Tap chi Khoa hoc Trudng Dai hoc Cdn Tha Tdp 54. So 6B (2018) 120-lii
Tap chi Khoa hoc Trifdng Dai hoc Can Thd
Phan B: Nong nghiep, Thuy san va Cong nghe Sinh hocwebsite: sj.ctu.edu.vn DOL 10.22144/ctu.jvn.2018.m
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PHAN VUNG C H A T LU'ONG NU'OC NUOI TRONG THUY SAN 6 DAM CAU HAI, TINH THITA THifeN - HUE
Trucmg V a n D a n ' ' , N g u y e n T h a n h Luan^, M a c N h u B i n h ' v a Via N g g c Ut^
'Khoa Thuy sdn. Trudng Dai hgc Nong Lam Hue
^Phong thi nghiem trong diem quoc gia ve dong luc hoc song bien - Vien Khoa hgc Thuy Lai Viet Nam
^Khoa Thuy sdn, Trudng Dgi hgc Cdn Tho
Ngudi chiu trdch nhijm vi bdi viit- Vo Thi Hdi Hien (email truongvandanip^huaf edu.vn) Thong tin chung:
Ngdy nhdn bdi- 23/02/2018 Ngdy nhdn bdi sua: 27/04/2018 Ngdy duyit ddng- 30/08/2018 Title:
Zoning aquaculture water quality in Cau Hai lagoon, Thua Thien - Hue province Tir khoa:
Chdt luong nude, ddm Cdu Hai. GIS, noi suy. nuoi trdng thuy sdn, phdn vimg chdt lucnig nude Keywords:
Aquaculture. Cau Hai lagoon, GIS, interpolation, water quality, water quality zoning
ABSTRACT
Zoning of aquaculture water quality in Cau Hai lagoon was conducted by comparing with the national standards (QCVN02-}9:2014/BNNPTNT.
QCVN08-MT:2015/BTNMT. and QCVN38 2011/BTNMT) through the helpofGIS. Temperature, dissolved oxygen (DO), nitrate parameters were suitable to aquaculture activities. One hundred percent ofthe area hadpH values in suitable range for aquaculture in the dry season, whereas only 79.4% was in the rainy season. Salinities were most in suitable range for shrimp culture. The alkalinity was unsuitable for aquaculture in rainy season and dry season was respectively 88.04% and 28 92%. BOD5 levels exceeded the QCVN08-MT-2015/BTNMT standard Phosphate contents were not suitable for aquaculture with 91.13% and 53 57% ofthe areas the rainy season and dry season, respectively Un-ionized ammonia concentrations exceeded the standard, with 41.68% and 36.55% of the areas in rainy season and dry season, respectively The concentrations of total coliform were higher than the standard with 63.33% ofthe areas in rainy season and 44 19% in the dry season
T 6 M TAT
Phdn vimg chdt lugng nude nuoi trdng thuy sdn (NTTS) d dam Cdu Hai duoc Ihi/c hiin bdng cdch so sdnh vai cdc bo tieu chudn (QCVN02- 19-2014/BNNPTNT.QCVN08-MT:20I5/BTNMT,QCVN38:201]/BTNMT) du&i su- ho ti-g cua cong nghe GIS. Cdc yeu td nhiit do, DO. nitrate tkich hop cho hoat dgng NTTS. Gid tri pH phu hap cho hoat dgng NTTS vao mua kho Id 100%di4n tich vd miia mua Id 79,4% diin lich. Dg man hdu het phu hgp di Idy nude nuoi lorn. Do kiem khong phu hgp cho NTTScr mua mua vd miia kho idn luot Id 88.04% vd 28.92%. Hdm lugng SODj VU0 qud tiiu chudn cho phep. Hdm luang phosphate khong phii hgp cho hoat dgng NTTS 91,13% dien tich vdo mua mua vd 53,57% vdo miia klio.
Ham lugng NH3 vuat gidi han cho phep vdi 41,68% diin lich (miia mm) vd 36,55% di^n lich (mua kho) Tong coliform cao hon gidi han cho phep vdi 63.33% diin tich (mua mua) vd 44,19% dien tich (miia kho).
Trich dan- Truong Van Dan, Nguyin Thanh Luan, Mac N h u Binh va Vii Ngoc Ut, 2018. Phan viing ch^
lugng nude nuoi trdng thiiy san d dSm C k Hai, tinh Thira Thien - Hul. Tap chi Khoa hoc Trucng Dai hgc Can Tho. 54(6B): 120-128.
