129

TP CH KHOA HC, i hc Hu, S 57, 2010

S DNG NG VT KHNG XNG SNG C LN NH GI CHT LNG MI TRNG NC MT S IM TRN SNG B,

TNH THA THIN HU

V Vn Ph, Hong nh Trung, L Mai Hong Thy Trng i hc Khoa hc, i hc Hu

TM TT

Trong cng tc qun l, gim st v quan trc mi trng nc hin nay, vic nh gi

cht lng nc thng qua phng php phn tch cc ch tiu l ha ang c s dng rng

ri. Tuy nhin, cc phng php ny c mt s hn ch nht nh. y l phng php gin

tip ch c th phn nh tnh trng thy vc ngay ti thi im ly mu, kh c th d bo chnh

xc v cc tc ng lu di ca chng n khu h sinh vt nc. Bn cnh , vic phn tch

ho l phi c thc hin lin tc vi tn sut ln s gy nhiu tn km v kinh t. Tri li,

phng php quan trc sinh hc khc phc c mt s hn ch ca phng php trn nh

cung cp cc dn liu v thi gian, tin li trong s dng v cho kt qu nhanh, trc tip v nh

hng ca hin trng nhim n s pht trin ca h thng thy sinh vt.

Trong nghin cu ny, chng ti tin hnh s dng thnh phn ng vt khng xng

sng (VKXS) c ln sng B, tnh Tha Thin Hu, lm ch th sinh hc nh gi cht

lng nc mt ti 07 im trn sng thng qua h thng tnh im BMWPViet v ch s sinh hc

ASPT. Kt qu phn tch mu vt VKXS c ln thu c t thng II/2008 n thng VII/2008

xc nh c 44 h VKXS c ln bao gm: 28 h thuc 2 lp ca ngnh Chn khp

(Arthropoda), 15 h thuc 2 lp ca ngnh Thn mm (Mollusca), 1 h thuc lp a v mt s

i din ca lp Giun t t, Giun nhiu t ca ngnh Giun t (Annelida). Trong , c 37 h

tham gia vo h thng tnh im BMWPViet; nghin cu cho thy cht lng mi trng nc mt

ti y b nhim t mc nc bn va (-Mesosaprobe) n nc bn va (-

Mesosaprobe). Kt qu ny ph hp vi vic nh gi cht lng nc mt thng qua phn tch

cc ch tiu ho hc, m nhm nghin cu chng ti thc hin trc (2007).

1. M u

Sng B l ph lu cp mt ca h thng sng Hng, bt ngun t dy Trng Sn ng v vng ni pha Ty Nam huyn A Li, chy qua ba huyn Hng Tr, Phong in v Qung in, vo sng Hng ng ba Snh, cch trung tm Hu 8km v pha Bc. Sng B c mi quan h rt mt thit n i sng ca ngi dn. y chnh l ngun cung cp nc sinh hot v sn xut trong khu vc. Theo , cht

130

lng nc cng nh ngun ti nguyn sinh vt ca h sinh thi sng B rt cn c nghin cu v nh gi kp thi. Vit Nam, vn gim st sinh hc cht lng nc ngt c cp t nhiu trong 10 nm tr li y. Tuy nhin n nm 2000, khi Nguyn Xun Qunh v cng s xy dng h thng tnh im BMWPViet v kha nh loi n h cc nhm VKXS c ln nc ngt thng gp (Nguyn Xun Qunh, 2001, 2004) th mi bt u thi k ng dng rng ri quy trnh gim st cht lng nc cc thy vc nc ngt Vit Nam. Hin nay cha c nhng tiu chun sinh hc c th hay cc ch s sinh hc nh gi cht lng ngun nc mt. Cn phi c nhng nghin cu trn nhiu khu vc xy dng mt h thng ch s sinh hc dng nh gi cht lng nc ph hp cho tng vng.

