cong cu khoa hoc va ky thuat danh gia tac dong moi truong p1 558

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Ban th k U hi sng M Cng Chng trnh o to mi trng

cng c khoa hc v k thut nh gi tc ng mi trng

Phnom Penh 10/2001

http://elib.ntt.edu.vn

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Cng c khoa hc v k thut nh gi tc ng mI trng

Chng trnh o to mi trng Ban th k U hi 1

Mc lc

BI 1 - NH GI TC NG MI Trng: ng dng cc cng ngh KHOA HC..2 Gii thiu .....................................................................................................................2 Bi cnh kinh t x hi ................................................................................................2 Sinh thi thu sinh .......................................................................................................3 nh hng tim tng ....................................................................................................3 Cc bc tip theo .......................................................................................................5

bi 2 - gim st c bn......................................................................................................... 6 Xc nh mc tiu chng trnh ..................................................................................6 Thit k kho st..........................................................................................................7 Bo m cht lng - kim tra cht lng - QA/QC .................................................12

bi 3 - gim st nh hng mi trng....................................................................... 13 Yu cu thit k s b ...............................................................................................13 Chng trnh ly mu ................................................................................................14

bi 4 - nh gi NGUY C SINH THI ................................................................................. 22 Xc nh vn .........................................................................................................22 nh gi nguy c e do ...........................................................................................25 nh gi nh hng...................................................................................................26 Nu c im nguy c ...............................................................................................26 Qun l nguy c.........................................................................................................28

bi 5 - nh gi nguy c sinh thi: v d nh my ch to bt giy................ 30 Xc nh vn .........................................................................................................30 Xc nh v nu c im ca cc tc nhn c hi ...................................................31 Pht hin v nu c im ch th nhn....................................................................34 M hnh khi nim.....................................................................................................35 nh gi mi e da..................................................................................................35 nh gi nh hng...................................................................................................36 c im ca nguy c ...............................................................................................38 Phn tch tnh khng chc..........................................................................................38 Tm quan trng v sinh thi ......................................................................................39 Qun l nguy c.........................................................................................................39

bi 6 - gii thiu m hnh mi trng........................................................................... 40 M hnh khi nim.....................................................................................................40 M hnh l thuyt ......................................................................................................42 M hnh thc nghim.................................................................................................42

bi 7 - v d m hnh mi trng ng dng ............................................................... 47 Mi trng nh gi ..................................................................................................47 c tnh ho hc........................................................................................................49 Cc m hnh...............................................................................................................51 u im v hn ch ca m hnh mi trng ...........................................................54

sch tham kho .................................................................................................................. 56


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Bi 1 - nh Gi Tc ng Mi Trng: ng dng cc cng ngh KHOA Hc

Gio trnh D trc y bao hm thut ng v cc yu cu v th tc nh gi tc ng mi trng (EIA) lin quan ti d n. Gio trnh ny cp c th ti mt vi cng c khoa hc thng s dng trong thc hin EIA. Mt v d c tnh gi thit v mt nh my bt giy v giy lu vc sng M Cng (MRB) c s dng xuyn sut gio trnh minh ho cc k thut EIA trong thc tin, nh gim st mi trng, nh gi nguy c i vi sinh thi (ERA), v m hnh mi trng.

Gii thiu

Nh my bt giy v giy gi thit ang hin c t Cmpuchia trn b sng M Cng (hnh 1). Nh my bt u hot ng nm 1978, v sn phm l giy trng. Nh my nm trn b sng, khong 10 km thng lu ca hai lng, v xung quanh l rng cn nhit i. Tng din tch khu t nh my chng 7 hc ta. Sn lng ca nh my c chng 470 ti 484 tn giy kh/ngy. Nh my thi t 5.900 n 10.000 m3/ngy nc thi vo sng M Cng. Mt s loi ng vt hoang d bao gm ri c, mt s loi b st v vt tri vng ny. Nh my ny khng phi l c s cng nghip duy nht on sng ny. Cn c mt c s nui trng thu sn khong 2 km thng lu.

Ch nh my giy quyt nh tng sn lng bt giy v giy v ngh c m rng nh my ra nhng vng nng nghip v vng rng ln cn. S m rng nh my s gy ra nhng tc ng mi trng c hi. Nhng tc ng ny cn c nhn r trc khi tin hnh xy dng phng nga v gim nh nhng nh hng c hi v cng ng u vi nhng tn tht v ti nguyn thin nhin khng th trnh khi.

Bi cnh kinh t x hi

Lng gn nh my nht trn b pha ng ca sng khong 10 km v h lu. Lng th hai cn xa hn chng 2 km v h lu, trn b pha Ty. Dn c c hai lng khong 4.000 ngi. Nhn dn y nh c sng quanh nm v trng la mt v ma kh cnh ng ngp lt ca dng sng. H cng dng nc sng ly nc ung v ti rung. Quy m trung bnh ca mt h gia nh l 6 ngi. Ngh nh c c truyn l ngun cung cp m quan trng nht, vi loi c c em bn ch pha h lu, nhng phn rt ln c bt c u dnh n trong gia nh.

Dn lng khai thc rng ln cn ly ci t v cho cc mc ch khc. Rng v ng vt hoang d c tm quan trng to ln v vn ho i vi ngi dn.


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Hnh 1: Bi cnh nh my bt giy v giy gi nh trn b sng Mkng

Sinh thi thu sinh

Nc chy qua nh my c hm lng cht dinh dng v amniac cao do c s nui trng thu sn thi ra, d c mt lng nc sch b sung t cc sng nhnh chy vo sng. Nc thi ca nh my v nc sng khng c gim st thng xuyn. Chc chn l nc thi cha ng nhng ht si c pH cao v hm lng ioxin tng i cao. Trc y sng vn rt giu c v cc loi c, trong quan trng nht l c da trn v c chp rt quan trng i vi nhn dn. nh hng ca nc thi i vi qun th cc loi c chc l c nhng khng c nghin cu no c tin hnh. Tnh sinh hc v di c ca cc loi c khng c nghin cu chu o, tuy nhin dn bn a u nht tr rng lng c nh bt c gim dn t khi nh my bt u hot ng.

nh hng tim tng

V d v nh my gi nh ny s lm ni bt mt s kha cnh tc ng mi trng thng qua vic m rng nh my: rng, cht lng khng kh v mi trng nc sch. Cn c nhng kho st kim tra c bn pht hin thc trng v gip xc nh tm quan trng ca nhng tc ng . Tc ng mi trng c th ny sinh theo s m rng nh my c tm tt nh sau:

Rng

- Ph hoi rng

- Tn tht v a dng sinh hc v mi trng sng


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- Pht trin c canh nu mt phn khu vc ny c trng rng li

- Tn tht ca cc loi cng c cacbon

- Xi mn t

- nh hng n cht dinh dng trong t v cn bng cht hu c

- nh hng n cn bng nc

- G tr nn khan him v ny sinh tranh chp v g t

- Nhng a im c tim nng v kho c b ph hoi

Khng kh

- Tng cng bc x khng kh gy hiu ng nh knh khin cho kh hu b thay i nghim trng

- Cn kit zn

- Thi cht c (ma axit)

- Cc ht l lng v bi

- Ting n

- Mi hi

Nc sch:

- Cht thi cha hm lng cao nhu cu oxy sinh ho, cc cht rn l lng v clo hu c ra sng.

- Mi trng sinh sng ca c b thay i qua vic c thm nhiu vn g v bin i dng chy, v do hin tng lng ng nghim trng trong qu trnh khai hoang t ai v m rng khu vc nh my.

- Cht thi gy ra s nhim c mn tnh hay cp tnh i vi ton b sinh vt thu sinh do cc ho cht gy ra nh sulfate, dioxin, nhng hp cht hu c x l bng clo.

- Kh nng nhim bn nc ngm, nc ung v nc ti.

- Cht thi v nhim bn ho cht, cht c thot t cc bi cht thi

- Cht thi rn v nguy him (v d dioxin, v cy, ph thi, bn cn)

Nh my giy v bt giy thi ra sng hn 25.000 lt nc thi cho mi tn bt giy sy kh. Lng nc thi d tnh s tng ln cng vi vic m rng nh my. Hin nay cht thi lng thng bao gm c cht hu c v v c, cng nh cht ho tan v khng ho tan. Trong khi vi cht ho tan c loi b nh bn cn chng hn, th


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phn ln li nhp vo mi trng nc nhn vo di dng cc ht v cht rn l lng. Cht ny to ra nhng tm thm bng si, lm gim kh nng xuyn qua ca nh sng mt tri, do nh hng n c cng ng sinh vt y sng v mi trng sinh sng ca c.

