Ô Nhiem Moi Truong Boi Thach Tin (Asen)_Le Van Khe

8/14/2019 Nhiem Moi Truong Boi Thach Tin (Asen)_Le Van Khe

1/19


2/19

VN NHIM MI TRNG BITHCH TN (ASEN)

CC NI DUNG CHNH: I) Gii thiu v thch tn(Asen).

II) Cc nguyn nhn gy ra s nhim c thch tn (asen)trong t v nc ngm.

III) Tc hi ca thch tn(Asen) n sc kho ca con ngi.

IV) Cc phng php phng nga v x l loi b thch tn

(Asen) trong mi trng b nhim.


3/19

I)Gii thiu v thch tn(Asen).1)Thch tn (Asen) l g?

Asen l tn Vit gi nguyn t s 33 lngbng tun hon Men--l-p, tn Anh l Arsenic.Nguyn t Asen c k hiu l As.

Thch tn l tn gi thng thng ch nguyn tasen, nhng cng ng thi dng ch hp cht xitca asen ha tr III (As2O3).xit ny mu trng,dng bt, tan c trong nc, c gp 4 ln thyngn. Khi ung phi mt lng thch tn bng naht ng, ngi ta c th cht ngay tc khc .

Hinh1. Cu t Asen


4/19

2)S phn b ca Asen trong t nhin. -Asen l thnh phn t nhin ca v tri t, c mt khong 1 n 2 mg asen/kgt. Mt s qung cha nhiu asen nh l pyrit, manhezit,... Trong cc qung ny,asen tn ti dng hp cht vi lu hunh rt kh tan trong nc nh:asenopyrit(FeAsS), realgar(AsS), orpiment(As2S3).

-Asen c trong cc : hm lng Asen trong cc magma t 0.5-2.8ppm, cc carbonat 2.0ppm, thp hn trong cc trm tch 6.6ppm(A.P Vinogradov,1962).Trong cc phin st phn ln Asen tn ti trong silicat(85.5-92.5%). phn nh cnli dng hp cht khc nh xit sulfur, asenua khang(7-14.5%).

- Asen c trong khng kh: hm lng Asen c trong khng kh thng rt nhtrung bnh khong 5 ng/m3 trn th gii, vng nhim trung bnh khong 15ng/m3.


5/19

-Asen trong t v nc ngm: Theo iu tra ca UNICEF, asen c trong tt c t,, cc trm tch c hnh thnh t nghn nm trc ti Vit Nam, vi nng khc nhaub thoi ho ngm vao trong t v thm nhp qu trnh cu thnh cc t hp hu c haythm thu vo mi b mt c t st, cht kt ta hay cht hu c trong nc ngm. Do ,hm lng ca thch tn (asen) c trong t v nc ngm l tu thuc vo cu to ia cht

ca tVit Nam c nhiu ni b nhim arsen v l quc gia th hai trn th gii, sau

Bangladesh. Quan st bn nhim arsen c th thy, Bc B, hu ht cc tnh pha Namsng Hng nh H Ni, Vnh Phc, H Ty (c)(ng Ho, an Phng, Thanh Oai, Hoic, Phc Th ), Hng Yn, H Nam, Nam nh, Ninh Bnh u b nhim arsen vi

nng cao. Ring Thanh Ha th c thng ngun ln h ngun sng M u b nhimnng. Nam B th Lm ng, ng Thp, An Giang cng c hm lng arsen trongnc ang mc bo ng,


6/19

II)Cc nguyn nhn gy ra s nhim c thch tn(asen) trong t v ncngm.

Ngun thch tn(Asen) nhim trong mi trng t v nc ch yu l do cc qutrnh t nhin v c bit l hot ng nhn sinh.

1) Cc qu trnh t nhin.

-Thch tn hnh thnh trong t t s thoi ho ca cc loi v khong vt cha n.

- S phun tro ni la, hot ng magma, nhit dch s lm phn tn Asen vot.S xm nhp ca asen vo nc ngm ch yu l do s ha tan ca asen sn c tronglng t, ha tan cht khong, qung v s n mn ni.

-Thch tn c th thm nhp qu trnh cu thnh cc t hp hu c hay thm thu vomi b mt c t st, cht kt ta hay cht hu c.

- nhng vng ng bng c ph sa bi tch th nc ngm thng nhim thch tn.nhng ht As khng tan trong ph sa s b kh t As5+(khng tan) thnh As3+ (tan trongnc) trong mi trng ym kh do vi sinh vt to ra.


7/19

2) Hot ng nhn sinh.- Vic khoang ging nc khng hp l hoc cc cuc khai

thc m c th lm cho Asen tch t trong t ho tan vo trongnc ngm

- t nhin liu ho thch,t rc, nu chy qung, luyn kimkhai thc v ch bin qung nht l qung sulfur v asenua, snxut v s dng thuc tr su dit c, phn ho hc, v kh hohc.

Nga trc y vic t than lm nhit nng thi vokhng kh khong 3000 tnAs/nm. Trong nng nghip, s dngphn bn, thuc bo v thc vt cha As, thc y As phn tnvo mi trng nc v trm tch.


8/19

3) Tc hi ca thch tn(Asen) n sc kho ca con ngi.-Asen l mt cht rt c, c gp 4 ln thu ngn. Hm lng asen trong

nc sinh hot phi < 0,01 mg/l(Tiu chun ca T chc Y T Th Gii (WHO))mi l t yu cu. Theo T chc Y t th gii WHO c 10.000 ngi th c 6

ngi b ung th do s dng nc n c nng asen > 0,01 mg/l nc. i viTCVN, hm luong As trong nc sinh hot < 0.05mgAs/lit.

