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Nghien cu''''u & Trao doi KET QUA NGHIEN CLfU DANH GIA 6 NHIEIVI, PHU DU''''O''''NG Nu''''ac MAT CUA MOT SO TUYEN KENH NOI SONG TIEN SONG HAU THUOC CAC TINH VTNH LONG, DONG THAP, TIEN GIANG ThS Cao Phu''''O''''ng Nam,[.]
Nghien cu'u & Trao doi KET QUA NGHIEN CLfU DANH GIA NHIEIVI, PHU DU'O'NG Nu'ac MAT CUA MOT SO TUYEN KENH NOI SONG TIEN SONG HAU THUOC CAC TINH VTNH LONG, DONG THAP, TIEN GIANG ThS.Cao Phu'O'ng Nam, KS Tran Van D i e p - Vien Thuy Lgi va Mdi Trudng TS Du'O'ng Van Vien, KS Vu Hoang Thai Dipcng - Trudng Dai Hpe Thuy Lgi C hdt lugng ngudn nuac ludn cd mpt y nghia cue ky quan trong, ddng vai trd quyet djnh den suphdt triin kinh ti xa hpi, ddc biet san xuit ndng nghiep, thiiy san vd dai song hang ngdy cua dan cu Di gdp phin nim dugc hien trang chit lugng nuac mat nhdm tim kiim giai phap bao ve, sir dting hgp ly vd phdt thin tdi nguyen nirac mat viing, chiing tdi da tiin hdnh khdo sat, nghien ciru chit lugng nuac mat ciia cac kenh Nha Man Tu Tai, Cin Tha Huyen Hdm vd Nguyen Van Tiip B tren dja ban tinh VTnh Long, Ddng Thap va Tiin Giang thupc he thong kenh ndi sdng Tiin va sdng Hau viing DBSCL Thai gian nghien ciru tir thdng ndm 2008 din thang nam I Dat van de ITnh vyc trpt, dd vung DBSCL tieu thu Chit lugng ngudn nude ludn cd y nghTa eye ky quan trpng, ddng vai trd quylt djnh d | n sy phat trien kinh t l xa hdi, dac biet san x u l t ndng nghiep, thijy san va ddi sdng hang cua dan cu Da bao ddi, nay, sy tru phu cua vung chau tho DBSL ndi ehung va cua vung d i t nam gi&a sdng T i l n , sdng Hau ndi rieng, la mdn qua dugc thien nhien ban tang, dd ea vung d i t da dugc hudng thu bdi ngudn nude ngpt ehua d i y phu sa cua ddng sdng Tien, sdng Hau thude he thing sdng Me Kdng Tuy ehi chilm khoang 30% dien tich d i t ndng nghiep nhung hang nam, DBSCL ddng gdp cho ea nude han 50% san lugng Itja, khoang 92% kim ngach xult khiu gao, han 60% gia tri thuy san x u l t khau Hang nam nganh Ndng nghiep Viet nam su dung x l p xi trieu t i n phan bdn cac loai va phan bdn trd vat t u d i u vao quan trpng nhit khoang 400.000 t i n N, 120.000 t i n P2O5 va 120.000 t i n K2O, nhung den tay ndng dan thi hieu qua si> dung r i t thip, lugng phan m i t di qua trinh boc hai, tham t h i u , rCpa trdi len tdi tren 60%, anh hudng Idn den mdi trudng, den ehit lugng ngudn nude mat Thdi gian trdi qua, sy phat triln kinh te xa hdi da ed nhiing tae ddng d i n mdi trudng, den chit lugng nguon nude mat De gdp phan n i m duge hien trang c h i t lugng nude mat nham tim kilm giai phap bao ve, su dung hgp ly va phat triln tai nguyen nude mat vung, ehijng tdi da tien hanh khao sat, nghien cij'u c h i t lugng nude mat cua cac kenh Nha Man T u Tai, C i n Tha Huyen Ham va Nguyin Van Tilp B tren dja ban tinh VTnh Long, Ddng Thap va T i l n Giang thupc he t h i n g kenh noi sdng T i l n va sdng Hau vung DBSCL Thdi gian nghien CLPU tu thang nam 2008 den thang nam 2009 Tap chi Khi tufgfng Thuy van * Thang 5/2009 29 S« 9'-ôằ>ôi*** ã**!