KY YEU "CAC 0£ TAl NGHIEN CUU KHOA HOC

KY YEU "CAC 0£ TAl NGHIEN CUU KHOA HOC- CONG NGHg NGANH TAl NGUYEN VA MOl TRUONG GIAI DOAN 2002-2006"

DETAI: N G H I E N CLTU D A C D I E M D I A H O A C A C C H A T C H I T H j D A N H D A U P H A N TU* N H A M D I N H H U O N G D A N H G I A T O C D O L A N G D O N G T R A M T I C H , C H A T L U O N G V A N G U O N G O C 6 N H I E M

M O I T R U O N G T R A M T I C H M O T S O V U N G C U A S O N G V A C A N G B I E N L O N B A C T R U N G B O V I E T N A M ( T H A N H H O A - H A T I N H )

C o q u a n chu t r i : Lien doan Dia chat bien

C h u n h i e m De t a i : KS. Bui Quang Hat, Lien doan Dia chat bien Can bp t h a m gia nghien curu:

KS. Le Van Ddc Lien doan Dia chat bien KS. Le Thi Ha Lien doan Dia chat bien KS. Ly Viet Hiing Lien doan Dia chat bien KS. Pham Thi Nga Lien doan Dia chai bien

GS. TS. Mai Trong Nhuan Trudng Dai hoc Qudc gia Ha Ndi KS. Dinh Van Tu Lien doan Dia chai bien

Muc tieu nghien ciru

- Xac dinh toe dp ldng dpng tram tich cac cua song, cang bien su dung trong nghien cuu trdm tich va danh gid muc dp san lap lupng lach cua song, cang bien.

- Nghien cuu to hpp dong hanh mpt so' chi thi danh da'u phdn tit va nguyen to' k i m loai nang nhdm xac dinh miic dp va nguon goc gay 6 nhiem de quan ly bao ve m o i trudng.

Nhidm vu cua de tai

- Thu thap, phan tich tong hop tdi lieu hien co.

- Khao sat lay mdu va x u ly mdu.

- Phdn tich mdu.

- Luan giai ket qua va viet bao cao thuye't minh.

Tom tat ket qua nghien curu

I. PHUONG PHAP LUAN V A PHUONG PHAP NGHIEN CUU L I . Phuong phap l u a n

Trong vdi thap ky vita qua, 6 nhiem cac hpp chdt co clo ben vung da thu hut su chii y cua nhieu nhd khoa hoc tren the gidi do chinh kha nang tich luy sinh hoc manh, dpc tinh cao ddi vdi con ngudi va cdc loai sinh vat sdng, dac biet la anh hudng den chdc nang npi tiet. cung nhu tac dpng xau den mPi trudng va he sinh thai. Cac hpp chat polyclobiphenyls (PCBs) bao gdm: cac hpp chat chinh la: 2-C1, 3-C1, 4-C1, 5-C1, 6-CL, 7- Cl, 8-C1 dupe su dung trong viec lam lanh cac thiet bi dien nhu dau bien the,... .Hop chat organochlorine pesticides (OCPs) thanh phdn bao gdm cdc hop chat chinh: Lindane (p*- H C H , .y-HCH, ct-HCH), D D T , D D E , D D D , 666, Dieldrin, Endrin aldekyde, Heptachlo, Andrin. Chung dupe su dung vao cudi nhung nam 1950. Do tinh ben vung tuong ddi cao,

KY YEU "CAC BE TAI NGHIEN CUU KHOA HOC- CONG NGHE NGANH TAl NGUYEN VA MOl TRUONG GIAI BOAN 2002-2006"

cac hop chat PCBs va OCPs da duoc tfch luy nhieu trong cac m o i trucmg khac nhau (trdm tich, nuoc, sinh vat...) va ddu co nguon gdc t d luc dia. Do do, viec nghien cuu cac ngudn 6 nhidm va kha nang tich luy cac hop chat co clo ben trong m d i trudng vung duyen hai la rdt quan trong, dac biet la cdc nude chau a dang phat trien. Song song vdi viec quan trdc, phdn tich, danh gid su phan bd va mdc do 6 nhidm m o i trucmg do cac hop chdt huu co co clo bdn vung (PCBs, OCPs,...), ngudi ta con cd the sd dung cdc chdt chi thi nay de danh gia tdc do ldng dong tram tich. Trudc ddy, dd xac dinh tdc do ldng dong tram tich, cac nhd khoa hoc tren the gidi thucmg phai sd dung bang phuong phap ddng v i phdng xa nhu l a :^{2 1 0} P b ,^{1 3 7} Cs,... phuong phap nay ddt tidn va chi phi rat tdn kem.

