Water Chemistry of A National Lake of India: Lake Nainital, Uttarakhand

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1 Sengupt, M. nd Dlwni, R. (Editors).. Proceedings of Tl7: The th World Lke Conference: 9-6 Wter Chemistry of A Ntionl Lke of Indi: Lke Ninitl, Uttrkhnd P.K. Gupt, Surendr S. Ngdli, Priynk Tewri, Nirml Singh nd Rgini Gupt Deprtment of Zoology, DSB Cmpus, Kumun University, Ninitl-63, Indi pkguptku@yhoo.co.in, sngdli@yhoo.com, nirmls@yhoo.com ABSTRACT Lke Ninitl, with surfce re of h, is situted t out 937 m ove se level in the Centrl Himly, where the climte is sutropicl. The lke plys importnt role in socio-economic development of hill people. It is used for drinking wter supply, oting nd recretion. It lso mintins the locl climte s lrge mount of het is sored during summer nd the sme is relesed during winters y it. The climte thus mintined y the lke oosts tourism in the re, which is the ckone of the economy of the hill people. It is lso good repository of iodiversity. However, due to humns ctivities in lst severl yers the lke hs ecome eutrophic. For eutrophiction reversl nd to conserving it for future, the centrl s well s the stte governments re mking efforts. The present pper provides informtion on the wter qulity of the lke during 6 t vrious depths with the min ojective of presenting the se line dt efore the proposed hypolimnetic ertion to restore the lke. The dt will e useful in ssessing the impct of hypolimnetic ertion on the lke limnology. The wter ws lkline throughout the yer with nnul verge vlue of ph for the whole lke s.3. The secchi disc reding ws very low. The wter could e treted s hrd. The concentrtion of dissolved oxygen in epilimnion ws high ut hypolimnion ws noxic lmost for the whole yer. The vlues of iochemicl oxygen demnd, nitrte-nitrogen, mmonium nitrogen nd phosphtephosphorus were high. The concentrtion of free cron-di-oxide in surfce wter ws very low, some times nil. The concentrtions of micronutrients, viz. copper, zinc, iron nd mngnese, nd of fluoride were elow the permissile limit of WHO. The lke experienced regulr winter fish mortlity. Key words: Eutrophiction, hypolimnetic ertion, restortion, wter qulity, Lke Ninitl. INTRODUCTION Lke Ninitl is one of the ntionl lkes of Indi. It is situted t out 937 m ove se level in the Kumun Himly, nd is freshwter ody hving n re of h (Tle ). The lke is the min source of drinking wter supply, ttrcts lrge numer of tourists every yer, controls the locl climte nd is good repository of qutic iodiversity. The economy of the Ninitl region is directly or indirectly dependent on this lke. However, due to unthoughtful nd unplnned developmentl ctivities of the ctchment in the pst the lke hs undergone severe eutrophiction. To check the process of eutrophiction nd to conserve the lke, the lke conservtion progrmme is under implementtion. Though, in-lke conservtion ctivities such s ertion, hypolimnetic withdrwl or iomnipultion re in their initil stge, severl exlke works in the ctchment hve een completed or re ner to completion. These include check on soil erosion through plnttion nd cementing of rods in the ctchment, control to some extent on lekge or overflow of sewer lines y strengthening of sewer line system, house to house connection of toilets with sewer lines, shifting of horse stle from the ctchment re, etc. Tle. Morphometric fetures of Lke Ninitl. S.No. Prmeter Vlue Length (m) 3 Men redth (m) 3 3 Mximum depth (m) 7.3 Men depth (m) 6. Surfce re (h) 6 Ctchment re (km ).7 7 Shoreline (m) 363 Rtio etween lke ctchment nd surfce re : Since the lke is multipurpose in use s mentioned ove, the pulic ttention is focused on wter qulity of the lke. Moreover, the hypolimnetic ertion work hs now strted (temer, 7). The purpose of this pper is, therefore, to provide current informtion on the wter qulity of the lke so tht impct of hypolimnetic ertion on the lke limnology cn e ssessed. MATERIAL AND METHODS To secure dt necessry for ssessing the wter qulity, wter smples were collected from three depths of the lke: surfce (-m), mid (6-) nd ottom wter (>m) from Jnury to Decemer,

2 6. The smpling site ws locted in the limnetic zone of the lke s shown in Fig.. Smples were collected t monthly intervls. The surfce wter smples were tken directly in wide mouth polyethylene jrs, while the deeper wter smples were collected y Vn-Dorn type deep-wter smpler. The temperture, hydrogen ion concentrtion (ph) nd dissolved oxygen were recorded in the field y YSI wter qulity monitoring system (6- XL, YSI, USA). Bio-chemicl oxygen demnd (BOD ) ws mesured y incuting smples in BOD incutor t C for dys following APHA (99). The consumption of oxygen ws determined y dissolved oxygen meter (model YSI- ). Concentrtion of free crondioxide ws mesured y titrtion method. All other chemicl prmeters were nlyzed y microprocessor sed photometer (YSI model-9, U. S. A.). This equipment uses the methods descried in APHA (99). Wter ws directly sujected to the photometer fter mixing the redymde chemicls supplied y YSI, U.S. A. The wter trnsprency ws mesured y lck nd white Secchi disc, ttched with mesured rope. Temperture ( C) 6 Jn, 6 Fe. Mr Temperture ( C) - 6- > Figure. Sketch mp of Lke Ninitl showing smpling site. 6 Temperture ( C) - 6- > Figure. Sesonl () nd verticl () vritions in wter temperture of Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). Temperture ( C) Jnury, 6 e Figure 3. Temperture profile during circultion (Jnury, 6) nd therml strtifiction period (e, 7) of the lke.

