6 Tp ch Y hc d phng, Tp XXIII, s 4 (140)

NGUY C SC KHE DO PHI NHIM CHLORPYRIFOS TRN ITNG NNG DN TRNG LA TI THI BNH, VIT NAM: NH GINGUY C SC KHE BNG PHNG PHP XC SUT

Phng Tr Dng1,2*, Nguyn Vit Hng3,4, Trn Th Tuyt Hnh41Cc Qun l mi trng y t, B Y t, Vit Nam2Trung Tm sc khe khe mi trng v cng ng, i hc Griffith, Australia3Trung tm nghin cu Y t cng cng v Sinh thi v B mn Sc khe mi trng,Trng i hc Y t cng cng4 SwissTPH; ILRI; Sandec/Eawag

TM TTNng dn trng la ti Vit Nam c nguy c cao phi nhim vi ha cht bo v thc vt, c bit vichlorpyrifos l loi ln hu c c ng k s dng ph bin nht nm 2009. Nghin cu ny nhm nhgi nguy c sc khe ca chlorpyrifos i vi nng dn trc tip tham gia phun ri loi ha cht ny. Nghincu c tin hnh theo 3 bc: (i) i tng nghin cu c ly mu nc tiu 24 gi phn tchnng trichlorpyridinol (TCP), l sn phm chuyn ha chnh ca chlorpyrifos; sau TCP c chuyni sang liu phi nhim ni ti vi chlorpyrifos (ADD); (ii) ngng liu p ng gy ra tc hi cp tnh ivi h thn kinh (RADD) c thu thp v tnh ton t cc nghin cu dch t hc trn con ngi; (iii) nguyc sc khe c nh gi bng phng php thng k xc sut, s dng k thut Monte Carlo vi 10.000php th, trong ch s nguy c c tnh ton nh t s gia ADD v RADD. Kt qu cho thy liu phinhim nn (ADDB) dao ng t 0,03 1,98 g/kg/ngy, v liu phi nhim sau khi ri (ADDA) dao ngt 0,35-94 g/kg/ngy. Liu phi nhim ton phn (ADDT) dao ng t 0,4 n 94,2 g/kg trng lng cth/ngy. RADD c gi tr dao ng t 5-181 g/kg trng lng c th/ngy. Ch s nguy c (Hazard Quo-tient) c tnh ton cho thy liu phi nhim nn khng gy nguy c sc khe ng k, tuy nhin liuphi nhim sau ri (hoc ton phn) gy nguy c tc hi sc khe vi 33% i tng nng dn tham giatrc tip phun ri chlorpyrifos. Nghin cu can thip cn c tin hnh nhm gim thiu nguy c tc higy ra do ha cht tr su ln hu c.T kha: nh gi nguy c sc khe, thuc tr su, phi nhim, Thi Bnh, chlorpyrifos

*Tc gi: Phng Tr Dnga ch: Cc Qun l mi trng y t, B Y tin thoi: 043846364 Email: ptdzung70@yahoo.com

Ngy nhn bi: 11/4/013Ngy gi phn bin: 15/4/013Ngy ng bi: 8/6/013

I. T VN

Nng dn, chim trn 70% lc lng laong ti Vit Nam, c nguy c cao b nhhng sc khe do phi nhim vi cc ha chtbo v thc vt trong qu trnh s dng v phunri trc tip bng bnh phun tay. Nguy c bphi nhim tng ln do dng c bo h lao ngngho nn, thiu kin thc trong vic s dng,bo qun v tiu hy ha cht bo v thc vtmt cch an ton [1]. Kt qu nghin cu cthc hin bi Murphy v cng s nm 00 chothy 31% s nng dn c iu tra ti Bc VitNam c t nht 1 triu chng nhim c ha

cht bo v thc vt []. Mt nghin cu khcc thc hin bi Dasgupta v cng s nm007 bo co 35% nng dn c nghin cu min Nam Vit Nam c mc suy gimmen cholinesterase trong mu biu hin nhimc cp v 1% nng dn c mc suy gimmen cholinesterase trong mu biu nhim cmn tnh vi ha cht bo v thc vt [3]. Trongs nhim c ha cht bo v thc vt gy rado lao ng nng nghip, s liu bo co tiTrung tm chng c bnh vin Bch Mai chothy ln hu c (Organophosphate Insecticide-OP) chim t l cao nht so vi cc loi hacht bo v thc vt khc [4].

