III. PHAN THAO LUAN KET QUA NGHIEN CUTJ
Hai thdn Cau Dien va Hdng Phii deu bid nhilm HCTS tram trong Thdn Cau Diin d nhilm do HCTS ebon dUdi dat Do dao bdi, do
mua lu, HCTS da di vao dat, nUde, thiic vat. Su xam nhap nay cung gidng nhu cac con dUdng xam nhap HCTS ma Dao Ngoc Phong [33], H.O Brien [98] da trinh bay. Bui va hdi HCTS tit nha may san xuat HCTS Hoa Khanh da lam d nhiem thdn Hdng Phii la do gid va mUa dUa sang. Cach gay d nhiem nay ciing gid'ng nhU each xam nhap HCTS
tit cac vimg phun va sU dung HCTS deii cac vimg khdng sii dung HCTS. De giai quyet tinh trang dd, chiing tdi phai de nghi di dan di
ndi khac. Bien phap nay nhien nu()c da thitc hien. Theo Marion va Moses M.D, n a m 1987 d Cahfornia co 3 dc)t ch dan Kin do HCTS : 2 ddt
do guthion dUdc sU dung d nhUng viing trdng (tao va 1 d(jt do xa khi metylbromua tit canh ddng trdng hoa lay dn [97].
'-' Tdn lUciiig HCTS trong dat.
Tdn Imjiig DDT, HCH, wofatox trong dat tai thdn Cau Dien tUdng ditdng vdi tdn lUdng HCTS tai cac vung trdng cay cdng nghiep ciia Diic, Canada, My [33]. Tdn litcing DDT trong dat d tlum Cau Dien it n h a t la 3,5 mg/kg va cao n h a t la 22mg/kg. Ket qua nay gi(mg ket qua nghien ciiu tai cac vimg trdng cay ndng nghiep va cdng nghiep cua My (4,6mg/kg), tai vimg trdng cay ndng nghiep va cdng nghiep ciia Canada (17,Img/kg). Tdn lUdng ciia HCH, DDT, malathion trong dat tai thdn Hdng Phii cao n h a t la 4 mg/kg, gan bang tdn lUcing HCTS trong dat trdng r a u cua C a n a d a [15].
Cac mku dat tai cac diem d gan kho HCBVTV ciing cd tdn lUcing
HCTS cao gan mite tdn lUdng HCTS trong cac viing trdng rau (bang 14, 17).
'•'' Tdn lUdng HCTS trong nUdc.
Trong 120 m a u nUdc sinh boat va nxidc tudi r a u d thdn Can Dien,
Hdng Phii, n h a dng Thanh, HTX trdng nho, xung (luanh cac kho
HCBVTV cd 36.6% sd m a n (lua TCCP. Tai thdn Hdng Phii, tdn iMijng
DDT cao n h a t la 6,5mg/l, tdn ludng HCH la 8, lmg/1 (mU(mg nha ba Sanh); tdn lUdng wofatox la 5,2mg/l va malatlii(m la 3,4mg/l (nUdc
gieng n h a ba Md). Ket qua nay cung gid'ng ket qua nghien ciiu tdn lUdng HCTS tai mien J a v a cua Indonesia. Theo Foo Gai Sim, tat ca cac
nguon nudc ngot dxiOc kiem tra d mien Tay J a v a deu cd tdn lUdng
HCTS tii 0,1- 6mg/l cua 4 help chat trii sau cd photpho va cacbamat [84].
Ton lUdng HCTS trong nUdc sinh boat tai HTX trdng nho : chi cd 20% so'mau cd tdn lUdng qua TCCP. Tdn lUdng DDT tii 0,01 - 0,18mg/l
va wofatox tU 0,002 - 0,64mg/l.Ke't qua nay gidng ket qua nghien ciiu
nudc ciia 11 con sdng d My (ton lUdng DDT tdf hang t r a m den hang ngan microgam/lit) [33].
Tdn lUdng HCTS trong nUdc sinh boat tai cac n h a dan d gan kho HCBVTV ciing cao. Ton lUdng HCTS tai cac nha dan d xung quanh kho HCBVTV cao la do gid, mUa dua HCTS sang. Mat khac HCTS t h a m n h a p cac nguon nUdc cdn do nhiing ngUdi tiep xiic rUa chan tay, tkm giat quan ao d m h HCTS tai gieng. Theo Mary H.O.Brien, HCTS cd the di xa h a n g van dam. Hdi HCTS trong khi quyen gap mUa se dUa vao ngudn nUdc n g a m [98]. Vi vay, nhiing nha dan d quanh kho, xen ke •giUa ruong dong, trong nUdc gieng cd HCTS la dieu t a t nhien.