Tgp chi Khoa hpc Trudng Dai hpc Can Tha
1 GIOITHIEU
He thdng dam pha Tam Giang - Cau Hai d tinh Thira Thien - Hue la mgt thiiy vuc nude Ig ven biln dien hinh, cd dien tich gan 22,000 ha, day la he thong dam pha Idn nhat Ddng Nam A (Nguyen Dinh va Pham Thi Dilu My, 2005). He thdng dam pha Tam Giang - Cau Hai ddng mgt vai trd rat quan trgng trong qua trinh dieu hda ddng chay, ngan chan su xam nhap man, ngoai ra nd cdn dugc khai thac de phuc vu giao thdng, du lich, danh bat va nuoi trdng thiiy san (NTTS), Nhin chung, mdi trudng nude Ig ciia dam pha da tao dilu kiln thuan lgi cho su phan bo va phat (nen da dang cua cac smh vat thiiy sinh, mang lai mgt ngudn lgi thiiy san dang kl cho cdng ddng hem 300.000 cu dan sinh sdng ven bd. Hang nam, hang nghin tan hai san, ca, torn cac loai dugc khai thac tren vung dam pha. Nhirng nam gan day, hoat ddng NTTS tren toan qudc ndi chung va d Thira Thiln - Hue ndi rilng dang phat trien manh.
Nam 2016, dien tich nudi tdm cua tinh Thira Thiln - Hue la 2.937 ha, trong dd, dien tich nudi tdm sii dat 2.387 ha do tinh cd lgi the dam pha Tam Giang - Cau Hai (Tdng cue Thiiy san, 2017).
Hien nay, hoat ddng NTTS ven dam Cau Hai dien ra rat manh me. Ben canh nhiing tac ddng tich cue va hieu qua kinh tl mang lai thi hoat ddng NTTS tac ddng khdng he nhd din mdi trudng dac biet la mdi trudng nude. Nude thai tir NTTS dac bilt la nude thai chua qua xii ly xa thang vao dam pha gay d nhilm mdi trudng, mang theo mam benh vao nude dam pha, dl lay lan dich benh sang cac ao nuoi khac.
Van dl lay lan dich benh do khdng xii ly nude thai khi thai ra mdi trudng de lai hau qua nang nl ve mdi ttudng dam pha ciing nhu kinh te cua ngudi dan (Truong Van Dan vd ctv., 2015).
Tdm sii va tdm the dugc nudi pho bien d ven dam Cau Hai, Chat lugng nude cap vao ao nudi tdm sii va tdm chan trdng phai dam bao cac yeu cau nhu, nhiet do (18 - 33''C), pH (7 - 9), DO (> 3,5 mg/L), do man (5 - 35%o), do kilm (60 - 180 mg/L), NH3 (< 0,3 mg/L) theo QCVN 02-19,2014/BNNPTNT (gpi tit la QCVN 02); BOD; (4 mg/L), P-PO4 (0,1 mg/L), tdng coliform (2500 MPN/lOOmL) theo cdt Al, OCVN08-MT:2015/BTNMT (ggi tAt la QCVN 08) cho muc dich bao tdn ddng thuc vat thiiy sinh;
N-NO3 (5 mg/L) theo QCVN3 8 '2011 /BTNMT (ggi tat la QCVN 38).
Trong linh vuc thuy san, hi thdng thdng tin dia ly (GIS) da dugc ling dung ke tu giiia nhung nam 1980. DSu thap ky 90 thi GIS mdi ap dung rdng rai vao nghien ciiru cac viing NTTS, khdng chi dii lieu vl ngudn va vi tri ma cdn ca cac dir lieu ve kinh te thi trudng, xa hdi ciing dugc sii dung trong GIS thdi
Tap 54 So 6B (2018) 120-128
dilm nay (Aguilar-Manjarrez va Ross, 1995), l/ng dung GIS trong khoa hoc thiiy san mang lai kha nang phan tich va bieu dien rat nhilu dir lieu dugc cung cap tu nhieu ngudn khac nhau. Cac dii lieu trong he thdng thdng tin dia \y cd kha nang bieu dien mdi tuong quan giua nhilu yeu td ly, hoa va cac ylu td smh hgc trong mdi tnrdng nuoc. Vi thi, GIS co kha nang hd trg quan ly, lap ra kl hoach, quyet dinh viec phat trien khai thac ciing nhu bao tdn ngudn lgi thiiy san (Meaden va Do, 1996). Vi vay, nghien ciru phan vung chat lugng nude NTTS d dam Cau Hai, tinh Thira Thien - Hue dugc tiin hanh dl quan ly tdt mdi trudng viing dam pha, lam co sd de danh gia chat lugng nude mdt each tdng quat, lam ngudn du lieu dl xay dgng ban do phan viing chat lugng nude, ddng thdi cung cap thdng tin moi trudng cho cdng ddng mdt each don gian, de hilu, true quan va nang cao nhan thiic bao vl radi trudng cho cdng ddng. Tir dd, xay dung nhirng biln phap han che 6 nhiem tir chat thai, hda chat, quan ly viec sit dung nude va phuc vu cho hoat ddng NTTS ciia dia phuang.
2 VAT LIEU VA PHUONG PHAP NGHIAN CUti
2.1 Vat lieu nghien cuu
Nghien ciiu sir dung du lieu khdng gian bao gdm ban do thuy h| d dam Cau Hai, ban do hanh chinh cac xa ven dam Clu Hai vdi h | toa do VN-2000. Dii lieu thugc tinh sir dung trong nghiin cuu la dir li|u ve cac yeu td mdi trudng nude d dam Cau Hai tir ngudn sd lilu so cap.
