PTTP. Nuoc Giai Khat

8/2/2019 PTTP. Nuoc Giai Khat

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Phn 1

NC NGT GII KHTYU CU V SINH V PHNG PHP TH

I/ YU CU V SINH:

1/ Ch tiu ho v sinh:

Mt s yu cu trong nc gii kht:

_Khng s dng axit v c (HCl, HNO3, H2SO4,)._Hm lng kim loi nng (mg/l), theo quy ng cu B Y t (Q 505, 4-

1992).

_Cc cht ph gia trong nc gii kht ch c s dng theo danh mc hin

hnh.

_Cc ph gia mi, nguyn liu mi ch s dng khi c s cho php cu B

Y t.

_Cht ngt tng hp (Saccrin, dulsin, cyclamat,) khng c s dng pha chnc gii kht. (Trng hp sn phm dnh cho ngi king ng

phi xin php B Y t v ghi r tn ng + mc ch s dng).


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2/Ch tiu vi sinh vt:

_i vi nc gii kht khng cn:

Tn ch tiu

Mc

Khng ng chai ng chai

1. Tng s vi khun hiu kh,

s khun lc/ml, khng ln

hn

5.104

102

2. E. Coli, con/l, khng ln hn 3 Khng c c

3. Cl. Perfringers Khng c c

4. Vi khun gy nhy,

(Leuconotoc)

Khng c c

5. Nm Men-mc, s khn

nm/ml. khng ln hn

103 Khng c c

6. St. aureus Khng c c


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_i vi nc gii kht c cn thp

Tn ch tiu

Mc

Khng ng chai ng chai

1. Tng s vi khun hiu kh,

s khun lc/ml, khng ln

hn

103

102

2. E. Coli, con/l Khng c c

3. Cl. Perfringers Khng c c

4. Vi khun gy c, quan st

bng mt

Khng c c

5. Nm Men-mc, s khn

nm/ml. khng ln hn

102 Khng c c

6. St. aureus/vi khun gy bnh

ng rut

Khng c c


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II/ PHNG PHP TH:1/ Ly mu:

_Mu phi nm trong thit b sch v kh._Ly mu mt cch ngu nhin ( ly 4 gc v ly gia).

_Cn lp bin bn khi ly mu ghi r s l hang, cng ty sn xut, khilng, ngy thng, ni ly mu, ngi ly v giao mu (ghi r tnh trng camu).

2/Xc nh axit v c trong nc gii kht:Nguyn tc: Cc nc gii kht nhn to pha ch t nc ng vi axit

hu c (axit xitric, axit tactric hoc axit lactic) vi chua ton phn tnh raaxit xitric khong 1g/1000ml, pH trn 2. Nu cho thm axit v c nh HCl,HNO3, H2SO4l nhng axit mnh, pH s gim. C th xc ng bng pH

mt hoc ch th mu.

a/ Dng c, vt liu, thuc th:_pHmt, +-0,1 pH

_Cao lanh sch. _Dung dch axit xitric C 1%

Axit xitric khan 1g

Nc ct v 1000 ml_Dung dch Metyl tm 0,1% trong nc ct.

b/ tin hnh th:_Sau khi thy xc nh chua ton phn cu nc gii kht, tnh v iu

chnh sao cho chua bng 0,1% (tnh theo axit xitric). (Nu nc gii khtc mu, th bng cch lc 50 ml ncgii kht vi 1-2g cao lanh v lc,dch lc khng mu).

_Sau khi lc cho vo ng nghim: ng 1 cha dch lc nc gii kht 20mlv cho 5 git dd metyl tm 0,1%. ng 2 cho 20ml dd axit xitric 0,1% v 5git metyl tm 0,1%.*Ch : dd trong ng 1 khng c mu xanh lc hn hnaxit xitric trong ng2

C xc ng dung ch dd mu v i chng bng pH-mt .

3/ Xc nh hm lng kim lai nng:Thc phm ni chung thng hay b nhim cht c t nhiu ngun khcnhau:


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*Do thc phm sn xut, bo qun thc phm dng khng ngnguyn tc cc dng c chang cng nh v sinh cc dng cc l t,st, km, ng, v s lm thay i nhiu trong cc loi thc phm c tnhaxit ln nh nc qu, sp ln men,.

Nhi n phi thng nn ma, nhc u, ri lon tiu ho,Nucht c mnh th s dn n t vong.

