A Biomonitoring of Plankton to Assess Quality of Water in the Lakes of Nagpur City

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1 Sengupta, M. and Dalwani, R. (Editors) Proceedings of Taal2007: The 12 th World Lake Conference: A Biomonitoring of Plankton to Assess Quality of Water in the Lakes of Nagpur City Pramila Kumari 1, Sharda Dhadse 2*, P. R. Chaudhari 2 and S. R. Wate 2 National Institute for Occupational Health, Ahmadabad National Environmental Engineering Research Institute, Nagpur *Corresponding author: Sharda.dhadse@gmail.com ABSTRACT The present study deals with the role of biological parameter especially plankton community and its trophic status to assess water quality of four selected lakes in the Nagpur city. Pollution status of lakes were assessed on the basis of the Palmer s Pollution Index, Shannon Wiener Index and physico-chemical parameters. A total of 57 genera belonging to 7 groups of phytoplankton and 10 genera belonging to 3 groups of zooplankton were identified from the lakes. Different patterns of dominance and subdominance of indicator plankton community and species along with physico-chemical quality observed confirms the pollution status of the lakes. Keywords: Lake Water Quality, Plankton, Palmer s Pollution Index, Shannon Wiener Diversity Index INTRODUCTION Biological monitoring is valuable method used in conservation studies to protect and preserve the biological integrity of natural ecosystem, which includes preventive measures. Bioindicators of pollutants are useful in predicting the level and degree of the pollutants before the effects of the pollutants starts, which caused large proportions (Pai 2002, Verma 2002, Ward and Whipple 1966). Study of these organisms is generally linked to the use of mathematical distribution (Legendre 1983) of these organisms in the communities to which the bioindicator species belong (Singh and Singh 2003, Joy and Joseph 1995). Qualitative and quantitative analysis of different groups of organisms have led to establishment of bio-indicators, indices and systems which can be used to asses the pollution and trophic status of water bodies. Different indices (Palmer 1969) have been developed based on the tolerance of algae to the pollution levels (Battish 2002, Bhati 1987, Sladecek 1983). Presently biomonitoring (Mahadev et al. 2005) and indices (Kannel et al. 2007) have become an integral part of water quality assessment and forms part of many water pollution studies. This study deals with assessment of water quality status of 4 selected lakes of Nagpur city using Shannon Wiener Diversity Index (SWDI) and Palmer s Pollution Index (PPI) values based on qualitative and quantitative analysis of phytoplankton and zooplankton community and physicochemical quality of water. SWDI gives accurate value of population diversity and is applied to a large extent by limnologists. MATERIALS AND METHODS Nagpur city, an urban area is dotted by four prominent lakes viz. Ambazari, Phutala, Gandhisagar and Gorewada. Environmental surveillance of lake surroundings was carried out to identify the atmospheric activity and sources of pollution to the lake. The water samples for biological and physicochemical analysis were collected in June and August 2004 to cover the critical pre-monsoon season and the impact of monsoon season on lake water quality. Physicochemical and biological analysis was carried out according to standard methods (Clercesi et al 1993). Shannon Wiener Diversity Index used to assess water quality is based on total number of species and their relative concentration in the water sample. RESULTS AND DISCUSSION The water quality of selected four lakes was evaluated with respect to their suitability for designated use and to establish their trophic status and pollution levels. Out of these four lakes, Gorewada Lake is used as a source for drinking water, Ambazari Lake is for recreational purpose in addition to irrigating urban plantation in Nagpur City, Phutala and Gandhi Sagar Lake is for fishery purpose as well as for immersing idols during festivals besides being used for recreational and religious purposes. Physico-chemical Quality The ph of the lake water was found to vary from 8.07 to 8.46, being highest in Gandhi Sagar Lake. Alkalinity ranged from mg/l to mg/l.