Hien nay phuong phap danh dau phan tu dua vao cdc hop chat co clo ben da dupe dp dung rpng rai trong nhidu linh vuc nghien cuu khdc nhau nhu trdm tich, dia hda, sinh hoc, hda moi trudng, 6 nhidm m d i trucmg. Tai vung them luc dia Sanpedro (Nam vinh Los Angeles) ngudi ta da su dung phuong phap chi thi danh dau phdn t d de xac dinh ngudn gdc, dac diem phan bd cac chat d nhidm trong nude va tram tich den dp sdu 500m nude, d vinh Tokyo (Nhat Ban) cac nha khoa hoc da nghien cuu cac chi thi nhu L A B (Linear alkylbenzenes), PCBS de xdc dinh ngudn gdc cung nhu phuong thdc van chuydn chung...d bien Bde va bidn Baltic, cdc nha nghien cuu da su dung phuong phap nay trong viec xac dinh ngudn gdc d nhidm ddu...

Ci nude ta, phuong phap nghien cuu xac dinh tdc dp ldng dpng trdm tich da dupe mpt sd nha khoa hoc dp dung va mang tinh thuc tidn cao nhu: vung bidn ven bd cda s6ng Cuu Long cd tdc dp ldng dpng trdm tich cao so vdi toan ddi bien ndng ven bd Viet Nam.

Le Xuan Thuyen da xac dinh tdc dp ldng dpng tram tich bdng phuong phap ddng v i P b^{2 1 0} tai viing vinh Nam Can va rung ngap man Ca M a u la 0,4-0,7 cm/nam. Bang phuong phap chi thi danh ddu phdn tu, V u Trucmg Son da xdc dinh tdc dp ldng dpng trdm tich d khu vuc: cda Cung Hdu la (4-4,75cm/nam), d cua Ba Lai (3,5-4,0cm/nam). GS. M a i Trpng Nhuan, TS. Dao M a n h Tien da xdc dinh dupe tdc dp ldng dpng tram tich d vung bidn Khanh Hda (1-1,75 cm/nam). Dac biet tai khu vuc cda Ba Lat (sdng Hdng), trong chuong trinh hpp tdc nghien cuu ve dac diem dia chat m d i trudng va danh gia tdc dp ldng dpng tram tich d cua Ba Lat, giua trudng Dai hoc Qudc gia Ha N p i va Ha Lan. Trong cong trinh nay GS.Mai Trpng Nhudn da su dung 4 phuong phap dd xac dinh tdc dp ldng dpng trdm tich (Phuong phap ddng v i P b^{2 1 0}; phuong phap chi thi danh ddu phan td; phuong phap ddng epe quan trdc; phuong phdp bdy trdm tich). Toan bp cac ket qua tren cho thay tdc dp lang dpng tram tich la tuong duong nhau: khu vuc ddng bdng sdng Hdng tai cda Ba Lat cao nhdt d rdng ngap man (5,6 cm/nam) va thap hon d khu vuc ngoai cda sdng Hdng (4,5 cm/nam). Chinh v i vay chung toi chon phuong phap nay v d i mong mudn giai quyet hai van de chinh: danh gia tdc dp ldng dpng trdm tich vd xac dinh ngudn d nhidm trong trdm tich.

1.2. Phuong phap nghien cuu

- Thu thdp va tdng hpp cac tai lieu

- Cac phuong phap nghien cuu ngoai thuc dia

a. Mang ludi va phuong phap khao sat: mdu dupe lay k h u vuc trong song tram each tram 0,3-0,5km; bien ven b d mang ludi khao sat la 0,8- 1,2km. L p trinh khao sat dpc bd bien, cda bien thu thdp tai lieu ve dia chat, dia mao, trdm tich... Khao sat tren bien bdng thuyen tien hanh quan sat, do sau hdi am, thu thap cac thong tin phuc vu nghien cuu dia hda moi trudng.

KY YEU "CAC BE TAI NGHIEN CUU KHOA HOC- CONG NGHE NGANH TAI NGUYEN VA MOl TRUONG GIAI BOAN 2002-2006' ^

b. Thiet bi khao sat: doc bai trieu va cua song ven bien co thd di bp hoac dung

thuyen nho de di chuyen; m i u tram tich dupe lay tren mat, bang dng hut piston tay. Tren bien sir dung thuydn 10-45 C V khao sat d dp sau 0-10m nude. Thiet bi lay m i u gdm: dng hut piston tay, cudc dai duong. dng phdng. D i n h v i d i n dudng: may Garmin

c. Cach lay miu: m i u la'y tai cac v i t r i cd che dp tram tich tuong ddi dn dinh, cd kha nang tang tru cac chat bao ve thuc vat, xang ddu, cha't thai cua tau thuyen, theo mat cat theo ddng chay dpc cua song ra bien, hoac bai tridu cd cay ngap man. M a u lay tai v i t r i ma tram tich cd thanh phan bun set hoac bun sdt l i n cat, d dp sau l - 2 m nude. Tai cac v i tri la'y mau chi thi danh dau phan t u ddu lay mdu dp hat, m l u phan tich cac chi tieu m o i trudng. Cot mau la'y g i u nguyen dng nhua va bpc k i n ni long chuyen ngay ve phdng thi nghiem. M a u phan tich cd thanh phan tram tich chu yeu la bun set va dupe chon theo chieu sau cot m i u , khoang each giua cac m i u la 0,3-0,5m/miu.

