Indian Journal of Geo-Marine Sciences Vol. 41(1), February 2012, pp. 90-97 Status of the seawater quality at few industrially important coasts of Gujarat (India) off Arabian Sea Poonam Bhadja & Rahul Kundu* Department of Biosciences, Saurashtra University, Rajkot-360 005, Gujarat, India. *[E-Mail: [email protected], [email protected] ] Received 21 November 2010; revised 24 January 2011 Present study reports the spatial and temporal variations of the seawater quality from five major shores along the South Saurashtra coastline (India). The results suggested normal range of physical, chemical and biological characteristics in the samples of Dwarka and Mangrol as these coasts are not affected by any apparent anthropogenic effects of any kind. The results also suggested considerable anthropogenic load to the coastal waters of three other shores studied where moderate to high degree of industrial activities existed. Results of the present study revealed that the spatio-temporal variations of water quality parameters were considerably affected by anthropogenic impacts at Veraval, moderately at Kodinar and somewhat lesser degree at Diu. [Keywords: Anthropogenic impact; India; Saurashtra coast; Seawater quality; Spatial and temporal variation] Introduction the aquatic system are mainly controlled by the Seawater resources are considered to be one of the fluctuations in the physical and chemical major components of environmental resources that are characteristics of the water body13. The Arabian Sea is under threat either from over exploitation or pollution, considered as one of the most productive zones in the caused by human activities1. Coastal area is the most world oceans14-15. Coastal regions between Okha and dynamic and productive ecosystems and are also foci Bhavnagar is now a hot-spot for mega industries like of human settlements, industry and tourism2. Thus, Refineries, Cement, Chemicals, Soda Ash, Rayon, the water quality plays very important role in well- Power plant, Fertilizer and other supportive being of human, animals and plants inhabiting the industries. This coastline is known for its rich marine area3. The quality of surface water within a region is life especially intertidal biota in its extended intertidal influenced by both natural processes and and subtidal areas16. Present studies therefore, have anthropogenic activities4. Marine water quality has been aimed to set up a seasonal database of standard become a matter of serious concern because of its water quality parameters of five shores along the effects on human health and aquatic ecosystems South Saurashtra coastline which are favourite for including marine life5. Physico-chemical setting up mega industries. characteristics are indeed vital water quality parameters for monitoring due to their instability6, Materials and Methods where significant variations in physico-chemical Saurashtra region is located south-western part of parameters affect the quality of water resources7. Gujarat State (India), part of the semi-arid to arid The proper and meaningful monitoring should Kathiawar Peninsula, and occupies a total coastal include examination of spatial and temporal patterns stretch of 865 km. On an average, it receives 600 to of surface water quality, identification of chemical 700 mm rainfall annually. Dwarka to Diu segment of species related to hydrological conditions and the south Saurashtra coastline stretches for about assessment of environmental quality indicators8-12. 300 km with smooth and straight sandy of rocky- The nature and distribution of the flora and fauna in sandy beaches. The beaches are usually calcareous and dominated by bioclasts, the consolidated ancient __________ equivalent of these biogenic sands are milliolite rocks. *Corresponding Author The milliolite forms the substratum for the beach Phone: + 91 281 2586419, Fax: + 91 281 2577633, 2586419 sands and occur as cliffs, wave cut platforms and BHADJA & KUNDU: SEAWATER QUALITY AT FEW INDUSTRIALLY IMPORTANT COASTS OF GUJARAT 91 submerged dunes, all along the shoreline indicating receives wastes from different sources. The coastal quaternary sea level fluctuations. Tides in Saurashtra area between Kodinar and Veraval is fast emerging as coast are mixed, predominantly semidiurnal type with an industrial hot-spot and few mega industries like a large diurnal inequality. The study was conducted chemicals, cement, polyester etc. are already in on five different stations (Fig. 1) of Saurashtra operation. Mangrol is a small hamlet around 50 km coastline, at Diu (20° 42′ N, 71° 01′ E), Kodinar west of Veraval with predominantly fisherman (20° 46′ N, 70° 46′ E), Veraval (20° 53′ N, 70° 26′ E), population. Dwarka, around 175 km west of Veraval, Mangrol (21° 07′ N, 70° 07′ E) and Dwarka (22° 13′ is a major pilgrim town of India. N, 68° 58′ E). These shores were selected on the basis Each sampling stations were visited monthly and at of their strategic locations, existing industries, least six samples of surface seawater were collected infrastructural facilities for the likelihood of being from different locations of the same