Đặc điểm, nguy cơ ô nhiễm và các giải pháp hạn chế nguy cơ ô nhiễm các hợp chất PCBs và OCPs tại vùng biển mỹ thạnh vĩnh hải (sóc trăng)

OCPs trong tram tieh vimg bien Sdc Trang, ehiing idi da sir dung cdc phuang phdp phdn tich sac ky khdi phd kfit hop vdi sac kV edng kfit dieti lir.. S6 luong hip chdt OCPs dugc phat hicn

D\C DIFM NGUV CO 6 NHIKM VA CAC CIAI PHAP ll.\N C H E NGUV CO O NHIKM CAC HOP CHAT PCBs VA OCPs TAI VUNG BIEN M\ T I I \ M I - \ I.Ml

HAI (SOC TRANG)

Phnm Thi Nga, Lc Van Diic, Nguyen Duy Du>en

Trung tdm Dja chdl va Khoang san bien

125 - Trung Kinh Trung I ina, Cdu Gidy Hd Ndi

Email' lidhmtbicnmgu'oigmail.com Tom tat :

Trong vdi thdp ky vira qua d nhiem cdc hop chdl hiru ca clo ben virng dd thu hut sir chil y cua nhieu nhd khoa boc triin thU giixi do chinh khu ndng tieh liiy sinh hgc munh, ddc linh cao ddi vdi con nguiri vd cdc lodi sinh vat ciing nhu tdc ilinig xdu d<}n mdi trudng vd cdc he sinh thdi

Do linh bi'n virng lucmg ddi cao cdc hop chul PCBs vd OCPs dd diroc lich liiy nhieu trong cdc mdi irire'rng khdc nhuu (trdm tich nude, sinh vdt )

vd phdn ldn deu cd ngudn ge'rc lir luc diu Vi vdy cite chirerng trinh nghien ciru ddnh gid su ldn luu vdn chuyen cdc herp chdl hiru ca clo trong mdi tnrdng Irdm tich lai ddi duyen hdi (Coastal Zone) du diroc thuc hien bcri cdc ca quan nghien ciru Irong vd ngoui nude

Ndi dung hdi bdo niiy trinh bdy due diem phdn bd cdc herp chdt PCBs Oi 'Ps

vd nguy CO d nhiem cdc herjy chdl nil)' trong trdm tich vitng bien Sdc Trdng tir do diru ra kien nghi vd gidi phdp phdng trdnh Ddy Id mat phdn ket qud ciiu DU

dn "Khao sdt, ddnh giu tiem ndng tdi nguven khodng sim viing bten ven bir tinh V)c Trdng tyle TWO 000':

CHAKACTERISTICS, Ti IE RISK OF POLLUTION AND MEASURES TO REDUCl Till-: RISK OF POLLUTION COMPOUNDS OI' PCBS AND OCPS IN WATER SEA IN

MY THANH - VINH HAI (SOC TRANG PROVINCE)

Pham Thi Njja, Lt Van Due, Nguyen Duy Duyen

Abstract:

During the last deeudes environmenlul pollution, which caused by stable orgunic compounds, bus been uttrucied by scientists in the world due to their high bio-accumulation and teixicily for human, wildlife species und adverse impacts on ecosystems

Owing to their high slabilily, PCBs and OCPs "compeninds have

and they u ere mostly originated from conlinenls Therefore, investigations und monitoring progrums have been implemented by scientific insliliiles world-wide in order lo evaluate the distribution and accumulation of these organic compounds in sediments of coasted ureas

'!his uriicle is uimed lo set forth distribution churacterislics of PCBs, (K Ps compounds in sediment of Soc Trang coastal urea, then to suggest reasonable retommendutions for the studied ai ea

I MO DAI Vimg bien Sde Trang ehiu dnh hudng iryc tiep lii he lh6ng sdng Ciru Long dd ra bicn qua cdc cua Dinh An, Trdn De My Thanh (hinh 1) Noi ddy cd ngudn ldi nguyen thien nhicn pliong phii \-di dien lich ldn rirng ngap man cdc bai Iricu ldy va ddl ngdp nude ihudng xu\en Dd Id nhung diC'u kifin thudn Igi eho \iec phdl irifin cdng bien, du Ijeh sinh ihdi \ d e d c ngdnh kinh le khdc nlur nudi Irdng ddnh bdi hai sdn du lieh