2.2 Phwcrng phap nghien cuu
Phuong phdp thu, bdo qudn vdphdn lich mdu mdu nuac
Dl tai dugc tiin hanh nghiin ciiu trong miia mua va miia khd nam 2017 tai dam Cau Hai, tinh Thira Thiln - Hue. Cac thdng so mdi trudng can phan tich:
nhiet do, pH. DO, dd man, do kilm, BOD5, NHj, N- NO3, P-PO4, tdng coliform. Tan suat thu mau: 5 dot/nam bao gdm thdi diem miia khd (thang 2, 5), thdi diem miia mua (thang 8, 10, 12), vdi 24 dilm/lan, 2 lan/thang, 10 yeu td/dilm. Dung cu thu mau nude theo dd sau dugc sir dung dl lay mau nude
Viec thu mau dugc tiin hanh dua tren ban dd nin dSm cau Hai vdi 24 dilm khao sat (CH1-CH24).
Dilm thu mau duoc dmh vi toa dd bang may GPS Gannin eTrex Touch 25, My vdi he tga do VN-2000 nham dam bao tinh dai dien va lap lai ciia cac dgt khao sat (Hinh 1)
Sir dung chirc nang dan dudng "go to XY" ciia
GPS dl di den diem can khao sat. Tai radi dilm tien
hanh thu mau nude theo 2 tang: tang mat va tang
Tgp chi Khoa hoc TruangDai hoc Cdn Tha day. MSu nude sau khi do cac yeu td taihiln trudng dugc cho vao chai dung mlu 500 mL d i bao quan.
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Hinh 1: Ban dd thu m l u d dam C^u Hai MSu nude phan tich nhu cau oxy sinh hda (BODs) va tdng coliform (TC) dugc bao quan lanh d nhiet do tir 3-5 oC vdi thdi gian tdi da la 24 gid ddi vdi BOD5 va 1 tuSn ddi vdi TC.
Cac yiu t i nhilt dd, pH, DO, do man duoc do tai hiln tnrdng b^ng may Horiba-U52, Nhat Ban, Do kiim dugc do b^ng test kH, Sera, Diic Yeu td P- PO4 dugc do b^ng may Hanna HI713, Rumani. Y l u td NH3 duoc do bing may Hanna HI700. Y l u td N- NO3 dugc do bang may Hanna HI96728, Y l u to BOD; dugc phan tich trong phdng thi nghilm vdi phuomg phap phan tich theo TCVN 6001:2008.
Tdng coliform duoc phan tich trong phdng thi nghiem vdi phuong phap phan tich theo TCVN 4882:2007.
Casd phdn vung chdt lugng nude cho NTTS Phan viing dien tich mat nude cho NTTS bang each so sanh timg yeu td vdi Quy chuan ky thuat Quoc gia v l CO sd nudi tdm nude Ig - dieu kien bao dam v l sinh thii y, bao ve mdi trudng va an toan thuc ph5m (QCVN 02-19: 2014/BNNPTNT) (Bd Ndng nghiep va Phat t n i n Ndng thdn (NN&PTNT), 2014); Quy chuan ky thuat Quoc gia ve chat luong nude mat (QCVN08-MT:2015/BTNMT) (Bd Tai nguyin va Mdi trudng (TN&MT), 2015); Quy chuan ky thuat Qudc gia ve chat luong nude mat bao v | ddi sdng thiiy sinh (QCVN38:2011/BTNMT) (Bd TN&MT, 2011)
Phuong phdp ldp bdn do chdt lugng nude dua vdo cong nghi GIS
Sau khi da co cac k i t qua nghiin ciiu v l chdt luong nude, ArcCatalog, ArcMap trong phSn m I m ArcGIS 10.3 dugc sir dung d l quan ly va phan tich
Tgp 54, So 6B (2018)- l20-i}i khdng gian. Phuang phap ndi suy trgng sd khoang each ngugc IDW (Inverse Distance Weighted) done sii dung de npi suy kit qua cho toan vijng nghien ciiu, Cdng cu phan loai lai (Reclassify) kit hpp voi cac bd tieu chuSn chat lugng nude cho NTTS dinjc sii dung d l lam c o sd tinh dien tich cac phan viing chdt lugng nude.
Phuang phdp xu ly so lieu
Sd lieu dugc xii ly b^ng phan m I m SPSS v.20.0.
Gia tri trung binh, do lech chuan, bien dpng nhoriS va Idn nhSt d hai mua dugc phan tich b^ng thingK md ta Means. K i i m tra phan phdi chuSn ciia dii li^
vdi phep k i i m tra Kolmogorov-Smimov, So sanhsu sai khac giiJa hai mua d miic y nghia a = 0,05 duoc thuc hiln bdi: k i l m dinh tham sd t hai mau doc IJp {Independent-Samples T Test) ddi vdi dir Hluphan phdi chuSn, kieu dii lieu lien tuc cho cdc yeu tlpH, DO, do man, dd kiim, N-NO3, P-PO4, BODj; kiJm dinh phi tham sd Mann-Whitney U ddi vdi dii Leu khdng tuan theo quy luat phan phdi chuan cho cac y i u td nhiet dp, NH3, tdng coliform.