*Sau y l hm lng tia c cho php trong tiu chun thcphm, da vo ti liu Phn tch ho thc phm trang 242.Cu -> Ung th (0,05 mg/kg th trng trong 1 ngy).Pb -> Ngc cp tnh (0,05 mg/kg)V cc cht khc.

*Mt s phng php xc nh Cu, Pb, Zn, Sn trong dd mu.+Cn v cho mu (pp kh- t).+Bn cnh cn c s s phng php khc:

_Zn, Pb dng pp so mu._Sn dng phng php iot._Axen dng pp so mu bng giy tm thu ngn (II) clorua.

+Phng pp cc ph phn tch kim loi nng:Nguyn tc:o mt quang ca dung dch. Sau suy ra nng da

vo nh lut hp th v hp ph nh sng ca LambertBeer.+Ngoi ra cn nhiu ohng php khc:

.Kthut ph.

.UV, Vis, hunh quang.

.Hng ngoi.

.Ph hp th nguyn t.

.Ph khi (MS).

.Sc k.

.Sc k lng hiu nng cao (HPLC).

.Sc k kh (GC).

4/Xc nh phm mu:_Phm mu food grade l iu bt buc trong nc ngt.

5/ Xc nh cht tng hp (Sacarin, dulsin,cyclamate):

y l nhng cht to ngt ha hc c nh hng x n sc khe cbt k sacarin.

a/ Phng php ha hc:


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Nguyn tc: Da vo phn ng gia Sacarin vi FeCl2, gia Cyclamat viBaSO4 trng mi trng axit, gia axit xitricvi dulcin nhn bit.

*Xc nh nh tnh Sacarin:Cch 1:

+Dng c v thuc th:_Phu chit (250ml)._ng ong (50ml,25ml)._Bt s._Bp cch thy._Ete etylic.

_NaOH

_FeCl3 2%.

_H2SO4 10%.

_HCl.

+ Tn hnh:

Cho 50 ml mu vo phu 250ml+ 5ml HCl v 50ml ete etylic chitsacarin. Phn ete etylic c gi li trong phu cht. Sau ra sch bngnc ct.Chuyn ete sau khi ra sch sang bt s v lm bay hi trn bpcch thy, khi gn cn th em ra ngai phi kh t nhin. Them vo cn thuc 1-2 vin natri hydroxit + vi got nc ri em nung 200-220oC rilm ngui v ha tan bng 10ml nc ct. Sau 1o cho vo 15ml H2SO4 v3-5 FeCl3 nu c mu tm th c sacarin.

Cch 2:.Mu l dung dch lng, nh nc gii kht phi lc u chai trc khi lymu phn tch.

+Tin hnh: Cho vo becher dung tch 100ml, khong 50 100ml mu (chun b phn 3.1 hoc 3.2), thm 5ml ch axetat 30%, lc u. Sau chokhong 0,5 10ml dung dch HCl m c kt ta lng ch thuc lcu v lc qua giy lc. Dung dch ny c trch 3 ln, mi ln vi 25mlete etilic v 0,2ml axit HCl m c trong bnh lng. Ete sau mi ln trchc gi trong chn y trn bng s. Sau lm bay hi cho cn trn bpcch thy. Ha tan cn trong nc ct, lc li 2 ln vi ete etylic (mi lnkhong 10ml ete), lm bay hi n cn, nm cn, nu c v ngt thc hintip phn nh tnh saccarin.Ha tan cn trong chn vi 2ml nc ct v 4-5 git Natrihidroxit 30%. Lm

bay hi cho cn, cho thm 2ml nc ct v lm bay hi n cn mt ln na.Sau nung chn nhit 170-200C trong 20 pht. ngui, ha tan


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cn vi 2ml ncct. Trung ha bng axit clohidric m c n khi imu giy qu tm. Cho vi git clorua st III, 0,1N (c mu vng nht) nuc saccarin dung dch s c mu tm.

*Xc nh nh tnh cyclamate:

+Dng c v thuc th:_Cc c m 250ml._ng ong 100ml._BaCl2.

_natri nitric.

_HCl

+Tin hnh:Cho 100ml mu vo cc 250ml + 2g BaCl2+ 1ml HCl sau lc u ri yn 5 sau lc. Thm 0,2g natri nitric vo dd lc, nu c mu trng th lcyclamate.

