NGHIEN CU'U PHAN TICH VA DANH GIA DU" LU'CNG MOT S6

TAP CHI HOA HOC T. 51(1)22-27 THANG 2 N A M 2013

NGHIEN CU'U PHAN TICH VA DANH GIA DU" LU'CNG MOT S6

CHAT 6 NHi^ivi Hi/u c a T 6 N LU'U & VUNG CCPA S O N G CON, QU^ SON, QUANG NAM

Tran Thi Van Thi*, Lc Tlii My Hanh, Lc Trung Hieu Khoa Hod hgc. trudng Dai hgc Khoa hpc Hue

Dfin Toa soan 24-5-2012

Abstract

The concentrations of organochlorine pesticides and PCBs were determined in surface sediments, river water collected from the Con river and its estuary. Soil samples were also collected at the storage area and surrounding areas were analysed lo determine the residual levels of persistent organochlorine compounds. Results obtained show that the concentration of organochlorine pesticides (OCPs) in sediments for DDTs ranged from 3 8 to 6.8 ng/g; for cyclodienes fi-om 5.0 to 10.1 ng/g, for PCBs from 14.2 to 104.8 ng/g. The concentrations of the DDTs, PCBs, cyclodienes and HCHs in soil samples ranged from 3 6 to 1351.3; 3.9 to 7114 2; 2 5 to 1377.3 and 20.9 ng/g, respectively.

Keywords: Organochlorine pesticide residues, PCBs, simultaneous analysis, gas chromatography.

1. GIOI THIEU

Cac chat 0 nhiem hUu co khd phan hiiy (POPs)- bao gdm cac thudc trir sau ca d o (OCPs) sir dun;

trong ndng nghiep va cac hgp chat PCB (PCBs) sir dyng trong cdng nghiep - cd anh hudng ldn ddi vdi sue khde ciia con ngudi, da dang sinh hgc va mdi trudng sdng [1, 10]. Sau khi dugc sir dung, cac hgp chat nay van tiep luc tdn luu trong qua hang chuc nam va gay anh hudng lieu cue ddi vdi mdi trudng.

Nhieu cong trinh nghien ciru da tien hanh phan lich ddng thdi cac thudc trir sau ca cio va cac PCB trong cac nen mau khac nhau nhu nudc, dat, tram tich, sinh vat [6]. Viec phan lich ddng thdi cac hgp chat nay vira don gian hda dugc quy trinh phan tich, vira liet kiem dugc thdi gian, chi phi so vdi phan tich tirng loai hgp chat rieng biet [1].

Tren dia ban huyen Que San, tinh Quang Nam hien nay cdn tdn tai tngt kho thudc bao ve thuc vat cd kha nang phat tan cac hgp chat ca cio. Tren dia ban huyen cdn cd khu cdng nghiep Ddng Que San cd dien tich 600 ha, cum cdng nghiep Que Cudng cd dien tich 40 ha, cum cdng nghiep thj Iran Ddng Phii cd dien tich 50 ha. Toan huyen cd khoang 631 ca sd san xuat cdng nghiep va tieu thu cdng nghiep nhung viec xir ly nudc thai chua dugc quan tam dung muc, nudc thai chua qua xu ly da thai true tiep ra moi trudng [2]. Cho tdi nay, chua cd cdng trinh nao nghien ciru ve van de nay. Vi vay, viec phan tich va danh gia du lugng cac chk 6 nhilm hiru ca ton luu d

viing cira sdng Con, Que Son, Quang Nam la cap thiet de cap nhat thdng tin ve mdi trudng.

g 2. THU'C NGHIEM 2.1. Lay mau va chuan bj mau

Mau dugc lay vao miia xuan ngay 12 thang 2 nam 2012. Tdng sd mau ISy bao gdm 5 mau nudc, 5 mau tram tich va 6 mau dat. Trong dd, mlu nudc va mau tram tich dugc ISy tai ciing tga dg. Mlu d5t tai kho tdn trii' la mau Id hgp dugc lay tir 5 vj tri trong kho, cac mau dat khac la cac mau don lay tai cac vi tri da xac djnh. Vj tri lay mlu dugc th6 hien d hinh 1.

