Xây dựng bộ chỉ thị môi trường cho thành phố thái bình, tỉnh thái bình

njg | i va Tai nguyen Mdi trutrng Thira Thicn Hue Hoi Dja ly Vicl Nam Xay dirng bo chi thj moi tru'd'ng cho phd Thai Binh, tinh Thai Binh Doan Thi Ticn', Le Trinh Hai', Pham Ho»ng Hai^ Abstract Environmental indicators are a useful solution sen'c lo study environment sustainable development indicators will provide necessary information lo help managers send out harmonic socio-economic developmeni plan with ecological environment This article used Delphi method (expeil method) to select 19 indicators belongs to a five-group according lo DPSIR framework Drivers- Pressures- Stale- Impact- Responses Environmenlal indicators express relation middle elements m DPSIR framework affect the province environment which IS a good material lo study sustainable development Key indicators, Delphi, environment, sustainable development Thai Binh province M » A U Thai Binh la mpt tinh thuan ndng dang dan dan chuyen ddi sang xu hudng edng nghiep hda ncn kinh te va khu vuc phd dicn hinh cho su ddt mdi Ngay giai doan dau ciia qua Irinh, hicn trgng moi trudng phd Thai Binh da co cae dau hieu d nhiem nghiem irgng ilicn nay, moi nam cac hogt ddng nhan sinh da thai vao moi irudng khoi lugng chat thai khdng 16 Ba khu cdng nghiep m6i nam thai 38,175 tin chat thai ran, irong dd cd gan ngan tan chat thai ran nguy hgi Ben canli do, benh vien da khoa, benh vien chuyen khoa va trung tam y tc vdi long khdi lupng ehal thai phat sinh han 10 ngan mVthang Luang rac thai ciia clip ihuong mai, nhicu dicm buon ban nhd ciing vdi khoang 180 ngan nhan khau (khu vuc ndi thanh) hang thai lugng rac thai ldn va khoang - 35,000 m^ nudc thai sinh hogt Ngoai ra, vdi mat dp dan sd 4201ng/ km" [10], moi moi trudng phai chira dung 160m' lugng rac thai sinh boat,[8] Lupng chat thai da gay nen cac van de d nhiem rac thai, mdi Irudng nudc, moi trudng khong Bao eao tdng hgp danh gia hicn trgng d nhiem moi trudng khu cdng nghiep thang 3/2009 • cho thiy, ndng dp thai CO, SOi, NOi, NH3, bin va dp dn tai khu vuc khu cdng nghiep vupt ticu chuan cho phep 5937, 5938/2005; Nudc thai tai mpt sd dicin thai tir khu cong nghiep co cac thdng so SS, COD, BOD5, coliform vugt ticu chuan cho phep lir - 10 lan lieu chuan Vict Nam (TCVN) 5945-2005 Kct qua phan tich nudc thai tai cua xa ciia mdt sd doanh nghiep san xuat su ve smh, gach men lgi khu cdng nghiep, cac thdng sd COD, BOD., SS Ascn vuot 20.7; 16; 15.5; 10.4 lin i r V N , 5945-2005 [8] Thyc trgng mdi trudng tren gay anh hudng xau tdi ddi sdng nhan dan, la nguyen nhan dan den nhieu benh dich lay lan cdng ddng rat khc igan chan Ddng thdi tac dgng true licp tdi cae hoal dpng kinh te ciia ngudi dan dja phirang, gay cac thicl hgi ve kinh te Do dd, ddi hdi can cd nhirng giai phap cu the va hap ly de dam bao phat trien ben vung mdi tnrdng va bp chi thi mdi trudng la mgt giai phap huu ich Cac chi thj se cho danh gia idng quan vc •liuc trgng mdi trudng [3] Bd chi thj mdi trudng la mgt cdng