Cht thi lng ca nh my cng cha ng nhng cht hu c x l clo. Cc qu trnh dit khun v oxy ho cc cht ho hc dn ti s cn kit oxy ho tan cn thit cho i sng thu sinh, ng thi cng lm tng nhu cu xi sinh ho (BOD). Cc cht hu c x l clo gm nhng halogen hu c d hp thu (AOX) bi than hot tnh, v d nh dioxin v furan, v cc hp cht hu c lng cn c th c tc dng nh nhng cht dinh dng. Dioxin c khuynh hng tch t sinh hc t nc vo m ng vt thu sinh ri pht trin theo con ng sinh hc trn dy chuyn chui thc phm. Tt c cc thng s ny cng tc ng ca chng ln mi trng nhn vo s tng ln cng vi lng thi cao hn i theo vic m rng nh my.

Kinh t - x hi

- Quyn hng dng t hay quyn quy c, nhu cu c dn theo rng, cc hnh thc s hu t quy c v nn np canh tc khng c p ng

- Dn lng phi chuyn i ni khc do nh bt c mt ma

- C th c nhng vic lm mi

- C th kch thch pht trin kt cu h tng v kinh t a phng

Vi vic m rng xy dng nh my gi nh ny, ting n, cc ht bi phng ra xung quanh khin cho dn lng vng ln cn lo lng trong thi gian trc mt. Rng b khai thc, ng x c xy dng v s vn chuyn, i li s nhn nhp hn. Nu nh my c nng cp v c thp lc kh th s loi b c nhiu loi kh thi trong qu trnh sn xut.

Trong khi mt s t dn bn a phn khi vi kh nng c vic lm mi v u t ci thin kt cu h tng v trng s a phng, th dn lng li lo u v kh nng phi chuyn ch do mt nhng mnh t sinh sng v g un, cng nh do tnh trng lng c nh bt c gim st.

Cc bc tip theo

Kch bn v vic m rng nh my giy v bt giy gi nh ca chng ta s c trin khai nhng bi hc sau khi chng ta tm hiu cn k s p dng cng c khoa hc EIA c chn.


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bi 2 - gim st c bn

Gim st c bn nhm xc minh thc trng mi trng v cung cp d liu c bn cho nhng so snh trong tng lai. Gim st c bn rt quan trng i vi c vic nh gi tc ng mi trng (EIA) ln nh gi nguy c i vi sinh thi (ERA). Gim st c bn ch yu kho st nhng bin i vt l, ho hc v sinh hc trong mt h sinh thi. Cc chng trnh gim st c th c tin hnh trong mt thi gian tng i ngn (tc l khng y 1 nm) hoc c th l chng trnh nhiu nm xc nh xu hng ma v s bin i ca thin nhin trong mt h sinh thi.

V d ni trn v nh my giy v bt giy gi nh s c s dng xuyn sut bi ny trong vic chi tit ho cc kha cnh ca gim st c bn.

Xc nh mc tiu chng trnh

Bc u tin ca bt c mt chng trnh gim st c bn no l xc nh r mc tiu chng trnh. Bc ny rt quan trng v s gip ch nhiu cho vic thit k kho st. Vic xc nh mc tiu chng trnh thng i hi phi lin h vi cc c quan hu trch ca chnh quyn v nhng ngi cng chung quyn li trong vic vch ra v t th t u tin cc mi quan tm v qun l. Thng tin ny c th dng tinh lc chng trnh gim st v gip d tnh loi thng tin cn thit cng nh nhng ch tiu cch dng thng tin trong ra quyt nh.

V d v nh my ny to iu kin thun li cho thy s hnh thnh cc mc tiu chng trnh. Trong v d ny, gim st c bn m rng nh my s c ln k hoch cho mi trng thu sinh. Mc tiu ca chng trnh gim st c bn ny s c xc nh trn c s tham vn c quan nh nc c thm quyn, tt nht l thng tin cho cng lun v chc s l:

Nhm nu bt c im mi trng thu sinh thng lu v h lu nh my trc khi xy dng v m rng.

Vic thc hin mc tiu c th ny s cung cp d liu c bn c th em ra so vi d liu thu thp c trong khi v sau khi m rng nh my xc nh bn cht v mc ca cc tc ng i vi mi trng thu sinh tip nhn, sng M Cng.


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Thit k kho st

Vi cc mc tiu chng trnh gim st c xc nh r, ta c th thit k mt t kho st gim st c bn. Thit k kho st gm c hai nhim v ch cht: xc nh nhng a im cn gim st v chn nhng tham bin gim st. thc hin nhng nhim v , nn xem li cc t kho st trc cng ti vng . i khi, d liu hin c tnh trng mi trng c bn, m khng cn ly thm mu ngoi hin trng na. Tuy nhin, d liu c bn thng rt hn ch cc quc gia ven sng thuc h lu vc M Cng, v c th phi thu thp trc khi ph duyt bt c mt d n quy m ln no, nh vic m rng nh my ny chng hn.

Khi thit k t kho st gim st c bn, vic lp k hoch ng n c th lm cho chng trnh hu hiu hn v tit kim hn v lu di. Nu khng c lp k hoch ng n, th c th xy ra tnh hnh sau y:

- Cc tham bin quan trng v mi trng b b qua

- D liu khng lin quan n cc mc tiu hoc tr li cc cu hi kho st

- D liu km cht lng v do khng ng tin cy

Chn a im

Cn xem xt mt s yu t khi chn nhng a im ly mu. a im phi d xc nh ly mu nhiu ln cng nh d tip cn. Cng cn chn nhng a im bao hm cc c im mi trng sng nh nhau (v d c im y, su, lu lng, mn che ph b mt dng chy) gim thiu tnh khng n nh t nhin gia cc im.

nhng vng sp trin khai mt d n, cc a im gim st c bn phi nm trong c vng i chng (tc l khng b nh hng) v vng c th b nh hng. V d, gim st c bn i vi nh my gi nh ni trn cn c tin hnh ti cc trm pha thng lu v h lu ni nh my cht thi ra sng. Khi chn nhng a im thng v h lu ny, cn xc nh cc vng cc dng nc thi trn ln vo nhau (tc l bin ng v bin ngang ca dng chy). V hai l:

1. m bo rng cc im c th b nh hng s nm trong vng ho trn nc thi.

2. m bo cc trm i chng nm ngoi bt c vng c th b nh hng no.

Vng ho trn nc thi thng c xc nh bng cch dng mt nghin cu phc nhnh o vng ho trn nc thi v cho bit c im ca cc nhnh tc ng. Cc nghin cu phc nhnh c tin hnh bng cch o nng ca cc cht nh du (v d nhng ho cht hoc cho thm thuc mu) trong dng nc thi hoc qua nhng m hnh d bo. Cht nh du l nhng cht d o, hoc l mt phn nc thi hoc c cho thm vo v c th gim st o mc thi. V nghin cu ny khng th thc hin chng no cha hon thnh vic m rng nh my, c th dng m hnh d bo m phng dng nc thi. Cc m hnh c th da trn nhnh hin


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c c iu tra v cng b cng vi vic tng lng nc thi tng ng. Khi bit cc c tnh ca vng ho trn nc thi, vng kho st c th c phn chia thnh cc vng i chng v cc vng nh hng.

Cc im i chng cn nm nhng vng khng chu nh hng ca dng thi ca nh my v ch t cng bao gm mt trm ngay pha thng lu im x ca nh my. Khong cch gia im i chng v im u tin b nh hng h lu phi ngn nht gim kh nng nhm ln vi nhng cht nhim ca ngun khc khng dnh dng g ti nh my. im i chng khng nht thit phi i din cho tnh trng ban s m nn l nhng vng chu nh hng t hoc b xo trn t nht.

Thng cn c nhiu hn mt im i chng nh gi nhng nh hng c th xy ra. C th c mt im th hai trn cng on sng ny c thm thng tin v tnh bt n nh ca thin nhin. Nhng im i chng khc cng c th c chn u ngun sng c hiu bit chnh xc liu c nhng ngun gy nhim khc thng lu hay khng.

Cc im b nh hng cng cn c chn nhng ni gn v xa v tr d n v pha h lu. D liu ca cc im ny dng m t c im tnh trng mi trng hin thi v nh gi mc tc ng theo s m rng nh my. Cc im gn hin trng cn nm ra vng pha long ban u bn trong nhnh thi. Vng pha long ban u l vng k cn ngay ni nc thi ca nh my bt u chy vo sng. Vng ny thng c c im l dng chy ri v thng khng c xa ni thi qu 5 n 50m.