** " ã Nghien cifu & Trao doi Phu'O'ng phap nghien CLPU a Dja diem va th&i gian nghien nam vung dy an cac nam 2006, 2007, 2008 ciru 2) Diiu tra, phdng vin ndng hp Tuyen kenh nghien cuu: Nha Man T u Tai tai vi T i l n hanh d i l u tra va phdng v i n hd dan ve san tri vam Chg Ba sdng Hau theo hudng Bac, di x u l t ndng nghiep, mdi trudng, trinh dp hpc v i n , so qua dja phan cac huyen Binh Minh, Binh Tan, Chau hp, thu nhap Sd hd da dugc phdng v i n : 500 hp va Thanh Dong Thap; kenh C i n Tha Huyen Ham chay 600 philu dieu tra xa hdi hpe qua huyen Chau Thanh, Lai Vung tinh Dong Thap huyen Binh Tan tinh VTnh Long; kenh Nguyin Van 3) Phuang phdp liy miu, bao qudn va phdn tich mdu Tilp B chay qua huyen Thap Mudi tinh D i n g Thap, huyen Cai Be tinh T i l n Giang Moi tuyen kenh ed + Phuang phap l i y m l u , bao quan m l u chilu rpng trung binh 50 m, sau 2-3 m, dai khoang Phuang phap l i y m l u , bao quan m l u : m l u 26 km Phuc vu tudi tieu, d p nude sinh hoat eho dugc l i y theo TCVN 5996-1995 va dugc phan tich tren 27.000 ty nhien va 23.000 d i t ndng v l d i n phdng thi nghiem Bao quan theo nghiep chij y l u la lija vij va vudn cay an trai Chpn TCVN 5993-1995 12 dilm tren moi tuyen kenh, t i l n hanh khao sat, l i y m l u Thdi gian khao sat l i y m l u , danh gia tu thang Cd dinh chi tieu COD bang dung djch H2SO4 4M, H c l djnh b i n g dung dich CdCI 2%, T i t ca nam 2008 den thang nam 2009 cac may d i u dugc dyng chai F^E hoac thuy b Phwang phap thye hien tinh, bao quan, tru lanh d nhiet dp C va van chuyen v l phdng thi nghiem Phan tich cac chi 1) Thu thdp sd lieu Tiln hanh thu thap s l lieu nien giam thing ke cac tieu theo phuang phap dugc trinh bay d bang huyen nam 2006, 2007, bao cao kinh t l xa hdi hang Bang Chi tieu va phwang phap phan PhvTo'ng phap p h a n tfch Chl tieu p h a n tfch 30 tfch pH Do tai hien tiirSng bang may WQC 24 Nhiet d6 Do tai hi6n trtfang b^ng m^y WQC 24 DO (mg O2/L) Do tai hien Infclng bang may WQC 24 Nhiet ("C ) Do tai hien tiifdng bang mdy WQC 24 BOD (mg O2/L) Winkler cai tien COD (mg O2/L) TCVN 6491-1999 TSS (mg/L) 2545F- Std.Method(p 2-57) N-ts (mg/L) Kjeldalh method P-ts (mg/L) Total phosphorus by spectrophotometry methoc Fe (mg/L) AAS method Total coliform (MPN/lOOmI) TCVN-MPN method H2S(mg/L) 4500D- Std.Method(p 4-126) N H / (mgA.) 4500D- Std.Method(p 4-80) NOj- (mg/L) NOj- -4500F Std,Method(p 4-91) NO2" (mg/L) NO2" -4500B Std.Method(p 4-87) Tap chi Khi trfgfng Thuy van * Thang 5/2009 Nghidn crfu & Trao doi Qua trinh l i y m l u , bao quan m l u va phan tich chung td nguon nude khdng bj nhilm phen, khdng d i u thye hien khau dam bao c h i t lugng va kiem bj tac dpng bdi nude phen t u vung Ddng Thap Mudi Ben canh dd, pH trung binh tren kenh Nguyen soat chit lugng (QA/QC) X u ly s l lieu b i n g Excel So sanh k i t qua phan tich vdi quy chuin Viet Nam QCVN 08:2008/BTNMT; Chi tieu danh gia v l anh hudng d i n ddi sdng thuy sinh cua Uy Ban Sdng Me Kdng (MRC); Chl tieu danh gia phu dudng ngudn nude cua to chuc Organization for Economic Cooperation Van T i l p B 6,96 nam khoang (6,8 d i n 7,2), t h i p han dang k l so vdi pH tren hai kenh Nha Man T u Tai va C i n Tha Huyen Ham, cd t h i bj anh hudng tryc t i l p bdi vung phen Dong Thap Mudi va chit lugng d i t tren t u y i n kenh