*Xc nh nh tnh dulsin:+Dng c v thuc th:

_T sy 110oC sai s 5oC._Phu 250ml._Bt s._ng ong 100ml v 50ml._Axit nitric.

+Tin hnh:Cho 100ml mu th ( kim ha bng dd NaOH 10% nu cn) vo phu250ml, tin hnh chit 3 ln mi ln 50ml ete etylic. Gp cc ete chit vobt s sau chia lm 2 bay hi nhit phng ri sy kh nht 110

oC. Ly cn ri ngui v lm m v HNO3+ vi git nc ct. Nu

xut hin mu cam th trong mu c dulcin.

b/Phng php sc k bn mng:*Ni dung:

Chit tch cht ngt trong nc gii kht bng etylaxetat. C cdung dch chit ri chm dung dch ny trn bn sc k lp mng.Cc vit chm s c nhn thy hoc di nh n t ngai vi

bc song 254nm hoc bng cc cht hin mu.

6/ Xc nh cc ch tiu vi sinh vt:


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a/ Pht hin trc khun E.Coli:Nguyn tc: Nui cy mu th trong mi trng canh thang, chnlc nhit 44oC trong 12 ngy (nhn nh E.Coli trong muth qua cc c im hnh thi v c tnh sinh ha nh sinh hi

hoc ln men lactoza.

b/ Thit b v dng c:Nhng dng c thng dng.

c/ Tin hnh:*Dng ng ht v khun, cy vo 2 ng nghim c cha mitrng canh thang chn lc; mi ng 1 ml. Tin hnh nui cy 1-2ngy vi nhit 44oC.

*c kt qu s b. Nu thy m tnh (khng sinh hi, trong sut,khng chuyn mu) th nui trong t m trong 1 ngy vi nhit 44

oC.

*nu mu sinh hi, c hay lm bin mu mi trng th ria cyln b mt mi trng Endo sau a vo t m 18:24 gi vinhit 37oC.* Trn b mt thch Endo nu xut hin khun lc in hnh ( hng, mu nh kim) th tin hnh nhum gram v soi tiu bn quanst hnh thi vi khun.

Nhim php (IMVIC): Chn khng t hn 3 vi khun lc inhnh cy chuyn bng que cy ng hi sang mi trng : ncpeptone kim tra tnh sinh indolm mi trng canh thang th

phn ng MR v VP, mi trng thch ng nghing Simmon khim tra ng ha xitrat. Cc mu nui nhit 37oC.*Sau 24 gi, tin hnh th tnh sinh indol bng cch cho vo ngnc pepton cy mu khang 0,2 0,3 ml thuc th KOVACS.

Nu phi ng c lp mu th dng tnh, cn c mu vng hay

nu nht l m tnh.*Sau 48 gi th phn ng M.R v V.P bng cch: t ng canhthang nui cy. Ly 0,7 ml dch cy cho phin thy tinh + 0,1ml

naphton 5% trong cn, 0,1 ml KOH 40% . trong 2 gi phnng V.P dung tnh khi xut hin mu hng.


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*Dch cy cn li trong ng nghim em th M.R + 5 git metyl, dd chuyn sang mu th dng tnh.*Sau 24-72 gi, quan st vt cy trn ng nghim Simmon nukhng thy vi khun mc khng lm chuyn mu mi trng th

phn ng l m tnh (dng tnh khi c mu t lc nht sang xanhlam).

d/ Nhn nh v bo co kt qu:Mu th c coi l c E.Coli nu pht hin trc khun ngn,gram m, khng sinh bo t, ln men lactoza, sinh hi v cho phnng IMVIC lai (++--) hoc (-+--).

7/Phng php th ch tiu Natribenzoat trongNGK khng c cn:da trn 169/Q-UB 11/11/1986.a/Ni dung:

Chit axit benzoate bng dung mi hu c, lm ri cn cn cn li.b/Dng c, ha cht

_Bp in._T sy 105oC._Gin chng ct.

_Bnh cu 150ml v 250ml._Bnh lng 250ml._HCl 10%.