La khu \ u c cliiu dnh huang eua san xual ndng nghifip cao, sii dung nhieu hoa chdl bdo

\ c ihye \dt (ihuiic Irir sau dicl co ) eua \ung Ddng bang sdng Ciiu l.iMig ciing vdi cdc hoai ddng nhdn sinh khde irong khu vyc nhu' edng nghifip, khai ihac lai ngu}'cn dat ngap nude, khodng san giao ihdng \dn ldi, do xd cde chdl thai irong san xudl vd sinh hoai la nhirng ngudn phdt tdn cdc hap chdt OCPs, PCBs \do cdc he ihonu kenh rach %'d bifin ven

bo

Dc phuc \ u cde nine ticu \ a \ dung kinh le \ a hgi \iee nghifin ciru dia hda mdi Irudng dac biet la nghien eiiu mirc do d nhifim cdc hop dial hu'u eo d o (PCBs OCPs) Irong tram lich \iing bifin Sde Trang gdp phan ldm co sd kht>a hge eho phdt irien ben viing vd quy hoach sil dung hgp Iy ldi ngusfin

II PHI ONG PHAP PHAN TICH

De nghiC'n ciru mirc do d nhifim cae hgp ehdi PCBs OCPs trong tram tieh vimg bien Sdc Trang, ehiing idi da sir dung cdc phuang phdp phdn tich sac ky khdi phd kfit hop vdi sac kV edng kfit dieti lir Mdu tram tieh duge chiet 3 ldn vdi dung dich axeton va dich chicl

duge chuyen \ iio pheu chiel chua 100ml hexan \'d 600ml nude rira dd rii'a bang hcxan Sau

dd dich chiet dugc cd \'d cbo qua cot nhdi Florisil de lam sach va phdn lach C) giai doan dau lien p.p'-DDli \ a PCBs dugc rira gidi bdng hcxan giai doan Ihir hai rira giai bang hdn ligii 20% dielomclan trong hcxan \'d ihu duge p.p'-DDD, p,p"-DDT vd cdc ddng phdn

\IC\1 Luu huynh dugc loai bang dong boat hda San pham ciia mdi giai doan duge ed rdi

bom len may sae ky khi \'di deleelor cdng ket diC'n Hi (GC-ECD) dfi dinh lugng Gidi ban phdl hicn ciia cdc hgp chat lri;n dao dgng tir 0,001-0,0 Ing/g [2,3,4]

Cdc chi lieu phdn lieh tren dugc lien hdnh tai I'lidng Phan lich Trgng difim Qudc gia thugc Vicn 1 Ida hgc Cdng ngbicp

111 DAC DIEM VA NGUY C O 6 NHIEM CAC HOP CHAT HlTU CO (I'CliS,

OCI'S) TAI VUNG BIEN SOC TIJANG

1 Dac dii;ni phiin bf> cac hop chat PCUs va OCPs trong tram tich tang mat [1 ]

Ham lucmg t6ng PCUs va OCPs dao dong trong lihoang kha rgng, PCBs: 2,98-8.50ng/g

va OCPs: 0,20-0,j0ng/g (bang 1.2) S6 luong h(ip chdt OCPs dugc phat hicn chii yeu tir 3-7 hgp chit: lihu vuc cira" My Thanh (3-7 hgp chat), cira song xa VTnli Hai (4-5 hgp chat), Trong khi do, s6 luang hop chit PCBs tai khu vuc cira My Thanh va ciia song xa VTnh llai ciing la 15-16 hop chat

a) Dac di(;m phan bo cac hop chat Ihu6c trir sau goc clo (OCPs)

Sfl lugng cac hgp chSt OCPs co mat trong trong mau tram tich tang mat kha da dang, voi su CO mat cua'cac hgp chat: a-HClI, y-lICll p-llCH, 6-llCll, p,p DDE, p.p'-DDD p,p'-DDT (bang 1) Trong do hgp chat p.p'-DDE co ham lugng chicm uu the (p.p'-DDli 0.15-0.20ng/g);''cac hop chat con lai (a-llCll, y-lICII, [J-llCH, 6-UClI p, DDD, p,

p'-DD T) CO ham lugng nho va dao dgng trong khoang ND-0,04ng/g (bang 1)