Gia trj ehi tieu trung binh DO tren ba tuyen kenh deu kha eao tren 7,2 ppm, cao han quy chuin yeu c l u Cac ch? tieu BOD, and Development (OECD) COD kha t h i p , cao n h i t tren kenh Nguyin Van Tilp Ket qua va thao luan B 3,39 ppm Chi tieu sat tong s l trung binh ca tren a Cac chi tieu pH, nhiet dp, DO, COD, BOD, Fets K i t qua phan tich cho thiy, cac chl tieu pH, nhiet dp, DO, COD, BOD d i u nam gidi han cho phep cua QCVN 08:2008/BTNMT, chCpng td ngudn nude chua bj nhilm b i n huu ca Gia trj trung binh pH cua kenh C i n Tha Huyen Ham 7,35 nam khoang (7,05 - 7,52) tuang duang tren kenh Nha Man Tu Tai 7,36 nam khoang (6,98 -7,71) ba tuyin kenh deu vugt xa quy chuan cho phep, tu trdn 1,8 den tren 18 l l n , cao nhit tren kenh Nguyin Van Tiep B 9,73 ppm, t h i p n h i t tren kenh C i n Tha Huyen Ham 3,77 ppm Sy ed mat mot lugng kha ldn s i t tdng sd nude mat tren kenh Nguyen Van Tilp B so vdi hai kenh khae, da chung td nude kenh bj tae dpng bdi d i t phen tai cho va t u vung Dong Thap Mudi, xem bang Bang Gfa trj trung binh cac ehi tieu pH, nhiet dp, DO, BOD, COD tren eae tuyen kenh Ten k6nh Ckn Thd Huyeu Ham Nha Man Tir T i i Nguyen Van Tie'p B QCVN 08:2008 Gia trj so sanh pH Miu 7,05 Max Nhiet COD Fe (mgA) DO (mg/l) BOD (mg/l) (mgA) 30 8,12 0,670 4,61 1,52 32 10,7 6,52 13,1 6,55 average 7,35 31 9,33 2,71 7,94 3,77 Min 6,98 29 7,64 0,870 3,84 Max 7,71 33 11,3 32,3 average 7,36 31 • 9,30 1,95 9,83 Min 6,80 29 6,80 2,70 5,10 Max 7,20 33 7,50 6,60 average 6,96 31 7,21 3,39 5,91 Al 6-8,5 >6 10 A2 6-8,5 >5 15 Bl 5,5-9 >4 15 30 B2 5,5-9 >2 25 50 1,44 2,15 15,0 6,46 5,67 12,6 9,73 0,5 1,5 b Cae ehi tieu nita ammonium, nita nitrite ngudn nude A l , A2, B l ) ; va ndng dp trung binh ni- Tren kenh Nha Man T u Tai, C i n Tha Huyen Ham trite 0,253 ppm (0,135 - ndng dp trung binh ammonium tuang ung: 0,694 ppm(0,050 - 0,118 ppm), khdng dat yeu c l u c h i t ppm (0,454 - 1,47 ppm); 0,605 ppm (0,338 - 0,772 lugng nude d p loai A l , A2, B l va B2 Ndng dp am- ppm) (vugt tu d i n l l n quy chuan quy djnh eho monium tren kenh Nha Man T u Tai 0,694 ppm va 0,325 ppm); 0,076 Tap chi Khi trfcfng Thuy van * Thang 5/2009 31 Wgmnc^u&rra^W tren kenh Can Tha Huyen Ham 0,605 ppm, dat yeu cho thay chit lugng nude phu hgp vdi quy chuin e l u chit lugng nude loai B2 ( Giao thdng thuy va Viet Nam muc A2 (Dung cho muc dich d p nude cac mue dich khac vdi yeu c l u c h i t lugng nude sinh hoat nhung phai ap dung cdng nghe x u ly phu thip) Cac gia tri trung binh eua chf tieu ammonium hgp; bao ton dpng vat thuy sinh, hoae cac mue dich 0,192 ppm (0,168 - 0,233 ppm), nitrite 0,01 ppm su dung nhu loai B l va B2), xem hlnh (0,005 - 0,030 ppm) tren kenh Nguyin Van Tiep B Hinh Gfa trj min, max, trung binh ammonium (N-NH4+), nitrite (N-N02-) nw&e kenh Ammonium la mdt nhung san pham cd sau thang, s y cd mat cija nitrite d l tao nen Hdi ngudn goc tu phan bdn ndng nghiep, cua qua trinh Chung Tre Xanh (Blue Baby Syndrome) Nitrite k i t khoang hda chit hOu ca, khdng ddc hai cho cae loai hgp vdi huyet c l u to (Hemoglobin) mau tao thuy sinh, nhung la mpt nhCrng phin gdp Methemoglobin, lam giam lugng h u y l t c l u td phin gay nen