3 Dt presenttion In order to express the sesonl vritions in vrious prmeters of wter qulity, dt of three depths were treted s three replictes. Mens nd stndrd devitions (S.D.) were computed from these replictes. Likewise, to ssess the verticl chnges in vrious prmeters, dt of months were treted s replictes. Mens t ech depth were clculted from these replictes. Further, dt of ll months nd depths were verged to represent the vlues of vrious prmeters for the whole lke. RESULTS The monthly men wter temperture in the lke vried from 9.7 to.96 C eing minimum in Jnury nd mximum in ust (Fig. ). The temperture generlly followed the pttern to mient temperture. The depth profile of temperture showed tht the lke wter circulted during Decemer-Jnury nd remined thermlly strtified for remining prts of the yer. Verticlly, mximum men temperture of 7. C ws recorded t surfce wter nd minimum of.3 C in ottom wter. During therml strtifiction period (e.g., in e), the epilimnion extended from surfce to 6 m wter depth, the metlimnion ws formed etween 6 nd m depth, while the hypolimnion extended from m downwrds. The exmples of temperture profile during circultion nd therml strtifiction periods re shown in Fig. 3. The Secchi disc reding rnged etween.6 nd.7 m with n nnul verge of.3. m. The mximum reding ws recorded in e nd the minimum in Ferury (Fig. ). The wter ws lkline throughout the yer t ech depth. Sesonlly, the ph rnged etween 7.96 nd.6 (Fig. ). The ph declined with the incresing depth nd the minimum ph ws recorded in ottom wter (hypolimnion) (Fig. ). Sesonlly, the lklinity vried from to 36 mg/l, while verticlly it rnged etween nd mg/l (Tles nd 3). The wter ws hrd throughout the study period; sesonlly, the hrdness rnged etween 9 nd 3 mg/l CCO 3 equivlent nd verticlly, from 33 to 3 mg/l CCO 3 equivlent. The hypolimnetic wter ws generlly hrder thn the remining two lyers. The nnul men vlue of hrdness for the whole lke ws mg/l CCO 3 equivlent (Tle ). The surfce wter hd low concentrtion of CO, however, the vlues incresed with incresing depth with high concentrtion in hypolimnion (Fig. 6). The lke mintined firly high level of dissolved oxygen (D.O.) in epilimnetic zone. Verticl distriution of D.O. showed declining trend with depth nd the hypolimnion showed noxi lmost throughout the yer (Fig. 7). Tle. Sesonl vritions (men S. D., n=3 ) in some prmeters of wter qulity of Lke Ninitl during 6 S. No. Prmeters J, 6 F M A M J J A S O N D Alklinity Hrdness 3 Iron Copper.6. Zinc 6 Mngnese 7 Fluoride

4 Tle 3. Verticl vritions (men S. D., n=) in some prmeters of wter qulity in Lke Ninitl during 6. S.No. Prmeters - m 6- m > m Alklinity Hrdness Iron Copper Zinc Mngnese Fluoride Jn, 6 Fe. Mr Trnsprency (m) Figure.. Sesonl vritions in Secchi disc reding of Ninitl lke during 6. ph Jn, 6 Fe. Mr ph 6-6- > Figure.. Sesonl () nd verticl () vritions in wter ph of Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). Free CO - Jn, 6 Fe. Mr Free CO 6-6- > Figure. 6. Sesonl () nd verticl () vritions in concentrtion of free cron-di-oxide in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men)