Hinl, 1' So do vi ti'i cliein mdu chi Ihi ddnh ddu phdn lu vung hien Scjc Trdng Bdng J: Tham so dia hoa mui Irudng cdc hap chdl OCPs

(Don vi hdm hrang ng/g N=22 mdu)

(•|1M\

('lillll

Clh

u - l K I l

11.01

ND

0,01

y-lKII

O.lil

ND 0.0!

P-llCI!

O.OI 0,01 0,01

6 - I K I I

0,01 0,01 0,01

p,p'-»ni:

0,20 0.15 0.18

p-p'-DDD

0,01

ND

0.01

p.p'-ni) r

0,04 0,03 0.03

-fim o< !•''

0,30 0.20 0,26

b) Diie difim phan bo cac hop chSt PCBs

Trong Iram tich ldng mat viing bien Sdc Trang thanh phan ciia PCBs gdm ddng dang eiia nhdm il clo den nhifiu clo: 2,4,4' triclorobipbenyl; 2,2',5,5'-leiraclorobipheiiyl; 2.2'.4.5.5'penlaelorobipbenyl; 2,3,4.4\5 Pentacblorobipbcnyl; 2,2',3,4,5,6'-Hexachlorobiphcnyl; 2,2\3.4,4',5 hcxaclorobipbenyl; 2,2',3,4,4',5,5' heptadorobiphcnyl

vd ldng 2Cl ldng 3C1, ldng 4C1, tdng 5C1, tdng 6C1, ldng 7C1, long 8CI, ldng 9CI, tdng lOCI Ham lugng tdng PCHs dao ddng trong khoang 6,56-8.5ng/g, dat gid tri trung binh 7,47ng/g Trong dd, eac hgp chdt chifim chii yfiu trong man: 2,2',3,4,5,6'-Hexachlorobiphenyl; 2.2\3.4.4'.5 hexaelorobiphenyl; 2.2",3.4,4\5,5\ tdng 6CI (bang 2)

Bang 2: Thum sd dia hiru mdi truimg cua cdc herp chdl PCBs

(Dan VI hum luerng ng/g: N=22 mdu)

Hop dial Tliam so " _^_^

2,4.4 iriclorobiphcny]

2.2 ,5,5 -Ictraclorobiplicnyl

2.2.4.5.5 pcnlacJorobipliL'iivl

2,3,4.4 5 Pcnlaclilorobiphcnvl

2,2",3,4,4",5,5' lieplaclorobipiicnyl

T6ni! 2CI

T6im 3CI

Tons 4CI

Tona SCI

Tiini" 6C1

Tom: 7CI

Tina SCI

Tina 9CI

Tfina lOCI

Tina PCB

Cmax

0.54 0,38 0.03 0.02 2,00 4.30 0.16 0.04 0,54 0,45 0,16 7,55 1,30 0,29 0,13 0,01 8,50

Cmin

0,20 0,03

ND 0,02 1,59 2,41 0,05 0,01 0.20 0,07 0,01 4,73 0.27 0,01 0,02

ND 6,56

Ctb

0.37 0,20 0,01 0,02 1,82 3.15 0,10 0,02 0,37 0,25 0,09 5,93 0,62 0.11 0,06 0,00 7,47

ND nhd hern giai hgn phdl hien ciia thicd bi phdn lich

c) Dye diem phan bo cac hop chat PCBs va OCPs theo chieu sau cgt miiu

Trong vimg bien Sde Trang, da lien hdnh thu thdp va phan tieh cae mau trong ept mau lay lai cira My Thanh vd cira sdng xd VTnh Hai Ket qua cho thay cac hgp chat OCPs va PCBs cd ham lugng ldng dao dgng trong khodng 2,98-8,50ng/g vd 0,02-0,54ng/g luang

mg (bdng 3, 4)

