Treating ballast water with hydroxyl radical on introduced organisms

Chinese Journal of Oceanology and LimnologyVol. 24 No.2, P. 161-167, 2006Treating ballast water with hydroxyl radical on introducedorganisms*ZHANG Zhitao (张芝涛), BAI Mindi (白敏的), XIAO Yu (肖宇),BAI Mindong (白敏冬), YANG Bo (杨波), BAI Xiyao (白希尧)(Key Laborarory of Srong Elecri-field lonizatin Discharge of Liaoning Province; Environmental Engineering Institute,Dalian Maritime Universin, Dalian 116026. China)Received Jan. 26, 2005; revision accepted Sept. 19, 2005AbstractWith physical method of micro-gap gas discharge, a large amount of hydroxyl radical canbe produced in 20th pilot scale system using the ionization of O2 and H2O. In this paper, the effect ofbiochemistry of hydroxyl radicals on introduced organisms in ballast water was experimentally investi-gated. The results indicate that the contents of chlorophyl-a, chlorophyI-b, chlorophy-c and carotenoidare decreased by 35%- 64% within 8.0s and futher to the lowest limit of test 5 minutes. In addition, themain reasons of cell death are the lipid peroxidation, the strong destruction to the monose, amylose, pro-tein, DNA and RNA of cell, and damage in CAT, POD and SOD of antioxidant enzyme system.Key words: hydroxyl radical; introduced organisms; photosynthesis pigment; lipid peroxidation; basiclife substances; antioxidant enzyme; ballast waterAsian kelp Undaria pinnatifida invaded new areas. 1 INTRODUCTIONrapidly, and displaced the native seabed communi-ties (Rigby， 1993). In the Black Sea, the fil-The introduction of invasive marine speciester-feeding North American jellyfish Mnemiopsisinto new environments by ship's ballast water, byleidyi has on occasion reached densities of 1 kg ofattaching to ships' hulls or via other vectors hasbiomass per m2. It has depleted native planktonbeen recognized as one of the four major threats tostocks to such an extent that has contributed to thethe world's oceans by Global Environment Facilitycollapse of entire Black Sea commercial fisheries(GEF). Vessels for world-wide freight shipping(Mackenzie, 1999).In near 20 years, main methods of treatingtransfer about 10 billion tons of ballast water yearly.ballast water are mechanical, physical and chemicalIt is estimated that at least 7 000 different speciesare being carried in ship's ballast tanks around theremoval of species (Bai, 2002). With an open-world. About 110 million plankton specimens areocean-exchange in mechanical removal, only 95 %carried in 1 m' of ballast water. Until today aboutof ballast water was discharged at open-ocean when500 different species are known to have been trans-injecting 3 times seawater to vessels, resulting in theported with ballast water (Geoff, 2000; Mackenzie,problems in safety and high-energy cost (Rigby and1999; Geoff, 2000). As a result, the whole ecosys-Hallegraeff, 1993). By heat treatment in physicaltem is being changed (Hallegraeff and Bolch, 1992;removal, higher temperatures would be required toCarlton, 1994; Holmes and Minchin, 1995; Baideal with thermophilic (heat loving) organisms or2002). In the USA, the European Zebra Musselmon中国煤化工cterial spores. TheDreissena polymorph have infested over 40% of in-YHCNMHGternal waterways and have cost some US$750 mil-* KeyPrject of National Foundaton Kescarch from Science and Tech-lion to 1 billion in control measures between 1989nology, Ministry of China (2002CCC00900), Key and General Projectsand 2000 (Yount, 1990). In southerm Australia, theof NSFC (No.60371035) and Project of Society Development of Dalian(2004B3SF181).162CHIN. J. OCEANOL. LIMNOL, 24(2), 2006Vol.24temperature between 30 and 40C would stimulatemental system of ship's ballast water, the kill eff-the growth of bacteria e.g. Vibrio cholerae (Yount,ciencies of bacteria, mono-algae, protozoan reached1990; Armstrong, 1997). It has to be considered thatalmost 100% within 2.67s when dissolved 0Hchemical removal is a promising method. In 1997,concentration is 0.63 mg/L. Meanwhile the ballastDonald M. Anderson pointed that