2.2. Hoa chat

Chuin PCBs gom 6 ddng lo^i (PCB 28, 52,101, 138, 153, 180); chuan dan le ciia 9 thuoc trir sau co cio bao gdm: p.p'-DDE, p,p'-DDD, p,p'-DDT, a- HCH, y-HCH, S-HCH, Dieldrin, Endrin, Heptachbr;

chat ddng hanh trich lorobenzen; chat ngi chuan pentachloronitrobenzen. Hda chat tinh khi8t (Merck):

axeton; etyl axetat; mudi khan Na2S04 (nung d 450°C trong 4 gid) va NaCI (ho^t hda d 250''C trong 4 gid), Florisil (hoat hda d I80°C trong 12 gid, roi bao quan trong binh hut km), H2SO4, n-hexan (Han Qude): cat phan doan vdi cgt dai 0,8 m, thu d 68°C. K£t qua phan tich GC/ECD cua «-hexan sau khi da chung cat cho dudng n8n on dinh.

TCHH, T. 51(1), 2013 2.3. Chiet va Iam sach mau 2.3.1. Chiit mdu [1]

Mlu nudc sau khi Igc dugc tien hanh chiet Idng- Idng bang dung mdi «-hexan. Mlu nudc (Hit) dugc n-hexan, mdi Ian chiet vdi ti I? thi tich nudc: n- hexan la 10:1 (v/v). Sau dd lam khan dung mdi chiet bang each cho qua phSu Igc cd chua Na2S04 khan.

Mlu dat (trim tich) dugc dem chiet bing h?

thong soxhlet. Them 100 ng/mL chit dong hanh vao 10 g mau, chiet bing hdn hgp /i-hexan/etyl axetat (3/2, v/v) 120 mL, trong thdi gian 12 gid.

2.3.2. Lam sgch vd Idm giau mdu

Mau chiet dugc lam giau ve 2-5 mL tren thiet bi cd quay. Dich chiet cd d^c dugc xir ly bang H2SO4 dgm dac va tiep tyc rira bing nudc cat den khi khdng cdn axit nita. Sau dd xir ly bing phoi ddng da dugc ho^t hda de lo^i cac hgp chat luu huynh.

Cot chiet pha ran florisil (1 g) dugc su dyng de lam sach dich chiet. Sau khi chuan b] xong cot florisil, toan bg dich chiet dugc chuySn len cgt, rira giai cdt vdi 70 mL hdn hgp H-hexan/axeton 2%, toe dg rua giai 4-5 mL/phiit. Djch rua giai dugc cat quay giam ap d 40-5D°C ve the tich 1-2 mL va sau dd dugc chuyen vao dng thuy tinh 10 mL vdi mgt lugng nhd hexan. Djch tiep tuc dugc cd dudi dung mdi bang ddng khi nita, them chat ndi chuan pentachloronitrobenzen (PCNB) va dinh muc dSn the tich I mL de phan tich bang he thdng sac ky GC- ECD [2].

2.4. Quy trinh phan tich

Vi?c phan tich ham lugng OCPs va PCBs dugc thyc hi?n tren thiet bi phan tich GC-ECD (Agilent 7890A) t&i Trung tam Ky thuat Tieu chuIn Do ludng Chat lugng II - Thanh phd Da Ning (mgt sd mau dugc th\rc hi^n tren thiet bi GC-MS). Cgt mao quan DB-5MS (30mx0,32 mmx0,25 ^m) vdi tdc dg ddng khi N2 la 12 psi (2,0904 mL/min). Nhiet do injector va detector lan lugt la 270°C, 300°C.