Cc a im xa hin trng cn nm xa im x pha h lu cho nc thi v nc sng ho trn vo nhau.

Hnh 1 cho thy cc trm gim st c bn c chn cho vic m rng nh my. Trong v d ny, cc m hnh d bo c dng d on lng nc thi. C s chn cc im ly mu nh sau:

- Trm R1 l mt trm i chng nm thng lu nh my ti mt sng nhnh ca sng M Cng. Do khng c ngun gy nhim, nn a im ny phn nh tnh trng t nhin

- Trm R2 l mt trm i chng th hai nm v pha thng lu khng xa nh my v phn nh tnh trng t nhin ca dng sng. Khng ging nh im R1, im ny c th chu nh hng ca nhng cht thi khc thng lu (v d cc hot ng nui trng thu sn, tiu nc cho nng nghip).

- Trm FF l mt trm xa hin trng cch im x chng 250 m v pha h lu v phn nh tc ng ca nc thi nh my sau khi pha long v trn ln nc thi trong nc sng.


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Gim st cc tham bin

Do khng th kim tra tt c cc thng s ho hc, vt l v sinh hc trong mt h sinh thi th cn tp trung vo mt s t cc thng s ch cht phn nh tnh trng c bn chung. Tiu chun chn la cc tham bin bao gm:

- Tng ng vi cc mc tiu gim st

- nhy v thi gian p ng

- bin thin

- Nhng vn thc tin (v d d o, chi ph)

Hnh 1 V tr cc trm ly mu cho nh my bt giy

Cc thng s thng c gim st trong cc chng trnh gim st c bn gm:

- t

- Thc vt

- Sinh vt sng y nc v cn trng trn mt t

- Cht lng nc v cht lng ng

- Ti nguyn thu sn


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Trong khi cc chng trnh gim st c bn thng tp trung vo cc thng s ho hc v vt l, cc tham bin sinh hc thng c ch nhiu hn trong vic m t c im tnh trng mi trng. Sinh vt sng th hin thng nht nhng xo trn xy ra trn nhng vng rng ln hn. V d, sinh vt sng sng c th cho php nh gi nh hng ca cc hot ng trn khp mt lu vc sng. Sinh vt sng mt vng cng gii p hng lot nh hng mi trng gy ra cho con ngi v thin nhin, nh nc thi c hi, hin tng lm giu cht dinh dng v s xung cp mi trng sng. Thm vo , sinh vt sng mt vng thng ch ra s thay i mi trng nhy cm hn nhng phn tch v ho nc hay bn ct. V d, m sinh hc c th tch t cht gy nhim mc d pht hin hn trong nc hay bn ct.

Mt chng trnh gim st c bn i vi vic m rng nh my phi ly mu nhng tham bin tm thy h sinh thi thu sinh v y l mi trng tip nhn cc e do. Trong khi dng nhng tiu ch ni trn, c th chn nhng tham bin sau y m t c im tnh trng t nhin ca sng M Cng: ho nc, ho bn ct, cng ng sinh vt khng xng sng di y v cc ti nguyn thu sn. C s hp l chn tham bin v chn phng php ly mu s c ni r phn sau.

Ho nc

Ho nc l mt tham bin thng gp trong cc chng trnh kho st thu sinh v dng o mt s thng s nh pH, tnh dn in, tng lng cht rn l lng (TSS), cht dinh dng, cng v cc kim loi. Vic phn tch ho nc trong nh my giy v bt giy v d cng c th bao gm c nhng hp cht hu c, nh cc axit nha v phenol sn sinh ra trong qu trnh x l bt giy, cng nh nhng thng s quan trng khc khi kim tra nc thi nh my bt giy.

C mt s l do v sao ho nc thng c xem nh l mt phn ca cc chng trnh gim st c bn. Cc mu nc rt d thu thp v phn tch v gip o chnh xc cc cht gy nhim ho tan trong mt h sinh thi thu sinh. Tuy nhin, ho nc cng c nhng thiu st. Mt trong nhng nhc im ln nht l mi mu nc ch ni ln tnh trng cht lng nc ti thi im ly mu v c th khng i din cho cht lng nc trong mt giai on di ca mi trng tip nhn.

Ho bn ct

Ho bn ct cng thng c nh gi trong cc chng trnh gim st thu sinh v ch yu c tin hnh khi cc hot ng c th gy xi mn t hoc lm cho cc cht nhim ho tan tch t li thnh lp bi lng qua thi gian. Tiu biu l phn tch ho bn ct bao gm m, c ht, tng cacbon hu c (TOC), cht dinh dng v cc kim loi.

Phn tch TOC trong lp bn ct rt quan trng trong vic xc nh d dng t l mt cht nhim no nhim vo sinh vt thu sinh, nht l trong trng hp cht thi xut hin trong mt thi gian ngn. Vi cht nhim, nh dioxin, d gn kt vo cht hu c. Lng sng vi tng cacbon hu c cao l nhng ch trng thun li cho nhng cht nh vy. Nhng cht k nc (ght nc) s gn kt vo lp bn ct v,


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qua thi gian c th b vi trong nhng lp sau, s lm gim lng cht nhim sinh hc.

Ho bn ct l mt thnh phn quan trng ca chng trnh gim st c bn do mt lot l do. Lp bn ct tch lu nhim qua thi gian v cho thy, v lu di, s bin i mt on sng. Khng ging vi ho nc, ho bn ct t bin i hn v gip o c nhng cht nhim t ho tan nh kim loi v cht hu c.

Cng ng ng vt khng xng sng di y

C mt lch s lu di v dng cc ng vt khng xng sng di y trong cc chng trnh gim st c bn. ng vt khng xng sng di y l mt tham bin kim tra thng gp v nhiu l. Chng phn b rng ri, kh phong ph, d thu thp v d pht hin. Cc ng vt khng xng sng di y a dng v phong ph rt cn thit duy tr mt qun th thu sinh phong ph mnh hn dy chuyn thc phm. ng vt khng xng sng di y nhy cm vi nhng bin i, gip o c chnh xc nhng tc ng cp cng ng v phn nh tc ng tch lu ca cc tnh trng qua v hin ti. ng vt khng xng sng di y ni chung t di chuyn, do tiu biu cho mt quy m thch hp vic gim st x cht thi tp trung. Cc mu ng vt khng xng sng di y c th c nh gi v ch s a dng, mc phong ph trong chng loi, di do s lng, tri v s c mt/vng mt ca chng loi cha nhim.

Ti nguyn thu sn

C cng lm mt tham bin thng c gim st cc chng trnh gim st c bn. C thng ni chung nhy cm vi cht nhim v phn nh nh hng ti mi trng nhiu cp (v d c th, cng ng, qun th). C thng c kho st b sung cho kho st ng vt khng xng sng di y v chng c vng i di hn v phn nh nh hng lu di i vi sinh vt thu sinh. C cng c ng hn ng vt khng xng sng v do cho thm thng tin v tnh trng h sinh thi. Kho st ngh c on sng M Cng chu nh hng ca nh my trn cn bao gm cc mu xc nh nhng loi c hay sng ti on sng ny, cng nh ch di c ca chng - thng tin ny rt cn thit trong vic quy hoch cc bin php gim nh i vi vic m rng nh my . Hn na, do nh my nc thi t nm 1978 nn cn kim tra m c xem c dioxin hay khng.

Bn cnh nhiu l l tch cc a c vo mt chng trnh gim st c bn, cng c vi kha cnh tiu cc. Vic thu thp mu c th kh tn km v mt thi gi. Thm vo , quy m c th qu rng khng th gim st ni vic x nc thi tp trung, nht l khi phi gim st cc loi c rt c ng (v d kh xc nh mi e do tim tng ca lng nc thi nh my i vi cc loi c c ng).

Cc phng php gim st c nhng sng ln thng tp trung vo nhng loi c gim st (v d loi c gim st trong vng kho st) c c trm b nh hng v trm i chng. Phi dng t ra l hai loi gim st v t ra phi c mt loi c y nh Pangasianodan gigas (c da trn ln) chng hn. Cn tham vn mt nh sinh hc giu kinh nghim v cc trc khi chn loi. Nn tp hp t nht 20 con c v 20 con ci


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mi trm v phn tch nhng thng s nh di, trng lng, tui, iu kin bn ngoi v kh nng sinh sn.

