Trends irr Li& science^ (lndiar) 1991 ,6 , (1) ; 29-34

Impact of pollution on the hydrobiological features of the Estuaries in Madras region 4 K, 0. JOSEPH, J. P. SRIVASTAVA* and Z. HODA*

Central Institute of Brackishwater Aquaculture, 1 2 Leith Castle Street, Santhonze, Madras-600 028

*Post-Graduate Department of Chemistty, Magadh University, Bodh Gayo-824 234

SUMMARY The studies revealed that the quality apf water

The Pulicat lake, Adyar and Ennore estuaries are some of the major brackish wader ecosysteins in

the neighbourhood of Madras cit) dzferering slightly i n their physiognomy. All there are kr.ootl to be ~rooiding nursery areas f i r a t~rtnlber o f cornrncr-

cially important prawns and Jirhts. Due to fast industrialisation and urbenisalion some of t/~ese

estuaries arc getting Polluted by the inpuxion of sawoze and industrid wastes. The Adyar ertuar~, 2-eceives untreated cig sewage and industrial efluents while Ennore estuary mainb wastes from pelroche-

micnl complex and thermal power plant. The present

study mas conducted to assess the impact of @oIlutiov

on these ecosystems by hydrochemical and biological

features that existed during 1984-85.

wn.c degraded in Adjar and Ennore estuaries from tile filheries as well as f r l~m the public health point of vidw. On the other hand, the Pulicat lake, whzch is situahd in the outskirts of Madras ci l j zvac free from indushial or sewage pollution. The quatum of plankton which serves as a jkh food for most of the commercially important species zebus less in ila)ar compared to ot'ler estuaries The bottom faunal components, ahundar~ce of post-loroat and commercial jtish landingr u,ere also minimum i n Adyar showing the marimrim impact o f pollution on this ecosystem. S~ggeslions for the i;nprooernent of existing conditions are gisen to help augment j s h production.

Kep iVordr : Pulicat Lake, Adyar Eltua- ries, Ennore Estuaries, Prawns, Fishes.

Introduetion et al., 1988; Joseph, 1988, 1989, 1991). With the growing interest in prawnbased cornmer-

Due to the influx of large quantities of urban and industrial wastes. some of the cia1 aquaculture in the brackishwater areas

coastal areas particularly adjoining the large in 'he coastal states (Alagarswami, 1990 a

cities of India are getting polluted (Qasim study on the sewage and industrial pollution

impact has a n important practical application. Not only they are important in the interest of water quality but also essential from the view point of product acceptability in the aquacul- ture industry. Under these circumstances, it was felt worthwhile to examine the pollution impact on Adyar, Pulicat and Ennore estuaries around Madras.

The Adyar estuary receives untreated city sewage and industrial wastes while Ennore estuary mainly wastes from petrochemical complex and thermal power plant. The lake Pulicat, which is situated in the outskirts of Madras city, is free from industrial or sewage pollution,

Materials and Methods

From three selected stations of lake Puli- eat, Adyar and Ennore estuaries samples of water were collected at monthly intervals during the period 1984, 85 and analysed accor- ding to standard methods (A. P. H. A., 1971). Bottom fauna, plankton, prawn and fish larvae were also collected simultaneously from the same stations and analysed following the methodology given by Jhingran, et. al., (1970). Fish catches were recorded from the main landing centres every month and computed for annual landing.

Observations and Disc~ssion

Results of hydrochemical analysis are given in Table 1. The mean surface water tempe- ratures in Pulicat, Ennore and Adyar estua- ries were 31.3, 30.7 and 32.1 '6 respectively. The waters of these estuaries exhibited highly variable salinity condition which depends upon rain, drought, temperature and evapo- ration. The closure of estuarine bat mouths

caused an increase in salinity conditions during summer months. The average dissol- ved oxygen content in the Pulicat lake and Ennore estuaries were 7.6 and 5.0 mg. 1-I respectively. The level in Adyar estuary was low with values which are less than the criti-

cal level of 3.0 mg. 1-"(Tarzwell, 1985). This clearly indicates that pollution was cons- picuous in this estuary,

The pulicat and Ennore estuarine waters were alkaline in reaction, while the Adyar water was acidic in nature during most of the months. A sh~f t in pH values more on the acidic side was noticed in the Adyar estuary when compared to the values of pH reported earlier by Chacko, et al , (1954). This decr- ease in pH was ma~nly due to the ever incre- asing sewage effluxion and less dilution by sea water owing to prolonged bar mouth clo- sure due largely to low flow, small streams and precipitation pattern that are very chara- cteristic in this part of the country. I n addi- tion tidal amplitude is also low. The fish kills in Adyar estuary observed during summer months (May-June) may be due to the syner gistic effect of low pH, low dissolved oxygen, high temperature and salinity.

The higher concentrations of phosphate and total alkalin~ty in Adyar and Ennore indicate the effect of industr~al and sewage waste effluxion and the flux of nutrients thro- ugh them into these estuaries. The nitrate content dld not show any pollution trend in

these two estuaries, though the concentrations are slightly higher than those of other estua- ries on the east coast of India (Nair, ct. al., 1987; Aziz and Nair, 1980).

