Determination of Heavy Metal Content in Water, Sediment and Micro Algae From Lake Victoria, East...

8/3/2019 Determination of Heavy Metal Content in Water, Sediment and Micro Algae From Lake Victoria, East Africa

1/6

156 The Open Environmental EngineeringJournal, 2011, 4, 156-161

1874-8295/11 2011 Bentham Open

Open Access

Determination of Heavy Metal Content in Water, Sediment andMicroalgae from Lake Victoria, East Africa

D. O. Ogoyi1, C.J. Mwita

2,*, E.K. Nguu

1and P.M. Shiundu

3

1Department of Biochemistry, University of Nairobi, P.O. Box 30197, 00100, Nairobi, Kenya.

2 Department of Aquatic Sciences and Fisheries, University of Dar Es Salaam, P.O. Box 35064,

Dar Es Salaam, Tanzania.

3Department of Chemistry, University of Nairobi, Kenya.

Abstract: Lake Victoria, which is the largest fresh water lake in Africa, represents a unique ecosystem that has the largest

fresh water fishery in the continent. However, increased anthropogenic activities has increased the potential pollution of

the lake especially the heavy metal pollutants which may be toxic to humans and aquatic fauna. There is need therefore

for continuous monitoring of pollution levels in the lake. Samples of water, soil sediments and algae were collected in dry,

long and short rainy periods of 2008 and analyzed for heavy metal by Atomic Absorption Spectrophotometry. The highest

concentration of trace metals were found in sediment samples with Zn having the highest mean concentration values inboth Winam (1.019 ppm) and Mwanza gulf (0.889 ppm). The mean concentration of Pb was higher in water samples from

Winam gulf (0.823 ppm), while Hg in microalgae samples from Winam gulf had a mean concentration of 0.000148 ppm.

The highest concentration of Zn (1.589 ppm) was determined in the sediment samples from Kirumba bay of the Mwanza

gulf and the lowest was in sediments from Kishimba bay (0.327 ppm). Levels of trace metals in microalgae were not

significant in different sites of the Mwanza Gulf. Like in the Mwanza gulf, levels of Zn was high in sediments from all the

sites sampled in Winam Gulf, the highest recorded at Kisat. Pb levels were highest in the water samples from Hippo point,

whereas concentration levels of Cd, Cr and Hg were lowest in all the four sites sampled. The maximum biomass of micro-

algae occurred at Kisat during the short rain season (November-December) followed by Kamito in the same season.

Keywords: Heavy metals, water, sediment, microalgae, pollution.

INTRODUCTION

Aquatic ecosystem is the ultimate recipient of almosteverything including heavy metals. Pollution of heavy metalsin aquatic environment is a growing problem worldwide andcurrently it has reached an alarming rate. There are varioussources of heavy metals; some originates from anthropo-genic activities like draining of sewerage, dumping of Hospi-tal wastes and recreational activities. Conversely, metals alsooccur in small amounts naturally and may enter into aquaticsystem through leaching of rocks, airborne dust, forest firesand vegetation [1]. As heavy metals cannot be degraded,they are continuously being deposited and incorporated inwater, sediment and aquatic organisms [2], thus causingheavy metal pollution in water bodies.

The pollution sources to the Lake Victoria include anumber of industries such as shipping, mining, breweries,tanning, fish, and agro-processing factories. Industrial efflu-ents pose direct threat to the lake and its wetlands because

*Address correspondence to this author at the Department of Aquatic Sci-

ences and Fisheries, University of Dar Es Salaam, P.O. Box 35064, Dar Es

Salaam, Tanzania; Tel: 255-741537949;

E-mail: [email protected]

they are discharged directly into surface water with little orno treatment [3]. Furthermore, a study by Tole and Shitsama

[4] suggested that, concentrations of metallic pollutants aregreatest near towns, indicating their urban industrial originsWithin the lake basin, extensive mining occurs mainly inTanzania where small-scale miners use water to remove mudand impurities and mercury to collect gold [3]. The wastewater from such processes is usually disposed off into nearbystreams with ultimate destination into Lake Victoria basinOther possible sources of pollution include; domestic effluents, urban storm water runoff, landfill leachate, atmosphericsources and boating activities [5].

