IMPACT OF PETROLEUM HYDROCARBONS ON THE COMMUNITY STRUCTURE OF PLANKTON IN THE COASTAL WATERS OF SAURASHTRA (GUJARAT, INDIA)

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1 Electronic Journal of Environmental Sciences Vol. 7, (2014) ISSN: (Available online at Original Article Indexed in: ProQuest database Abstract, USA ( ProQuest Science journals, Techonology Research database, Illustrata Technology, Environment Science collection and Health and Medical complete), EBSCO databases (USA), Indian Science abstract. IMPACT OF PETROLEUM HYDROCARBONS ON THE COMMUNITY STRUCTURE OF PLANKTON IN THE COASTAL WATERS OF SAURASHTRA (GUJARAT, INDIA) NAIR, A., 1 DESAI, I. 2 AND SURESH B. 1 Department of Zoology, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara L; 2 N. V. Patel College of Pure and Applied Sciences, Vallabh Vidhyanagar, Anand E. mail: suved9@hotmail.com Received: April 17, 2014; Accepted: May 19, 2014 Abstract: The degree of Petroleum hydrocarbon contamination has been studied and its impacts on the community structure of plankton from the intertidal zone of three study stations of the Saurashtra coast was analyzed. The water samples were tested for petroleum hydrocarbons and biochemical oxygen demand by employing the partition gravimetric method and five day BOD test respectively. Independent group analysis of variance was performed to test the difference between the means for all the parameters. The relative contamination levels were also assessed at the study stations. We observed temporal variation in the PHCs and BOD values in all the stations and as expected the values were found high for Alang Sosiyo and Veraval. It was observed that higher concentration of PHCs in the coastal waters seems to impart its adverse affect on growth of the phytoplankton and zooplankton population as evidenced by the low diversity values observes at Veraval and Alang. Moreover, at Alang Sosiyo, the contamination by petroleum hydrocarbon was found to adversely influence the plankton community as exemplified by the results of Tukey s honest significant difference test. However, since several macro-plankton are known to adapt well to change in environment, further long term follow-up studies need to be conducted to consolidate the present notion. Key words: Petroleum hydrocarbons, Plankton, Coastal waters, Saurashtra? INTRODUCTION The analysis of plankton community structure is evolved as an effective tool in monitoring spatiotemporal changes in the chemistry of marine water and also in detecting the sources of diffused contaminants such as petroleum hydrocarbons (PHCs) in seawater. It is now well established that petroleum hydrocarbon is one of the major contaminants that jeopardize the life in ocean. However, the oceans have long been considered as the ultimate sink, and have been used as major repositories of anthropogenic waste [1]. Nevertheless, in ecological term, all these pollutant induced distresses change the diversity of the biotic component thereby bringing unprecedented alteration in the community structure of the marine ecosystem. India is no exception, with a 19

2 huge infrastructure in petroleum industries and being acknowledged for having the second largest ship breaking yard in the world, the impacts of PHCs on the marine biota hardly gain any concern. Hydrocarbon pollution especially the oil spillage is considered to be a major pollutant in the Indian coastal waters and falls in the top category of pollutant as classified by the United Nations Environment Programmes. The problem is all the more pertinent for a state like Gujarat where the ever mushrooming petroleum industries along the Saurashtra coast might radically influence the hydro-physical, hydrochemical and hydro-biological parameters of the coastal water. Ship breaking, substantial fishing fleets and tourisms were the additional causes of hydrocarbon release in the coastal regions of the Saurashtra. Alang Sosiyo ship scrapping yard is world s largest ship breaking zone, with an annual turnover of around 1.3 billion US dollars [2-4] and is located on the western coast of Gulf of Cambay. Its highest tide (average ~ 13m) and gentle slope with rocky bottom makes this area tailor made for floating ships right up to the scrapping yard, with minimum investment. There is a progressive annual increase in the activity. Statistical data up to March 2002 reveal that about 3600 ships (approximately 400 ships per year) mainly cargo vessels, oil tankers, passenger lines and warships having million MT light dead tonnage (LDT) were beached in a span of twenty years [4]. Substantial fishing fleets and tourism were also cited as the major cause of hydrocarbon release in the coastal regions of the Saurashtra [3]. This was more prominently noticed in the coastal waters of Veraval and Diu. The hydrocarbon