Ô nhiễm arsenic trong nước ngầm huyện thanh bình và tân hồng, tỉnh đồng tháp

TAP CIJ PIAT TRIEN KHKCN, TAP 18, SO M l • Z015 O nhiim arsenic nuac ng§m huyen Thanh Binh va Tan Hong, tinh D6ng Thap T o T h i Hien D Thj Thuy Quyen Tnjffng Oai hoc Khoa hoc T y nhien, DHQG-HCM Brittany Merola • Avner Vengosh TrLTong Dai hoc Duke, Hoa Ky 7J-/7 r {Bai nhgn ihdng nam 201J nhdn dang J ihdng 12 ndm 2014) TOM T A T Tdng cdng 55 mdu nw&c ngdm dd (tmng binh 182.2 mV) As phdn bd khdng dwoc thu thdp thdng vd thang ndm diu trdn toan khu vwc nghidn ciru Ndng 2012 nhdm xde dinh hidn trang d nhiim As As nw&c ngim ting ndng huydn Thanh nw&c ngdm tai huyen Thanh Binh vd Binh vwat xa gi&i han cho phdp cOa WHO vd Tdn Hdng tinh Ddng Thdp, Vidt Nam Nghien QCVN 01:2009/BYT cCni da tiin hdnh dae thdng sd hien tmng binh Id 408.16 pg/L Ngwqrc l$i, 100% (pH, nhidt dd, DO, EC, Eh) vd ldy miu nw&c tai Tdn Hdng cd ndng dd nhd han tnjong mdu phdn tich As vd Fe tdng sd Kit qud gi&i h$n cho phdp Id 10 pg/L v&i gid tn Ndng dd Fe cd twang eho thdy tinh chit nw&e ngdm ting ndng tai quan am y nghTa vol ndng dd As cdc Thanh Binh vd Tdn Hdng cd sw khde biet ro mdu nw&c Si/ khw hda tan oxyhydroxide ret cd thi id CO chi quan gidi phdng As Tdng chCra nw&c ndng Thanh Binh a diiu kien khir (trung binh -93 mV) trong nw&c ngdm tdng ndng huydn didu Iddn oxy hda chiim wu thi tai Tdn Hdng Binh sit Thanh TLF khda: arsenic Ddng Thap, nw&e ngim, CO ehi giai phdng MCf&kV Nhifim dpc su dung nudc ngam bj fi nhifim As dupc xem Id vu nhilm dflc hing loat Ifin nhdt frong ljch su loii ngudi nfiu xet vfi sfi lupng ngudi bj dnh huong Ddng bdng Ganges Brahmaputra (Bangladesh) vd Bengal (An Dp) la nhinig vimg bj dnh hudng nghifim frpng nhat voi hon 63 fripu ddn phoi nhifim vdi ngudn nudc ngdm cd ham Iupng As Idn hon 10 yg/L (tifiu chudn nudc udng ciia WHO) v i hon trifiu trudng hpp cfi fripu chdng bfinh arsenicosis, ung thu da nhiim dfic As mdn linh [1] Nhihig die difim dia chdt tuong ddng ciia c i c dfing bdng chdu tho l^i Vipt Nam so sinh vdi ddng bdng Ganges I^i Bangladesh d i thu hut sy quan ldm eua c i c nhd khoa hpc tCr nhihig ndm 2000 Nhifiu nghifin cuu dd phil hifin van dfi fi nhifim As nghifim frong vd dua Viet Nam len fren bdn dfi fi nhifim As the gidi Ddng luu y, nhung khu vuc cfi bifiu hifin d nhiem As lai la nai tap trung dfing ddn cu va l i viing sdn xudt nong nghiep chinh ciia nuoc ta, do nhu cdu su dyng nudc ngdm cho sinh boat vd nfing nghiep Id rat ldn Vific su dyng ngufin nudc nhifim As frong thdi gian ddi sfi dan loi nhttng hau qua nghiem frpng khdng chi cho ngudi ddn frong khu vyc md cdn dnh huong den sue khde cpng dong As di vio chuoi thirc dn frong qud frinh sin