7Tp ch Y hc d phng, Tp XXIII, s 4 (140)

Chlorpyrifos, mt loi ha cht tr sunhm ln hu c c dng ph bin cho cmc ch nng nghip v phi nng nghip(v d: dit tr mi) c a vo th trngtrn th gii t nm 1965 [5]. Ti cc nc angpht trin, chlorpyrifos c nng dn vi quim trang tri nh s dng ch yu trong nngnghip nh trng la, rau v hoa qu [6], v ycng l loi ha cht tr su ln hu c c cp n nhiu do tc hi sc khe i vinng dn gy ra do phi nhim khi pha trn,vn chuyn v phun ri chlorpyrifos [7] [8] [9].Tc hi sc khe do chlorpyrifos gy ra ch yui vi h thn kinh trung ng v thc vt,gim cn nng s sinh, gim chu vi vng uca tr s sinh c m phi nhim v suy gimni tit t sinh sn. Ngoi ra, mc d cha bng chng khoa hc kt lun nhng mt snghin cu dch t hc gn y cho thy c milin quan gia phi nhim chlorpyrifos vinguy c ung th phi v ung th tin lit tuyn[10] [11] [1] [13] [14]. Danh sch ha cht bov thc vt c ng k s dng ca B Nngnghip v Pht trin Nng thn (BNNPTNT)nm 009 cho thy chlorpyrifos c s lng snphm nhiu nht trong s cc loi ha cht trsu thuc nhm Ln hu c [15]. Tuy nhin,cho n thi im ny cha c nghin cu noc thc hin nhm nh gi nguy c sckhe ca loi ha cht ny i vi nng dntrng la ti Vit Nam.

Mc tiu ca nghin cu ny nhm s dngphng php thng k sc xut nh ginguy c sc khe ca chlorpyrifos i vi itng nng dn trng la trc tip phun ri hacht bo v thc vt ti mt x thun nng tnh Thi Bnh, Vit Nam.

II. PHNG PHP NGHIN CU

2.1. a im v i tng nghin cui tng tham gia nghin cu gm 18

nng dn trong tui t 18 n 60 hin angsinh sng ti x V L, Huyn Kin Xng,Tnh Thi Bnh. iu kin chn i tngtham gia nghin cu bao gm: (i) gia nh crung la ring; (ii) l ngi trc tip tham giaphun ri ha cht bo v thc vt trong gia nh;

(iii) c sc khe tt vo thi im nghin cu;v (iv) c kh nng c hng dn trn bao bng ha cht bo v thc vt. Thng tin c bnv c nhn nh tui, gii, chiu cao, cn nng,ngh nghip, din tch trng la, s nm kinhnghim s dng v phun ri ha cht bo vthc vt ni chung v chlorpyrifos ni ring, knng thc hnh pha trn, vn chuyn, phun riv dng c bo h c nhn c thu thp thngqua phng vn v quan st t nhm nghin cu.i tng nghin cu c khm bnh tondin (khm lm sng, lm cc xt nghim cbn v chp X-quang) xc nh c sc khett v c th tham gia vo nghin cu. Trckhi tham gia, i tng c gii thch mctiu, hot ng, li ch v nguy c c th ctrong qu trnh nghin cu c tin hnh, sau k giy cam kt tham gia vo nghin cu.2.2. nh gi phi nhim Chlorpyrifos

Phng php nh gi phi nhim chlor-pyrifos p dng trong nghin cu ny ctham kho t ti liu hng dn ca OECD vUS EPA [16] [17] trong 108 mu nc tiu4 gi c ly t 18 nng dn tham gia nghincu. Mi nng dn c ly 6 mu: 1 mu cly trong vng 1 tun trc khi i tng trctip tham gia phun ri, 1 mu c ly trong lcphun ri, v 4 mu c ly trong vng 10 gisau ngy phun ri chlorpyrifos. Ngoi ra 1mu nc tiu 4 gi cng c ly t itng khng phi nng dn, ang sinh sng tiH Ni v khng tip xc vi ha cht bo vthc vt lm mu kim tra mc tp nhimchlorpyrifos t dng c ly mu v vn chuyn,cng nh xc nh liu phi nhim nn trongcng ng. Mu nc tiu c bo qun nhit -4oC trong vng 4 gi sau khi c lycho n lc phn tch.