Cac phuong phap phan tfch miu

- PCBs, OCPs: su dung phuong phap phan tich sac k i k h i (GC-14B).

- K i m loai nang: phan tich tren cac thiet bi quang phd hdp thu nguyen tu, hdp thu phan tu hoac phuong phap dien hda theo qui trinh rieng biet cua cac nguyen to.

Cac phuong phap xu ly sdlieu: cdc ket qua phdn tich mdu, x u l i , thd'ng ke, lap mat cdt, so sanh, danh gid ket qua vd luan giai: dac diem phan b d theo hudng ddng chay song ra bidn cua PCBs, OCPs, va cac k i m loai nang; su phan bd cdc OCPs, PCBs va k i m loai nang theo chidu thang ddng; Didu tra xdc dinh thdi gian gay 6 nhidm PCBs, OCPs; Dua vao viec ddng hanh o nhidm PCBs, OCPs vdi cdc k i m loai nang de xac dinh ngudn gdc d nhidm, tien tdi dd xua't quan ly m o i trudng;

Theo dp sau cot mdu va thdi gian gay o nhidm PCBs, OCPs tinh tdc dp ldng dpng tram tich.Tdc dp ldng dpng tram tich dupe tinh theo phuong phap sau :

PCBs va OCPs dupe su dung rpng rai va thai ra m o i trudng t d nhung nam dau cua thap ky 60. Do dac tinh ben vung va tich luy cua PCBs, OCPs nen sau k h i su dung (trong ddu bien the, nong nghiep), chung dupe giu lai trong m o i trucmg dat, nude va theo ddng chay tdi cac cda song vd bien. V i vay. qua trinh tich luy PCBs, OCPs trong trdm tich ven bd dupe tinh khoang 40 nam. Tdc dp tich luy cua hda chdt trong tram tich dupe tinh bang ty so giua chidu day tram tich ldn nhat cd chda ham lupng PCBs, OCPs (cd dau hieu duong tinh) vd thdi gian su dung (thdi gian tdn tai trong m o i trudng).

ARQCPS (cm/nam) = DocP s (cm) / A TO C P s (nam) A R , ^ (cm/nam) = DpcB s (cm) / ATpcB s (nam)

Trong dd : AR (accumulation rate) la tdc dp tich luy trong tram tich; D (depth) la

chidu day cue dai cd chua PCBs, OCPs va A T (accumulation time) la thdi gian tich luy trong tram tich cua PCBs, OCPs. Tdc dp ldng dpng trdm tich SR (sedimentation rate) dupe coi la ldn nhdt cua A R0c ps vd ARpc^.

KY YEU -CAC BE TAI NGHIEN CPU KHOA HOC- CONG NGHg NGANH TAI NGUYEN VA MOl TRUONG GIAI DOAN 2002-2006"

Khdi luong miu phan tfch dupe thi hien trong bang sau:

STT Cdc loqi mdu K h u vuc Sd luong (mau)

STT Cdc loqi mdu K h u vuc

D u kien Thuc hien

1 Phan tfch do hat Cang Nghi Son 19 19

1 Phan tfch do hat

Cua Hoi (song Lam) 21 21

2 Ion kim loai nang 15 chi tieu Cang Nghi Son 19 19 2 Ion kim loai nang 15 chi tieu

Cua Hoi (song Lam) 21 21

3 Phan tfch ham luong PCBs, OCPs

Cang Nghi Son 19 19

3 Phan tfch ham luong PCBs,

OCPs Cua Hoi (song Lam) 21 21

II. KET QUA CUA DE T A I

a. Phuang phap nghien cdu dac diem dia hoa cac chat chi thi danh dau phan tu nham dinh hudng danh gia tdc dp lang dpng tram tfch, chat lupng va ngudn o nhidm moi trudng tram tich mpt sd vung cua song va cang bien la cd ca sd khoa hoc va mang tinh thuc tidn cao, co the ap dung cho tat ca cac vung cda song va cang bien.

b. Gia tri Eh, p H Vung cang Nghi Son

Gia tri p H dao dpng: 7,72-8,25, trung binh dat 8,02; gia tri Eh trong vung dao dpng trong khoang: 151-173mV, trung binh la 159mV. V d i chi so p H va Eh tren, moi trudng tram tich vung nghien cuu dac trung bdi: moi trudng kiem yeu - oxy hoa manh (7,5 < pH

< 8,5; 150mV < Eh < 173mV), vdi thanh phan tram tfch chii yeu la bun set mau xam, xam nau, xam tdi.