_DD chloroform tinh khit._Axit tartaric tinh th hay dd 10%._Cn phn tch chnh xc n 0,0001g.

c/Tin hnh th:Ly chnh xc khong 50ml 100ml mu th cho vo bnh cu dung tch150ml thm mt t axit tartric cho n khi mi trng lm i mu giy tholam v vi vin bt. Lp bnh cu cho gin chng ct v tin hnh chngct n cn khong 10ml, sau cho thm 50ml nc ct v tip tc chngct cho n khi dung dch hng c khong 100ml. Chuyn dung dch ctc vo bnh lng dung tch 150ml, trch dung dch ct 3 ln, mi ln vi


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50ml clroform v 5ml axit HCl 10%. Phn cloroform trch c cho vobnh cu dung tch 250ml, cho vi vin bt v tin hnh chng ct thuhi cloroform cho n khi trong bnh cu cn khong 20ml, lm ngui vchuyn dung dch cn li trong bnh chng ct sang bnh cu khc dung tch150ml ( bit khi lng), trngbnh chng ct bng cloroform 3 ln, miln vi 5ml v cho ht dch trng vo bnh cu 150ml. Lm bay hicloroform n va cn, em sy 60 70C trong 15 pht, lm ngui bnhcu trong bnh ht m v cn+Tnh kt qu :

Hm lng Natribenzoat (X) tnh ra mg/l theo cng thc sau:

X =(G1G0) x 1000 x 1

x

144

122

G1:Khi lng bnh cu v axit benzoic sau khi lm ngui (g).G2: Khi lng bnh cu (g).144: Phn t lng ca Natribenzoat (g).122: Phn t lng axit benzoic (g).M: H s chuyn i ra lt.1000:H s chuyn i ra mg.


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8/ o th tch CO2 trong nc ngt:

Nguyn tc:dng 1 lng d Na2CO3 0,2N tc dng vi CO2 c trong mu NGK. Sau

chun lng d bng dd HCl 0,1N vi ch th PP.T tnh ra hm lng C c trong mu th:CO2 + H2O + Na2CO3 = 2NaHCO3

Na2CO3(d) + HCl = NaCl + NaHCO3Chun n khi mt mu hng ca pp

Tin hnha/ Lm mu chnh

_Lm lnh nc gii kht trong 2-3 gi t nhit t 1-3oC (trnh choCO2bay hi)

_Ht 15ml dd Na2CO3 0,2 N cho vo bnh tam gic. Sau dng pipet ht10ml nc gii kht( lm lnh) cho vo bnh tam gic cha dd Na2CO30,2 N bng cch cm su u pipet vo dd Na2CO30,2 N ri th t t chon khi nc gii kht trong pipet xung ht. Cho thm 3 git pp 1%. Lcny dd c mu hng m. Chun dd trong bnh tam gic bng HCl 0,1Ncho n khi mt mu hng th dng li, ghi th tch tiu tn ca HCl.

b/ lm mu trngl mu loi ht CO2( cho vo cc thy tinh dng a khuy u cho CO2

bay i). Kt qu l:

:


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9/Phng php xc nh ch v chit chun :da vo tiliu phn tch ho thc phm trang 247-249.

Trong mi trng trung tnh hoc kim (Pb2+) to vi ditizon -> ditizonat

mu tm trong dung mi hu c.Pb

2++ 2H2D2 -> Pb (HDZ) + 2 H

+.

Trong Cloroform, Pb(HDz)2 tng gp 17 ln tetraclorua.Do dng Cloroform ho tan.

Ta c: X= 3,45a.V.100.V1-1

.V0.

Trong : a: Th tch ditizon chun .

V1: Th tch ht ra bnh nh mc phn tch. (ml).Vo: Th tch lng v c ho mu. (ml).

Ch : Phng php ny cn tin hnh cn thn v d mc sai s,do nh gitditizon d b d git cui. Dng pp so mu cng l mt phng php tt.

Phn 2

NCUNG TINH KHIT

*Bn cnh cc sn phm c ga th cc lai nc khang, nc ung tinhkhit cng cn c quan tm.*Quy trnh chun sn xut nc ng chai:

S lc:Gm 2-3 cp lc ha l ty theo cht lng nc ngun; c nhim v nngpHkh st, mangan v cc cht nhim kh mi hi, mi clo d kh khong, lm mm nc loi b cn ln.


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Tinh lc:Gm 1-2 cp lc bng mng cartridge vi khe rng 5um-1um; c nhim vloi b cn nh kch thc ln hn 1um.