xuit nfing nghifip Sy nhifim dfic As dupc gpi Id TraiB 73 SclMCCftTecliiloii BtvilBpieil, Vol 18, No.M1- 2015 arsenicosis Id mpt tai hpa mfii frufing doi vdi sue khde ngudi Nhihig bifiu hien cua bpnh nhan nhiem dpc As li chting sam da (melanosis), diy bieu bi (kerarosis), t6n thuong m^ch miu, rfii loan cim gidc ve sy di dpng Ngudi bj nhiem dpc As ldu ngdy sS cfi bieu hipn simg hoa da, gdy s^m v4 mat sdc tfi da hay benh Bowen tir dan den hoai tu hay ung Ihu da, viem ring, khdp, tim m^h [2] nudc sach nfin ngufin nudc sinh hojit chu yeu cua ngudi dan li nudc gieng khoan tu nhin Cac mau nudc dupc lay tir nhi/ng tang chda nudc d dfi sdu nhfi hem 80 m (Holocene vi Pleistocene) day Ii dfii tupng khai thdc chu yfiu ciia ngufii ddn Tfing s6 mdu ciia nghien ciru Id 55 mau Idy t^i cdc gilng d hp gia dinh (hlnh 1) Trong dd cfi 34 gi^ng thufie huyfn Thanh Binh CO dp sau tir 12 - 60 m thupc phirc hfi chira nudc Holocene vd Pleistocene dupc ldy ngau Theo kfit qua dieu tra frfin cd nudc cua Lien dodn Quy ho^ch v i Dieu tra Tii Nguyen Nudc mi^n Nam vd tfi chuc UNICEF T?i Vipt Nam, n6ng dp As cao nudc ngdm dupc phdt hi^n I^i khu vyc chii yfiu Id Dfing bdng Sfing Hfing v i Dong bdng Sfing Cdu Long [3] T?i dflng bing sfing Hfing, cdc nghifin cim vfi As frong nudc ngdm dd dupc frifin khai tir rat sdm vdi mdc dp chi tiet cao [4, 5, 6] frong dfi nhihig nghien cdu tai khu vyc Dfing bing Sdng Cdu Long cdn nhieu ban chfi Nghien cuu ndy cung cap thfing tin chi tifit v l tinh chdl nudc ngdm v i lim rfi co che giii phdng As frong nudc ngam tai khu vyc nghien ciru Ihu^c tinh Dflng Thdp, noi co bifiu hifin As frong nudc ngam cao nhit I^ii Dfing bdng Sfing Ciiu Long [7], Ngodi ra, kfit qud cua nghifin ciiu sfi Id nhihig thdng tin qu-y gid phyc vu cho vipc phdt frifin cfing ngh^ xu ly nudc ngim thich hpp t^i khu vyc nhifin frong difn tich nghifin cuu 10 km x 20 km, Tit c i cac gieng deu ndm rit gin sdng vdi khoang each frung binh nho han km 21 mau nudc lay t?i cic gifing thu§c huyfin Tdn Hfing d^u cdch xa song Tiln vfii khoang each frung binh Id gieng dfin sfing Id 15 km Trfin difn tich nghifin cdu rpng 10 km x 15 km I^ii huyfn Tdn Hfing, 23 mau nudc thu^c ting Pleistocene d dO sdu tir 15 73 m dd dupc thu Ihiip Phinmg phdp l&y mdu, thong s6 M^n tnrdng Thfing tin dp sau v i tpa d$ dja \^ dupc ghi nhdn lai moi gieng Bam xd gilng khodng 15 phiit dfi fin dinh nfing dp oxy hda tan frong nudc frudc tiln hdnh cic thfing sfi hifin frudng v i lay mau Ndm thfing so nhiel d$, pH, dfi dSn, the oxy hda v i oxy hda tan duoc xic djnh lEii hifn frudng vdi cdc ihifil bj c i m tay (Bang 1) cung cip nhieu thdng tin vfi tinh chit nudc ngim Nudc PHirONG PHAP NGHIEN CUU gieng