more than 4 700water quality was improved greatly. In this paper,effective chemical biocides could be used to kill or-the investigations of the biochemistry effects of hy-ganisms in oceans and lakes (Donald, 1997). How-droxyl radical on introduced organisms were pre-ever several tonnes were needed to treat largesented.amounts of ballast water in a jumbo carrier callingfor a port area without any cargo. In addition, bothinorganic and organic biocides would present a2 BIOCHEMISTRY PROCESSES OF HY-range of health and safety problems related to theDROXYL RADICAL ON ORGANISMSstorage and handling of the chemicals, their com-patibility with cargoes carried on board ships, as2.1 Lipid peroxidationwell as those related to the direct and indirect han-dling of chemicals by crew members (Muller, 1995).Also the klling duration of biocides needs above 20A cell is the basic structural and functional unitminutes, which is impossible to treat over hundredsof organisms in ballast water. The cell membrane orthousand ballast water on board. Although a lot ofbiomembrane with the thickness of4 -7 nm, is com-research works were done in the world, Marine En-posed mainly of protein including enzyme, lipidvironment Protection Committee (MEPC) and(primarily phosphatide and amylose), water, metalGloBallast think that so far no high efficient, lowions and so on, in which phosphatide is key struc-cost, non-residual method could be used for treatingtural unit and consist mainly of phosphoglyceride.the ballast water,The phosphoglyceride has a saturated fatty acidWith the physics method of micro-gap gas dis-molecule and an unsaturated one. The unsaturatedcharge (Bai, 2003; Bai, 2002), a strong electric fieldfatty acid molecule commonly links with the second(Ed2400Td, lTd=10"Vcm2) is formed with a thin-carbon atom of glycerin, which is easy to carry on aner a-Al2O3 dielectric layer at a high pressure (Pseries of reactions with hydroxyl radicals such as the20.1MPa or n=2.6x 10'9/cm). The electron energylipid-bond break, carbon chain break and hydrolyzein micro-gap conforms to an energy distribution law,of unsaturated fatty acid as following (1)(Kong,in which a lot of electrons have the energy of2000).≥12.6eV for the ionization of H2O (potential energy:Hydroxyl radicals oxidize the unsaturated bond12.6eV) and O2 (12.5eV) contributing to the pro-in -R2 chain. In the reaction (2) of Kong (2000), theduction of OH° radicals. In previous papers (Bai,carboxylic acid decomposed from phosphoglyc-2005; Zhang, 2004; Zhou, 2003), the plasma proc-erides is finally decarboxylated to CO2 and H2O be-esses for OH' formation and the killing of invasivecause of the strong oxidation of OH. Cell membranemarine species were reported. With 20th experi-separates the inside and outside environment of cell,CH2-OHCH2-0-C- R,R-C-0- CHOH-CH。+ R,C0O" + R2COO'(1)CH2-0 P-0 xCH-o-p 0-xOH '中国煤化工R2 CH-C-OHR-CH- C- Or(2).MYHCNMHGNo.2ZHANG et al: Treating bllat water with hydroxyl radical on introduced organisms163and its selective permeability is the elementary con-Protein, an important substance to keep the lifedition for cell activities. Lipid peroxidation causesfunctioning, is composed of the amino acid linkedthe cell membrane destruction and the content over- with peptide bonds. The amino acid is oxidized andflowing would finally result in the cell death.decomposed by hydroxyl radicals shown in reaction(3) of Kong (2000). Owing to different R radicals,2.2 Oxidation and decomposition of amino acidR-CH2-NH2 is continually oxidized.R CH- COOH_OH +R- CH NH2 +H20+ CO2(3)2.3 Protein structure changeHydroxyl radical makes the disulfide bond be oxi-Hydroxyl radicals cause the peptide bonds todized and broken to change the space structure ofbreak down and protein to denaturalize. Someprotein, resulting in denaturalizing the proteins oramino acids have activated radical of sulfhydryl -SHdisabling the enzymes, and finally killing the cells.to form disulfide bonds, which is an importantThe reaction of disulfide bond break is as