Chuang trinh nhiet dg GC tang tir 120^0 den 170°C vdi tdc dg nang nhiet 4°C/phiit va thdi gian giu 15 phut; sau dd !en tdi 180°C vdi toe do l°C/phiit, thdi gian gift 2 phut; cudi ciing len 240*'C, tdc dg °C/phut, nhiet do dugc giu' trong 5 phut. He thong GC hoat dgng theo ch8 dg chia ddng (5:1), 2 ^L mlu duge tiem vao he thdng GC 6h phan tich dinh lugng tdng OCP va tdng PCB. PCNB dugc sir dung lam chit ngi chuan [4, 5].

Phan tich djnh Iugng tong OCP va tdng PCB sir dung phuang phap ngi chuan. Dudng chuan ciia cac

Tran Th} Van Thi vd cgng sic chat chuan dugc xay dyng vdi h? sd tuang quan Idn (R > 0,997) Ham lugng tong PCB se dugc tinh bing tong cua 6 PCB dong loai nhan vdi he sd 4,81 - gia trj tuang duang quy cho hdn hgp Arochlor 1254 [I].

Gidi ban phan tich dinh lugng cua phuang phap (MDL) vdi tong OCP tir 5,72 den 21,02 Mg/L ddi vdi mau nudc; vdi tong PCB tir 9,56 din 44,62 ^ig/L ddi vdi mau nudc.

3. KET QUA v A T H A O LUAN

3.1. Ket qua phan tich OCP va PCB trong cac mau moi trudng

Vdi quy trinh phan tich da chgn, chiing tdi tiln hanh phan tich OCP, PCB trong mau nudc, trim tich va dat tai huy?n Que San. Ket qua phan tich du lugng OCP va PCB trong cac mlu dugc the hien d bang 1. Doi vdi mau nudc: Nl, N2, N4, N5 (phan tich bang GC-MS) deu khdng phat hien dugc, rieng mau N3 (phan tich bang GC-ECD) cd ham lugng heptachlor (47,11 ng/L) chua vugt muc cho phep theo QCVN 08:2008 cua Bg Tai nguyen va Mdi trudng la 0,05 |,ig/L. Ndng dp cac chat can phan tich trong mau dat tai kho tdn trir cd du lugng hgp chat ca c\o rat ldn trong ca 2 kit qua GC-ECD va GC- MS, vugt muc gidi han cho phep theo QCVN 04:2008 cua Bg Tai nguyen va Mdi trudng la 0,01 mg/kg. Ham lugng DDT, PCB len din hang tram, hang ngan ng/g, dIu la ngudn phat thai cac hgp chit CO cto va PCB nghiem trgng ra cac khu vyc xung quanh.

Mau dat tai cac viing ian can kho tdn tri~r cd ham lugng chit d nhilm khdng Idn nhu tai kho tin trij.

Diiu nay cho thly, su phat thai Iheo con dudng tham thau va lan truyen trong dat rat cham chap (thudng la do dac diem ciia loai dat tai vimg khao sat), trong khi gan kho tdn trir lai ngui thay miii hda chat, Vdi dieu kien khi h^u ndng nhu d Quang Nam, cd the viec phat thai cac chat hiru ca de bay hai theo con dudng khuech tan trong khdng khi lai thay rd hon sir phat thai do cudn trdi hay tham thau qua dat.

Cac mau tram tich deu phat hien cac chat nhung vdi ham lugng ihlp. Chung tdi nhan thay tram lich d day chii yeu la cat sdi nen khdng cd kha nang luu giir cac chat ca cio phat tan tir kho tdn tru.

Nhin chung, ham lugng cac hgp chat nghien ciiu trong mau dat giam dan theo thii tu tdng PCB (77,50%) > tdng DDT (20,41%) > tdng cyclodiene (1,86%) > tdng HCH (0,23%). Theo nhilu tac gia, do ap suat hai cua HCH cao ban DDT nen tdc do bay hoi nhanh hon DDT, phan hiiy nhanh ban trong dat dudi tac dyng cua enzym, dan den du lugng cua HCH trong dat thudng thap hon DDT mac dii HCH dugc sir dung lam thudc trir sau nhieu han DDT [7].