Cc phng php chn mu phi ring cho tng a im v da vo cc nguyn tc vt l v sinh hc chi phi s phn b c trong sng. Vi phng php ly mu bao gm li ging, li vt, li ko v cu.

Li ging thng dng kim k c bit sng, h. Li c treo dc trong nc v c dnh vo mt li. C mt li chn ng vi nhng loi c v c c thch hp v hn ch vic bt thm nhng loi v c c khc ngoi quy nh.

Li vt (li ko) c th dng ly mu ch nc cn hay mi trng sng gia hai mc nc dnh v nc rt ti ch nc thi vo sng.

Cu c th dng cn cu, ng cun, li cu, dy cu, phao, mi, cch nh v cn s kin tr. Phng php ny dng ly mu nhng loi c tng i t di chuyn, v c tnh la chn rt cao ch nhm vo loi c ly mu m thi. Tuy nhin, cu c rt tn sc v tn th gi m d liu thu c th hn ch trong s dng v k thut thin nhiu v c c v loi c.

Bo m cht lng - kim tra cht lng - QA/QC

Bo m cht lng/kim tra cht lng l mt thnh phn ch yu ca mi chng trnh gim st c bn. Bo m cht lng (QA) c lin quan ti nhng th tc qun l do bn ngoi i hi, chng bo m d liu c c s khoa hc. Kim tra cht lng (QC) l mt kha cnh ring ca bo m cht lng v c lin quan n nhng k thut o lng v nh gi cht lng d liu. Bo m cht lng/kim tra cht lng ch yu l mt phng tin bo m d liu c cht lng chp nhn c, t c th rt ra kt lun c cn c khoa hc. iu ny c thc hin qua cc th tc m bo cht lng ton b, nh hun luyn nhn vin, s dng cc phng php tiu chun ho, cng nh cc bin php kim tra cht lng.


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bi 3 - gim st nh hng mi trng

Mt chng trnh gim st nh hng mi trng (EEM) nhm nh gi tc ng mi trng nh my gi nh thi nc thi vo sng qua thi gian. t nht, chng trnh EEM ca nh my phi nhm bo v c, mi trng sng ca c v vic s dng ti nguyn thu sn. Chng trnh EEM ca nh my phi c tnh thch ng, ni cch khc, n phi linh hot p ng nhng bin i theo thi gian ca nhng tc ng mi trng tip nhn. Nu cn xem xt mt thng s mi hiu r hn mt tc ng mi ti vng kho st EEM, th chng trnh phi a thng s mi vo lch trnh gim st.

Mt chng trnh EEM in hnh bao gm 2 phn:

1. Yu cu thit k s b

2. Chng trnh ly mu - nhng kho st EEM vi mt thnh phn gim st hin trng v kim nghim phng th nghim.

Yu cu thit k s b

Nh my c th ch phi p ng yu cu ny mt ln, tr khi trong tng lai c thm k hoch m rng nh my na. Nu lng nc nc thi t qu trnh x l bt giy, v tr x hoc tnh trng mi trng tip nhn khng thay i ng k qua thi gian, th thng tin sau y cn c nh l mt phn ca nh gi tc ng mi trng (EIA) cho d n m rng hin hnh. Thng tin quy nh giai on thit k s b bao gm:

- Quy m khu vc kho st, k c vng ho trn nc thi v nhng a im i chng tiu biu

- M t c th mi trng sng thu sinh tip nhn nh hng chn nhng trm ly mu loi c v ng vt khng xng sng y thch hp.

- Cht lng v vic s dng ti nguyn thu sn ti mi trng tip nhn (v d tnh hnh nh bt a phng)

- Thng tin v s di do tng i ca c ti khu vc kho st v la chn hai loi c gim st.

- Thng tin v bt c nhng nhn t gy nhiu hoc c th gy nh hng cn phi c xem xt trong qu trnh thit k kho st v gii on kt qu

- Cht lng nc thi v m t c im nc thi.

M t vng ho trn rt quan trng m bo cc trm ly mu nm trong vng , cn cc trm i chng th ngoi xa bt c vng nh hng tim tng no. phn ln cc on sng tip nhn, vng pha long bin i tu theo nhng thay i dng chy ca sng, mc v khi lng x cht thi. Ni chung, vng ho trn nc thi cn


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c m t ng vi tnh trng pha long t nht (mc ti a ca nhnh cht thi v tnh trng trung bnh nhiu nm). Nhng im nm trong vng pha long t nht b lng nc thi nh hng nhiu nht. Nhng im nm ngoi bin gii mc ti a u khng chu nh hng ca dng chy v c th c coi l nhng trm i chng. Tnh trng trung bnh nhiu nm xc nh bt c tc ng di hn no ca vic x cht thi.

Mt khi xc nh vng ho trn, tip n s xc nh nhng vng lng ng. Khi vn tc nc gim, cc ht lng xung, nhng ht mn lng vng vn tc chm nht. Vic phn tch cu trc cng ng sinh vt y ti cc vng lng ng rt c ch cho vic xc nh nhng tc ng do nc thi gy ra ti mi trng thu sinh ny.

Bng 1 cho bit nhng nt c trng cn xc nh v bn mt kim k v phn loi mi trng sng. Thng tin ny gip tm ra nhng nhn t c th gy nhiu, nh lu lng ca nhng d n khc, hoc nhng hot ng c th nh hng ti khu vc kho st - rt quan trng trong vic thit k chng trnh gim st cng nh gii on cc kt qu. Thng tin t kim k v phn loi mi trng sng c dng xc nh v tr cc trm ly mu trong nhng mi trng sng tng t ti nhng vng b e do cc nhng vng i chng.

Vic im li lch s v nhng hot ng ca nh my cn bao gm thng tin v cc qu trnh trong nh my, vic x l nc thi v mi s c c th v lan trn cht thi. Vic im li cc hot ng hin ti v qua c th c ch cho vic xc nh nhng lo ngi do cc hot ng vn hnh gy ra cho mi trng. Thm vo , cng cn ch ti thng tin c sn v c im nc thi ca nh my nh:

- pH, lu lng v dn in

- Nhu cu oxi sinh ho

- Tng cht rn l lng

- Nng dioxin

Chng trnh ly mu

Khu vc kho st cho chng trnh gim st tc ng mi trng bao gm 8 v tr ly mu ring bit gi l trm nh thy hnh 1. Cc trm c th c chp nhn, ly mu li v c xc nh v tr theo phng php nh lng (tc l, dng cc to kinh tuyn/v tuyn). Khu vc kho st c chia thnh nhng vng i chng v vng b e do. Mc ch chung ca chng trnh ly mu l thu thp thng tin t c khu vc b e do v khng b e do xc nh liu c tc ng ng k t vic x cht thi ca nh my hay khng.

Trong hu ht cc trng hp, bin gii e do l vng ho trn cht thi, v trong khu vc b e do cn c c trm gn v xa hin trng. t nht, mt trong nhng trm gn hin trng cn c t gn im x cht thi, ngay pha ngoi vng vng ho trn ban u. Cc trm xa hin trng cn c t gn bin gii h lu ca vng ho trn


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cht thi. Nhn chung, cn xc nh cc trm ly mu trong tng khu vc chn xc nh bin i theo khng gian ca tc ng.

(tc l ho trm tch v ho nc) v phm vi nh hng (tc l ng vt khng xng sng sng y) tm ra c im nh hng ca nc thi nh my bt giy. i vi chng trnh KTAHMT ca nh my v d ny chng ti chn tng cng 8 trm ly mu: 2 trm i chng (R1 v R2), 2 trm gn hin trng (NF1 v NF2), 2 trm xa hin trng (FF1 v FF2), 1 trm phn trung tm ca lng chim (CP) v 1 trm h lu vng ho trn nc thi (DZ) (xem hnh 1). Nhim v ch yu ca mt chng trnh ly mu KTAHMT s ni c th nhng phn sau.

Khi so snh vi s liu t cc trm b e do, s liu t cc trm i chng c th ch ra tc ng ln mi trng sng thu sinh, xc nh c khu vc nguy him v minh ho c chiu hng theo khng gian v thi gian.

Hnh 1 V tr cc trm ly mu gim st nh hng mi trng cho nh my bt giy

Cc trm i chng khng phi chu mt tc ng no do vic x cht thi v c cc c im v mi trng sng tng t nh trong vng b nh hng. i khi kh c th chn c khu vc t b nh hng lm trm i chng, v cc hot ng khc (nh n g v tri nui c) gn khu vc kho st c th lm suy gim mi trng thu sinh. Trong trng hp , c th chn cc trm i chng trong nhng khu vc khng b nh hng vi cc c tnh mi trng sng v cc ging loi thu sinh tng t v cng nm trong cng mt lu vc.