cu quan ly moi irudng huu hieu, giiip Klina Dfa ly inrdng Dai hoc Khoa hoc Tie nhien, Dai hoc Quoc gia tia \ 61 Vien DQI ly t'lCn Khoa hoc vd Cong nghe ^'lel ^am ,D!A LY TU NHIEN, T A I NGUYEN THIEN NHIEN VA MOI TRUONG Hoi Bia Iv va Tai nguyen Moi trirdng Thiia Thicn Hui HQi Dja ly Vigt cho dia phuang dinh hudng phat iriln bin virng Song tai dja phuang chua co bp ehi thi moi inri^ rieng phu hpp vdi thyc tiln, ma quan ly mdi trudng dya tren bd chi thj mdi trudng qudc gia da^ hanh Dd la bd chi thi mdi trudng cip qudc gia nen cd quy md qua rdng, cd nhieu diem khdng phd ^ vdi dilu kien thuc tiln tai dja phuang Vi vay, nhu ciu vl bp chi thi phuc vu nghien ciru phat iricn bSi virng la rit cin thilt, gdp vai trd quan trgng sy phat triin ciia dja phuang PHU'ONG PHAP Ngoai cac phuang phap nghien ciru truyin Ihdng nhu dilu tra phdng van, thyc dja, v.v., nghis ciru da sir dung mdt phuang phap hien dgi- Delphi Delphi la phuang phap chii yeu dua tren y kie ciia cac chuyen gia moi ITnh vyc [19] Phuang phap naj; da va dang dugc ap dung rongi^i, Qudc tl va gin day la Viet Nam Delphi dupe dgc trung bdi yeu to quan trpng: [21] Su luang tac va anh hudng theo nhdm Su lap lai phuc tgp hoac sy luan phien ciia cac ban hdi hoac cac khia cgnh khac ciiavii thu thgp cac dir lieu vdi cac cau Ira ldi va su phan hdi theo nhdm thdng ke dugc; Thi hien cac cau tra ldi theo nhdm thdng ke, Phuang phap mang cac uu dilm: (!) Ap dung rdng han, (2) De hiiu, (3) Cd thi tra loi cd eau hdi phuc tgp, (4) Kha nang tri bao mat, (5) Tranh nhilu thao tac, (6) Phat hien nhilu kienlhinj mdi, va (7) It ngudi tham gia.[20] Tai Viet Nam phuang phap cimg da va dang la sy lua chpn mdi eiia cac nha khoa hpclreii cac ITnh vuc khac Tren ITnh vyc kinh tl Delphi da dugc ap dyng danh giacae nhan li anfi hudng, cac ca hdi thach thirc, xay dyng quan diem, phat triin, djnh hudng phat trien va dy baoxu hudng phat triin [5] Ngoai ra, phuang phap cdn duge su dung nhim danh gia vai tro ciia cac yen to nghien ciru tai biln dja chit [11], Va dac biet phuang phap Delphi dupe ap dyng nghiet cuu lua chpn cac chi ihi phat triin bin virng [ 14, 15, 16, 17] va ehi thi danh gia chat lupng nudc [9] Vdi viec ap dung Delphi nghien ciru, cac nha khoa hpc da thu dugc nhiing ket cd dp chinh xai cao Phuang phap Delphi dupe the hien qua phin chinh dudi day 2.1 Xay dung danh sach chi thi dir kicn Dya tren cac tai lieu ve mdi trudng dja phuang, ket qua eua qua trinh khao sat thyc dja, tai H&i ve bp chi thj moi trudng cap qudc gia [1] va theo thdng tu ve xay dung bp chi Ihj mdi trudng ciiabf tai nguyen mdi trudng, danh sach chi thj du kicn dupe de xuat dya tren ca sd md hinh dpng luc-^ lyc- hien trang- tac ddng- dap irng (DPSIR) [2, 7] Cae chi thj dupe xay dung theo nam nhdm: Cac en thi ve dpng tyc (D) phat trien kinh te - xa hdi, cac chi thj ve ap lye (P), cac chi thi ve hien trang (S, mdi trudng, cac chi thj ve tac dpng (I), cac chi thj ve dap irng (R) ciia Nha nudc, xa hpi va nguOiDanh sach dua gdm 29 chi thj thudc