5 The iochemicl oxygen demnd (B. O. D.) in the lke wter ws quite high. Sesonlly, the verge B.O. D. vlue rnged etween 9 nd 3.3 mg/l. Verticlly, the vlues of B. O. D. incresed with wter depths nd reched t the level of mg/l in hypolimnion (Fig. ). The concentrtion of phosphte-phosphorus (PO -P) vried mrkedly from one smpling occsion to nother t ech depth. Sesonlly, the vlues rnged etween 9 nd 93 μg/l (Fig. 9 ). The nnul men concentrtion for the whole lke ws 3.7 μg/l (Tle ). The concentrtion incresed with incresing wter depth with mximum men of 6 μg/l in hypolimnetic wter (Fig. 9 ). The concentrtions of ll forms of nitrogen were high with sesonl vritions from.9 to.9 mg/l for nitrte-nitrogen,.3 to.9 mg/l for mmonium-nitrogen nd. to.73 mg/l for nitrite nitrogen (Fig. - ). The concentrtions of ll forms of nitrogen incresed with depth with mximum concentrtions in hypolimnion (Figs. - ). The nnul men concentrtions of nitrtenitrogen, mmonium-nitrogen nd nitrite-nitrogen for the whole lke were.7. mg/l,..3 mg/l nd.3. mg/l, respectively (Tle ). The men concentrtion of fluoride in the lke wter vried sesonlly from.9 to.6 mg/l eing minimum in ust nd mximum in Decemer. The concentrtion tended to increse with depth (Tle 3). The nnul men vlue for the whole lke ws computed to e t.6.3 mg/l (Tle ). The sesonl nd verticl vritions in concentrtions of four micronutrients re presented in Tles nd 3, respectively. Sesonlly, the concentrtions of iron rnged from. to.3 mg/l nd showed decresing trend with depth. The copper content vried from. to.6 mg/l nd showed depth wise distriution pttern similr to iron. The concentrtions of zinc rnged etween. nd.6 mg/l, while the concentrtions of mngnese fluctuted from. to. mg/l (see Tles nd 3). The nnul men concentrtions for the whole lke for Fe, Cu, Zn nd Mn were:.6. mg/l,.39.6 mg/l,.9. mg/l nd..3 mg/l, respectively (Tle ). Tle. Annul men vlues of vrious prmeters for the whole lke ( S. D., n=36 except trnsprency for which n=) in Lke Ninitl during 6. S.No Prmeters Men, S. D. Temp ( C). 3. ph.3. 3 Trnsprency (m).3. Alklinity 6 Hrdness DO.3. 7 BOD. 7.3 Free CO.6. 9 NO 3 -N.7. NH -N..3 NO -N.3. PO -P (g/l) Fe.6. Cu.39.6 Zn.9. 6 Mn Fluoride.6.3 Dissolved oxygen - Jn, 6 Mr Dissolved oxygen - 6- > Figure. 7. Sesonl () nd verticl () vritions in concentrtion of dissolved oxygen in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). 3

6 B. O. D. 3 Jn, 6 Fe. Mr B. O. D > Figure.. Sesonl () nd verticl () vritions in iochemicl oxygen demnd in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). PO -P 3 3 Jn, 6 Fe. Mr PO -P - 6- > Figure. 9. Sesonl () nd verticl () vritions in concentrtion of phosphte-phosphorus in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). NO 3 -N Jn, 6 Fe. Mr NO 3 -N > Figure.. Sesonl () nd verticl () vritions in concentrtion of nitrte-nitrogen in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). NH -N... Jn, 6 Fe. Mr NH -N > Figure.. Sesonl () nd verticl () vritions in concentrtion of mmonium-nitrogen in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men).