Trn c s thc tin ca vn , chng ti tin hnh kho st, nh loi thnh phn VKXS c ln sng B, tnh Tha Thin Hu nhm bc u gp phn xy dng h thng ch th sinh hc nh gi cht lng nc mt Tha Thin Hu vi mc ch bo v a dng sinh hc ni chung v lm c s cho vic nh gi cht lng nc vng nghin cu.

2. i tng v phng php nghin cu

2.1. i tng

i tng nghin cu l thnh phn loi VKXS c ln sng B, tnh Tha Thin Hu. Qu trnh nghin cu c thc hin trn dng chnh ca sng B, t p thy in Hng in n ng ba Snh, tng ng vi 7 im ly mu. Cc mt ct v im ly mu c la chn sao cho c th thu c cc i din cho vng ly mu v tun th ng theo quy trnh, quy phm iu tra c bn ca UBKHKT, nay l B KH&CN ban hnh 1981.

Bng 1. V tr cc im thu mu trn sng B, tnh Tha Thin Hu

Stt a im thu mu K hiu Ghi ch

1 p thu in Hng in M1 Hng Vn, Hng Tr; Phong Sn, Phong in

2 Cu Hin S M2 Hng Vn, Hng Tr; Phong Sn, Phong in

3 Cu An L M3 Phong An, Phong in

4 Ph c M4 T H, Hng Tr; Qung Ph, Qung in

5 Ch H Lan M5 Qung Ph, Qung in; Vn X, Hng Vn

6 Qung Th M6 Qung Th, Qung in

7 Ng ba Snh M7 Qung Phc, Qung in

131

Hnh 1. S cc im thu mu trn sng B

2.2. Phng php nghin cu

Hnh 2. M hnh nghin cu

2.2.1. Phng thu mu ngoi thc a

- Mu VKXS c ln c thu bng vt ao (pond net), vt tay (hand net) v gu y Petersen, quy trnh thu mu thc a tun theo phng php ca Nguyn Xun Qunh, Clive Pinder, Steve Tilling v Mai nh Yn (2002). Cc mu c c nh trong formol 4% ngay sau khi thu mu, nhm ngn nga cc loi n tht c trong mu khng n cc sinh vt khc v trnh b thi ra.

Kho st thnh phn v s lng VKXS c ln

Phn tch cc ch tiu mi trng nc mt

nh gi mi tng quan gia cc ch tiu mi trng nc mt v VKXS c ln

nh gi cht lng nc bng ch s ASPT

132

- Ly mu nc: Song song vi vic thu mu VKXS c ln, chng ti cn tin hnh kho st mt s thng s mi trng nc theo phng php ly mu v bo qun ca TCVN 5993 - 1995 [1], [5] v [6].

2.2.2. Phng php phn tch mu trong phng th nghim

- Mu VKXS c ln sau khi thu v c phn tch thnh cc phenon, nh m s v chuyn sang bo qun trong cn 700. Sau tin hnh nh loi hnh thi theo cc kha nh loi lng phn ca Nguyn Xun Qunh, Clive Pinder, Steve Tilling (2001); ng Ngc Thanh, Thi Trn Bi, Phm Vn Min (1980) v mt s ti liu chuyn ngnh ngoi nc dng trong ch th mi trng nc [2], [3], [4], [7], [8]. Tt c vt mu sau khi nh loi, c lu gi phng th nghim Ti nguyn - Mi trng, Khoa Sinh hc, Trng i hc Khoa hc, i hc Hu.

2.2.3. Phng php s dng h thng tnh im BMWPViet v ch s ASPT

Ch s ASPT (Average Scores Per Taxon) l phng php s dng h thng tnh im quan trc ca tng im s ca cc h VKXS c ln bt gp. Mu thu thp c phn loi, nh danh n taxon bc h. S dng h thng thang im BMWPViet (Biological Monitoring Working Party, 2004) cho iu kin Vit Nam.