followingchemical bond to keep the protein space structure.reaction (4) (Kong, 2000).H2N一 CH - COOHH2N-CH一COOHCH2OH iSOH(4)H2N- CH COOHH2N- CH - COOH2.4 DNA chain break3.1 Experimental materialsDNA is an important inheritance molecule inThe tested seawater was taken and put into athe bodies of invasive marine specie. Hydroxylglass trough of 1.5m*. A lttle of liquid culture me-radicals combine with DNA to form DNA Addcuts, dium of 2216E were put into the trough to enrich thewhich is a forepart damage of DNA, resulting inalgae and bacteria in it. The enrichment conditionssome changes in DNA structure such as the basesare as follows: the temperature, 23+1°C; pH, 7.2;replacement and loss, the chain break and so on.ilumination intensity, 2 600 lx and duration, 7 days.The bases of the glycosidic and phosphodiesterThe enriched seawater was poured into the containerlinkages in DNA are attacked by hydroxyl radicals2 (Fig.1), in which the contents of algae, protozoancausing chemical damages. Hydroxyl radicals actand bacteria were above 10*/ml. The phytoplanktonsmainly on the Cg of adenine (A) and guanine (G) asare Chloreua Pyrenoidesa, Chaetocers, and Perid-well as the 5th and 6th double bond of pyridineiniu中国煤化Iuploles the germnsbases. Also DNA is directly damaged to destroy thewerus, Vibrio, Acine-its structure leading to the cell death.tobaYHC N M H Ges, and Staphyloc-cus.3 EXPERIMENT METHOD164CHIN. J. OCEANOL. LIMNOL, 24(2), 2006Vol.243.2 20 t/h pilot-scale system for the treatment ofBefore applying the dielectric barrier discharge,ballast waterO2 with the purity of 99.5 % and H2O gas of 3.5%were introduced into the plasma reactor 12 in Fig.l.20 th pilot-scale system for the treatment ofThe gas flow rate is monitored using a Type-LZJ10ballast water using hydroxyl radicals is shown inFlow Meter. The high-concentration hydroxyl radi-Fig.1. The tested seawater was taken from Daliancals are injected into the gas/iquid dissolver 15 inHarbour and stored in BC type polyethylene con-Fig.1 further dissolved in gas/liquid separator 16 intainer 1 in Fig.1. The sample points are in fiveFig.1. With the mass transfer efficiency of 99.8%，points ofA, B, C, D and E respectively, having thethe dissolved OH ratio concentration reaches 23.4duration of0.0s, 1.33 s, 2.67 s, 5.33 s and 8.00 s.mg/L to be injected into liquid/iquid unit 6 in Fig.1The flow velocity of the ballast water is 1.5m/s, andfor the adequate mixture. The ratio concentration inthe flow rate is 20 t/h. The flow rate of ballast watermain pipeline is 0.68 mg/L. The residual hydroxylis measured with Model 8035 Burkert Flow meter 7gas is decomposed into the molecules of H2O, O2 inin Fig.2 (Burkert Co. in France). The treated ballastthe eliminator 17 in Fig.1.water flows into the gas/liquid separator 7 in Fig.1,The plasma processes of OH^ dissolving intoand then is discharged. The residual hydroxyl gas iswater are very complicated chain reactions (Bernie,decomposed into the molecules of H2O, O2 in the1997; Sun, 1999). 0H is the main product in theeliminator 8 in Fig.1.system, also having other activated particles such asHO2, HO", HO;, OH ,0,OH* ,02 ,07 ,0, H2O210D-9→-3Rovand so on.This pilot scale experiment for 20th was done，QPin December 2002, the temperature of sea water isO2,H2O 11 12 1380↑8.59C.17口183.3 Test methods↑Bacteria testThe samples of 10 ml, 100377ml and 150 ml are respectively taken from the sam-pling points, and then were diluted to 10* times in2Main pipe4Dischargeaseptic condition. Three samples are taken in everypoint for the test. The diluent of 0.1 ml is daubed onthe ocean 2216E culture plate for counting the colo-nies. The detached bacteria are selected from a sin-Fig.1 20 th system for the treatment of ballast watergle colony for the second purified separation. TheNote: 1. Container of bllasl water; 2. Valve; 3. Mechanical filter; 4. Liq-uid now-mer, 5. Pump; 6. Liquid/Liquid dislver; 7. and 16.bacterium genera is identified according to its bio-Gas/liquid separator; 8. and 17. eliminator of residual OH; 