Lc thm thu ngc:Dng mng lc theo cng ngh thm thu ngc (RO) ch cho ra thnh

phm l H2O, cc vt th l khc b tch ra khi nc v thi b. y lcng on ch yu ca quy trnh sn xut nc tinh khit, cc cng ontrc ch nhm h tr cho cng on RO hot ng tt v bn, v gi camng RO kh cao. Cn lu trnh nhm ln gia mng RO vi mng UF,

NF v chng c "ngoi hnh" rt ging nhau, nhng cng dng ca 2 loikia ch l siu lc, vi lc m thi.

iu chnh pH v b sung vi lng khong cht:y l cng on tngcng dnh cho quy trnh sn xut nc ung ng ngha, bi v nc tinhkhit sau RO ch c H2O nn thiu cc khong cht c li cho c th,

pH c th nh hn 7 v c v lt. Cng on ny ch c s dng ha chtdnh cho cng ngh chbin thc phm v phi c tinh lc li bngmng c kch thc khe h 0.1-0.2um.

Tit trng:y l khu cui cng rt quan trng x l vi sinh cho ncthnh phm trc khi ng bnh ng chai. Tit trng qua 3 ln: ln 1 dng tia cc tm UV cho dng nc trc khi vo bn cha; ln 2 dng

kh ozone sc thng vo bn cha; ln 3 - dng UV cho dng nc chitrt ngay trc khi v bnh ng chai. Ozone cng tit trng nh UV nhngc thm cng dng chng rong ru cho nc lu tr lu, gip tng thi hn

bo qun sn phm.

Lu : Cng on tit trng ny s v ngha nu nh phng chit rt khngt yu cu v v trng khng kh cng nh tnh trng v sinh v sc kheca ngi tham gia sn xut khng m bo, v sinh v bnh v chai khngt. V th, ngoi cc cng on k thut ca quy trnh nu trn, cn cc yut khc b cho l ph trong sn xut nhng li c th tc ng rt nhiu ncht lng nc:

iu kin v sinh ca nc ngun khai thc; iu kin mt bng kho xng sn xut; Cch thc vn hnh quy trnh x l nc; Tnh trng v sinh v sc khe ca ngi tham gia sn xut;


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iu kin bo qun sn phm.Tt c nhng yu t ny u c B Y T quy nh cht ch, vn cn lil mc tun th ca nh sn xut.

*Ngai ra cn lu cc yu t t cc ngun nc lm nc tinh khit:

Cc yu t

1. Mi vNc ging ngm: mi trng thi l do c kh H2S, kt qu ca qu trnhphn hy cc cht hu c trong lng t v ha tan vo mch nc ngm.Mi tanh ca st v mangan.

Nc mt (sng, sui, ao h): mi tanh ca to l do s xut hin ca cc

loi to v vi sinh vt. Trong trng hp ny nc thng c mu xanh.Nc my: mi ha cht kh trng (clo) cn d li trong nc.=>Mi v khc l s gy cm gic kh chu khi dng nc. Tu theo loimi v m c cch x l ph hp nh dng ha cht dit to trong ao h, keot lng lc, hp ph bng than hot tnh,..


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2. MuMu vng ca hp cht st v mangan.Mu xanh ca to, hp cht hu c.=>Nc c mu cao thng gy kh chu v mt cm quan. Vi cc quy

trnh x l nh sc kh ozn, clo ha s b, keo t, lng lc c th lm gim mu ca nc. Cn lu , khi ngun nc c mu do hp cht hu c,vic s dng Clo c th to ra cht mi l trihalomethane c kh nng gyung th.

3. pH-Ngun nc c pH > 7 thng cha nhiu ion nhm carbonate v

bicarbonate (do chy qua nhiu tng t ). Ngun nc c pH < 7 thngcha nhiu ion gc axit.

Bng chng d thy nht lin quan gia pH v sc khe ca ngi s dng l n lm

hng men rng.

=>pH ca nc c lin quan n tnh n mn thit b, ng ng dn nc v dng c

cha nc. c bit, trong mi trng pH thp, kh nng kh trng ca Clo s mnh

hn. Tuy nhin, khi pH > 8,5 nu trong nc c hp cht hu c th vic kh trng bng

Clo d to thnh hp cht trihalomethane gy ung th.

Theo tiu chun, pH ca nc s dng cho sinh hot l 6,0 8,5 v ca nc ung l 6,5

8,5.