Earlier studies on sediment, water and biota of Lake Victoria reflected no significant heavy metal pollution [6, 7]However, subsequent studies have shown increased levels of

especially lead [8, 9]. This was attributed to increased ship-ping traffic, car washing and discharge from local industriesIn a review by Biney et al. [10], it was concluded that generally lower concentration of heavy metals occur in Africanaquatic ecosystems compared to other areas of the worldHowever, due to increases in urbanization and socio-economic activities, the threat of pollution was bound to in-crease within our aquatic systems. Similar conclusion wasmade following a study on 3000 lakes with the Nordic region


2/6

Determination of Heavy Metal Content in Water The Open Environmental EngineeringJournal, 2011, Vol. 4 15

in which the sparsely populated Northern region was foundto much less polluted compared to the south with heavy an-thropogenic activities [11]

The presence of heavy metals in the water may have aprofound effect on the microalgae which constitute the mainfood source for bivalve mollusks in all their growth stages,zooplankton (rotifers, copepods, and brine shrimps) and forlarval stages of some crustacean and fish species. Moreover,bioconcentration and magnification could lead to high toxic-

ity of these metals in organisms, even when the exposurelevel is low. Under such conditions, the toxicity of a moder-ately toxic metal could be enhanced by synergism and fishpopulation may decline. Apart from destabilizing the ecosys-tem, the accumulation of these toxic metals in aquatic foodweb is a threat to public health and thus their potential long-term impact on ecosystem integrity cannot be ignored. Thepresent study was therefore undertaken to assess the levels ofheavy metals in water and sediment from Lake Victoria andhow this relates to bioaccumulation of the pollutants in mi-croalgae. The study also aimed at determining how the levelof heavy metal pollution varies with dry, short rain and longrain seasons.

MATERIALS AND METHODS

Study Area

The study covered selected sites on Lake Victoria alongthe shores of Mwanza and Winam Gulfs (Fig. 1). These siteswere chosen due to their proximity to catchments with ac-tivities that potentially contribute to pollution of the lakeaccording to available literature [12]. The study also focusedon two less polluted areas to act as controlsone at the Wi-nam Gulf (Dunga Beach) and another at the Mwanza Gulf(Kishimba). Sampling was carried out in three major seasons

(dry, short rain and wet season) to account for seasonavariations. The samples were collected within 50-25 m fromthe landing beaches.

Sample Collection

Three seasonal samplings were carried out in Mwanzaand Winam Gulfs between March, May and September2008. Water and sediment samples were collected from althe six sites (three sites from each gulf) to analyze for heavy

metals. Water samples were collected in polyethylene bottle(washed with detergent then with double-distilled water followed by 2 M nitric acid, then double-distilled water againand finally with sampled water). Water samples were acidi-fied with 10% HNO3, brought to the laboratory and keptrefrigerated until needed for analysis. Sediment sampleswere collected using Eckman grabber and put into wide-mouthed plastic containers, kept in ice boxes containing weice during the sampling trip and later stored at -80

oC unti

analysis.

At each sampling time, algae biomass samples from thesame sites were collected using plankton nets (30 m inmesh size) and about 100 g immediately stored in dry iceand later frozen at -20

oC prior to heavy metal extraction. 250

ml of the water samples for phytoplankton analysis was col-lected and immediately fixed by a freshly prepared 0.7%Lugols solution and stored prior to phytoplankton identification and analysis.