* O nhiem khdng khi
- Khdng k h i n h a dng Thanh bi d n h i l m t r a m trong, anh hudng den site khoe ngUdi tiep xiic (bang 21). Nha dng T h a n h d each kho HCBVTV 5 m nen khdng khi bi d n h i l m d miic khdng the chap nhan
3
dU(?c. Tdn lUdng DDT tai phdng ngu va tai gieng la 0,2 mg/m ., tai bep 3
la 0,15mg/m . Tdn lUdng HCH tai 3 vi tri tren cao gap tU 3-4 lan
HCTS cao gap 5 lan TCCP, tai gieng cao gap 6,5 lan, tai bep cao gap 5,2 lan (bang 21). Vi vay chiing tdi da de nghi chuyen kho HCBVTV
ciia Cdng ty vat tU xa Dien Lac di ndi khac. De nghi nay da dM6c giai
quyet.
- Trong 144 m a u khdng khi do tai cac kho, each kho 3-5m, tai chd pha che, each chd pha che 1-2 m, tai chd phun tren ruong liia, ruong bdng va tai n h a dan each cho phun 4-5m, cd 55,5% sd mku qua TCCP (bang 13).
- Ton lUdng HCTS trong khdng khi d gan cae kho HCBVTV (tii 3-
5 m), each chd p h a che, each chd phun thudc tU 4-5 m khdng cao (bang
2). Ton lUdng DDT trong khdng khi tai cac nha dan d lan can viing tiep xiic la 0,06 - 0,31 mg/ml. Trong nUdc ta chUa cd tac gia nao nghien ciiu ton lUcing HCTS d viing dan cU .
- Khdng khi thdn Hdng Phii bi d nhiem n a n g do bui va hdi HCTS
tit n h a may boa chat Hoa K h a n h dUa sang. Ndng do bui chiia 6% HCH
trong khdng khi tit 20-600 hat/cm2. Bui bam tren la di, la bUdi chiia l,5mg/kg DDT, 2,7mg/kg HCH. Khdng khi bi d nhiem nen dan den ngudn nUde ciing bi d nhiem (bang 20).
* HCBVTV trong thiic vat
Khdng khi, dat, nUde tai cac viuig nghien ciiu bi d nhiem nen thUe vat ciing chiia mot lUdng Idn HCBVTV (tii bang 14-32). Do sU di chuyen cua HCTS trong mdi trudng nen cd sU hen quan giiia tdn lUdng HCTS trong dat, nudc, thUe vat trong cung mot dia diem nghien ciiu. Ton lUdng DDT trong dat trdng khoai mdn la 22,0 mg/kg, thi tdn lUdng DDT trong khoai mdn la 4,6mg/kg; ton lUdng DDT trong dat trdng khoai mi la 20,2 mg/kg
thi tdn htdng DDT trong khoai mdn la 4,6mg/kg ; tdn lucing DDT trong dat trdng khoai mi la 20,2 mg/kg thi tdn lUcing DDT trong khoai mi la 5,5mg/kg (bang 32). Tdn litcing wofatox trong dat trdng khoai lang la 14,5mg/kg tlii trong khoai lang la 3,0mg/kg <bang 32). Tdn lUdng HCH trong dat trdng khoai mdn la 2,8mg thi trong khoai mdn la 0,42mg/kg (bang 14 v a 3 2 ) .
Khi tdn lUcing wofatox trong nUdc tai nha ba Md la 5,2mgA (bang
32) thi tdn l\i6ng wofatox trong khoai mi la 4.0mg/kg; Tdn lUdng DDT
trong nude n h a ba Sanh la 6,5mg/l thi trong khoai mdn la l,5mg/kg; tdn lucing HCH trong nUdc nha dng NhU la l,Omg/l thi trong thdm (diia) la 0,05mg/kg. Dieu nay da ndi len rkng HCTS da (h chuyen va phan bd lai giUa cac ddn vi trong mdi trUdng [60,78].
'-^' Tdn lUdiig DDT trong ddng vat.
Trong 30 m a u md ga, md Icin d P h a n Rang va Nha Trang deu cd p,p'-DDT. Mau md ga cd tdn lUcing p,p'-DDT cao n h a t la l,5mg/kg va thap n h a t la 0,9mg/kg. Mau md Idn cd tdn lUdng p,p-DDT cao nhat la l,8mg/kg va t h a p n h a t la 1, Img/kg (bang 38)
=^ O nhiem HCTS do bao lut.
