Indian Journal of Marine Sciences Vol. 10. June 1981. pp. 189-191

Microbiological Studies in the Mandovi- System

ANURAGINI ROW National Institute of Oceanography. Dona Paula. 403004 Received 3 November 1980; revised received 3 January 1981

Total heterotrophic and coliform bacteria were surveyed during Oct. 1977 to Sept. 19'78 from 9 stations each along the rivers Mandovi and Zuari and 3 along the coast of Goa. Total heterotrophic population showed wide temporal and spatial variations and ranged from I x 10' to 5 x 10·, The ratio of coliforms to aerobic heterotrophs indicated that the extent of pollution was very low. Mandovi and Zuari estuaries are tidal stream estuaries 0.1 g; agar 14 g in 1000 ml of filtered sea water, pH being predominantly influenced by sea water inflow. adjusted to. 7.8)8. Counts were made after 24 to. 48 hr Annual contribution of sewage to. Zuari and Mandovi incubation at room temperature. These counts river systems is 4.67 x 106 and 5.21 x 106 m 3 indicate the level of readily available organic matter in respectively. Industrial discharge amounts to. 4.4 x 106 the water. Counts of coliform bacteria (which indicate m 3/year fo.r· Zuari and 0.8 x 106 m 3/year for recent sewage pollution) were carried o.ut by the most Mandovi ': probable number method? using multiple tubes of Variation of heterotrophic bacterial population and MacCo.nkey Broth and reading the results from the presence of coliforms in the estuaries are McCrady's Tables, after 24-hr incubation at 37cC. reported! -6. Matondkar et at. 7 have studied the Monthly variations in the total heterotrophic seasonal variation of heterotrophic bacteria in the bacteria in Mandovi River, are shown in Fig. 2. Counts mang.ro.ve swamps along the Mandovi-Zuari river varied between 8 x 104 and 250 x 106/ml. Counts of systems. However, no. information on the monthly coliforrns (Table I) varied between 0 and 1100/100 ml. variation of total heterotrophic bacteria or presence of In the Zuari River, the total heterotrophic counts (Fig. coliforrns in these rivers is available. Hence, the present 2) varied between 3 x 104/ml and 241 x 106/ml. investigation on distribution and monthly variation of Coliforrns (Table I) varied from 0 to. 1100/100 ml. total heterotrophic bacteria and coliforms in Mandovi Yearly mean values of aerobic heterotrophs do. not and Zuari estuaries has been made. show any significant variation in the density of Nine stations were fixed in each o.f the 2 rivers and 3 population from the mouth to. the source of the rivers. stations along the coast (Fig. I). These stations were This indicated that the heterotrophs were highly considered on the basis of probable penetration o.f salt tolerant to. changes in salinity (Table 2). Ratio. of water front and consequent tidal influence and their coliforrns to. aerobic heterotrophs was very low, nearness to. the areas o.f mining, industrial and indicating the absence o.f pollution in both the rivers. domestic activities. The total distance covered by the 9 stations was 67 km in Zuari and 65 km in Mandovi, Of these, 2 stations were worked in the 17 km long Canal, connecting the 2 rivers at distances o.f 14 and II km respectively from their openings into. the sea. The 3 coastal stations covered a distance of 32 km between Baga o.n the north and Colva on the south. N Samples could not be collected from the coastal stations during monsoon as this area was inaccessible. Between Oct. 1977 and Sept. 1978, samples o.f water 15 20' were collected by boat o.nce every month over a period ARABIAN of 12 hr at a mid-depth of each station along the 2 SEA rivers as well as along the coast. Samples were collected in sterile glass bottles with screw caps and stored in an ice-box until they were analysed in the laboratory. Counts of aerobic heterotrophic bacteria were carried out by the po.ur plate method using marine agar (Zo.bell's 2216E, peptone 5 g; yeast extract I g; FeP04 Fig. 1- Station locations

