mu phn tch Nitrat theo thi gian ti l khoan quan trc LKC8a Phc

An, Krng Pach trong tng cha nc bazan, cho thy ma kh nm 1998 Nitrat 9,3 mg/l

v n ma kh nm 2009 n tng ln ti 70,8 mg/l (xem hnh 21).

22

Hnh 21: th dao ng hm lng Nitrat trong nc di t theo thi gian ti l khoan quan trc C8a Phc An

0

20

40

60

80

3/1998 3/1999 3/2001 3/2003 3/2007 3/2009

Thi gian, nm

Hm

l

ng N

O3, m

g/l


Nguyn

Kt qu mu phn tch Nitrat theo thi gian ti l khoan quan trc LK27T Ch

Mlanh huyn Ea Sup, cho thy ma ma nm 2001, khng pht hin thy Nitrat v n

ma ma nm 2008 n tng ln 0,12 mg/l (xem hnh 22).

Hnh 22: th bin i hm lng Nitrit

trong nc di t theo thi gian ti l

khoan LK27T 0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

9/2001 9/2002 9/2003 9/2007 9/2008

Thi gian

Hm

l

n

g N

O3

, m

g/l


Nguyn

Nh vy, nc di t tnh k Lk c mc nhim Nitrat tng nhanh theo

thi gian v khng gian

- Hm lng Clorua (Cl-):

Clorua c hm lng thay i t 0,53 n 186,13 mg/l, gi tr trung bnh khong

26,5 mg/l. Nh vy, trong s 494 mu phn tch khng c mu no c hm lng

Clorua vt qu GTGH cho php, gi tr ln nht l 186,13 mg/l ch bng hn na GTGH

cho php (GTGH: 250 mg/l).

- Hm lng Sulfat (SO42-):

Hm lng Sulfat trong nc di t thng nh, thay i t khng pht hin thy

n 196,84 mg/l, thng gp < 2,0 mg/l, mh hn nhiu ln so vi tiu chun cho php

(400 mg/l). Tc l nc di t tnh k Lk hon ton cha c du hiu nhim Sulfat.

- Hm lng st tng cng (Fe2++Fe3+): Tng hm lng ion st bin i t khng

pht hin n 8,18 mg/l, thng gp nh hn 0,5 mg/l.

23

Trong s 494 mu phn tch ch c 8 mu vt khng nhiu so vi GTGH v tiu

chun cht lng nc di t.

Cc mu vt c ly ti LK17 x Tn Ha, Bun n (6,21 mg/l); ging o

715-H n Bun n (5,55 mg/l), Nh my thp ng Nam tp. Bun Ma Thut

(8,18 mg/l) v Ging B254 Bun n: 5,13 mg/l).

Tuy nhin, nu theo Tiu chun nc sch ca B Y t (Quyt nh s

09/2005/Q-BYT) th nc c hm lng tng st (Fe2++Fe3+) > 0,5 mg/l, khi s dng

cho n ung sinh hot th cn phi x l. Nu tnh theo tiu chun ca B Y t, th vi 494

mu phn tch c 74 mu (chim 13,6%) c hm lng st vt qu 0,5 mg/l. Nc

di t c hm lng tng st >0,5 mg/l thng phn b Bun n, Ea Sp, Krng

Ana, pha ty thnh ph Bun Ma Thut, Krng Buk, Ea Kar, C Mgar v huyn Lk.

V hm lng cc hp cht c hi, kim loi nng trong nc di t tnh k

Lk, theo kt qu phn tch mu cho thy hu ht chng u c gi tr thp, nm trong gii

hn cho php theo tiu chun hin hnh. C th nh sau:

- Hm lng Florua (F):

Qua kt qu phn tch ca 177 mu nc cho thy hm lng Florua trong nc

di t thay i t 0,001 n 1,927 mg/l, trung bnh 0,122 mg/l, thp hn nhiu so vi

tiu chun cho php. Trong s mu phn tch c 2 mu (1,1%) c hm lng Florua vt

GTGH cho php t 1,7 n 1,9 ln. Mu th nht ly ti ging gia nh ng Nguyn Hu,

55 Hng Vng, th trn Ea Sup c hm lng Florua 1,927 mg/l; mu th hai ly ging

nh ng Thin, Bun Bng, x k Ling, huyn Lk, c hm lng Florua 1,78 mg/l.

Nc di t khi b nhim Florua (F > 1,0 mg/l) c th gy ra cc bnh v rng

nh m rng, mc rng, cht rng (dental Floruaosis), cn khi hm lng Florua vt qu

5 mg/l th thng xy ra cc bnh Floruasis khung xng nh x cng khp, to khp,

lit chi, ....

- Hm lng Xianua (CN-):

Vi kt qu phn tch ca 177 mu nc di t cho thy hm lng Xianua thay

i t 0,0001 n 0,006 mg/l, trung bnh khong 0,002 mg/l, thp hn nhiu so vi tiu

chun cho php (GTGH: 0,01 mg/l).

- Hm lng Phenol:

Hm lng Phenol trong nc di t thay i t 0,0001 n 0,0019 mg/l, trung

bnh 0,0006 mg/l. Trong tng s 177 mu phn tch c 5 mu (chim 2,8%) vt GTGH.

Kt qu phn tch ca 5 mu c hm lng Phenol vt qu GTGH cho php thuc n

iu tra ngun nc di t mt s vng trng im tnh k Lk: 3 mu x Dli

Yang Ea Hleo (0,0003 - 0,0019 mg/l), mt mu x C Png Krng Buk (0,0011

24

mg/l), mt mu x Ea Hng CMgar (0,0019 mg/l). Tuy nhin, hm lng ca

chng ch vt cht t so vi GTGH cho php (0,001 mg/l).

Khi s dng nc c hm lng Phenol vt qu GTGH cho n ung, v lu di c

th gy vim gan, thn,

- Hm lng Asen (As):

Qua kt qu phn tch ca 225 mu nc (trong c 48 mu thu thp c ly ti

cc trm cp nc tp trung) cho thy hm lng Asen trong nc di t tnh k Lk

thay i t

25

Hm lng Crm trong nc di t thay i t 0,001 n 0,0052 mg/l, trung bnh

0,002 mg/l, thp hn nhiu so vi gi tr gii hn (GTGH: 0,05 mg/l).

- Hm lng ng (Cu):

Kt qu phn tch ca 177 mu nc di t cho thy hm lng ng thay i t

0,0001 n 0,009 mg/l, trung bnh 0,001 mg/l, thp hn nhiu so vi gi tr cho php

(GTGH: 1,0 mg/l).

- Hm lng Km (Zn):

Hm lng Km qua kt qu phn tch ca 177 mu nc cho thy chng thay i

t 0,001 n 0,783 mg/l, trung bnh 0,045 mg/l, thp hn nhiu so vi gi tr gii hn cho

php (GTGH: 3,0 mg/l).