4. c

c l i lng o hm lng cht l lng trong nc, thng do shin din ca cht keo, st, to v vi sinh vt.

Nc c gy cm gic kh chu cho ngi dng v c kh nng nhim visinh. Tiu chun nc sch quy nh c nh hn 5NTU, nhng gii hnti a ca nc ung ch l 2 NTU. Cc quy trnh x l nh keo t, lng, lcgp phn lm gim c ca nc.

5. kim

kim ca nc l do cc ion bicarbonate, carbonate v hydroxide tonn. Trong thnh phn ha hc ca nc, kim c lin quan n cc ch


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tiu khc nh pH, cng v tng hm lng khong. Vic xc nh kim ca nc gip cho vic nh lng ha cht trong qu trnh keo t, lmmm nc cng nh x l chng n mn.

Hin nay, khng c bng chng c th no lin quan gia kim v sckhe ca ngi s dng. Thng thng, nc dng cho n ung nn c kim thp hn 100 mg/l.

6. cng

cng l i lng o tng cc cation a ha tr c trong nc, nhiu nhtl ion canxi v magi. Nc mt thng khng c cng cao nh ncngm. Ty theo cng ca nc ngi ta chia thnh cc loi sau:

cng t 0 50mg/l -> Nc mm cng t 50 150mg/l -> Nc hi cng cng t 150 300mg/l -> Nc cng cng > 300mg/l -> Nc rt cng

Nc cng thng cn nhiu x phng hn to bt, hoc gy hin tngng cn trng trong thitb un, ng dn nc nng, thit b gii nhit hayl hi. Ngc li, nc cng thng khng gy hin tng n mn ng

ng v thit b.Theo tiu chun nc sch, cng c quy nh nh hn350 mg/l. i vi nc n ung, cng nh hn 300 mg/l. Tuy nhin, khi cng vt qu 50 mg/l, trong cc thit b un nu xut hin cn trng.Trong thnh phn ca cng, canxi v magi l 2 yu t quan trngthng c b sung cho c th qua ng thc n. Tuy nhin, nhng ngic nguy c mc bnh si thn cn hn ch vic hp th canxi v magi hm lng cao.

C th kh cng bng phng php trao i ion.

7. Tng cht rn ha tan (TDS)

TDS l i lng o tng cht rn ha tan c trong nc, hay cn gi l tngcht khong.


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Tiu chun nc sch quynh TDS nh hn 1.000 mg/l. Tiu chun ncung quy nh TDS nh hn 500 mg/l.

8. oxy ha (Cht hu c)

oxy ha c dng nh gi mc nhim ca ngun nc. C 2phng php xc nh oxy ha ty theo ha cht s dng l phng phpKMnO4 v K2CrO7.

Tiu chun nc sch quy nh oxy ha theo KMnO4) nh hn 4 mg/l.Tiu chun nc ung quy nh oxy ha (theo KMnO4) nh hn 2 mg/l.

9. Nhm

Nhm l thnh phn chnh trong cc loi khong, t st. Nhm cdng trong cc ngnh cng nghip sn xut cht bn dn, thuc nhum, snv c bit l ha cht keo t trong x l nc. Nc khai thc t vng tnhim phn thng c pH thp v hm lng nhm cao.

Nhm khng gy ri lon c ch trao i cht, tuy nhin c lin quan ncc bnh Alzheimei v gia tng qu trnh lo ha. Tiu chun nc ung quynh hm lng nhm nh hn 0,2 mg/l.

10. St

Do ion st hai d b oxy ha thnh hydroxyt st ba, t kt ta v lng nn stt tn ti trong ngun nc mt. i vi nc ngm, trong iu kin thiukh, st thng tn ti dng ion Fe2+ v ho tan trong nc. Khi c lmthong, st hai s chuyn ha thnh st ba, xut hin kt ta hydroxyt st ba

c mu vng, d lng. Trong trng hp ngun nc c nhiu cht hu c,st c th tn ti dng keo (phc hu c) rt kh x l. Ngoi ra, nc c pH thp s gy hin tng n mn ng ng v dng c cha, lm tnghm lng st trong nc.


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St khng gy c hi cho c th. Khi hm lng st cao s lm cho nc cv tanh, mu vng, c v mu tng nn kh s dng. Tiu chun ncung v nc sch u quy nh hm lng st nh hn 0,5 mg/l.