nhdm vdi; chi thj ve ddng lyc, chi thi vl ap luc,' chi thj ve hien trang, ehi thj vltac ddngva chi thj dap ung 2.2 Lap phieu xin y kicn chuyen gia Danh sach chi thj dy kiln dupe lap bang hdi philu xin y kien chuyen gia ciiiig^ cau hdi md de chuyen gia dua danh gia ve cac chi thj va y kien khac ciia minh Hdi nghi Khoa hoc Dia ly Todn qudc ldn thu 6; Thdnh phd Hue 9/ H$i Dia 1^ Viyt Nam l-jjpja 1^ vk Tii nguygn MSi trirong Thira Thi£n Hui Theo dgc dilm ciia phuang phap Delphi, cac cau hdi dua phai cd phuang an tra Idi dudi dgng ^lui^g, nen cac chi thj dugc dua danh gia theo nam muc; -1 dilm: tuang iirng vdi mirc dp khdng thi'eh hpp - dilm: tuang irng vdi muc dp it thich hgp - diem: tuang img vdi muc dp thich hgp - dilm: tuang irng vdi mirc thich hgp eao - dilm: tuang irng vdi mirc dp rat thich hgp 23 Lini chon chi thi Cac ehi thj dupe tiln hanh lya chpn theo phuang phap Delphi Cdng tac lya chpn duge ticn hanh theo hai vdng Vdng 1: Phieu xin y kien chuyen gia dugc giii tdi bay chuyen gia gom cac chuyen gia dia ly, • m6i trudng va nha quan ly tgi dia phuang Bay chuyen gia la mot sd gidi han dgi dien cho cac chuyen gia d3 dupe nhieu nghien ciru sii dung nhu Chu va Hwang (2007) [12] Trong thdi gian hai tuan cac chuyen gia se cho danh gia ve muc dg thich hgp ciia cac chi thj mdi trudng dugc de xuat phieu Sau thu hoi phieu, y kien ciia cac chuyen gia dupe thdng ke va tinh loan gia tri trung binh, gia trj tmng vi va dp l^ch tir phan cua mdi chi thj Dya tren y kien ciia cac chuyen gia vdng se cd sy dieu ehinh phieu cho vdng Vdng 2: Phieu xin y kien chuyen gia sau da dieu chinh qua vdng se dugc giri Igi cac chuyen gia de xin y kiln danh gia lan hai cho cac chi thj mdi trudng dd Trong vdng 2, neu mdt chuyen gia khong tham gia tiep thi di^ li^u dd khdng the sir dung vi vgy ddi hdi sy tham gia day dii ciia cac chuyen gia tii vdng 2.4 Xac dinh bo chi thi Sau thu hdi phieu ciia hai vdng phdng van, cac danh gia cho diem cua chuyen gia vdi mdi chi thj dupe nhgp vao excel va dimg cac ham thong ke ttnh toan Tir dd, danh gia muc dp thich hgp cda mdi chi thj Ciic ehi thj mdi trudng dugc lua chpn theo quy tac ciia phuang phap Delphi (bang 1) Bdng I Quy lac phdn tich ddnh gid di lua chgn chi sd sir dung phirang phdp Delphi [12] Vonet Gii tri trung binh (rni,>3.5) Gii trj tmng binh (rm < 3.5) V6ng t + Neu gid trj trung binh (rm,) > 3.5, dp lech tir phan Q < 0.5 va phuang sai (rv,) < 15% thi chi thj i dupe chap nhgn va khdng cin c6 them cac thao lu|in ve chi thj Gi4 tri lmng binh (rm,) > 3.5 hcuC phucmg sai (rv,) > 15% Vom-1 + Neu gia Irj tmng binh (rm,) > 3.5, dg l?ch tir phan Q < 0.5 v4 phucmg sai (rv,) < 15% thi chi thi i dugc chip nhgn vk khong cin c6 them cic thao lugn vl chi thidd N^u gii trj trung binh (rm,) < 3.5, dp lech tii phan > 0.5 vk phuang sai (rv,) < 15% thi chi thj i bi logi bo \k khdng cin cd Ihem cac thao luan ve chi thj B|A LV T U NHIEN, TAI NGUVEN THIEN NHIEN VA MOI TRUONG Hoi Dia ly va Tai nguyen Moi truong Thiia Thicn Hui HOi Dia ly Vicl