Bdng 3 Tham s6 dia Iwu mdi trirdng eiiu cdc hap chdl OCPs trong cdc cgt mdu

(Dem vi hum luong- ng'g A'=^22 mdu)

k l i u

Cira

M \

lh.iiili

Cua

stiny

Vitili

llai

CVI mflu

n i ) S - l l 2 3

(ll-153Lml

1108-1125

1108-1312

( U - l l 2 c m )

.S5

10 mau

8 111.U1

-1 m.^ii

I h a m

f m j \

Cmin

Clb

Cin.i\

f m i i i

(.111

C m i \

Cmin

t l b

[i-n( I I 0.01

N l )

0 0112

0 0 f

N i ) 0.1)1

M )

N l )

N l )

r - i i c i i

0 03

N D

0 01 0,02

N l ) 0.01

N l )

0 003

p - I K I l

1104

N l )

0 02 0.01

0 02

N l ) 0,01

&-IH IE 0,1)2

N l ) 0.(11 0.1)1 O.OI O.OI O.OI

p, p-oDi:

0.38 0.01 0.37 N!) 0.21 0.16 0.02 0.11

i) n'-i]i)i)

().()! N H

O.OI 0.0; 1

M ) 0.01

N I ) 0.004

p li'-DDI 0.05 0.01 0.03 0.02 0.02 0.U4 O.OI 0.02

ND nho hern gidi hgn phdl hii

Bung -I Tham sd dia

77 cua duet bl phdn tich hda mdi irudng cdc hap chdl PCBs trong cdc col muu (Dem vi hiim luong ngg, N=22 muu)

So hioo cot mail

K h u MIC

C h i c u sau cot m.iu

So Iirona man

T h a m so 1 l a p chat

2.4.4 t r i c l ( ] r o b i p b c n v l

2,2 ,5,5 - t c t r a c l o r t ) b i p h c n v l

2.2 4.5.5 p c n t a c l o r o b i p h c i n 1

2.3.4,4 ,5 P e n t a c h l o i o b i p h c n \ 1

• ' ^ ' 3 , 4 , 5 6 ' - H c \ a c l i l o r o b i p l i c n \ l

2.^ ,3.4,4 ,5 h c \ a c i u r o b i p l i c n \ 1

T o n a 2CI

T 6 i i g 3 t 1

Toil.a SCI

T 6 n a 6CI

T 6 i i g 7 C I

T o n a SCI

r d n a 9 t 1

T o n g lOCl

l o n g I'C 15

U 0 8 - 1 I 2 3 Ctia M i

0 - 1 5 3 c m

10 mau

C m a x 0,77 0,44 0.11 0,03 2,34 2,41 0,26 0,09 0.47 0.49 4.73 0,13 0,13 7,34

C m i n 0,14 0,10

N D 0,01 0.41 0.08 0.01 0,14 0,12 0.03 1.96 0,13 0,01 0,01

N D 2,98

Ctb 0.52 0.04 0,01 1.07 1.66 0.13 0,03 0,37 0,15 3,54 0,31 0,04 0.06 0,003 4,92

llOS-1125

1 lianh

0 - 8 0 c m

8 mau

C m a x 0.58 1.01 0,04 2,07 4,30 0,26 0.11 0.58 1.55 0.78 7,55 0.34 0.33 0,03 8.50

C m i n 0.21 0,04

N D 0,01 1,05 1,26 0,07 0,01 0,21 0,09 0,01 0,09 0,03 0,01

N D 4,12

C t b

0 , 4 0 0.01 0,02 1,48 2,05 0,16 0,41

0 , 4 6

0 1 9 0,26 0,17 0,04 0,01

1308-13 12

C u a song v,i V i n h 1 I n

0 - 1 1 2 c m

C m a x 0.59 0,32 0,04 0,02 2.75 0.20 0.59 1 0.36 0,29 5.51 0.29

0 " i 0,01 6,56

4 m a n

C m i n 0,20 0,03

N D 0.01 0,71 0,84 0,05 0.04 0,20 0,07 0,11 2,11 0,05 0.04

N D 3.86

C l b 0.56 0,14 0,02 1 0.02 1.37 1.61

0 11 0.07

T r 3 6 0.16 3,54 0,24 0,19 0.0112 4.82

ND iilio liuii gidi han plidl h,S,i cia IhiSl bi phdi, lich

Trong col mau B08-1I23 (0-153ciTt) lay tai khu vuc ciia My Thanh, ham lugng long OCPs CO gia Iri 0,29ng/g trong tram tich tang mat (0-lOcm), giam xu6ng gia tri cue lieu tr