Mu nc tiu 4 gi c phn tch ti phngxt nghim ca Trung tm Nghin cu khoa hcv Gim nh Php y (QHFSS), Queensland, Aus-tralia. Ch s c phn tch: 3,5,6-trichloro--pyridinol (TCP) l ha cht chuyn ha chnh cachlorpyrifos. Phng php phn tch s dng tinx l v enzyme sinh hc (-glucuronidase chngH-1), chit sut bng dung dch methyl-tert-butyl-ether/hexane (30%), sau hm lng TCP cchit xut v phn tch bng LC/MS (liquid chro

8 Tp ch Y hc d phng, Tp XXIII, s 4 (140)

matography/mas spectrometry). Ngoi ra Crea-tinine trong nc tiu cng c phn tch chun ha khi o lng hm lng TCP trongnc tiu 4 gi.

Liu phi nhim chlorpyrifos (AbsorbedDaily Dose: ADD) c o lng t hm lngTCP trong nc tiu theo cng thc bo cotrong nghin cu ca Mage v cng s nm004:

ADD = CCnCFRmw/BWTrong , ADD: liu phi nhim chlorpyrifos

hng ngy (g/kg/d); C: hm lng TCP (g/gcreatinine); Cn: lng bi tit creatinine qua nctiu (g/d); CF: ch s chuyn ha t chlorpyrifossang TCP (1/70%=1.4); Rmw: t l khi lngphn t gia chlorpyrifos v TCP; BW: cn nngca i tng c ly mu.

C 3 mc phi nhim chlorpyrifos co lng, bao gm: (i) liu phi nhim nn(ADDB) l liu phi nhim trong sinh hot bnhthng trc khi phun ri; (ii) liu phi nhimdo phun ri (ADDA) l liu phi nhim c olng trong khi phun ri v trong vng 10 gisau khi phun ri; (iii) liu phi nhim tng(ADDT) l liu phi nhim tng ca liu phinhim trn.2.3. nh gi liu p ng chlorpyrifos v tchi sc khe.

S liu v ngng liu ca chlorpyrifos gytc hi cho sc khe c thu thp t cc bo codch t hc v mi lin quan gia liu phi nhimchlorpyrifos v tc hi sc khe nh nhim cthn kinh trung ng, thn kinh thc vt, gimcholinesterase trong mu, bin i hormone sinhsn, bnh mu v ng h hp,Cc ti liukhoa hc cng b c tm kim h thng trncc trang web khoa hc PubMed v ToxNet vit kha chlorpyrifos v health effect hocdose-response relationship. Trong trng hpliu phi nhim c bo co di dng hmlng TCP trong nc tiu, liu phi nhim trctip c tnh ton s dng cng thc m ttrong mc .. Ngng liu gy tc hi sc kheca chlorpyrifos c vit tt: RADD v cng cn v o lng: g/kg trng lng c th/ngy.

2.4. nh gi nguy c sc khe s dngphng php xc sut

Ch s nguy c (Hazard Quotient: HQ) ctnh ton nh t s gia liu phi nhim c thv liu tham kho (Reference Dose) c tnhton t ngng liu gy ra tc hi sc khe(NOEAL hoc LOEAL), tuy nhin trong trnghp ny HQ c tnh l t s gia ADD/RADD.Khc vi phng php nh gi nguy c imtruyn thng (HQ = t s gia mt gi tr i dincho liu phi nhim, v d s trung bnh, so snhvi gi tr ca liu tham kho c tnh ton chyu t cc nghin cu thc nghim), ch s nguyc trong nghin cu ny c tnh ton bi s sosnh phn b xc sut ca gi tr ca liu phinhim (ADD) v phn b xc sut ca gi tr cangng liu gy ra tc hi sc khe (RADD) cs dng k thut Monte Carlo vi 10.000 phpth. Vic tnh ton c thc hin trn phn mmng dng Crystal Ball 000. Vi qui c: nu chs nguy c (HQ) >1, nguy c gy ra tc hi visc khe ca liu phi nhim c xc nh, do kt qu tnh ton nh m t trn s chochng ta bit xc sut (%) ch s nguy c (HQ)c gi tr ln hn 1, tng ng vi xc sut cnguy c i vi tc hi sc khe gy ra do liuphi nhim.