compound that enters the marine environment affects a number of abiotic factors as well as the physical and chemical properties of the compound itself. The plankton may be at a greater risk than the other biotic components of the marine ecosystem, due to the proximity to hydrocarbon compounds floating on the Sea surface and their general sensitivity to the toxic components in the hydrocarbons. Therefore, the current study was envisaged wherein the influence of PHCs on essential physicochemical parameters were computed to understand the former s influence on the Electronic Journal of Environmental Sciences 20 community structure of coastal plankters. Study Site: Study was carried out at three stations from the entire intertidal stretch of the Saurashtra coast. The study area was selected considering the tidal influence as well as the reported levels of pollution load [4] in a manner such that first site is considered pristine with least pollution, second moderately polluted and the third highly polluted. The coastland of the Saurashtra stands out as a distinct geographical region with an Island Diu lying off the South coast of Gujarat along the Kathiawar peninsula (Position: N 21 34' 308 and E 72 09' 991 ) and is selected as station one with minimum or no pollution. The second station, Veraval is located in the open coast of Arabian Sea. This is considered as the intermediate fair whether port (Position: N 21 52' 945 E 70 21' 231 ). The third station Alang Sosiyo (Position: N 21 34' 308 and E 72 09' 991 ) is situated on the western coast of Gulf of Cambay. This is designated as the second largest ship breaking yard in the world and was established in the year The three areas receive terrestrial organic input from various sources. Diu being recreational spot, dumps treated or partially treated sewage waste, other solid fitters like plastic canes directly into the sea. In Veraval fishing is the main occupation with about 42 fish processing industries, generating huge amount of organic pollutant and domestic waste. Alang is the largest ship scrapping yard. This produces immense toxic wastes which directly or indirectly enter in the coastal waters of Gulf of Cambay [5]. In 2001, Greenpeace International found heavy metal deposition also in sediment samples in the near shore stations at Alang Sosiyo and concluded that the area is typically polluted [6]. However, no adequate studies had been undertaken, in the other two stations Diu and Veraval, regarding the hydrocarbon pollution in the intertidal zone and its affect on the ecology and biodiversity of flora and fauna. Though such studies are important, presumably one expect a fair degree of contamination in the intertidal zones of the two

3 Nair et al. areas also. Regrettably, the problem of hydrocarbon pollution in Gujarat state has not received considerable scientific attention despite its possible severity on the marine biota. Hence, the present paper aims (1) to gauge the petroleum hydrocarbon contamination along with organic load in the intertidal waters of the three selected stations of Saurashtra coast and (2) to evaluate the effect of PHCs on the community structure of planktons in the coastal waters of Saurashtra. MATERIAL AND METHODS The investigation in the present study was carried out from December 2003 to December The locations of the sampling stations, in coordinates, were predetermined after a reconnaissance survey and their positions identified on site using a handheld Global Positioning System (Garmin, GPS 12XL). At each station namely Diu, Veraval and Alang Sosiyo the sampling for physicochemical and biological parameters were done from the surface zone of the littoral or the low tide region of the intertidal area. The seasonal samplings for pre monsoon, monsoon, post monsoon and winter were performed. Estimation of petroleum hydrocarbons: Partition-Gravimetric method as described in Standard methods [7] was employed to quantify the PHCs. Briefly, to 400 ml of filtered seawater sample 10 ml of hexane was added. The sample was shaken vigorously for 5 to 6 minutes until the layers of water and oil got separated. The filtrate was passed through a separating funnel to extract out the oil floating at the top of aqueous layer. The aqueous layer and small amount of organic layer formed were removed through the separating funnel. The petroleum hydrocarbon dissolved in the solvent hexane was extracted; 10ml of this hydrocarbon extract was collected and was transferred in to totally dry glass vessel. In the same sample, 10ml of hexane was added again along with one scoop of sodium sulphate anhydrous, to remove any moisture content left in the hydrocarbon extract. The extract was transferred into water bath having temperature of 50 C. The extract of petroleum hydrocarbon was heated till 20mL of this