-Asen khng gy mi v kh chu khi c mt trong nc ngay c lng lm cht ngi, nn khng th pht hin bng cm quan.

Ngi dn s b nhim c thch tn khi s dng ngun nc b nhim As vi

hm lng vt qu tiu chuan cho php(TCVN l 0.05mgAs/L). Asen xmnhp vo c th ngi ch yu qua ng n ung, h hp, qua da hoc truyn tm sang con


9/19


10/19

-Bnh sng ho da thng xut hin tay, chn, lngbn tay, gan bn chn - phn c th c xt nhiu hoctip xc nh sng nhiu lu ngy s to thnh cc inhcng mu trng gy au n. Bnh en v rng mngchn c th dn n hoi t, rng dn tng t ngnchn.

-Tnh trng nhim c asen lu ngy cn c th gyung th (gan, phi, bng quang v thn) hoc vimrng, khp, gy bnh tim mch, cao huyt p.

-Asen lm thay i cn bng h thng enzim ca cth, lm bin i gen tr em.Phn ln nhng gene nyc xu hng kt hp vi cc qu trnh vim nhim catr, trong tng lai s khin tr tng nguy c mc cccn bnh ung th.

Hinh2. Bn tay b nhim thch tn


11/19

Theo kho st ca LHQ th cc bnh nh dch t, AIDS hay ccbnh ly nhim khc th s ca ly nhim cao nht ch khong 60triu ngi/nm, nhng mi nm trn th gii c 140 triu ca nhimc arsen. Chnh v th, ngi ta v thc trng ng c arsen lv ng c th k. V s ly nhim ca thch tn ln c th con

ngi c cc nh khoa hc cn gi asen l st th v hnh.


12/19

III) Cc phng php phng nga vx l loi b Thch tn (Asen) trongmi trng b nhim.

--Cc gia nh s dng nc gingkhoan nn x l bng phng php sckh, gin ma, bn lng, lc...va khst, va loi b c asen trong nc.

Hinh3. Dn ma oxi ho st v Asen.


13/19

-Loc nc b nhim thch tnbng ti lc. Askhok Gadgil(ngiLawrence Berkeley) vcc cng s khm ph ra rng

trong tro than c cha cht ferrichydroxide v y l mt cht ckh nng hp thu thch tn.


14/19

-Phng php loi b hp chtAsen hu c acid diphenylarsenic(l(CTHH:C6H5)2 AsOOH; y l thchtn hu c cc c (c th gy ri lontm thn), khng b thoi ho sinh hcv c th sn sinh ra cc cht c khc

qua cc bin thi ho hc v nhit.)ca(AIST) ti Nht.Dng dung dch cc loi cn, c

bit la methanol pha vi khong 3-5%acid photphoric c th trung ho c100% thch tn hu c, ngay c khinng thch tn trong t cao ti

3.570 mg/kg.

Hinh 4.t v ngun nc Nht b nhim thchtn do v kh ho hc thi chin tranh.


15/19


16/19

- D nc nhim thch tn bng vi khun pht sang: li dng khnng nhy cm vi As ca vi khun Escherichia coli bin igen sao cho chng pht sang khi d thy As trong nc.

- p dng cng ngh nano: Dng mt khong dng gi st,Fe3O4

hay cn gi l magnetite, nghin thnh bt tinh th mn n kch thc


17/19

KT LUN

Cc qu trnh t nhin nh qu trnh nhit dch to qung sulfur, phun tro nila, s thoi ho t , kh cc hidroxit st cha As, oxi ho khong vt sulfurcha As trong trm tch v cc hot ng nhn sinh lm cho hm lng As ctrong nc ngm ngy cng cao, vt qu mc gii hn cho php l 0.05mg/lit(TCVN).

Hin nay nhiu ngi dn ang sng trong tnh trng nc sinh hot b nhimthch tn e do n sc kho ca hang triu ngi dn trong c nc. t bit li vi ngi dn cc tnh min bc, H Ni, H Ty , Hng Yn c hmlng thch tn rt cao vt qu tiu chun cho php cua VN. V vy, cc cquan chc nng cn tin hnh nghin cu ton din v a ho mi trngAs(ngun gc, hnh vi tp trung, phn tn, trong cc hp phn mi trng, hin

trng v xu th nhim cng vi nhng tc ng ca n n sc kho cngng v cc bin php phng nga, bo v mi trng.), lm c s khoa hccho vic hn ch v loi tr nhim trong pham vi khu vc v ton lnh th VitNam.


18/19

Ti Liu

1)Nhn Dn (10/08/2006)2)Theo tui tr3)(http://vuongtron.vn/UserFiles/Image/2_TinTuc/1_SKvDS/Arsen/480_1.gif)4)www.nea.gov.vn5) TRNG S 1994. nh gi o65 nhim bn v xut cc bin php bo

v ngun nc di t mt s khu vc trng im thuc ng bng bc b.LTC.H Ni.6) www.google.com.vn
http://vuongtron.vn/UserFiles/Image/2_TinTuc/1_SKvDS/Arsen/480_1.gifhttp://www.google.com.vn/http://www.google.com.vn/http://vuongtron.vn/UserFiles/Image/2_TinTuc/1_SKvDS/Arsen/480_1.gif


19/19

CHN THNH CM N!

Documents

Ô Nhiem Moi Truong Boi Thach Tin (Asen)_Le Van Khe