III. KT QU3.1. M t i tng nghin cu

Thng tin c bn v i tng nghin cu vthc hnh s dng ha cht bo v thc vt ctrnh by trong Bng 1. i tng tham gianghin cu c tui t 19 n 59 tui (trungbnh: 4,6,7), bao gm 13 nam v 5 n. a si tng (13/18) c trnh tiu hc hoc trunghc c s, ngh nghip chnh l nng nghip. Chs nhn hc (BMI) trung bnh ca i tngnghin cu: 0.. Kt qu khm tng th ti bnhvin cho thy tt c cc i tng nghin cu ctnh trng sc khe tt v cc ch s xt nghimbnh thng, c sc khe lao ng. Din tchtrng la ca gia nh i tng tham gia nghincu t 160m n 430m (trung bnh:3100155m).

9Tp ch Y hc d phng, Tp XXIII, s 4 (140)

Bng 1 Thng tin c nhn v thc hnh s dng chlorpyrifos

c im n vTui 42,6 (19-59) tuiGii

Nam 13 ngiN 8 ngi

Trnh vn ha

Tiu hc, trung hc c s 13 ngi

Trung hc 4 ngi

Cao ng 1 ngi

Ch s nhn hc (BMI) 20,2 (16,6-24,7)

Din tch ng la 3.100 (1.620-4.320) m2

Kinh nghim canh tc la v s dng ha cht bov thc vt 23 (4-40) nm

Mc s dng chlorpyrifos 104 (54-144) grams

Thi gian phun ri chlorpyrifos 5,2 (3-7,5) gi

Din tch c th c che ph bi trang b bo hc nhn 80% (63,5-84,8)

3.2. Mc phi nhim chlorpyrifos trn itng tham gia nghin cu

3.2.1. Liu phi nhim nn (ADDB) Liu phi nhim nn (ADDB) khi cha

phun ri chlorpyrifos dao ng t 0,03 1,98microgram/kg cn nng/ngy (g/kg/ngy) cgi tr trung bnh: 0,4 g/kg/ngy. Liu phinhim trung bnh tnh theo s ngy trc khiphun ri dao ng t 0,06 1,74 g/kg/ngy.Liu phi nhim cao nht (1,74 g/kg/ngy)c o lng ngy ngay trc khi phun ric thc hin v liu phi nhim ny cao hn

so vi liu phi nhim o lng c ccngy trc (0,11-0,38 g/kg/ngy) (p

30 Tp ch Y hc d phng, Tp XXIII, s 4 (140)

3.2.3. Liu phi nhim ton phn (ADDT)Liu phi nhim ton phn (ADDT) c

tnh ton bng tng liu phi nhim nn(ADDB) v liu phi nhim do phun ri(ADDA) (Bng ). ADDT dao ng t 0,4 94,g/kg/ngy v c gi tr khc bit khng ngk so vi ADDA, iu ny do gi tr ng gpca ADDB vo liu phi nhim ton phn rtnh. Phn b sc xut gi tr ca ADDT cth hin trong Hnh , trong gi tr trung v(50th percentile): 9,3 g/kg/ngy thp hn lnso vi gi tr trung bnh (19,7 g/kg/ngy), do

phn b sc xut ca ADDT l phn b lchchun. Gi tr thp nht ca ADDT 5th per-centile: 0,9g/kg/ngy, trong khi gi tr cao nht 95th percentile: 97,8 g/kg/ngy. ng phnb hi quy tuyn tnh trong khong gi tr t5th-95th percentile c h s tng quan cao(r=0,94). Cng thc hi quy tuyn tnh nhsau:

CF(%) =44,log(ADDT)+7,3Trong , CF: t l phn b sc xut cng

dn, ADDT: liu phi nhim ton phn vichlorpyrifos.

Bng 2. Liu phi nhim ton phn vi Chlorpyrifos (ADDT) c tnh ton t hm lng TCP trong nc tiu

Nngdn

TCP (g/g Creatinine) trong nc tiu ADDT(g/kg/ngy)Trc

phun riNgy

phun ri24 gi sauphun ri 48 gi 72 gi 96 gi 120 gi Tng

F1 0,82 29,90 73,7 61,2 46,1 37,5 29,7 279 37,3F2 1,84 1,57 2,2 3,4 2,4 2,1 2,0 16 1,9F3 0,78 19,90 35,7 26,2 24,8 15,2 7,7 130 8,7F4 3,48 7,12 12,6 12,9 11,2 9,2 13,9 70 5,4F5 1,17 25,10 46,1 37,9 27,7 15,4 11,5 165 19,8F6 0,68 14,40 28,7 26,8 20,7 18,5 25,2 135 13,7F7 0,67 34,10 182,0 108,0 95,1 56,7 27,1 504 51,6F8 1,65 35,20 57,0 48,1 47,6 25,8 0,3 215 24,7F9 0,76 3,65 5,1 4,7 3,0 1,0 0,6 19 1,7

