TAP CHI HOA HOC T 51(1)22 27 THANG 2 N A M 2013 NGHIEN CU''''U PHAN TICH VA DANH GIA DU" LU''''CNG MOT S6 CHAT 6 NHî ivi Hi/u c a T6N LU''''U & VUNG CCPA SONG CON, QU^ SON, QUANG NAM Tran Thi Van Thi*, Lc Tli[.]
TAP CHI HOA HOC T 51(1)22-27 THANG N A M 2013 NGHIEN CU'U PHAN TICH VA DANH GIA DU" LU'CNG MOT S6 CHAT NHi^ivi Hi/u c a T N LU'U & VUNG CCPA SONG CON, QU^ SON, QUANG NAM Tran Thi Van Thi*, Lc Tlii My Hanh, Lc Trung Hieu Khoa Hod hgc trudng Dai hgc Khoa hpc Hue Dfin Toa soan 24-5-2012 Abstract The concentrations of organochlorine pesticides and PCBs were determined in surface sediments, river water collected from the Con river and its estuary Soil samples were also collected at the storage area and surrounding areas were analysed lo determine the residual levels of persistent organochlorine compounds Results obtained show that the concentration of organochlorine pesticides (OCPs) in sediments for DDTs ranged from to 6.8 ng/g; for cyclodienes fi-om 5.0 to 10.1 ng/g, for PCBs from 14.2 to 104.8 ng/g The concentrations of the DDTs, PCBs, cyclodienes and HCHs in soil samples ranged from to 1351.3; 3.9 to 7114 2; to 1377.3 and 20.9 ng/g, respectively Keywords: Organochlorine pesticide residues, PCBs, simultaneous analysis, gas chromatography GIOI THIEU Cac chat nhiem hUu co khd phan hiiy (POPs)bao gdm cac thudc trir sau ca d o (OCPs) sir dun;g ndng nghiep va cac hgp chat PCB (PCBs) sir dyng cdng nghiep - cd anh hudng ldn ddi vdi sue khde ciia ngudi, da dang sinh hgc va mdi trudng sdng [1, 10] Sau dugc sir dung, cac hgp chat van tiep luc tdn luu qua hang chuc nam va gay anh hudng lieu cue ddi vdi mdi trudng Nhieu cong trinh nghien ciru da tien hanh phan lich ddng thdi cac thudc trir sau ca cio va cac PCB cac nen mau khac nhu nudc, dat, tram tich, sinh vat [6] Viec phan lich ddng thdi cac hgp chat vira don gian hda dugc quy trinh phan tich, vira liet kiem dugc thdi gian, chi phi so vdi phan tich tirng loai hgp chat rieng biet [1] Tren dia ban huyen Que San, tinh Quang Nam hien cdn tdn tai tngt kho thudc bao ve thuc vat cd kha nang phat tan cac hgp chat ca cio Tren dia ban huyen cdn cd khu cdng nghiep Ddng Que San cd dien tich 600 ha, cum cdng nghiep Que Cudng cd dien tich 40 ha, cum cdng nghiep thj Iran Ddng Phii cd dien tich 50 Toan huyen cd khoang 631 ca sd san xuat cdng nghiep va tieu thu cdng nghiep nhung viec xir ly nudc thai chua dugc quan tam dung muc, nudc thai chua qua xu ly da thai true tiep moi trudng [2] Cho tdi nay, chua cd cdng trinh nao nghien ciru ve van de Vi vay, viec phan tich va danh gia du lugng cac chk nhilm hiru ca ton luu d viing cira sdng Con, Que Son, Quang Nam la cap thiet de cap nhat thdng tin ve mdi trudng THU'C NGHIEM 2.1 Lay mau va chuan bj mau Mau dugc lay vao miia xuan 