sample got reduced to 10mL. After reduction in the volume, the hydrocarbon extracts were passed through silica gel followed by a hexane wash. The extracted hydrocarbon was transferred to a quartz cuvette and absorbance was measured at 105nm in UV- VIS spectrophotometer. Biochemical oxygen demand (BOD): During the present study, the BOD was estimated by employing the 5-Day BOD test as described in the treatise Standard methods for water and waste water analysis [7]. Sampling and quantification of plankton: Surface samplings of plankton were made by filtering 100 litres of water through a bag net of pore size 70μm for phytoplankton and 200μm for zooplankton. The zooplankton and Phytoplankton samples were analyzed for both qualitative and quantitative variables. Subsequently the plankton diversity was computed using Shannon formula (H ). Statistical Analysis: Prior to statistical analysis, all variables were tested for homogeneity by comparing means. After asserting the normality of the data for all variables, Independent group Analysis of Variance followed by Tukey s honest significant difference (HSD) tests between chemical variables (PHCs/BOD) and biological variables (phyto/zooplankton diversity) was performed to test the difference between the means for all the parameters. The statistical analyses were done using the programme Origin Ver. 7 RESULTS AND DISCUSSION The average values of seasonal fluctuations of PHCs and results of one way analysis of variance (ANOVA) followed by Tukey s honestly significant difference (HSD) tests between chemical variables (PHC/BOD) and biological variables (Phytoplankton/ zooplankton diversity) are presented in Table 1. The higher percentage of PHCs values and BOD were documented at Alang Sosiyo. The present observation suggest that at Alang Sosiyo, the ship scrapping industry and its associated waste in the form of heavy 21

4 Electronic Journal of Environmental Sciences metals, petroleum hydrocarbon and biological contamination could be the reason for such a hike in the mean values of PHCs and BOD at Alang Sosiyo. There also occurred a visible sheen of oil on water surface, suggesting that petroleum inputs are derived from the external activities like ship breaking and removal of the ballast and thereby oil residues are washed into the sea. Table 1 shows that the mean values of zooplankton and phytoplankton population with that of PHCs were significantly different at 0.05 levels of p value at Alang Sosiyo, while the difference was not significant at the other two stations viz., Diu and Veraval. The concentration of PHCs at Diu showed reasonably low values. The concentration varied from 22.08mg/L to a maximum of 26.4mg/L, a slight increase during pre monsoon season. The BOD also showed a similar hike during pre monsoon and monsoon seasons of the year. The PHCs concentration at Veraval followed more or less similar trend during pre monsoon and monsoon seasons of the year. 22

5 Parameters Phytoplankton Diversity DIU VERAVAL ALANG SOSIYO Zooplankton Diversity Nair et al. Table 1: One-way analysis of variance (ANOVA) followed by Tukey s honest significant difference (HSD) tests between chemical variables and biological variables. Yes* = The means are significant at P 0.05 level. NS= Not significant Phytoplankton Diversity (H ) Zooplankton Diversity (H ) Phytoplankton Diversity (H ) Zooplankton Diversity (H PHCs NS NS NS NS Yes* Yes* BOD NS NS NS NS NS NS Table 2: Petroleum hydrocarbons (PHCs) and Biochemical Oxygen Demand (BOD) values during different seasons at three stations viz Diu, Veraval and Alang Values are expressed as mean ± SE; n = 5 Seasons PHCs mg/l BOD mg/l Diu Veraval Alang Sosiyo Diu Veraval Alang Sosiyo Winter ± ± ± ± 3.68 ± ± 0.04 Premonsoon 26.42± ± ± ± ± ± 0.75 Monsoon ± ± ± ± ± ± 0.58 Postmonsoon ± ± ± ± ± ± 0.23 Explanation of figures: Fig. 1 (a-c): Layout of the comparison of the petroleum hydrocarbon concentration and BOD during the four seasons at Diu, Veraval and Alang Sosiyo Fig. 2 (a-c): Response of zooplankton diversity to varying concentration of petroleum hydrocarbons during different seasons at Diu, Veraval and Alang Sosiyo Fig. 3 (a-c): Response of phytoplankton diversity to varying concentration of petroleum hydrocarbons during different seasons at Diu, Veraval and Alang Sosiyo 23 However, winter and post monsoon seasons were characterized by low hydrocarbon concentration. An increase in the level of BOD was observed during monsoon, though winter and post monsoon showed a definite decrease from 3.68 to 2.87 mg/l (Table 2 and Figure 1). The levels of biochemical oxygen demand and PHCs at Alang Sosiyo also exhibited significant fluctuation during different seasons. The PHCs concentration varied from 26.2mg/L to a maximum concentration of 29.4mg/L during pre monsoon season. The BOD also followed the same trend as that of PHCs. As with an increase in PHCs content during pre monsoon, there observed a concomitant rise in BOD up to 4.73mg/L. The minimum concentration of 3.45mg/L was observed during the post monsoon whereas during monsoon maximum BOD value was observed. Since, many other biologically