Nah,r KET QUA 3.1 Vongl ,,' Danh sach 29 chi thj mdi trudng dy kiln dupe dua xin y kiln danh gia tir cae chuyen gia, sanl' vong thu dupe kit qua: 26 chi thi cd gia trj trung binh (nn,) > 3.5, chi thj cd gia trj trung binh (rm,)5 3.5 (bang 2) I 3.2 Vdng ' Kit qua thu dugc la 19 chi thj cd gia trj trung binh (rm,) > 3.5, lech tu phan Q < 0.5 vatil^ thay dii y kiln ciia chuyen gia (rv,) < 15% Theo quy tic phan tich danh gia kit qua ciia phuang phap'' Delphi, sau hai vdng phdng vin chuyen gia ket qua chung duac tdng hpp lai bang i Bdng Tong hgp kit qud sau hai vdng phong vdn [4] Vong ] Gia tn Irung binh (rm,) > 3.5 Kit qua Mat dp dan si (2), ting lupng thai nhilm (4), tong lupng nudc thai Iir cac KCN, khu dan cu (5), T6ng lupng chat thai ran lir cac khu cong nghiep (7), T6ng lugng chit thai y tl (8), Lupng rac Ihai trung binh d cic khu dan cu (9), Ham iugng SO2 trung binh khong (10), Ham lupng NOi khong (11), Ham lupng bui PM,u trung binh nSm (12), Nong bui TSP Irung binh nam (13), Ham lupng CO irong khong (14), Dp due d song chinh (15), Ning dp COD Irong nucrc (16), nfing BOD5 Irong nudc (17), Tdng coliform nudc (18), Dp DO (19), Anh hudng den sire khoe cong dong (20) Thiet hai vl kinh tl (21), Dicn tich cay xanh d6 thi (22), Ty la s6 ca sd san xuat dupe cap giay ehirng nhan ISO 14000 (23), Tong kinh phi thu dupe tir phi bao ve moi trudng (24), Chi phi cho viec bao vfi, cai tao moi Irudng (25), Ty le ho gia dinh dupe sir dung nudc sgch (26), He thong xir l^ nudc Ihai (27), Ty le rac thai dupe Ihu gom va xii ly (28), S6 luong bai ric dupe quy hogch (29) Vong ' jii trj trung binh (rm,) > 3,5, lech tir phan Q < 0.5 va li 16 Ihay ddi y kiln ciia chuyen gia (rv,) < 15% Kit qua 2,4,5,8,9, 10, 11, 12, 13, 14, 18, 19,20,21,22,26,27,28,29 ' Gia tri trung binh | (rm,) < TongdSn so (1), T6ng | so khu cong nghiep (3), Nhu cau niriii: phuc vu sinh hoat,sm ' xuit (6) Gia Iri trung binh (rm,)0,5, , tile thay dii ykiSn cua chuyen gia | (rv,)>l5% 1,3,6,7,15,16,17, 23,24,25 Cac ket qua tren da dugc tinh loan, phan tich tir cac s£ Jiem danh gia cua chuyen gia thdng qua thuat toan thdng ke phan mim Microsoft excel cho kit qua danh gia chinh xac cho tirng cM thi (bang 3) Hot nghi Khoa hoc Dia ly Todn qudc ldn thu 6; Thdnh phd Hue ^/^C H(A Dia Ij' va T^i nguySn Moi trufrng Thij-a Thi e n Hgi Dia ly Vi^t Nam Hue Bdng 3: Phdn lich cdc ddnh gid vdng vd2 [4] T T Chi thi f Tdng dan s6 2 M9S d^ dan sd T i n g s6 khu cong nghifp T6ng lupng ihSi nliifini T6ng lucng nudc ihai iir cac KCN, khu xuiit S Tdng lu(;ng c h k thai y li H ^ Itipng SOj tmng bmh irong khdng 10 11 12 13 14 IS 16 Ham lu(ing NO; khdng Ham lugng CO khdng GiS tn trung Dd l^ch tli phSn Giatnirung binh 2 0,75 29 2 2 2.1 2 2 4 4 4 4 4 4 39 5 2 15 34 5 5 4 5 5 5 05 4,4 4 025 4,1 4 0,5 44 05 43 75 34 4 3,1 4 0,5 28 57 Dg di^c a sdng chinh 4 75 3.9 4 05 4 4 05 Tl 3 4 75 3.9 3 s 4 0.5 36 5 4 4 05 43 5 4 4 025 5 4 4 0,5 43 5 4 4 25 5 4 4 0,5 43 5 4 4 25 5 4 4 05 43 5 4 4 25 5 4 4 0,5 43 5 4 4 25 4 3 4 0.5 37 