dupc Ipc nhanh qua mang Ipc 0.45 pm v i Khu vfrc nghiin cAu chiia frong lp Naglene 60 mL Idm bdng nhya Nghifin cdu dupc thuc hipn tai Iinh Dong Thip vio tfldng vd thing ndm 2012 Hai khu vyc nghien cuu cu thfi Id cii lao huy^n Thanh Binh v i thi fran Sa Rii tfiufic trung Iam huyfn Tin Hfing Thanh Binh li vimg frpng difim sin xuit luong Ihyc cua Iinh Dfing Thdp, vimg cii lao thufie huyfin Thanh Binh chii yfiu sir dung nudc ngim cho ho^I dfing nfing nghipp Tan Hfing li huyfin vimg sdu, gidp bien gidi Campuchia, cdch xa sfing Tiln v i chua cd mang ludi cung cip Trail 74 HDPE (High Density Polyethylene) vd ndp vdn Idm tir nhya polypropylene chuyfin diing cho liy miu nudc, bio quin bdng 100 jiL HN03 ddm die Mau dupc bdo qudn d nhiet df phdng vd chuyfin den phdng thi nghifm Earth and Ocean Sciences, Dai hpc Duke, Hoa KJ' dfi phdn Uch Nfing dp As vd Fe dupc phdn tich bdng phuang phdp Khfii ghfip cdp cam dng cao tin ICPMS (Inductively Specfrometry Coupled Plasma Mass TAr cii PUT TIIEIHSCN, TAP 18, S I Ml - 2015 Hinh Khu vyc nghien cuu huyfn Thanh Bhih va Tan Hong, tinh E)6ng Tliap (khoanh Iron) Bang I Ten Ihifil bi thong sfi hifin Irudng Ten thilt bj H i n g san \uix Thdng so Oxi I970i WTW(Dirc) Oxy h6a tan (DO) LFI I Schott (DiJc) Nhift dp D$dan(EC) pH pHlOO YSI (USA) Eco»nse The oxy hoa (Eh) Cdc ihdng so hifn tnrdfng vd kit qud phdn tfch tgi phong th{nghi$m Bdng Cdc Ihdng sd hifn trufing tai hai khu vyc nghifin cuu TSn H^ng Tbanh Binh Trung binh Khoang gia tn Trung binh Khoang gia trj 7.0 6.7-7.7 6.1 8-6.6 Nbif t dO •c 29.5 28.7-30.6 29.8 293-302 EC ^S/cm 1311 382 - 3 1540 304.2-3035 DO mgn 21 0.7-4.0 U2 02-3.7 Eh mV ^3 -139-149 182.2 60-261 pH Trui 75 Science & Tecbiology Developneni, Vol 18, No.MI- 2D1S KET QUA VA THAO LUAN Phdn ldn cac mau nudc cd pH thupc khodng QCVN OI:2009/BYT nhifin deu dupc xfip gid frj gin frung tinh ctia nudc ngam thfing vio logi nudc ciing G i i frj dp cung cua nudc thudng (6 - 8.5) C i c mdu nuorc lai huyfn Tdn ngim tdng nfing huyfn Thanh Binh cd phdn cao Hflng cfi gid Iri pH tucmg ddi thip hon so vdi hon so vdi Tan Hfing Thfim vao dd, frong ion huyen Thanh Binh Gid in nhift dp khong cfi sy S04"', c r vd Na"^ tai Thanh Binh rit thip v i hodn chfinh Ifch ddng kfi gitta hai khu vuc nghifin cCru toin ndm frong khodng gia fri cho phep dfii vdi Gia In dfi din (EC) ciia cic mdu nudc Thanh nudc dn uflng theo QCVN 01:2009/BYT tfii cic Binh dao dpng tir 382.6 din 6330 ^S/cm Tuy mdu nudc Idy tai Tan Hdng co gid frj khd cao vd nhifin, 70% sfi miu cd EC thdp ban 1000 pS/cm mflt sd mdu vupl lifiu chudn cho phep Cic miu nudc d huyfin Tdn Hdng cfi gii fri dfi Ndng d^ As nirdc ngam dan tuong doi lap trung Cfi dfin % cdc