The potential of water hyacinth (Eichhornia crassipes (Mart) Solms) as a bioacummulatorl bioindicator

of arsenic in dilute solution was investigated. Results show that in the absence of a high level of phosphate,

it can remove arsenic effectively. However, in high phosphate concentration, arsenic uptake was inhibited.

A arsenic could also be leached out from the plant. Hence caution must be exercised in interpreting the arsenic

status of the aquatic environment as seen through water hyarcinth

Lee, C. K.

Low, K. S.

Universiti Putra Malaysia Institutional Repository

Removal of Arsenic from Solution by Water Hyacinth

(Eichhornia crassipes (Mart) Solms).

Pertanika 13(1), 129-132 (1990)COMMUNICATION IIIRemoval of Arsenic from Solution by Water Hyacinth(Eichhornia crassipes (Mart) Solms).ABSTRAKPotensi pokok kiambang (Eichhornia crassipes (Mart) Solms) sebagai suatu biopenuT,:iuklbiopengumpularsenik dalam larutan cair telah dikaji. Keputusan menunjukkan tumbuhan ini dapat mengalih arseniksecara berkesan jika larutan tidak mengandungi Josfat yang mempunyai kepekatan yang tinggi. Walaubagaimanapun, dengan adanya kepekatan Josfat yang tinggi pengambilan arsenik direcatkan. Arsenik bolehjuga dikeluarkan daripada tumbuhan di bawah keadaan ini. Jadi, kita mestilah berhati-hati apabilamenganggar status arsenik dalam alam sekitar akuatik melalui tumbuhan ini.ABSTRACTThe potential oj water hyacinth (Eichhornia crassipes (Mart) Solms) as a bioacummulatorlbioindicatoroj arsenic in dilute solution was investigated. Results show that in the absence oj a high level oj phosphate,it can remove arsenic effectively. However, in high phosphate concentration, arsenic uptake was inhibited.A rsenic could also be leached out Jrom the plant. Hence caution must be exercised in interpreting the arsenicstatus oj the aquatic environment as seen through water hyar:inth.INTRODUCTIONArsenic is a toxic element whose hazardous effectson human life is well documented (Buchanan1962; Ishinishi el al. 1986). It is a serious pollu-tant in the environment as it does not degrade likesome organic materials. Lee el aL. (1989) studied thearsenic contents of water and aquatic plants inmining pools in Selangor. Arsenic contentsofO.Ol-0. 15 /lg ml- I and 10-600 /lg g-l for thewater and plant samples respectively were report-ed. EPA guidelines for arsenic in drinking wateris less than 0.05 ug ml- I As some of these min-ing pools have the potential for fish cultivation,it is of interest to investigate the suitability of someof these aquatic plants to bioaccumulate arsenic.Water hyacinth is one of the most studiedaquatic plants as a bioaccumulator of pollutantsespecially for heavy metals (Prakash el at. 1987;Wolverston 1975). However, very little has beenreported on its capacity to remove anions. The up-take of phosphorus as 32pO was reported by4Cooley el at. (1979). This paper reports the resultsof a preliminary study of the suitability of waterhyacinth in the removal of arsenic as Na HAsO2 4in solutions. As arsenate and phospate arechemical analogues, the effect of phosphate onarsenic uptake was also investigated.METHODS AND MATERIALSAquatic plants were collected from a mining poolalong the Kuala Lumpur - Seremban Highway.Treatment of plants is as described by Low el. at(1984). In the comparative study of As uptake bywater hyacinth and hydrilla, Hydrilla verlicillala,plants of approximately 100 g were placed in beakerscontaining 1500 ml ofO.5/lg ml- 1 As (V) solu-tion. Controls without As were used to