Vung cua Hpi

DP p H trung binh dat 7,59, dao dpng trong khoang 6,68 - 7,85, cac gia tri nay dac trung cho moi trudng trung tfnh - kiem yeu, phan anh m o i trudng cua song ven bien chiu anh hudng nhidu ngudn tram tfch td luc dia mang ra. Eh cd gia tri trung binh 91,23mV, dao dpng td 59mV den 143mV, dac trung cho moi trudng oxy hoa yeu (bang 5.2).

Dua vao chi sd p H va Eh, trong viing nghien cdu cd the xac dinh dupe 2 kieu moi trudng tram tfch sau:

+ M o i trudng trung tinh - oxy hoa yeu (6,5 < p H < 7,5; 4 0 m V < E h < 1 5 0 m V ) phan bd d cac khu vuc: trong cda H p i va phia Dong, Dong Bac ngoai khoi cua H p i ; thanh phdn trdm tich chii yeu la bun set giau mun ba huu ca.

+ M o i trudng kidm yeu - oxy hod yeu (7,5 < p H < 8,5; 4 0 m V < Eh < 150mV) chiem uu the trong todn viing bien ven bd (0-10m nude).

c. Cdc nguyen td Mn, Cu, Pb, Zn, As cd ham lupng trung binh thap hon ham lupng

trung binh cua chinh nd trong trdm tfch bien nong The gidi ( T d < l ) ; Sb cd ham lupng trung binh xap x i vdi ham lupng trung binh trong trdm tich bien nong The gidi ( l < T d < l , 7 ) . Do vay. cac nguyen td tren khong cd nguy co gay o nhidm. Thuy ngan la nguyen td gay o nhidm trong moi trudng tram tich (Td>3). Ham lupng nguyen td H g tdn tai ddng hanh ciing cac hop chat PCBs va OCPs va cd xu hudng giam ddn theo chidu sau cot mdu tram tich.

KY YEU "CAC BE TAI NGHIEN CPU KHOA HOC- CONG NGHE NGANH TAl NGUYEN VA MOl TRUONG GIAI BOAN 2002-2006" ^

d. Ham luong cac hpp chat PCBs va OCPs co xu hudng giam dan tu song ra bidn.

Theo chieu sau cot mau trdm tich cac hpp chat OCPs va PCBs co ham lupng tang cao d dp sau 30-40cm sau do chiing giam dan theo chieu sau.

e. Bang phuong phap chi thi danh da'u phan t u budc dau du bao tdc dp lang dpng tram tich d cac khu vuc cua song nhu sau:

- Hai Thupng khoang: 1,35cm/nam - Hai Ha khoang: l,5cm/nam - Cua Bang khoang: 2,25cm/nam - Cua H p i khoang: l,95cm/nam

- Song L a m (Xuan Dan-Xuan H p i ) khoang: 2,05cm/nam.

f. Trong trdm tich co bieu hien o nhidm H g d khu vuc cac cda song: Hai Thupng, Hai Ha va cda Bang, ngoai cda H p i , Tay Bde Hon Ngu. Ngoai ra, con cd bieu hien o nhidm D D T tai khu vuc: Hai Thupng, Hai Ha, Xudn H p i , Xuan Trudng; D D E tai Xuan Trudng; D D D tai Xuan H p i va PCBs tai Hai Thupng. Nguyen nhan gay 6 nhidm cua H g va cac hpp chdt OCPs, PCBs cd hen quan chu yeu tdi cdc hoat dpng nhan sinh.

g. Thdi gian OCPs ( D D T ) gay d nhidm trdm tich tai H a i Thupng va Hai Ha xdp x i 15 nam, tuong dng vdi thdi gian td nam 1990 cho den nay. Thdi gian OCPs ( D D T , D D E ) gay o nhidm trong trdm tich tai Xuan Trudng la 25nam, tuong ung vdi thdi gian td 1965- 1990. Khoang thdi gian OCPs ( D D T , D D D ) gay o nhidm tram tich tai tai Xuan H p i xdp x i 20 nam tuong dng vdi thdi'gian t d 1975 den 1990.

h. Dd xua't hudng su dung hpp ly tai nguyen thien nhien va bao ve m d i trudng

Vung cang Nghi Son va cua H p i ndm trong khu vuc Bde Trung Bp Viet Nam, la mpt trong nhung vung trpng diem kinh te cua qudc gia cd ngudn tai nguyen da dang; nen cdn cd nhung hudng sd dung va bao ve mpt edeh hpp ly ngudn tai nguyen dd phat tridn bdn vung.

