LY LUAN Q U A N L Y - P H A T TRIEN
GOP PHAN DANH GIA T H U C TRANG
o NHI£M CHAT DA CAM/DIOXIN
TS. LE KE SON
Phd Tong Cue truang - Tong cue Mdi truang
T
'heo nghien cUu cue mot sd nha khoa hgc My va Viet Nam, hien nay d Viet Nam cdn tdn tai 3 vung d nhiem nang chat da cam/dioxin (vung ndng) la san bay Da Nang, san bay Bien Hda va san bay Phu Cat (Schecter, Hatfield, Oy ban 10-80, Van phdng Ban Chi dao 33, 2006).Vdi san bay Da Nlng, da cd kha nhieu nghien eUu va CO the danh gia tdng the qui md va mUc do d nhidm dioxin.
Nhung dd'i vdi san bay Phu Cat va Bien Hda, can thiet phai cd nhUng nghien cUu bd sung.
San bay Phu Cat da tUng luu giu 17.000 thung chat da cam, 9.000 thung chat trang, va 2.900 thung chat xanh (US DOD report, 2007). Tai khu trung tam phia Ddng cua can cU cd nhieu kenh rach thoat nude chay tU khu vuc rira may bay chUa chat diet cd den cac hd A, B va C.
San bay Bien Hoa la mot can eir chinh cua chien djch Ranch Hand, da luu giU khoang ban 98.000 thung chat da cam, 45.000 thung chat trang va 16.000 thung chat xanh (US DOD report, 2007). Han 11.000 thung chat diet cd da dugc van chuye'n tU Bien Hda trong chien djch Pacer Ivy vao nam 1970. Cac nghien cUu trude day cho thay mUe do d nhidm dioxin tai Bien Hoa la rat cao (Schecter va cdng su 2001, 2002; Hatfield va Uy ban 10-80, 2007). Nude thai chay tu dudng bang la nguyen nhan gay d nhidm khu vuc phia eud'i s§n bay va cac hd lan can trong va ngoai san bay.
Chung tdi da tien hanh nghien cuV miu dat va tram tich, cu the nhifsau:
- Cd 79 miu (67 miu dat va 12 miu tram tich) dugc lay d khu vuc phia Ddng cua sSn bay Phu Cat va cac hd A, B va C, la nai tiep nhan ddng xa thai cua sSn bay (45 miu da dugc phan tich xac djnh dioxin).
- Cd 125 miu (bao gdm 114 miu dat va 11 mau tram tich) dugc lay tai 3 khu vuc trong san bay Bien Hda (khu vuc Z1, khu vuc Tay Nam va khu vuc Pacer Ivy).
- Dat va tram tich dugc phan tich tai Trung tam Nhiet ddi Viet - Nga bang phuang phap 45 TQSB 01:2007 (dugc phat trien dua tren phuang phap cua Cue Bao ve Moi trudng My - EPA 8280A), tren may sac ky khf - khdi phd do phan
Cang hang khdng Phu Cat ngay nay ANH: ST
giai thap.
- Mot sd miu dugc phan tich tai Phdng phan tfch di- oxin AXYS (Canada) de' ddi chUng.
- Toan bd miu dat va tram tich dugc them chat chuan cd gan ddng vj Carbon (tetrachlorodioxin, tetrachlorofuran, pentachlorodioxin, pentachlorofuran, hexachlorodioxin, hexachlorofuran, heptachlorodioxin, heptaehlorofuran va octachlorodioxin) trude khi phan tfch. Miu dat dugc chiet soxhiet va sau dd la chiet Idng - long bang each lac vdi dung mdi. Toan bd dich chiet dugc dua qua cac cdt lam sach trude khi bam len may sac ky khf ghep ndi khdi phd.
Ndng do dioxin dugc tinh toan theo TEQ va TEF do WHO quy dinh (Van de Berg va cs, 1998).
- Viec kiem tra va dam bao chat lugng quy trinh phSn tich tai Phdng phan tich dioxin AXYS bao gdm viec phSn tich va xac djnh he sd thu hdi, kie'm tra do chinh xac cua dung dich chuan, phan tich miu chuan cd ndng do chat can phan tich da dugc ehUng thuc (Certified Reference Materials, CRMs), va tham gia vao chuang trinh kiem tra lien phdng thi nghiem (Bert van Bavel, 2005). Ket qua dd'i chUng cua 2 phdng thi nghiem la tuang dd'i phu hgp.
