1
1. Khi qut v nh gi ri ro:
1.1 Gii thiu v nh gi ri ro:
1.1.1 Mt s khi nim v ri ro mi trng: nh ngha chnh thc ca ri ro l:
t hp ca xc sut xy ra mt s kin khng mong mun v h qu - kt qu ca s kin
khng mong mun trn
Ri ro = Xc sut * H qu
Ri ro nn ( background risk) l ri ro c th gp phi khi cha k n s
hin din ca nhn t gy ri ro c bit ang xt y la ri ro c sn.
Ri ro tng thm ( incremental risk) l ri ro bi cc ngun khc t them
vo hay do nhn t c bit gy ra;
Ri ro tng cng ( total risk) l tng ri ro nn v ri ro tng thm.nh gi
ri ro (RM) l tin trnh nghin cu, tm kim c lng kh nng xy ra cc nh hng
bt li t s phi nhim ca ngi/ s vt vi s hin din ca cc yu t ha hc, sinh
hc tn ti trong mi trng ( Harris R, and et.al ..,1991)1.1.2 Mc ch ca
nh gi ri ro:
nh gi ri ro c mc ch c lng mi nguy hi n sckhe con ngi v mi trng.
RM c vai tr quan trng khi a ra quyt nh v khc phc nhim bng cch xc nh
mt mc ri ro bng con s c th chp nhn c ri nh ra mc nhim s to ra mc ri
ro c th chp nhn .
RM l cng c c hiu qu, gip cc nh qun l ti nguyn v mi trng a ra cc
quyt nh hp l nhm ngn nga, gim thiu v loi tr cc tc ng c hi gy ra i
vi con ngi, mi trng v x hi ni chung, ng thi m bo sn xut hp l.
RM cn cung cp cc gii php sau:
Xc nh cc trng hp nguy him tn ti tim nng ri ro
Cung cp tin trnh nh gi v ti liu ha mi e da
nh gi tim nng mi nguy hi
Xc nh mi lin h kch c v mc ca nhng trng hp c ri ro khc nhau, xc
nh cc u tin la chn cn thit
Xc nh chin lc hnh ng ng c th, cung cp cho nh qun l nhng thng tin
cn thit1.1.3 Phn loi nh gi ri ro mi trng:
Ri ro i vi sc khe cng ng
Ri ro i vi cc ngun ti nguyn thin nhin
Ri ro do s pht trin kinh t
Ri ro do thin tai
Ri ro do pht trin cng ngh v sn phm mi
1.2 Tnh hnh nghin cu v nh gi ri ro trong nc
Phng php RMT v ang c p dng rng ri v ph bin nc ta. RMDB ( nh gi
ri ro mi trng d bo) vng ven b Nng l cng trnh u tin c trin khai v
cch tip cn phng php RM c thc hin bi nhm chuyn gia a ngnh ti a phng
di s tham vn ca cc chuyn gia ca chng trnh hp tc khu vc trong Qun l
mi trng cc Bin ng Nam . Khun kh ca d n c xy dng vi mc ch nng cao
nng lc ca a phng trong qun l mi trng v ti nguyn vng ven b, to c s
hon thin chng trnh quan trc mi trng v cc k hoch, quy nh v qun l ti
nguyn v mi trng lin quan.Phng php RM p dng cho nh gi ri ro thuc bo
v thc vt thng qua cc ch s tc ng mi trng trong sn xut sp l tnh Hi
Dng. D n ny tp trung iu tra 120 nng dn trng sp l c s dng thuc bo v
thc vt do nhu cu thm canh tng v tng sn lng sn xut. S dng thuc bo v
thc vt khng ng s to ra nhiu ri ro cho con ngi v mi trng. Phng php
ny s dng ch s EIQ ( environmental Impact Quotient) ph bin trong nh
gi ri ro thuc bo v thc vt v n phn nh s lng v v cht trong qu trnh s
dng thuc. Mc ch ca nghin cu l nh gi c tnh hnh s dng thuc bo v thc
vt v tnh ton c ch s tc ng v cc nhn t nh hng ti cc ch s trong qu
trnh sn xut sp l ca nng dn. T ra bin php gim thiu nh hng ca thuc bo
v thc vt.1.3 La chn ch : nh gi ri ro bi chon lp rc thi sinh hot
huyn Tn Chu _ Tnh Ty Ninh Tnh cp thit ca ti:
ngha ca ti:
2. Phng php nghin cu:2.1 Phng php ma trn ri ro
(Copy bi hm ba ca mnh)
2.2 Phng php phn tch cy sai lm
- L phng php gip chng ta xc nh c s lin kt, s ko theo sai lm ca
cc hin tng, cc hin tng ny c th dn n nhng mi nguy hi cc tai nn ..ng
thi cy sai lm gip cho ta xc nh r con ng i trong sut qu trnh hnh
thnh cc nguyn nhn sai st. Ngoi ra, cy sai lm cn gip chng ta xc nh c
cc mi quan h gia cc nguyn nhn khc nhau v m hnh phn tch cy sai lm l
nn tng c bn phn tch nguyn nhn v hu qu. 2.3 Phng php phn tch cy s
kin
Cy s kin l trch ra t mt nhnh cy sai lm. y l phng php lit k tt c
cc hin tng sp xy ra hoc theo s la chn. Cy s kin c s dng ph bin cho
nhng qu trnh phc tp chia thnh nhiu mc an ton khc nhau hoc cho nhng
trng hp khn cp khc nhau. V th thc hin phng php phn tch cy s kin
chng ta cn phn tch nhng hin tng ban u, cc ch th biu hin, xc nh cc
lp cc tng bo v v sau xc nh cc s c , ri ro, li ch v s thnh cngPhn
tch cy s kin da trn c bn l phn tch hu qu ca s vic.
