Xin cho thy c v cc bn!Click to edit Master subtitle style
5/26/12
MN DINH DNG V AN TON THC PHM
NHNG KIM LOAI NNG CO C TNH CAOClick to edit Master subtitle
style
GiNG VIN HNG DN: THS. NGUYN TH THANH LONG5/26/12
SVTH: H TH NGC UYN DNG TH THY NGN NGUYN NGC THY
KIM LOI NNG TRONG I SNG HIN NAY
Trong nhng nm qua, cng tc v sinh thc phm nc ta ang ng trc nhiu
thch thc. Nhiu v ng c cp tnh xy ra trong cc ba n gia nh v tp th lm
xn xao d lun v x hi. Tuy nhin, ch l phn ni ca vn ng c thc phm. Phn
chm chnh l tnh trng ng c mn tnh do thc n b nhim cc ho cht, cc kim
loi nng tch ly, gy hi trong c th 5/26/12
KHI NIM
Kim loi nng l nhng kim loi c khi lng ring ln hn 5g/cm3. Mt s kim
loi nng c th cn thit cho sinh vt, chng c xem l nguyn t vi lng. Mt s
khng cn thit cho s sng, khi i vo c th sinh vt c th khng gy c hi g.
Kim loi nng gy c hi vi mi trng v c th con ngi khi hm lng ca chng vt
qu tiu chun cho php. Hin ti c nhiu nguyn t kim loi nng c th l ngun
gy nhim thc phm, nhng nhng nguyn t 5/26/12
Lm suy gim chc nng thn kinh
nh hng ca c tnh kim loi nng5/26/12
Ri lon chc nng h thng min dch S mt cn bng pH v acid Bnh ng mch
vnh S suy gim nng lng Ri lon ni tit v h thng sinh sn Vic cha tr kh
khn v nh hng nhiu n sc khe
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1. Asen (As)
Asen hay cn gi l thch tn. K hiu As v s nguyn t 33. Khi lng nguyn
t ca n bng 74,92. Asen ln u tin c Albertus Magnus (c) vit v n vo nm
1250. Asen c nhiu dng th hnh: 5/26/12 mu vng (phn t
Asen v tnh cht ha hc rt ging vi nguyn t ng trn n trong bng tun
hon ha hc l photpho. S tng t ln n mc asen s thay th phn no cho
phtpho trong cc phn ng ha sinh hc v v th n gy ra ng c. Tuy nhin, cc
liu thp hn mc gy ng c th cc hp cht 5/26/12 asen ha tan li ng
vai
Trong thi k ng, asen thng c a vo trong ng thic lm cho hp kim tr
thnh cng hn (gi l "ng thic asen"). Anh, trong thi i Victoria,
'asen' ('asen trng' khng mu, kt tinh, ha tan) c trn ln vi dm v phn
v ph n n n ci thin nc da mt ca h, lm cho da mt ca h tr thnh nht mu
hn th hin h khng lm vic ngoi ng. Asen cng c c xt vo mt v tay ph n
'ci thin nc da'.5/26/12
Vic s dng ngu nhin asen trong lm gi
Ngun nhim Asen
Thc n, nc ung, kh th c cha arsenic.
Mt s thuc dc tho (n /Pakistan) c cha Asen Khai thc nc ngm c cha
Asen.
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Cng nhn lm vic trong nh my, c khng kh nhim bi As, lu ngy tch ly
trong c th. Ht khi khi t chy g c tm ha cht c cha arsen bo v chng mi
mt. Sng gn khu vc c thi khi nhim arsen.