TCHH, T.51(I), 2013 Nghien ciru phdn tich va danh gid...

Bdng I Nong dp cac chat phan tich trong cac mlu dat va tram tich

H<?p chat

Gamma - HCH Alpha-HCH Delta-HCH Heptachlor

Endrin Dieldrin DDI- ODD DDT PCB 180

PCB 28 PCB 52 PCB 101 PCB138 PCB153

Nong dg trong mlu, ng/L Nl

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Ghph' Gidi han phat hien; <gh (nho hon gldi han phat hi§n) -. khong thyc hien ph^p do.

Ham lugng cac chat trong mau tram tich giam din theo thu ty long PCB (87,22%) > tdng cyclodiene (7,90%) > tdng DDT (4,88%) trong khi cac hgp chat HCH lai khdng dugc tim thay trong cac mau tram tich. Viing cua sdng Con chinh la nai tiep nhan chat d nhiem tir cac hoat ddng cdng nghiep va dich vu dang dd vc, cd the vi the ma ham lugng PCB chiem ty le Idn. Ham lugng tdng HCH tai kho tdn tru va cac viing dat ian can ciia thj Iran Ddng Phii, huyen Que San co ham lugng tuang ddi thap (20.9 ng/g) so vdi cac kho ldn trir lai Thira Thien Hue (xa Quang Thanh, huyen Quang Dien la 782 ng/g; xa Phong Binh, huyen Phong Dien la 495 ng/g) [1].

Chinh vi vay ma trong cac mau tram tich deu khdng phat hien thay du lugng HCH, kha nang phat tan theo con dudng tham thau trong dat la thap.

Ham lugng tdng DDT lai kho tdn tru ham tugng rat cao (1860,3 ng/g) so vdi cac viing dat ian can (Di la 7,0 ng/g; D2.2 la 2,5 ng/g; D3.I la 3,2 ng/g, D3.2 la 9,5 ng/g) va trong cac mau tram tich (tdng DDT la 20,8 ng/g). Nhu vay, qua trinh khuech tan tir diem ndng ra mdi trudng xung quanh rat chain, hoac cd the trudc day nai nay la diem tdn trii' an loan, ed kho kin va bao quan dung each, tuy nhien DDT van

dang xam nhap cham vao mdi trudng xung quanh kho tdn tr&.

Cac ket qua ma chiing tdi nhan dugc cdn cho thay ham lugng DDE la chii yeu (ty le p.p'- DDE/tdng DDT cao han cac dan xuat cdn lai), hau nhu khdng phat hien dugc DDD trong cac mau tram tich. Nhu vay, da sd vi tri lay mau cd dieu kien ihu^n lgi cho sy phan hiiy DDT nhd vi khuan hieu khi Ihanh DDE - la ddng phan cd tinh ddc cao nhat trong cac ddng phan ciia DDT.

Ham lugng nhdm cyclodien tai kho tdn tru kha cao (159.8 ng/g) so vdi QCVN 04:2008 la 0,01 mg/kg ddi vdi nhdm cyclodien. Tuy nhien, cac diem lan can thi ham lugng phat hi?n tuong ddi thap (11,6 ng/g). Trong cac mau phan tich ham lugng chii yeu la dieldrin, chung td mgt phin ldn aldrin da chuyen hda thanh dieldrin ben hon va dgc hon.

Ham lugng nhdm PCB tgi kho la rat cao (7114,2 ng/g). cac mau tram lich cd ham lugng PCB cao ban ban so vdi cac mlu dit Ian can (T2: 104,8 ng/g, T4: 119,1 ng/g, T5: 87,5 ng/g). Day la vimg nudc tryc tiep nhan nudc thai tir cac hogt dgng cdng nghiep va boat dgng dan sinh. Ngoai ra, yeu td dja hinh, tdc dg ddng chay cung co the gdp phan anh