- Hm lng Mangan (Mn):

Qua kt qu phn tch mu nc cho thy hm lng Mangan trong nc di t

thay i t 0,008 n 4,452 mg/l, trung bnh 0,191. Trong s 177 mu phn tch c 12 mu

(chim 6,7%) vt GTGH t t 1,2 n 8,9 ln. Cc mu nc c hm lng Mangan

vt GTGH cho php phn b nh sau:

- Huyn Bun n: ti l khoan LK11 - Bun n (0,586 mg/l); ging khoan

UBND x EaHuar (0,604 mg/l); ging khoan gia nh ng V Vn Cn, thn Ea Duat, th

trn Bun n (0,898 mg/l); trm cp nc tp trung x Krng Na (0,835 mg/l); l khoan

LK14, th trn Bun n (0,645 mg/l); l khoan LK21 x Krng Na (0,579 mg/l).

- Huyn Ea Sup c 2 mu: ging o gia nh ng inh Vn Hi, thn 3, x Ea Jli

(0,617 mg/l) v ging khoan gia nh ng inh Vn Long, thn 10, x Ea Rc (4,452

mg/l).

- Huyn Lk c 2 mu vt: ging khoan ng Nguyn Vn Thnh, thn on Kt

2, x Bun Trit (1,756 mg/l) v ging khoan gia nh b V Th Su, thn 1, x ry Sap

(0,636 mg/l).

Ngoi ra c mt mu thn 12, Ea Knut, huyn Ea Kar (0,623 mg/l) v ti thn 1,

Bun Trp, huyn Krng Ana (0,578 mg/l).

Khi s dng nc c hm lng Mangan vt qu GTGH cho php cho n ung c

th gy suy nhc thn kinh, gim tr nh, ri lon ni tit, chy mu cam, cc bnh v

phi.

- Hm lng Thy ngn (Hg):

26

Kt qu phn tch 177 mu nc cho thy hm lng Thy ngn trong nc di

t tnh k Lk thay i t 180.000 MPN/100ml, vt nhiu ln so vi GTGH cho php (Coliform: 3

MPN/100ml, tng E.coli: khng c). Trong tng s 84 mu phn tch c ti 51 mu vt

v E.Coli (chim 60,7%) v 35 mu vt v Coliform (chim 41,7%). Nguyn nhn nc

di t tnh k Lk b nhim vi sinh l do iu kin v sinh mt s ging dn dng

27

cn km, mt khc pha trn cc tng cha nc l v phong ha bazan c kh nng thm

nc, nn mc t bo v ca tng cha nc khng cao.

Theo bo co trn th mt iu cng ng lu l nhim ngun nc c th cn

gy ra bi di sn ca chin tranh. Theo ti liu nghin cu cng b gn y, trong thi k

1961 - 4/1975, qun M v ng minh s dng gn 100.000 tn cht c ha hc, trong

c 57.000 tn l cht da cam/ixin trn din tch khong 3 triu ha Vit Nam, trong

c tnh k Lk. Nh bit, chu k bn hy ca ixin trong mi trng c th t 3 -

12 nm. Hn na, phn ln b phn hu, mt phn c ra tri do nc ma lm cho

phn ln hm lng cht cht c trong mi trng gim. Theo bo co ti ti nghin

cu, th tnh k Lk (c) vi tng din tch l 1.980.000 ha s cn cha khng qu

1.030g ioxin.

Nu gi s ton b lng cht c da cam/ixin ny c ra tri trong mt ma

ma v ton b vo khu vc sng Srpok (vi lu lng trung bnh nm l 8,0 t

m3/nm) th hm lng da cam/ixin trong nc sng Xrpok s 0,127 g/l (hay 0,127

ppt), di xa mc cho php pht hin ca cc k thut hin i (1 ppt), ngha l di

mc gy tc hi n h sinh thi nc v con ngi. Tnh ton trn da trn gi thuyt l

ton b lng ixin cn li c a vo lu vc sng Srepok trong mt nm. Trn thc

t lng ixin tn lu b tht thot nhiu v ri rc ch khng th dn ton b vo

thng ngun sng Srpok. V vy, hm lng thc t ca ixin trong nc sng Srpok

c th thp hn tnh ton.

Di y l bng tng hp kt qu phn tch mu nc di t tnh k Lk

Bng 4: Tng hp kt qu phn tch mu nc di t tnh k Lk

TT Thng s

n v

Gi tr gii hn

S mu

phn

tch

Gi tr S mu t tiu

chun v (khng

t)

Ln nht

Nh nht

Trung

bnh

1 pH 5,5-8,5 494 10,35 5,52 7,3 283 (7)

2 cng mg/l 500 494 450,07 7,5 101,0 285 (0)

3 Cht rn tng s mg/l 1.500 494 840,0 20,0 165,3 285 (0)

4 Amoni (tnh theo N) mg/l 0,1 494 0,3 0,0 0,032 263 (46)

5 Nitrit NO2

- (tnh theo

N) mg/l 1,0 494 3,02 0,0 0,04 285 (3)

6 Nitrat NO3

- (tnh

theo N) mg/l 15,0 494 184,4 0,0 8,0 264 (45)

28


Nguyn

So snh vi s liu phn tch t nm 2006 n nm 2009 ca S Ti nguyn v Mi

trng tnh k Lk, s liu quan trc ca on Quy hoch v iu tra Ti nguyn nc

704 t nm 2002 n nm 2009 v s liu ca vin Quy hoch Thy li trong 2 nm 2012

-2013 c th s b nh gi:

- Gi tr pH ti nhiu v tr kho st nc di t u thp khng nm trong quy

chun cho php, so snh vi gi tr pH trong nm 2012 v 2013 ti cc v tr kho

st do vin Quy hoch thy li thc hin c xu hng gim i.

- Tng cng ti cc v tr kho st t nm 2006 n 2013 u thp nm trong gi

tr cho php.

- Nhm Amoni trong nm 2001 thp, hu nh cc s liu kho st u nm trong

quy chun cho php, tuy nhin n nm 2008 tng ln n 0,05 mg/l (LK23T) v

0,09 mg/l (LK28T).

7 Clorua (Cl-) mg/l 250 494 186,13 0,53 26,5 285 (0)

8 Sulfat (SO42-) mg/l 400 494 196,84 0,0 5,44 285 (0)

9 St mg/l 5,0 544 8,18 0,0 0,43 309 (8)

10 Florua (F-) mg/l 1,0 177 1,927 0,001 0,122 101 (2)

11 Xianua (CN-) mg/l 0,01 177 0,006 0,0001 0,0020 89 (0)

12 Phenol mg/l 0,001 177 0,0019 0,0001 0,0006 99 (5)

13 Asen (As) mg/l 0,05 225 0,041

29

- Hm lng COD c xu hng tng cao ti cc v tr kho st trong nm 2012 -

2013, ti tt c cc v tr kho st u khng quy chun cht lng nc ngm

09:2008.

- Hm lng coliform c din bin phc tp v hu ht cc cc im kho st u

vt quy chun cho php nhiu ln, cc bit c im hm lng Coliform vt quy

chun nc ngm n 35.000 MPN/100ml. Trong tng s 84 mu phn tch c ti

51 mu vt v E.Coli (chim 60,7%) v 35 mu vt v Coliform (chim 41,7%)

- Nhm kim loi nng nhn chung thp, nm trong quy chun cho php.