The higher chemical oxygen demand

POLLUTION AND ESTUARIES OF MADRAS 3 1

TABLEI. Hydrochemicall features of PuQicat, Ennore and Adyar estuarine waters (average values are given in parenthesis).

Parameters Pulicat Ennore Adyar

Water Temp. O C

Salinity, 10-8

Dissolved cxygen, mg. 1-n

PW

Total alkalinity, mg. 1-1

Phosphate

Nitrate

Chemioal oxygen demand

Biochemical oxygen demacd (BOD,)

(COD) and biochemical oxygen demand (BOD) test results observed in Adyar and Ennore were indicative of organic pollution in these ecosystems. The observed values in these estuaries are higher than that observed in polluted Hooghly estuary [Basu, 6t. a1 , 1970), but lower than that observed in pollu- ted Mahim Creek (Jussawala, 1980).

basis (Table 2). Zoo-plankton counts in the Ennore estuary (100 U 1-I) and the Adyar (50 U.I-') showed lower values than that of unpolluted Pulicat (420 U. 1-I): It is clear that an ideal biological condition existed in the Pulicat Lake where the quantitative and qualitative abundance of plankton was found to be greater compared to that of Adyar and Ennore. Considering the plankton population, the impact of pollution was maximum in Adyar followed by Ennore.

The general trend of the phyto-plankton concentration in Ennore (982 units 1-I) and Adyar (555 U 1 - l ) showed lower values than that of Pulicat (1233 U.1-1) on an average In lake Pulicat, the dominant groups of

32 JOSEPH, e l . a!.,

TABLE-2. Range and average density of phyto and zoo-plankton (units 1"l) in Pulicat, Ennorc and Adyar estuaries.

Biotopes Phyto-plankton Zoo-plankton Dominant forms Range Average Range Average

PuIicat , 160-5160 1233 200-640 420 Naoicula, Plumrosigma, Nitzschia, Diblonie~, Oithona, Acartia, Digptotnur, Hypnca, hnte- romorpha, Chastarnorpho and Gascinodisrus.

Ennorc 160-2600 982 82-120 100 Nazitula, Hypneo, Oithona, Oscillotoria and Brachiunus.

-

Adyar 120-2160 555 40-80 50 Plurrosigma, ~Va~icula , Spirulina, Hypnea, Oithona and Brachionus.

bottom fauna were polychaetes, tanids, amphi- pods and molluscs. Sea anemones, nemato- des, chironomid larvae and miscellaneous crustaceans from the groups of minor impor- tance. Almost all groups were present in all the seasons except chironomid larvae which are seen in large numbers during monsoon months of October and November fmonthly data not given). Bottom fauna were poorly represented from the Adyar and Ennore colle- ction centres. Gastropodes, polychaetes, my- sids amphipods, juveniles of prawns and fishes and chironomid larvae were recorded from Adyar and Ennore estuaries.

Velon drag net collections (Table 3) bro- ught in a variety of fishes, prawns and carbs in unpolluted Pulicat while there were only few in the Ennore and Adyar estuaries. The minimum biomass observed in Adyar further confirms the deleterious effect of aquatic pollu- tion, which was found to be maximum in Adyar estuary.

The existence of poor biological conditions in Adyar and Ennore indicated the presence of pollution in sublethal level which may not immediately kill or seriously effect the adult fishes, but may cause mortality of fish-food organisms; fish-eggs and larvae. The present study shows that larval population and fish food organisms of there two estuaries get dest- royed by the pollutants. The synergistic effects of pollutants have caused fish mortality in Adyar where at tlrnes the pollution load exceeds the sublethal level and becomes toxic.

The highly productive and uncontamina- ted nature of the Pulicat lake is confirmed by the fishery potential~ty of the system. There was a continuous and regular fishery through- out the pmod under observation. Further, the lake supported a fairly good fishery of commercially important prawns and mullets and ~ t s annual landings were estimated to be over 1,000 tonnes per year (Table 4). This

POLLUTION AND ESTUARIES OF M A D R A S 93

TABLE-3. Results of velon net sampling in the Puii- clearly indicated that the trend in fishery was cat, Adyar and Ennore Estuaries. more or less steady or on the increase as there

was no decline from the total catches sepor- Wet Weight in mg. ted for earlier years (Raman, et. B E . , 1977).

Estuaries Prominant Species - - -------- Range Avg- TABLE-4. Total fish catch (in tonne~) from the

P~ilicat, Adyar and Ennore estuaries

Puiicat Fishes :- during 1984 and 11985.

Sphyroena, G'rres, Pcrio- jlhalrnus, Gobius, Tetra- Year Estuaries --------- Average don, I~iognalhus, T d r a - 1984 1985 dun, Ambasis, Lulianus, - Mu&, Siia,oo, and Sigonus. 105-210 188 Puiicat 1126 1012 1069

Prawns :- Ennore 152 116 154

Penoaus indicus, P . semi-

sukatlrs, ~ f ~ t a ~ a n o c u r Dobsonil B Macrobra- chiurn.