12 thang nam 2012 Tdng sd mau ISy bao gdm mau nudc, mau tram tich va mau dat Trong dd, mlu nudc va mau tram tich dugc ISy tai ciing tga dg Mlu d5t tai kho tdn trii' la mau Id hgp dugc lay tir vj tri kho, cac mau dat khac la cac mau don lay tai cac vi tri da xac djnh Vj tri lay mlu dugc th6 hien d hinh 2.2 Hoa chat Chuin PCBs gom ddng lo^i (PCB 28, 52,101, 138, 153, 180); chuan dan le ciia thuoc trir sau co cio bao gdm: p.p'-DDE, p,p'-DDD, p,p'-DDT, aHCH, y-HCH, S-HCH, Dieldrin, Endrin, Heptachbr; chat ddng hanh trich lorobenzen; chat ngi chuan pentachloronitrobenzen Hda chat tinh khi8t (Merck): axeton; etyl axetat; mudi khan Na2S04 (nung d 450°C gid) va NaCI (ho^t hda d 250''C gid), Florisil (hoat hda d I80°C 12 gid, roi bao quan binh hut km), H2SO4, n-hexan (Han Qude): cat phan doan vdi cgt dai 0,8 m, thu d 68°C K£t qua phan tich GC/ECD cua «-hexan sau da chung cat cho dudng n8n on dinh TCHH, T 51(1), 2013 2.3 Chiet va Iam sach mau 2.3.1 Chiit mdu [1] Mlu nudc sau Igc dugc tien hanh chiet IdngIdng bang dung mdi «-hexan Mlu nudc (Hit) dugc n-hexan, mdi Ian chiet vdi ti I? thi tich nudc: nhexan la 10:1 (v/v) Sau dd lam khan dung mdi chiet bang each cho qua phSu Igc cd chua Na2S04 khan Mlu dat (trim tich) dugc dem chiet bing h? thong soxhlet Them 100 ng/mL chit dong hanh vao 10 g mau, chiet bing hdn hgp /i-hexan/etyl axetat (3/2, v/v) 120 mL, thdi gian 12 gid 2.3.2 Lam sgch vd Idm giau mdu Mau chiet dugc lam giau ve 2-5 mL tren thiet bi cd quay Dich chiet cd d^c dugc xir ly bang H2SO4 dgm dac va tiep tyc rira bing nudc cat den khdng cdn axit nita Sau dd xir ly bing phoi ddng da dugc ho^t hda de lo^i cac hgp chat luu huynh Cot chiet pha ran florisil (1 g) dugc su dyng de lam sach dich chiet Sau chuan b] xong cot florisil, toan bg dich chiet dugc chuySn len cgt, rira giai cdt vdi 70 mL hdn hgp H-hexan/axeton 2%, toe dg rua giai 4-5 mL/phiit Djch rua giai dugc cat quay giam ap d 40-5D°C ve the tich 1-2 mL va sau dd dugc chuyen vao dng thuy tinh 10 mL vdi mgt lugng nhd hexan Djch tiep tuc dugc cd dudi dung mdi bang ddng nita, them chat ndi chuan pentachloronitrobenzen (PCNB) va dinh muc dSn the tich I mL de phan tich bang he thdng sac ky GCECD [2] 2.4 Quy trinh phan tich Vi?c phan tich ham lugng OCPs va PCBs dugc thyc hi?n tren thiet bi phan tich GC-ECD (Agilent 7890A) t&i Trung tam Ky thuat Tieu chuIn Do ludng Chat lugng II - Thanh phd Da Ning (mgt sd mau dugc th\rc hi^n tren thiet bi GC-MS) Cgt mao quan DB-5MS (30mx0,32 mmx0,25 ^m) vdi tdc dg ddng N2 la 12 psi (2,0904 mL/min) Nhiet injector va detector lan lugt la 270°C, 300°C Chuang trinh nhiet dg GC tang tir 120^0 den 170°C vdi tdc dg nang nhiet 4°C/phiit va thdi gian giu 15 phut; sau dd !en tdi 180°C vdi toe l°C/phiit, thdi gian gift phut; cudi ciing