3 K E T QUA VA T H A O LUAN 3.1 Phan viing ch^t lirgng niro'c NTTS thong qua c^c thong sd nen
3.1.1 Phdn vHngtheoyeu tdnhietdg Nhiet do trung binh miia raua (23,9 ± 0,32°C}
thdp hon mua khd (27,7 ± 0,70''C). Nhin chung, nhiet dp cd xu hudng tang dan tii mua mua den mua kho, dieu nay hoan toan phii hgp vdi quy luat bien ddng nhiet dd theo raiia cua nude ta. Miia mua co lugng nhiet tir biic xa raat trdi giam manh, ket hop vdi lugng mua Idn nen lam cho nen nhiet chung ciia dam Cau Hai thip hon miia khd Qua kilm dinh thong ke nhan thay nhiet dg cd su sai khac giiia cac mua CO y nghia thdng ke{p< 0,05) Kit qua nghien cuu nay ciing phu hgp vdt cac nghiin ciiu ve nhiet dd d dara pha Tam Giang - Cau Hai (Thiia Thien- Hui) (23 - 34''C) (Nguyin Van Hgp vd cfv,, 2007), pha Tara Giang (Thira Thien - Hui) (27,1 - 30,8°C) (Truong Van Dan vd ctv., 2015).
K i t qua phan vimg nhilt dp dugc the hi|n oHinh 2. Nhiet dp biln ddng kha ddng diu giua cac diem thu raau, Nhiet do raiia mua biln ddng qua cac diem tir 23,3 - 24,4''C, miia kho tir 26,7 - 28,6''C, Khi so sanh vdi QCVN 02 thdy ring 100% diln tich 6 khu vuc nghiin cim (KVNC) d hai miia cd nhi?t dp hoan toan phil hgp vdi muc dich d p nude cho nuoi torn (18 - 33''C) (Bd NN&PTNT, 2014).
p chi Khoa lioc Tnrong Dai hoc Cdn Tha Tdp 54 So 6B (2018)- 120-128
Hinh 2: Phan vung nhilt dd, (a) miia mira, (b) miia kho
Phdn vdng theo yeu topH Mua khd tmng binh la 7,98 ± 0,32, biln ddng tir 7,55
Gia tri
trung binh
pH raiia mua thap hon miia khd. Miia raua pH = 7,20 ± 0,45 biin dpng tir 6,51 - 7,91.
- 8,59. Kilm dinh thdng ke cho thay pH giiia cac miia cd su khac bilt cd y nghTa thdng kl (p < 0,05).
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Hinh 3: Phan viing pH, (a) miia mua, (b) miia khd
Phan viing pH theo khdng gian dugc thi hien qua
Hinh 3. Khu vuc gan cac cua sdng Tmdi, sdng Dai Giang cd pH thap hon cac khu vuc khac. Khu vuc g k cua biin Tu Hiin (CH20, CH21) cd pH cao nhdt. So sanh vdi QCVN 02 (pH = 7 - 9) thi miia mua phan di|n tich cd gia tri pH khdng phii hgp cho NTTS (pH < 7) vdi 0,2 ha (chiim 20,6% dien tich d5m) quanh cac diim CH I, CH2, CH3, CHS, CH 17, phan dien tich cdn lai deu thich hgp cho boat ddng NTTS, Miia khd ci5 100% dien tich phu hgp cho NTTS, Vao miia mua, cac diem gan ciia sdng Tmdi va sdng Dai Giang (CHI, 2, 3, 8) va gan ngudn thai nude sinh hoat tir dan cu (CH17) nhan ngudn nuoc nggt Idn vdi hara luong chat hiiu ca cao dd vao, kit hgp vdi dd man d nhiing diem nay Ihap, Do dd, pH d nhirng diem nay thap han so vdi cac vj tri khac trong dam Cau Hai va khdng phii hpp cho NTTS,
Khi so sanh vdi cac ket qua nghien ciru khac d Viet Nam cho thay pH d dara Cau Hai khdng sai khac nhilu vdi dam pha Tam Giang - Cau Hai (5,5
- 9) (Nguyin Van Hgp vd ctv., 2007), dara Thiiy Triiu (Khanh Hda) (7,6 - 8,1) (Le Thi Vinh, 2009) va pha Tam Giang (6,83 - 8,32) (Truong Van Dan
vdctv, 2015).3.1.3 Phdn vimg yeu lo DO
Hara lugng DO miia khd va mua raua tuang duong nhau. Miia khd DO trung binh 6,04 ± 0,999 mg/L, biln dpng tir 4,59 - 8,25 mg/L, Miia raua trung binh 5,37 ± 1,005 rng/L, biin ddng tir 3,95 - 7,56 mg/L. Kilm dinh thdng ke cho thay DO miia khd va miia mua sai khac khdng cd y nghia thdng ke (p > 0,05),
Qua Hinh 4 cho thay, ham lugng DO biin ddng
kha ddng diu giiia cac khu vuc ciia dam Cau Hai va
100% dien tich thich hgp cho hoat ddng NTTS theo
QCVN 02 (DO > 3,5 mg/L), Khu vuc g k cira biin
Tu Hien cd ham lugng DO cao nhat d ca 2 miia. Do
d khu vuc nay tac ddng ciia sdng Idn nen lugng oxy
khuech tan tir khdng khi vao nude nhilu.