Ket qua phan tich dioxin dsan bay Phu Cat cho thay:
Cd 7 khu vuc dugc lua ehgn de' danh gia mUe do d
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nhidm dioxin trong san bay Phu Cat (kho ehUa, nap, vanh dai, rira, xd ly nude thai, be sa lang, cac hd A, B, C; gdc Ddng Nam cua san bay).
Cd 11 miu tai khu vuc kho chUa cd ndng do dioxin trong khoang tU 345 den 236.000 pg/g TCDD. Miu cd ndng do cao nhat dugc lay d phia dudi cua them de may bay va d do sau 10 - 30 cm. Hau het cac mau lay tai khu vuc kho chUa cd ndng do dioxin vugt qua 1000 pg/g va TCDD chiem tren 97% tren tdng TEQ.
Cd 7 miu dugc lay tU khu vuc nap de phan tich dioxin.
Ndng do 2,3,7,8-TCDD trong miu dat tai khu vuc nay nhd ban nhieu so vdi khu kho ehUa va nam trong khoang tU 2,24 den 850 pg/g. Hai miu lay tU dau ra cua he thdng ranh thai trong khu nap cd ndng do dioxin cao nhat: 840 pg/g TCDD va 850 pg/g TCDD. Ndng do dioxin trong tat ca cac miu tai khu vuc nay deu nhd hon ngudng cho phep 1000 ppt (pg/g) trong miu dat,
Khu vuc vanh dai la mot vung ddi ddc cd nhieu ranh nude tu nhien. Mot miu dugc lay ngay tai chan ddc cd ndng do dioxin 2.890 pg/g TCDD.
Khu vuc rifa cd dien tich 36.000 m^ dugc phu nhua dudng va dugc sir dung de ri!ra may bay, xe eg va cac thiet bi phun chat diet cd. Nude tai khu vuc nay dugc chay qua mot he dng dan tUng bac xudng be sa lang va he thdng xd ly nude thai. Ndng do dioxin trong cac miu tai day kha thap, dao ddng trong khoang tU 0,7 den 4,1 pg/g TCDD.
Cac hd A, B va C la be chua cudi cung cua nude thai tu san bay Phu Cat, sau khi di qua be sa lang va he thdng XLT ly. Cac miu nay deu cd ndng do dioxin thap, trong khoang tU 3,0 den 22,9 ppt TCDD,
Ndng do 2,3,7,8-TCDD trong tat ca cac mau lay d khu Ddng Nam deu thap, trong khoang tU 0,66 pg/g den 12,2 pg/g TCDD (5,63 den 236 pg/g TEQ). Ty le phan tram TCDD tren tdng TEQ trong cac miu cung rat thap, khoang tu 2 den 67,8%.
Ket qua phan tich mau lay tai san bay Bien Hoa cho thay:
Miu dugc lay tai gde Tay Nam cua san bay (cdn dugc ggi la khu vuc mdi phat hien, ky hieu khu A); khu vuc Pacer Ivy (gdc Tay Nam cua dudng bang, ky hieu khu B); khu Z1 (diem ndng); vung vanh dai cua khu Z1, bao gdm vung dat thap va cac ao, hd, kenh rach thoat nude d phia Nam (ky hidu khu C).
Tai khu A, 39 miu dat dugc lay tai 31 die'm va d do sau khac nhau tube mat cho den do sau 1,5 m, Cd16miu da duac phan tich va cd 5 mau cd ndng dd dioxin Idn ban 1.000 pg/g TEQ,
Phan tich 2 mau lay tai phia Tay cua khu B cd ndng do dioxin cao (2.000 va 22.300 pg/g TCDD), Mau dat lay
tai phia Tay va phia Nam cija dudng bang cd ndng do dioxin thap ban. Miu tram tich dugc lay tai cac hd, ao va ranh thoat nude xung quanh vj tri nay theo hudng do ddc cua dudng bang va ddng chay, Ndng do dioxin trong cac miu tram tich tU 1,090 - 5,900 ppt TEQ. Phan tram cua TCDD tren td'ng TEQ trong mot vai miu Idn han 90%.
Khu vuc gdc phia Nam cija san bay cd dia hinh phUe tap vdi rat nhieu ao nudi ca va hd. Muc do d nhidm dioxin rat khac nhau tai tUng khu vuc va cd xu hudng tap trung nhieu tai he thdng ranh thoat nude d eud'i ddng chay
Khu Z1, da dugc xac djnh la diem d nhidm dioxin nang nhat trong san bay Bien Hda (Bao cao Z1, 1997).