7 NO -N.. -. Jn, 6 Fe. Mr NO -N (mg/l) > Figure.. Sesonl () nd verticl () vritions in concentrtion of nitrite-nitrogen in Lke Ninitl during 6 (verticl rs indicte the stndrd devition from the men). DISCUSSION Besides ffecting the metolic ctivities of orgnisms, the het udget of wter ody lso ffects the climte of the re y relesing or retining the het. The uptke of het during summer nd its relese during winter y the present lke clerly indicted its role in regionl climte control. The temperture profile of the lke suggested tht the Ninitl lke is wrm monomictic wter ody displying single circultion period during winter. The nnul men secchi disc reding for the whole lke in Lke Ninitl (.3 m) suggested the hyper-eutrophic nture of the wter ody. The low wter trnsprency of the lke ws minly ecuse of high concentrtion of prticulte mtter nd suspended solids. Light intensity, mount of humic cid nd orgnic solids nd phytoplnkton density could, however, lso ffect the wter trnsprency. It is understndle tht reduced trnsprency hinders the sunlight to penetrte into the deeper lyers, therefore, it my e inferred tht the Ninitl lke sors lesser mount of sun-het thn its cpcity. The low trnsprency will hve negtive impct on the regionl climte; hence, it hs to e incresed considerly. The hydrogen ion concentrtion (ph) of wter ody is generlly controlled y the concentrtion of CO, which in turn is controlled y photosynthetic ctivities of producers (Hutchinson, 97). In lke Ninitl, the wter ws lwys lkline with high ph vlues in epilimnion where the concentrtion of CO ws usully low. In fct, the uptke of CO y utotrophs in epilimnion did not permit the CO to rect with wter forming cronic cid. In deeper wter, lthough the ph ws not cidic, its vlue ws lower s compred to the surfce wter. Perhps, the unutiliztion of CO in hypolimnion resulted into the formtion of H CO 3, which fter dissocition into H + - nd HCO 3 ions reduced the ph there. High ph vlues in the lke wter will hve serious consequences s high ph promotes cynocteri to form looms (Gupt et l., 6) It is worthwhile to mention here tht certin strins of cynocteri my produce iotoxins hrmful to the potentil consumers of the wter (Crmichel, 96). Phillipose (96) ws le to ctegorize the wter odies into three ctegories on the sis of lklinity vlues. According to his criteri, the wter odies hving lklinity vlues from - mg/l re elieved to e nutrient poor, - mg/l re supposed to hve moderte concentrtion of nutrients nd those hving -6 mg/l re sid to e nutrients rich. Bsed on this criterion, the Ninitl lke with its lklinity rnging from to 36 mg/l with n nnul men for the whole of 6 mg/l cn e considered s nutrients rich lke. The ions such s clcium nd mgnesium in comintion with icrontes, crontes, sulphide, sulphtes nd other nions mke the wter hrd (Wetzel, 93). Hrd wters re elieved to e more productive thn the soft wters (Brrett, 97). Hrd wter my lso crete prolems to humn helth cusing gstritis. The nnul men vlue of hrdness for the whole lke in Lke Ninitl (377 9 mg/l) signifies the productive nture of the lke. Since the lke wter is used for potle supply, it is lso of concern to the humn helth. The noxic sitution in hypolimnion, lmost throughout the yer, in Lke Ninitl strongly suggests the hyper-eutrophic nture of the lke (Hutchinson, 97; Ruttner, 963). Since hypolimnion is the ultimte trp of orgnic nd inorgnic sustnces, the B.O. D. ws high over there. The high photosynthetic ctivity kept the epilimnion sturted with oxygen. The high vlue of B.O.D. in ech lyers lso indicted the mgnitude of pollution in the lke. Nitrogen is one of the importnt prmeters relted with the eutrophiction of wter odies. An nnul men concentrtion of NO 3 -N for the whole lke in the present study (.7. mg/l) ws out three times greter thn the vlue set for eutrophiction (. mg/l) y Swyer (966). Potentil sources of NO 3 -N for Lke Ninitl could e precipittion, surfce runoff, sewerge dischrge, drins input, lef litter etc. The nnul men concentrtion of mmonium-nitrogen (NH -N) for