9. Contoller;logical character, cell configuration and test results10. Transformer; 11. Flowmeter; 12. OH+ plasma reactor; 13. Electricof biochemistry. The bacteria numbers in the samplevalve; 14. Check valve; 15. Gas/iquid dissolver; 18. Dissolved OH+is difficult to be accurately counted using conven-monitor; P. Pressure meter, ABCDE. Samples for testtional test method after being killed because of thegreat decrease of bacterium numbers. Therefore theThe dissolved hydroxyl radical treatment de-water sample of 150 ml is used to inoculate usingvice has the dimension of 0.6 m (long)x0.8 m (wide)filter membrane method and to daub on the oceanx1.5 m (high). The power supply with voltage of 222 16E plate to do the counts of colony.kV, frequency of 10 kHz and pulse period of 80 μsAlgae test .The samples were taken usingwas applied to the discharge electrodes to produce a2500 ml asentic elass before and after injecting OHcontinuous strong micro-gap discharges. Thinnerradic中国煤化工vere identified anda-Al2O3 dielectric layers are sprayed on the surfacecounYHCNMHGichweredonewithof discharge and earthing electrodes by plasmahaemacytometer under microscope.spraying technology. The discharge gap is 0.47 mm.Photosynthetic pigments testFollowingThe energy cost for the treatment is 50 Wh/m', notChina's national main monitoring standard of oceanconsidering the energy cost of pump.(GB17378.7-1998), UNICO7200 type spectropho-No.2ZHANG et al: Treating ballast water with hydroxyl radical on introduced organisms165tometer is used to test.about 300% after the injection of hydroxyl radical,Glucose testUNICO7200 type spectro-exhibiting a serious lipid peroxidation in cell mem-photometer at the wavelength of 630 nm withbrane. The increase in lipid peroxidation extendotoluamide coloration. Total protein: Biuret method.causes the cell protoplasm leak, and the cell loses itsNucleic acid: UV spectrophotometric method.activity and dies.Catalase (CAT): Ammonium molybdate colorimetry.Superoxide dismutases (SOD) activity: Pyrogallol25self-oxidation method; Peroxidase (POD) activity:Aminoantipyrine method.OH' concentrationThe ratio concentra-2(Chl-a .tion of OH is tested using electrochemistry methodand revised by fluorescence method of benzoic acid15(Ren, 2001). The concentration of other activated..-... 0口particles is converted into OH' concentration ac-cording to their oxidation potential.10ChI-c.5Ch1-6b4 EXPERIMENTAL RESULTS ANDDISCUSSIONS0024h4.1 Effect of hydroxyl radicals on theHydroxyl duration (S)photosynthesis pigmentFig.2 Hydroxyl duration Vs. content of photosynthesis pigmentsHydroxyl radical has strong oxidizing and dis-Note:◆. Content of chl-a; <. Preliminary content of chl-a;■.Content of carot; O. Preliminary content of carot;●. Content ofcoloring effects on phytoplankton (unicellular alga).chl-b; O. Preliminary content of chl-b;▲. Content of chl-c; O.The effect of hydroxyl radicals duration on the pho-Prelimninary content of chl-ctosynthesis pigments is shown in Fig.2. The originalcontents of chl-a, chl-b, chl-c and carotenoid are21.69, 5.62， 10.32 and 13.74 ug/L, respectively.Table 1 Effect of hydroxyl radical on lipid peroxidationWhen the dissolved OH ratio concentration was 0.6mg/L in the main pipe of ballast water, the samples0H" ratio concentration (mg/L)ltemwere taken at the five point ofA, B, C,D and E re-0.63spectively and the experiments on photosynthesisCell amount of organism6.0x 10"%/m'No algac testedpigment were done. The curves of chl-a, chl-b, chl-cand carotenoid are very similar, and the pigmentMDA 532nm .Absorbance0.0520.153contents decrease to 11.81, 2.16, 6.71 and 4.89 μg/Lafter 8 seconds respectively. The all pigment con-tents reached the lowest limit of test after 24 hours.4.3 Saccharide, protein and nucleic acid4.2 Lipid peroxidationAs shown in Table 2, the total protein contentis decreased from 1 .490x107 mg/ml to 9.93x 10Shown in Table 1, the cell amount of organismmg/ml, about 33.4% decrease efficiency, when thedecreases from 6.0x 10'%/m3 to no living cells testedhydroxyl concentration is 0.63 mg/L. The resultsand the content of MDA (malondialdehyde) in-indicate that the hydroxyl radicals have destructivecreases about twice to 294.2% when OH ratio con-function on organism protein which is too large tope filcentration is 0.63 mg/L. The results show that hy-中国煤化工，of0.22 um aper-ture.