6 degradable organic matters may be washed into the sea during monsoon the rise in BOD level of coastal water during this season is no surprise. The pre monsoon relatively represented the lowest phytoplankton and zooplankton density at all the three stations. However, the observations of Srinivas and fellow workers [3] for the seasonal variations in PHCs concentrations were contradictory suggesting, the concentrations of total PHCs and PAHs are about three times higher in the winter and two times in the monsoon or summer at Alang Sosiyo and about twice in all the other seasons. The response of the plankton community and its diversity towards the petroleum fractions were also similar, though its intensity varied at all the study stations. The annual diversity value for plankton was found maximum at Diu with the diatoms dominated over the dinoflagellates suggesting a greater tolerance of diatoms to PHCs contents in the seawater. This was followed by Veraval. However, Alang exhibited a low diversity of phytoplankton with elevated hydrocarbon contents from its ship breaking activities along with heavy loads of sewage as well as other inorganic wastes. This principally helps to sustain centric diatoms like Thalassiosira and Coscinodiscus sp. Furthermore, the graphical representation (Figure 2 and 3) illustrates that zooplankton diversity has not responded to increase in petroleum hydrocarbon, in Diu, even with significant increase in hydrocarbon concentration in pre monsoon, the site showed greater diversity. The overall zooplankton diversity showed similar values. Varying sensitivities to pollutants among zooplankton species could cause changes in community structure by affecting variables such as rate of increase, rate of predation, mortality and population density [8, 9]. In place like Alang Sosiyo where ship breaking activities are performed at a very large scale, single factor cannot be considered as the cause of ecological damage, various refuse and disposal materials are also discharged and spilled from the scrapped ships that gets mixed with sediments at the coast and finally gets washed into the waters creating a menace. The other two stations Diu and Veraval also provide a clear indication of the seriousness of the impacts of multifarious compounds in Electronic Journal of Environmental Sciences 24 plankton population. Besides, some of the sturdy forms e.g. Cocinodiscus, Rhizosolenia and Thalassiosira had proliferated well and were retained in high numbers. This could be attributed to the presence of nutrients like nitrates and phosphates present in the dispersants or the sewage along with PHCs in the coastal waters as opined by Batten and co-workers [10]. In the present study some of the tolerant species like Sagitta enflata and Sagitta sp. were seen at the coastal waters of Alang Sosiyo. In Veraval, Foraminiferans and Gastropods were abundantly proliferated. Amphipoda and other sensitive taxa however, were absent. Reports indicate that copepods are sensitive to mixtures of different types of pollutants [11, 12]. Uye [13] has also reported reduction in copepods due to excessive release of nutrients in the coastal waters. Providentially, the topographical features of Alang Sosiyo allow excellent mixing and flushing conditions of water during high tide in its coast. The wind induced coastal currents in Alang Sosiyo also keeps this water well aerated thereby retaining enough oxygen and moderate BOD levels except during some seasons. These conditions are helpful in brining dispersion of organics and other pollutants thereby reducing the severe pollution stress as one has expected. Hence, certain species of phytoplankton and zooplankton proliferate well in such waters. This could be further used as a measure to detect environmental disturbances prevailing at Alang Sosiyo. Lower species diversity and propagation of certain species of phytoplankton have been used as markers for some ecological disturbance caused due to anthropogenic compounds prevailing at Kulai regions of Karnataka coast [14]. At Diu the less contaminated and fairly stress free conditions of water abode high diversity of micro flora and fauna. This implies an improved quality of the water and prevalence of a healthy community. The other factor that might contribute significantly to the variations in a marine ecosystem is the tidal influx. The hydrocarbons dissolved or dispersed in water due to tidal influx can easily reach out to the most delicate flora and fauna of the marine ecosystem.

