Nghiên cứu phân tích, đánh giá tồn lượng hoá chất bảo vệ thực vật và tình trạng ô nhiễm môi trường ở một số tỉnh miền Trung : Luận án PTS. Hóa học: 62 44 27 01

BO GIAO DUG VA DAO TAO
TRirdNG Dm HOC T6NG HOP HA Ndl
Phung Thi Thanli Tu

NGHIEN CtrtJ PIIAN TICH, DANH GIA
TON LlTdNG HOA CHAT BAO VE THlTC VAT
VA TINH TRANG 6 NHIEM MOI TRlTdNG
6 MOT SO TINH MIEN TRUNG
Chuyen nganh :
Ma so

Hoa hCru ccf
01.04.02

LUAN AN PHO TIFN SI KHOA HOC HOA HOC

Ngudi htfdng d d n khoo hoc :
GS. TS
PGS.PTS

HANOI. 1994

: NGO THI THUAN
: N G U Y I N D Q C HUE


MUG LUC
Trang
DAT VAN DE
I. Phan tong quan tai lieu

1
3

1.1. Khai niem chimg ve HCBVTV

3

1.2. Phan loai HCBVTV

3

1.3. Tmh hinh san xuat va sik dung HCBVTV

5

1.4. Tac hai cua HCBVTV

7

1.5. Ton lifdng HCBVTV trong moi tnl6ng

24

1.5.1. Su di chuyen cua HCBVTV trong moi trifdng

24

1.5.2. Van de ton lifdug HCBVTV trong nong san

28

1.5.3. Phildng phap phan tich ton lUdng HCBVTV
trong moi trildng
n. Phan thilc nghiem

29
39

2.1. Lap doing phudng SKLM de xac dinh ton lUdng HCTS

39

2.1.1. Thiet bi, dung cu, hoa chat

39

2.1.2. Lap dung phiidng phap phan tich

40

2.1.3. Do thu hoi cua ton liidng HCTS trong cac doi tildng

52

2.1 A. Cach tinh ket qua

53

2.2. Lap dung phiidng phap xac dinh warfarin trong phan rom

54

2.2.1. Thiet bi, dung cu, hoa chat

55

2.2.2. PhUdng phap sinh hoc

55

2.2.3. Phiidng phap phan tich hoa hoc.

57

2.3. Lap dung phUdng phap GC/ECD xac dinh HCTS.

62


. 2.3.1. Thiet bi, dung cu, hoa chat

62

2.3.2. Phiidng phap phan tich

62

2.4. LTng dung

65

2.4.1. Doi tUdng nghien ciiu

66

2.4.2. Nghien ciJu tinh trang 6 nhiem moi tru5ng

67

2.4.3. Ton liidng HCTS bi cam sik dung va han che sik dung

79

2.4.4. Ket qua xac dinh ton lUdng HCTS bkng phUdng phap
GC/ECD

86

2.4.5. Ton liidng HCTS trong liidng thiic

87

2.4.6. Ton lUdng DDT tren dong vat

88

2.4.7. Su lam dung HCBVTV

88

2.4.8. Xii ly HCTS trong nvfdc

89

2.4.9. Tac tai cua HCBVTV den sufc khoe ngUcii tiep xuc

90

ni. Phan thao luan ket qua nghien ciiu

95

3.1. PhUdng phap phan tich.

95

3.2. Ton lUdng HCTS bi cam va han che sU dung d mien Trxmg

102

3.3. Danh gia mtic do 6 nhiem moi trudng d mien Trung

106

3.4. Xik ly HCTS trong nUdc

111

3.5. HCBVTV anh hu6ng den siic khoe cua ngUdi tiep xuc.

112

IV. Phan ket luan

Tai lieu tham khao
Phu luc

115


DAT VAN DE
Hien nay tren the gidi, hoa chat bao ve thUc vat (HCBVTV) ngay
cang dUdc dung rong rai trong nong nghiep de bao ve cay trong va bao
dam cung cap lUdng thUc, thUc pham nuoi song con ngUcJi [ 1, 23]. Theo
To chiic Y te the gidi (TTYTTG), hang nam cac loai con trung va sau bo
pha hoai khoang 33 trieu tan lUdng thUc. So' lUdng nay c6 the nuoi
song 150 trieu nguM trong mot nam [ 38, 53 ]. 6 nU6c ta HCBVTV
dUdc diing rong rai. Hang nam lUdng HCBVTV svL dung binh quan la
0,5 - 0,7 kg hoat chat / ha [24]. Nhd diet dUdc con trung sau benh nen
san lUdng lua tang 10%,b6ng, day, do tUdng, cam, che tang tii 17,6 - 70
% [ 5, 53 ]. Nam mUdi nam qua, viec dung HCBVTV mot each than
trong va c6 kiem soat la dieu can thiet de phat trien nen nong nghiep
hien dai va sit dung trong viec khong che cac benh do con trung truyen
[12, 19] va vi vay Idi ich cua HCBVTV da vUdt xa so v6i gia thanh
cua no [ 10,34 ]. Tuy nhien neu HCBVTV dUdc dung khong dung
each hoac khong than trong se de doa nghiem trong den stic khoe con
ngUdi, den nong nghiep va he sinh thai noi chung [ 27.34 ]. Hang nam
ty le nhiem doc va t i vong do hoa chat trit sau (HCTS) kha 16n [56,58].
Nhieu loai HCBVTV c6 kha nang ton lUu lau dai d moi trUdng, gay 6
nhiem dat, nU6c, khong khi, tac hai lau dai den siic khoe va Ian truyen

tii the he nay sang the he khac [76, 81 ]. Hien nay sU quan ly
HCBVTV d nUdc ta chUa that chat che. O mien Trung, dat dai can coi,
sau benh luon de doa mua mang. Dae trUng cua khi hau mien Trung
la : nhiet do cao, lUdng mUa Idn va gio bao nhieu. Dieu do de dang cho
viec di dong nhanh cac ton lUdng HCBVTV vao khong khi, dat, nU6c,
gay 6 nhiem moi trU5ng tren mot dien rong. Mac du nha nU6c da c6


