Tiiu ban Sinh thai, Moi tncdng vd qudn ly Bien ^ 177
BIEN DONG TICH TU KIM LOAI NANG TRONG M O T SO LOAI RONG
Nguyen Binh Thuat, Biii Minh Ly, D^ing Xuan Cirdng, Lam Thu Ngan, Le Nhu* Hau Vien Nghien cdu va iTng dung cdng nghe Nha Trang,
02 Hiing Vuong - Nha Trang - Khanh Hda Email: ngdinhthiiat(5).nitra.ac.vn
O nhiim kim logi ndng da tdng len trong nhicng thdp ky gdn day vd da trd thdnh mgt vdn de quan trgng trong cdc co quan qudn ly mdi trudng. Asen, cadimi, thiiy ngdn vd chi ndm trong so cdc nguyen tS vi luong co dnh hudng Idn vd cd cdc nguy co cao nhdt ddi vdi sice khde con ngudi Muc dich cua nghien cieundy Id theo doi sv tich luy Cd, Pb, Hg vd As trong mgt sd mdu rong thu thdp tie cdc viing ven bien Khdnh Hda. Do do. chiing toi quan tdm din (1) xdc dinh phgm vi ndng do kim logi nang trong cdc lodi rong biin d Khdnh Hda, (2) md td theo thdi gian su biin doi cua nong dg kim logi ndng trong cdc lodi rong bien. Mdu dugc thu gom vdo thdng 3, 4, 5 trong cdc ndm 2009, 2010, 2011. Thdnh phdn chi, asen, thity ngdn vd cadimi dugc xdc dinh trong 7 lodi rong phd biin tgi vimg bien Khdnh Hda. Hdm luong cua cdc kim logi (mg/kg kho) dugc tim thdy ndm trong khodng gidi han: Pb (0,02-0,46), As (0,03- 22.91), Hg (0,02-0,59) vd Cd(0.03-1,16).
Abstract
CHANGES IN HEAVY METAL ACCUMULATION (Cd, Pb, Hg and As) OF THE SEAWEEDS
Pollution from heavy metals has increased in recent decades and has become an important concern for environmental agencies. Arsenic, cadmium, mercury and lead are among the trace elements that have the greatest impact and carry the highest risk to human health. The aim of the present study is to compare the accumulation ofCd, Pb, Hg and As in the seaweeds collected from the coast of Khanh Hoa. Because of that, we were interested to (1) determine the concentration range of heavy metals in seaweed species in Khanh Hoa: (2) describe the temporal variation of heavy metal concentrations in the seaweeds.
Seasonal collections were done in March, April, May 2009, 2010, 2011. Lead, arsenic, mercury and cadmium contents were determined in 7 species of seaweed in Khanh Hoa. The concentration ranges found, expressed in mg/kg dry weight, were: Pb (0.02-0.46) As (0.03-22.91), Hg (0.02-0.59) and Cd (0.03-1.16).
Keywords: lead; cadmium; arsenic; mercury; seaweed
178 /fp/ nghi Khoa hgc vd Cdng nghj biin loan qudc lan thic V
I. MO DAU
Rong biin tir lau da dugc biet den la mdt thanh phan quan trpng trong he sinh thdi ven bd. Nd la nai cu tni va la ngudn thuc an cho cac sinh vat bien va ban than rong bien la noi tich tu cac khoang chit, cac kim loai da lugng va vi lugn^ cd trong nude bien, trong do As, Cd, Pb, Hg la cac nguyen td vi lugng mang tinh dgc td dugc hap thu cd trong rong biin. Tir vai chuc nam lai day cac nha khoa hpc da khang dinh dgc tinh ciia nguyen td As phu thudc vao trang thai hda tri va dang iien ket hiJu co hoac vd co ciia nd [5]. Ham lugng Cd cho phep cd mat trong rong biin dimg lam thuc pham nam trong khoang tir 0,1 den 3ppm tiiy thudc vao quy djnh cua moi nude [4]. Ham lugng cho phep cua Pb trong rong bien lam thyc phim cho ngudi chip nhan tai Nhat la 0,9ppm. Ham lugng cho phep ciia Hg trong rong biin diing lam thuc phim chap nhan tai Nhat la 0,5ppm [9]. Hien nay, san phSm tir cac loai rong bien dugc su dung nhu thuc an bd dudng cao cap dugc ua chuong nhieu d cac nude Au, M^ [1]. Trong y dugc rong bien la ddi tugng cd chda nhieu hgp chat cd hoat tinh sinh hgc cd tiem nang ling dung trong linh vyc dugc hgc [2].