14 29 14.29 4 5 4 5 Ndng d$ BODi nudc IS Tdng colifonn irong nudc 19 DODO in Anh hudng din sire khoe cijng ddng 05 3,7 0,25 4 4 25 4,1 4 4 0.5 5 4 4 OS 4.1 5 4 4 05 4 5 4 , 25 4.1 3 4 05 37 3 4 05 37 5 4 4 05 39 B|A LY TU NHIEN, TAI NGUYEN THIEN NHIEN VA MOI TRUONG 14.29 14 29 14 29 14 29 14 29 28 57 4 4 N6ng dp COD tiong nudc 17 28 57 5 14 29 14 29 Ndng dp bm TSP trung binh nam Ndng dd bui PMm trung binh nam 3,1 2 42.86 14 29 4 Phuong sai 2B,57 4 5 2 4 Lining rac tliai ining binh is cac khu 3 Nhu c^u nudc phuc vti smh ho^l, san Tdng luijng chdi ihSi ran iCr cac KCN D^nhgiacua chuyen gia Vdng phong 28.57 28.57 14,29 0 H6i Pja ly v^ Tai nguyen Moi triiong ThiJa Thi£n Hue T T Chi thi 21 Thicl hai vekmh tc 22 Difn lich cay xanh dd ihi 23 Ty \i CO sd san xual dupe cap giay chimg nhan 24 Tdng kmh phi thu dugc iCr phf bao v$ mdi tnidng 25 26 Chi phi cho vi£c bao vi, cai t^o MT Ty lc hd gia dinh dugc sir dung nuoc 27 M^ thong xu ly nuoc thai 28 Ty le rSc Ihai dugc thu gom yk xir ly 29 DSnh gi^ cua chuygn gia Vdng phdng Sd lugng bSi rac duoc quy hoach 5 3 HoiDjaly Vigt NJ 4 4 Gi4 U| trung VI Dd lijch IU phSn G i i Iri Irung binh 05 39 4 025 3,9 4 25 5 75 4.1 4 4 v 5 5 5 05 43 5 4 4 05 4,4 5 I 4 2 4 4 4 4 5 4 4 5 5 i 5 5 5 4 5 4 4 0,5 43 5 4 0.25 4 25 4 4 4 4.1 25 43 5 4 4 0,25 4,3 4 4 0,25 43 4 4 0,5 44 5 0,5 46 5 025 47 4 0,25 4 0,5 4.3 PhuJ saiJ ~" i ^ 2i.ir 28,Sji M2» 1429 I4.B cao nhit voi mirc di^tn tnmg binli dat 4.6 va 4.7 sau hai vong phong vin Dieu cho tliay chi Ihi nhan dirge s^ nhit tri va danh gia rat cao cCia cac chuyen gia, ehirng to khu virc nghien cihl, rac thai la vjn d§ cin du(ic quan lam hon nira Trong do, chi thj t6ng dan sa chi dat mijc dilm rll thap tit 2.9 va 2.1 cho hai vong, ngoai ket qua phong vin thiy nhieu sir thay doi y kien cii chuven gia (42.86%) Di6u duoc giai thich la sire ep ciia quy mo dan sd din moi truong s6ng phy thuoc nhieu vao dien tich cua moi trirong Ngjai ra, cac chi thi 2, 4, 5, 8, 9, 10, 11, 12, 13, 14, 18, 19, 21, 22, 27, 29 cung duijc danh giii mirc di'em kha cao hau hit deu tren viSi ti le thay doi y kiSn la 14 29% Day cQng la cac vin de dugt quan tam nghien ciru moi trirong tai khu virc nghien ciru nen dl nhan duoc sir d6ng thuan tit cit chuyen gia Trong so cac chi thj bj loai chi thi tdng sd khu cong nghiep (3), nhu cau nuoc phuc v(i sinh hojl, sail xuat (6) khong dat duoc ca ba chi tieu cua quy tic Delphi Ngoai co cac chi thj tong luong chat thai ran lir cac KCN (7), dp due osong chinh (15), none COD niroc (16), n6ng BOds nircfc (17) deu nhan dugc danh gia cao va khong Co sir chenh l?ch qua Ion \i mirc diem ciia roSt chuyen gia (Q < 0.5) Song ti le thay doi y kiSn ciia cac chuyen gia la Ion hon mirc cho phip > 15% nil b| loai bo Doi voi cac chi thj ty le co so san xuit duoc cip giiy chiimg nhjn (23), tdng kinh plii ll" diroc til phi bao ve moi trucrng (24), chi phi cho vice bao ve, cai tao moi tnrong (25) thi nhi6u chii)* gia cho rang day la cac chi thj rit kho xac djnh va lien quan nhiju toi