Bng 2. Mi lin quan gia ch s sinh hc (ASPT) v mc nhim

Th hng Ch s sinh hc ASPT Mc nhim

I 10 - 8 Khng nhim, nc sch

II 7,9 6,0 Nc bn t (Oligosaprobe), hay tng i sch

III 5,9 5,0 Nc bn va ( - Mesosaprobe)

IV 4,9 3,0 Nc bn va ( - Mesosaprobe) hay kh bn

V 2,9 1,0 Nc rt bn (Polysaprobe)

VI 0 Nc cc k bn (khng c VKXS c ln)

(Ngun: Environmental Agency, UK, 1997)

Ch s ASPT nm trong khong t 1 - 10. Ch s cng thp nc c nhim cng cao. Da vo ch s ASPT nh gi cht lng mi trng nc ca tng im nghin cu theo bng phn loi (bng 2).

N: tng s h tham gia tnh im; BMWP: tng im s BMWP;

ASPT: ch s trung bnh trn taxon

133

3. Kt qu nghin cu

3.1. Kt qu kho st v thnh phn VKXS c ln sng B

Qua kt qu 6 t kho st ti 7 im trn sng B, chng ti ghi nhn c 44 h VKXS c ln. i vi ngnh Giun t (Annelida) c 3 lp: lp a (Hirudinea), lp Giun t t (Olygochaeta) v lp Giun nhiu t (Polychaeta). Do iu kin ti liu cha y nn cha th tin hnh nh loi n h, v vy, nu mi lp Giun t t v Giun nhiu t c t nht 1 h th tng s h ca hai lp s l 2 h. Nh vy, ngnh Giun t c 3 h nm trong 3 lp c mt ti sng B. Trong ngnh Thn mm (Mollusca), chng ti xc nh c 15 h thuc hai lp Chn bng (Gastropoda) v Hai mnh v (Bivalvia). Ngnh Chn khp (Arthropoda) bao gm 28 h thuc 8 b ca 2 lp Gip xc (Crustacea) v lp Cn trng (Insecta).