- Cht lng nc di t trn a bn tnh k Nng:

Trn a bn tnh k Nng vo thng 11 nm 2011, trung tm Quan trc Ti nguyn v Mi trng tnh tin hnh ly mu ti 20 v tr sau:

Bng 5 : v tr ly mu nc di t tnh k Nng

K hiu V tr ly mu

NN01 H V c T, thn 2 x k Buk So

NN02 Bu in huyn Tuy c

NN03 Tim tp ha Tun Hng, KP1, TT Kin c

NN04 Shop ng Khoa ng ba Nhn C

NN05 H Trn Ngc Sn phng Ngha Tn gn thy in k Nng

NN06 Bn xe Gia Ngha

NN07 Nh ngh T Uyn (gn cu k Nng)

NN08 TT k Mm

NN09 X c Xuyn

NN10 Cty pht trin h tng KCN Tm Thng

NN11 Cty g Hng Thnh

NN12 Nh ngh Thy Nguyn (ng t TT Ea Tlinh)

NN13 Qun caf cu 14

NN14 H dn thn c Trung, x c Mnh

NN15 H V nh Ph, khi 8 th trn k Mil

NN16 Thn Thun Hnh Thun An

NN17 TT c An

NN18 H Phng Th Tut, thn 9 x Nm N Jang

NN19 Bn xe Qung Kh

NN20 H dn h Qung Kh

30

Thng qua kt qu phn tch cho thy:

- Gi tr pH dao ng trong khon t 6,7 n 7,5 nm trong gi tr gii hn cho php trong QCVN 09:2008

- cng trong nc di t dao ng t 27 mg/l n 133 mg/l nm trong gi tr gii hn cho php.

- Hm lng COD thp nm trong gi tr gii hn cho php.

- Hm lng NH4+ thp dao ng t 0.01 mg/l n 0.045 mg/l, tuy nhin mu s NN14 c hm lng NH4+ cao, c gi tr l 0.36 mg/l vt quy chun cho php 3.6 ln.

- Nhm NO2- v NO3- thp nm trong gi tr quy chun cho php.

- Hm lng kim loi nng thp nm trong quy chun cho php, trong hm lng Asen trong cc muphn tch u khng thy xut hin.

Kt qu phn tch xem bng 5

31

Bng 6: Kt qu phn tch cht lng nc ngm tnh k Nng

TT Thng s n v V tr QCVN

09:2008/BTNMT NN01 NN02 NN03 NN04 NN05 NN06 NN07

1 pH - 7,3 7,5 7,1 7,4 6,9 7,1 7,5 5,5 8,5

2 cng (tnh theo CaCO3)

mg/l 78 133 95 41 54 55 27

500

3 Cht rn tng s mg/l 57,2 62,4 53,3 105,7 82,5 69,7 71,6 1.500

4 COD (KMnO4) mg/l 1 KPH 2 1 2 1 KPH 4

5 Amni(tnh theo N) mg/l 0,015 0,037 0,028 0,023 0,031 0,043 0,011 0,1

6 Nitrit (NO2-) (tnh theo

N) mg/l

0,006 0,021 0,017 0,014 0,025 0,015 0,007 1,0

7 Nitrat (NO3-) (tnh theo

N)

mg/l 1,42 0,64 1,19 0,72 1,05 2,25 2,71

15

8 Sulfat (SO42-) mg/l 4,93 6,72 2,64 4,92 1,58 2,74 4,01 400

9 Asen (As) mg/l KPH KPH KPH KPH KPH KPH KPH 0,05

10 Km (Zn) mg/l 0,39 0,16 0,5 0,08 0,25 0,08 0,13 3,0

11 Crom VI (Cr6+) mg/l KPH KPH KPH KPH KPH KPH KPH 0,05

12 ng (Cu) mg/l KPH 0,014 0,106 KPH 0,073 0,092 0,05 1,0

13 St (Fe) mg/l 0,45 0,53 0,62 0,67 0,12 0,15 0,11 5

32

TT Thng s n v V tr QCVN

09:2008/BTNMT NN08 NN09 NN10 NN11 NN12 NN13 NN14

1 pH - 6,8 7,5 7,3 6,9 7,0 7,0 7,2 5,5 8,5


mg/l 28 37 45 39 64 53 40

500

3 Cht rn tng s mg/l 45,8 76,3 58,2 80,7 63,4 68,6 55,4 1.500

4 COD (KMnO4) mg/l KPH 6 1 2 KPH KPH KPH 4

5 Amni(tnh theo N) mg/l 0,013 0,017 0,031 0,027 0,012 0,02 0,36 0,1


N) mg/l

0,005 0,01 0,015 0,011 0,008 0,012 0,022 1,0


N)

mg/l 0,35 1,82 3,16 0,58 2,3 1,6 1,79

15

8 Sulfat (SO42-) mg/l 2,07 5,23 1,47 3,82 2,93 2,48 1,73 400

9 Asen (As) mg/l KPH KPH KPH KPH KPH KPH KPH 0,05

10 Km (Zn) mg/l 0,51 0,47 0,71 0,06 1,08 0,92 3,0

11 Crom VI (Cr6+) mg/l KPH KPH KPH KPH KPH KPH KPH 0,05

12 ng (Cu) mg/l 0,02 0,004 KPH 0,007 0,003 KPH 0,01 1,0

13 St (Fe) mg/l 1,24 0,57 1,4 1,71 0,64 2,05 0,83 5

33

TT Thng s n v V tr

QCVN

09:2008/BTNMT

NN15 NN16 NN17 NN18 NN19 NN20

1 pH - 6,7 7,0 7,1 6,8 6,8 6,9 5,5 8,5


mg/l 47 62 38 52 33 40

500

3 Cht rn tng s mg/l 52,4 87,3 48,1 72,5 69,3 51,6 1.500

4 COD (KMnO4) mg/l 2 KPH KPH 1 KPH 1 4

5 Amni(tnh theo N) mg/l 0,01 0,045 0,031 0,018 0,038 0,029 0,1


N) mg/l

0,007 0,027 0,018 0,012 0,019 0,017 1,0


N)

mg/l 0,57 1,3 0,65 1,14 1,03 1,27

15

8 Sulfat (SO42-) mg/l 15,7 8,2 10,5 21,1 25,3 18,5 400

9 Asen (As) mg/l KPH KPH KPH KPH KPH KPH 0,05

10 Km (Zn) mg/l 0,34 KPH KPH 0,05 0,17 KPH 3,0

11 Crom VI (Cr6+) mg/l KPH KPH KPH KPH KPH KPH 0,05

12 ng (Cu) mg/l 0,002 0,033 0,01 0,025 KPH 0,01 1,0

13 St (Fe) mg/l 0,73 1,18 0,58 1,13 2,16 1,39 5

Ngun: Trung tm Quan trc Ti nguyn v Mi trng tnh k Nng -2011

34

Trong nm 2012 v 2013 vin Quy hoch Thy li tin hnh ly 8 mu nc di t gm:

Bng 7: cc v tr ly mu ti tnh k Nng

Kt qu phn tch cho thy:

- Ti 8 v tr kho st trn a bn tnh trong ma ma th c ti 5 ging ti cc huyn

th nh th x Gia Ngha, huyn k Glong, k Song, Krng N, Tuy c c pH

thp dao ng t 3.57 n 6.44 khng nm trong gii hn ca QCVN 09: 2008.

- Hm lng Fe tng, Cl-, Ca2+, Mg2+, SO42-,...thp, nm trong gii hn ca quy chun.