2 The value was above drinking water quality standards (CPCB manual) in Gandhi Sagar lake. The turbidity varied from 0.6 to 5 NTU (Table 1). Conductivity (µs/cm) and total dissolved solids (mg/l) were found to vary from 346 to 1150 and from 222 to 742 respectively. Both conductivity and total dissolved solids were found to be highest in Gandhi Sagar Lake. Total hardness ranged from 79.2 to mg/l of the total hardness while magnesium hardness was found to be higher than calcium hardness in all except Ambazari Lake. Magnesium hardness varied from 43.16% to % of total hardness. Though Chlorides were least in Gorewada lake (4.45 mg/l), it ranged from to in other lakes being highest in Gandhi Sagar lake whereas sulphate was observed to vary from to 45.0 mg/l. Nitrate was observed to vary from 0.25 to 1.45 mg/l, being highest in Gandhi Sagar indicating nutrient addition and magnification of pollution. The Phosphate was highest in Phutala due to anthropogenic activities varying from 0.30 to 1.26 mg/l. The above discussion shows that among the four lake in Nagpur, water quality of Gorewada lake is best. This justifies its use as drinking water source. It is also protected from human activity and sources of water pollution. Among other lakes, Gandhi Sagar lake appears to be highly polluted having high values of physical and chemical parameters (alkalinity, conductivity, total dissolved solids, total suspended solids, total hardness, chloride and nitrate). This was due to uncontrolled use for solid waste disposal by surrounding people. The lake also showed dense growth of macrophytes (including water hyacinth) in shallow portion of lake. Ambazari and Phutala lakes showed enrichment of water that may be due to man made sources of pollution. These lakes show the starting of mesotrophic conditions and require immediate attention to conserve the lake water quality. Plankton Biodiversity The observations were recorded in June and August 2004 of four different lakes of Nagpur city, which showed rich biodiversity of planktons (Table 2, 3). During the study a total of 50 phytoplankton species were recorded from the lake water samples. Out of these, 10 species belonged to Cyanophyceae, 20 to Chlorophyceae, 13 to Bacillariophyceae, 4 to Euglenophyceae and 1 to Cryptophyceae, Xanthophyceae and Pyrrhophyceae each. The number of species observed in Ambazari, Phutala, Gorewada, and Gandhi Sagar lakes were 24, 25, 22, and 22 respectively. Highest diversity was obtained in Phutala lake followed by Ambazari. Though the same number of species was observed from Gorewada and Gandhi Sagar lakes the difference was in their composition. All the lakes showed either the dominance of Chlorophyceae or Bacillariophyceae. However Cyanophyceae were found to be dominant in Gandhi Sagar Lake. Low diversity of Euglenophyceae was also observed in Gandhi Sagar and Phutala lake, while it was not recorded from other lakes. Percentage composition of blue green algae was found to be increase in August in all the lakes while green algal species were increased considerably in Phutala lake following the increase of diatoms in Gorewada lake (Table 2). Table 1: Physico chemical quality of water in different lakes of Nagpur Sr. No. Parameters Ambazari Phutala Gorewada Gandhi Sagar 1 ph Alkalinity as CaCO 3 (mg/l) Turbidity (NTU) Conductivity (μsiemens/cm) Total dissolved solids (mg/l) Total suspended solids (mg/l) Total hardness as CaCO 3 (mg/l) Calcium hardness as CaCO 3 (mg/l) Magnesium hardness as CaCO 3 (mg/l) Chloride(mg/L) Sulphate (mg/l) Nitrate (mg/l) Phosphate (mg/l)

3 Table 2: Phytoplankton community structure and biological indices of water quality (June and August 2004) Name of Lake Total Phytoplankton no/ml Bacillariophyceae Cyanophyceae Percent Composition of Groups Euglenophyceaphyceae Crypto- Xanthophyceae Pyrrhophyceae Chlorophyceae Shannon Wiener Diversity Index Ambazari June August Phutala June August Gorewada June August Gandhi Sagar June August Palmers Pollution Index Ambazari Lake The total phytoplankton was found to vary from 2042 to 1625 algae/ml in June and August respectively. Reduction in total count is accompanied by increase in SWDI value from to during this period there is increase in the biodiversity, which is due to mineralization of lake water in rainy season. These two parameters are the important indicators of diversity. SWDI in Ambazari lake indicates availability of enough nutrients for biological growth. In June presence of organic pollution in lake water is supported by biological observation that phytoplankton community is dominated by Chlorophyceae (55.7%) and subdominated by Bacillariophyceae (27.9%) and Cyanophyceae (15%) (Table 2). The high percentage composition of Chlorophyceae and Cyanophyceae indicates higher productivity of Ambazari lake water was due to nutrient enrichment. In August, dilution of lake water due to runoff water resulted in shifting the dominance from Chlorophyceae to Cyanophyceae and reduction in the composition of Bacillariophyceae. The dominant species observed were Chlorococcum sp., Oscillatoria sp., Selenastrum sp., Fragellaria sp., and Lyngbya sp., while all other algae were common or rare. The diatoms percentage (47.6%) as pollution indicators show the trophic level to be