Tinh t r a n g d nhiem mdi trUdng quanh kho HCBVTV Ddng Tac sau t r a n bao, lut ngay 2/10/1993 la mot dien hinh. Day la tinh trang chung cua cac kho HCBVTV d mien Trung sau nhiing tran bao lut Idn. NhUng cho den nay ciing chUa cd tac gia nao tdng ket de riit ra kinh nghiem trong cdng tac phdng chdng d nhiem mdi trUdng. Sau tran bao lut dd, 2.800kg HCH bi Udt hoan toan, t a t ca cac thiing chiia 2,4D, wofatox, monitor deu trdi bdng benh trong nudc. Do dd cac m a u nudc gieng d xa 250m, 500m, 60()m deu cd wofatox; 2,4-D va HCH. Nudc bi d
nhiem nen dat va thitc vat cung cd tdn lUdng HCTS Idn qua TCCP. Sau 1 t h a n g tdn lUdng HCTS cd giam so vdi lan dau nhung van cao qua TCCP (bang 24). Sau 2 t h a n g tdn htdng HCTS trong thitc pham cung cdn cao (bang 35).
Nudc can cho sinh boat ciia con ngudi hang ngay, hang gid, nUdc bi d nhiem HCTS da anh hUdng nghiem trong den siic khoe ciia nhan dan (ngiia da, dau bung do an udng va tkm rUa...). Do dd chiing tdi da nghien ciiu phitong phap xii ly HCTS trong nitdc bi d nhiem.
3.4. Xii ly HCTS trong nUdc.
Chiing tdi da nghien ciiu dimg K M n 0 4 d cac ndng do khac nhau de loai HCTS trong nUdc. K M n 0 4 cd the loai dUdc HCTS trong nUdc nhUng ban t h a n K M n 0 4 neu cdn thita trong nUde se gay ddc khi udng. Neu dung K M n 0 4 de loai HCTS trong nUdc thi nUde cd mui r a t tanh, khd udng. Chiing tdi da nghien ciiu dimg cac loai than de loai HCTS trong nUdc. Neu t h a n boat tinh dat tien, cd the dung than so dita hoac than cui de loai HCTS (bang 40). Than so dita va t h a n cui cd rat nhieu d mien Trung. Hai loai t h a n nay rat d l tim, gia t h a n h re, moi nha deu CO the m u a de loai HCTS trong nitdc sinh boat. Dung cu de loai HCTS trong nUdc ciing dem gian, d l lam, re tien (hinh 9). Loai HCTS bkng than boat ai ciing biet nhUng de ra t h a n h mot bien phap de ap dung thi chua cd tac gia nao de cap den. Chiing tdi da t h a n h cdng trong viec hudng dan n h a n dan dimg t h a n so dita hay t h a n cui de loai HCTS trong nudc sinh boat tai cac dia diem bi d nhiem nang (nhat la cac viing sau bao hit).
3.5. HCBVTV a n h hudng den site khoe ngU(ri tiep xiic.
'•'' Lam d u n g HCBVTV.
Trong nhUng n a m 1981-1983 d mien Nam mot so tu thUdng da lam dung warfarin - mot chat dimg d l chet chuot cho vao phan rdm tre em. Ho lam tUdng warfarin la mot chat dinh hUdng. Dieu dd da dem lai tac hai nghiem trong cho tre em dUdi 5 tudi n h a t la 1-2 thang tuoi. Mot vu dich xuat huyet da tr(^ em do dung phan rdm da xay ra va keo dai trong nhitng t h a n g cudi n a m 1981 va dau nam 1982. Chiing tdi da kiem t r a 290 hop p h a n rdm ban tren thi trudng va do cac benh vien d Nha t r a n g chuyen den. Trong sd do cd 204 hop phan chiia warfarin, chiem 70,3%. Nhiing h()p pban cd warfarin bi giU lai khdng ctucic dung, do dd da ngan chan dude dich xuat huyet da. Su kiem soat nay cho den nay van dUcic duy tri. Ket qua nghien cuu ciia chiing tdi phu hop vdi ket qua ciia cac bac si d benh vien Nhi ddng thanh phd Hd chi Minh [70].
'•' Anh hudng den site khoe ngUdi tiep xiic mdi trUdng.
Do HCTS tdn tai trong khdng khi, dat, nude, thUc vat nen anh hudng den siic khoe ciia n h a n dan thdn Cau Dien va thdn Hdng Phii. Tai thdn Cau Dien chi cd 497 ngUdi ma trong may n a m da cd 2 ngUdi bi chet do nhiem doc, 6 ngiidi bi rung tdc, 4 ngUdi bi benh tam than, 7 ngudi bi de non, 4 ngUdi say thai va sinh thai di dang (muc 2.5.3).
Kiem tra 31 ngUdi d thdn Hdng phii thi chi cd 2 ngUdi cd boat tinh enzym cholinesteraza d miic binh thUcing (bang 43). Tinh trang siic khoe cua n h a n dan 2 thdn tren bi de doa nghiem trong la do tdn lucing HCTS trong (tat, nudc, thuc vat qua cao va cluing dU()c ton tai lau dai.