Trong tieu chuan dang ky cdc san pham che bien tir rong bien sir dung trong y dugc, thyc pham cac kim loai Cd, Pb, As, Hg ludn la cac chi tieu quan trpng dugc de cap den. O Viet Nam, van de xac djnh cac kim loai nang dpc hai da dugc quan tam nghien cuu tir nhieu nam trudc, viec nghien cuu cd y nghia ve sy thay ddi ham lugng kim loai nang theo thdi gian tir cac mau rong bien trong sudt thdi ky sinh trudng. Ngoai ra, thdng qua ket qua nay cd the danh gia che do dinh dudng cua nhieu loai ddng vat an rong cd the anh hudng den sire khde cua chiing. Qua viec xac djnh ham lugng cac kim logi trong cac mau rong cd the kiem soat su anh hudng ciia cac kim loai tir cac san pham su dyng nguyen lieu rong bien.
IL PHirONG PHAP VA NGUYEN LIEU
Quang phd hip thy nguyen tOr Id graphit (QPHTNT-LG) tir lau la phuang phap dugc sir dung rdng rai de xac djnh ham lugng cac nguyen td kim loai trong cac mau y hoc, sinh hpc, dugc pham, thyc pham nhd cd dd nhay cao d mure ppb. Mdt loat cac cai tiln Idn ve thiet bi nhu su dung he tfiong bd chinh nIn, cac chit cai biin hda hoc da lam giam thilu va loai trir cacylu td anh hudng do cac loai iihilu nhu nhilu hda hgc, nhieu do ion hoa, nhieu nen, nhieu phat xa, nhilu phd; hip thy nIn hay hip phu khdng chpn lpc nen phuong phap QPHTNT-LG la mpt cdng_ cy hihi ich dl djnh lugng As, Cd, Hg va Pb trong cac mau y sinh hpc, dugc pham, thuc pham va mdi trudng [8].
Thiet bi
May quang phd hip thy nguyen tu Thermo Elemental-Model Solaar M6 Dual Zeeman Atomic Absorption Spectrometer, thilt bj tiem miu ty ddng FS95, den catot rdng HCL data eroded, dugc dieu khien bing may tinh vdi phan mem dieu khiln Solar Version 27. Cac che dp do quang phd dugc dan ra trong bang 1.1 va 1.2, sir dung hieu ung hi?u chinh nen Zeeman.