TCHH, T. 51 (I), 2013 Trdn Thj Vdn Thi vd cgng s^

Bdng 2: Ndng dg cac chat phan tich trong cac mlu dit va tram tich Ten hgp

chdt Y-HCH a - H C H 6 - H C H Heptachlor

Endrin Dieldrin

DDE DDD DDT PCB 28 PCB 52 PCB 101 PCB 138 PCB 153 PCB 180 HCHs cyclodien Tong DDT Tong PCB

1 Nong do cac chat phan tich trong man, ng/g Dkh

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0,28 0,29 Nhu vay, du lugng ciia thudc trir sau ca d o va

PCB tai kho ton tru dIu vugt qua gidi han cho phep ciia QCVN 04:2008 ciia Bd Tai nguyen va Mdi trudng, cd kha nang gay d nhiem tren di?ii rgng. Day la nhung kit qua khao sat dIu lien, can tiep tyc kiem tra trong thdi gian dai.

3.2. Sur bien ddi cua tong DDT va tong HCH Theo Hong va cs. [7], nlu ti I? (DDE + DDD)/

ting DDT ldn hon 0,5 thi day la dau hieu chirng td da cd sy phan hiiy cua DDT thanh DDE va DDD trong mdt thdi gian dai, nghTa la ham lugng DDT hi?n cd trong mdi trudng chi la du lugng ciia viec su dung DDT trudc dd. Mat khac, nlu ti 1^ dd nhd ban 0,5 thi cd thi gan day da cd mgt lugng DDT dugc phat thai vao mdi trudng [7]. Cdn theo Strandberg

va cs. [9], neu ti Ie DDT/DDE > 0,5 thi DDT van dang dugc dua vao mdi trirdng trong khoang thdi gian gan day, va neu ti le nay < 0,3 thi trong nhirng nam gin day khdng cd them ngudn phat thai DDT mdi.

Dya theo nhCrng gia thuyet ciia cac tac gia tren, chiing tdi tiln hanh xac djnh ti I? giCra ham lugng DDT va cac dang chuyen hda ciia DDT. Hau het cac ti le (DDE + DDD)/tdn^ DDT dIu Idn hon 0,5 trong cac mlu khao sat. Dieu nay chung td da cd sy chuyin hda giua DDT thanh DDE va DDD. Tuy nhien ddng phan DDT trong cac mau ludn chilm gin 50%i trong tdng cac ddng phan cua DDT nen cd the ndi sy chuyen hda nay xay ra tuong ddi cham.

Mat khac, ti I? DDT/DDE trong cac mau deu Idn hon 0,5; ket qua sa bg nay cho thay rang ngoai

TCHH, T. 51(1), 2013

Iugng DDT cdn ton luu hi$n nay van cd mgt lugng DDT dang dugc dua vao rndi trudng. Nguyen nhan cd thi la do vi?c su dyng bat hgp phap cac loai thuoc

Nghien ciru phdn tich vd danh gid..

trir sau chira DDT cho muc dich canh tac nong nghiep hoac do tir sy phat tan DDT dang dugc bao [|uiin trong ciic chai Ig cdn d kho tdn tru.

BAN DO KET QUA PHAN TJCH MAU KHU VIJC NGHIEN CLtl

CannBy

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Hinh 1: Ham Iugng cac thudc trir sau ca cl Bdng 3: Ty 1? giira ham lugng DDT va cac dang

chuyen hda ciia DDT Mau

Dkh Dl 03.1 T2

DDT/DDE 0,70 1,08 0,89 0,47

(DDE + DDD)/t6ng

DDT 0,73 0,48 0,53 0,68

DDT/tong DDT 0,41 0,52 0,47 0,32 Ham Iugng HCH tai kho tdn trir chira chu yeu dong phan a-HCH (17,3 ng/g), 7-HCH (3,6 ng/g) va cac ddng phan nay da chuyen hda thanh ddng phan P- HCH (7,3 ng/g). Theo nghien cuu ciia Muhayimana va cs. [8], neu ti 1? a-HCH/y-HCH nam trong khoang tir 3 den 7 thi npudn d nhiem chinh la HCH ky thuat, ngugc lai, neu ti le nay nhd hon 1 thi Lindan chinh la ngudn d nhiem HCH. Kit qua tinh

lo va cac PCB (ng/g) tai cac diem kliao sat loan cho thIy ti Ie a-HCH/y-HCH = 4,76 nen cd the du doan rang HCH cd ngudn goc tir HCH ky thuat.