Trong vung cd cac ddng bdng ven song bien thudng xuyen trdng cdy luong thuc va canh tdc thdm canh qua nhidu vu; lupng phdn bdn huu co, hda hoc cung vdi lupng thudc bao ve thuc vat, thudc trd cd, trd nam dupe dua vao sd dung. Vie*c sd dung thudc trd sdu d nude ta ngay cang gia tang trong cdc thap k y qua; theo ket qua thdng ke gdn day 90% ddt nong nghiep cd su dung thudc trd sau. Cac loai thudc t r d sau dupe sd dung bao gdm:

phosphat huu co, clorua huu co, thuy ngan huu co,... Dac biet mpt sd loai thudc da dupe Nha nude cam su dung nhung cd the vdn tiep tuc dua vao sd dung nhdm phuc vu cho nhung lpi ich rieng. Trong san xudt nong nghiep, viec su dung cac thudc t r d sau, cung v d i qua trinh xdi mdn ddt cd chda thudc trd sau cd the gay anh hudng mpt each nghiem trpng tdi cac he sinh thai tai vung cua song va ddi bd nhay cam, gdy t u vong cac cd thd, quan the sinh vat. Cudi cung, thudc tru sau tich luy dan vao chudi thdc an, la cac loai sinh vat ma con ngudi tieu thu, no gay nguy hiem cho sdc khoe con ngudi. T d qua trinh hoat dpng san xua't cPng-nong nghiep cua con ngudi, du lupng thudc trd sau xam nhap vao nude va trdm tich trong vung gay nen nhung nguy co 6 nhidm m o i trudng trong khu vuc. D o dd viec giao due nhdn thdc ngudi dan ve luat bao ve m o i trudng la vd cung quan trpng. Cdn nghiem cam su dung cac loai thudc bao ve thuc vdt ndm trong danh muc da dupe Nha nude ban hanh. Han che su dung tdi mdc tdi da, cdn dp dung nhung cdng nghe khoa hoc mdi vao san xuat (cong nghe sach, cdng nghe v i sinh...).

Q KY YEU "CAC OE TAI NGHIEN CUU KHOA HOC- CONG NGHg NGANH TAI NGUYEN VA MOl TRUONG GIAI SOAN 2002-2006"

He sinh thai rung ngap man phat trien a vung cua song ven bien doc theo cira Bang,

phia Tay cang Nghi San va song Lam. Rung ngap man duac coi la he sinh thai co nang suat sinh hoc cao, la nai cung cap chat dinh duang cho nhieu chu6i thuc an, la nai sinh san va nuoi duang nhidu nguon sinh vat. He sinh thai rirng ngap man ( R N M ) con duoc coi la vung dem giua bien va dat lien. R N M co tac dung didu hda khong k h i trong vung, chdng xdi l d va phat trien bai bdi ven bien va la ngudn gidng torn, cua, ca rat phong phu.

R N M la nai cu tru cua loai chim va cac loai dong vat khac. N d la mot dang tai nguyen thien nhien cd kha nang tai tao cao. Hien nay R N M dang bi suy thoai do qua trinh lam dam nuoi torn ca, san lap mat bang de xay dung nha d, khu du lich. chat pha va canh tac dat nong nghiep, xay dung mot sd cong trinh kien cd nhu cang bidn. Do vay, can ket hop giua san xuat nong nghiep va ngu nghiep mot each hop ly. Can bd sung trdng rdng, td chuc tuyen truyen cac chuang trinh moi trudng, giao due bao ton thien nhien de nang cao nhan thdc nhan dan ve gia tri sinh thai R N M . Cd cac phuang an qui hoach su dung dat dai can duac thdng nhat giua cac nganh. Thiet lap viec quan ly va sd dung dat dai dd duy tri theo dung muc dich trong qui hoach. Can cham sdc R N M hien cd, tai sinh tu nhien rung ngap man, tang cudng trdng rung bd sung tren cac bai bdi m d i hinh thanh va viing bien cd do man cao, ngap sau va tac dpng cua sdng manh.