Sample Preparation and Analysis

Each frozen sample (sediment and algae) was thawedseparately and sub-sampled for dry weight determinationat 105

oC.The otherportionofthesampleswasfreeze-dried

finely crushed and homogenized using mortar and pestleabout 0.5g of the homogenized sample was digested in 10 m

Fig. (1). Map of Lake Victoria showing the study sites


3/6

158 The Open Environmental EngineeringJournal, 2011 , Vol. 4

aqua regia -HNO3 (Loba Chemie PVT Ltd) : HCl- (Analarfrom Rankem) in the ratio of 3:1 and 1 ml perchloric acid (Loba Chemie PVT Ltd ) in a culture test tube incubated at80C in a water bath, after total digestion and subsequentcooling, the solution was diluted to 50ml and analyzed forheavy metals in a closed system by atomic absorption spec-trophotometry [13]. Heavy metals in water were analyzedusing the same equipment. 100ml of water samples weremeasured, 10ml of aqua regia and 1 ml of perchloric acidadded in a culture test tube, then incubated at 80C in a wa-ter bath, after total digestion and subsequent cooling, thesolution was diluted to 50ml and analyzed for heavy metals.The heavy metals analyzed were Zn, Pb, Cd, Hg and Cr.

Identification of phytoplankton species followed the

available keys [14, 15]. The phytoplankton numerical

abundance was evaluated by counting and Shannon diversity

index (H) was used to estimate phytoplankton species

diversity. This part was done at the Water Quality Labora-

tory in Mwanza.

RESULTS

The concentration of trace metals in water, sediments and

microalgae from Mwanza and Winam Gulfs are presented in

Fig. (2). The highest concentration of trace metals in genera

were found in sediment samples with Zn having the highes

mean concentration values in both Winam (1.01 ppm) and

Mwanza gulf (0.889 ppm). The mean concentration of Pb

was higher in water samples from Winam gulf (0.823 ppm

and the mean concentration of Hg in microalgae sample

from Winam gulf (0.000148 ppm) was the lowest trace meta

value determined in this study (Fig. 2).

Mwanza Gulf

The highest concentration of Zn (1.589 ppm) was

determined in the sediment samples from Kirumba bay of

the Mwanza gulf, followed by Nyahiti and the lowest was in

sediments from Kishimba bay (0.327 ppm). Samples o

water and microalgae from the gulf had trace amount of

metals in all the three sites sampled, with Cd and Hg having

the lowest concentration throughout the study area. Levels o

trace metals in microalgae were not significant in differen

sites of the Mwanza Gulf. Zn, Pb and Cr were detected in

samples from Kirumba and Nyahiti, whereas, levels of Hg

were high in microalgae sampled from the Kishimba site

(Fig. 3).

Fig. (2). Mean trace metal concentrations in water, sediments and microalgae from the Mwanza and Winam gulfs of Lake Victoria.

Fig. (3). Trace metal concentrations in different samples and sites of the Mwanza Gulf, Lake Victoria.


4/6


Winam Gulf

Results for heavy metals from water, sediments and mi-croalgae sampled in the four sites of Winam gulf are summa-rized in Fig. (4). Like in the Mwanza gulf, levels of Zn washigh in sediments from all the sites sampled, the highest re-corded at Kisat. Pb levels was highest in the water samplesfrom Hippo point, whereas concentration levels of Cd, Crand Hg were lowest in all the four sites sampled (Fig. 4).

Microalgae Species Richness and Abundance in Mwanzaand Winam Gulfs.

Kishimba had the highest phytoplankton species richnesscompared to the other two stations in the Mwanza Gulf. Theplankton community was dominated by chlorophytes in

terms of species richness with Scenedesmus, Surirella, Pedi-astrum and Staurastrum having most of the species. Thoughthe number of species identified differed between the sites,these variations were not statistically significant (p < 0.5224;KW = 4.190). The cyanoprokaryotes (Microcystis-flos-aquae, Anabaena-flos-aquae andMerismopedia glauca) werethe most abundant microalgae in the gulf, with Kishimbahaving the maximum biomass composed of anabaena-flos-aquae and Microcystis-flos-aquae. Microcystis-flos-aquaedominated the microalgae biomass at Nyahiti and Mirongostations (Table 1).