c tnh ca Asen:
Asen v nhiu hp cht ca n l nhng cht cc k c . Asen ph v vic sn xut
ATP thng qua mt s c ch. chu trnh axt citric, asen c ch pyruvat
dehydrogenaza v bng cch cnh tranh vi phtphat n tho b phtphorylat ha
xi ha, v th c ch qu trnh kh NAD+ c lin quan ti nng lng, h hp ca ti
th v tng hp ATP. Sn sinh ca perxt hir 5/26/12 cng tng ln, iu ny c
th to
- Asen c th gy ra 19 cn bnh khc nhau. Cc nh hng chnh i vi sc kho
con ngi: lm keo t protein do to phc vi asen III v ph hu qu trnh
photpho ho; gy ung th tiu m da, phi, ph qun, xoang - Tiu chun nc
ung quy nh asen nh hn 0,01 mg/l.5/26/12
5/26/12
2. Ch (Pb)
Ch c k hiu l Pb v c s nguyn t l 82. Ch l mt kim loi mm, nng, c
hi v c th to hnh. Ch c mu trng xanh khi mi ct nhng bt u xn mu thnh
xm kh tip xc vi khng kh. Ch dng trong xy dng, c 5/26/12 quy ch, n,
v l mt
c tnh ca ch
Ch l nguyn t c c tnh cao i vi sc kho con ngi. Ch gy c cho h thn
kinh trung ng, h thn kinh ngoi bin, tc ng ln h enzim c nhm hot ng
cha hyro. Ngi b nhim c ch s b ri lon b phn to huyt (tu xng). Tu
theo mc nhim 5/26/12 c th b au bng, au khp, c
Nhim ch c th dn n v sinh, sy thai, mc phi ri lon v thn kinh. tr
em, ch s IQ s khng cao, i khi c nhng biu hin ri lon hnh vi. Do tch
lu trong c th mt cch chm chp nn cc triu chng s khng c nhn bit kp
thi. Ng c cp tnh t gp, thng din ra do n phi thc n c cha mt 5/26/12
ng ch, tuy t nhng lin tc hng l
2. Thu ngn(Hg):Khi vo c th, thy ngn s lin kt vi nhm sulfhydryl
lm thay i hot ng ca nhm -SH trong cu trc phn t ca cc enzyme. Thy
ngn ng li trong cc ng thn. Xut hin protein trong nc tiu. Khi vo c
th thy ngn bin i thnh dng methyl thy ngn i khp ni trong c th v n ha
tan c trong lipid nn c kh nng tch t li 5/26/12
Thu ngn d bay hi nhit thng nn nu ht phi s rt c. Thu ngn c kh nng
phn ng vi axit amin cha lu hunh, cc hemoglobin, abumin; c kh nng
lin kt mng t bo, lm thay i hm lng kali, thay i cn bng axit baz ca
cc m, lm thiu ht nng lng cung cp cho t bo thn kinh. Tr em b ng c
thu ngn s b phn lit, co git khng ch ng. Trong nc, metyl thy ngn l
dng c nht, n lm phn lit nhim sc th v ngn cn qu trnh phn chia t bo.
- Tiu chun nc ung v nc sch u quy nh hm lng thy ngn phi nh hn 0,001
5/26/12
Ngi ph n Nht vi a con ca mnh l nn nhn ca bnh "Minamata Disease",
do nhim c thy ngn Minamata, Nht bn, nm 1973. a con gi d hnh trong
vng tay ca m, cng nh nhiu b m khc mc phi chng bnh ny c lin quan n
nn cng nghip phn bn, ha du m v cng nghip cht do... xung vnh
Minamata khang 27 tn thy ngn t nm 1932 n 1968 Nht Bn lm cho trn
10,000 dn chu nh hng do n hi sn ni ny.5/26/12
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Ng c Hg c th xy ra t cht liu hn hp trm rng trc y
5/26/12
4. Cadimi (Cd)
L nguyn t kim loi tng i mi vi con ngi Ngun nhim:
S bo mn t nhin c cha Cadmium L nu ng, ch v km lm bay ra cadmium
Ht thuc l (mi iu thuc cha 1-2 g Cd) M kim loi Lm pin sc
Nickel-Cadmium. Hp kim hn Lm mu sn (xanh nc bin) Cht n nh cht do.
Ha cht trong k thut nhip nh
Nhng ng dng Cadmium:
5/26/12 thuc dit nm Lm
C ch tc ng:
Gn vo nhm SH Cnh tranh vi Zn v Se cho tt c cc metalloenzyme Cnh
tranh vi calcium v tr gn (calmodulin) Cd t do gn vo tiu cu thn Lm
mt chc nng ca ng ln gn trong thn. Vim ph v kh thng phi bi cadmium
git cht i bch cu phi
c tnh i vi thn:
c hi phi:
5/26/12
nh hng ln b xng:
Gy long xng v nhuyn xng (pseudofractures) Gy ung th trn ng vt th
nghim ~8% ca ung th phi c th qui cho l do Cdmium Tiu chun nc ung
quy nh Cadimi nh hn 0,003 mg/l.
Gy ung th:
5/26/12
Itai-itai victim
5.Km (Zn)Km l thnh phn t nhin ca thc n v cn thit cho i sng con
ngi. Mt khu phn mu cung cp hng ngy t 0,17 n 0,25 mg Zn/kg th trng.
Ni chung, tt c cc loi ng vt u chu ng c km, kim loi m t gy c nu hm
lng thp v khu phn n cha nhiu ng, st v chu tc ng tng h gia cc yu t
khc.5/26/12
Do c gii hn bo m chc chn gia nng km c trong khu phn n bnh thng
hng ngy, vi liu lng km c th gy ng c do tch lu, cho nn vi hm lng km
c quy nh gii hn trong thc n (t 5 n 10 ppm) khng nh hng n sc khe ngi
tiu dng.
Ng c do km cng l ng c do cp tnh, do n nhm phi mt lng ln km (510g
ZNSO4 hoc 3-5ZnCl2) c th gy cht ngi vi triu chng nh c v kim loi kh
chu v dai dng trong ming, nn, tiu chy, m hi lnh, mch p kh, cht sau
10 n 5/26/12
Quyt nh s 867/1998 BYT ngy 4/4/1998
5/26/12
CM N S THEO DI CA THY C V CC BN!
5/26/12
