INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, Copyright by the authors - Licensee IPA- Under Creative Commons license 3.

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1 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, 2014 Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0 Research article ISSN Distribution and Seasonal Variation of Trace metal concentration in Surface sediment of Dhamra Estuary. East coast of India Barik S.K 1, Panda C.R 2 1- KIIT University, Bhubaneswar 2- Institute of Minerals and Material Technology (IMMT), Bhubaneswar bariksaroj@yahoo.co.in doi: /ijes ABSTRACT The Dhamra estuary is a major tropical estuary in the east coast of India which hydrographical characteristics are mostly governed by monsoon. A study was carried out to find out the trace metal concentration in the sediments of. Dhamra estuary. The concentration and distribution of selected trace metals in surface sediments of the Dhamra estuary were studied to determine the extent of anthropogenic inputs from mining activities and to estimate the effects of monsoon on geochemical processes in this tropical estuarine system. Analysis of bulk sediments from the Dhamra estuary shows that concentrations of Copper,Cobalt, iron, manganese, Cadmium, chromium, zinc and lead vary from mg/kg, mg/kg, %, %,0-1.2 mg/kg, mg/kg, mg/kg and mg/kg respectively. An important observation is that, in general, The lowest metal concentrations are found during the monsoon and the premonsoon compared to the postmonsoon.the enrichment of Cadmium, Chromium and Manganese reflects the intensity of corrosion resistance paints are used in ship and traller, which creates Cadmium contamination. For various metals the geoaccumulation index (Igeo) has been calculated to assess the degree of pollution in sediments. This shows that Cd, and Cr moderately contaminated the sediments.igeo value of Cadmium,2 mg/kg higher value in the post monsoon in the down stream region of estuary than in the monsoon and premonsoon seasons and of Chromium 1.47 mg/kg) was higher value in the premonsoon in the st-6 than in the monsoon and postmonsoon. Keywords: Trace metals, surface sediment, Dhamra estuary, anthropogenic input, Seasonal. 1. Introduction The Dhamra Estuary is a tropical Estuary on the East Coast of India and its hydrological characteristics are governed by monsoon regime. The Dhamra Estuary is located on the east coast of India. The location of Dhamra Estuary in close proximity to the mineral belt of Orissa, Jharkhand and West Bengal. Sheltered between the main land and the Kanika Sand Island on the eastern coast. The mining activities in this region may influence the biological and geochemical conditions of the estuarine waters to considerable extent..the measurement of trace element concentrations and distribution in the marine environment leads to a better understanding of their behaviour in the aquatic environment and is important for detecting sources of pollution. The trace metal data provide new information on the surface sediment geochemistry in the region whilst the study of element interrelationships, including organic carbon, gives information on their possible origin(alagarsamy,1991),the distribution of metals in sediments at 8 stations(fig.)in the Dhamra Estuary has been examined, therefore,inhance the data inventory for the region Received on March 2014 Published on April

2 characterize the geochemistry of Fe,Cd,Cr,Mn,Zn and Pb in the surficial sediments and to help understand the influence of anthropogenic activities and monsoon on biogeochemical process in this tropical estuarine system.these impacts were assessed by means of the geoaccumulation index (Muller,1979) and Igeo classification is reported based on the chemical analysis of the bulk sediments. The Igeo has been widely utilized as a measure of pollution in Freshwater(e.g Muller,1980,Singh et al,1997, Kralik,1999) and marine sediments( e.g.stoffers et al,1986,breyan 1992 and Dickinson et al,1996), 2. Material and methods 2.1 Collection and Treatment of Samples: Sampling was carried out monthly, over a period of one year from January to December However the data are presented as pooled values covering premonsoon (February-May), Monsoon (June-September) and Post monsoon (October-January) Seasons. Surface Sediments were collected monthly using a Van veen Grab from 8 stations in the Dhamra estuary(fig.1) across the upper mid and lower regions, Covering a distance of 40km. For total metal analysis, the sediments were dried at C in an oven and disaggregated in an agate mortar, before chemical treatment. For element analysis, the known quantity (~0.2 g) of the powdered samples were digested with a mixture of concentrated HF HNO3 HClO4 for the total metal content (Tessier et al. 1979), The OC was determined by exothermic heating and ~with potassium dichromate and concentrated H2SO4, followed by titration of excess dichromate, with 0.5 N ferrous ammonium sulfate solutions (Walkley, A. and Black, I.A.1934) Figure 1 showed Study area and sampling site. 2.2 Analysis of Trace Metals: Trace metal concentrations ( Co,Cu,Fe,Cd,Cr,Mn,Zn,and Pb ) were measured using an Atomic absorption spectrophotometer(aas,shimadzu,aa-6300)the accuracy of the analytical procedures was assessed using the certified reference material BCR-1 and yielded results within the reference value range(flanagan,1973) For Co,Cu Fe,Cd,Mn,Cr,Pb and Zn the reproducibility. 3. Result and conclusion 3.1 Distribution of Trace Elements: Iron (Fe) The Iron concentration in ranges between 0.88 % and 6.33 % are somewhat higher than that reported from other Indian estuaries. During the post monsoon period higher concentrations of iron are observed throughout the estuary. The station-4 represents higher concentration of Iron, which may attributed that it located on downstream of river, which contribute continuous flow of minerals from upward stream of river. Lead (Pb) The lead concentration varied from 0.8 to 18 mg/kg.lead occurs in nature at an average crustal abundance of 16 mg/kg.like soil in the terrestrial system sediments are the primary sinks for lead in the aquatic environment. For deep ocean sediments the natural average value about 47 mg/kg but with wide fluctuations(craig,1980),lead values in bay, estuarine and other coastal sediments(marsh sediments) have been much altered by man s activities. The average Pb level in Indian river sediment is about 14 mg/kg (Dekov et al, 1999),Which is lower than the world average. The average Pb in Indian river particulates 1016