Crab :-

Adyar 46 42 44

--

The assessment of the effects of environ- mental pollution on fisheries by analysing the trends in catches alone is not advisable. This

Charybdis is due to the fact that various factors are res-

ponsible for yearly changes in fisheries pro-

Ennore Fishes :- duction. These include impoverishment of fishing grounds due to over fishing, advance-

Leiognathus, Lutionus, Coronx, Afilochialus Ail-

ments in the field of fishing techniques and ~ ~ i i ~ T6tro~3n 56-136 98 gears and changes in the hydrochemical con-

dition of the environment. However, the Prawn :-

M. dobsonii

Crabs :-

M ~ g a l o p s and Thala~ni ta

impact of pollution on fisheries can be better assessed from reports of direct damage (fish mortality) and also by examination of trends in catches.

- In Ennore the fish catch reported during

Adyar Fishes :- 1963 was 340 tonnes (Evangeline and Subbiah, 1968). The present annual average landing

Mu&, Sillago, Gerre~, was found to be oniy 134 tonnes. This dec- Gobius and Thoapon 27-45 39

line in fishery can be attributed to, among Prawn :- other factors, the pollution effects of adverse

Macrobrachiurn env~ronmental changes caused by industrial

and sewage wastes in Ennore estuary.

3.2 JOSEPH ct. a!.,

The decline in fishery was more pronoun- ced in Adyar. The total catches estimated during 1963 was 216 tones (Evangeline, 1968) and the present annual average landing (44

tonnes) is only 115 of the earlier catches. This steep decline in fisheries and episodal fish kills observed during summer indicated maxi- mum pollution hazard in Adyar estuary.

of cn~ironment, (B. Patel, ed.), W i h y Ea$lnn limilrd Arm Dclhi, 431 pp.

BASU, A. K.,B. B. GHOSH and R. N. PAL, 1970. 3. W a t . PoNut. Contr. Fed. 42 (101, 1771-178'1.

CHACKO, p. I , R. SRINIVASAN, S. GEORGE and T. B. RAMACHANDRAN, 1954. Conlr. F i ~ h Biol. Sln. dfadras, 1 , 36 pp.

EVANGELINE, G., 1968. MadrasJ. Firh, 4, 50-69.

EVANGELIPU'E, G. and K. SUBBIAN, 1968. Ibid. 5,

The observations made on the Adyar and Ennore estuaries clearly indicate that it is

necessary to evolve methods of treatment of effluents for each major type of pollutant and the water quality standards under estuarine condition should be laid down for abatement of pollution from the fisheries point of view.

ACKNOWLEDGEMENTS

The first author is grateful to Dr. K. Alag- arswami, Director, CIBA and late Dr. A. V. Natarajan, former Director of GICFRI, for their valuable guidance,

References

ATLAGARSWAMI, K., 1990. In : Aquaculrurr in Asia (bl. Mohan Joaeph, ed.), Asian Fishrries Sabty,

Indian Branch, 190 pp.

A. P. H. A,, 1971. 13 Ed. Amcr. Pub. Hllh. ASJOG, Arm

York, 874 pp.

AZIZ, A. P. K, and N. B. NAIR, 1980. Managemenl

JHINGRAN, V. G., V. GQPALAKRISHNAN, P. RAY and A. GHOSH, 1970. Proc. Tndo Pacif. Fish. Coun., 14th Session, IPFCI7, 7O(S, YM, 31,

37 PP. JOSEPH, K. 0 , 1980. In : PTOC. 8th flat. Symp. Life

Sci. (A.K. Saxeaa and V. L. Saxcnn, Eds.) Manu Publications. Kanpur, 13-21.

JOSEPH, K . Q., 1989. Proc. Nut. Acad. Sci. India, 59, ( B ) , 1 , 45-50.

JOSEPH, I<. 0.. 1991. Indian J. Mar. Sd., (in press)

JUSSAWALA, D. J., 1980 In : Proc. Sam. Manag~ment ofEnz~iron., B . Patel, ed.) BARC, Bombay, 11-29.

NAIR. N. B. , M. ARUNACHALAM, P K. A. AZIZ K. KRISHNAKUMAR and K. DHARMARAJ, 1987. Proc. Nal. Acad. Sci. India, 57, (B), 7-18.

QASIM, S. Z., R. SENGUPTA and T. W. KUREI. SHY, 1988. Proc Indian Acad. Sci., 97, 117-131.

RAMAN, K., M. KAEIYAMURTHY and K. 0. JOSEPH. 1977. J. Mar. Biol. An. India, 19, ( 1 and 2), 16-20.

TARZWELL, C.M., !958. Itch. Rcpt. W., Taft Sanitary Eng:necrin~ Centre, Cincinnati, Ohio, 62pp.