lenh cam dung diclodiphenyl tricloetan (DDT), hexacioxiclohexan
(HCH) va han che sU dung wofatox, monitor [75] nhUng cho den nay
nhan dan van quen dung wofatox va monitor. Su quan ly HCBVTV d
mien Trung cung con long leo. Do do viec nghien ciiu phan tich, danh
gia ton lUdng HCBVTV va tinh trang 6 nhiem moi trUc^ng d mien
Trung la dieu can thiet va c6 y nghia.
Chung toi tien hanh nghien ciiu de tai nay n h a m muc dich :
- Lap dilng phUdng phap phan tich s^c ki 16p mong (SKLM), sac
ki khi detectd cong ket dien tii (GC/ECD) va phUdng phap do quang
thich hdp de lam phUdng tien khao sat ton lUdng HCBVTV trong moi
trUcfng.
- Danh gia ton lUdng hoa chat tri^ sau bi cam sii dung va han che
sii dung ci mot so' tinh mien Trung.
- Danh gia tinh trang 6 nhiem moi trU6ng do HCBVTV gay ra tai
cac cd scl san xuat, bao quan, sU dung va sau cac ddt bao lut d mien
Trung.
- De xuat mot so' bien phap giai quyet tinh t r a n g 6 nhiem moi
trudng.


I. PHAN TONG QUAN TAI LIEU

1.1. Khai niem chung ve HCBVTV
HCBVTV la ten goi chung de chi cac hoa chat dung trong nong
nghiep, lam nghiep, nh^m muc dich diet sau benh, c6 dai, con trung va
dong vat gam nham de bao ve cay trong, cac Idio lUdng thUc hang hoa
... [41, 61].
1.2. Phan loai

HCBVTV

1.2.1. Phan loai theo muc dich sit dung [21, 61]
* Nhom cac chat tru! sau, trii nhen, t r i con trung gay hai :
- Cac chat trtT sau nhom cd clo : DDT, HCH, endrin diendrin,
clodan
- Cac chat trtf sau nhom cd photpho : wofatox,

diazinon,

malathion, monitor...
- Cac hdp chat cacbamat: sevin, furadan, mipcin, bassa...
- Cac hdp chat sinh hoc : piretroit, permetrin, dentametrin.
* Nhom cac chat trii nam, trii benh, trii vi sinh vat gay hai :
- Cac hdp chat chiia dong
- Cac hdp chat chiia lUu huynh
- Cac hdp chat chiia thuy ngan
- Mot so'loai khac
* Nhom cac chat trii c6 dai, lam rung la, kich thich sinh trUdng :
- Cac hdp chat cua phenol
- Cac hdp chat ciia phenoxi [2,4 diciophenoxyaxetic axit -2,4 - D]
- Cac dan xuat cua axit alofic [dalapon]
- Cac dan xuat cua cacbamat [satxm, eptam]]

- Triazin [simazin, atrazin, evik...]


* Nhom cac chat diet chuot va dong vat gam n h a m : phoszin va
warfarin
1.2.2. Pban loai tbeo nguon goe san xuat va eau true boa boe
1.2.2.1. HCBVTVhvtu

ca[41, 83]

- Cac chat BVTV nhom cd photpho : metyl parathion [114],
parathion [117] monocrotophot [119], diazinon [122], malathion [128],
dimetoat [142], azodrin [143].
- Cac chat BVTV nhom cd clo : DDT [89] andrin [118], HCH [125,
147], cloran [137], heptaclo [141], 2,4-D[123, 139].
- Cac chat trii sau thuy ngan hUu cd,ceresau, granosan, felizan [114]
- Cac dan xuat cua hdp chat nitro

[41]

- Cac dan xuat ciia ure

[41]

- Cac dan xuat ciia axit cacbamic

[61]

- Cac dan xuat cua axit propionic

[41]

- Cac dan xuat cua axit xianhidric

[41]

1.2.2.2. Cac chat trvtsau v6 ca:

[41, 61]

- Cac hdp chat ciia asen

[131]

- Cac hdp chat ciia dong

[61]

- Cac hdp chat cua lUu huynh

[138]

- Cac hdp chat v6 cd khac

[114]

1.2.2.3. Cac chat trii sau nguon gob thiic vat la : cac ancaloit,
thUc vat CO chiia nicotin, anabazin, piretroit [41, 121, 140]

1.2.3. Pban loainbom

doe tbeo TCYTTG [131, 132]


Bang 1 : Phan loai nhom doc theo TCYTTG
(LD50 mg/kg, chuot nha)
Phan nhom doc

la. Doc manh
lb. Doc
II. Doc trung binh
III. Doc it
IV.

Qua
mieng
The ran
5
5-50
50 - 500
500-2000
>2000

Qua da
The long
20
20 - 200
200 - 2000
2000-3000
>3000

The ran
10
10 - 100
100 1000
1000

The long
40
40-400
400-4000
4000

1.3. Tinh hinh san xuat va sik dung HCBVTV :
L3.1. Tlnb binb sin xuat va svt dung HCBVTV

tren

tbegioi

Tii lau con ngUdi da biet dtmg mot so' san p h a m tU nhien de diet
truf sau benh nhu cac hdp chat cua asen, cac hdp chat ciia flo, cac chat
CO nguon go'c thUc vat va dau khoang [1, 61]. Tii n a m 1849 - 1922 cac
san p h a m xong Idioi cua cac chat v6 cd va dau hoa cung dUdc diing de
diet trii sau bo [38]. Tii sau n a m l 9 2 3 , cac hdp chat trtt sau tong hdp ra
ddi [41]. Nhom HCTS dUdc diing sdm n h a t la DDT, HCH. Tiep theo la
cac hdp chat endrin, diendrin. Cac hdp chat cd clo nay ton tai qua lau
trong moi trUdng va tich luy trong cd the dong vat, gay hai cho moi
trUdng va con ngudi. Do do ngay nay nhieu nu6c da cam diing [36, 89,
90]. Nhom HCBVTV tong hdp phong phii va dUdc sU dung rong rai

nhat trong nong nghiep la nhom HCTS cd phot pho va cacbamat [61,
94].
Ngay nay cac nU6c tren the gidi dang khuyen khich dung cac
phUdng phap sinh hoc va cac phUdng phap phong trii tong hdp de bao
ve thUc vat, n h a m h a n che sU dung HCBVTV c6 hai cho moi trUdng.