15

3

28

Thn mm Chn khp Giun t

Hnh 3. S lng cc h thuc cc ngnh VKXS c ln sng B

Bng 3. Danh lc cc h VKXS c ln c mt ti cc im thu mu trn sng B

Stt Tn khoa hc Cc im nghin cu

im

BMWP Viet

1 2 3 4 5 6 7

Ngnh Giun t - ANNELIDA

Hirudinea

1 Glossiphonidae + 3

2 Olygochaeta + + + + 1

3 Polychaeta * + +

Ngnh Thn mm - MOLLUSCA

Gastropoda

4 Fairbankiidae * + + + + + + +

5 Pachychilidae * +

6 Thiaridae + + + + 3

134

7 Pilidae + + + + 4

8 Littorinidae * +

9 Viviparidae + + + + + 4

10 Assimineidea * + + +

11 Littoridinidae + + + 3

12 Planorbidae + + 3

13 Lymnaeidae + + 3

Bivalvia

14 Unionidae + 4

15 Mytilidae + + + + 5

16 Amblemidae * + +

17 Pisidiidae + + + 3

18 Corbiculidae + + + + + + + 3

Ngnh Chn khp -ARTHROPODA

Crustacea

Amphipoda

19 Oedicerotidae * + +

20 Hyalidae * + +

Decapoda

21 Palaemonidae + + + + + 3

22 Atyidae + + + + + + + 3

23 Parathelphusidae + + 3

24 Potamidae + 8

Insecta

Diptera

25 Tipulidae + 5

26 Chironomidae + + + + 2

Hemiptera

135

27 Gerridae + + 5

28 Hydrometridae * + + + + +

29 Corixidae + + 5

30 Pleidae + 5

31 Belostomatidae + 5

Coleoptera

32 Hydrophilidae + + 5

33 Curculionidae + 5

34 Ptilodactiliidae + 5

Ephemeroptera

35 Potamanthidae + 10

36 Baetidae + 4

37 Ephemeridae + + 10

Trichoptera

38 Polycentropodidae + 7

Odonata

39 Macromidae + 6

40 Platycnemidae + 6

41 Lestidae + + + + + 6

42 Calopterygidae + + + + 6

43 Libellulidae + 4

44 Gomphidae + + + + + + 6

45 Aeshnidae + + + 6

46 Coenagrionidae + + + + + 4

Cng 17 15 11 19 18 19 27

Ghi ch: (+) S c mt ti cc im nghin cu ca cc h VKXS c ln

(*) C mt nhng khng c trong bng tnh im BMWPViet

Thnh phn v mt ca cc h VKXS c ln sng B l khng ging nhau gia cc im nghin cu (t M1 n M7) v nh cao v s h thng tp trung

136

ng ba Snh (M7), vi 27 h. y l vng a sinh cnh ko theo a dng v thnh phn taxon bc h ca cc lp VKXS c ln. Do c trng dng chy v cht lng nc khng ging nhau ti cc im nghin cu nn thnh phn v mt bt gp cc h VKXS c ln tng im cng khc nhau. Cao nht l ti ng ba Snh (M7) vi 27 h v thp nht l ti cu An L (M3) vi 11 h. Mt s h c phm vi phn b rt hp, ch bt gp ti mt im nghin cu v vi mt khng cao nh h Glossiphonidae thuc lp a (Hirudinea) ch xut hin vng nc ven b sng ch H Lan (M5), h Potamanthidae thuc b Ph du (Ephemeroptera). Bn cnh , c mt s h c phm vi phn b rt rng, in hnh l h Fairbankiidae thuc lp Chn bng (Gastropoda) c mt trn tt c cc im nghin cu vi mt rt cao (bng 3).

3.2. nh gi cht lng nc da trn VKXS c ln

T cc ch s sinh hc ASPT thu c kt hp vi Mi lin quan gia ch s sinh hc v mc nhim (bng 2), chng ti c c mc nhim tng ng ca cc im nghin cu qua cc t kho st (bng 4).

Bng 4. Ch s ASPT v mc nhim ti cc im qua thi gian nghin cu

im

nghin

cu

Theo h thng BMWPViet

Thng

II/2008

Thng

III/2008

Thng

IV/2008

Thng

V/2008 Thng VI/2008

Thng

VII/2008

ASPT

Mc

nhim

bn

ASPT

Mc

nhim

bn

ASPT

Mc

nhim

bn

ASPT

Mc

nhim

bn

ASPT

Mc

nhim

bn

ASPT

Mc

nhim

bn

M1 5,2 Bn

va () 5,3

Bn va

() 5,1

Bn

va () 5,3

Bn va

() 5,2

Bn

va () 5,0

Bn va

()

M2 4,3 Bn

va () 4,4

Bn va

() 4,1

Bn

va () 4,4

Bn va

() 4,3

Bn

va () 4,2

Bn va

()

M3 4,4 Bn

va () 4,7

Bn va

() 4,2

Bn

va () 4,8

Bn va

() 4,5

Bn

va () 4,4

Bn va

()

M4 4,6 Bn

va () 4,9

Bn va

() 4,4

Bn

va () 4,1

Bn va

() 4,3

Bn

va () 4,2

Bn va

()

M5 3,4 Bn

va () 3,4

Bn va

() 3,2

Bn

va () 3,3

Bn va

() 3,2

Bn

va () 3,1

Bn va

()

M6 4,0 Bn

va () 4,2

Bn va

() 4,2

Bn

va () 4,4

Bn va

() 4,2

Bn

va () 4,0

Bn va

()

M7 4,3 Bn

va () 4,0

Bn va

() 3,8

Bn

va () 4,4

Bn va

() 4,4

Bn

va () 4,1

Bn va

()