Phan tich 52 miu dat tai 43 dja die'm trong vung vanh dai cua khu Z1 cho thay ndng do dioxin trong cac mau tai khu vuc ebon lap cua khu Z1 dao dong trong mot khoang Idn, tu 22,6 - 13.300 ppt TEQ, Miu lay tai khu vuc Tay Nam cua khu Z1 cd ndng do dioxin cao, Trong miu 08VNBH141-3 tai do sau 30 - 60 cm, ndng do dioxin la 8,310 ppt,
Ket qua phan tich 3 miu tram tich lay tai hd chua nude gan khu Z1 cd ndng do dioxin cao nhat dugc tim thay d miu 08VNBH155 (2,240 ppt TEQ), la miu lay tai ao nudi ca, va trong miu 08VNBH157 (1790 ppt TEQ) lay tai gan khu vuc nudi trdng thuy san, Cac miu tram tich khac dugc lay tUcac kenh thoat nude ndi vdi ao nudi ca. Cac miu nay cd ndng do dioxin nhd (20,9 ppt va 22 ppt TEQ). Nhu vay, phan Idn cac mau trong ao deu cd ndng do vugt tieu chuan 150 ppt.
De danh gia chung tinh hinh 6 nhidm dioxin trong mdi truang nude, chung toi cung so sanh vdi mot sd ket qua nghien cuu khac. Schecter va cac cdng su (2001) da phan tich ndng do dioxin trong miu tram tich tai hd Bien Hiing 1 va hd Bien Hung 2. Ndng do dioxin trung binh tai hai hd la 177 pg/g TCDD (Schecter va cac cdng su, 2001). Nghien cCru cua Hatfiled va uy ban 10-80 (2006) cho thay ndng do dioxin cao nhat la 797 pg/g TCDD; ndng do dioxin trong mot miu tram tich khac lay tai hd phia Nam san bay la 244 pg/g TCDD; ndng do dioxin trong dat cao nhat tai hd nay la 284 pg/g TCDD (TCDD chiem 97%, 294 pg/g TEQ).
Cac ket qua nay chung td su lan truyen cija dioxin trong mdi trudng do anh hudng cija mua 10 va eud'i cung tich tu tai cac thijy vuc.
Tom lai, qua phan tich miu dat va tram tich miu dat, tram tich d khu VL/C Phii Cat va Bien Hoa, co the nhan dinh rang:
- Ndng do dioxin tai mot sd diem trong san bay d Phu Cat cao ban ndng do cho phep nhung chi gidi ban trong mot pham vi khdng Idn, it anh hudng den mdi trudng va con ngudi trong cac vung gan san bay. Tuy nhien, vin can
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developing countries: a potential source of polychlorinated dibenzo-p- dioxins and polychlorinated dibenzofurans (PCDD/Fs). Environmental Sci- ence and Technology Vol. 37, No. 8:1493-1502.
2. Schecter A., Dai LC, Paepke 0., Prange J., Constable JD., Matsuda M., Tao VD., Piskac SA. 2001. Recent dioxin contaimianated from Agent Orange in resident of Southern Vietnam City JOEM 43.5, 435-443.
3. Schecter A., Quynh NT, OAvukM., Paeke 0., Maiisch R., Con- stable 1.2003. Foods as source of dioxin exposure in the residents of Bien Hoa city, Vietnam. JOEM, 45/8,781-788.
4. US EPA.2001. Database of sources of environmental relases of dioxin and dioxin-like compounds in US.
5. VanBavelB., Lindstrom G., DeBoerJ., FiedlerF.2007. Feasibility training and performance in interiaboratory comparision study within UNEP assessment and capacity building program for the Stockholm convention on POPs in developing countries. Organohalogen compounds. 69,1285-1288.
6. Young AL, Presentation in the Vietnam-US workshop in Hanoi, June 2007.U
G O P PHAN DANH GIA... (Tiep theo trang 16)
thi/c hien cac giai phap khu tru va xd ly triet de.
- 0 nhidm dioxin d sSn bay Bien Hda va vung lan can phUe tap hon. Ndng do dioxin cd ngudn gdc tU chat diet cd do My sir dung tai san bay Bien Hda cd ndng do rat cao, phSn bo khdng ddng ddu d cac vj tri khac nhau va do sau khac nhau.