Ngudn lpi sinh vat bien trong vung nghien cdu la rat phong phu vdi cac loai ca, torn, cua, muc, hau, so trai... Hien tai trong viing bien nhu: Hai Ha, Hai Binh, Nghi Son, Xuan Hpi, Xuan Trudng, Xuan Dan, Xuan Phd, Xuan Hai cd rat nhieu phuang tien su dung danh bat hai san dang hoat dpng nhu thuyen (cong sudt < 2 0 C V ) , ludi mat nhd danh bat d ven bd, cac thuyen cd cong suat 20-600CV dung danh bat xa bd va van tai hang hda tren bien. Cac hoat dpng danh bat tap trung chu yeu vao cac vung nude nong ven bd. K y thuat va phuang tien danh bat lac hau, nguy hiem va gay huy diet, ma phai phai ke den day la viec su dung ludi mat nhd va chat nd. Cac chat thai do phuang tien cu ndt thai ra bien nhu PCPs (dau lam mat dpng ca) va Pb (trong xang). Do vay, dia phuang cung cac ca'p, nganh lien quan can cd nhung luat bao ve ngudn tai nguyen: cam danh bat hai san bang ludi mat nhd va su dung danh ca bang m i n ; tu sua nang cap cac tau thuyen cu ddng mdi tau thuyen mdi phuc vu danh bat xa bd; giao due nhan thuc nhan dan trong vung ve ngudn tai nguyen moi trudng.

Nghe nuoi trdng thuy-hai san, lam mudi cung dang phat trien kha nhanh tai cac khu vuc: cua Bang, Nghi Son, dpc hai ben bd cua H p i . Cac hoat dpng kinh te nay tuy mang lai lpi ich trudc mat cho dan dia phuang, nhung ve lau dai se lam anh hudng tdi moi trudng sinh thai khu vuc nhu: phen hoa, nhidm man, mat quy dat do viec bd hoang cac dien tich nuoi trdng kem hieu qua va lam mudi; o nhidm m o i trudng nude va tram tich bdi lupng thdc an thua trong nuoi trdng thuy-hai san. Ben canh dd, viec chat pha rung ngap man tai cac viing cua song ven bien nham tang dien tich nuoi trdng thuy-hai san va lam mudi dang didn ra kha manh, da gay ra xdi l d bd song, mat quy da't, lam mat noi d va da dang sinh hoc cua mpt sd loai. De nuoi trdng thuy san - lam mudi ket hpp vdi bao ve moi trudng sinh thai mpt each hieu qua, can phai cd nhung quy hoach cu the nham ket hpp giua nuoi trdng thuy-hai san, phat trien rung ngap man.

Giao thong van tai: trong vung cd cac cang (cang ca cda Bang, cang nude sau Nghi

San, cang ca Nghi Son, cang Son Phd, cua H p i va hai cang quan dpi) la nai co nhieu tau thuydn ra vao trao ddi hang hoa va neo dau tau thuyen. Hang ngay lupng tau thuyen nay da thai vao moi trudng trong khu vuc mpt khdi lupng ldn xang dau va dau thai tu cac dpng ca. Nhin chung. so lupng tau cd hang chuc nghin tan trd len, cac tau chuyen dung

KY YEU "CAC OE TAI NGHIEN CUU KHOA HOC- CONG NGHg NGANH TAl NGUYEN VA MOl TRUONG GIAI DOAN 2002-2006'

va cac tau hien dai chua nhidu. Phan Ion la cac tau co trong tai nho, trang thiet bi con lac hau. Do do, nganh van tai bien can phai dau t u phat tridn nhanh va toan dien, vd co sd vat chat ky thuat, dich vu cang, dpi tau, cdng nghiep ddng sua chua tau, dich vu hang hai.

Tai nguyen khoang san bien: hai tinh Thanh Hda va H a Tinh cd cac m d titan tai Quang Xuong, Cam Xuyen, K y A n h vdi tru lupng ldn (hien tai k h u vuc cua H p i cd x i nghiep tuyen va che bien quang titan). D o vay viec khai thac va che bien phai tuan thu diing theo phap luat bao ve m o i trudng ma Nha nudc da ban hanh, can co nhung danh gia tac dpng moi trudng ddi vdi nhung vung san xuat va che bien quanh md.

Tai nguyen du lich bien: vung nghien cdu cd rat nhidu danh lam, thang canh, cac khu du lich sinh thai Nghi Son, cua H p i , cua H p i - Hon N g u cung vdi cac bai tdm thoai dep. Cac hoat dpng du lich tai day con thieu nhung qui hoach cu thd, co sd ha tdng con so sai, quan ly cdn yeu kem. Ben canh dd Id do phong tuc tap quan cua ngudi dan va y thdc bao ve moi trudng chua cao. Trong qua trinh khai thdc bai tdm nay sinh ra lupng chat thai, rac thai (nilon, vd hpp, chai lp...) ra bai tdm dpc bo bien. Ngoai ra, ddn dia phuong cung vdi qua trinh qui hoach khu du lich con chat pha rdng chdn gid lam chat ddt va mat bdng xay dung nha nghi, khach san. D o vay, chinh quyen dia phuang va cac cdp cdc nganh cdn cd quy hoach cu the nhdm phat trien du lich sinh thai di ddi v d i trdng rung, tuyen truyen van dpng giao due m p i ngudi bao ve m o i trudng.