Tuy vay, hien nay HCBVTV van dUdc sii dung vdi khoi lUdng 16n tren
the gidi. U*6c tinh hang nam cac nU6c tren the gidi diing khoang 1,25
ti

tan nguyen chat HCBVTV [23]. Hien nay cd khoang 100.000 hdp

chat hoa hoc dUdc tong hdp va dUdc thi nghiem de lam HCBVTV [38].
Trong dd cd khoang 1.500 hdp chat dUdc xac dinh tinh nang, 500 hdp
chat dat tieu chuan quoc te, dUdc dua vao sii dung [56]. Rieng d My
cdl.200 HCTS da dUdc dang ky, 35.000 san pham thUdng mai dUdc ban
dudi dang cac thUdng pham khac nhau [5]. Tuy cd nhUng y kien khac
nhau ve viec sii dung HCBVTV nhUng miic sU dung HCBVTV hang
nam tren the gidi van tang tren 10% [53]N a m 1985 My sU dung 486 trieu tan HCBVTV, rieng nganh
nong nghiep sU dung 464,22 trieu tan [38]. Indonexia n a m 1982 sii
dung 45.258 tan bao gdm 450 loai HCBVTV, chi phi cho HCBVTV phat
trien manh, ty le tang trung binh hang nam la 15-20% [84]. Malaixia
trong n a m 1983 ban hdn 100 trieu do la My, trong dd thudc diet c6
chiem 80%, thudc diet con trung chiem 12% [84]. Nam 1981 Thai Lan
sii dung khoang 35.000 tan HCBVTV, tri gia 130 trieu dd la My [84].
Tanzania cud'i n a m 1981, cdng ngliiep ca phe diing khoang 6353 tan
HCBVTV [50, 71]. Columbia trong n a m 1985 xuat k h a u 6693 tan
HCBVTV vdi tri gia 490.969 dd la My [82]
O cac nUdc phat trien, HCBVTV dUdc quan ly chat che tit khau

san xuat, dang ky xuat khau, bao quan, van chuyen, sii dung; cd nhieu
trung t a m nghien ciiu sU ton lUu ciia HCBVTV trong moi trUdng va tac
hai cua chiing doi vdi con ngUdi [24, 50].


1.3.2. Tinh binb sin xuat vasvt dung HCBVTV d Viet Nam
Tii xa xUa, nhan dan ta da biet dung nicotin lay tii cay thudc la,
thudc lao va rotenon che tU mot sd' cay ho dau de trii sau hai rau va
cay an qua. N h a n dan Nam bo da diing dau gasol de phong trii ray nau
hai Ilia d cac tinh mien Tay. Tii n a m 1957, DDT va nhUng hdp chat
tUdng tu dUdc diing rong rai d nUdc ta [41]. Tii n a m 1963 d mien B^c
da diing nhieu wofatox, dipterex, malathion, Bi58 [61]. O mien Nam
n h a n dan diing nhieu diazinon , monitor, orthene, azodrin [41]. Nudc
ta la mot nUdc ndng nghiep, khoang 13 trieu ho gia dinh gom 52 trieu
ngUdi lam viec trong linh vUc ndng nghiep [18, 43], do dd viec sii dung
HCBVTV ngay cang tang [51, 57]. Trong tong so HCBVTV dUdc sii
dung, HCTS chiem 68%, HCTN chiem 24% va HCTC chiem 8% [43].
LUdng HCBVTV diing binh quan hang n a m la 0,5 - 0,7 kg hoat chat/ha
[57]. Trong Idii dd d Nhat la 14,05 kg hoat chat/ha, d Balan la 0,94 kg
hoat chat/ha, d Hungari la 8,93 kg hoat chat/ha, d Thuy Dien la 4,93
kg hoat chat/ha, d My la 4,56 kg hoat chat /ha [38, 48].
HCBVTV dUdc sii dung d nUdc ta chu yeii tii nguon nhap khau.
Sd lUdng HCBVTV hang nam dUdc thong ke nhUng chua day du vi
hien nay cd nhieu ngudn nhap HCTS khong hdp phap. Theo so lieu
thong ke chUa day du : nhUng nam cua thap ky 80, hang n a m nude ta
nhap tii 8-9 nghin tan va nhUng n a m dau thap ky 90 nhap tii 20-24
nghin tan HCBVTV [38].

1.4. Tac hai cua HCBVTV.
1.4.1. Tinb hinh nbiem doc HCBVTV.

1.4.1.1. Tinh hinh nhiSm doc HCBVTV

tren the gidi.