二3 to 1.29 ug/mg,droxyl radicals have an obvious action on the lipidhavinTMHC NMH Gcy. DNA is de-peroxidation of organisms.MDA is produced by the lipid peroxidation andcreased from 0.96 to 0.19 ug/mg, 80.2% decreaseefficiency.its content indicates the extent of peroxidation. Inthis experiment, the content of MDA increased to166CHIN. J. OCEANOL. LIMNOL, 24(2), 2006Vol.24Table 2 Efeet of hydroxy1 radical on the saccharide, protein and nucleic acidSampleOH" concentration (mg/L)GlucoseTotal proteinNucleic acid (ug/mg)(m/m)(mg/ml)RNA .DNAOrganism2.46x101.490x1022.430.960.634.92x1039.93x1031.290.190FiltrateNote: - no testDNA is mainly in the chromosome of karyon,cells death. As a result, the contents of saccharide,the rest DNA in chondriosome and few DNA disso-protein and nucleic acid decrease sequentially withciated in the cytoplasm. RNA exists mainly in cyto-the time.plasm, a small amount of RNA in nucleolus. Theabove experimental data prove that the hydroxyl4.4 Antioxidant enzymeradicals cause the destruction of karyotheca andchondriosome resulting in the damage of RNA andDNA in them. RNA and DNA have diferent struc-The effect of hydroxyI radical on antioxidanttures. DNA consists of two chains linking withenzyme is shown in Table 3. Peroxidase (POD),bases. Hydroxyl radical has strong oxidation actioncatalase (CAT) and superoxide dismutase (SOD)on C8 double bonds of adenine, and guanine as wellconsist mainly of the antioxidant enzyme system ofas s, 6 double bonds of pyridine bases. Therefore,organism. When OH”ratio concentration is 0.63DNA with the double helix structure is more easilymg/L, POD is decreased from 3.2x10s to 2.5x 10-5to break and lose activity. Hydroxy| radical degradesU/mg, 21.9% decrease fficiency. SOD is reducedthe big molecules amylose in organism body to thefrom 6.350 to 2.1910 U/ml, 54.2% decrease fi-monose resulting in the increase of content of glu-ciency. CAT is not tested before and after the reac-ose. Therefore, the big molecule is easier to be de-tion. In the seawater that organism cells are filteredstroyed than the small molecule.out, the activities of CAT and SOD are tested. TheThe efect of hydroxyl radical on the three ba-enzyme activities of CAT and SOD are decreased tosic life substances is less than that of kill eficiencysome extents because of strong oxidation of hy-of organism. Some protoplasm in the cell does notdroxyl radical. CAT is decreased from 3.770 tocompletely loss the activity temporarily when hy-0.637 U/ml, 83.1% decrease efficiency. SOD is de-droxyI radicals kill the algae cells. However, the lifecreased from 1.230 to 0.822 U/ml, 33.2% decreasesubstances will quickly loss the activity with theefficiency.Table 3 Efeet of hydroxy1 radical on the antioxidant enzymeOH Ratio concentaion (mg/L)PODCATSOP(/mg) .(U/ml)(U/m) .3.2x105-6.3502.5x1082.910Filrate3.7701.230.637中国煤化工The enzyme activities of CAT and SOD are in ifCells From experi-low level at normal cell's state. However, the cellmentMYHC NMH Gnd of poein de-can secrete large amount of activated enzymes whencrease as the total protein decrease due to the reac-the cells are atacked. The content of CAT and SODtion of hydroxyI radicals. The decrease of enzymewould be increased and their activities be enhancedactivities in some extents indicates that hydroxy1167No.2ZHANG et al: Treating bllst water with hydroxyl radical on introduced organismsradicals not only inhibit and decompose the en-Analysis of Non-Thermal Plasmas Used for Pllutionzymes at normal cell state but also do iritatet andControl. Jap. J. App Plhys 36(7B): 5007-5 017.increase the enzymes actvities by its oxidativeCarton, J. T, 1994. Biological invasions and biodiversity