Trong vung cd nha may x i mang Nghi Son vdi he thdng day chuyen x i mang keo dai ra bien, cung vdi cdc nhd may, khu cdng nghiep phat trien dpc hai bd song L a m la ngudn thai ra cdc chat thai cong nghiep vao m o i trudng. V i vay, hang nam phai tien hanh danh gia tac dpng moi trudng tai nha may, cac khu cong nghiep nhdm k i e m soat ngudn d nhidm, va tuan thu theo cac npi quy, quy dinh ve tieu chudn 6 nhidm da ban hanh.

Da cd bieu hien 0 nhidm tram tich bdi H g va cac hpp chdt (PCBs, OCPs), cu the nhu sau: H g tai cac cua song (Hai Ha, cua Bang), ngoai khoi cda H p i , Tdy Bde hdn Ngu; D D T tai Hai Ha, Hai Thuang; D D E tai Xuan Trudng; D D D tai Xuan H p i ; PCBs tai Hai Thupng, nude va rac thai tai cua H p i va cda Bang. Trong nude bien tai cua H p i va cda Bang cd nhidu huydn phu, dp thau quang kem, cd bidu hien d nhidm bdi ddu va rac thai.

Khu vuc ngoai khoi cua H p i va cang Nghi Son nude bien kha sach, tuy nhien tai mpt sd khu vuc (trong cang N g h i Son, cua sdng phia Tdy cang N g h i Son) vdn con cd nhung vang ddu. Qua khao sat thuc te va tai lieu thu thap dupe tai khu vuc trong sdng cho thdy dp p H cua nude song tai day thdp hon cac khu vuc khac, ham lupng c o l i f o r m cao, mpt sd khu vuc gdn cang nude cd m u i hdi thdi. Nguon gdc gay o nhidm tai day chu yeu la t d cac hoat dpng nhan sinh nhu: san xudt va su dung phan bdn, thudc trd sau, giao thdng van tai, dd xa rac va nude thai, khai thac md, nuoi trdng thuy-hai san,...

0 Viet Nam chua cd hoac cd ma chua phat hien ve cac vu ngd dpc nao cua con

ngudi lien quan den m o i trudng trdm tich bien nhung tren the gidi da cd nhung bai hoc ddt gid vi su 6 nhidm nay. Dd xac dinh dupe chinh xdc mdc dp, pham v i anh hudng cua d nhidm k i m loai trong tram tich bien cua khu vuc ddi vdi he sinh thai ndi chung va ddi vdi con ngudi ndi rieng can phai co su ddu tu, nghien cuu chi tiet hon nua.

V i vay, can phai kiem soat 6 nhidm tai ngudn; nang cao nhan thdc cua ngudi dan trong cong tac bao ve moi trudng; phd bien, ban hdnh luat bao ve m o i trudng sau rpng trong cac tdng ldp nhdn dan thdng qua cac phuong tien bao chi, truyen thanh, truydn hinh..; ddng thdi phai cd nhung che tai x u phat that nghiem nhung ca so, cd nhan gay 6 nhidm vi pham luat bao ve moi trudng.

^ KY YgU "CAC Pg TAI NGHIEN CUU KHOA HOC- CONG NGHg NGANH TAI NGUYEN VA MOl TRUONG GIAI DOAN 2002-2006'

Vung nghien cuv tiem an cac tai bien:

X o i la duang ba tai cua Bang va doc song L a m ; hien nay doc theo hai bo song Lam, Nha nude da xay ke da nham bao ve bd. Dac biet x o i l a bd bien tai Bac cira H o i da anh huong den canh quan va chat luong bai tdm tai Cua L o . Can phai co nhung bien phdp chdng x d i l d dd bao ve bai tdm cua L d nhu xay ke, nuoi bd...

Qua trinh bdi tu lap ludng va bdi lap cang quan sat duoc tai cda H d i , cua Bang vd cang Nghi Son. Do lupng trdm tich tich tu tai cua song va cang bien da tao thdnh cac bar cat giua ludng, san lap cang va gay nguy hidm cho tau thuyen ra vao cua sdng, cang. Theo ket qua tinh todn tdc dp ldng dpng trdm tich tai cua H p i va cua Bang la kha ldn (~2cm/nam). Do vay, can nghien cdu nhung thay ddi vd thuy thach dpng luc theo miia va cd nhung bien phap cong trinh nham han che qua trinh lap ludng va bdi ldp cang tai day.