do sau IO-20cni (0,09ng/g) sau do tang cao ttii giii iri cue dai: 0,47ng/g li do sau tti X''-92cm va giam xuong ti cac do sau tiep Ihco (I09-I53cm): 0,21ng/g Trong khi do, ham

ddn Ihco do sau cdt mdu vd dat gia tri cue ticu d d d sdu (125-140em): 3,51ng/g(hinh 2)

Ifmh 2' Dd thi hien thien hum Immg hap chdl OCPs vd PCBs ciia col mdu B08-I123 ldy

fgi khu vuc ciru My Thgnh

Trong col mdu B08-1125 (0-80cm) ldy d khu virc cira My Thanh, ham luong tfing OCl*.s cd gid iri 0.27ng/g irong tram tich tang mat (0-lOeni), sau dd gidm ngay xudng cue lieu' 0,04ng/g d do sau 10-20cm, ihco chieu sdu cgt mdu (20-50cni) OCPs cd ham lugng lang ddn: 0,34ng/g-0,40ng/g, sau dd gidm xuong d do sdu 50-70cni vd dat gia tri cue dai d

dg sdu 70-80cm: 0.44ng/g Tuy nhien, PCBs cd ham lugng tdng dat gia trj cue dai trong tidm li'cli tang mat (0-IOcni): 8,50ng/g, dat gia tri cue lieu d dd sdu Idn nhat (70-80cm): 4,12ng/g(liinh3)

////;/) 3 Di) ihi bien thien hdm luang hgp chdt OCPs vd PCBs ciia cot mdu B08-1125 lay

lui khu vuc ciea My Thanh

DOCPs

n PCBs

50-72 90 112

u tilt mUa ((.ml

Hinh 4- Dd thi bien thien hdm lugng hgjr chdt OCPs vd PCBs ciia col mdu BOS- 1312 lay

Ddi vdi cdt mau thu dugc tai khu vuc cua sdng xa VTnh Hdi B08-1312(0-112em) hdm lugng tdng OCPs ed gia tri 0,21 ng/g d do sau 0-20em, gidm xudng tdi gia tri cue lidu d dd sau 50-72em (0,05ng/g) sau dd tang cao dat gid in cue dai d do sau 90-112cni (0,22ng/g) Trong khi dd ham lugng tdng PCBs dat gia tri cue dai (6,56ng/g) trong trdm tich tdng mai

d dd sdu 0-20cm, sau dd gidm dan theo chicu sau edt mdu va dat gia tri cue tieu d do sdn 90-112em (3,86ng/g)(hinh4)

Qua dae diem phdn bd cdc hgp chdt PCBs va OCPs theo khdng gian vd thdi gian cd Ux" dua ra nhan dinh rang cac hoat ddng lau ihuyen va edng nghiep trong \'iing dang dicn i:i manh me trong khu vuc ddn den viec tang cao hdm lugng tdng PCBs trong ldp Irdm licli tang mat Trong khi dd viec sir dung cae hgp chat OCPs ed ngudn gdc tir cdc hgp ch.u thudc bao vc Ihuc vat da dicn ra manh mc tir cae Ihdp ky trude, sau dd gidm dan va hieu dang cd xu hudng tang len

2 Du bao nguy co" o nhiem moi tru'ong trong tram tich bd'i cac hop chat PCIis s y

OCPs II]

Do Viet Nam ehua ed tieu chuan mdi trudng de ddnh gia chdt luong mdi trudng lidm lieh bien, ehinh vi vdy de danh gia ehat lugng nidi trudng tram lieh cua khu vuc nghien

cii'u chiing ldi da so sdnh hdm luong ciia mdt sd bgp chdt huu eo clo vdi ticu chudn \\\\ \

trudng tram tich eiia Canada (bang 5)