At Winam Gulf, the phytoplankton species richness wa

dominated by chlorophytes (Tetrastrum, TrachelomonasScenedesmus and Pediastrum genera) as was in the MwanzaGulf. Most of the Aulacoseira species was found in this guland Trachelomonas was only found in Winam Gulf. Totaphytoplankton biomass in Winam Gulf was dominated byMicrocystis aeruginosa. The maximum biomass occurred aKisat during the short rain season (November-Decemberfollowed by Kamito in the same season. Microcystis-flos-aquae occurred throughout Winam Gulf though in low abundance compared to Microcystis aeruginosa. Other species ophytoplankton were scattered an evenly in different sites othe gulf (Table 1).

DISCUSSION

Heavy metal pollution of rivers and lakes is a matter ofgreat concern in any ecosystem especially in wetlands andwater masses due to their human toxicity and bioaccumula-tive effect. In this regard, heavy metal pollution of Lake Victoria is of great interest due to its economic and domesticimplication in East African region. An earlier review on theheavy metal situation in African aquatic environment byBiney et al. [10] generally pointed to lower concentrations oheavy metal pollution compared to other areas of the worldOne of the most comprehensive studies on lake pollutionwas conducted in Europe under the Nordic lake survey in1995 that measured the heavy metal concentrations in the

Fig. (4). Trace metal concentrations in different samples and sites of the Winam Gulf, Lake Victoria.

Table 1. Microalgae Species Richness (in Bracket) and Abundance in Mwanza and Winam Gulfs

Winam Mwanza

Kisat Hippo Kamito Mirongo Kishimba Nyahiti

Cyanoprokaryotes 66765 (9) 559 (7) 19828 (7) 7738 (18) 18444 (18) 9379 (21)

Chlorophyceae 511 (13) 835 (13) 186 (11) 1113 (30) 1247 (42) 1112 (27)

Bacillariophyceae 26 (3) 139 (7) 813 (6) 316 (12) 614 (8) 357 (18)

Dinophyceae 178 (2) 8 (1) 0 2 (2) 2 (2) 6 (1)

Euglenoidea 539 (14) 140 (11) 23 (5) 0 0 0

Others 27 (5) 1 (1) 1 (1) 1 (1) 0 0


5/6

160 The Open Environmental EngineeringJournal, 2011 , Vol. 4

water of 3000 lakes [11]. The study found that among otherheavy metal pollutants, the concentrations of lead (Pb) werelow (< 0.3 g/l) particularly in the north and areas of highaltitude where the population density is low compared to thesouthern areas of the countries where there were elevatedconcentrations of up to 1-10 g/l. Our results support thehypothesis that Lake Victoria basin has significant basal con-tamination levels that however, do not reach those of clearly

polluted areas. The present study further stipulates the im- portance of applying different possible biomonitors whenstudying the quality of ecosystem. Each biomonitor, such asbenthic fauna, fish, bivalves and algae, respond differently toa particular metal fraction of an aquatic system. The lowlevels of trace metals found in this study could be broughtabout by dilution due to the influence of water waves in thelake, rainfall and rivers draining into the lake. Sedimentationcould as well account for the low levels of metals observedin different samples from the lake. Although levels of Pb andZn were below the recommended limits there was elevatinglevels of heavy metals in environment hence continuous en-vironmental pollution monitoring is required to check heavymetals hazard.

Heavy metals concentration was determined from water,sediment and microalgae samples. The results clearly indi-cate that concentration were highest in the sediment samplesfrom both gulfs compared to water and microalgae. In gen-eral, metal content in sediments is indicative of the degree ofpollution and serves as a source of solubilization into waterdepending on the physico-chemical circumstances (pH, tem-pearture etc) and the uptake by benthic organisms. At Wi-nam Gulf for instance, Zn, Hg and Cr were more concen-trated in sediment samples, the same trend was also noted inMwanza samples. Hg is the only metal known to be liquid atroom temperature and with low solubility in water. Dis-solved Hg is distributed among several chemical forms in-cluding elemental Hg, that is volatile but relatively unreac-tive, a number of mercuric species (Hg(II) and organic-Hgsuch as methyl, dimethyl and ethyl mercury. In general, thelevels of total Hg and MeHg are higher near the sediments[16]. This could possibly account for the results of our studythat indicated higher levels of Hg in sediments compared toeither water or microalgae samples. The same explanationcould apply for the other metallic elements, being non- biodegradable in nature [17], metals are commonly foundadsorbed in sediments. The presence of higher concentrationof heavy metal in sediments from this study is in agreementwith other related studies. A study on heavy metal pollutionin Lake Victoria sediments from samples collected from sev-enteen different locations around the lake town of Mwanza,