- Dioxin tu vung d nhidm da lan tda theo nude mua chay tran tu khu vuc d nhiem den cac ao hd trong va ngoai san bay Bien Hda; ndng dd dioxin trong tram tich tai cac hd nay cao hon ndng dd cho phep, la ngudn gdc gSy phoi nhidm ddi vdi cac ddng vat thuy sinh va thdng qua ddng vat thijy sinh gay phai nhi§m d ngudi.
- Can phai tinh toan lai ke hoach, qui md, ky thuat xd ly dioxin tai san bay Bien Hda va cac hd trong va ngoai san bay Bien Hda.a
DINH CHINH
Trong chuyen muc Thuc tidn - Kinh nghiem - Ddi mdi, sd thang 5/2010, trang 24, ddng thU 5, thU 6 tU trdn xudng trong hop ky thuat cua bai "ATLD tren To hop Cong trinh
Keangnam Hanoi Landmark Tower: Ky lue ve chieu cao
• Kyluc ve sal pham" c\ia tac gia Van Khudng, cum tU "tCr khau tochiyc bg may lam cong tie BHLD", xin sCra lai la
"tif khau tochH/c bg may lam cong tic BHLD". Tai trang Muc lue, phan tieng Viet, d chuydn muc Khoa hgc - Cdng nghe - Chuyen giao, ddng thU 11 tU tr6n xudng, cum tU "Kha nang tieu thu va phan buy sinh boat chat thai rin...", xin dgc lai la "Kha nang tieu thu va phan hwy sinh hgc chat thai rin...". Thanh that xin I6i dgc gia.
TAP CHi BHLO
DAC DIEM MOI TRl/ClNG...
(Tiep theo trang 19)
- Do am: 79,5% miu do dd am khdng dat TCVSCP 18/22 CO sd hau het cac vi tri do cd do am khdng dat tieu chuan ve sinh cho phep.
- Anh sang: d tat ca cac ca sd dugc do deu cd nhieu diem anh sang khdng dat TCVSCP Cd 11 ca sd, tat ca cac miu do anh sang deu khdng dat tieu chuan ve sinh. 86,8% miu anh sang khdng dat tieu chuan ve sinh cho phep.
- Tieng dn: 83,1% miu do tieng dn khdng dat tieu chuan ve sinh cho phep. Cd 10 co sd cd tat ca cac vi tri do mUc dn deu khdng dat tieu chuan ve sinh cho phep, 7 co sd cd mUc dn tU 90 dBA trd len.
Kien nghj:
Bd tri nha xudng hgp ly, tach rieng tUng khu vuc lam vide. Miia he nen bd tri quat cdng nghiep thdi suang de giam ndng trong MTLD. Tang cudng anh sang chung va anh sang cue bd tai nhUng vj tn cdng viec ddi hdi chinh xac. Thuc hien cac bien phap giam tie'ng dn trong MTLD nhu bao dudng may mdc thudng xuyen, tang khoang each giUa ngudn gay dn va NLD....
Tai lieu tliam khao
1. Hoang Khai Lap (2004), Khao siit DKLD nghien cUu dac diem sinh the tinh trang sUc khoe NLD danh gi^
viec thuc hien cac qui dinh ve BHLD a nganh ca khi luyen kim xet dudi gdc do yeu cau cOa quci trinh CNH va HDH dat nude, Bito Ccio ket qua nghien cUu 6e tai nhanh cap nha nude.
2. Nguyen Thi Thu, Nguyen Thi Bich Lien, Nguyen Thu Anh, VQ Minh Phuang (2003), "Khao sit DKLD va tinh hinh sUc khoe ciia NLD lang nghe Dai Bai-Bac Ninh", Hoi nghl khoa hgc Quoc te Y hoc tao ddng va Ve sinh mdi truang lan thU I.
3. Nguydn Thi Hong Tii (2000), Anh huang mdt so nguy ca nghe nghiep trong cac doanh nghiep nho va vUa den sUc khoe NLD, Luan an Tien sly hoc. Ha Ndi.
4. Nguyen Thi Toan (2002), Dieu tra ca ban thuc trang sUc khoe cdng nhan ca khi luyen kim, Bao do de tai nghien cUu khoa hgc cap bo. Ha Ndi-2002.
5. Sofoluwe-G. 0 (1968), Smoke pollution in duellung ofimfants broncho pneumonia. Archiwers of Environment and Health 1968 (P 670).
6. Vassileva lodorova L, DiptchikovS(1990), Effects of intence noise and of the micromate of various enery levels upon certein cardiovascular and thermoregulary parameters. Occup. Health and industrial media. Vol. 22,
USA, 1990, pi 5.U
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