- Hm lng cc cht nhim nhm N thp, hm lng NH4+, NO2-, NO3- u nm

trong gii hn ca quy chun.

- Hm lng cc cht hu c trong nc ngm tnh k Nng cao, hm lng COD

trong cc ging kho st u vt qu gii hn ca QCVN 08: 2008. Hm lng vi

khun trong nc thp, ti 8 ging kho st ti cc huyn th th c 3 ging c gi tr

hm lng Coliform vt qu gii hn ca QCVN 09: 2008 nh huyn k Glong,

k R'Lp, Krng N.

Vo ma kh, cc ging kho st u c hm lng cc cht hu c kh cao, hm

lng COD ti 8 ging kho st u vt qu gii hn ca quy chun. Ging ti cc huyn

nh C Jt, k Glong, Tuy c th hm lng COD cn vt qu 2 ln gi tr gii hn.

Gi tr pH ti cc ging thp, ch c 2 ging c gi tr pH tha mn gii hn ca quy chun.

Hm lng Coliform ti C Jt, k Glong c gi tr kh cao, vt gii hn quy chun nc

ngm. Di y l kt qu phn tch nc di t trn a bn tnh k Nng.

TT V tr ly mu Ta

X Y

Mu 1 Nc ngm Qun cm Thy Hng x Qung Thnh th x Gia Ngha N 1333939 0791843

Mu 2 Nc ngm G: inh T x Tn Thng huyn C Jt N 1411005 0817833

Mu 3 Nc ngm cp SH G: Nguyn Th Vinh th trn k Glong N 1338764 0806291

Mu 4 Nc ngm cp SH x k Gla huyn k Milk N 1392928 0813051

Mu 5 Nc ngm G: Nguyn Thy Trang x Thun Hnh huyn k Song N 1363488 0779034

Mu 6 Nc ngm cp SH G: Minh Nguyt x Qung Tn-k R'Lp-N 1388842 0878183

Mu 7 Nc ngm cp SH G: Cao Th Vn x k So - Krng N - N 1365776 0810697

Mu 8 Nc ngm cp SH ti cy xng Petrolimex k Buk So huyn Tuy c-N 1342450 0768336

35

Bng 8: Kt qu phn tch nc di t trn a bn tnh k Nng

Thng s n v

Kt qu QCVN

09:2009 Mu 1 Mu 2 Mu 3 Mu 4

Ma Kh Ma Kh Ma Kh Ma Kh

pH mg/l 3.8 4 6.1 6.44 4.3 3.72 5.7 4.8 5,5-8,5

TSS mg/l 4 5 14 25 8 9 24 10 1500

Cl- mg/l 5.7 39.05 21.5 35.5 6.3 53.25 24.5 28.4 250

cng ton phn mg/l 142 142 208 297 88 206 182 275 500

NH4+ mg/l 0.069 0.035 0.07 0.033 0.066 0.043 0.061 0.108 0,1

NO2- mg/l 0.001 0 0.002 0 0.002 0.002 0.002 0.005 1,0

NO3- mg/l 0.037 0.027 0.035 0.003 0.035 0.028 0.035 0.033 15

SO42- mg/l 15.2 18.6 14.6 25.2 14.2 15.4 20.4 22.6 400

COD mg/l 6.16 7.2 8.36 10.5 9.5 10.7 5.92 7.5 4

Coliform MPN/100ml 1 3 3 4 5 4 1 3 3

Thng s n v

Kt qu QCVN

09:2009 Mu 5 Mu 6 Mu 7 Mu 8


pH mg/l 3.4 4 6.3 3.57 5.4 4.84 3.8 5.69 5,5-8,5

TSS mg/l 10 5 4 3 12 20 6 10 1500

Cl- mg/l 5.9 56.8 16.9 31.95 15.1 21.3 10.5 24.85 250

cng ton phn mg/l 107 140 206 123 222 147 95 161 500

NH4+ mg/l 0.062 0.063 0.061 0.193 0.055 0.312 0.051 0.067 0,1

NO2- mg/l 0.002 0.006 0.002 0.077 0.001 0.012 0.001 0.003 1,0

NO3- mg/l 0.035 0.034 0.034 0.096 0.038 0.042 0.034 0.03 15

36

Thng s n v

Kt qu QCVN

09:2009 Mu 5 Mu 6 Mu 7 Mu 8


SO42- mg/l 6.4 5.1 8.6 6.4 18.2 15.7 11.4 13.2 400

COD mg/l 6.72 8.3 5.62 6.7 6.54 7.2 8.37 9.2 4

Coliform MPN/100ml 2 3 4 3 3 3 4 4 3

Ngun: quy hoch tng th vng Ty Nguyn Vin Quy hoch Thy li - 2013

37

- nh gi chung v cht lng nc di t trn lu vc sng Srepok:

Qua kt qu phn tch cht lng nc ngm t nm 2002 n nay cho thy cht lng nc di t c biu hin nhim bi pH thp, hm lng COD v vi khun tng i cao vt quy chun cht lng nc ngm 09:2008 cho php. Hm lng vi khun ti mt s ging c hm lng Coliform vt tiu chun hng trm ln.

Nhm amoni, tng cng, kim loi nng vn nm trong gii hn cho php. Tuy nhin hm lng cht hu c, vi sinh vt c chiu hng tng cao trong thi gian gn y. Ngun gc gy nhim c th l do cc cng trnh v sinh, cc cng trnh x l cht thi chn nui, nc thi sinh hot khng qua x l, ch yu l t thm nn xy ra hin tng thm nc thi lm nhim cc tng nc di t.

3. Nhng vn mi trng chnh trn lu vc sng Srepok.

3.1. Tc ng ca thy in n mi trng.

Trn lu vc sng Srepok ch yu l trn a bn tnh k Lk h thng khai thc in nng t bc thang thy in trn dng chnh sng Srepok v h thng thy in va v nh trn cc dng nhnh sng Srepok (xem bng 9).

Bng 9: Bng tng hp cc cng trnh thy in trn lu vc sng Srepok

TT Cng trnh Sng Nlm

(MW)

a im XD Tin

I Dng chnh Srepok

1 Bun Tua Srah Krng N 86 Huyn Lak HT 2009

2 Ch Pong Krng Krng N 7.5 H. Krng n NCKT

3 Bun Kp Srepok 280 H. Krng Ana HT. 2009

4 ray Hlinh Srepok 0.48 TP. Bun M Thut

Trc 1975

5 ray Hlinh 1 Srepok 12 TP. Bun M Thut

HT. 1989


HT. 2007


HT. 2008

8 Ho Ph Srepok 29 TP. Bun M

Thut HT. 2013

9 Srepok 3 Srepok 220 H. Bun n HT. 2010

10 Srepok 4 Srepok 80 H. Bun n HT. 2010

11 Srepok 4A Srepok 64 H. Bun n HT. 2013

12 rng Phok Srepok 26 H. Bun n NCKT

II Sng nhnh

II a Krng Kn

1 ak NTeng ak NTeng 9.6 H Krng N HT

IIb Krng Ana

38

TT Cng trnh Sng Nlm

(MW)