8 the whole lke ws lso high (..3 mg/l), higher thn tht of the nitrte-nitrogen. Ammoniumnitrogen is the preferred source of nitrogen for mny phytoplnkton (Wetzel, 93) ecuse it requires less metolic energy for utiliztion, nd under-limited energy vilility, more growth hs een shown to occur with NH -N thn NO 3 -N s nitrogen source (Cirns et l. 97). This suggests regulr monitoring of NH -N in future investigtions. The low concentrtion of nitrite-nitrogen (NO -N) (men for the whole lke:.3. mg/l) in the present lke signified the low rte of denitrifiction. NO -N is n unstle form of nitrogen nd rpidly reduces to gseous form (Mcgregor nd Keeney, 973) or gets oxidized into nitrte form. The men concentrtion of totl inorgnic nitrogen (sum of concentrtions of NO 3 -N, NH -N nd NO -N) for the whole lke in the present study ws. mg/l, which gin signified the eutrophic nture of the wter ody (Vollenweider, 96). Another importnt prmeter of eutrophiction is phosphorus since it is utilized y micro nd mcroflour in smll mount, nd is the min constituent of denosine-triphosphte (ATP). Severl workers (e.g. Vollenweider, 96; Crlson, 977; Anon, 96) hve considered vlue of > μg/l of PO -P s indictive of eutrophiction. In the present wter ody, the nnul men concentrtion for the whole lke (3.7 μg/l ) ws thirteen times higher thn this criticl limit of eutrophiction. The high concentrtion of PO -P in hypolimnion might e due to unutiliztion of PO -P y iot coupled with noxic sitution there. The potentil sources of phosphorus to the present lke ppered to e () noxic sediments in the hypolimnion, () excretion from high density of mosquitofish, Gmusi holrooki nd (c) externl input from the ctchment. N/P rtio hs lso een demonstrted to e relted with eutrophiction. It is well known tht low N/P rtio promotes the growth of lue-green lge (Crmichel, 96). In the Ninitl Lke, frequent looming of cynocteri is lso relted to the low N/P rtion in the lke (Gupt et l, 6). Micronutrients re of prime significnce to the iot s well s for humn helth, if the wter is used for potle supply. The concentrtions of ll four micronutrients studied, were within the desirle limit of ISI/WHO. The concentrtion of fluoride is lso considered to e n importnt prmeter of wter qulity s its high concentrtion is relted with fluorosis. The nnul verge concentrtion of F for the whole lke (.6.3 mg/l) ws within the permissile limit of WHO. CONCLUSION The present study hs successfully collected the useful dt on wter qulity of the lke. The dt clerly indicte tht the lke is highly eutrophic. Presently, the hypolimnetic ertion to restore the lke hs strted. The future study will help to understnding the impct of ertion process on wter qulity of the lke. ACKNOWLEDGEMENTS This work ws finncilly supported y Ministry of Environment nd Forest (NRCD), Government of Indi nd Uttrkhnd Government under Ntionl Lkes Conservtion Progrmme. Ninitl Lke Region Specil Are Development Authority, Ninitl cted s nodl gency. The uthorities of Kumun University Ninitl helped in smooth running of the project, for which they re thnkfully cknowledged. REFERENCES A. P. H. A. 99. Stndrd Methods for Exmintion of Wter nd Wste Wter. Americn Pulic Helth Assocition, New York. Anon. 96. Wter pollution y fertilizers nd pesticides. Orgniztion for Economic Coopertion nd Development, Pris. Brrett, P. H. 97. Potssium concentrtions in fertilized trout lkes. Limnology & Ocenogrphy,, 7-9. Cirns, J. Jr., Lnz, G. R. nd Prker, B. C. 9. Pollution relted structurl nd functionl chnges in qutic communities with emphsis on fresh wter lge nd protozo. Proceedings of the Acdemy of the Nturl Science of Phildelphi, (), Crlson, R. E A trophic stte index for lkes. Limnology & Ocenogrphy,, Crmichel, W.W. 96. Algl Toxins. Advnces in Botnicl Reserch,, 7-. Gupt, P. K, Tiwri, Priynk nd Gupt, Rgini 6. Cynocteri nd ssocited environmentl fctors in Lke Ninitl, Uttrnchl, Indi. Journl of Ecophysiology nd Occuptionl Helth, 6, 7-3. Hutchinson, G. E. 97. A Tretise on Limnology. Vol I. Geogrphy, Physics nd Chemistry of lkes. John Wiley nd Sons. New York. Mcgregor, A.N. nd Keeney, D. R Denitrifiction in Lkes sediments. Environmentl Letters, 7-. Phillipose, M. T. 96. Freshwter phytoplnkton of inlnd fisheries. Proceedings of Symposium on Algology, New Delhi 99. ICAR Ruttner, F Fundmentls of Limnology. 3 rd edn. University of Toronto Press, Toronto. Swyer, C. N. 97. Fertiliztion of lkes y griculturl nd industril dringe. New Englnd Wter Works Assocition, 6, 9-7. Vollenweider, R. A. 96. Scientific fundmentls of the eutrophiction of lkes nd flowing wters with prticulr reference to nitrogen nd phosphorus s fctors in eutrophiction. Orgniztion for Economic Coopertion nd Development, Directorte of Scientific Affirs, Pris. Wetzel, R. G. 93. Limnology. nd edn. CBS College Pulishing, Phildelphi. 6