137

Bng 5. Cht lng nc ti cc im sng B qua thi gian nghin cu

im

nghin

cu

Cc ch tiu ha hc

Thng

II/2007

Thng

III/2007

Thng

IV/2007

Thng

V/2007

Thng

VI/2007

Thng

VII/2007

COD

(mg/l)

BOD5

(mg/l)

COD

(mg/l)

BOD5

(mg/l)

COD

(mg/l)

BOD5

(mg/l)

COD

(mg/l)

BO

(mg/l)

COD

(mg/l)

BOD5

(mg/l)

COD

(mg/l)

BOD5

(mg/l)

M1 10,5 6,3 9,7 5,8 8,1 4,7 11,0 6,1 10,0 5,9 11,5 6,3

M2 23,0 10,4 24,0 11,0 25,0 13,1 23,5 12,3 24,5 12,5 23,5 13,0

M3 20,0 12,0 19,0 10,2 21,0 11,4 18,5 9,5 20,0 11,5 20,5 12,5

M4 19,0 11,0 18,0 9,8 20,0 10,7 24,0 10,2 23,0 10,6 24,4 11,0

M5 32,0 16,8 26,0 17,1 28,0 15,0 31,0 16,3 30,0 17,5 32,0 17,8

M6 20,0 12,0 19,5 11,5 23,0 13,5 21,0 13,7 22,8 14,0 23,2 13,6

M7 33,0 19,0 35,0 17,6 33,6 18,5 37,0 16,0 35,6 16,8 37,1 17.4

Ngun nc sng B ti cc im nghin cu tng i tt, cht lng nc c xu th gim t trung lu v h lu. Vng nc p thy in Hng in (M1) tng i sch (bn va ), c th dng cp nc cho sinh hot, cho cc ngnh cng nghip, nng nghip v gii tr. Vng nc t cu Hin S (M2) n ng ba Snh (M7) b nhim hu c v nhim phn vt qu mc tiu chun cho php dng cho cht lng nc mt (QCVN08: 2008/BTNMT) nhng ch yu vn nm trong gii hn loi B. T cc ch s sinh hc ASPT theo h thng tnh im BMWPViet cho thy cht lng nc sng B nhim hu c mc nh. Hu ht cc ch s ASPT thu c u thuc mc bn va . Ch c ti p thy in Hng in c mc bn va . Gi tr ch s sinh hc dao ng t 3,10 im n 5,30 im. iu ny c th hin kh ph hp khi phn tch cht lng mi trng nc v khi tnh theo h thng im BMWPViet

Theo h thng tnh im BMWPViet, cht lng nc sng B hu ht thuc loi bn va ( - Mesosaprobe) nhng gia cc im c ch s sinh hc ASPT khc nhau, dao ng trong khong 3,1 5,3. Ti vng nc ng ba Snh (M7) l im nm cui ca dng chy, ni hi t vi sng Hng li chu nh hng ca hai ngun nc ngt v mn nn c mc nhim hu c kh cao. Bn cnh , on sng ny c ch dng chy tng i n nh v vn tc dng chy phn b kh u. V vy, khng c s chnh lch ln gia cc t kho st.

4. Kt lun v ngh

4.1. Kt lun

- Nghin cu pht hin c 44 h VKXS c ln: 28 h thuc 2 lp ca ngnh Chn khp (Arthropoda), 15 h thuc 2 lp ca ngnh Thn mm (Mollusca), 1 h thuc

138

lp a (Hirudinea) v mt s i din ca lp Giun t t (Olygochaeta), Giun nhiu t (Polychaeta) ca ngnh Giun t (Annelida).

- S dng VKXS c ln nh gi cht lng nc cho thy cht lng nc mt sng B tng i tt. Mc nhim ch t mc bn va ( - Mesosaprobe) n bn va ( - Mesosaprobe), c th cp nc cho sinh hot khi c x l lc bng b.