So' ngUdi bi n h i l m doc HCBVTV ngay cang tang tren the gidi
[38]. N a m 1977, dUa vao bao cao cua 9 nUdc, TCYTTG [24] da Udc tinh


hang nam tren the gidi cd 20640 ngUdi chet vi HCBVTV. Nam 1981
TCYTTG Udc tinh rang toan cau cd 750000 ngUdi bi nhiem doc. Gan
day Uy ban Idnh te va xa hoi chau A va Thai Binh DUdng da cho biet
so' ngUdi bi nhiem doc len den 2 trieu, trong dd sd' tii vong la 40000
ngudi [24]. Theo Rosenstock

[36]

d

My

cd khoang 3000 cdng

nhan bi nhiem doc hang nam. Nam 1987 cac tac gia dieu tra tai phong
kham cap ciiu va nhap vien d Nebraska thay ty le nhiem doc HCBVTV
la 1,35/1000 dan, trong dd nhilm doc HCTS nhom cd photpho chiem
25% [50]. d Indonexia tii 1974-1982 cd it nhat 1065 ngUdi bi nhiem doc
HCBVTV, trong dd cd 54 ngudi chet. Rieng mien dong Java nam 1980
cd 431 ngudi bi nhiem doc trong dd cd 17 ngUdi chet. Thii do Giacata
trong mot nam cd 165 ngUdi bi nhiem doc chiem ty le 1,99% trong tong
sd' benh nhan nhap vien [84]. 6 Malaixia tii nam 1977-1981 cd 569

ngUdi bi chet, chii yeii la do paraquat, malathion va DDT. Tii thang
1/1981-6/1982 ti le nhigm doc paraquat la 46/100000 dan. Ti le chet do
paraquat 54,5% [84]. O Srilanca tii nam 1975-1980 hang nam cd
khoang 13000 ngUdi bi nhigm doc HCBVTV, cd khoang 1000 ngUdi
chet [84]. U Thai Lan Udc tinh hang nam cd it nhat 1000 ngUdi bi
nhidm doc HCBVTV, khoang 100 ngUdi tii vong [84]. Theo Bary [76] va
Fest [83] khoang 10% cac trUdng hdp bi nhiem doc cap ciiu la do
HCBVTV, trong dd cd 50% la do nhdm cd photpho.
1.41.2 Tinh hinh nhiSm doc HCBVTVd Viet Nam
- Theo Le Dinh Cdng, ci Ben Tre tU nam 1986-1992 cd 1102 ngUdi
bi nhiem doc, cd 208 ngUdi chet [5]. 6 Tien Giang tii nam 1986-1992 cd
3.167 ngudi bi nhigm doc HCBVTV, trong dd cd 333 ngUdi chet [60].

8


Theo Le Trung, tu: n a m 1986-1991 sd ngUdi vao dieu tri d mot so benh
vien tinh t h a n h va benh vien Bach Mai la 3.019 ngUdi, trong dd sd'
ngitdi tu tu cliie'm 89,5%, do nham l i n la 3,8% va do nghe nghiep la
6,6%. Ty le tii vong do nhiem doc HCBVTV kha cao, trong dd HCTS cd
photpho chiem 10,4% [58].
1.4.2. Tac hai chung cua HCBVTV.
HCBVTV it hay nhieu deu doc vdi cd the con ngUdi, gia cam, gia
siic va moi trUdng song [12, 56, 76]. Mile do nhiem doc phu thudc vao
titng loai HCBVTV, lieu lUdng, dudng xam nhap vao cd the va cd dia
cua tiing ngUdi tiep xiic [51, 92, 102].
Ngitdi ta thUdng bi t h a m nliiem HCBVTV qua 2 phUdng thiic :
tiep xiic nghe nghiep va tiep xiic mdi trUdng. Tiep xuc nghe nghiep,
dudng xam nhap chii yeu qua da va dudng ho hap. NgUdc lai, tiep xiic
mdi trUdng chii yeu qua dUdng tieu hoa (vdi thiic an, nUdc udng bi

nhiem HCBVTV) [76, 78].
Mdi loai, mdi nhdm HCBVTV cd cd che tac hai Ichac n h a u . Cd
the tong quat cd che chung d hinh 1 va 2 [5]
^

Khong khi
''

Dat

^'
-

*

1

Sinh thai

s^

^

'

Nude

Ngudi

tl lUc a n

Hinh 1 : Su lUu chuyen ciia HCBVTV trong mdi trUdng


Hau qua khac

Nhiem doc

.t

I

1

1

r

V

i

Cap

Ban

Man

Di

Di

Sinh

Mang

tinh

cap

tinh

truyen

tog

bao

HCBVTV

non

tinh
^

•

V

>•

Doc

Doc

Dot

bao

sinh

bien

thai

hoc

gien

Hinh 2 : Tac hai cua HCBVTV

i . 4.3. Tac hai cua HCTS nhom cd clo.
HCTS nhdm cd clo la dan xuat clo ciia cac hidrocacbon da nhan,
cac xicloparafin cac tecpen va benzen : cacbon tetraclorua, DDT, HCH,
cloperin, pentaclonitrobenzen... Cac chat nay cd clo trong phan tii nen
nen tac dung ciia chiing dd'i vdi cd the nhieu liic gid'ng nhau, chi khac
ve miic do doc tinh va bieu hien lam sang [31, 76, 78]. Dae tinh chung
ciia cac loai HCTS cd clo la ben vUng d mdi trUdng ben ngoai, tac dung
m a n h vdi n h i e u loai con triing gay hai, cd tinh tich luy rd ret va cd
k h a n a n g gay n h i e m doc cap tinh va man tinh cho ngUdi [15,42].