monitorphytotoxicity in plants. Samples of solution werewithdrawn at regular intervals and HCI was add-ed to render a final concentration of 1.2M.Analysis of As was by the hydride generationmethod using a Labtest-ICP-AES spectrometer.Water loss due to evaporation and transpirationwas compensated by adding water to the samelevel prior to sampling.The effect of initial concentration of As onits uptake by water hyacinth was studied by vary-ing the concentration of As solution from 0.15 to0.68 /lg ml- IK.S. LOW AND C.K. LEEThe competitive uptake of As and P wasinvestigated in 0.8 f.Lg ml- I As solution in variousphosphate concentrations.The leaching of As in water hyacinth wasconducted by using phosphate solutions of variousconcentrations.results reported by Anderson and co-workers(1980) on their study of uptake of arsenic inaquatic plants. Arsenic levels were found to be15-1200 Ilg g-l for contaminated plants.TABLE 1.As contents in various parts of a water hyacinth plantFig. J: Comparative uptake oj As by water h)'acinth and h)'drilla.RESULTS AND DISCUSSIONThe uptake of As in solution by water hyacinthand hydrilla is shown in Fig. 1. The rates of Asremoval are rapid for both the aquatic plants.Water hyacinth was capable of removing 90010 ofAs after 24 h whereas hydrilla 70% after 48 h.Thereafter equlibria seemed to have been esta-blished and no appreciable uptake was noted.1009U 08~Iu· 0'70,6Parts Dry weight Total As As (ug g- 1(ug) (l.lg) dry wcight)Roots 0.95 590 622Floatcrs O. i5 30 40LCa\TS 0.35 12 34Both plants show good potential in remov·ing As. Sub equent experiments, however, wereconducted with water hyacinth only.The uptake of ar enic by water hyacinth atvarious As concentrations is shown in Figure 2. Therate of uptake increases with increasing concen-tration. A similar observation is also reported byPrakash et al. in their study of cadmium uptakeby the same plant (1987).As (ppm)• 0·680- 0·42.-0·290-0·150234567DaysFI.~. 2: L'ptake oJ 11; b)' u'aler l~ra(lIlth III ;o{utlOn; oJ (".!.famt ,.),(oncentrations (C - initwl concentration and C-conwltrationat time I). 0The pHs of solutions with varied levels ofphosphate in a fixed amount of As arc shown inTable 2.vvo water hyacinth... hydri lIa\\.\~.\.\~'--a.-._ ..........o 23456Days20 10...)(c 80..."0 6Vlc4Vl<{~Analysis of As content in water hyacinth showsthat As was mainly located in the root system.Translocation of As appears to be a slow processin the plant. It could be due to the greater Asaffinity in the root system. In general all arseniccompounds are strongly adsorbed to root surfacesfrom solution. This adsorption is apparentlylimited only by availability. More toxic arseniccompound is less readily translocated from the rootsystem. (Sachs and Michaels 1960). A typical Asanaysis of a single water hyacinth plant is shownin Table 1. These values are comparable to the130 PERTANIKA VOL. 13 10. I, 1990REMOVAL OF ARSE IC FROM SOLUTION BY WATER HYACINTHTABLE 2The pHs of solutions before and after uptake bywater hyacinth (As: 0.8 ppm)Initial pH depends on the phosphate concentra-tion. At the end of the uptake (6 days) all solu-tions show an increase in pH. This is probablydue to the reduction of phosphate concentrationin the solution. Subsequent measurements con-firmed the above statement.Analysis of aquatic plants generally providesome information on the status of contaminationof the aqueous system by a particular pollutant.This is true only if the presence of other substancesdo not affect its uptake. Figure 3 