11. Mangan

Mangan thng tn ti trong nc cng vi st nhng vi hm lng t hn.Khi trong nc c mangan thng to lp cn mu en ng bm vo thnhv y bn cha.

Mangan c c tnh rt thp v khng gy ung th. hm lng cao hn0,15 mg/l c th to ra v kh chu, lm hoen qun o. Tiu chun ncung v nc sch u quy nh hm lng mangan nh hn 0,5 mg/l.

12. Asen (thch tn)

Do thm qua nhiu tng a cht khc nhau, nc ngm thng cha asennhiu hn nc mt. Ngoi ra asen c mt trong ngun nc khi b nhimnc thi cng nghip, thuc tr su.

Khi b nhim asen, c kh nng gy ung th da v phi. Tiu chun ncsch quy nh asen nh hn 0,05 mg/l. Tiu chun nc ung quy nh asen

nh hn 0,01 mg/l.

13. Cadimi

Do thm qua nhiu tng a cht khc nhau, nc ngm thng cha hmlng cadimi nhiu hn nc mt. Ngoi ra Cadimi cn thy trong ngunnc bnhim nc thi cng nghip khai thc m, nc r bi rc. Cadimic th xut hin trong ng ng thp trng km nu xy ra hin tng nmn.

Cadimi c tc ng xu n thn. Khi b nhim c cao c kh nng gy ima. Tiu chun nc ung quy nh Cadimi nh hn 0,003 mg/l.


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14. Crm

Crm c mt trong ngun nc khi b nhim nc thi cng nghip khaithc m, xi m, thuc da, thuc nhum, sn xut giy v gm s.

Crm ha tr 6 c c tnh mnh hn Crm ha tr 3 v tc ng xu n ccb phn c th nh gan, thn, c quan h hp. Nhim c Crm cp tnh cth gy xut huyt, vim da, u nht. Crm c xp vo cht c nhm 1(c kh nng gy ung th cho ngi v vt nui). Tiu chun nc ung quynh crm nh hn 0,05 mg/l.

15. ng

ng hin din trong nc do hin tng n mn trn ng ng v ccdng c thit b lm bng ng hoc ng thau. Cc loi ha cht dit toc s dng rng ri trn ao h cng lm tng hm lng ng trongngun nc. Nc thi t nh my luyn kim, xi m, thuc da, sn xutthuc tr su, dit c hay phim nh cng gp phn lm tng lng ngtrong ngun nc.

ng khng tch ly trong c th nhiu n mc gy c. hm lng 1 2 mg/l lm cho nc c v kh chu, v khng th ung c khi nng

cao t 58 mg/l. Tiu chun nc ung v nc sch u quy nh hmlng ng nh hn 2 mg/l.

16. Ch

Trong ngun nc thin nhin ch pht hin hm lng ch 0,4 0,8 mg/l.Tuy nhin do nhim nc thi cng nghip hoc hin tng n mn ng

ng nn c th pht hin ch trong nc ung mc cao hn.

Khi hm lng ch trong mu cao c th gy tn thng no, ri lon tiuha, yu c, ph hy hng cu. Ch c th tch ly trong c th n mc caov gy c. Tiu chun nc ung v nc sch u quy nh hm lng chnh hn 0,01 mg/l.


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17. Km

Km t khi c trong nc, ngoi tr b nhim t ngun nc thi ca cckhu khai thc qung.

Cha pht hin km gy c cho c th ngi, nhng hm lng > 5 mg/l lm cho nc c mu trng sa. Tiu chun nc ung v nc sch uquy nh hm lng km < 3mg/l.

18. Niken

Niken t khi hin din trong nc, ngoi tr b nhim t ngun nc thica ngnh in t, gm s, c quy, sn xut thp.

Niken c c tnh thp v khng tch ly trong cc m. Tiu chun ncung v nc sch u quy nh hm lng niken nh hn 0,02mg/l.

19. Thy ngn

Thy ngn him khi tn ti trong nc. Tuy nhin cc mui thy ngn cdng trong cng ngh khai khong c kh nng lm nhim ngun nc.

Khi nhim c thy ngn cc c quan nh thn v h thn kinh s b rilon. Tiu chun nc ung v nc sch u quy nh hm lng thyngn nh hn 0,001 mg/l.

