Dynamics and Quantification of Dissolved Metals in a Highly Contaminated River-Estuarine System
Total Page：16
File Type：pdf, Size：1020Kb
Indian Journal of Geo-Marine Sciences Vol. 44(9), September 2015, pp. 1310-1322 Dynamics and quantification of dissolved metals in a highly contaminated river-estuarine system S.C. Asa1, S.N. Bramha2, A.K. Mohanty2, T.K. Bastia1, D. Behera1 & P. Rath1* 1 *School of Applied Sciences, Department of Chemistry, KIIT University, Bhubaneswar, Odisha. 2Radiological Safety and Environmental Group, Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy, Govt. of India, Kalpakkam-603 102, Tamil Nadu, India. *[E-Mail: [email protected]; [email protected]] Received 04 July 2014; revised 11 September 2014 Dynamics of heavy metals such as Fe, Mn, Co, Ni, Cu, Zn, Cr, Pb and Cd in surface water of Brahmani river-estuarine system were studied taking 25 samples from different sampling locations along the complete stretch. Irrespective of season, Fe was most abundant in both river (avg. 260.15 µg / l ) and estuarine (avg. 119.9µg / l) samples, whereas Cd (avg. 1.59 µg / l) and Co (avg.1.55µg / l) were the lowest in the river and estuarine samples respectively. The average concentrations of all the dissolved metals were much higher than the world river average. The average concentrations Cr and Cd for the river were above the criteria of maximum concentration (CMC) as prescribed by US Environmental Protection Agency. Results of factor analyses revealed that anthropogenic contributions were the source for the increase in dissolved metal concentrations. Canonical discriminate function indicated that it was moderately successful in discriminating the groups as predicted. River Brahmani with an annual discharge of 18.58 x 10 m carries 6.907 x 10 tons of total heavy metals into Bay of Bengal and the calculated rate of erosion in the basin is 176.582 kg km year. [Keywords: Dissolved metals, Enrichment ratio, Metal Pollution Index, Discriminate analysis, Factor analysis] Introduction Rivers play a major role in assimilating changes such as dissolution, precipitation, heavy metals from both natural sources through sorption, complexation etc, which affect their erosion, weathering of source rock and bio-availability6. anthropogenic sources such as urban sewage Though many works have already been carrying domestic wastes, effluents from reported pertaining to geochemistry, hydro geo- different industries, washings from agricultural chemistry and water quality of Brahmani River7- fields containing fertilizer and pesticides1 and 12, most of those studies focused on small from mining areas through various ways such as stretches of the river or some specific areas and mine discharge, run-off, dissolution of rocks and in addition concerned with physico-chemical soils, wet and dry fallout of atmospheric parameter of river water and metal distribution particulate matter etc2-4. in sediments. No attempt has been made so far Metals such as Cu, Zn etc are essentially regarding dissolved metal distribution along the required by different living species in water complete stretch of the river including the bodies. However nutritional requirement of estuary and near shore area. In the present study, these metals substantially differ from species to concentrations of some selective heavy metals species and that is too in a narrow range. (Fe, Mn, Co, Ni, Cu, Zn, Cr, Pb and Cd) in Exposure to elevated concentration of metals surface water of Brahmani river-estuarine may result in serious consequences such as death system were measured. A quantitative approach of certain species. High levels of heavy metals has been made by the use of enrichment ratio, also cause metal accumulation by aquatic metal pollution index (MPI) and through organisms affecting the species higher up in the comparison with standards for surface water food chain. In addition some metals like Cr, Cd, quality and levels for the same in other studies Pb etc are highly toxic even at very low level5. of India and World. Individual metal loads were In river water metals exist in two forms i.e. also calculated. Multivariate statistics such as suspended particulate and dissolved forms. factor analysis was applied for meaningful data During transportation they undergo numerous reduction and interpretation of results. ASA et al.: DYNAMICS AND QUANTIFICATION OF DISSOLVED METALS IN A HIGHLY CONTAMINATED RIVER-ESTUARINE 1311 SYSTEM Discriminate analysis was performed for Table 1 Anthropogenic scenario of the basin discrimination of sampling sites with respect to the measured parameters. Industry Product/s Water Pollutants Waste Consumption water [m3/ day ] generated Materials and Methods [m3 / day ] Agricultural Fertilizers, 405.6 M Brahmani River is the second largest river in run-off pesticides, m3/year 2 Odisha having drainage basin of 39,035 km - - nutrients, SS,TDS, area with total length of 