len 240*'C, tdc dg °C/phut, nhiet dugc giu' phut He thong GC hoat dgng theo ch8 dg chia ddng (5:1), ^L mlu duge tiem vao he thdng GC 6h phan tich dinh lugng tdng OCP va tdng PCB PCNB dugc sir dung lam chit ngi chuan [4, 5] Phan tich djnh Iugng tong OCP va tdng PCB sir dung phuang phap ngi chuan Dudng chuan ciia cac Tran Th} Van Thi vd cgng sic chat chuan dugc xay dyng vdi h? sd tuang quan Idn (R > 0,997) Ham lugng tong PCB se dugc tinh bing tong cua PCB dong loai nhan vdi he sd 4,81 - gia trj tuang duang quy cho hdn hgp Arochlor 1254 [I] Gidi ban phan tich dinh lugng cua phuang phap (MDL) vdi tong OCP tir 5,72 den 21,02 Mg/L ddi vdi mau nudc; vdi tong PCB tir 9,56 din 44,62 ^ig/L ddi vdi mau nudc KET QUA vA T H A O LUAN 3.1 Ket qua phan tich OCP va PCB cac mau moi trudng Vdi quy trinh phan tich da chgn, chiing tdi tiln hanh phan tich OCP, PCB mau nudc, trim tich va dat tai huy?n Que San Ket qua phan tich du lugng OCP va PCB cac mlu dugc the hien d bang Doi vdi mau nudc: Nl, N2, N4, N5 (phan tich bang GC-MS) deu khdng phat hien dugc, rieng mau N3 (phan tich bang GC-ECD) cd ham lugng heptachlor (47,11 ng/L) chua vugt muc cho phep theo QCVN 08:2008 cua Bg Tai nguyen va Mdi trudng la 0,05 |,ig/L Ndng dp cac chat can phan tich mau dat tai kho tdn trir cd du lugng hgp chat ca c\o rat ldn ca kit qua GC-ECD va GCMS, vugt muc gidi han cho phep theo QCVN 04:2008 cua Bg Tai nguyen va Mdi trudng la 0,01 mg/kg Ham lugng DDT, PCB len din hang tram, hang ngan ng/g, dIu la ngudn phat thai cac hgp chit CO cto va PCB nghiem trgng cac khu vyc xung quanh Mau dat tai cac viing ian can kho tdn tri~r cd ham lugng chit d nhilm khdng Idn nhu tai kho tin trij Diiu cho thly, su phat thai Iheo dudng tham thau va lan truyen dat rat cham chap (thudng la dac diem ciia loai dat tai vimg khao sat), gan kho tdn trir lai ngui thay miii hda chat, Vdi dieu kien h^u ndng nhu d Quang Nam, cd the viec phat thai cac chat hiru ca de bay hai theo dudng khuech tan khdng lai thay rd hon sir phat thai cudn trdi hay tham thau qua dat Cac mau tram tich deu phat hien cac chat nhung vdi ham lugng ihlp Chung tdi nhan thay tram lich d day chii yeu la cat sdi nen khdng cd kha nang luu giir cac chat ca cio phat tan tir kho tdn tru Nhin chung, ham lugng cac hgp chat nghien ciiu mau dat giam dan theo thii tu tdng PCB (77,50%) > tdng DDT (20,41%) > tdng cyclodiene (1,86%) > tdng HCH (0,23%) Theo nhilu tac gia, ap suat hai cua HCH cao ban DDT nen tdc bay hoi nhanh hon DDT, phan hiiy nhanh ban dat dudi tac dyng cua enzym, dan den du lugng cua HCH dat thudng thap hon DDT mac dii HCH dugc sir dung lam thudc trir sau nhieu han DDT [7] Nghien ciru phdn tich va danh gid TCHH, T.51(I), 2013 Bdng I Nong dp cac chat phan tich cac mlu dat va tram tich Nong dg mlu, ng/L H