representing three zones of activities. The results showedthat sediments samples collected from southern part, whichis the industrial area, had the highest concentrations of V,Cu, Zn, As and Pb but the same were generally low in thenorthern part which is least in anthropogenic activities. An-other study on the shores of Lake Victoria, within the urbanarea of Mwanza showed elevated levels of heavy metal, no-tably Pb (54.611.1 ppm) and Zn (83.721.5 ppm) in sedi-ment samples [3]. The link between anthropogenic activ-ity and heavy metal pollution in lake Victoria was fur-ther supported bya study on the level of contamination inwetland soils and plants in lake basin around Kampala city

and Jinja districts, which are the most industrialized areas inthe Lake Victoria region in Uganda [18], the highest concentrations of 387.586.5 mg/kg Zn, 171.536.2 mg/kg Pb51.206.69 mg/kg Cu and 21.332.23 mg/kg Ni were foundaround Katanga area which receives waste from multipleindustrial sources while the lowest level was observed fromMunyonyo where there was no visible waste disposal. Similarly, Lake George in Uganda which supports a wetland with

very high biological biodiversity, suffers serious metal contamination from the nearby copper mining activity [19]Within Europe, sediments in Norwegian lakes were alsofound to have significantly elevated concentrations of HgSb, Bi, Cd, As, Ni, Cu, Pb and Zn, most likely caused byanthropogenic depositions. High levels of heavy metals inthe sediments, up to 10,000 times higher than in water, werefound in Lake Baraton. Further study on heavy metals analysis and sediment quality in urban lakes in Bangalore, Indiashowed sustained heavy metals in the bed sediments despiteelaborate mitigation measures [20]. Lake sediments aretherefore important abiotic environmental monitor for heavymetal contaminants, providing a unique medium to assesthe impact of anthropogenic pollutants on freshwater sys

tems.

Our results further indicate that there were differences intrace metal concentration in water and microalgae in the twogulfs. At Winam Gulf, for example, concentrations of metallic elements were higher in water samples than what wafound in microalgae samples. The opposite was true for wa-ter and microalgae samples from the Mwanza Gulf. The ex planation for the differences noted could be based on thability of microalgae to filter trace metals from their envi-ronment. Microalgae have thin flat surfaces and draw theirnutrients directly from the surrounding medium, when abundant at a particular site therefore, could clean-up the environment by bioaccumulation [21, 22]. Our previous repor[23] identified one hundred and sixty four species of phyto-plankton from the two gulfs, with only seventy one speciesisolated from Winam Gulf thus lower in abundance com pared to the Mwanza Gulf. Phytoplanktons are importanbioindicators of the of heavy metal pollution in aquatic ecosystems because their capacity to eliminate them from thewater and accumulate and store them over a long periodeven when the concentrations in the water is low. Severastudies have shown that submerged plants such as microal-gae tend to accumulate higher concentrations of metals consistently more than emergent or free floating plants [24, 25]Further, the efficiency of accumulation is dependent onwhether the bioindicator plant is passive or introduced aswas shown in the study in Lake Manzala [26]. The differen

tial accumulation rates of the metals in shoot and root systemof the vascular plant may however be more accurate.