C h a t doc gay ton thUdng nhieu cd quan va he thong khac n h a u ,
nhUng chu yeu la tac dong len he t h a n kinh, gan, t h a n , he thdng
t i m mach va m a u [54, 81]. Cd che tac dung doc cua HCTS cd clo

10


chua dUdc kh^ng dinh [38, 41]. Nhieu nghien ciiu cho thay cac chat
nay gay rdi loan cac he thdng enzim quan trong, do dd lam thay doi cac
qua trinh chuyen hoa, tang tinh trang thieu oxi d cac to chiic [76, 90,
104]. HCTS-cd clo cd the xam nhap vao cd the qua dUdng ho hap, tieu
hoa, da [53, 541. Klii chat doc xam nhap vao cd the dii lUdng nhd cung
gay nhiem doc man tinh vi nd tich luy trong cd the, dac biet la d to
chiic md [ 92, 104]. Da sd' HCTS - cd clo deu dao thai qua sUa va gay
doc dd'i vdi noi gid'ng [36, 118, 109]. Cac hdp chat DDT, diendrin,
andrin ... cd thdi gian ban huy sinh hoc dai [22, 28]. Chiing phai dUdc
xii ly nghiem ngat vi chiing hen quan den mat can hkng sinh thai va
anh hudng t r a m trong den siic khoe con ngUdi [102, 103]. Tat ca cac
chat nay deu dUdc chiing minh la cac chat gay ung thU tren dong vat
[36, 137, 139, 144, 145, 147]
1.4.4. Gidi tliieu mot so HCTS - ccf clo tbiidng dung
1.4.4.1. DDT, Ci4HgCl5, M=345,5[131

144]

- DDT cd ten la diclo diphenyl tricloetan. Nd con cd ten khac :
azotox [41], gesarol [103], neoxit [144].

- DDT cd cdng thiic can tao :
H

^ ^ - Q - ^ - Q ^ '

* l,l,l-triclo-2,2 - bis (p-clophenyl)etan
*P,P-DDT

CClg

- DDT diet dUdc con triing rat hflu hieu, ducic tong hdp tif nam
1939 [38, 41]
- Co 2 loai dong phan o,p' - DDT va p, p' - DDT, nhUng loai c6 tac
dung keo dai va pho tac dung rong doi vdi con trung la p, p' - DDT [21]

11


- DDT cd dang tinh thd khong man, bay hdi d ap lUc 1,5.10'^
mmHg tai 20^C,ndng chaydl09^GDDT dd tan trong cac dung mdi hiiu
cd (hidrocacbon thdm va cac dan xuat halogen cua chiing, cac xeton,
cac este cua axit cacboxylic). DDT tan kem trong cac hidrocacbon mach
th^ng va vong no. 6 nhiet do 27^C DDT hoa tan trong nUdc vdi nong
do 0,001 mg/1 [38]. DDT ben vttng vdi tac dong cua nhiet do, dun sdi
vai gid van khdng bi phan huy. Trong mdi trUdng Idem bi phan huy
thanh DDE it doc hdn. O dieu kien tU nhien, tinh doc ciia DDT duy tri
d U d c l 2 n a m [ 4 1 , 144]
- DDT ky thuat, san pham thUdng mai, chiia khoang 70% dong
phan p, p' -DDT va mot lUdng nhd dong phan o,p' -DDT [38]. Trong
dieu kien tU nliien chi mot lUdng nhd DDT dUdc phan huy trong mdi
trUdng do chuyen hoa thanh cac san pham it hoat dong hdn nhU la
DDE, DDD, DMC, dicofol, clo benzylat, metoxiclo [81, 106].
a) DDE cd ten goi : 1,1 - diclo 2,2 - bis (p-clophenyDetUen

ci_(
>-^^A_/"^i
V /
CCl, ^ - ^
'•• D D E
Hang n a m sU phan huy DDT t h a n h DDE trong mdi trUdng chi
chiem vai phan t r a m [81, 103]
b) -DDD la mot chat ket tinh mau trang, ndng chay d 109^C, ben
trong mdi trUdng. Nd chi bien hoa cham t h a n h nhUng hdp chat it hoat
dong hdn [106].
^^~\^~^—

H

* Diclodiphenyl dicloetan

C^" ^^
CHCl2^—

* Tetraclodiphenyletan
* TDF
* Rotan

c) DMC la chat ket tinh cd mau, ndng chay d 70 ^C, DMC it ben
trong mdi trUdng hdn DDT va DDE [81, 106]

12


— ?^ —

CI— ^ / ) ~ ^ ^ — C y)~*^^
^ ^
CH3 ^ - ^
•

"^ 4,4'-cUclometyLbenzhidrol
^^ DCPC
^= Dimit

d) - Dicofol cung dUdc chuyen hoa tU DDT trong to chiic ciia cd
the con triing. Nd la mot chat long nhdt mau vang, tan nhieu trong
nude hdn DDT va it ben hdn DDT [106].
OH
* 4,4' diclo-triclometyl - benz hi drol
CI — <( )>-(!: — ^ )>— CA '•^'- Kentan
e) Clobenzylat cung la san pham phan huy ciia DDT. Nd khdng
doc vdi tat ca cac loai cdn triing, la chat ket tinh mau vang, ndng chay
d37OC[105]
*^^~'4 //~" ^-^""v y — ^'^
c
O^

* Etyl 4,4'-diclobenzylat

OCH2CH3

D San p h a m cudi ciing la metoxiclo. Metoxiclo it ben trong mdi
trUdng hdn DDT, nd chiu tac dung khii clo n h a n h hdn [106].
H
C H 3 0 - { ^ ^ H ( ^

CCI3

''l,l,l-triclo-2,2-bis(P-metoxiphenyl)etan
* DMDT
'-''• Metoxi - DDT

- DDT thudc nhdm doc loai II, LD50 : 113 mg/kg [131, 132] ADI :
0,02 mg/kg [131]. Nong do td'i da trong mdi trUdng lao dong la 1 mg/m^
trong khi quyen la 0_,05mg/m'^ [72].
- DDT ditdc dung de trii" cac loai cdn triing, sau hai khac nhau
vdi lieu 0,3 - 2 kg/ha (khdng tac hai len ve va chau chau). DDT tru sau
bap cai va mudi. Tac dung trif sau ciia DDT chu yeu la tac dong len he