β- mesotrophic. The zooplankton density (number/l) varied from 155 to 549. This density is equivalent to number of zooplankton in good quality productive lake. The SWDI varied from 2.62 in June to 2.25 in August. Zooplankton community was dominated by Rotifera both in June (60.2) and August (72.4%). Cladocera was subdominant in June and Copepoda in August. The presence of pollution indicator species such as Brachionus and Keratella along with clean water indicator species like Daphnia, Cyclops and Nauplius indicates a good water quality of lake with presence of some organic pollution (Table 3). Phutala Lake Total phytoplankton count in Phutala Lake varied from 6572 to 1274 No/ml in June and August respectively (Table 2). Algal count is high in June showing mesotrophic level of pollution. In August, though the number was less, the dominance of Chlorophyceae (71.8%) and Cyanophyceae (18.3%) indicates the presence of organic pollution. Phutala Lake with a total number of 25 algal species is highest among all the lakes under study. This indicates nutrient enrichment of lake above the level of limiting concentration resulting in higher diversity of phytoplankton. This is supported by SWDI ranging from in June to in August. Biodiversity index is slightly lower than that in Ambazari lake as Phutala lake shows very high dominance of pollution indicator species like Oscillatoria and fragellaria. In Phutala lake number of pollution indicator species (11) is highest among all the lakes with percentage composition 38.2%, which is also highest among all the lakes. The prominent pollution indicator in Phutala lake are Fragellaria, Oscillatoria, Chlorococcum, Ankistrodesmus, Synedra and Selenastrum. This observation is also supported by higher values of PPI, which range from 23 to 24 indicating presence of higher level of organic pollution. 162

4 Table 3: Zooplankton community structure and biological indices of water quality (June and August 2004) Sr. Total Percent Composition of Groups Name of Lake No. zooplankton no/l Cladocera Rotifera Copepoda Shannon Wiener Diversity Index 1 Ambazari June August Phutala June August Gorewada June August Gandhi Sagar June August Total zooplankton count varied from 467 to 688 No/L in June and August 2004 respectively. Rotifera was dominant whereas Copepoda was observed to be sub-dominant. Rotifera is indicator of water pollution and the pollution indicator species recorded from the lake were Brachinus sp., and Keratella sp. The total zooplankton count is comparable to the polluted lakes and it may show α mesotrophic level of water quality. The presence of pollution indicator species and values of SWDI support this observation. SWDI was observed to vary from 2.06 to 2.99 indicating presence of organic pollution in Phutala lake (Table 3). Gandhisagar Lake Total phytoplankton count in Gandhi Sagar Lake varied from 4997 to 6694 No/ml in June and August (Table 2). This density of phytoplankton is comparable to eutrophic lakes. This observation is supported by the dominance of pollution indicator groups and species in the lakes. Cyanophyceae followed by Chlorophyceae, which are indicators of organic pollution, dominates the community structure of phytoplankton in Gandhi Sagar Lake. The diatoms, indicator of clean water quality, are less in percentage composition in June (3.1) and August (7.0%). The lake also shows presence of Euglenophyceae in June, which is the best indicator of organic pollution. Other dominant pollution indicator species recorded from the lake are Oscillatoria, Scenedesmus, Ankistrodesmus and Navicula. PPI was 22 in June and 14 in August, thus indicating the presence of high organic pollution in summer season and low in rainy season. This low value in rainy season is due to mineralization of the shallow lake and higher dilution factor because of the runoff water. Total zooplankton count varied from 402 to 181 No/ml in June and August respectively. This count is comparable to that obtained in polluted lakes. This observation is supported by the dominance of Rotifera (77.6 to 87.6%), which is indicator of organic pollution. The organic pollution indicator species recorded in lakes were Brachionus and Keratella species. Brachionus forms the highest percentage in zooplankton community. SWDI varied from 1.58 (August) to 2.93 (June) showing reduction in biodiversity due to pollution especially in August. The higher level of eutrophication in Gandhi Sagar Lake is due to the fact that lake doesn t have a source of clean water and the level of lake is replenished by wastewater coming from the city. The lake is also used as disposal sites for solid waste. Gorewada Lake The Gorewada lake showed total phytoplankton count ranging from 193 to 572 No/ml, which is generally obtained in clean water lakes. The phytoplankton community showed dominance of diatoms (65.5%), indicating good water quality. The SWDI value of 3.96 shows higher biodiversity and PPI of 9 shows very low organic contamination in lake support this observation. An increase in total algal count was observed during the August with the dominance of Cyanophyceae (59.2%) and sub-dominance of Bacillariophyceae (31.6%). This indicates the presence of nutrients and waste organic matter. In summer season, the lake stratification might have been responsible for low algal count in lake water due to depletion of nutrients in surface layer of lake. In August, the mixing of vertical layers of lake and runoff water from catchment area might have added nutrients and organic contamination to whole lake resulting in increase of total phytoplankton count and presence of organic pollution indicator group. Cyanophyceae and organic pollution indicator species like Oscillatoria, Merismopedia, Microcystis indicating marginal presence of organic contamination in lake water. Total zooplankton count varied from 29 (in June) to 12 No/L (August). Copepoda dominated zooplankton community both in June (63.2) and 163