4. KET LUAN

Ket qua phan tich cac mau nudc, dat, tram tich tgi viing cijra sdng Con cho thay cd sy tich luy ciia cac hgp chat PCB va OCP. Ham lugng OCP trong cac mau tram tich ddi vdi tdng DDT tir 2,8 den 8,0 ng/g, long cyclodien tir 3,8 den 9,9 ng/g va ting PCB lir 14,2 din 104,8 ng/g. Ham lugng cua DDT, PCB, cyclodien va HCH trong cac mau dat lln lugt la 2,5 den 1860,3; 3,9 den 7114,2; 2,6 din 159,8 va 20,9 ng/g.

Tai kho ton tru cd ham Iugng tdng OCP (2749,5 ng/g) va tdng PCB (7114,2 ng/g) dIu vugt miic cho phep cua QCVN 04:2008 ciia Bg Tai nguyen va Moi trudng. Ham Iugng cac chit phan tich ddi vai c k mlu nudc, tram tich va dit lan can kho tdn triJ deu

T C H H , T . 51(1), 2 0 1 3

kha thap, rieng c a c m l u t r i m tich d g i n vimg cOra sdng cd ham I u g n g P C B k h a c a o .

Tinh trying b a o cjuan H C B V T V c a cio trong kho ton tru' den thdi diem n a y v i n cdn d u g c kiem soat kha tdt. M u c dg phat thai ra mdi t r u d n g c h u n g quanh thap. Tuy nhien, d e cd d u g c b u c tranh c h u n g ve sy phSn b6 ciia cac h g p c h i t nay, c i n tiep tyc theo doi trong thdi gian dai hon tiQa.

T A I LIEU T H A M K H A O

1. Nguyin Dang Giing ChSu. Xdc dinh ddng thdi du lugng cdc thuoc trir sau ca do va polychlorinaled biphenyls trong muc (sepioteuthis lesioniana) bdng phuang phdp GC-MS, Luin van Th^ic sT Khoa hpc H6a hpc, Trudng D^i hpc Khoa hpc Hui (2009).

:. Uy ban nhSn dSn huy^n Q u i Scm, Ph6ng Tii nguyfin va Moi trudng. Bdo cao hi?n trgng moi trudng nSm 2009 tren dja bdn huyen Qui Son (2009).

3. S. Chen, L. Shi, Z. Shan, Q. Hu. Determination of organochlorine pesticide residues in rice and human and fish fat by simplified two-dimensional gas chromatography. Food Chemistry, 104, 1315- 1319(2007).

t . R. ft. Doong, C. K. Peng, Y. C. Sun, P. L. Liao.

Composition and distribution of organochlorine pesticide residues in surface sediments from the Wu- Shi River estuary. Taiwan, Marine Pollution Bulletin, 45, 246-253 (2002).

Trdn Thf Van Thi vd cong su 5. X. Gong, S. Qi, Y. Wang, E. B. Julia, Chungling Lv.

Historical contamination and sources of organochlorine pesticides in sediment cores from Quanzhou Bay, Southeast China, Marine Pollution Bulletin, 54, 1434-1440(2007).

6. P. M. Hoai, N. T. Ngpc, N. H. Minh, P. H. Viet, M.

Berg, A. C. Alder, W Giger. Recent levels of organochlorine pesticides and polychlorinaled biphenyls in sediments of the sewer system in Hanoi, Vietnam, Environmental pollution, doi:10.1016/j.envpol 2009.09.018 (2009).

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Zhang. Distribution and Fate of Organochlorine Pollutants in the Pearl River Estuary, Marine Pollution Bulletin, 39, 376-382 (1999).

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