20. Molybden

Molybden t khi c mt trong nc. Molybden thng c trong nc thingnh in, ha du, thy tinh, gm s v thuc nhum.

Molybden d hp th theo ng tiu ha v tn cng cc c quan nh gan,

thn. Tiu chun nc ung quy nh molybden nh hn 0,07 mg/l.

21. Clorua


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Ngun nc c hm lng clorua cao thng do hin tng thm thu tnc binhoc do nhim t cc lai nc thi nh m km, khai thc du,sn xut giy, sn xut nc t quy trnh lm mm.

Clorua khng gy hi cho sc khe. Gii hn ti a ca clorua c lachn theo hm lng natri trong nc, khi kt hp vi clorua s gy v mnkh ung. Tiu chun nc sch quy nh Clorua nh hn 300 mg/l. Tiuchun nc ung quy nh Clorua nh hn 250 mg/l.

22. AmniNitrit - Nitrat

Cc dng thng gp trong nc ca hp cht nit l amni, nitrit, nitrat, lkt qu ca qu trnh phn hy cc cht hu c hoc do nhim t nc

thi. Trong nhm ny, amni l cht gy c nhiu nht cho c v cc loithy sinh. Nitrit c hnh thnh t phn ng phn hy nit hu c vamni v vi s tham gia ca vi khun. Sau nitrit s c oxy ha thnhnitrat. Ngoi ra, nitrat cn c mt trong ngun nc l do nc thi t ccngnh ha cht, t ng rung c s dng phn ha hc, nc r bi rc,nc ma chy trn. S c mt hp cht nit trong thnh phn ha hc canc cho thy du hiu nhim ngun nc.

23. Sunfat

Sunfat thng c mt trong nc l do qu trnh oxy ha cc cht hu c ccha sunfua hoc do nhim t ngun nc thi ngnh dt nhum, thucda, luyn kim, sn xut giy. Nc nhim phn thng cha hm lngsunfat cao.

nng sunfat 200mg/l nc c v cht, hm lng cao hn c th gybnh tiu chy.Tiu chun nc ung quy nh sunfat nh hn 250 mg/l.

24. Florua

Nc mt thng c hm lng flo thp khong 0,2 mg/l. i vi ncngm, khi chy qua cc tng vi, dolomit, t st, hm lng flo trongnc c th cao n 8 9 mg/l.


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Kt qu nghin cu cho thy khi hm lng flo t 2 mg/l lm en rng.Nu s dng thng xuyn ngun nc c hm lng Flo cao hn 4 mg/l cth lm mc xng. Flo khng c biu hingy ung th. Tiu chun ncung quy nh hm lng flo trong khong 0,7 1,5 mg/l.

25. Xyanua

Xyanua c mt trong ngun nc do nhim t cc loi nc thi ngnhnha, xi m, luyn kim, ha cht, si tng hp.

Xyanua rt c, thng tn cng cc c quan nh phi, da, ng tiu ha.Tiu chun nc ung v nc sch u quy nh hm lng xuanua nhhn 0,07 mg/l.

26. Coliform

Vi khun Coliform (ph bin l Escherichia Coli) thng c trong h tiuha ca ngi. S pht hin vi khun Coli cho thy ngun nc c duhiu nhim.

Tiu chun nc ung v nc sch u quy nh hm lng E. Coliformbng 0. Ring Coliform tng s trong nc sch c cho php 50 vi khun

/ 100 ml.

Phn 3Kt lun

Qua qu trnh thc hin bo co,nhm rt ra cnhiu vn quan tm trong nc gii kht nh cclai ng ha hc trong nc gii kht cng nhbenzeoat v CO2 c mt trong sn phm ny.


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Nc gii kht l mt s la chn nhanh chng trongx hi hin i. Tuy nhin ng qu lm dng ccsn phm ny.

Vi nhng phn trnh by trn,mong cc nh u t sn xut thc hin nhm em li mt sn phm tt cht lng v an tan khng ch cho ngi Vit mcn c cc quc gia.

Bn cnh li khuyn y bi bo co ca nhm gp

phn vo vc chia s mt phn kin thc trong snphm nc gii kht. Nhng do thi gian cn hn chv kin thc cn hn hp nn vic mc li l khngth trnh khi mong cc c gi b qua cho.

Ti liu tham kho:

_TCVN 5042: 1994.

_V nhiu ngun khc trn internet.


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