Tap chi Khoa hoc Truong Dai hpc Cdn Tha
BAH Dtt PWAM VOHO v e u TO DO miA BWA ff OAM eAu
Tgp 54 So 6B (2018) 120-!2i
Hinh 4: Phan viing D O , (a) miia mira, (b) miia kho Ham lugng DO d d i m Cku Hai kha tuong duong
so vdi nghien ciiu DO d dam pha Tam Giang - Cau Hai ciia du an IMOLA (5,1-9,1 mg/L) (Nguyen Van Hgp vd ctv., 2007) va d§m Thuy Triiu (4,8-7,4 mg/L) (Le Thi Vinh, 2009) va pha Tam Giang (4,68- 7,95 rag/L) (Truong Van Dan va ctv., 2015).
3.1.4 Phdn vung yeu to do man
Do man miia khd cao hon miia mua. Do man miia khd biin ddng tir 10,5 - 2 8 , 6 ppt, tmng binh 16,8 ± 6,20 ppt, Miia mua biin ddng ni 3,7 - 20,1 ppt, tmng binh 10,3 ± 5,48 ppt. Dd lich chuSn ciia do man kha Idn la do mirc bien ddng do man kha Idn giua cac diim thu raau, Kilm dinh thdng ke cho thay do man miia khd cao hon miia mua cd y nghia thdng ke vdi p < 0,05.
Phan vimg do man theo khdng gian dam Cau Hai duoc minh hga qua Hinh 5, Nhin chung, dd man c6 su tang dan tir khu vuc quanh cira sdng Tmdi, Dai Giang d i n quanh ciia biln Tu Hiln. Mua mua, khu vuc quanh ciia sdng Tmdi va Dai Giang (quanh d i i m CH2) cd do man thap dudi 5 ppt vdi 585,16 ha chiim 5,22%, cdn cac khu vuc khac deu cd do man trin 5 ppt. Mua khd, do man d tat ca khu vuc d5m CSu Hai d i u Idn hon 5 ppt So sanh vdi QCVN 02 thi dp man phii hgp nudi tdm tir 5 - 35 ppt. Nhu vay, dd man ciia dkm C i u Hai phii hop d i idy nude nuoi tdm, ngoai trir phdn diln tich quanh diem CH2 vao miia mua.
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Hinh 5: P h i n viing do man, K i t qua nghien ciiu phu hgp vdi kit qua da cdng bd v l dd man dam pha Tara Giang - Cau Hai la 0 - 35 ppt (Nguyen Van Hpp va ctv., 2007) va cao hon so vdi pha Tam Giang (0,8 - 26,0 p p t ) (Truang Van Dan va c t v , 2015).
3.1.5 Phdn vimg yeu to do kiem
Dp kilm trung binh miia khd la 67,6 ± 19,04 mg/L, bien ddng tir 44,8 - 107,4 mg/L Miia mua
(a) miia m u a , (b) miia khd
trung bmh 48,3 ± 22,45 mg/L, b i l n ddng tit 17,9 - 89,5 mg/L, Nhu vay, chenh lech dd k i l m ciing kha Idn giiia cac d i l m thu mau. Dilu nay do dp man chinh lech kha Idn giira cac diem. Do k i l m miia kho va mua mua sai khac khdng cd y nghia thdng ke (p
> 0,05). K i t qua nghiin ciiu dp k i l m d dara Cau Hai kha tuang ddng vdi do kilm d pha Tam Giang (35,8 - 89,5 mg/L) (Truang Van Dan vd ctv., 2015).
I Tap chi Khoa hoc Trudng Dgi hoc Can Tha
BAN M n U N VUNO Y E U TO DO KlCtl H O A y VA 0 D A N CAU w
Tap 54 So 6B (2018): 120-128
BAN DO P H A H VUNO r e u TfiOOKItM I | 0 A K H 6 O O A H CAUHAI
Hinh 6: Phan viing dd kiim, (a) mua mira, (b) miia kho Phan vimg do k i l m cho hoat ddng NTTS d dam
Cau Hai dugc the h i | n qua Hinh 6. Miia mua, do kiim quanh cac d i i m CH13, CH19-22 cao tren 60 mg/L vdi chi 1339,3 ha chiim 11,96% Phin dien tich cdn lai vdi 9.860,67 ha chiim 88,04% cd dd kilm dudi 60 mg/L, khong thich hop cho lay nude nudi tdm khi so sanh vdi QCVN 02 (60 - 180 mg/L).
Miia khd, dg kiim quanh cac diim C H l - 7 va CHIO thdp dudi 60 mg/L vdi 3239,11 ha chiim 28,92%, khdng thich hgp cho lay nude nudi tdm theo QCVN 02, phan d i | n tich cdn lai deu tren 60 mg/L, N h u vEiy, quy luat bien ddng dp k i l m phii hgp vdi su thay ddi do man theo khdng gian d pha Tam Giang.