Tieu ban Sinh Ihai, Moi mr&ti^ va quan ly Bien 179 Bans I. Cdc dieu kien do quang pho hap thu nguyen tir sir diing lo graphit logi
"PyrolyticaUy Coaled Electrographite "[11]
Thong so As Cd Hg Pb
X(nm) Dp rpng khe (nm)
Thoi gian do (s) Kieu do Dong den (%)
193,7 0,5
3 Dien tich
90
228.8 0,5
3 Dien tich
50
253,7 0,5
3 Dien tich
90
217,0 0,5
3 Dien tich
90 Bcm^ 2. Chicmig trinh nhiet do cita. Id graphit sic dung logi "PyrolyticaUy Coaled
Electrographite "[11]
Nguyfin
Biroc Nhiet do ( ° C ) '
Thdi gian luu(s)
Tdc do gia Luu lugng khi nhiet (°C/s) (L/phut) As
Cd
Hg
Pb
Say kho Tro hoa Nguyen tu lioa
Lam sach 16 Say kho Tro hoa Nguyen tir hoa
Lam sach 16 Say kho Tro hoa Nguyen tir hoa
Lam sach 16 Say kho Tro hoa Nguyen tir hoa
Lam sach 16 100 1.200 2.600 2.700 100 800 1.200 2.500 100 200 750 2.500
100 800 1.200 2.500
30 20 3 3 30 20 3 3 30 20 3 3 30 20 3 3
10 150
0 0 10 150
0 0 10 150 0 0 10 150 0 0
0,2 0,2 0 0,2 0,2 0,2 0 0,2 0,2 0,2 0 0,2 0,2 0,2 0 0,2
180 Hpi nghj Khoa hoc va Cong nghe biin todn quoc lan thir V Hoa chat
- HNO3 nong do 70% (Merck); chuin As lg/1 pH3 (Fluka); chuAn Cd lg/1 (Fluka);
chuin Pb lg/1 (Fluka);'chuin Hg lg/1 (Fluka); Pd lg/1 (Fluka); Mg IgA (Fluka); Ni lg/1 (Fluka); nuoc sieu sach; Pd(N03)2 sir dung lam chit cai bien hoa hoc cho 2 nguySn to Kg va Cd, Ni(N03)2 sir dung lam chat cai biSn hoa hpc cho As va Mg(N03)2 sir dung lam chat cai biin hoa hpc cho Pb; argon 99,9% tir Xi nghifp Hod ky nghe Nha Trang; chuin 10"', 10"^ 10"', 10"*, 10"^ (g/1) ciia cac nguyen t6 Cd, Pb, Hg, As dirge chuin bj tir cac dung dich g6c ban diu lg/1 voi nuac sieu sach.
Can 0,5g mlu kho vao trong binh pha mlu dung tich 55ml dua vao do 5ml axit nitric, day nip lai va van chat (moment luc 2,3Nm), chay v6i chuang trinh nhiet dp nhu 6 bang 1.3.
Bane 3. Chuang Irinh nhiet dp ciia Id vi song
Stage
0)
Cdng suat eye dai (W)
1200
% Cdng suat 100 (So binh >20)
Toe do gia nhiet (phut)
20
Nhiet do ("C) 200
Thai gian giir nhiet (phut)
30 NguySn lieu
Rong biin thupc 3 nganh rong luc, rong dd, rong nau dugc thu thap tir sdng C^i, Ddng Bd, Sdng Ciu, Hdn Chdng, Hdn Dd ciia 7 loai rong vao cac thang 3, 4, 5 ciia cac nam2009,2010,2011.
Bdng 4. Ten khoa hgc, tin mdu, vi tri vd ngdnh cua cdc mdu rong nghiin ciru TT
1 2 3 4 5 6 7
Ten khoa hpc Ulva lactuca Ulva reticulata G. tenuistipitata
G. bailiniea Sargasum serratum
S. oligocystum Turbinaria ornata
Ten mau I II III IV V VI VII
Nganh Rong luc Rong luc Rong do Rong do Rong nau Rong nSu Rong nau
Vftrithumlu Song Cai Song Cai D6ng B6 Song ciu Hon Chong
Song Cai Hon Do
Tiiu ban Sinh thdi, Moi tncdng vd qudn ly Bien 181
III. KfeT QUA VA THAO LUAN
Bans 5. Hdm luong cdc kim logi biin dgng theo thdi gian cua 7 lodi rong
Mau
1
II
III
IV
V
VI
VII