3 ^51 mg/kg (Dekov et al, 1999),which are also lower than the world river particulates of 150 mg/kg (martin and maybeek, 1979), Figure 1: Map Depicting Sampling Locations for Sediment Quality Assessment Over Dhamra Estuary. Zinc (Zn) The Zinc concentration varied from 71.1 to 90.8 mg/kg.during post monsoon period higher concentration of zinc arises throughout the estuary, generally in this period water depth is less as compared to monsoon, concentration of metals is higher. Zinc can enter the aquatic environment from a number of sources including industrial discharges, sewage effluent and runoff. Manganese (Mn)- The Manganese concentration varied from to %. During monsoon period lower concentration of Manganese arises in station -1.At this location Brahmani and Baitarani river are mixed with each other. In monsoon period due to rainfall its diluted the concentration of metal present in bottom sediment. Cadmium (Cd) The Cadmium concentration varied from 0 to 1.2 mg/kg.during post monsoon period higher concentration of Cadmium arises in station-5.generally in the post monsoon period depth is less than other seasons. Due to more fishing activity with a number of fishing traller and a constructible port is very nearer to it, where small ship are engaged for construction work. In which corrosion resistance paints used, It is the source of toxic Cadmium enrichment in this area. Chromium (Cr)-The Chromium concentration varied from 78 to mg/kg. During premonsoon period higher concentration of Chromium arises in station -6.This station is situated on the downstream of river. 1017

4 Table 1: Seasonal variation of trace metal levels Figure 1: Seasonal variation of trace metals collected during sampling period 3.2 Index of geo-accumulation Possible sediment enrichment of metals was evaluated in terms of the Igeo of Muller (1979), The formuala used for the calculation of Igeo is : log2 ( Cn/1.5*Bn), where Cn is the measured content of element n, and Bn the elements content in average shale (Turekian and Wedepohl,1961), The geoaccumulation index (Igeo) was originally defined by Muller (1979) for a quantitative measure of the metal pollution in aquatic sediments (Ridgway and Shimmield,2002),For Dhamra estuarine sediments, the Igeo values were given in the Figure-3. The elevated identified for Cd and Cr in the same areas indicate that surface sediments are moderately contaminated, most probably as a result of anthropogenic activities. Igeo value calculated for Cd (2 mg/kg) showed higher value in the postmonsoon period in the downstream region of the estuary than in the monsoon and premonsoon seasons. This trace element is attributed to fishing activity. A number of fishing traller,fishing boat and shipping activities for the transport of material for the constructible Port was carried out which is very nearer to sampling points of 1018