miu nudc d Tan Hfing cd EC Idn hon 1000 pS/cm As phdn bd khfing dfiu tai hai khu vyc nghien Gii fri DO cua cic mau nudc d khu vuc nghifin cdu (Hinh 2) d huyfn Tdn Hfing, nong dp As cim cfi khodng dao dfing tucmg tu nhung DO cua lit cd cic mdu nudc tang nfing dfiu thap cic m§u nude d Tin Hfing cfi phin thdp hon han gidi h^in cho phep ciia WHO vd QCVN 50% sfi mdu I^ii Tdn Hdng cd DO nhfi han 01:2009/BVT Id 10 pg/L, dao dpng lir k.p.h den mg/L so vdi 10% tai Thanh Binh Cfi sy khic bift 8.91 yg/L, vdi gid frj trung binh Id 2.63 pg/L ding chil y vfi gid frj Eh gifla hai khu vyc nghifin Trong dd, nudc ngim tdng ndng d huyfn cim Hdu hfit gifing tdng nfing (32/34 gifing) thufie Thanh Binh l^i co bieu hifin fi nhiem As nghifim huyen Thanh Binh cfi Eh dm dao dfing Id -139 frpng vdi 94% sfl mau nudc vupt xa tifiu chuin mV dfin -28 mV Nhu vdy dilu kien khu chifm cho phep N6ng dp As bifin dflng khoang ttr uu the frong cdc ling chda nudc nfing huyfin 3.22 dfin 981.43 yg/L, gii trj trung binh li 408.16 Thanh Binh Nguoc lai difiu kifn oxy hda chifim Hg/L, gip 40 lin so vdi miic an todn la 10 pg/L uu thl frong nudc ngdm ting nfing huyfn Tdn Nghifin cuu quan tdm den ting chua nudc nong Hfing vdi gii fri Eh dao dpng Iu 60 - 261 mV, tai tinh Dflng Thap vi ddy Id dfii tupng khai thdc trung binh Ii 182.2 mV Sy khic d ddc chu yfiu cua nguoi ddn Cdc mdu nudc dupc Idy difim ndy cfi mfii tuong quan chat chfi vdi nfing tai cdc gifing cd dfi sdu td 12-73 m Dfi sdu tuong dp As tai hai khu vyc nghifin cuu sfi duoc thdo Cmg vdi phiic hf luan d nhihig myc sau v i Tdn Hfing cfi thinh phin hda hpc tuong dfii khde N6ng dp HCO3" t^i Thanh Binh cao gap lan so vdi Tdn Hfing, difiu ndy cung phu hpp vdi kfil qui pH lai hifn frudng Nudc ngim d c i hai khu vyc nghifin ciiu dfiu cfi dfi ciing khd cao chua nudc Holocene vd Pleistocene Xet den khu vyc cfi vin dfi nhiem Bdng cho thdy nudc ngim tai Thanh Binh As irong nudc ngim la huyfin Thanh Binh thi As cd mdt d til cd cdc mdu nudc d dp sdu khde D i e bift la cdc gieng d dfi sdu tir 10-40 m cfi nfing dp As cao bit thuong, gdp 100 lin so vdi gidi ban cho phep cua As frong nudc Tuy van thdp hon gid fri cho phep- theo Bang Ket qud Thdng s^ phdn tich mdu nuflrc Thanh Binh lii TSn Hgng (n=34) D^sftu Trail 78 m {n=2l) Trung binh Tmng vt Khoang Trong binh Trung v| Khoang 29 23 12-60 36 39 15-73 TAF Cri PUT I E I I H O T«P IS, SO Ml - 2015 0$cn- 300 213 295 CsCOA HCOj H^T so.=- n ^ 431 429 111-780 193 158 1.6 kpb-I9.6 109 67 88-334 4-2% 250 ^ •ngft 33.8 19.5 2.9-160 267 233 21-742 250 Nl rag/L 51 49 10-112 238 207 30-554 200 c» n^/L 77 76 24-158 34 24 5-71 «B ma/L 25 26 7-52 31 25 7.6-78 Fc mg/L 4.45 4.43 0J6-12_5S 0.4 0_!5