13


than kinh. Nd bit cac Id tren mang te bao than kinh, ngan chan qua
trinh tham hiit Na+ va lam mat tinh phan cUc cua te bao than kinh
dan den khdng dan truyen dUdc xung lUdng. Vi vay DDT dUdc xem nhU
la mot trong cac HCTS quan trong nhat va dUdc sii dung rong rai
trong ndng nghiep [41]. Do sU ton lUu lau dai trong mdi trUdng nen
ngay nay DDT da bi cam diing [133]. Nudc ta van cdn mot sd ndi sii
dung DDT do cac nguon budn lau dUa vao. Ndng dan sii dung DDT
trong khau khii trung dat, bao quan hat gidng [24, 61].
- DDT tich luy trong to chiic md cua ngUdi va dong vat, luan
chuyen trong cac ddi tUdng tU nhien ciia mdi trUdng (dat, nUdc, khdng
khi, cay cd ...) Vi vay mac du da cam sU dung, ngUdi ta van tim thay
DDT va cac san pham chuyen hoa ciia nd trong cac cd quan phii tang
cua con ngudi va dong vat [101, 106], DDT va cac san pham chuyen

hoa cua nd dUdc thai qua stfa va nUdc tieu khoang 1% trong ngay. Khi
phan tich DDT d tre sd sinh nhan thay cd khoang 0,24 mg DDT trong 1
kg can nang ciia tre sd sinh do bii sUa me cd DDT [38]. Lieu chet dd'i
vdi ngudi theo dUdng tieu hoa la 20-30 g DDT d dang nguyen chat, neu
DDT d dang hoa tan trong dau thi chi can 14 g [38]. Theo Biii Thanh
Tam, neu udng n h a m thi lieu gay nhiem doc la 3-5 g D13T tinh khiet
[41].
1.4.4.2.2. HCH - Hexacioxiclohexan, CeHeClc, M = 290,8
- HCH cd ten goi : 1, 2, 3, 4, 5, 6 hexacioxiclohexan
- Cac ten khac : hexaclo, hexacloran, lindan, gamakan, 666 [124,
147]. H.Faraday tong hdp HCH ti^ nam 1925, Vander Linden tim ra
cac dang dong phan cua HCH va chiing dUdc dimg lam HCBVTV tii nam
1935. Cd 8 dong phan ciia HCH. NgUdi ta thUdng sit dung dong phan a

14


than kinh. Nd bit cac Id tren mang te bao than kinh, ngan chan qua
trinh tham hiit Na"*" va lam mat tinh phan cUc cua te bao than kinh
d^n den khdng dAn truyen dUdc xung lUdng. Vi vay DDT dUdc xem nhu
la mot trong cac HCTS quan trong nhat va dUdc sii dung rong rai
trong ndng nghiep [41]. Do sU ton lUu lau dai trong mdi trUdng nen
ngay nay DDT da bi cam diing [133]. Nudc ta van cdn mot so ndi sii
dung DDT do cac ngudn budn lau dUa vao. Ndng dan sU dung DDT
trong khau khu triing dat, bao quan hat gid'ng [24, 61].
- DDT tich luy trong to chiic md cua ngUdi va dong vat, luan
chuyen trong cac ddi tUdng tU nhien cua mdi trUdng (dat, nUdc, khdng
khi, cay cd ...) Vi vay mac du da cam sii dung, ngUdi ta van tim thay
DDT va cac san pham chuyen hoa cua nd trong cac cd quan phii tang
ciia con ngUdi va dong vat [101, 106]. DDT va cac san pham chuyen

hoa ciia nd dUdc thai qua siia va nUdc tieu khoang 1% trong ngay. Khi
phan tich DDT d tre sd sinh nhan thay cd khoang 0,24 mg DDT trong 1
kg can nang ciia tre sd sinh do bii sUa me cd DDT [38]. Lieu chet ddi
vdi ngudi theo dudng tieu hoa la 20-30 g DDT d dang nguyen chat, neu
DDT d dang hoa tan trong dau thi chi can 14 g [38]. Theo Bui Thanh
Tam, neu udng n h a m tlii lieu gay nhiem doc la 3-5 g DDT tinh khiet
[41].
1.4.4.2.2. HCH - Hexacioxiclohexan, CQHQCAQ, M = 290,8
- HCH cd ttin goi : 1, 2, 3, 4, 5, 6 hexacioxiclohexan
- Cac ten khac : hexaclo, hexacloran, lindan, gamakan, 666 [124,
147]. H.Faraday tong hdp HCH tit nam 1925, Vander Linden tim ra
cac dang dong phan cua HCH va chiing dUdc dimg lam tlCBVTV tit nam
1935. Cd 8 dong phan cua HCH. Ngudi ta thUdng sii dung dong phan a

14


p, Y, 5-HCH nhUng chi cd dong phan y-HCH lacd dac tinh trii" sau rd ret.
Trong t h a n h phan HCH cd tH 10-12% chat boat hoa la dong phan y cd
70% dong phan a, cdn lai la cac dong phan khac. Khi trong HCH ky
t h u a t cd chiia 99% la dong phan y - HCH, thi goi la Lindan [124].
- HCH d dang tinh the mau tr^ng, mid khd ngiii. HCH hoa tan
trong cac hidrocacbon

chUa no va thdm, it tan trong cac dung mdi

liidrocacbon mach t h i n g va vdng no. d nhiet do phdng, HCH tan trong
nude vdi ti le lg/100 ml va trong etanol vdi ti le 6,4g/100 ml [38]. Diem
ndng chay cua HCH la 1120C [114].
- HCH ben vdi anh sang, nhiet do, khdng khi va vdi cac axit