189 11000 -----. 1100110011004601100110024011001502828150150150M243210-4601100110011001509015093110011001100110075150152321011004110011001100110011001100110011001100M90Z2Z-,Z4Zs000011004300110015MjMeM4MsM6!Z6Z7ZeZ9900M71501100110015150902402379751502103920210110010075775110011002101100159309323475 1100Il0U1100·24043-O·-00 000404 000000 460 11000 93157 r 1100 10, 1981 ... June INDIAN J. MAR. SCI. VOL JUNE • 4(1 Table 1-MonthlyMarchAprilJulyAug.Sept.Sept.Aug.JulyDec.Feb.MarchNov. Varialions of Coliforms (organisms/lOa m!) at Different19781977Oct. Stations in Rivers Mand6vi (M) and Zuari (Z) JuneproductionMay is. I I00/ I00 !Ill and minimum where all 3 tubes read negative is zero M, Z, Jan.1978 'Rea9ings taken from McCrady's table where the maximum number1977 of coliforms for 3 positive McConkey broth tubes showing acid and gas I

z:> 6 ..•:IIII ~87556 5 9, B

65

I A Vearl, ••••••.• lu•• 55 ilt--+r:p 8 Molltfltt,•.••.••,••

COASTAL REGION 9 7·0656·05·5 '"' A 8 "j mt-1 H-~TRIVER27262825 ZUAIlI II 0 N 24

P.I

NDFMJJASIi 29

Fig. 2 Variations 10 aerobl( heterotrophs

190 SHORT COMMUNICATIONS

These studies indicated that the rivers Mandovi and Table 2-Annual Mean Heterotrophic Bacteria and Salinity Zuari, along with a stretch of coastal area of G6a, are in Mandovi and Zuari relatively free from human influence on their water quality. 5t 149150145.526.36086.475.134.129.14956\.40.03641.50.04No.(2\.0510.1246.714.829.28Bacterial34.314.40.38 24.536.82515.359.718.8552.3Salinity2.9Salinity8.975.4 x12.653.22\.8150.7Mandovi106)/0/00 loomIZuari 89467253 No.No.(100 mlx 106)/ Bacteria The authors thank Dr S.Z. Qasim for his valuable I comments. Grateful thanks are due to Dr R. Sen Gupta, for his leadership, keen interest and encouragement. Thanks are also due to Mr N.B. Bhosle, for the valued help and suggestions and to the Central Board for the Prevention and Control of Water Pollution for providing financial support for the study.

References

I Technical Report No. 2/79. National Institute of Oceanography. Goa. 2 Covill R W. Symposium on the Forth-Tay estuaries in Proc Royal Higher values of coliforms observed at some stations Soc Edin. 71B (1972). may be due to localized contamination6• 3 Shimmin K. Proceedings of the conference in the matter of Density of microbial number in all coastal stations pol/ution of the navigable waters of Pearl Harbour and its was high compared t9 the rivers (Fig. I). The counts tributaries in the state of Hawaii. Honolulu. Sept (1971) 64. varied between I x 104/ml and 500 x 106/ml (Fig. 2). 4 Mikhaylenko L. Ye Khoroshikh L A & Dukhovnaya E I. The density of coliforms was relatively low. but were Iiydrobiol JI. 13 (1977) 37. 5 Roper M M & Marshall K C. Aust J mar freshwater Res. 29 present during September (150, 1100 and 9/100 ml (1978) 335. respectively at sts CI, C2 and C3), October and 6 Anson A E & Ware G C. J applBact. 37 (1974) 657. November (1100/100 ml at all stations). This may be 7 Malondkar S G P. Mahtani S & Mavinkurve S./ndian J mar Sci. due to the very recent flushing of water from the 9 (1980) 119. 8 Oppenheimer C & ZoBell C E. J mar Res. 11 (1952) 10. estuaries into the sea, at the time of sampling. Samples 9 APHA. Standard methods/or the examination 01water and waste collected during the rest of the months did not show water (American Public Health Association, Broadway. the presence of coliforms, since coliforms die rapidly in New York. 19 N Y) 1975. sea waterlO. 10 Mitchell R, Water Res. 2 (1968) 535.

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