hien tugng phu dudng ngudn nude va kha nang chuyen chd oxygen cua mau Trong nude gia trj chi tieu ammonium duge xem la tong ammonia, bao gdm ammonium va ammonia Theo FAO, 1987 pH 7,5, d 30°C ammonia ehilm khoang 2,5% ammonia tong so, p h i n tram ammonia tang eao pH tang t u 8,5 d 30°C (20%) d i n 10 d 30''C (khoang 90%) Trong nudi thuy san nong dp ammonia duge khuyin eao nen nhd han 0,1 ppm, nhidn cung cd mdt s l loai ea cd the ehju dung ndng dp ammonia cao han 0,1 ppm Nong dp ammonium, nitrite cao nude tren cae t u y i n kenh khao sat ed the viec s u dung phan hda hpe phue vu tham canh hda, tang vu vung va p h i n Idn cac c h i t thai chua dugc x u ly ' Theo k i t qua khao sat vung cd ba vu san xult/nam: Vu ddng xuan.vu xuan he, vu he thu Nang s u i t vu ddng xuan khoang tIn/Ha/vu, vu xuan he khoang 5,5 tIn/Ha/vu va vu he thu khoang 4,6 tan/Ha/vu L i i u lugng phan bdn dung cho moi Nitrite ed ngudn gdc t u phan bdn, la san pham vu, tren moi loai d i t khac nhau, d hp san x u l t lua trung gian cua qua trinh chuyen hda ammonium gidi, dat nang s u i t cao va thudng dung liiu lugng nitrate (nitrate hda) Trong ca the tre em dudi phan bdn xem Bang Bang Lieu lwang bdn phin eua ngw&i dan Loai phSn Vu D6ng XuSn (kg/ha) Vu He Thu (kg/ha) Ure 210-220 175 - 180 VuThuD6ng (kg/ha) 125 - 150 DAP 90 - 120 90 - 100 60 - 75 40- 50 35- 40 25 - 35 NPK (Ngudn: Phdn vien Quy hoach vd Thiit ki Ndng nghiep Mien Nam, 2007) 32 Tap chi Khi trftfng Thuy van * Thang 5/2009 /? Nghien cu'u & Trao doi Theo khuyin cao cua Vien Lua Ddng Bang Sdng nude mat vugt quy ehuan cho phep nhilu l l n Cuu Long, phan bdn su dung cho vu ddng xuan: Theo k i t qua dieu tra eua chung tdi, d y k i l n d i n 100 - 120 kg N/ha, vu he thu, xuan he la - 0 nam 2010, lugng phan bdn hda hpc d n cho san kg N/ha Nhu vay viec sudung phan bdn hien trang x u l t vung, vdi 23.000 dat ndng nghiep vao da cao han mue khuyin cao, tao sy lang phi va khoang 25.890 t i n cac loai, dd phan Ure gay anh hudng d i n mdi trudng K i t qua phan tich ehilm d i n 48%, xem Bang 3.3 chit lugng nude cung da eho t h i y ham lugng nitrite Bang Dy kiin lwang phan bdn hda hgc siJr dung din nam 2010 Tyl6 Thofi gian cung ifng Tan So' lu'c/ng (TSfn) 12.300,00 0,48 Phan DAP Tan 5.250.00 0,20 Cac thdi d i l m diing nhieu nhat la cac thdng 6,7,8, 11 va 12 Phan NPK Tan 7.740,00 0,30 Super lan Tan 600,00 0,02 Tong cong Tan 25.890,00 1,00 Loai v3t ivl Dvt Phan Ure (Nguon: Vien Thuy Lgi vd Mdi Truang) c Anh hw&ng din thuy sinh va phu dwang (Eu- danh gia eua Uy Ban Sdng Me Cdng da dua mpt trophieation) so gia trj gidi han cho ddi sdng thuy sinh eua luu 1) Anh huang din dai sdng thuy sinh , vyc sdng Me Kdng (MRC), nam 2006 Theo Uy Ban Sdng Me Kdng, 2006, gia trj Nts, Pts nude mat Ca sd d l xem xet mue dp phu dudng cua nguon khdng dugc vugt qua tuang ung 1,7 ppm va 0,13 nude la sd lieu phan tich ham lugng dam va phdt ppm, n l u vugt se anh hudng den ddi sdng thuy nude, duge so sanh vdi eae tieu chuan sinh, xem bang Bang Tieu ehuin ehit lwang nw&e (MRC) Stt Thong s6' Drin vi NO3-N NO2-N Tong N Tong P mg/l mg/l mg/l mg/l f Gia tri giiJi han (MRC) Doi vdi ddi song thuy sinh