F10 3,76 97,40 173,0 148,0 135,0 85,0 34,9 678 94,2F11 5,27 3,64 12,9 9,5 8,6 7,5 3,6 51 6,3F12 3,52 1,74 4,4 3,2 4,3 5,2 7,0 29 1,7F13 1,21 24,50 35,7 26,1 15,3 14,6 7,4 125 7,9F14 14,7 62,10 98,4 76,7 52,7 39,9 22,5 367 49,4F15 4,00 4,91 19,2 15,2 9,5 8,4 2,5 64 7,8F16 2,15 28,40 48,6 36,4 36,9 24,4 16,9 194 15,3F17 2,00 19,80 19,1 17,9 9,0 0,3 1,0 69 7,4F18 1,26 0,70 0,1 0,45 0,0 0,2 0,2 3 0,4

3.3. Liu p ng tc hi sc khe ca chlor-pyrifos

Nh m t trong Mc .3, ngng liup ng ca chlorpyrifos vi tc hi sc khe(RADD) c thu thp v tnh ton t ccnghin cu dch t hc, kt qu c trnh bytrong Bng 3. Tc hi i vi h thn kinh lnh hng cp tnh v tiu biu ca cc ha

cht bo v thc vt nhm ln hu c, bao gmc chlorpyrifos, do ngng liu gy tc hithn kinh thu thp c t cc nghin cu dcht hc c s dng lng gi nguy c sckhe ca chlorpyrifos i vi nng dn s dngv phun ri trc tip chlorpyrifos. Ngng liugy tc hi thn kinh (RADD) c gi tr daong t 5-181 g/kg/d [18] [19] [0] [1] [].

31Tp ch Y hc d phng, Tp XXIII, s 4 (140)

Bng 3. Ngng liu p ng ca chlorpyrifos vi tc hi h thn kinh t kt qu nghin cu dch t hc trn con ngi

Ti liu thamkho

i tng nghin cu TCP trongnc tiu

Liu phinhim ni

ti (ADDD)*

Liu phinhim c

i(LADDD)** Tc hi

(Tui trung bnh) (g/L, or g/gcreatinine)(g/kg/ngy) (g/kg/ngy)

Steenlan et al.,2000 Cng nhn dit mi 629,5 g/L 35,7 11

Vn v tr nh,trng thi cm gic,mt mi v mi c

Dick et al., 2001 Cng nhn phun ri hacht bo v thc vt 200 g/g 15,6 4,9nh hng b mycm gic

Albers et al.,2004a

Cng nhn nh my snxut ha cht bo vthc vt

192,2 g/g 15,6 6.2 c ch BuChE

Garabranti et al,2008

Cng nhn nh my snxut ha cht bo vthc vt

>110 g/g 5 2 c ch Bu ChEc ch RBC ChE

Albers et al, 2007Cng nhn nh my snxut ha cht bo vthc vt

576-627g/ngy 15,6-17 6.2-6.7

Liu nng nhhng n thnkinh ngoi bin

Farahat et al, 2011Nng dn 3,161 g/g 181 3 c ch AChE

Phn b xc sut ca ngng liu gy tc hii vi h thn kinh cachlorpyrifos c thhin trong Hnh . RADD mc 5th percentile

c gi tr: 3, g/kg/ngy, c cn nhc sdng nh ngng liu hoc liu tham kho chotc ng cp tnh i ca chlorpyrifos.

Hnh 2. Phn b xc sut liu phi nhim ton phn (ADDT) v ngng liu gy tc hi sc khe (RADD).

3 Tp ch Y hc d phng, Tp XXIII, s 4 (140)

3.4. Nguy c sc khe ca chlorpyrifos ivi nng dn trng la

Hnh 3 trnh by phn b xc sut gi tr cach s nguy c (Hazard Quotient: HQ) ctnh tnh ton t t s phn b liu phi nhim

(ADDB, ADDT, bo co trong mc 3..1-) vphn b ngng liu gy tc hi cp tnh vi hthn kinh (RADD, bo co trong Mc 3.3) sdng k thut Monte Carlo Simulation (MCS)vi 10.000 php th.