a im XD Tin

1 Ea Kar Ea Kar 3 H. Krng Bng HT. 2011

2 Krng Kmar Krng Kmar 12 H. Krng Bng HT. 2008

3 Krng Kmar 2 Krng Kmar 1.2 H. Krng Bng NCKT

4 Ea Ktour Krng Bng 9.3 H. Krng Bng NCKT

IIc Ea Hleo

1 Ea Sp 3 Ea Sp 6.4 H.Ea Hleo HT. 2011

2 Sau p Ea Sp Thng Ea Sp 1.7 H.Ea Sp NCKT

3 Ea Hleo Ea Hleo 0.355 H.Ea Hleo HT. 2002

4 Ia Hiao 3 Ia Hiao 4 H. Ea Hleo HT. 2012

5 Iapuch 3 Iapuch 16 H. Ch Prong HT. 2009

6 Ia Lp Ia Lp 0.2 H. Ch Prong HT. 1993

7 Ia Mear Ia Mear 1.8 H. Ch Prong HT. 2005

8 Ia rng 1 Ia rng 1.2 H. Ch Prong HT. 2003



11 C Mt Ia rng 5 H. Ea Sup QH

12 Eawy Ia rng 5 H. Ea Hleo QH

II d Sng nhnh Srepok

1 Ea Tul Ea Tul 6 Bun n HT. 2011

Ngun: Cty t vn thy in 1 -2013

Trn dng nhnh v dng chnh c tng s 30 cng trnh, tng cng sut lp my Nlm = 912.135 MW. Sn lng in tng bnh qun hng nm trn 15%. t c nhng kt qu trn ngnh nng lng tin hnh xy dng hng lot cc cng trnh thy in, v phng din no nhn c s ng tnh ca cc nh qun l, cng nh khch hng ca EVN. Tuy nhin vic pht trin thy in thiu kim sot v ang nh hng n mi trng:

- Tnh trng cn kit ngun nc mt:

Sng Srepok l mt nhnh ln ca sng M Cng, hng nm tng lng nc n ton

lnh th tnh k Lk, k Nng trn cc lu vc chnh nh Srepok 9 t m3, Ea HLeo

1,98 t m3. Ti nguyn nc mt ln, nhng do phn b khng u, trn lu vc c ma

ma ko di d gy ng lt v mt ma kh lu vc sng Srepok hu nh khng c ma,

thiu nc nghim trng. Vic khai thc qu mc dng chy ca sng Srepok v cc chi

lu ca n, cng vi tnh trng ph rng lm nng ry lm cho tnh hnh ngy cng

nghim trng.

Theo bo co nh gi tc ng mi trng thy in Srepok 4A do cng ty C phn

T vn Xy dng in 4 thc hin, cng trnh thu in Srpk 4A c nghin cu xy

dng b sung vo h thng bc thang thu in trn sng Srepok. Thu in Srepok 4A

khng xy dng p, khng c h cha, tn thu ngun nc t thu in Srpk 4 pht

39

in. Lu lng x qua nh my thu in Srpk 4 tr v sng Srpk 8,23m3/s, phn cn

li chuyn qua knh dn v nh my Srpk 4A pht in, nc s theo knh dn di

khong 15 km, c o bng qua 3 x Ea Wer, Ea Huar v Krng Na, huyn Bun n.

Sau khi phc v pht in cho nh my, lng nc ny s c tr v sng Srpk, cch

ni nhn nc khong 20 km ng sng. Nh vy nhn t trn cao, sng Srepok nh c

thm mt nhnh, tuy nhin n s sm cn kit nhnh chnh khi thy in Srpk 4A i

vo hot ng. Theo c tnh, 20km sng Srpk i ngang vn quc gia khng cn

nc khi cng trnh thy in Srpk 4A i vo hot ng do lng nc t nh my

Thy in Srpk 4 x trc tip xung sng Srpk ch cn li 8,23 m/giy, trong khi

dng chy t nhin ca sng l 220 m/giy, tc ch bng 1/26 so vi dng chy t nhin

khin c mt on sng di s cn kit nc.

Hnh 23: Sng Srepok ti h lu thy in Srepok 4 (bn phi l knh dn nc sang

thy in Srepok 4A)

Vi mc nc qu thp quanh nm nh vy s nh hng ln n ch dng chy, n h sinh thi khu vc sng ny v khu du lch sinh thi Bn n cng s b nh hng nghim trng.

- Tnh trng cn kit ngun nc ngm:

Theo bo co ca s Nng nghip v PTNT tnh k Lk, tnh hnh hn hn vo

ma kh trn a bn tnh ang din ra ht sc nghim trng, nhiu vng ca Ty Nguyn

c th b sa mc ha do khng c ngun nc cp. T nm 1997 tr li y, tnh trng cht

ph rng u ngun lm lm nng ry, c bit l trng cy c ph. Rng k Lk b

tn ph vi tc chng mt, che ph gim t 65 phn trm xung ch cn khong 42

phn trm trong 10 nm qua, nn lng nc ma hu ht tr thnh nc l, lng nc

c th thm xung c tng nc ngm l rt hn ch.

Theo ti liu nghin cu ca on iu tra Quy hoch Ti nguyn nc 704 thc

hin quan trc ti nguyn mi trng nc di t khu vc k Lk v k Nng, cho

40

thy: hin nay, mc nc ngm k Lk v k Nng thay i rt ln nhiu vng

gim 20% so 10 nm trc; v ma kh, mc nc ngm trung bnh thp hn nhng nm

u thp nin 80 ca th k trc khong 1,4 1,5m, thm ch c ni b tt gim t 4 5m

c bit vng Nam ng cn khng nc ngm cp cho sinh hot. c bit, nhng

vng trng nhiu cph, do phi bm ht nc qu ln vo ma kh nh Bun Ma

Thut, Krng Buk, Krng Pch, Krng Ana, C Mgar (Dk Lk), mc nc ngm gim

t 4 5 m so vi nhng nm u thp nin 80. Qua kho st ca on 704 cho thy mt

s vng nh Krng Pak, Lak , Krng Buk v vng pha ng Bun Ma Thut mc

nc ngm tim nng khng cn nhiu nh 5 nm trc. V d vng Krng Pak, Lak

nm 2004 c th khai thc ti a 0,4-0,6 triu m3/ngy, th nay cn cha y 400 nghn

m3/ngy.

Hin nay vic khai thc qu mc khin tng cha nc b km i, vic khai thc

nc ngm ba bi cng lm tng nc ngm b suy gim mnh. Nhiu gia nh hin nay

do nhu cu cp thit v nc ti thu my khoan a cht (c ng knh 15cm)

khoan xung lng t t 70-80m, ri dng in ba pha ht nc ln ti cho c ph, h

tiuiu ny gy hu qu khn lng, lm thng tng nc ngm nhiu ni v l mt

trong nhng nguyn nhn trc tip e da thm tnh trng cn kit nghim trng lng

nc ngm ak Lak ni ring, Ty Nguyn ni chung.

Mt yu t khc l bin i kh hu cng c th lm mc nc ngm hin nay b

suy gim. Tnh trng nc ngm suy gim mnh gy nh hng ln n canh tc nng

nghip, c bit vi cph, cao su. Bn cnh , nh hng ca thu in, khi mc nc

ngm gim, th nc v cc h thu in cng gim. Hin nay, tnh trng thiu nc

nhiu h thu in trn lu vc th hin rt r. Nu c tip tc khai thc nc ngm

ba bi nh hin nay, mc suy gim mc nc ngm s cn nghim trng hn na, s tc

ng trc tip n i sng ca nh kinh t ca ngi dn.