IN OO P H A N VtlNO T G U ra SOD UUA MITA O DAH CAu
3.2 Phan viing chat lirgng nude NTTS thong qua cac thdng sh hiru co*
3.2.1 Phdn vung yiu to BOD5
Ham lugng BOD5 mua mua bien dgng tu 4,95 - 9,67 mg/L, trung bmh 7,01 ± 1,687 mg/L. Mua khd, BOD5 biin dgng tir 3,8 - 7,91 mg/L, trung binh 5,58
± 1,556 mg/L, Kilm dinh thdng ke cho thay B O D ; d 2 mua cd su sai khac cd y nghia thdng k l vdi p <
0,05. Khi so sanh vdi QCVN 08 thi ham lugng BOD; da vugt ngudng cho phep cho hoat ddng NTTS d ca 2 miia (4 mg/L), Ham lugng BOD5 ciia nghien ciiu nay cao hon so vdi nghien ciiu d dam pha Tam Giang - Cau Hai (0,5 - 5 mg/L) (Nguyen Van Hgp v(ic(v, 2007),
T C U 1 0 BOO H O A K H O O O A H CAU HAI
Hinh 7: Phan vung BODS, (a) miia mua, (b) mua kho Phan viing BOD; theo miia dugc t h i hien qua
Hinh 7. Hau hit phan dien tich dam Cau Hai cd ham lugng BOD; vugt qua tilu chuan cho phep khi so sanh vdi QCVN 08 (4 mg/L), ngoai trir phan diln tich 131,46 ha chiim 1,17% giiia diim CH14 va CHI5 vao miia khd, N h u vay, ngudi dan can lim y xir ly ky cac chat huu co trudc khi lay nude vao ao nudi.
3.2.2 Phdn viingyeu to N-NO3
Ham lugng nitrate miia mua cao hon miia khd vdi ham lugng trung binh Ian lugt la 0,32 ± 0 , 1 0 6 mg/L va 0,22 ± 0 , 1 0 2 mg/L. Mua mua, nitrate biin dgng tir 0,17 - 0,42 mg/L. Miia khd, nitrate biin ddng tir 0,08 - 0,33 mg/L Ham luong nitrat miia mua cao hon miia khd la do miia mua cd su xdi radn, nia trdi cac viing dat ven bd vao dara pha Idn han.
Tap chi Khoa hoc Trudng Dai hoc Cdn Tha cdng vdi SU ddng gdp chat hihi co tit cac kinh nude thai vao dara pha lam tang cac ngudn co chat de tao N03', ngudn ca ciiat nay se dugc cac vi khuan hda tu dudng {Nilrospina. Nitrosococcus) nitrat hoa de tao ra NO3". Ddng thdi nitrat ciing duoc bd sung tir nude mua khi cd sam chdp. Do thanh phan khdng khi chil yeu va nito va oxy, Q dieu kien thudng thi chiing khong phan ling vdi nhau, nhung khi cd sam chdp (tia Ilia dien) thi chung lai phan ling tao ra khi NO. Khi NO tiep tuc bi oxy hda d l tao ra khi NO2.
Khi NO2 hda tan Irong nude mua tao ra HNO3 va rai xudng dam pha, HNO3 tac dung vdi cac chat cd
BAN DO P H A H VUNO YGU TO NITIUTE HUA HUA aOAH CAU M l
Tgp 54 Sd 6B (2018): 120-128 trong nude dam pha nhu CaCOj, MgCOj, NH3... d^
tao ra NOs'. Kilm dinh thdng k l cho thay nitrate khdng sai khac giiia cac miia vdi p > 0,05. Ham luong nitrate d dam Cau Hai cao hon so vdi cac dSm pha Tam Giang - Cau Hai (0,05 - 0,26 mg/L) (Nguyen Van Hpp vd cfv., 2007), dSm Thuy TriSu (0,04 - 0,15 mg/L) (LI Thi Vinh, 2009). Theo QCVN 38 thi ham lugng nitrate thich hgp cho nuoi tdm ca la 5 mg/L. Nhu vay, ham lugng nitrate d dim Cau Hai vSn thSp hon rat nhilu so vdi gidi han cho phep.
BAN 0 0 P H A N V U H O Y E U TO NITRATE HUA K H O O O A M CAU HAI
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Hinh 8: Phan viing N - N 0 3 , (a) mua m u a , (b) mua kho Phan vimg ylu td nitrate dugc minh hoa qua
Hinh 8. Ham lugng nitrate cao d khu vuc ciia sdng, gan khu NTTS va nai tiep nhan nude thai tir hoat ddng sinh hoat ciia ngu dan ven ddm. Tuy nhiin, 100% dien tich dam d ca 2 miia vln n^m dudi ngudng cho phep va deu thich hgp d i idy nude cho NTTS,
3 2.3 Phdn vimg yiu td P-PO4
Ham lugng phosphate trung binli mua mua la 0,17 ± 0,086 mg/L, biin ddng tir 0,08 - 0,33 mg/L, Miia khd, ham luong phosphate trung binh la 0,12 ± 0,086 mg/L, biin dpng tir 0,02 - 0,27 mg/L, Kiim dinh thing ke cho thdy ham lugng phosphate miia mua va miia khd sai khac khdng co y nghTa thing k l (p > 0,05), Ham luong phosphate d ddm Cau Hai cao hon so vdi cac ddra pha Tam Giang - Cdu Hai (0,01 - 0,1 mg/L) (Nguyen Van Hop va ctv , 2007), ddm Thiiy T n i u (0,004 - 0,026 mg/L) (Le Thi Vinh 2009), Theo QCVN OS thi ham lugng cho phep ddi vdi hoat dgng NTTS la 0,1 mg/L Nhu vay, ham
lugng phosphate trung binh d ca 2 miia diu da vuat ngudng cho phep va nguy co phii dudng rdt cao a dam Cau Hai.