coast. However, developed as industrial zones, different anthropogenic the locations for the collection of samples in a activities along the entire coastal area. particular coast were fixed. The study was conducted The South Saurashtra coastline is basically rocky- during November 2007 to October 2008 and the sandy, being rockier in the east and west, sandier in collected data were presented season wise as the the central part and more rocky-muddy in the far weather condition of this part of the peninsular India eastern part. Union Territory of Diu, a small seasonal typically represents the periods of winter (December tourist town, is devoid of industrial and other to February), summer (March to May), monsoon anthropogenic pressures. A little away from this area (June to August) and post-monsoon (September to on the eastern side, the fishing town Zaffrabad, port November). town Pipavav and Asia’s largest ship breaking yard Some physical parameters like seawater Alang is situated. Kodinar is a small town around temperature, pH and conductivity were measured 40 km west of Diu and has large cement factory and a directly in the field using portable multi parameter sugar factory. On the other hand, Veraval is one of the analyzer. Parameters like TS and TDS were largest fish landing site of India situated around determined gravimetrically and samples for DO and 60 km west of Kodinar, surrounded by a Rayon BOD were preserved in BOD bottle and later factory, number of small to medium scale industries analyzed. For the analysis of turbidity, salinity, COD, and 42 fish processing industries. It involves Port calcium, magnesium, sulphate, sulphide, phosphate, activities like transport, boat manufacture and ammonia, chlorophyll and phaeophytin, seawater samples were collected in polyethylene bottles. The analytical procedures for all parameters were adopted from APHA17 and Trivedi and Goel18. The obtained data were subjected to different statistical analyses for their cumulative acceptability. Significance of spatial and temporal variations was compared by using single factor ANOVA. Correlation coefficients analysis was also performed to find out relationship between various water quality parameters within a sampling site. Cluster analysis were conducted to detect multivariate spatial similarities in marine water quality. All statistical analyses were done as per Sokal and Rohlf19. Results and Discussion Temperature is one of the most important factors in the coastal ecosystems, which influences the physico- chemical characters of coastal water13. Since, the sampling sites were on the open sea coastline off Arabian Sea, were situated more than tens of Fig. 1Map showing the locations of the selected shores from kilometers away of each other but shared the common where the sampling was done. open coastline, spatial variations were not evident. 92 INDIAN J. MAR. SCI., VOL. 41, NO. 1, FEBRUARY 2012 The shores are open and continuous without any temperature the pH values also did not show much barrier and thus, normal tidal activities occurred all spatial variations (Table 6). However, slight along this coastline. The seasonal variations in the fluctuations were observed which may be due to local seawater temperature showed similar pattern in all the environmental conditions. Veraval and Diu was sampling sites (Tables 1 to 5). Seasonal fluctuations recorded high pH values (Tables 3 and 5), which may in the water temperature were typical of this area20. be due to high anthropogenic activities in these two The pH of water is important because many biological locations. Veraval is a highly industrialized shore activities can occur only within narrow range21. Like where human interference to the coastline is high Table 1Physico-chemical characteristics of seawater from Dwarka coast. Values expressed are mean ± SD. Parameters Seasons Winter Summer Monsoon Post-monsoon Temperature (oC) 21.22 ± 0.06 25.71 ± 0.10 23.12 ± 0.06 25.16 ± 0.06 pH 8.16 ± 0.01 8.25 ± 0.01 8.23 ± 0.01 8.26 ± 0.01 Conductivity (mS/cm) 17.34 ± 0.07 17.51 ± 0.07 17.49 ± 0.08 17.58 ± 0.05 TS (g/l) 40.05 ± 0.14 40.69 ± 0.09 44.26 ± 0.12 43.56 ± 0.04 TDS (g/l) 39.92 ± 0.21 40.64 ± 0.09 44.20 ± 0.12 43.51 ± 0.04 Turbidity (NTU) 5.08 ± 0.05 5.12 ± 0.01 5.21 ± 0.01 5.18 ± 0.02 Salinity (%0) 32.64 ± 0.04 35.58 ± 0.07 34.31 ± 0.09 35.30 ± 0.08 DO (mg/l) 6.35 ± 0.02 5.67 ± 0.02 6.18 ± 0.03 6.22 ± 0.02 BOD (mg/l) 0.61 ± 0.03 0.64 ± 0.03 0.79 ± 0.03 0.76 ± 0.04 COD (mg/l) 1.01 ± 0.02 0.86 ± 0.02 0.91 ± 0.03 1.00 ± 0.02 Sulphide (mg/l) 0.22 ± 0.01 0.23 ± 0.01 0.26 ± 0.02 0.21 ± 0.01 Sulphate (g/l) 2.62 ± 0.01 2.75 ± 0.02 2.96 ± 0.01 2.75 ± 0.02 Calcium (g/l) 0.42 ± 0.01 0.42 ± 0.01 0.42 ± 0.00 0.43 ± 0.01 Magnesium (g/l) 1.33 ± 0.01 1.32 ± 0.01 1.33 ± 0.00 1.33 ± 0.01 Phosphate (mg/l) 0.07 ± 0.000 0.06 ± 0.001 0.08 ± 0.001 0.06 ± 0.001 Ammonia (mg/l) 0.02 ± 0.001 0.01 ± 0.000 0.02 ± 0.001 0.02 ± 0.001 Chlorophyll (mg/m3) 1.30 ± 0.018 1.10 ± 0.025 1.22 ± 0.014 1.19 ± 0.012 Phaeophytin (mg/m3) 0.14 ± 0.001 0.11 ± 0.002 0.13 ± 0.001 0.12 ± 0.001 Table 2Physico-chemical characteristics of seawater from Mangrol coast.