41

Hnh 24: tnh trng cn kit ngun nc mt v nc ngm trn lu vc sng Srepok

- Si l v bi lng lng dn:

Trong cc thy in bc thang trn sng Srepok th thy in Bun Tua Srah xy dng trn sng Krng N thuc huyn Krng N. Do pha h du nh my thy in l vng ng bng tp trung ng dn c v l vng trng cy cng nghip v nng nghip nh la, ng, khoai, c ph, iu vvDo iu kin a hnh, dng sng un khc i qua a bn cc x Bun Choh, Nm Ndier, c Xuyn, Qung Ph, c Nang ca huyn Krng N. Thc t theo ccs liu kho st nhng nm trc y, thi gian ngp lt ln ch yu thng ri vo cc thng ma ma thng 9, 10 v 11 (nm 2007, xut hin vo u thng 8); l tiu mn ch yu xut hin trong cc thng 7, 8, 11 v 12. Tuy nhin khi nh my thy in Bun Tua Srah i vo hot ng t nm 2009 n nay gy ra tnh trng ngp ng v st l nng ngay trong ma kh. T u nm 2010 n cui thng 3, theo cc con s thng k c tng cng gn 40 ha cy trng b ngp do vic x nc ca nh my thy in Bun Tua Srah. Theo bo co ca s Nng nghip v PTNT tnh c Nng th hin nay din tch mt t do thy in Bun Tua Srah gy ra vo khong 100 ha.

V vic st l b sng: Sng Krng N on ngay sau knh x nc ca Nh my Thy in Bun Tua Srah chy qua a bn nm x: c Nang, Qung ph, Bun Choah, Nm Ndier, c Xuyn (thuc huyn Krng N) c chiu di t 30-35 km theo tuyn cong ca trc sng. Vn st l b sng xy ra trm trong trong ma kh, khi m thy in vn hnh vi lu lng thay i mnh, bt thng: hng ngy, thng t 18-19 gi, bt u x nc, n m t 23-24 gi, lu lng thng t cao nht tng ng vi 200 m3/giy, n tra hm sau, lu lng tr v gi tr bng 0 khi nh my thy in ngng hot ng ton b. Theo cc s liu kho st th lu lng trung bnh t nhin trc y lun n nh theo ngy m t 12-16 m3/giy).

Hnh 25: Sng Krng N ti h lu nh my thy in Bun Tua Srah x Nm

Ndier huyn Krong N ngy 5/5/2013

Vi hai b c rt nhiu v tr un cong thay i lin tc dc sng to ra cc bn l v bn bi lm xi v di chuyn bn ct t v tr ny n v tr khc Trong khi , a cht ven sng ch yu cc lp ph sa l ct kt, st bt khi gp tnh trng mc nc thay i lin tc trong ngy b ph v st l. Theo cc s liu iu tra ca s Nng

42

nghip v PTNT tnh k Nng th pha h lu sng Krng N on chy qua x c Xuyn, huyn Krng N gy xi mn v st l nng bnh qun t 1,5-2m/ngy m, tc trung bnh st l t 1,5- 2 m theo chiu ngang b sng trong mt ngy m. Vng b st l l t mu m, c nhn dn trng cy bp, la, u 2-3 v/nm nng sut cao nh bp lai t t 1.214 tn /v/ha, la t 6-10 tn/ v/ha (ngun: Hin trng sn xut nng nghip tnh k Nng -2012).

Bn cnh , mt s cng trnh thy li, trm bm ven sng Krng N cng c nguy c b cun tri trong nm nay hoc vi nm ti nh: knh ti v nh trm ca cc trm bm c Rn c u t 55 t ng ang trong qu trnh xy dng; trm bm Bun Choh c u t xy dng vi kinh ph 45 t ng a vo vn hnh trong hn mt nm nay, nhng hin nay ch cn cch b sng chng 20-25 m so vi 50 m mt nm trc y trm bm Bun Sc v D12 khng th hot ng do b bt ming ca vo ca ng ht, khng th hot ng; vng sn xut nng nghip ca huyn b thu hp Ngoi ra, vic thay i t ngt lu lng v vn tc dng chy cn e da tnh mng ca ngi dn thng qua li v sinh sng ven sng Krng N(ngun: Hin trng sn xut nng nghip tnh k Nng -2012).

Suy gim dng chy bn ct h du do cc cng trnh thy in khng c thit k cng x y lm thiu ht lng ph xa b sung mu cho t nng nghip h lu, ct sn si, thm vo l hin tng khai thc ct ang din ra kh kim sot lm nh hng hnh thi sng v sinh k ca ngi dn sng da vo ti nguyn ny.

- nh hng n h sinh thi:

Vic ph rng u ngun, trong c c nhng khu vc vn quc gia, khu bo tn, xy cc cng trnh ca nh my thy in trn lu vc sng Srepok lm mt rt nhiu din tch rng, mt i tnh a dng sinh hc trong khu vc, trong khi vic trng b rng li khng c thc hin y v hu ht cc cng trnh khng b tr c hoc b tr khng qu t trng rng nhm b li din tch rng mt.

Theo kt qu iu tra ca Vin Nghin cu Nui trng Thy sn III, trong lu vc Srepok c khong 200 loi c trong 8 loi c nhp ni, 41 loi c gi tr kinh t v 14 loi c tn trong sch Vit Nam... c bit huyn Bun n c nhiu loi c bn a c kch thc ln v s lng nhiu nh sc da (Probarbus jullieni Sauvage) 52 kg (1997), c lng (Mystus wyckioides) 50 kg (1997), c mm tru (Bangana behri) 15 kg (2004), c tc k (Bagarius yarrelli Sykes, B. bagarius) 24 kg (2000)... (ngun: iu tra nhanh ca Vin Nghin cu Nui trng Thy sn III). Vic xy dng thy in trn dng chnh sng Srepok b chn dng, cc loi c qu him nh: c lng, c mm tru ngy cng khan him. Cui nm 2013 khi Nh my Thy in Srepok 4A i vo hot ng s lm kh cn on sng di 20 km, h sinh thi phong ph ti on sng ny thuc khu bo tn thin thin vn Quc gia Yok n s khng cn. Ti cc p thy in ang xy dng hoc ang hot ng u khng xy dng ng cho cc di tr, iu ny s gy nh hng n cc loi c di c v tc ng n ngun li thy sn phong ph trn lu vc.

Sp ti, thy in cui cng trn dng chnh sng Srepok s c xy dng (ang trong giai on nghin cu kh thi), thy in rng Phk c cng sut 26MW (x Krng

43

Na, Bun n) c xy dng. Tuy nhin v tr xy thy in rng Phk ti tiu khu 430, 431, 451 nm gia vng li vn quc gia Yok n thuc phn khu bo v nghim ngt ca Vn Quc gia. Thy in xy dng trong vng li s nh hng ln n ngun nc cng nh

cng tc bo tn a dng sinh hc v l mi e da trc tip n mi trng v cng tc bo v rng... xy dng thy in rng Phk s c gn 53ha rng c dng vn quc gia Yok n b n h, chim dng vnh vin v 10ha b chim dng tm thi trong tng s hn 115 nghn ha rng thuc vn Quc gia Yok n ang qun l. y cng l mt loi rng c hu ca vng Ty Nguyn - Vit Nam ni ring v ca vng ng Nam ni chung.