Trong cac mau tram tich lay lai vimg bien Sdc Trang, tdng ham lugng PCBs dao dgng trong khoang 2,98-8,50ng/g thap hon so vdi mirc hicu ung ed ngudng-TEL (21,5ng/g) \d Ihap hon rai nhieu so vdi mirc hieu img cd ihe-PEL (189ng/g), vdi he sd d nhiem To: 0,13-0,39 (bang 5) cho thay tram lich trong vimg chua bi d nhiem bdi hgp chat PCBs Cae hgp chat thude Irir sau, diet ed (p,p'-DDD, p,p'-DDE, p,p'-DDT va lindane) ed he so d nhiSm trong khodng 0,008-0,18 (bdng 5), nhu vay tram tieh viing nghien cuu chua cd bicn hien d nhiem bdi cdc hgp chdt nay

Bdng 5- Hdm hrgng ciia mdt sd hap chdt thudc bdo ve thuc vdt vu PCBs trong trdm lich lay tai viing bien Sdc Trang so vdi Tieu ehuan mdi trudng trdm tfch bicn cua Canada

(Dan vi hdm lugng- ng/g: N=22 mini)

Hop chiit

p,p'-DDD

p,p'-DDE

p,p'-DDT

Lindaii (a - HCH)

T6ng PCBs

Ham lirong (ng/g) 0,01 0,38 0,01-0,05 0,01 2,98-8,50

TEL (ng/g) 1,12 2,07 1,19 0,32 21,5

PEL (ng/g) 7,81

374 4,77 0,99

189

lie so 0 nliicm (To) 0,008 0,18 0,008-0,04 0,031 0,13-0,39

Mac dil vimg nghien ciru khdng hi d nhiem cac hgp chat PCBs va cac hgp ehat thudc trir sdu diet cd, nhung n6u cu tiep tuc gia tang cdc hgat dgng cdng - ndng - ngu nghiep tai khu vire nay thi nguy ca d nhi^m cac hgp chat tren la khdng tranh khdi

IV CAC G U I PHAP HAN CIIE NGUY CO 6 NHIEM DO CAC HOP C H A T PCBs

VA OCPs

Nhu chung ta da biet, vimg bien Sdc Trang cd mat hdu het cae hgp phan huu co cua thudc trir sdu gde clo, vdi nhirng mirc ham lugng khac nhau phan bd d nhirng do sau khac nhau Qua ket qua Iren eho thay ham luong thudc trir sdu gdc clo va PCBs dugc sir dung theo tirng thdi ky khdc nhau Trong viing cd mgt sd khu cdng nghiep, nha may hda chat, cac boat dgng san xuat ndng nghiep, boat ddng danh bat thiiy hdi sdn dien ra manh me, giao thdng van tai dudng thiiy phat trien Tuy hdm lugng eac hgp ehat PCBs va OCPs chua vugt qua cdc muc gidi ban cho phep theo lieu chudn d nhiem mdi trudng tram lich cua Canada, nhung vice lang cao ham lugng OCPs va cue dai ham lugng PCBs trong ldp tram tich tdng mat cua cae cgt mdu la dang luu y Do dd, mdt sd giai phap cdn dua ra nhdm kiem soat su phdl tan ciia cdc hgp chdt nay vdo cac hgp phan mdi trudng cu the la:

1 Trong sdn xual cdng nghiep: cdn sir dung cdng nghe cao it phe lieu Khi xdy cdc cdng trinh mdi can ed bien phap xir ly nude ihdi, khi thai ddm bao miie do sach tieu chuan hien dai Irudc khi dugc thai ra mdi trudng Can thu gom va xir ly nude thdi va ehat thai r5n

- Trong san xuat ndng nghiep: su dung dung cac Ioai thudc tang trudng, thudc bao ve thirc vat dugc Nha nude cho phep, sir dung dung lieu lugng eac ehat bao ve thuc vat, tang cudng sir dung phan bdn huTi co

- Ddi vdi chat thai sinh boat: can tuyen truyen van ddng nhan dan ed y thirc bdo ve mdi trudng IChdng xa rae thai true tiep xudng sdng, bien Thuc hien tdt xu ly rac thai trong cac benh vien