Hnh 3 Phn b xc sut ch s nguy c (HQ) tnh ton s dung MSC vi 10.000 php th.

Phn A: ch s nguy c vi liu phi nhimnn (ADDB); Phn B: ch s nguy c vi liuphi nhim ton phn (ADDT)Kt qu cho thy, vi mc phi nhim nn100% gi tr caHQ 1 l 33% (xem Biu 3), iu ny tng ng vi kt qu c ti33% nng dn tham gia phun ri chlorpyrifosc th b tc hi cp tnh i vi h thn kinhv ngng liu ti thiu cho nguy c ny cghi nhn l: 3, g/kg/ngy (5th percentile cangng liu p ng c bo co trong Mc3.3).

33Tp ch Y hc d phng, Tp XXIII, s 4 (140)

IV. BN LUN

Trong nghin cu ny, trung bnh i tngc 3 nm kinh nghim canh tc trng la vs dng ha cht bo v thc vt. Mc chlorpyrifos nguyn cht c pha trn v sdng cho phun ri ti thi im nghin cu t54 n 144g (trung bnh: 1045g), v thi gianphun ri chlorpyrifos t 3 n 7,5 gi (trungbnh: 5,0,3 gi). Tt c cc i tng nghincu u khng c phng tin bo h lao ngc nhn t tiu chun v s dng m cng,o di tay, qun di, khu trang thng hockhn che mt. Din tch c th c bo vbng cc phng tin bo h trn (tnh tontheo hng dn ca Graber v cng s, 1997)[3] chim t 65% n 85% (trung bnh:801.6%).

Cc liu phi nhim nn (ADDB) cho ccgi tr rt khc nhau ty vo giai on trcv sau phun ri chlorpyrifos. L gii cho skhc bit ny c th do i tng tham gianghin cu phi nhim vi chlorpyrifos khimua bn, vn chuyn, bo qun v s dngcho vn rau ti nh trc khi s dng chocanh tc la. Hu ht nng dn ti a imnghin cu cho bit h thng mua ha chtbo v thc vt ch 1 ngy trc khi phun ri trnh phi bo qun trong nh. Mc liuphi nhim tng cao nht 4 gi sau khi ricng c ghi nhn trong cc nghin cutrc y [6] [8], tuy nhin thi gian liuphi nhim tr v mc phi nhim nn ckhc bit so vi mt s nghin cu trc.Nghin cu c thc hin trn i tngnng dn s dng chlorpyrifos ca Sri-Lankav USA cho thy khong thi gian ny l 96gi, trong khi nghin cu c thc hin trni tng nng dn ca Ai Cp cho thykhong thi gian ny l 168 gi [4].

Kt qu Hnh 3 cho thy nguy c cao ivi tc hi sc khe gy ra do chlorpyrifos,mt loi thuc tr su ln hu c, trn itng nng dn trng la, ngi tham giaphun ri trc tip. Kt qu ny ph hp vi ktqu nghin cu dch t hc c thc hintrc y. Nghin cu ca Murphy v cng s(00) trn i tng nng dn ti Min Bc

Vit Nam bo co 31% nng dn c iu trac t nht mt triu chng cp tnh ca nhimc ha cht bo v thc vt, v nghin cuca Dasgupta v cng s (007) trn i tngnng dn Min Nam Vit Nam cho thykhong 35% nng dn c lm xt nghimcholinesterase b nhim c cp tnh i viln hu c.

y l nghin cu u tin s dng phngphp nh gi nguy c sc khe dng phngphp thng k xc xut i vi tc ng caha cht bo v thc vt i vi sc khe nghnghip nng nghip. Kt qu nghin cu chothy u im trong vic s dng phng phpnh gi nguy c sc khe cho c lnh vcnghin cu, can thip v chnh sch. Khc vinghin cu dch t hc, nh gi mi lin quangia nguy c ca mt vn v sc khe(bnh) vi mt tc nhn mi trng (ha cht,vt l, sinh hc), nh gi nguy c sc khec th tr li cho chng ta cu hi v mc nguy c ca vn sc khe (bnh hoc nhmbnh) gy ra do tc nhn mi trng ngngliu c th. Phng php nh gi nguy c sckhe s dng thng k xc sut c u imhn phng php nh gi nguy c sc khetheo im truyn thng do s dng phn b gitr ca phi nhim v nguy c liu p nghn l s dng mt im i din cho cc gitr ny trong tnh ton ch s nguy c. Ngoira trong nghin cu ny ch s dng ngngliu thc t c bo co t cc nghin cudch t hc trn con ngi ch khng phi tnghin cu thc nghim ng vt.