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Bng 1 Ti nguyn v mi trng sng trong yu cu kim k cho chng trnh gim st nh hng mi trng

Thng s Cc thng tin cn c trnh by

Sng nhnh chnh v ca sng V tr trn bn

Khu vc c v nui c con V tr tt c cc khu vc bit trn bn

Cc hot ng nh c v nui trng V tr tt c cc khu vc bit trn bn

im ly nc, x nc thi, tiu nc, trn nc thi v im tch t rc thi ti nh my

V tr tt c cc khu vc bit trn bn

Dp v cc chng ngi i vi c V tr tt c cc khu vc bit v khu vc hn ch c di chuyn trn bn

Thc vt ven sng Loi thc vt ven sng v thu sing trn bn

Khu vc pht trin cy trng Xc nh v lp bn khu vc trong vng nhnh nc thi gn hin trng c hin tng sinh trng cy trng thu sinh gim st hoc tng ln so vi khu vc i chng

dc lng sng Mt ct dc t bn a hnh hoc kho st.

Dng chy Tng hp thng k dng chy (m3/s).

Ho nc Bng cc s liu cht lng nc hin c

Mc ch chung ca chng trnh ly mu l thu thp s liu khi qut (c o c ti cng mt ni v cng mt lc) cho c khu vc b e do e do trc tip (tc l ho bn ct v ho nc) v khu vc chu nh hng gin tip (tc l ng vt khng xng sng di y) tm ra c im ca tc ng ca nc thi nh my bt giy. i vi chng trnh EEM ca nh my chng ti chn tng cng 8 trm ly mu: 2 trm i chng (R1 v R2), 2 trm gn hin trng (NF1 v NF2), 2 trm xa hin trng (FF1 v FF2), 1 trm phn trung tm ca nhnh (CP) v 1 trm h lu vng ho trn nc thi (DZ) (xem Hnh 1). Nhim v ch yu ca mt chng trnh ly mu EEM s ni c th nhng phn sau.

Ho nc

Mc ch ca kho st cht lng nc l xc nh c im tnh trng mi trng sng c thng lu v h lu ni nc thi nh my. iu ny cho php nh gi tng qut mi i thay ng k v cht lng nc do nh my gy ra.


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Ni dung phn tch gm:

- Oxi ho tan

- pH

- Nhit

- dn in

- Tng cht rn l lng

Cht lng nc thi

xc nh xem nc thi nh my c gy c (cp tnh) cho sinh vt thu sinh mi trng tip nhn hay khng, cn phn tch nhng thng s sau:

- pH, dn in, nhit

- Tng cht rn l lng v nhu cu oxy sinh ho

- Tng Clo v clo d

- Amoniac

- Nit

- Axit nha v axit bo

- AOX (halaogen hu c d hp ph)

Ho bn ct

Mc ch nh gi cht lng bn ct l lm r c im tnh trng mi trng sinh vt di y thng lu v h lu ch nc thi nh my. V dioxin d phn chia thnh cc cht hu c trong bn ct, thng tin v thnh phn cht hu c ca nn sng Mkng s gip c c tng v lng dioxin c ton b sinh vt y hp thu. Ni dung phn tch ho bn ct gm nhng thng s sau:

- Cc cht dinh dng

- Cc kim loi

- Axit nha v axit bo

- Dioxin

- C ht bn ct v tng cacbon hu c

Gim nh c

Mc ch ca gim nh c trong chng trnh ly mu EEM ca nh my l nh gi nh hng ca nc thi i vi s sng cn, tng trng v ti sinh sn ca c. Vic


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gim nh c tp trung gim st ton b cc thng s sinh vt v hai loi c gim st; c thng l nhng ch bo ng tin cy v s lnh mnh tng th ca c h sinh thi. Vic la chn nhng loi c gim st ph hp phn ln da vo mc b nc thi e do. Nhng loi thng tr h lu sng Mkng trong phn ln hay sut vng i ca chng v t ra t c ng so vi quy m khu vc kho st thng c a chn do chng phn nh tnh trng mi trng ti ch. Nhng loi di c hoc ch dnh mt phn nh vng i k cn khu vc kho st u khng phi l loi ph hp v s e do ca nc thi i vi chng rt t hoc thong qua thi.

Ni chung, kh nng mt loi c b nc thi e do cng ln th gi tr lm loi gim st ca n cng ln. Cn trnh chn nhng loi ln v lng di do nhng con trng thnh loi nh phn ng nhanh hn vi nhng nhn t nguy hi tc ng ti s sng cn v ti sinh sn ca chng. Nhng loi nh hn, vn l thc n quan trng ca nhng loi cc khc c th dng lm loi gim st l tng. Nhng loi b nh bt nhiu cng khng thch hp v thu hoch ln c th che ph nhng nh hng c lin quan ti s e do ca mi trng i vi qun th c c kho st.

L tng nht, nn chn 40 con c mi loi gim st (tc 20 con c v 20 con ci) ti mi v tr ly mu v ghi li s lng, kch c, trng lng, tui, trng lng c quan sinh dc v tnh trng chung v thn hnh ca chng.

Trong khi phn tch v gii on kt qu nn so snh d liu nhng im b nh hng vi im i chng. Nhng khc bit ln v s lng v tnh trng ca c so vi cc trm i chng c th cho bit nhng nh hng c lin quan n nc thi nu c.

Phn tch m i vi ixin c clo ho

V nh my giy v bt giy dng clo ty trng bt giy, nn cn phn tch mc m cha dioxin phn thn c c th n c. Ni chung, loi c no c chn phn tch v phn thn no ca c l phn n c phi c quyt nh trn c s tng im kho st c th. Trong trng hp nh my ny, c th dng loi c da trn ru ngn (Pangasius micronenues) phn tch m. Cng tin hnh th m xc nh gi tr sinh hc ca dioxin i vi nhng sinh vt giu cht dinh dng nh c n tht v chim n tht.

Gim nh ng vt khng xng sng di y.

Gim nh cng ng ng vt khng xng sng nhm m t c th c im ca ton b sinh vt y ti vng kho st nh gi nh hng tim tng ca nc thi nh my i vi iu kin sinh hc mi trng tip nhn. Chng ta tm cch xc nh xem cu trc cng ng sinh vt y c khc nhau gia cc im trong khu vc kho st, so vi cc a im i chng, hay khng. Nu c khc nhau th chng ta mun bit nhng khc bit c lin quan g vi khong cch ti ca x nc thi hay khng (tc l, xc lp bin thin mc nh hng). Cc mu ng vt khng xng sng y cn c phn tch v:

- S phong ph ca loi

- Tng s lng


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- Cc loi gim st bo l cc cng ng ng vt khng xng sng vn lnh mnh

- S vng mt ca nhng loi l ch bo cho tnh trng b xo trn, nh nhng loi c bit l loi n tht hoc chu c nhim

- C ht bn ct v tng carbon hu c

- Phn tch m xc nh nguy c t dioxin

Nhng i thay cu trc cng ng sinh vt sng y l mt ch bo r rng v s xung cp mi trng sng, hoc do mt cht nhim sinh hc hay ho hc (v d dioxin) hoc do mt nhiu lon. S rt phong ph (tc l nhiu loi khc nhau) ca ng vt khng xng sng l bn cht ca mt mi trng sng lnh mnh. iu ny bo m ngun thc n cho cc loi c c tr v v vy thc phm cho dn a phng.

C th dng nhiu ch s khc nhau o s lnh mnh ca mi trng thu sinh qua phn tch cng ng sinh vt sng y. V d ch s EPT dng s phong ph ca Ephemofitera (ph du), Plecoptera (stoneflies) v Tricoptera (caddiesflies) ch ra cht lng tt ca nc v bn ct. Nhng loi ny c coi l loi gim st, nhy cm vi nhim biu th tnh lnh mnh tng th ca mi trng thu sinh. S EPT t i biu th cht lng mi trng thu sinh b xung cp. Cc loi chu c nhim cng d nhn bit trong c rui nhu, rui en (chironomidae, simuliday), con a (Hirudinea) v su nc (Oligochaeta). Da vo nhng m t ni trn v nhng loi sng y, ngi ta lp ra nhng ch s sinh hc xc nh s trung bnh ca cc tr s chu ng nhim cho nhng loi khc nhau trong mt mu. Tr s chu dng c lng ho trn thang t 0 n 10, trong 10 ch sc chu ng ln nht. Nhng ch s tng t vi EPT hay nhy cm nhim ca nhng loi sng y, c dng Bc M v Chu u, rt nn c trin khai p dng cho mi trng thu sinh c th ca sng Mkng.