Kit qua phan viing yeu td phosphate dugc th^
hien qua Hinh 9, Miia raua, ham lugng phosphate phil hop vdi idy nude NTTS chiim dien tich rat nho quanh cac diim CH14 - 17 vdi 993,38 ha chiim 8,87%, i^hdn dien tich cdn lai (91,13%) khong phu ligp d l idy nude nudi tdm va d l gay tinh trang phu dudng, dac biet cac khu vuc gdn cira sdng Tmii, cira sdng Dai Giang ( C H l - 8 , CHIO), khu vuc quanh dilm CH21, CH23 cd ham luong phosphate cao tii 0,21 - 0,33 rag/L (chiim 37,2% diln tich). Miia kho, phan diln tich phu hgp idy nude NTTS chiSm 46,43% dien tich, quanh cac diim CH9-20, CH24, phan dien tich cdn lai (53,57%) khdng phii hgp cho lay nude NTTS, dac bilt quanh khu vuc ngufln thai tir hoat ddng NTTS (CH6-7) cd ham luong phosphate cao tir 0,201 - 0,269 mg/L (chiim 6,36%
diln tich).
p chiKhog hoc Trudng Dgi hoc Cdn Tha
BAN DO P K A H V U H O T G U TO PHOSPHATE HI>AHl/A tl OAU CAU HI
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Hinh 9: P h a n viing P-PO:i, (a) miia mira, (b) m u a kho
vdi QCVN 02 thi hara lugng NHj d ddm Cdu Hai 3.3 PhSn vung chat l u g n g nurd-c N T T S
thong qua thdng so khi doc va vi sinh 3.3.1 Phdn -vung yeu to NHj
Ham lugng NHj miia khd trung binh la 0,224 mg/L, bien dgng tii 0,036 - 0,633 mg/L. Miia mua trung binh 0,306 mg/L, b i i n ddng tu 0,085 - 0,700 mg/L, Kiera dinh thdng k l cho thay NH3 sai khac khdng c6 y nghia giira 2 mua (p > 0,05). Khi so sanh
U N D O PHAH VONO ycu TO NHJ HOA MUA ODAH CAU HAI
tiem can vdi gidi ban cho phep (0,3 rag/L).
Ham lugng amoniac d dam Cau Hai cao han so vdi cac dam pha Tam Giang - Cau Hai (0,02-0,14 rag/L) (Nguyin Van Hgp va ctv., 2007), dam Thuy Triiu (0-0,084 mg/L) (Le Thi Vmh, 2009) va pha Tam Giang (0,004-0,127 mg/L) (Truong Van Dan va ctv., 2015),
BAN DO P H A N V O H O Y E U TO NH3 Hlto KHOO D A H CAU H A I
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Hinh IO:Phan viing NHi, (a) miia mu^, (b) miia kho Phan vimg NH3 theo khdng gian dugc minh hga
qua Hinh 10. Ham luong NH3 cao vugt gidi han cho phep chii y l u quanh ciia sdng Trudi, sdng Dai Giang va gdn khu NTTS tap trung (CHI - 8) vdi 41,68%
diln tich (raua mua) va 36,55% dien tich (mua khd).
Dac bilt, ham lugng NH3 d khu vuc quanh cac dilm CH2, 3, 6, 7 cao trin 0,5 mg/L vdi ty II 21,3% diln tich (miia mua) va 10,37% diln tich (mua khd) Ham lugng NH3 phii hgp cho NTTS d dam Cau Hai chiim 58,32% diln tich (miia mira) va 63,45%i dien tich (miia khd) quanh cac diem CH9 - 24.
3.3.2 Phdn vimg yiu to tong coliform Mat dg tdng coliform trung binh miia mua la 3533±2581 MPN/100 mL, biin dgng tir 780 - 8167 MPN/IOO mL. Miia khd, mat dd tdng coliform trung binh la 2979±2395 MPN/160 mL, biin dgng til 575
- 6850 MPN/IOO mL. So sanh vdi QCVN 08 cho thay mat dd tdng coliform trung binh da vugt qua gidi han cho phep va cd su nhiem khuan cue bd d mdt vai khu vuc d dam Cau Hai.