The cumulative algal distributions across the two gulfsexamined in Lake Victoria were more or less homogeneousThe microalgae dominance, richness and diversity howeverwere reported elsewhere [23]. Areas like the Hippo pointthough contributed less to the total cumulative percentage oalgal classes, its contribution in terms of percentage tracemetals detected from microalgae was highest compared toother sites of the Winam Gulf. Kishimba on the other handcontributed a lot to Cd and Hg deposition in microalgae than


6/6


the other sites in the Mwanza Gulf, as a consequence, thecontribution of the Kishimba site to cumulative percentageof cyanobacteria and bacillariophytes was low. The differ-ences could be due to the fact that most metallic elementssuch as Pb, Cd, Cr and Hg are toxic and do show their dele-terious effect on aquatic biota and even to humans. The tox-icity of heavy metal increase with high water temperature,oxygen concentration, basic pH and hardness of river water.

Chances are that high levels of metallic elements at WinamGulf [23] could have contributed to the differences in micro-algae distribution across sites between the two gulfs of thelake examined.

CONCLUSIONS

The concentration of trace metals from three differentsamples i.e. water, sediments and microalgae from Winamand Mwanza gulfs of Lake Victoria were determined. Ourresults indicate that there were differences in trace metalconcentration in water and microalgae between the Winamand Mwanza gulfs. At Winam Gulf, concentrations of metal-lic elements were higher in water samples than what wefound in microalgae samples while the opposite was true for

water and microalgae samples from the Mwanza Gulf. Inboth gulfs, heavy metal concentration were highest in thesediment samples. Our results indicate that Lake Victoriabasin has significant basal contamination levels that do notreach those of clearly polluted areas. However, there is needtherefore for continuous monitoring of pollution levels in thelake.

ACKNOWLEDGEMENTS

This report is part of ongoing research that is funded byVicRes through the Inter- University Council of East Africa(ICUEA) for sustainable management of Lake Victoria re-source. The University of Nairobi (UoN) and University ofDar es Salaam (UDSM) team are grateful for this support.

REFERENCES

[1] LG Fernandez and HY Olalla, Toxicity and bioaccumulation oflead and cadmium in marine protozoan communities, Ecotoxicol-ogy and Environmental Safety, vol. 47, pp. 266-276, 2000.

[2] PM Linnik and IB Zubenko, Role of bottom sediments in thesecondary pollution of aquatic environments by heavy metal com-pounds Lakes and Reservoir: Research and Management, vol. 5,pp. 11-21, 2000.

[3] M Kishe, and J Machiwa, Distribution of heavy metals in sedi-ments of Mwanza gulf of lake Victoria Tanzania in Paper pre-sented at LVEMP conference, Kisumu, Kenya, 2001.

[4] MP Tole, and JM Shitsama, Concentrations of heavy metals inwater, fish, and sediments of the Winam gulf, in Paper presentedat LVEMP conference, Kisumu, Kenya, 2001

[5] EA Thomson, SN Looma, CE Johansson, DJ Cain, Comparison of

sediments and organisms in identifying sources of biologicallyavailable trace metal contamination, Water Research, vol. 18, pp.755765, 1984.

[6] JM Onyari, The concentra tions of Mn, Fe, Cu, Zn, Cd, Pb insediment and fish from the Winam Gulf of lake Victoria and fishbought from Mombasa town market, MSc. Thesis, University ofNairobi, Nairobi, Kenya, 1985.

[7] EN Ochieng, Limnological aspects and trace elements analysis iKenyan natural inland waters MSc thesis, University of NairobiNairobi, Kenya, 1987.

[8] JM Onyari and SO Wandiga, Distribution of Cr, Pb, Cd, Zn, Fand Mn in lake Victoria sediment, East Africa, Bulletin of Envronmental Contamination and Toxicology, vol. 42, pp. 807-8131989.

[9] SO Wandiga and JM Onyari, The concentration of heavy metalMn, Fe, Cu, Zn, Cd and Pb insediments from Winam Gulf, Ken

yan Journal of Science, vol. 8, pp. 5-18, 1987.

[10] C Biney, AT Amuzu, D Calamari, N Kaba, IL Mbome, H NaevePBO Ochumba, O Osibajo, V Radegonde and MAH Saad, Review of heavy metals in the African aquatic environment, Ecotoxicology and Environmental Safety, vol. 28, pp. 134-159, 1994.