- Kt qu nghin cu cht lng nc da vo ch th VKXS c ln cho thy tng ng khi nh gi cht lng nc da vo cc ch tiu ho hc, theo c th s dng ch th sinh hc VKXS c ln nh gi mc nhim ca cc ngun nc mt ti Tha Thin Hu. y l phng php c nhiu u im gp phn a dng ho cc phng php nh gi cht lng ngun nc mt ni a.

4.2. ngh

- Phng php nh gi cht lng nc bng sinh vt ch th, c bit l VKXS c ln l mt phng php c rt nhiu u im, gp phn quan trng cho s pht trin bn vng mi trng sinh thi. V vy, phng php ny cn c nhng nghin cu cc thy vc khc Tha Thin Hu v m rng n cc thy sinh vt khc xy dng mt bng ch s sinh hc nh gi cht lng nc c th p dng trn ton Quc.

TI LIU THAM KHO

1. B Ti nguyn & Mi trng, Quy chun K thut Quc gia v cht lng nc mt

(QCVN08: 2008/BTNMT), 2008.

2. Nguyn Xun Qunh, Clive Pinder, Steve Tilling, nh loi cc nhm ng vt khng

xng sng nc ngt thng gp Vit Nam, Nxb i hc Quc gia H Ni, 2001.

3. Nguyn Xun Qunh, Clive Pinder, Steve Tilling v Mai nh Yn, Gim st sinh hc

mi trng nc ngt bng ng vt khng xng sng c ln, Nxb i hc Quc gia

H Ni, 2002.

4. ng Ngc Thanh, Thi Trn Bi, Phm Vn Min, nh loi ng vt khng xng

sng nc ngt Bc Vit Nam, Nxb Khoa hc & K thut, H Ni, 1980.

5. Andrew D. Eaton, Lenore S. Clesceri, Eugene W. Rice, Arnold E. Greenberg, Standard

methods for the examination of water & wastewater (21 st Edition), 2005.

6. Environment Agency Assessing Water Quality, General Quality Assessment (GQA)

scheme for Biology. Environment Agency, Bristol, UK, 1997.

7. J.A.M. Hellawell, Biological indicators of freshwater pollution and environmental

management. Ellesmere Applied Science Pulishers, London, 1986

139

8. N.De.Pauw and H.A.Hawkes, Biological monitoring of river water quality, River

Water Quality Monitoring and Control, Aston University Press. 1993, 87-111.

USING LAGER SIZE INVERTEBRATES TO ESTIMATE WATER QUALITY IN BO RIVER, THUA THIEN HUE PROVINCE

Vo Van Phu, Hoang Dinh Trung, Le Mai Hoang Thy

College of Science, Hue University

SUMMARY

The main objective of this study was to look for a biotic index to assess the surface

water quality. The BMWP score system for Vietnam and ASPT indices has been applied to

assess the water quality of 7 main sites in Bo river, Thua Thien Hue province. The study was

carried out in January July of 2008. As the results, 44 macroinvetebrate families belonging to

7 classses and 3 phyla (Annellida, Arthropoda and Mollusca) were recorded. Among these

families, 37 families belong to the list of BMWPViet scoring system.

The composition coverved some predominant familes, such as Gastropoda, Bivalvia,

Decapoda, Hemiptera, Coleoptera, Ephemeroptera and Odonata; each of them has more 2

species. Data analysis showed that in Bo river, the BMWPViet scores are relatively hight, the

biotic indices (ASPT) ranging from 3,1 to 5,3. The application of macroinvertebrates as a biotic

index to evaluate the water quality level of quite polluted (-Mesosaprobe) to level of quite

polluted (-Mesosaprobe). This evaluation corresponded the water quality when assessed by

chemical methods. We conclude that macroinvertebrates can be a good biotic index applicable

for water quality assessment.

All the materials are preserved in 4% formalin and deposited in the Departement of

Invironment laboratory, Faculty of Biology, Hue University of Science.