manh, phan huy thanh triclobenzen va HCl trong mdi trUdng kiem,
- Doc tinh hoa hoc : LDQQ qua mieng 88 mg/kg, LD50 qua da 300
mg/kg, thudc nhdm doc loai II [124, 131].
- HCH la thudc trii sau cd hoat tinh cao, cd pho tac dung rong,
dUdc sii dung cho nhieu loai cay trong vi nd cd kha nang diet trit nhieu
loai sau hai : sau due than, bo canh ciing hai liia, ray nau. HCH ton
lUu lau dai trong mdi trUdng nen da bi cam sU dung [133, 1471. Lieu
cho phep trong mdi trUdng lao dong la 0,2 mg/m'^ khdng khi [41|. Tieu
chuan cua My gidi han 0,2-0,5 mg/kg dat. Mudn trong cac loai cay an
cu trong dat da xU ly HCH thi phai tien hanh sau thdi gian 4 n a m [61].
HCH di vao cd the va tich luy trong cac to chitc md, gan than,
nao [76, 147]. NgUdi ta da dinh lUdng HCH trong to chiic md va mau
cua ngudi tiep xiic vdi HCH . Ket qua cho thay : d md lUdng a-HCH
nhieu gap 363 lan, y-HCH nhieu gap 124 lan, (3-HCH nhieu gap 83 lan
so vdi ndng do cac chat nay cd trong mau [38, 147]. (^iing nhU DDT,
H(3H va cac san pham chuyen hoa ciia nd dUdc thai qua sUa me. Ngay

15


ca nhitng ngitdi khdng tiep xiic vdi HCH, trong sUa ciing cd HCH vi nd
ton lUu trong thitc an va nUdc udng [25, 35]. Theo Le Trung [54], Biii
Thanh Tam [41] Linda Rosens [37], bieu liien lam sang ciia nhiem doc
HCH giong nhu nhiem doc DDT, chi khac la bieu hien rd ret hdn. HCH
Cling gay nhiem doc cap tinh va man tinh, lam rdi loan mau va cd quan
tao man. HCH cdn cd tac hai tdi cac qua trinh chuyen hoa tao enzim d
gan va gay thoai hoa t e b a o gan [76, 92].
1.4.5. Tac hai chung cua HCBVTV nhom cd photpho
1.4.5.1. Dac tinh chung cua HCBVTV nliom ca photpho.
HCBVTV nhdm cd photpho dUdc diing rong rai va pho bien nhat

trong cac loai HCBVTV. Cac HCTS thudng dimg nhat la wofatox,
(metyl

parathion),

thiophot

(parathion),

diazinon

(basudin),

metamidophot (tamaron, monitor), clorophot ((hphterex), malathion
(cacbophot), systoc (mecatophot)...
a. Tat ca HCBVTV nhdm cd photpho deu cd chung cdng thiic
[106, 136]
RO
\

0^(S)
P

//

(S)

O day R la gd'c ankyi, X la gdc hiiu cd. Tuy theo oxi hay lUu
huynh chiem vi tri 1 hoac 2 ma ngUdi ta phan ra may loai nhU sau :
- Photphat:

P\
RO

P\
OX

C2H5O

0^^^N02

Paraoxon

16


Thiophotphat
R'
^

A
RO

// s
Pv

RO'^

OX

0-{^ V 0 2

^= Metylparathion : R la CH3
^= Parathion

:R la (^2^5

Dithiophophat
RQ

CHoO S
^ \ II
P
/ !
CH3O
S-CHCOOC2H5
CH2COOC2H5

.S

A
RO

SX

^-' Malathion
CH30^

S

CHsO^

S-CH2CONHCH3

Bi 58 (dimetoat)
- Clophotphat
(Flophotphat)

RO
RO

CI

(F)
- Photphatdiamidat

R2N^

^O

R2N'' ^ OX

b. Ndi chung trong cac hdp chat cd photpho khi S thay the cho O
thi hdp chat it doc hdn. TU nam 1938 den nay ngUdi ta da tdng hdp
dUdc 50.000 hdp chat cd photpho, cd 50 chat dUdc dung lam HCBVTV
[38, 56].
c. Ve boat tinh sinh hoc, cac hdp chat cd photpho deu rat doc ddi
vdi ngitdi va dong vat man ndng [98, 105, 106].
d. Tinh chat chung cda HCBVTV nhdm cd photpho [39, 92, 136]
f>(ft! -^or

• - - —

"-•'

";\.7" " ' . , . , : , \ . ' l ! i

17

^/
• • M * r ».^--'- ' *•


- Cac hdp chat cd photpho deu cd ap suat hdi cao, de bay hdi, la
nhfing chat doc dUdng ho hap. Chiing de hoa tan trong cac dung mdi
hiiu cd va dau md, d l bi phan huy nen „ khd t h u hdi dUdc chinh
p h a m ban dau.
*•
- Dac diem chung ve hoa hoc ciia cac hdp chat cd photpho la de
bi thuy phan.
RO.
RO P(S)
RO.
0(S)
HO
P = 0 + XOH
HO--P/
RO^
(S)
OX

II
RO^
OX
(S)
(S)
Tac n h a n thuy phan den gan chat phan ling va tan cdng vao
+0H-

RO

nguyen tii photpho. Budc (I) xay ra cham hdn, budc (II) xay ra nhanh,
tao t h a n h este ddn gian hdn ciia axit photphoric (day gd'c hfitu cd ra).
- Tinh chat quan trong thii hai la phan ling hoat hoa nhan
photpho. Phan ling xay ra thUdng tao thanh chat lic che enzim
cholinesteraza m a n h hdn, phan Idn chuyen nhdm y P=S t h a n h nhdm
\

p=o.
(C2H50)2 - P - o /

-a

\ N 0 2 + O2 + H2O ^ (C2H50)2 -P -0-(^

Parathion

^ NO2 + H2SO4

Paraoxon
- Di ddi vdi phan ling hoat hoa la phan uEng phan huy. Cac hdp

chat cd photpho chuyen hoa thanh d i n xuat trung gian kem doc hdn la
chat chinh pham. Dac diem nay cd the tim thay d dimetoat (Bi 58)

[106].
CH3O.
^ P
CHsO-^ ^ S-CH2CONHCH3 P h a n h u y

Dinaetoat (I)

CHsO.^
*~

CHsO"'^

S-CH2C00H

(90%)

(HI)

I;.''