Th nghim c t trong phng th nghim

Cc th nghim c tnh c dng t nhng sinh vt c th vo mt mi trng (v d nc, bn lng hay t) v nh gi nh hng i vi s sng cn, tng trng, ti sinh sn v/hay hnh vi ca sinh vt . Nhng th nghim ny gip xc nh xem nng cht nhim bn trong nc v/hay bn lng c cao gy ra nh hng tc hi cho sinh vt hay khng.

Ni chung, cc th nghim c tnh u c vic thu thp cc mu mt im ca d n, ri gi cho mt phng th nghim c tnh lm th nghim. V chng trnh EEM nh my gi nh trn, chng ta c th thu thp cc mu nc v bn lng 8 trm ly mu v th xc nh c tnh c th c i vi i sng thu sinh mi trng tip nhn. Th nghim c tnh l mt thnh phn hu ch ca cc chng trnh EEM v c th:

- Chng t cht nhim c nh hng sinh hc hay khng- s c mt ca mt cht nhim khng ch ra kh nng c nh hng tc hi i vi i sng thu sinh. Mt


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cht nhim ch c th nh hng c hi nu n xut hin trong mt dng c nh hng sinh hc (tc l mt dng m cc sinh vt c th hp thu).

- nh gi tc ng tng hp ca mi s nhim trong mt mi trng - nhiu khu cng nghip thi ra mt lot cht nhim hn hp c phan trn nhng cht c th c hi trong nc v trong bn lng. Trong nhng trng hp ny, ch ring d liu ho hc thi khng th d bo chnh xc c tnh ca cc cht nhim. Thay vo , ngi ta dng test c tnh o tc ng tng hp ca mi trng b nhim ti cc sinh vt.

- Nu ln c im bn cht mt tc ng c hi test c tnh c th cho bit nng cht nhim c tc ng gy t vong hay cn t vong. Tc ng cn t vong gm c tng trng gim st sc sinh sn suy gim v bin i trong hnh vi.

- Nu c im phn b c tnh ti mt a im test c tnh c th tin hnh trn nhng mu ly t nhiu v tr khc nhau 1 a im, nh cc trm ly mu gn hin trng v xa hin trng ni trn. i vi mc ch chng trnh KTAHMT ca nh my gi nh trn, th nghim c tnh l mt phng php hu hiu m t tn km xc nh qui m c tnh theo khng gian v pht hin ra nhng vng c nh hng mnh ca nc thi.

Th nghim c tnh cp

Mt th nghim in hnh v c tnh cp thng t nhng sinh vt c th vo mt lot mu nc nhim pha long ri ghi li thi gian cho n khi sinh vt cht, thng l 24 n 96 gi. V d cc mu nc thi ca nh my trn c th c th theo mt s nng t 0 n 100%. Kt qu c phn tch bng cch so snh t l phn trm sinh vt cht do nc thi vi s sinh vt t vo mt cuc kho cu kim chng (tc l nc sch hay bn lng khng cha cht nhim). Kt qu phn tch th c tnh cp thng dng xc nh pha long nc thi khin cho 50% sinh vt c th b cht. pha long ny c coi l LC 50 chng hn, hoc nng t vong i vi 50% sinh vt.

i khi, thay v i tm LC50 cho mt sinh vt c th, ta lm th nghim xc nh nng khin cho 50% sinh vt t ra b mt tc ng c th, nh sc ti sinh sn gim st hay b chn vi vo nhng lp bn trong mt khong thi gian nht nh. EC 50, hay nng c tc ng i vi 50% sinh vt c th l gii hn i vi nhng th nghim nh vy.

Thm vo , kt qu test c nh gi xc nh LOEC (nng tc ng thp nht c th quan st c) l pha long cao nht gy ra nh hng c hi ng k v mt thng k. Nng tc ng khng quan st c (NOEC) cng c tnh ra t nhng d liu ny. NOEC l pha long thp nht khng cho thy nhng tc ng c hi ng k v mt thng k.

Th nghim c t mn tnh

Test c tnh mn tnh t cc sinh vt vo mt lot mu nc pha long ca mt mi trng c th, nh bn lng chng hn, v o tc ng cn t vong, v trong vi trng


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hp, c tc ng gy t vong. Tc ng cn t vong c th gm gim tng trng, gim sinh sn, thiu tnh c ng v pht sinh nhng d thng v cu trc. Trong phn tch d liu thng gm so snh trc tip s phn trm tc ng xy ra nhng sinh vt ti im mi trng vi s sinh vt ti mi trng khng nhim. C th tnh c LC50, NOEC v LOEC.

Trong khi vic ngoi suy kt qu test c tnh mn tnh i vi mi trng thin nhin l qu n gin ho, th nhng tc ng cn t vong o c phng th nghim cho thy nhng tc ng tim tng ng k v mt sinh thi xy ra trong thin nhin. V d, s gim st tng trng ca mt loi c c th dn ti gim st sinh sn, kch c nh hn, hin tng n tht nhau tng ln v sc kho tng th ca qun th suy gim. Sc ti sinh sn suy yu c th lm gim quy m qun th v cng c th a ti nhng i thay trong c cu tui ca qun th . Nhng c th c nhng pht trin d thng v cu trc c th nh hng ti qun th v nhng sinh vt c t sut tng trng thp hn, thng l khng c kh nng ti sinh sn.


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bi 4 - nh gi NGUY C SINH Thi

nh gi nguy c sinh thi (ERA) l mt cng c rt hu hiu xc nh tc hi c th v mt sinh thi do mt s n hay mt hot ng (nh vic m rng nh my gi nh ni trn chng hn) gy ra i vi mi trng tip nhn. nh gi nguy c thng l mt phn ca nh gi tc ng mi trng tng th.

ERA l qu trnh d on kh nng v quy m cc tc ng tc hi i vi sinh thi do nhng nhn t tc hi i vi mi trng. ERA l mt cng c quan trng ra quyt nh v mi trng v gip pht hin nhng vn mi trng, thit lp th t u tin v lm cho cung cp c s khoa hc cho cc hot ng. ERA c dng trong rt nhiu tnh hung bao gm:

- nh gi nguy c sinh thi do tnh trng mi trng hin ti gy ra

- D bo nguy c sinh thi do mt phng n pht trin c quy hoch gy ra

- So snh nguy c do cc hot ng pht trin khc nhau gy ra

- nh gi hiu qu cc phng n sa cha khc nhau

- Xp hng cc nguy c do cc nhn t tai ho gy ra t th t u tin nhng hot ng lm gim nh

- Xy dng tiu chun ring cho a im sa cha

Nhng thut ng ch yu dng trong ERA c tm tt Bng 1. Bn thnh phn ca ERA s c cp c th nhng phn sau.

Xc nh vn

Xc nh vn l thnh phn u tin v c l quan trng nht ca ERA, v xc nh phm vi v trng tm nh gi. V mt ny, xc nh vn c dng lm c s cho c qu trnh ERA.

Xc nh vn tin hnh tt th ton b vic nh gi nguy c s thun li v:

- To c hi lin h gia ngi nh gi nguy c v ngi qun l mi trng v bo m vic nh gi nguy c lm ch da cho cc quyt nh qun l.

- Tp trung nh gi nguy c cc cht nhim lin quan, nguy c e do v ch th b e do

- To iu kin cho qun chng tham gia

- Cung cp nhng tiu chun quyt nh r rng cho nhng phng n qun l khc nhau

- Gim tng chi ph nh gi mi trng


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Cn thc hin nhiu bc xc nh vn bao gm tng hp thng tin hin c, nu c im ca a im, pht hin nhn t tc hi v ch th nhn, nu c im ch th nhn v ln m hnh khi nim. Sut qu trnh xc nh vn , cn coi trng vic duy tr quan h hu hiu gia ngi nh gi nguy c v ngi qun l mi trng bo m nh gi nguy c s h tr cho qu trnh ra quyt nh. Trc khi tin hnh ERA, ngi qun l mi trng v ngi nh gi nguy c phi nht tr vi nhau v mc ch tng th, phm vi v thi gian nh gi nguy c.