Ngoai ra, trong vung con cd cac tai bien khac nhu bao, l u lut, xam nhap man xay ra tai khu vuc song Lam, cda Bang vd khu vuc ven bien. Hien tupng nhidm man xay ra khi trieu cudng ket hop vdi sdng to, nude bien ngam vao cac tui nude ngdm va tran vao ddng rupng gay nen man hod. Ben canh dd, viec dao nude gieng khoan va lam mudi khong theo quy hoach cua ngudi dan lam cho nude man xam nhap vao cac tdng chda nude Q, va Q2. Hien nay nude gieng tai cua H p i , Xuan H p i , Hai Binh cd dp man chat (2-4"/m); hien tupng nhidm man con xay ra tai khu vuc trong de xung quanh cac dam nuoi thuy-hai san va lam mudi.

III. NHU CAU KINH TE - XA HOI, DIA CHi AP DUNG a. N h u cau k i n h te - xa h p i :

Kinh te, xa hpi ngay cang phat trien thi nhu cdu cua con ngudi cang cao dac biet la chat lupng cupc sdng sinh hoat hang ngay, moi trudng va sdc khoe cpng ddng. Tuy nhien, song song vdi viec dap dng nhu cdu sinh hoat cua con ngudi, viec thai ra m o i trudng cac chdt dpc hai la mpt he qua tat yeu. Do dd, viec bao ve va nang cao chat lupng moi trudng ddi hdi phai dupe thuc hien mpt each nghiem tuc va chat che. De lam dupe didu nay, viec phan tich va danh gia mdc dp P nhidm cua cac chat thai dpc hai la mpt trong nhung nhiem vu ddu tien cua cac nhd phan tich moi trudng. V d i pham v i nghien cdu cua de tai, viec tap trung phan tich danh gia mpt sd dpc td huu ca OCPs, PCBs va mpt sd k i m loai nang trong tram tich tai cdc cda song, cang bien khu vuc Bde Trung Bp mang tinh thuc te va kha thi cao. Day la nhung chat rat linh dpng, bdn vung trong moi trudng vd kha nang gay o nhidm la rat ldn. Hon nua, viec xac dinh va danh gia tdc dp bdi ldng tram tich cho phep cd kha nang quan ly dupe chung: nhu nao vet dudng ddn tau, du bao cac tai bien bdi x d i cac cua, cac cang tai khu vuc ddi ven bd. Ket qua cua dd tai nghien cdu nay phdn nao se cung cdp mpt vai co sd du lieu, giup ich tdi cac nha quan ly, cac nha x u l y m d i trudng dd giam thieu mdc dp o nhidm do nhung hop chat nay gay ra.

b. Y nghla thuc tidn:

- Danh gia tdc dp ldng dpng tram tich cac cda song, cang bien cd y nghla to ldn

trong viec nghien cdu tram tich va danh gid muc dp san lap l u d n g lach cua song, cang bien.

Phuc vu cho cong tac quan l y su dung hpp l y va bao ve tai nguyen moi trudng cua song ven bien.

- Nghien cdu td hop ddng hanh cac chi thi danh dau phdn t u va cdc nguyen t d gay 6 nhidm khac cho phep xac dinh mdc dp vd nguon gdc gay 6 nhidm de quan l y bao ve moi trudng, bao ve sdc khoe cpng ddng.

KY YEU 'CAC DE TAl NGHIEN CUD KHOA HOC- CONG NGHg NGANH TAl NGUYEN VA MOl TRUONG GIAI DOAN 2002-2006"

- Tang cudng he thong ca so dir lieu m o i truong.

Dia chi ap dung:

- Cac co quan nghien cuu trdm tich luan, dia chat bien.

- Cac co quan nghien cuu va bao ve m o i trucmg.

- Cac co quan quan ly.

MOT SO KIEN NGHj

- Cdn tiep tuc ddu t u nghien cuu chi tiet hon ve dia hoa m o i trudng, dia chat m o i trudng, dia chdt tai bien vung nghien cdu nhdm phuc vu chuong trinh quan l y tong hop ddi duyen hai cua Nha nude.

- Can tien hanh gui va phdn tich mdu vdi sd luong nhieu hon; ket hop phuong phap

chi thi danh dau phdn i d va cac phuong phdp phan tich khac (dong v i P b^{2 I H}, C s^{n 7}) trong vung nghien cuu de khang dinh tdc do ldng dong trdm tich tai nhung vung cda sdng va cang bien dupe chinh xac.

- Tiep tuc su dung phuang phdp chi thi danh dau phdn t u trong nghien cdu trdm tfch vung cda sdng vd cang bien nhu cua Van Uc, cda Day, cang Cai L d n de xac dinh tdc dp bdi ldng cung nhu ngudn gdc d nhidm giup cac nha quan l y cd nhung bien phap hoach dinh chien lupc quan ly kinh te ddi ven bd, han che 6 nhidm, bao ve m d i trucmg,

- Xdy dung tram quan trdc mdi trudng d mpt sd vung cda song va cang bien ldn (cda Bach Ddng, cda Van Uc, cua Day, cda H p i , cua Nhupng, cua K h a u . . . )