Trung binh nam 2009 Ham lugng ((ig/g) Cd
0,07
0.14
0,49
0,28
0,27
0,3<
0,58 Pb
Ktt
0,06
0,07
0,38
0,07
0,07
0,24 Hg
0,10
0,09
Ktt
Ktt
0,31
0,05
0,10 As
0,36
0,33
4,23
0,19
12,9 5
14,1 0
14,4 0
Trung binh nam 2010 Ham lupng (^g/g) Cd
0,08
0,15
0,47
0,25
0,25
0,37
0,52 Pb
Ktt
0,06
0,08
0,34
0,05
0,06
0,14 Hg
0,09
0,09
Ktt
Ktt
0,27
0,06
0,09 As
0,38
0,36
3,95
0,18
11,8 5
14,1 0
13,4 5
Nam 2011 Thang
3 4 5 TB
3 4 5 TB
3 4 5 TB
3 4 5 TB
3 4 5 TB
3 4 5 TB
3 4 5 TB
Ham luong (ng/g) Cd
0,07 0,07 0,09 0,08 0,03 0,26 0,15 0,15 0,05 1,16 0,06 0,42 0,24 0,29 0,19 0,24 0,36 0,32 0,05 0,24 0,30 0,46 0,51 0,32 0,35 0,55 0,55 0,48
Pb Ktt Ktt Ktt Ktt, Ktt 0,05 0,12 0,06 0,02 0,04 0,16 0,07 0,16 0,46 0,33 0,32 0,05 0,07 0,03 0,05 0,03 0,11 0,08 0,07 0,26 0,19 0,08 0,18
Hg Ktt 0,08 0,24 0,11 0,12 0,07 0,07 0,09 Ktt Ktt Ktt Ktt Ktt Ktt Ktt Ktt Ktt 0,59 0,09 0,23 Ktt 0,04 0,10 0,05 0,13 0,09 0,02 0,08
As 0,47 0,45 0,32 0,41 0,53 0,24 0,15 0,31 0,03 0,11 11,22 3,79 0,16 0,16 0,17 0,16 13,98 10,04 9,27 11,10 5,57 11,13 22,91 13,20 18,10 10,59 10,12 12,94 Qua bang 5 ta nhan thay Cd va As
thay trong rong Ulva lactuca. Rieng Hg
1 diu cd trong hiu het cac loai rong, Pb khong tim trong hai rong G. Tenuistipitata va G. bailiniea
182 //p; nghj Khoa hgc vd Cdng nghe biin todn quoc Idn line V
khdng tim thiy. Riosmena-Rodriguez R. cho rang qua trinh tich liiy kim loai nSng d moi loai sinh vat tiiy theo nhu ciu trong qua trinh phat trien, mdi trudng ty nhien cd the anh hudng cac sinh vat dac biet la sinh vat nhay cam nhu rong bien [13]. Ham lugng cac kim loai trong cac mlu rong nhin chung trong 3 nam it cd sy thay ddi Idn, vi vay chiing tdi dua sd lieu cac thang gin day nhit cua nSm 2011 cac loai rong de thao luan.
Nguyen td Cd cd ham lugng thap nhat 0,03pg/g d rong Ulva reticulata vao thang 3 va cao nhat la 0,55pg/g d rong Turbinaria ornata vao thang 4, 5. So sanh vdi loai rong V.
Rigida (Canakkale, Turkey) nhan thay Cd cd ham lugng cao nhat vao miia he 0,05(j,g/g va thap nhit vao miia thu 0,001pg/g. [10]. Griselda Margarita Rodriguez-Figueroa da khao sat loai rong Padina diirvillaei va nhan thay rang ham lugng Cd thap nhat la l,45pg/g vao thang 5 va cao nhit vao thang 6 dat din 9,lpg/g [7].
Ham lugng Pb rong G. Bailiniea cd ham lugng cao nhat vao thang 4 dat 0,46pg/g va thap nhat d thang 3 dat 0,16|ig/g. Rddenas de la Rocha S. ham lugng Pb cao nhat la mSu rong thu tai Nhat Ban len den 0,85|j,g/g va thap nhat la tai Phap vdi ham lugng 0,31iig/g [14]. Rong Sargasum serratum va S. Oligocystum hap thu kim loai cao nhat vao thang 4, Griselda Margarita Rodriguez-Figueroa khao sal rong Padina durvillaei nhan thay ham lugng Pb thap nhat la l,5^tg/g vao thang 8 va cao nhat vao thang 5 dat den 30|ig/g [7].