5 August (68.8%). Rotifera was observed to be subdominant in June whereas Cladocera was subdominent in August. The shift in dominance from Rotifera to Copepoda indicated clean water quality of Gorewada Lake. The SWDI varied from 3.27 (June) to 1.91 (August) supports the observation that the water quality is good at Gorewada lake and can be used for drinking water supply. Impact of Monsoon Season The lakes showed interesting observations in premonsoon and monsoon period. In Ambazari and Phutala lake phytoplankton count was reduced while it shows increase in Gorewada and considerable decrease in Chlorophyceae and Bascillariophyceae. This indicates mixing of lake water and mobilization of nutrients in lake water. In Gandhisagar lake water is always in mixed condition and no prominent changes were observed. In Phutala lake there is increase in Chlorophyaceae whereas in Ambazari lake there is increase in Cynophyceae. This shows that mixing of lake water and nutrient mobilization is more in Ambazari Lake. CONCLUSION The observations on lakes in pre-monsoon season were environmentally significant as they indicate the level of water column due to mixing of lake water. Gorewada lake showed least impact on nutrient mobilization indicating less accumulation of nutrient in bottom layer. Thus restoration of a Gorewada lake is less costly and may be carried out by oxygenation of bottom layers or regular addition of fresh water to lake. The results showed that nutrients and pollutants are locked in largest quantity in Gandhisagar lake followed by Ambazari and Phutala lake. Therefore scavenging of polluted sediments and regular addition of fresh water to lake are the proposed methods for lake restoration in case of Gandhisagar lake. Ambazari and Phutala lake are polluted by autocthonic sources of pollution i.e. growth, death and degradation of macrophytes in lake. Regular clearing of macrophytes to remove pollutants from lake is the best way for the restoration of Ambazari and Phutala lake. The physico-chemical and biological observations on different lakes in Nagpur City indicate the present status of lake with respect to pollution levels and trophic status. Physico chemical evaluation indicates Gorewada lake to be of best quality among all lakes and is thus suitable for its use for public water supply. However, biological evaluation shows that water quality has reached threshold level and unless and until correctives steps are not undertaken it will be difficult to maintain water quality. REFERENCES Battish, S. K. (2002). Zooplankton of polluted waters, cited in Ecology of Polluted Waters. Volume 1. Ed., Kumar, A. A.P.H. Publishing Corporation, New Delhi. Bhati, D. P. S. and Rana, K. S. (1987). Zooplankton in relation to abiotic components in the Fort Coat of Bharatpur. Proc. Nat. Acad. Sci. India 57 (B): Clercesi, L. S., Greenberg, A. E. and Eaton, A. D. (1998). Standard Methods for the Examination of Water and Wastewater. 20 th Edition. American Public Health Association, American water works Association and Water Pollution Control Federation Hortobagyi, T. (1973). The Microflora in the Settling and Subsoil Water Enriching Basin of the Budapest Waterworks. Akademiakido, Budapest, 341. Joy, C. M., and Joseph, A., (1995). Pollution and Biomonitoring. Edited by Rana, B. C. Tata Mc Graw Hill Publishing Company Limited. Kannel, P. R., Lee, S., Lee, Y. S., Kannel, S. R. and Khan, S. P. (2007). Application of Water Quality Indices and Dissolved Oxygen as Indicators for River Water Classification and Urban Impact Assessment. Environ. Monit. Assess. 132: 1-3 Legendre, L. and Legendre, P. (1983). Numerical Ecology, Developments in Environmental Modeling 3. Elsevier Scientific Publishing Company, New York. Mahadev, J. and Hosamani, S. P. (2005). Algae for biomonitoring of organic pollution in two lakes of Mysore city. Nat Environ Pollut. Technol. 4: Pai, I. K. (2002). Cited in Ecology of Polluted Water. Edited by., Kumar, A. A.P.H. Publishing Corporation, New Delhi. Palmer, C. M. (1969). A composite rating of algae tolerating organic pollution. J. Phytocol. 5: Singh, R. and Singh, S. P. (2002). Ecology of Polluted Waters. Volume 2. Edited by Kumar, A. A.P.H. Publishing Corporation, New Delhi. Sladecek, V. (1983). Rotifers as indicators of water quality. Hydrobiologia 100: Verma, J. P. (2002). Ecology and Ethology of Aquatic Biota. Volume 1. Edited by Kumar, A. A.P.H. Publishing Corporation, New Delhi. Ward, H. B. and Whipple, G., C. (1966). Fresh Water Biology. Second edition. Edited by Edmondson, W. T. John Wiley and Sons, Inc., New York. 164