cac chinh sach bao ve mS iruong ciia nha niroc nen gay sir phan van lira chon Vi vay, y kien ciia cac chuyen gia khongrf sir dong nhat sau hai vong phong van cho kit qua v6 ti le thay doi y kiin la 28,57% >15% , vuot mfe cho phep MOI nghi Khoa hoc £>ia iy Toan qudc idn thu 6; Thanh phdmjn Hui Hgi Dja ly Vigt Nam uftjfljaly v^ Tai nguygn Moi trircrng Thira ThiSn Hue Theo ket qua phan ti'ch a tren thi hau het cac chi thi dua deu duoc danh gia kha cao nhung niih: dp ddng thu^n cho moi chi thi theo danh gia cua cac chuyen gia co nhigu thay d6i la nguyen nhan ehinh khi^n cac chi thi bj loai bo T6ng hgp, phan tich cac danh gia sau hai vong phong van da \\[a chon dirac 19 chi thi t^g sd 29 chi thi dua ra, dap umg du cac yeu cau lira chpn cua quy tac Delphi (bang I) Bdng Bg chi thi mdi Irudng cho ihdnh Thdi Binh [4] Nh6m chi thi Chi thi \h dpng lire (D) Cic chi thj vg dp lire (P) Chi thj Mat dan so Tons luong thai nhiem Tong lirang nuoc thai tir cac KCN, khu dan cu Tons lircmg chat thai y te Lugng ric thai trLng binh is cac khu dan cu Ham luong SO2 trung binh khong Ham lupTig NOl khong H ^ lupng CO khong Cke chi thj vt hign trang (S)' kg kg/ nguai mg/m'' mg/m^ Nong bui TSP tning binh nSm H^m luong bui PMK, irung binh nam T6ng coliform nucrc mg/m' mg/ m' mg/m' MNP/ 100ml Dp DO mg/l Anh huang den siic khoe cpng dong chi thj v^ tdc d$ng Don vi Nguoi/ km^ Tan/ nam Tan/ nSm % Thiet hai v€ kinh Kt Tri?u dong Dien tich cay xanh thi Ty le ho gia dinh duac su dung nuoc sach H? thong xii 1;^ nuoc thai Ty le rac thai duoc thu gom va xii ly m^ (I) C4c chithj ve ddp irng (R) So lugng bSi rkc dugc quy hoach % % BSi THAO LUAN De tien hanh l^a chpn khach the phit hop tiiy theo yeu cau cua moi doi tirgng nghien ciiru dS co nhieu phirong phap dugc sir d^ng Trong do, co hai phuong phap bien nhat la phuong phap phong van (interview), phirong phap danh sach kiem tra (checklist) Danh sach kiem tra (checklist) la mpt phucmg phap dem gian v6i nhieu dang tir cap dO don gian den phirc tap Ve ca ban la de cap den mpt danh sach cac yeu to dugc yeu cau danh gia voi cau tra loi don gian, cho kfit qua phan anh mpt each t6ng hgp vk cong viec dang danh gia Phuang phap don gian, de tiSn hanh, khong c6 han che ve s6 lugng nen su dyng rSt huu I'ch cho qua trinh lua chpn bao gom sS lugng Ion cac yeu t6 Tuy nhien, sir dung phuang phap lira chgn chi thi khong cho ket qua djnh lugng khach quan va thuong khong dCi mii'c thong tin chi tiSt doi vai yeu cau lya chpn.[23] £>1A LY TU NHIEN, TAI NGUYEN THIEN NHIEN VA MOI TRL/ONG Hoi Dja ly va Tai nguyen Moi trirong Thira Thien Hue HoiDjaly VictNimj' Phuang phap phong van (interview) thuc hien phong v4n tryc tiep voi nguoi tra lai dc ihu thgp ' thong tin v^ van dh cSn quan tam thong qua cac cau hoi dugc chuan bj truac va cac cau hoi nia biing '• hai hinh thirc phong van sau (dinh linh) va phong vkn theo phigu (dinh lugng) Phuang phap cung : cap cho chimg ta ca dir lieu djnh lugng va dinh tinh tir nhung ngucxi tham gia Nhung de tien hanh d6i