Qua bangl nhan thay ham lugng Hg cao nhat la 0,59fig/g ddi vdi rong Sargasum serratum vao thang 4 va thap nhat 1^ 0,02|ig/g vao thang 5 ddi vdi rong Turbinaria ornata.
Ddi vdi Hg cac tai lieu dac biet quan tam khi nd tdn tai trong thyc phim dudi dang vo co hay hihi ca va ham lugng cd vugt nguong cho phep ddi vdi an toan thyc phim [6].
Ham lugng As cua loai rong Ulva reticulata la 0,9iig/g thu thap vao thang 5/2007 so sanh vdi mau dang khao sat cd thip hon nhung van nam cimg ngudng [12]. Ham lugng As cua mau rong do tai thdi diem thu miu phan tich cao han muc cao nhit cua loSi rong Porphyra [14]. Ham lugrig As cao nhit hip thu d loai rong S. Oligocystum dat 22,91pg/g vao thang 5 va thdp nhdt cung d loai rong nay la 5,57pg/g vao thang 3. Rddenas de la Rocha S. khao sat ham lugng As trong rong Laminaria ong nhan thdy ham lugng As cao nhat la miu rong thu tai Phap len din 53,lpg/g va thip nhit la tai Tay Ban Nha vdi ham lugng 30,l^g/g, cdn Han Qudc ham lugng As dat 40,0^g/g nim giiia hai gia tri tren [14].
IV. KET LUAN
Da xac djnh ham lugng cac kim loai Cd, Pb, Hg va As biin ddng theo thdi gian trong mpt sd loai rong. Nhin chung su tich tu cac kim loai d mot sd loai rong nghien cuu neu so sanh vdi cac loai rong ciing loai tren thi gidi cd thi ndi rong biin ciia ta tich tu thip kim loai nay nhung ddi vdi kim loai khac thi cd the cao han va tiiy thupc vao loai rong.
Nhirng ket qua nghien ciru ve hien trang han lugng cac kim loai Cd, Pb, Hg va As trong rong bien bien ddng theo thdi gian d bai nay chi la nhGng thdng tin ban diu. D I cd thi kit l u ^ va cd each nhin tdng quan va toan dien han cin nghien cuu bd sung them so lieu vl mdi truang nude noi rong sinh trudng phat trien va cac dpng vat ton tai noi dy su dung rong bien nhu la nguon thirc an trong qua trinh phat triin ciia chiing.
Tiiu ban Sinh thdi, Moi tricdng vd qudn ly Bien
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{\0\. Mehtap Ustunada, Hiiseyin Erdugan, Selehatlin Yilmaz, Riza Akgul, Veysel Aysel, Seasonal concentrations of some heavy metals (Cd, Pb, Zn, and Cu) in Ulva rigida J.
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[12]. Nguyin Dinh Thuit. Nghien cdu phan tich lien tuc (on-line) d ^ g Asen trong mdt sd ddi tugng mdi trudng biin bing phuong phap lien hgp sic ky Idng va hip thy nguyen tu. Luan an Tiln sy Hda hpc. ViSn Hda hpc. Vien Khoa hpc va Cdng nghe Viet Nam.
Ha Ndi 2009.
[13]. Riosmena-Rodriguez R., A. Talavera-Saenz, B. Acosta-Vargas, S. C. Gardner, Heavy metals dynamics in seaweeds and seagrasses in Bahia Magdalena, B.C.S., Mexico, 2010, J. Appl Phycol, 22,283-291.
[14]. Rodenas de la Rocha S., F.J. Sanchez-Muniz, M. Gomez-Juaristi, M.T. Larrea Marin, 2009, Trace elements determination in edible seaweeds by an optimized and validated ICP-MS method. Journal of Food Composition and Analysis, 22, 330-336.
Ngudi dgc nliQn xet: TS. Nguyin Dire Cu