(10%)
CHgO^

0

CH30

S CH2CONHCH3

r

Axit 0 , 0 -dimetyl dithiphotphoryl axetic

18


Axit 0 , 0 - dimetyl dithiphotphoryl axetic kem doc hdn dimetoat den
3.400 lan.
1.4.5.2. Dxidng xam nhap cua HCBVTV nhom ca photpho

vao ccf

the:
'^'

HCBVTV nhdm cd photpho xam nhap vao cd the qua dudng hd

hap, tieu hoa, da. Su hap thu cac hdp chat cd photpho d niem mac
dudng tieu hoa dien ra rat nhanh, chi sau vai phiit da xuat hien cac
dau hieu nhiem doc [76, 81]. Qua trinh hap thu qua da cham hdn,
khoang sau 2 gid mdi bat dau cd cac dau hieu ciia sU iic che enzim
cholinesteraza,nhttng dau hieu nay keo dai 2 ngay [38].
1.4.5.3. Chuyen hoa cua HCBVTV nhom cd photpho trong ccf the.
- HCBVTV nhdm cd photpho de tan trong lipit. Chiing dUdc hap
thu n h a n h chdng vao man, cac dich the cua to chiic va dat dUdc ndng
do cao trong cac synap than Idnh trung Udng va ngoai vi [41, 76].
HCBVTV nhdm cd photpho va cac san pham chuyen hoa ciia nd tap

trimg cao n h a t d gan va dUdc thai trit theo dudng tiet nieu [1, 105].
- HCBVTV cd photpho cd the phan huy thanh nhflng chat it doc
hdn, nhttng chat nay cd the hoa tan trong nUdc va thai t r ^ qua dUdng
tiet nieu [1, 105]
- HCBVTVcd photpho chuyen t h a n h dang khac, doc hdn, lic che
enzim cholinesteraza manh hdn [38, 57]. Qua trinh oxy hoa cac hdp
chat cd photpho dUdc thUc hien d gan, tao nen axit thiophotphoric va
dithiophotphoric. Ngoai ra cdn cd qua trinh thuy phan nhd phan ling
phophataza, cacboxylesteraza, cacboxylamindaza [76, 81, 83].

19


1.4.5.4. Ccf che nhiem doc
- HCBVTV cd photpho la nhiing chat doc ddi vdi nhieu enzim.
NhUng cd che nhiem doc chii yen la do iic che hoat dong cua enzim
cholinesteraza,

gay tinh trang tich luy nhieu chat axetylcholin dan

den nhiing rdi loan nghiem trong qua trinh dan truyen d cac synap
than kinh va hitng phan qua miic do he thdng than kinh trung Udng.
Vi vay chiing dUdc goi la nhiing chat doc than Idnh [81, 106].
- Binh thudng enzim chohnesteraza

tac dung vdi axetylcholin

Sau khi tac dung, enzim cholinesteraza dUdc hoi phuc nhd phan ling
thuy phan ciia hdp chat cholinesteraza-axetyl hoa.
- Trong trUdng hdp nhiem doc HCBVTV- cd photpho thi enzim

cholinesteraza ket hdp vdi phan tii HCTS cd photpho tao t h a n h hdp
chat ben viing, khd thuy phan, ket qua la enzim cholinesteraza bi iic
che [1,41].
- HCBVTV-cd photpho dUdc dung de : chdng sau benh cho cac
loai cay cdng nghiep, cay an qua, rau, liia mau, diet cd dai, chdng nam,
lam rung la, diet trii rudi, mudi, bo chet [12, 22, 28].
L 4.6. Gidi tbieu mot so HCTS-eaphotpho
1.4.6.1. Parathion

tbiidng diing :

[21, 117]

- Parathion cd cdng thiic tong quat: C10H14NO5PS, M = 291, 26,
; ' •

C2H5O

S

C2H5O

0(;^i>N02

\r^ -

Ten hoa hoc : 0,0 - Dietyl 0-p nitrophenyl photphothioat:

20

Ten khac : Alkron, bladan, folidol, E 605, etyl parathion,
thiophot...
Nam dang ky dau tien : 1948, Parathion la chat diet cdn triing
va sau bo. Parathion la chat long mau nau sam, miii gidng nhU miu
tdi, diem sdi : 157 - 162^0/ 0,6 mm Hg, ap suat hdi la 3,2.10-** mmHg d
30*^0. Parathion de tan trong cac dung mdi hiiu cd va dau, it tan trong
nUdc[117].
- Cung nhu cac HCTS-cd phopho, parathion de bi thuy phan.
Tinh chat quan trong thii hai la phan ling hoat hoa n h a n photpho,
phan ling xay ra thUdng tao t h a n h chat tie che enzim cholinestaraza
manh hdn. Trong cd the parathion chuyen hoa thanh paraoxon doc hdn
parathionlOOO lan [39, 56].
- Parathion thudc nhdm doc loai I. Hdp chat nay cUc ky doc vdi
dong vat cd vii [76], Parathion nhiem doc qua dUdng hd hap, da, tieu
hoa. Nd dUdc chiing minh cd tac hai man tinh nhU gay cac khoi u trong
thUdng than, chiing teo va thoai hoa vong mac va sU thoai hoa ciia day
than Idnh hdng. Cac tac gia da ket luan rang parathion la chat gay
khoi u loai C, cd kha nang gay ung thu tren ngUdi [98, 117]. LD50 la
13 mg/kg, A D I : 0,005 mg/kg the trong [114, 132].
- Cac dac diem ve sinh ly va sinh hoa : Parathion la chat diet cdn
triing. Parathion tac dong len ngudi bang each gay iic che khdng hdi
phuc enzim cholinesteraza, gay tich luy axetylcholin. Su nhiem doc
lam giam chiic nang ciia he than Idnh trung Udng [81, 136].
1.4.6.2 Metylparathion,

CgHioNOsPS,

M = 263, 2[138,

146]

Ten hoa hoc : 0,0-dimethyl 0,4-nitrophenyl-photphothioat

21