- Can cd su phdi hgp giira cac co quan hanh chi'nh, quan ly cap trung uong, dia phuong, cac nha khoa hgc va dan dja phuang nham:

2 Tang cudng hgp tac trong cdng tac nghien cim va bao ve mdi trudng trong khu vue

3 Thue hien danh gia tac dpng mdi trudng va cac giai phap giam thieu cac chat d nhiem ngudn gdc nhan sinh cho tat ca cac du an trong khu vuc

4 Thi6t lap he thdng quan tr^c nhSm kiem soat chat lugng mdi trudng dgc theo sdng, cang bicn va ven bien dc ed the canh bdo va ehuan bi hd so khuyen cao cdc cap cd tham quyen can thiep khi cd bieu hien d nhiem hay cd su cd mdi trudng

5 Nghiem cam viec thai nude thai, chat thai cdng nghiep va sinh boat xudng sdng, xudng bicn khi chua qua xir ly

6 Nghiem cam eac tau, thuyen het ban sir dung hoat dgng trong khu vue

7 Giam thieu cdc cay xang di ddng tren bien va cac hinh thirc budn ban xang dau qui

IV KET LUAN

1 Trong tram ti'ch tdng mat, ham lugng tdng PCBs va OCPs dao ddng trong khoang kha rgng, PCBs: 2,98-8,50ng/g va OCPs: 0,20-0,3Ong/g Sd lugng hgp chdt OCPs duge

phat hien ehii y6u tir 3-7 hgp chdt, trong do hgp chat p,p'-DDE cd ham lugng chiem uu

lbs Sd lugng hgp chdt PCBs tai khu vuc eira My Thanh va cua sdng xa VTnh Hai eimg !d 15-16 hgp chdt, trong dd cac hgp ehat chiem chii yeu trong mau: 2,2',3,4,5,6' Hexachlorobiphenyl; 2,2',3,4,4',5 hexaelorobiphenyl; 2,2',3,4,4',5,5' va tdng 6C1

2 Trong eac cdt mau tram tieh hop chat OCPs va PCBs cd ham lugng tdng dao ddng trong khodng 2,98-8,50ng/g va 0,02-(),54ng/g Ham lugng PCBs ca 3 cgt (1123,

B08-1125, B08-13I2) mdu dSu cd xu hudng gidm ddn theo do sau Cdn ham lugng PCBs cd su bien ddi d cac do sdu khdc nhau

3 So vdi tieu chuan d nhiem mdi trudng ciia Canada thi tram tich vimg nghien ciiu chua cd bieu hien d nhiem bdi PCBs va cac hgp chat thudc bao ve thuc vat

4 Trong vimg nghien ciru cac yeu Id chi phdi dae diem phan bd ham lugng cac hgp chat eo clo ben virng trong tram tich la che do thuy-thaeh dgng luc cua he thong sdng-bien

vd eac hoat dgng nhan sinh dien ra manh me nhu danh bat nudi trdng thuy san, cong-ndng nghiep, che bien hai san va cac hoat ddng giao thdng thuy Day cung chi'nh la ngudn phdl tdn cdc hop chat hiiu ca ben virng cd ngudn goe nhan sinh vao cac he thdng thuy van va bien ven bd ciia viing nghien eiru Do vay can tang cudng cac bien phap quan ly va gidm thieu gia tang cac hgp chdt tren

TAI LIEU T H A M K H A O

Vu Trudng San (chii bien), 2007 "Khao sat, danh gia tiem nang tdi nguyen khodng sdn viing bien ven bd tinh Sdc Trang, ti le 1:100.000" Luu tru: DC, Ha Ndi

Charles R P et al, 1991 Interpretations of contaminant sources lo San Pedro Shelf sediments using molecular markers and principal component analysis Molecular Markers in Environmental Geochemistry, Washington

Iwata, H ct al, 1994 Geographical distribution of persistent organoehlorincs in air, water and sediments from Asia and Oceania, and their implications for global redistribution from lower latitudes Environmental Pollution 85, 15-20

Viet, P H et al, 2000 Persistent organoehlorine pesticides and polyehlorinalcd biphenyl in some agricultural and industrial areas in Nolhern Vietnam Water SciciKc and Technology Vol 42 No 7-8 , p 223-229