[11] BL Skjelkvle, T Andersen, E Fjeld, J Mannio, A Wilander, KJohansson, JP Jensenhttp://www.bioone.org/doi/abs/10.1579/00447447-30.1.2 - n7#n7, and T Moiseenko, Heavy metal surveys inNordic Lakes; concentrations, geographic patterns and relation tcritical limits, AMBIO:A Journal of the Human Environmentvol. 30(1), pp. 2-10, 2001

[12] S Kayombo and SE Jorgensen, Lake Victoria: Experience anLessons learnedBrief, pp 431-445, 2005

[13] AOAC, Official methods of analysis 15th Ed, in Association oofficial analytical chemists, Washington, DC, USA, 1990.

[14] LIJ Van Meel, The Occurrence of Hydrodictyon Reticulatum (LLagerh. in Brackish Waters in Belgium,Ecology, vol. 28, No. 3pp. 317-319, 1947.

[15] O Mosille, Phytoplankton species of Lake Victoria, in Reportfrom the Haplochromis ecology survey team (HEST) operating ithe Mwanza area of Lake Victoria. Zoologisch labotorium, Morphology Department, Leiden University, Leiden, the Netherlands1984.

[16] FMN Morel, AML Kraepiel and M Amyot, The chemical cycland bioaccumulation of Mercury, Annual Review of Ecology anSystematics, vol. 29: pp. 543-566, 1998.

[17] N Malik, AK Biswas, TA Qureshi, K Borana and R Virha, Bioaccumulation of heavy metals in fish tissues of freshwater lake oBhopal Environmental Monitoring and Assessment, DO10.1007/s10661-008-0693-8., 2009

[18] G Nabulo, HO Origa, GW Nasinyama and D Cole, Assessmenof Zn, Cu, Pb and Ni contamination in wetland soils and plants ithe Lake Victoria basin International Journal of EnvironmentaScience and Technology, vol. 5, No.1, pp. 65-74, 2008.

[19] P Denny, R Bailey, E Tukahirwa and P Mafabi, Heavy meta

contamination of Lake George (Uganda) and its wetlands Hydrobiologia, vol.297, No 3, pp. 229-239, 1995.

[20] AS Jumbe and N Nandini, Heavy metals analysis and sedimenquality values in Urban Lakes, American Journal of Environmental Sciences, vol. 5 (6), pp. 678-687, 2009.

[21] EM Burrows, Assessment of pollution effects by the use of algaeProceedings of the Royal Society. London. Series B, vol. 177(1048), pp. 295-306, 1971.

[22] MG Mortuza, T Takahashi, T Ueki, T Kosaka, H Michibata and HHosoya, Comaparison of hexavalent chromium bioaccumulatioin five strains of paramecium, Paramecium bursaria, Journal oCell and Animal Biology, vol. 3(4), pp. 62-66, 2009.

[23] DO Ogoyi, CJ Mwita, EK Nguu, CO Wasoga and PM ShiunduEffect of heavy metal pollution on microalgae richness and diversity in Lake Victoria, in Lake Victoria Research Initiative Proceedings: Pollution of Heavy Metal cluster, 2009, pp. 193-210.

[24] A Crowder, Acidification, metals and macrophytes, Environ

mental Pollution, vol. 71, pp. 171203, 1991.[25] PM Outridge, and B. N. Noller, Accumulation of toxic trac

elements by freshwater vascular plants, Reviews of Environmental Communication and Toxicology, vol. 121, pp. 1 63, 1991.

[26] A Ramadan, Heavy Metals pollution and biomonitoring plants iLake Manzala, Egypt Pakistan Journal of Environmental Sciences, vol. 16(13), pp. 1108-1117, 2003.

Received: December 06, 2010 Revised: April 07, 2011 Accepted: April 10, 2011

Ogoyi etal.; LicenseeBentham Open.

This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0/g) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided thwork is properly cited.

Determination of Heavy Metal Content in Water, Sediment and Micro Algae From Lake Victoria, East...

Documents

Transcript of Determination of Heavy Metal Content in Water, Sediment and Micro Algae From Lake Victoria, East...