shows the effectof phosphate on the uptake of As by water hya-cinth. At low phosphate level (llJ.g ml- 1), the Asuptake was not affected. Presumably there wereenough binding sites in the plant for both As andbefore afterpH3-P04 ppm·-10-10\7- 100• - 500phosphate. At a higher phosphate level ( '> 100 IJ.gml- 1), the uptake was not only suppressed butthe original As in the plant tissues was displacedby the phosphate. This reflects that the plant hasa greater affinity for phosphate than arsenatedespite the fact that both are chemical homologues.Hence, caution must be taken in interpretingresults of such a system. The absence or low levelof As in plant does not necessarily reflect the samestatus in the aqueous environment.Figure 4 shows the leaching of As from waterhyacinth in various phosphate solutions. In theabsence of low phosphate concentration, nodisplacement of As was noted. The displacementbecame more pronounced with increasing concen-tration. This result is in agreement with the earlierobservation that in water hyacinth, phosphatebinds morc strongly in the plant tissues thanarsenate.6.76.56.15.75.85.55.24.910100500Phosphate concentration(ppm)0·4•o 2 4 6 8 10 12 14Days0'30'1E0.0.u 0'2CONCLUSIONPreliminary results show that water hyacinth couldbe used as a bioaccumulator for As provided thesolution contains no or low levels of phosphate.Fi~. 4: Fjfect oj phosphate concentratIOn on the dlSplacemmt oj Asin u'aler h)'acinlh.o 234 5 6Dayst.jjecl oj pllOsphote on the uptake oj As b)' u'aler hJacinlh.-0103-0 P04 (ppm)x 8 e- O"'"10... • 10;j 60 0 100<Jl.. 500c4<Jl \<l: '\~ 2Ft~. JPERTAi\IKA \'01.. 13 NO. I, 1990 131K.S. LOW AND C. K. LEELOW, K.S.LEE, C.K.REFERENCESANDERSO , A.C., A.A. ABDELGHA I and D. McDo ELL. 1980. Screening of Four Vascular AquaticPlants for Uptake of Monosodium Mechanearsonate(MSMA). Sci. Total Environ. 16: 95-98.BUCHANAN, W.D. 1962. Toxicity of Arsenic Com-pounds. New York: Elsevier Publishing Com pany.COOLNY, T.W., M.H. GONZALEZ and D.F. MARTIN.1979. Radio Manganese - Iron, and PhosphorusUptake by Water Hyacinth and Economic Implica-tions. Economic Botany 34(2): 371-378.ISHI ISHI . TSUCHIYA, K, M. VAHTER and B.FOWLER. 1986. Handbook on the Toxicology ofMetals, ed. L. Friberg, G.F. ordberg and V.Vounk, 2nd edn. p. 43-83. Elsevier Science Publish-ing B.V.LEE, C.K. 1989. Personal communication.Low, K.S., C.K. LEE and S.H. TAN. 1984. SelectedAquatic Vascular Plants as Biological Indicators forHeavy Metal Pollution. Pertanika 7(1): 33-47.PRAKASH, 0, 1. MEHROTA and P. KUMAR. 1987.Removal of Cadmium from Water by WaterHyacinth. Enviro. Engng. 113(2): 352-365.WOLVERSTO , B.C. 1975. Water Hyacinth forRemoval of Cadmium and ickel from PollutedWaters. ASA Technical Memorandum TM-X-72721.ISHI ISHI ,K. TSUCHIYA, M. VAHTER and B.FOWLER. 1986. Handbook on the Toxicology ofMetals, ed. L. Friberg, G.F. Nordberg and V.Vouk, 2nd edn. p. 43-83. Elsevier Science PublishingB.V.SACHS, R.M. and J.C. MICHAELS. ComparativePhytoxicity Amount Four Arsenical HerbicidesWeed Sci. 19: 558-564. 'WOLVERSTON, B.C. 1975. Water Hyacinth forRemoval of Cadmium and ickel from PollutedWaters. ASA Technical Memorandum TM-X-72721.Department of Chemistry,Universiti Pertanian Malaysia,13400 UPM, Serdang, Selangor DaTUl Ehsan,Malaysia.(Received 25 August, 1989)132 PERTA 1KA VOL. 13 NO. I, 1990

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Removal of Arsenic from Solution by Water Hyacinth (Eichhornia crassipes (Mart) Solms).

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