7 Nair et al. The information about the effects of oil on plankton is much sparser than for the littoral and benthic organisms. Generally, plankton is thought to remain rather unaffected by oil, mainly for its capability to escape the contaminated area of the water. This is partially true for larger zooplankton and in case of small scale hydrocarbon pollution in seawaters. Further, oil is reported to affect the seashores and bottoms more rather than the open water ecosystems [15, 16]. The recovery and return of the pristine quality of the coastal waters in this location might take a prolonged period. It is likely that more studies are needed to understand and identify the long term consequences of the contaminants including petroleum hydrocarbons on the aquatic biodiversity. REFERENCES [1] Ian, R.W., Bell, R.G. and Wilkinson, D.L.: Ocean Disposal of Waste water. In: Advanced series on Ocean Engineering, 8. World Scientific Publisher, London, U.K. (1993). [2] Tewari, A., Joshi, H.V., Trivedi, R.H., Sravankumar, V.G., Ragunathan, C., Khabhaty, Y., Kotiwar, O.S. and Mandel, S.K: In: Marine Pollution Bulletin, 42, pp (2001). [3] Srinivas, M.R., Shaik, B., Joshi, H.V. and Ramachandraiah, G.: Chemospfer, 61(11): (2005). [4] Gujarat Maritime Board, Alang-Sosiya port officer. Personal communications (2003). [5] Srinivas, R.M., Shaik Basha., Sravan Kumar,V.G.,Joshi, H.V and Ramachandriah, A.: Marine Pollution Bulletin, 48: (2004). [6] Khantak, J. and Jayaraman, N.: Environmental contamination in Alang Sosiyo Ship Scrapping Yard,Gujarat, India: A study report in ship scrap III: steel and toxic waste for Asia, Green Peace Publishers, Germany, pp 1-33 (2001). [7] APHA, AWWA. Standard methods for the examination of water and wastewater. American Public Health Association, Washington DC (1998). [8] Sprules, W.G.: J. Fish. Res. Bd. Canada, 32: (1979). [9] Allan, S.E., Smith, B.W. and Anderson, K.A.: Environ. Sci. Technol., 46: (2012). [10] Batten, S.D., Allen, R.J.S. and Wotton, C.O.M.: Marine Pollution Bulletin, 36: (1998). [11] Ramaiah, N. and Nair, V.R.: Indian J. Marine Sciences, 26: 20 (1997). [12] Gajbhiye, S.N., Mustafa, S., Mehta, P. and Nair, V.R.: Indian Journal Marine Sciences, 24: (1995). [13] Uye, S.: Hydrobiologia, 292(293): (1994). [14] Tiwari, L.R. and Nair, V.R.: Indian J. Mar. Sci., 27: (1998). [15] Robertson, A.: Petroleum hydrocarbons In: AMAP Assessment Report: Arctic Pollution Issues, Arctic Monitoring and Assessment Programme (AMAP), Oslo, Norway: /42 (1998). [16] Almeda, R., Wambaugh, Z., Wang, Z., Hyatt, C., Liu, Z., and Buskey, E.J.: PloS one, 8(6): e67212 (2013). 25