Kit qua phan viing tdng coliform theo khdng gian duoc the hien qua Hinh 11. Miia mua, mat dp tdng coliforra cao han gidi ban cho phep d quardi khu vuc cua sdng Tmdi, sdng Dai Giang (CH2 - 3), khu NTTS (CHI, 4 - 13), gdn khu dan cu (CH18 - 19, 22 - 24) vdi 63,33% dien tich, phan diln tich cdn lai phil hpp cho NTTS. Mua khd, phan diln tich co tdng coliforra cao hon gidi han cho phep tap trung quanh khu vuc cira sdng Tmdi, sdng Dai Giang (CH2 - 3), khu NTTS (CHI, 4 - 12) voi diln tich 44,19%.
Tup chi Khoa lioc Trmmg Dai line Can Tho Tap 54. Sd 6B (2018) I2(i.!2i
Hinh 11: Phan viing tong coliform, (a) mua mira, (b) miia kho t KETLUAN
Chat luong nude d dam Ciiu Hai vao miia khd lot hon miia mua. Vao raiia khd, khi lay nude cho NTTS can chu y den cac ylu td vugt qua gidi han cho phep nliu dp kiem (thap o quanh cac diem CH 1 - 7, 10), BOD5 (cao o toan dam, ngoai trir phan dien tich rdt nhd giua diim CHI4 va CHI5), P-PO4 (quanh cac dilm CH 1 - 8, 21 - 23), NHi (quanh cira sdng Trudi, sdng Dai Giang va gan khu NTTS (CH I - 8)), tong coliform (quanh cira song Trudi, song Dai Giang ( C H 2 - 3 ) , khu NTTS (CHI - 4 , 12) Vao miia mua. can luu y den cac yeu td v uot nguong cho phep de lay nude cho NTTS nhu pH (thap d gan cua sdng Truoi, song Dai Giang va nude thai khu dan cir (CHI - 3, 8. 17), do man (thdp d quanli diem CH2), do kiem (thap d quanh cacdicm CHI - 12, 1 4 - 18.
23 - 24), BOD5 (cao d toan ddm), P-PO4 (rdt cao d cac khu vuc gan cua song Tnidi, ciia sdng Dai Giang (CHI - 8, CHIO), khu vuc quanh diem CH21.
CH23)), NHj (cao a quanh cua sdng Tmdi, sdng Dai Giang va gan khu NTTS tap trung (CH 1 - 8)), t i n g colifonn (quanh khu vuc ciia sdng Trudi. song Dai Giang (CH2 - 3), khu NTTS (CHI, 4 - 1 3 ) . gdn khu dan c u ( C H 1 8 - 1 9 , 2 2 - 2 4 ) )
TAI LIEU THAM KHAO Aguilar-Manjarrcz, J and Ross. L G , !995
Geographic intbrmation system GIS enviionmenial models for aquaculture development in Smaloa Sate, Mexico Aquaculture Inlemaiional, 3(2): 103-115 Bo NN&PTNT, 2014 QCVN 02-19
2014/BNNPTNT, ngay 29/07/2014, Quy chudn ky ihual quoc gia ve co so nuoi torn nirdc lo - (lieu kien bao dam ve sinh thii y, bao ve moi truang va an loan thuc pham
Bo TN&MT, 2011, QCVN 38 201 l/BTNMT.jii 12/12/2011, Quy chuan ky thuat quoc gia vel lucmg nirdc mai bao ve doi song thiiy sinh Bo TN&MT. 2015 QCVN 08-MT 2015/BTNM1
ngay 21/12/2015, Quy chuan ky thuat quoc gia ve ell at luong niro'c mat
Le Thi Vmh, 2009 Chai lircmg nude moi tnrongi Thiiy Trieu - Khanh Hoa. Tap chi Khoa hpc Cong nghe biin, 9(1) 34-45, Meaden, G J and Do, T C , 1996. Geographical
infonnation Applications to manne fisheries:;
applications to machine fisheries FAO Fishril Technical Paper. 356: 335p
Nguyen Van Hop, Trucmg Quy Tiing, Hoang Long vd ctv , 2007 Danh gia chat luong nudi trSm tich dam pha Tam Giang - Cau Hai 200{
2007 Dir an IMOLA Hue
Nguyen Dinh va Pham Thi Dieu My, 2005 Tong quan nhiing nghien ciiu ve dam pha tam Giap Cau Hai, nhirng van de con ton tai can khac p de huong idi quan ly va khai ihac ben vimg.
Tiong So Khoa hoc va Cong nghe tinh Thira Thicn - Hue Ky yeu hoi thao quoc gia ve dai pha Thua Thien - Hue Hoi thao quoc gia ve >
pha Thua Thien - Hui. ngay 23-24/12/2005, thanh phi Hue 65 77
Tong cue Thiiy san 2017 Oiai phap phit tnen m trong thiiy san btn \uniz tai cae linh mien Tn tmy cap ngay 22 n2 2"l'- F'' -1 1 https//tongcuelhii i VoB4i tr%EI%BB"o91ii I I I "\
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2015 Ung dung hi. Ihong thong Un dia 1> (Gia phan vimg chat luong nuoc nuoi trong ihiiy sanl pha Tam Giang, linh Thira Thien - Hue Tap c||
khoa hoc Dai hoc Hui. 104(5) 67-78