5 the estuary. The sediments of the Dhamra estuary were found to be enriched in Cd. Chromium (Cr) was shown more in pre-monsoon season according to the Igeo classification (Table-2), Table 2: The lego classification for assessment sediment quality 3.3 Pollution Load Index (PLI) : Tomlinson et al. (1980) had employed a simple method based on pollution load to assess the extent of pollution by metals in estuarine sediments. Sediment pollution load index was calculated using the equation: CF= Cmetal /Cbackground PLI =ⁿ (CF1 CF2 CF3.CFn) Where, CF is the contamination factor, Cmetal is the concentration of pollutant in sediment Cbackground is the background value for the metal n is the number of metals. The PLI>1 is polluted whereas <1 indicates no pollution During the present study the pollution load index (PLI) was found to be more during premonsoon period followed by post-monsoon and least observation was made during monsoon periods. It is probably due to more dredging activities during pre and post monsoon period than monsoon periods as depicted from the table Comparison of present data with other Indian estuaries Many of the Indian estuaries are not polluted due to their well flushing rate. The trace element of element of estuarine systems were also possesses a sharp seasonal gradient which implies the role of bio-geo-chemical cycling of that particular estuary. During the present study Cobalt was found to be less as compared to the concentration values gathered from other Indian estuaries. The heist values for manganese were found in Godavari Estuary where the present study exhibited very low values (0.1) as compared to the values of other Indian estuaries. Lead concentration was found similar with Godavari Estuary (Ramesh et al., 1990), The iron concentration was found to be more or less similar with Ganges estuary, (Subramanian et al, 1988), Krishna Estuary (Biksham and Subramanian, 1988), Godavari Estuary (Ramesh et al., 1990) and Narmada estuary (Biksham and Subramanian, 1988), The trace metal zinc showed higher concentration in Tapti and Ganges estuary followed by Dhamra estuary. Zinc is commonly used as in paints that are used coloring of boats. 1019

6 Table 2: Seasonal variation of pollution load index in the study area Figure 3: Lego index of Cd, Cr, Pb, Fe, Mn and Zn Table 4: Comparison of metal levels The elevated Igeo values for Cr and Cd in the Dhamra estuary indicate that the surface sediments are Moderately contaminated to some extent, probably as a result of anthropogenic sources of metals entering the coastal zone through river Inputs. It is observed that lowest metal concentrations are found during the monsoon and post monsoon compared to the pre-monsoon. The comparison of the metal levels in the 1020

7 different areas of the estuary indicated that there is a detectable anthropogenic into the Dhamra estuary. Correlation with organic carbon has allowed understanding the distribution of metals and its association within the sediments. It is proposed that continuous monitoring and further studies in the area should be carried out in the near future to ascertain long-term effects of anthropogenic impact and to assess the effectiveness of minimizing the human activity to upgrade the marine environment in the Dhamra estuary on the east coast of India as the mining activities influence the geochemical process in the estuarine systems. 4. References 1. Alagarsamy, R., (1991), Organic carbon in the sediments of Mandovi estuary, Goa. Indian Journal of Marine Sciences 20, pp Biksham, G., Subramanian, V., (1988), Elemental composition of Godavari sediments (Central and Southern Indian Subcontinent), Chemical Geology 70, pp Dekov, V.M., Subramanian, V., Van Grieken, R., (1999), Chemical composition of riverine suspended matter and sediments from the Indian sub-continent. In: Ittekkot. 4. Dickinson, W.W., Dunbar, G.B., McLeod, H., Heavy metal history from cores in Wellington Harbour, New Zealand. Environmental Geology 27, pp Flanagan, F.J., (1973), 1972 values for international geochemical reference samples. Geochemical Cosmochimica Acta 37, Förstner, U., Wittmann, G.T.W., Metal pollution in the aquatic environment. Springer-Verlag, Berlin Heidelberg, p Muller, G., (1979), Schwermetalle in den sediment des Rheins Vera nderungen seitt Umschan 79, pp Ramesh, R., Subramanian, V.,Van Grieken, R., (1990), Heavy metal distribution in sediments of Krishna river basin, India. Environmental Geology Water Science 15, 207-2) 8. Ridgway, J., Shimmield, G., (2002), Estuaries as repositories of historical contamination and their impact on shelf seas. Estuarine, Coastal and Shelf Science 55, pp Subramanian, V., Jha, P.K., Van Grieken, R., (1988), Heavy metals in the Ganges estuary. Marine Pollution Bulletin 19, pp Tessier, A., Campbell, P.G.C., Bisson, M., (1979), Sequential extraction procedures for the speciation of particulate trace metals. Analytical Chemistry 51, pp Tomlinson, D.C., Wilson, J.G., Harris, C.R. and Jeffrey, D.W., (1980),Problems in the assessment of heavy metals in estuaries and the formation pollution index. Helgoland Marine Research, 33, pp

8 12. Turekian, K.K., Wedepohl, K.H., (1961), Distribution of the elements in some major units of the earth s crust. Bulletin Geological Society of America 72, pp Walkley, A. and Black, I.A.(1934), An examination of the Dethreff method for determining soil organic matter and a proposed modification of the chromic acid titration method Soil.Sci. 27, pp