instress. Therefore, the amounts of decreased enzymesthe sea: The ecological and human impacts ofare actually much more than those in above experi-non-indigenous marine and estuarine organisms. Proc.mental data. The three kinds of enzymes are theConf. Wkshop. NOAA, p.5-11.important functional enzymes in cll's anti-oxidantAnderson, M., 1997. Tuming back the harmful red tide. Na-enzyme system. The experimental results provedture 388: 513-514.that the anti-oxidant enzyme system was almost de-Geof, R. 20000 From bllat to blillbasse. Science 289:stroyed by hydroxyl radicals.241.Ruiz, M.2000 Global spread of micorganisms by ships.Nature 408: 49-50.Hallegraf, G. M.. C. J. Bolch, 1992, Transport of diatom5 CONCLUSIONSand dinflagllate resting spores in ships' bllst water:Implications for plankton biogeography and aquaculture,Treating ballast water with hydroxyI radical,J Plankton Res. 14(8); I 067-1 084.the contents of chl-a, chl-b, chl-c and carotenoid areHolmes J. M. C, D. Minchin, 1995. Two exotic copepodsdecreased by 35% 64% within 8.0s and further toimported into Ireland with the pacific oyster Crasso-the lowest limit of test in 5 minutes. The .content ofstrea gigas (Thunberg)",Ir Nat. J.25: 17-20.phaeophytin is increased ten times. Hydroxy| radi-Kong, F. x, 20000 Environmental Biology. Beijing Educa-cals make phytoplankton lose its activity fnally re-tion Press, Beijing, p. 68-94.sulting in all unicellular algae to be killed.Mackenzie, M, 999 Alien invaders. New Scientist 162:Biochemistry processes is the main reasons of18-19.organism cell death. In OH' ratio concentration atMiller, K.. 1995. Disinfection of bllat water. A review of0.63mg/L, the lipid peroxide degree is increasedpolential options. Lloyd's Register, p.29+ appendix.three times. The basic life substances, monose,Ren, x. R. and x. Y. Tang, 2001. The determination of hy-amylose, protein, DNA and RNA of cell, are greatlydroxy1 radical concentration in atmosphere. China En-destroyed. Also CAT, POD and SOD of antioxidantvironmental Science 21(2): 115-118. (in Chinese)enzyme system are obviously destroyed.Rigby, G. and G. M. Hllgaef, 1993. Ballast water ex-change trials and marine plankton distribution on theReferencesMV“"Iron Whalla". Govenment Publishing Service,Canberra, Australian. Vol.2, 123p.Armstrong, G, 1997. Bllast System Design for a Flow-Sun, C. P, J. z. Zhang and S. J. Duan, 199. Free Radicalthrough Exchange of Bllasl Water. Prepared for a tech-Biology Introduction. China Science and Technologynical meeting at the Institute of Marine Engineers,University Press, Hefei, China.London, p.11.Yount, J. D, 1990. Ecology and Management of the ZebraBai, M. D, z. T. Zhang, x. Y. Bai, M. D. Bai and N. Wang,Mussel and Other Introduced Aquatic Nuisance Species.2003. Plasma synthesis of ammonia with a microgap di-EPA Workshop on Zebra Mussels and Other Introducedelectie barier discharge at ambient pressure. IEEEAquatic Nuisance Species. Saginaw Valley State UniTrans. Plasma Sci31 (6):; I 285-1 291.versity, USA, p.1-45.Bai, x. Y, z. T. Zhang, H. Han and M. D. Bai, 2002. Re-Zhang,Z. T.. M. D. Bai, x. Y. Bai, B. Yang and xX. J. Zhou,search station and progres of n-cquilibrium plasma2004. Studies of the efet of hydroxyl radicals on pho-chemisty, Chinese Science Buletin 47(); 529-530. (intosynthesis pigments of phytoplankton in ship's ballastChinese)water. J Advanced Orxidation Technologies 7(2):Bai, x. Y, M. D. Bai, B. Yang and X. J. Zhou, 2002. Studies178-183.on the disaster and treatment of alien invaders. 1. NatureZhou.,X.J..Z. I. Zhane. x. Y. Bai. M. D. Bai, B. Yang and24(4); 223-226. (in Chinese)中国煤化工_ip's ballast water inBai, x. Y.,Z. T. Zhang, M. D. Bai and B. Yang, 2005. Kill-0HC N M H Gal. EEE Itemainaling of invasive species of ship's bllat water in 20UhConterence on Plasma Sclence. scoul. Korea. 272p.system using hydroxyl radicals. Plasma Chemistry andhtp:/laasa.io.org. The problem, Global Ballast WaterPlasma Processing 25(1): 15-22.Management Program.Penetrante, M., Bardsley 1. and Hsiao C. 1997. Kinetic