V d minh ha cho phn tch cy sai lm cy s kin:
2.4 Phng php nh gi ri ro bn nh lng
Phng php c bit n the quotient l mt phng php ph bin nht m t c tnh
ri ro bn nh lng. Phng php ny ch yu tnh t l ( hoc thng s) biu th cho
nng mi trng d bo ( PEC) c chia bi mt nng d bo ngng (PNEC) tnh ton
thng s ri ro (Risk Quotient)
Trong
PEC : Nng mi trng d bo
PNEC : Nng ngng d boKhi RQ=1 ri ro cao.3. Kt qu nghin cu3.1 Nhn
din mi nguy hi
3.1.1 Xc nh chi tit mi nguy hi a im vi cc i tng trong iu kin bi
chn lp ang hot ng ( Phng php ma trn nh gi ri ro nguy hi ) ( Xy dng
s liu minh ha sau) a. Xy dng ma trn mi nguy hi a im:
Xy dng ma trn mi nguy hi a im l xc nh cc mi nguy hi xy ra trong
khu vc nghin cu tng ng vi tng a im c th ti khu vc nghin cu . Bng
4.1 di y m t cc mi nguy hi gy ra do nc r rc v kh bi rc i vi 5 a im
c th ca bi chn lp Ty Ninh l: trm cn rc, khu tip nhn x bn, h chn rc
v cc h cha nc en.
b. Phn loi mc nghim trng
Cn c vo mc tc ng ln c th ngi c th lp ra thang phn loi mc nghim
trng. T bng phn loi ny kt hp vi tn sut phi nhim l c s xc nh mc ri
ro do cc mi nguy hi gy ra.c. Phn loi nguyn nhn tc ngDa vo bng 4.1 v
4.2 c th lp ra bng phn loi nguyn nhn tc ng. Nhiu mi nguy hi pht
sinh t bi chn lp s l nguyn nhn gy ra nhng bt n ln c th ngi. V d: cc
mi nguy hi ca bi chn lp nh chy n, kh c hay ngt th c th gy t vong
cho con ngi.
d. Lp thang nh gi tn sut phi nhimCn c vo iu kin thc t ti bi chn
lp ang hot ng, c th xc nh c tn sut phi nhim ca cc i tng c lin quan
i vi tng a im c th ca bi chn lp.
e. Lp ma trn ri roCn c vo mc nghim trng tc ng ln ngi v tn sut
tip xc i vi cc mi nguy hi s c xc nh c mc ri ro nh trnh by bng 4.6
di y. Ri ro = Tn sut*hu qu
f. Thuyt minh ri roQua cc bng phn tch trnh by trn, c th xc nh c
mc ri ro cho tng i tng ty theo tn sut tip xc ca i tng vi cc mi nguy
hi. Sau y l thuyt minh v mc ri ro cho cc i tng lin quan.
nh gi ri ro i vi nhn vin li xe rc nh gi ri ro i vi ngi nht rc nh
gi ri ro i vi nhn vin vn phng
nh gi ri ro i vi c dn xung quanh
nh gi ri ro i vi ngi i ng
3.1.2 p dng phng php nh gi ri ro bn nh lng
V d: qui trnh xc nh cc tc ng i vi i tng trong nh gi ri ro nhim t
nc thi cng nghip n ti nguyn nc ngm c trnh by:
Hnh: S nh gi ngng cc nng EC50 l nng nh hng n 50% sinh vt th
nghim. H s ri ro trong trng hp ny c tnh:
Trong
PEC : Nng mi trng d bo
PNEC : Nng ngng d bonh gi ri ro ban u cht lng nc ngm i vi sc khe
con ngi3.2 Xc nh nguyn nhn hu qu nguy hi ca bi chn lp rc tnh Ty
Ninh bng phng php cy sai lm (FTA) v cy s kin (ETA)
xc nh mi nguy hi ca bi chn lp Tnh Ty Ninh, trong nh gi ri ro mi
trng c rt nhiu phng php nh: phn tch iu hnh v nguy hi, phn tch cc
kiu hng hc v tc ng, phn tch khn cp v nhng tc ng ca cc kiu hng hc,
phng php bn sinh thi, s nguyn nhn hu qu, phng php phn tch cy s kin
(Event tree analysis - ETA), phng php phn tch cy sai lm (Fault tree
analysis FTA). Trong khun kh lun vn ny, chn phng php phn tch cy sai
lm (FTA) v cy s kin (ETA) xc nh nguyn nhn v hu qu nguy hi ca bi chn
lp rc tnh Ty Ninh v y l phng php n gin, d hiu v ph hp vi iu kin Vit
Nam.
Mu nc thi
c im ha l: (PEC)
- COD.
- Kim loi nng:As, Cr, Cu, Pb, Hg, Ni, Zn.
- TN, TP.
c im vi sinh vt (MC)
- Tng Coliform.
PEC > PNEC
MC >
PNEC
Tim nng ri ro i vi H Sinh Thi
ng
ng