Bng 1 Thut ng nh gi nguy c

Gii hn nh gi

Nhng b phn hp thnh sinh thi cn c bo v. Gii hn nh gi l nhng tuyn b hay mc ch v mt c im sinh thi (nh nh hng ti sinh sn i vi mt sinh vt thu sinh) cn nh gi hay bo v trong sinh thi . V d, sng Mkng, gii hn nh gi c th l bo v mt ngnh c nht nh.

M hnh khi nim

Mt lot gi thit v cc nhn t tai hi tc ng ti cc thnh phn sinh thi thng c trnh by di dng trc quan vi biu c mi tn ch cc quan h. M hnh khi nim m t sinh thi c kh nng b nguy him, quan h gia gii hn nh gi v gii hn o lng v hng c th dn ti nguy c e do

S c km theo Mt nhn t tc hi tc ng gin tip ti b phn hp thnh sinh thi. V d, vi loi chim u trn doi ct sng trong thi gian di c v thch c nhn thong ng mi trng xung quanh. Nu mt ci cu xy ln ngn tm nhn th chng s ri b vng ny. Nh xy cy cu gn on sng c loi chim thng u khin cho chng b i v tc ng nh mt nhn t tc hi du cho n khng tc ng trc tip ti nhng con chim

Mi e do S c km theo hoc s tip xc gia mt nhn t tc hi v mt vt nhn. Mi e do c lin quan vi kch c v loi nhn t tc hi cng nh s c mt ca vt nhn.

Gii hn o Mt c tnh o c ca sinh thi c quan h vi thnh phn sinh thi c nh gi (Gii hn nh gi). V d nu bo v loi c chp l gii hn nh gi th gii hn o c th l s sng cn hay ti sinh sn ca qun th c chp ti ch

Ch th nhn Mt thnh phn sinh thi (v d c th, qun th, cng ng hay cc sinh thi) c th b nh hng tc hi bi mt nhn t tc hi

Nguy c Xc sut mt tc ng tc hi ti cc thnh phn sinh thi

Nhn t tai hi Bt c thc th vt l, ho hc hay sinh hc no c th c tc ng tc hi i vi mt thnh phn sinh thi (v d c th, qun th, cng ng hay cc sinh thi)


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Tng hp cc thng tin hin c

Din t vn da trn c s thng tin c sn v ngun nhn t tc hi (v d nh my giy v bt giy gi nh trn), c im nhn t gy hi v nguy c h sinh thi b e do. Vic nh gi s b thng tin hin c c lm c s cho vic lp s b m hnh khi nim hoc pht hin gii hn nh gi. Trong trng hp ny, cng bit nhiu loi v lng nc thi cng nh cc qu trnh sinh hc ca sinh vt thu sinh b nh hng ca nc thi th cng xc nh ng hng v cc quan h e do tim tng. Nu thng tin c t th ngi qun l mi trng c th phi ch trng ti vic tng cng kho st c bn trc khi bt tay vo nh gi nguy c.

c im hin trng

y l mt thnh phn quan trng ca xc nh vn v to c hi cho ngi nh gi nguy c hiu bit im nhiu hn. Thnh phn ny gm c nhiu cuc kho st khc nhau gip xc nh phm vi ERA. V d, mt nh gi tnh hnh s dng a im trc y lm r s nhim trong lch s. Thm vo , nu c im s dng t ai xung quanh xc nh xem nhng a im khc c ng gp thm nhng nhn t tc hi cho h sinh thi hay khng.

Xc nh nhn t tc hi

Pht hin nhn t tc hi l thnh phn tip theo ca xc nh vn . Nhn t tc hi l bt c thc th vt l (v d nhng thi qu trong thin nhin hay thit hi ca mi trng sng), ho hc (v d nhng cht v c hay hu c), hay sinh hc c th gy tc ng tc hi i vi mt thnh phn sinh thi. Phn ln cc nh gi nghin cu sinh thi u c quan h vi nhn t tc hi ho hc v phn cn li ca bi hc ny, chng ta s xem xt cc nhn t tc hi c bn cht ho hc. Pht hin cc nhn t tc hi v chng minh c tnh mi trng ca chng s gip la chn thnh phn sinh thi c th b e do, nhng tc ng sinh thi gy ra v mi trng ang quan tm (v d khng kh, t, nc b mt hay nc ngm, m ng vt).

Pht hin v nu c im ch th nhn

Sau khi pht hin nhn t tai hi, tin hnh m t c im nhng ch th nhn c th c. Ch th nhn l mt thnh phn sinh thi (v d, c th, qun th, cng ng hay cc sinh thi) c th b mt nhn t tc hi tc ng. Ch th nhn thng l nhng qun th thc vt v ng vt bn a. Vic la chn ch th nhn da vo:

- Chng chp theo thi gian v khng gian vi cc nhn t tc hi cn quan tm

- Tnh nhy cm tim tng vi nhn t tc hi

- Tnh trng loi c nguy c tuyt chng hoc b e do

- Nhng chim hay c di c ni qun th tp trung

- Tm quan trng v mt sinh thi

- Gi tr thm m hay vn ho i vi cng ng a phng


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- Tm quan trng v gii tr hay thng mi

- Mi trng sng gi tr hoc nhy cm

Sau khi chn xong cc ch th nhn, c th chn cc gii hn nh gi v o lng. Gii hn nh gi l mt thnh phn sinh thi hay ch th nhn c th cn c bo v. V d, gii hn nh gi c th rt quan trng i vi mt loi c c gi tr thng mi trong sng Mkng. Gii hn nh gi c th c c xc nh bt k cp bc t chc no (loi, qun th, cng ng, h sinh thi). Tuy nhin, tr khi mt ch th nhn sinh thi c tn trong danh sch cc loi phi c bo v hay c nguy c tuyt chng, cc gii hn nh gi thng c chn c quan h vi cp qun th hay cp cao hn. Trong nhiu trng hp, phn ng ca cng ng c quan tm nhiu nht. V d, nhng i thay trong cu trc cng ng sinh vt sng y c th l nhng ch bo cho cc tc ng nhim tim tng i vi ton b h sinh thi thu sinh .

Gii hn l mt xch quan trng gia tnh trng ti ch hin ti v mc ch qun l xc lp qua gii hn nh gi. Gii hn o to iu kin o nh lng cc gii hn nh gi. Chng dng xc nh phn ng sinh hc i vi mt nhn t tc hi v c th c ni kt tr li vi cc thnh phn mi trng c nh gi hay vi c tnh c pht hin trong gii hn nh gi . Gii hn o c th c kho st trc tip ti hin trng hay kho cu phng th nghim v bao gm nhng s o v tc ng (v d s t vong, nhng d thng trong ti sinh sn) hay v nguy c e do (v d nng cht nhim trong m). Ly loi c c gi tr thng mi lm v d, mt gii hn o y c th l thnh tu ti sinh sn ca loi c ny.

M hnh khi nim

M hnh khi nim thng l mt bn m t vit c biu trc quan d bo quan h gia cc thnh phn sinh thi vi cc nhn t tc hi e do chng. Mt biu trin khai cc gi thit v cch mt nhn t tc hi c th tc ng ti mt ch th nhn nh th no. M hnh gm c nhng m t kh nng sinh thi b e do v quan h gia cc gii hn nh gi v gii hn o.

nh gi nguy c e do

nh gi nguy c e do l bc th hai trong ERA v l mt thnh phn rt quan trng - khng c s e do th khng c nguy c, nh minh ho Hnh 1. Mi e do l s c km theo hoc s tip xc gia mt nhn t tc hi vi mt ch th nhn. Vic nh gi mi e do m t c im cc nhn t tc hi v xem xt cc yu t nh ngun, quy m, tn s, thi gian v hng e do. Nhng yu t ch yu ca nh gi mi e dc gm c:

- Ngun v s thi cht nhim - xem xt c tnh ca ngun. V d thi cht nhim lin tc, gin on hay chm dt?

- Vn chuyn v tiu hu cht nhim - xem xt c ch vn chuyn cht nhim, qu trnh tiu hu (v d iu g s xy ra vi cht nhim mt khi n c a vo mi trng - bin i, bay hi, hp ph, v ho tan). Hng e do - pht hin


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nhng hng e do c th c i vi mi nhn t tai hi v ch th nhn. Hng e do gm c bn yu t, (v d ngun hay s thi nhn t tc hi, vn chuyn ti mt ni tip xc, tip xc v ch th nhn hp ph)

- Lng e do - lng ho mi e do i vi ch th nhn. iu ny thng c biu din di dng mt liu lng (v d mg/kg/ngy) i vi ch th nhn nh ng vt c v v chim, v di dng nng (v d, mg/kg i vi bn lng v mg/l i vi nc) cho nhng ch th nhn thu sinh nh c v ng vt khng xng sng y.