Tuy nhin, nghin cu cng cn c nhnghn ch nht nh nh: c mu nh do hn chqui m v kinh ph, nhng hn ch ny phnno c gii quyt khi nghin cu s dngm hnh Monte Carlo vi 10.000 php th tng c mu v tnh a dng trong tnh tonkt qu. Hn ch th nhn thc c trongnghin cu l phng php nh gi nguy csc khe dng kt qu nghin cu dch t hctrn con ngi ch c th c tin hnh khic cc nghin cu ny c cng b,nu khng nghin cu khng c kh nng tnhton liu p ng nh trong nghin cu ny thc hin.

34 Tp ch Y hc d phng, Tp XXIII, s 4 (140)

V. KT LUN

Chng ti p dng thnh cng phngphp xc sut nh gi nguy c sc khe cachlorpyrifos i vi nng dn trc tip tham giaphun ri loi ha cht ny mt x ca tnhThi Bnh. Kt qu cho thy liu phi nhimnn (ADDB) khng gy nguy c sc khe ngk, tuy nhin liu phi nhim sau ri (hoc tonphn) gy nguy c tc hi sc khe vi 33% itng nng dn tham gia trc tip phun richlorpyrifos. y l nghin cu u tin sdng phng php nh gi nguy c sc khedng phng php thng k xc sut i vi tcng ca ha cht bo v thc vt i vi sckhe ngh nghip nng nghip ti Vit Nam.Kt qu nghin cu cho thy u im trong vics dng phng php nh gi nguy c sckhe cho c lnh vc nghin cu, can thip vchnh sch. Nghin cu can thip cn c tinhnh nhm gim thiu nguy c tc hi gy rado ha cht tr su ln hu c.

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HEALTH RISK DUE TO EXPOSURE TO CHLORPYRIFOS FOR FARMERS INTHAI BINH: PROBABILISTIC RISK ASSESSMENT

Phung Tri Dung1,2, Nguyen Viet Hung3,4, Tran Thi Tuyet Hanh41Vietnam Health Environment Administration, Ministry of Health2Center for environmental and community health, Griffith University, Australia3Center for Pubic Health and Ecosystem Research and Department of Environmen-tal Health, Hanoi School of Public Health4SwissTPH, ILRI, Sandec/Eawag

Farmers in Vietnam are at high risk of expo-sure to pesticides, especially with chlopyrifos, themost common insecticide registered for use in009 in Vietnam. The purpose of this study wasto assess the health risks of chlorpyrifos exposurein farmers who were pesticide applicators.

The research method included three steps: (i)4-hour urine samples taken from farmers toanalyse trichlorpyridinol (TCP), the main metabo-lite of chlorpyrifos, and then TCP was convertedto Absorbed Daily Dose (ADD); (ii) dose-re-sponse (RADD) corresponding to acute effects onthe nervous system was obtained and recalculatedfrom epidemiologic studies on human population;(iii) the health risk of chlorpyrifos with farmerswas evaluated using probabilistic health risk as-sessment approach with 10,000 trials simulated byMonte Carlo technique.

The results showed that the baseline exposure

level (ADDB) ranged from 0.03 - 1.98 g/kg/d,and post-application exposure level (ADDA)ranged from 0.35 - 94 g/kg/d. The total exposurelevel (ADDT), ranged from 0.4 - 94. g/kg/d.Dose-response corresponding to neurological ad-verse effects (RADD) ranged from 5-181 g/kg/d.The Hazard Quotient calculated from ADD andRADD revealed that the baseline exposure leveldid not contribute to a significant adverse effect,however the post-application and total exposurelevels caused a high risk of adverse effects tofarmers who were pesticide applicators at 33%. Aneeds assessment and intervention studies need tobe conducted to explore methods to reduce therisks due to chlorpyrifos exposure among farm-ers.

Keyword: Health risk assessment, pesticide,exposure, Thai Binh Province, chlorpyrifos.