Ngoi vic nhim mi trng, tc ng n h sinh thi th vic dng nc lng h ca thy in rng Phk s to iu kin cho lm tc xm nhp v vn chuyn g lu bng ng thy... ng Trn Vn Thnh, quyn gim c vn quc gia Yok n, cho bit vic xy dng thy in rng Phk trong vng li s nh hng ln n cng tc qun l, bo v rng ca vn quc gia Yok n v lu di. Trong qu trnh thi cng, xe my v cc thit b khc, c bit l vic n mn ph , s gy nhim mi trng sinh thi, gy ting n lm ng vt hoang d b i ni khc.

Hnh 26: a im d kin xy dng thy in Drng Phk thuc vng li Vn Quc gia Yok n, phn khu cn bo v nghim ngt.

- Nguy c v p thy in:

Ngoi 12 cng trnh thy in trn dng chnh, cn c 18 cng trnh thy in trn dng nhnh lu vc sng Srepok. Vic xy dng cng trnh thy in, nht l cc cng trnh nh do a phng qun l v xy dng khng tun th nghim ngt cc quy trnh xy dng v kim tra gim st c th s gy ra hu qu v p. mt v d in hnh l cng trnh thy in k Rng 3 c xy dng ti x T Long, huyn akrng tnh Quang Tr vi cng sut 8MW, c p cao 20 mt, di 146 mt c dung tch h cha

44

3,4 triu m3 b v p ch sau 15 ngy nghim thu, pht in gy ra, gy thit hi c tnh khong 20 t.

Thy in Ia Krl 2, xy dng ti x Ia Dom huyn c C, tnh Gia Lai vi cng xut 5,5 MW b v p chnh di khong 40 m lm ton b hn 5 triu m3 nc trong lng h trn xung vng h du, gy l qut dc tuyn sui Ia Krl vi chiu di hn 10 km t p thy in n sng S San. V p gy thit hi hn 200ha cy trng v hoa mu ca hn 120 h dn. c tnh thit hi hn 3,6 t ng.

p thu in k rng 3 v ch sau 15 ngy

nghim thu, pht in Thit hi do v p k rng 3 gy ra

Hnh 26: hnh nh v p thy in k Rng 3

Theo Ban Ch o Ty Nguyn, vic pht trin thy in Ty Nguyn nhng nm qua v ang li nhiu tc ng n mi trng x hi v sinh thi, nht l trong cng tc n b, ti nh c, tc ng xu n mi trng. Ton khu vc Ty Nguyn ang c 287 d n thy in, vi tng cng sut gn 7.000MW. Hin c 84 d n c a vo s dng, cng sut gn 5.000 MW. Cc d n cn li ang c xy dng v ln k hoch u t. ng trc nhng vn tc ng xu n mi trng trn lu vc, Ban Ch o Ty Nguyn phi hp vi B Cng thng r sot nh gi li quy hoch pht trin cc cng trnh thy in gn vi vic s dng t ai, ti nguyn, bo v mi trng sinh thi v m bo khng gian sinh sng ca ng bo cc vng d n ti Ty Nguyn, loi b nhng d n hiu qu thp, nh hng n rng v sn xut nng nghip. Loi b nhng d n c tc ng ln ti mi trng, i sng ngi dn v tm dng xy dng cc d n thy in (ngun: Bo Gia Lai online ngy 26/6/2013).

- V knh dn nc thy in Srepok 4A.

Tn dng trit kh nng thy in ca sng Srepok, EVN xy dng thy in

Srepok 4A khng xy dng p, khng c h cha, tn thu ngun nc t thu in Srpk 4 pht in. Nc s theo knh dn di khong 15 km, c o bng qua 3 x Ea Wer, Ea Huar v Krng Na, huyn Bun n v nh my Srpk 4A pht in.

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Trong qu trnh thi cng vo khong 15g30 ngy 29/9/2013, knh dn dng thy in Srpk 4A bt ng v toang 2 bn, cun tri hng chc ha la v hoa mu ca ngi dn. on knh b v di khong 50m mi bn khin hng chc ha la, hoa mu ca ngi dn dc 2 bn knh l thn 1, bun NDrch A v bun Giang Png (thuc x Ea Huar, huyn Bun n, k Lk) b ngp, h hi.

V knh dn dng thy in Srpk 4A Thit hi v hoa mu do v knh

Ngun: Bo Lao ng online ngy 29/9/2013

3.2. Tc ng ca pht trin kinh t, x hi n mi trng:

- S dng phn ha hc thuc bo v thc vt:

Theo thng k n nm 2010 din tch c ph ca ring tnh k Lk l 182,4 ngn ha, 71,8 ngn ha la. Tnh k Nng c Trong nhng nm gn y, ho cht bo v thc vt c s dng rng ri trong sn xut nng nghip, gia tng c v khi lng v a dng v chng loi. Ha cht bo v thc vt thng s dng l: Thuc tr su, thuc tr bnh, thuc dit c v cc loi thuc khc, khong gn 200 loi thuc tr su, 83 loi thuc tr bnh, 52 loi thuc dit c, 8 loi thuc dit chut v 9 loi thuc kch thch sinh trng c s dng trn lu vc. Trong nhiu nht vn l nhm hp cht ln hu c, clo hu c thuc nhm c t I n IV, sau l nhm Cacbonat, Pyrethroid thuc th h IV.

Huyn s dng thuc bo v thc vt nhiu nht l Krng Ana (2,04kg/ha/nm), tip n l huyn Krng Nng (1,83kg/ha/nm), t nht l huyn Bun n, huyn Krng Bng (0,16kg/ha/nm). X s dng nhiu nht l x Dlie Ya, huyn Krng Nng (13,2 tn/nm), x Ha Hip, Ea Tiu, huyn Krng Ana (8 tn/nm) (ngun bo co hin trng mi trng tnh k Lk -2010). Vi liu lng s dng nh trn, cng vi quy trnh s dng cha m bo yu cu k thut. Phn bn, thuc bo v thc vt (BVTV) c s dng ht pht tn vo ngun nc mt, nc ngm gy nhim ngun nc nh hng ti sc khe cng ng.

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- Nc thi, rc thi

Theo s liu thng k nm 2008, ch tnh ring tng dn s trn a bn tnh k Lk l 1,778 triu ngi, trong c khong 22% dn s sng ti vng th. Tng lng rc thi sinh hot pht sinh t vng th khong 260 m3/ngy, tng t 15-25 % so vi nhng nm trc nm 2005. Tnh k Nng vi dn s th nm 2010 l 76.329 ngi, c tnh lng thi hng ngy l 6.106 m3 thi ra mi trng. Tng lng nc thi pht sinh t cc nh my, khu cng nghip vo khong 11.728 m3/ngy m. S gia tng khi lng cht thi rn th l do s pht trin nhanh ca nn kinh t, tc th ha ngy cng cao, mc sng ca con ngi ngy cng tng. Ring ti thnh ph Bun Ma Thut, khu vc ni thnh c khong 326.892 dn cng vi hot ng ca cc c s sn xut, nh hng, bnh vin, thi ra lng rc sinh hot trung bnh 260 tn/ngy. i vi rc thi y t, l loi rc thi nguy hi bao gm cht thi ly nhim, cht thi ha cht, dc phm v cht thi phng x c cha cc hp cht c cc c tnh gy hi trc tip hoc tng tc vi cc cht khc nh hng xu ti mi trng v sc kho cng ng.