Sn phm cui cng ca nh gi s e do l d on nng mi trng hay phn b nng tng cht nhim trong mi trng i vi mi ch th nhn quan tm.

nh gi nh hng

nh gi nh hng l bc th ba ca ERA. Bc ny m t quan h gia mt nhn t tc hi vi mt ch th nhn v dng lin kt mt cht nhim vi mt phn ng sinh hc. Thc cht vic nu c im cc nh hng gm c m t nh hng do nhn t tc hi gy ra, lin kt cc nh hng vi gii hn nh gi v nh gi cc nh hng thay i nh th no theo cp bin i ca nhn t tc hi. S ni kt ny thng c lm qua nghin cu ti liu v s liu c tnh hoc qua vic tin hnh nhng th nghim c tnh c th ti ch, nhng cng c th c cch lm khc.

Sn phm cui cng ca nh gi nh hng l nng e do cao nht hoc s phn b nhng nng e do cao nht cho mi cht nhim khng dn ti nh hng sinh thi qu sc chu ng i vi tng ch th nhn.

Nu c im nguy c

Nu c im nguy c l giai on cui cng ca ERA to iu kin cho ngi nh gi nguy c lm sng t quan h gia cc nhn t tc hi vi nh hng v cc thc th sinh thi. C th i n kt lun v s xut hin mi e da v tai ha ca nhng nh sinhhng thy trc. Vic nu c im nguy c kt hp kt qu nh gi mi e do vi nh gi nh hng nh gi kh nng nh hng tc hi s xy ra do nguy c trc nhn t tc hi v mc ca nh hng. Vic nu c im nguy c c ba bc:

1. Tnh ton d on v nguy c

2. Phn tch tnh khng chc

3. Gii on tm quan trng i vi sinh thi

Hnh1. iu kin nguy c sinh thi

e do Ch th nhn

Nguy c

Ri ro


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c on nguy c

C th c on nguy c bng cch dng mt s phng php v k thut. Mt k thut l phng php h s thng c dng cho nhng cht nhim n l v hng e do vi mt vt nhn n l. C th dng phng php ny pht hin tn ti ca mt nguy c tim tng, ch khng phi l mc hay xc sut. Phng php h s i hi phi phn chia nng mi trng d tnh (EEC) hoc nng e do ca ho cht bng mt nng chun ca cc nh hng (BC) c c mt tr s. Tr s thu c c cng nhn l mt h s nguy him (HQ) hay h s nguy c v c trnh by trong cng thc sau y:

HQ EECBC

=

C th o trc tip hoc d bo EEC t cc m hnh nguy c mi trng. Cc chun l cc ngng nng cht nhim trong mt mi trng nh nc b mt hay m c, chng hn, n c coi l an ton, cn di na th nh hng tc hi khng lng c. Cc chun c th ca mt a im c th c xc nh trong nh gi nh hng, hoc cc chun bo v mi trng mt loi c th do cc c quan nh nc thit lp v p dng cho mi d n v hot ng c nh hng tc hi tng t. Cc cp nh hng chp nhn c cn c la chn qua tham vn nhng ngi qun l mi trng trong qu trnh tin hnh xc nh vn . Ni chung, nu HQ nh hn 1, a im c th xp vo loi nguy c thp v khng cn phi tip tc thm na. Nu HQ ln hn 1 nh vy l c nguy c, v cn tip tc phn tch thm.

Phn tch tnh khng chc

Phn tch tnh khng chc c coi l yu t ch yu th hai ca vic nu c im nguy c. Phn tch tnh khng chc pht hin v lng ho tnh khng chc trongcc nh vn , trong nh gi e do v nh hng v trong nu c im nguy c v gip ngi qun l mi trng thy r ch mnh v ch yu ca ERA. L hng ln v kin thc c th dn ti ch cc tiu ch v chun chp nhn c t ra qu thp n ni khng bo v c cc thnh phn sinh thi. Ngc li, nu thiu d liu thch ng th cc chun s c t ra qu cao n mc vic x l nc thi qu tn km. Kt qu ca phn tch tnh khng chc i vi ERA v nu ra nhng cch gim bt tnh khng chc . Nhng ngun chnh ca tnh khng chc c tm tt Bng 2.

Tm quan trng sinh thi

Vic gii on tm quan trng ca d on nguy c i vi sinh thi cn da vo nhn xt ca cc chuyn gia v to iu kin cho lin kt d on nguy c vi trao i kt qu nh gi. N cn xem xt bn cht v tm quan trng ca cc nh hng, phn b nh hng theo khng gian v thi gian, v kh nng hi phc khi nhn t gy hi b loi tr. Vic gii on tm quan trng i vi sinh thi cn c mt cuc tho lun v nhng cu hi sau:

- Loi no c th b nguy nht?


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- Nguy c xut hin vo thi im no trong nm?

- Nguy c tri u c vng hay c nhng im nng vi nguy c cao hn?

- Cht gy nhim di chuyn nh th no t ni thi ti cc ch th nhn? (v d nc mt, di chuyn ca nc ngm, dy chuyn thc phm t t?)

- bit g v sinh thi, sinh hc hay hnh vi mt loi b e do c th b tc ng (tc l gim nh hay tng) ti nguy c ny?

- C nhng giai on no ca i sng sinh vt b nguy c e do hn giai on khc khng?

- Liu c loi no ng lo hn do chng to ra mi trng sng hay c mt ngun thc n cho mt loi quan trng ang quan tm khng?

- Nhng l hng kin thc v d liu no l vt chng ngi cho vic d on ng nguy c?

Bng 2 Cc nguyn nhn chnh ca tnh khng chc

Vng tnh khng chc Yu t tnh khng chc

Xc lp m hnh khi nim Sn phm xc nh vn

Nhng gi nh sai kh pht hin, lng ho v loi b

Thng tin v d liu Dng d liu hay thng tin khng y

Da vo nhn xt hay gi nh ca chuyn gia

Tnh ngu nhin (tnh bin thin t nhin)

c im c bn ca nhn t tc hi v ch th nhn

C th c tha nhn v m t nhng khng loi b c

Ph thuc vo phn tch nh lng

Sai s Do thit k thc nghim, o c, quy trnh ly mu hay do qu trnh xy dng m hnh m phng

Gim c bng nn np tt ca phng th nghim, cc quy nh, phn tch nhy, hiu chnh v so snh m hnh v kim nh hin trng

Qun l nguy c

Khi hon thnh ERA, ngi qun l mi trng v ngi c thm quyn ra quyt nh ca cac c quan chnh quyn phi c quyt nh v nhng phn sinh thi b lm nguy, v gi tr ca chng v v ph tn (tc l c tin bc ln nhng li ch khc) do bo v c hay khng bo v c nhng ti nguyn . Khi kt lun, ngi qun l mi


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trng phi xem xt khng ch kt qu nh gi nguy c m cn c nhng vn x hi, kinh t v chnh tr na. thun li cho vic ra quyt nh cn c nhng thng tin sau y:

- Mc ch ERA

- Lin kt gia gii hn o v gii hn nh gi

- Mc v phm vi nh hng, vn v min xung t chnh thng thy trong qun l ti nguyn v qun l mi trng. Thng tin c gi tr v sinh thi c cung cp phi gm c nhng iu cn nhc v khng gian v thi gian v nu c th c kh nng hi phc.

- Nhng gi nh c s dng v tnh khng chc trong qu trnh nh gi nguy c

- c trng tm tt ca cc cp nguy c cng nh phn tch trng s cc bng chng

- Kh nng thm nguy c t nhng nhn t tc hi khc vi nhng nhn t xem xt (nu c th)

Nu c p dng ng n, ERA l mt cng c c lc trong qun l mi trng tng hp v nh gi tc ng mi trng cung cp mt hng tip cn v mt khun kh chun ho phn tch nhng vn sinh thi. N cng cp n tnh khng chc. Kt qu ERA rt qu i vi ngi ra quyt nh v h ng trc s la chn kh khn phi i bao nhiu phn ti nguyn cho nhng li ch kinh t v x hi d tnh trong nh gi mt d n hay hot ng.


cong cu khoa hoc va ky thuat danh gia tac dong moi truong p1 558

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