Tnh k Lk c 21 Bnh vin, 15 Trung tm y t cp huyn, 1 Trung tm Chm sc sc khe b m - tr em v 1 tri phong, ngoi ra cn c 184 trm Y t x phng v cc c s khm cha bnh t nhn vi tng s ging bnh l 3.785 ging. c tnh vi tc thi l 0,5kg/gng bnh/ngy m th lng cht thi rn y t ti cc Bnh vin v Trung tm y t huyn khong 1.892 kg/ngy, trong c khong 757 kg rc thi y t nguy hi c thu gom ring. Ti tnh k Nng cht thi nguy hi ch yu pht sinh t cc bnh vin, c s y t, cc nh my v cc KCN. Tng lng cht thi pht sinh nguy hi trn a bn tnh theo s liu thng k nm 2010 l 0,087 tn/ ngy.

Thnh phn rc thi y t rt a dng v nguy him, nu khng phn loi, qun l v x l tt s l ngun ly nhim ca nhiu loi bnh tt nh: HIV, vim gan, cc bnh nhim khun, c bit trong iu kin nhit i m gi ma s l mt trong nhng ngun to ra cc dch bnh nguy him cho nhng ngi lm vic ti bnh vin, nhng ngi lm cng tc thu gom, vn chuyn, x l v i vi dn c xung quanh.

- Sc p v tng dn s v di dn trn lu vc:

Tc gia tng dn s c k hoch v t do trong thi gian qua v ang c nhng tc ng n ti nguyn rng, ko theo nhu cu ngy cng gia tng v t cho canh tc nng nghip. Mt s din tch rng b chuyn i khng theo quy hoch sang canh tc nng nghip. V vy, lm thay i din tch rng t nhin. Theo s liu thng k, dn s tnh k Lk nm 2005 l 1.715.000 ngi, n nm 2010 dn s tng ln 1.754.000 ngi, t l tng dn s khong 1,55% (ngun: Nin gim thng k 2010). Theo kt qu iu tra cui nm 2010 ca tnh k Nng dn s ton tnh l 510.570 ngi tng ln n 28,43% so vi nm 2004, lc mi tch tnh, ton tnh c 397.536 ngi (Nin gim thng k tnh k Nng nm 2010). iu ny cho thy, ngoi lng dn s trn a bn tnh, cn c mt lng ln dn di c ch yu t cc tnh pha Bc vo k Nng lm cho dn c trong tnh tng vt. Hin nay dn di c t cc tnh pha Bc vn tip tc di chuyn vo tnh k Nng, t nm 2004 n 2009 c 1.489 h vi 4.300 khu t 40 tnh thnh

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di c n. Phn ln dn di c t do l nhng h ngho, hon cnh kinh t kh khn, ngi dn di c ch yu ph rng lm nng ry, nht l rng gi, rng u ngun, iu ny tc ng xu n quy hoch lm hu hoi mi trng sinh thi. l mt trong nhng nguyn nhn chnh lm gim din tch rng b tn ph vi tc chng mt, che ph gim t 65% xung ch cn khong 42% trong 10 nm qua.

4. C s la chn yu cu v phng php tnh ton nhu cu nc dnh cho mi trng trn lu vc.

Theo iu 2: Gii thch t ng trong lut Ti ngun nc 2012 ghi r: Dng chy ti thiu l dng chy mc thp nht cn thit d duy tr dng sng hoc on sng nhm m bo s pht trin bnh thng ca h sinh thi, thy sinh v bo m mc ti thiu cho hot ng khai thc, s dng ngun nc ca cc i tng s dng nc . Trn dng chnh sng Srepok b cht ra nhiu on bi 3 h cha Buon Tua Srah, Buon Koup v Srepok 3 vi dung tch trung bnh mi h > 60 triu m3 v 3 p dng Dray Hling, Srepok 4 v Srepok 4A. Theo Hip nh Mekong 1995 v cc th tc lin quan ca y hi sng Mekong th dng chy ti thiu qui nh ti iu 6 khng nh hn dng chy t nhin thng nh nht chp nhn c ca tng thng ma kh. y dng chy sang pha Campuchia c xem xt ti v tr kim sot l trm thy vn Bn n (Hnh 4.1).

Hnh 4.1 ng qu trnh dng chy ma kit Bn n

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5. Tm quan trng ca vic duy tr lng nc cho mi trng trn lu vc.

Hin nay nhiu lu vc sng ang b suy thoi nghim trng v khng m bo

dng chy h du m nguyn nhn chnh l do vic mt cn i trong khai thc, s dng

nc cng nh vic coi nh bo v mi trng. Tnh trng ny din ra cc thm ha

nh: thiu nc cho cc nhu cu s dng h du, s cn kit dng chy trong ma cn,

dn n tnh trng t dng ca sng vng h du (in hnh l thy in Srepok 4 khng

x nc xung h du, ch x xung sng Srpk 8,23 m/giy, trong khi dng chy t

nhin ca sng l 220 m/giy, tc ch bng 1/26 so vi dng chy t nhin khin c mt

on sng di trn 20 km cn kit nc). S gia tng cc him ho do nc gy ra nh l

lt v sa bi thu ph; s suy gim cht lng nc khin cho nc sng khng cn s

dng c; s gia tng xm nhp mn vng ca sng. Do tnh cp thit v khai thc v

s dng hp l ti nguyn nn trong vi thp k gn y cc nc trn th gii quan

tm n gii hn khai thc v duy tr dng chy mi trng. Dng chy mi trng

c nghin cu v ng dng trong quy hoch v qun l ngun nc cc lu vc sng

hn 25 nc trn th gii trong c M , c, Nam Phi....

i vi Vit Nam, dng chy mi trng mi c quan tm trong khong 15 nm

tr li y khng phi hon ton do nhn thc m do trc y cht lng nc trn cc

sng cha b nhim. Trong chin lc quc gia v ti nguyn nc n nm 2020 c

chnh ph thng qua thng 4/2006 a ra 6 mc tiu bo v ti nguyn nc trong c

mc tiu v dng chy mi trng l: Bo m dng chy ti thiu duy tr h sinh thi

thu sinh theo quy hoch c cp c thm quyn ph duyt, trng im l cc sng c h

cha, p dng ln, quan trng. Trn lu vc sng Srepok, n nay mc d c mt s

s liu v cht lng nc nhng vn cn kh ri rc. Chng ta cng a ra cc quan

im v dng chy mi trng thng qua vic k tha cc phng php lun v phng

php ca th gii tuy nhin cn phi lc gin i cho ph hp vi thc trng s liu v

iu kin ca Vit Nam.

mk17_environmental water demand of the srepok catchment_vietnamese.pdf

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