800 km and peak heavy metals discharge of 22,640 m3 s-1. It mixes with River Industrial & Oil, grease, 90,000 Urban heavy Baitarani to form Dhamara estuarine system townships, metals, - - before meeting the Bay of Bengal. Brahmani major urban nutrients, SS, centers and TDS River receives effluents from most of the major conglomerates industries of Odisha located in Rourkela, Angul, Rourkela Steel Iron and Steel 2,65,580 Heavy 1,20,000 Plant [RSP] metals, SS, Talcher and Jajpur Industrial areas, washings oil, grease from mines located in Angul-Talcher belt and RSP Fertilizer 28,807 Nutrient, 7,920 [CAN] Heavy metal Sukinda, sewage from a number of major Fertilizer Fertilizer 45,883 Heavy 16,608 townships along with agricultural runoff from its Corporation of [Urea] metals, SS, India oil, grease catchment area. As a result, the river water does NALCO Aluminium 5,066 4,900 not represent a healthy aquatic ecosystem. The [Smelter] NALCO [CPP] Electric 1,35,000 90,000 detailed basin status with respect to source of power generation of waste water, volume of waste ORICHEM Ltd Na2Cr2O7, 170 10 Basic water generated, water consumption by major Chromium industries, important pollutants is summarized in Sulphate, Yellow Table 1. The basin lies in an Indian shield that sodium consists of Pre-Cambrian rocks such as granites, sulphate Talcher Electric 13,227 6,483 gneisses, quartzites, schists of Eastern Ghats, Thermal power power amphibolites, pegmatites, khondalites and Talcher Electric 1,37,099 52,080 Thermal Power power charnockites and Gondwana rocks like shale, Plant, NTPC, Heavy sandstone and coal11. This basin of Odisha is of Kaniha metals, SS, MESCO Iron Iron and Steel 84,840 oil, grease 40,078 high environmental importance due to the Steel Ltd. presence of mangrove forest ecosystem, Bhusan Steel Iron and Steel 2,29,200 1,08,274 Ltd. Bhitarakanika National Park, a Wild Life Brahmani Steel Iron and Steel 84,840 40,078 Sanctuary which has been listed as a RAMSAR ORIND Steel Iron and Steel 16,800 7,936 site in 2002, crocodile breeding centre and the Ltd. Neelachal Steel Iron and Steel 1,75,200 82,764 Olive Ridley nesting beaches. This basin also Ltd. has a considerable potential for development of Jindal Steel & Iron, Steel - - Power and Electric inland fisheries in reservoirs, ponds, tanks and Power canals. Mines: Coal, iron and - - In order to monitor the dissolved metal chromite mines concentration, water samples from 25 stations were collected along the complete stretch of the eight are from saline water zone which includes river between Feb-May (dry season) and July- estuary and coastal sea up to a distance of 3 km Oct (wet season) as shown in Figure 1. Out of from shore. Stations were selected on the basis these stations 17 are from fresh water zone while of location of major industries, municipal- township discharge points and also on accessibility to the sampling sites. In each station sampling was carried out for five times during the sampling period and average value was taken for evaluation. Surface water samples were collected from the mid stream of the river and at a depth of 20-30 cm from water surface. To minimize the contamination from boat 1312 INDIAN J. MAR. SCI., VOL. 44, NO. 9 SEPTEMBER 2015 Figure 1 Map showing sampling locations wherever used and also from the surface, the and accuracy of the methods were systematically samples were collected by travelling in upstream and routinely checked by analyzing standard direction. Acid cleaned, dried polythene solutions procured from Merck after desired containers were used for this purpose. dilutions. After collection pH was measured Multivariate statistical analysis was performed immediately by a portable battery operated pH through factor and Discriminate analysis meter (Elico- Model No. DI-707). DO was techniques16,17. Factor analysis was performed measured by Winkler’s titration method. One on correlation matrix of rearranged data of the liter of river water was filtered through 0.45 mm dissolved metal concentrations, pH and DO. The Millipore cellulose nitrate filter paper using a variance and factor loadings of the variables vacuum pump. The filtered water samples were with eigen values were computed. Stepwise acidified by concentrated HNO3 to bring down Discriminant analysis using Wilks’ method was the pH around 2.0, so as to inhibit adsorption of carried to investigate differences between the metal ions on to container surface and to prevent groups on the basis of the variables of the cases, metal precipitation. The concentrations of Fe, indicating which variables contribute most to the Mn, Co, Ni, Cu, Zn, Cr, Pb and Cd metal ions in group separation and in addition to test the the pre-concentrated solutions were determined theory whether cases are classified as predicted. with the help of Atomic Absorption Data were processed using routines taken from Spectrophotometer (AAS) model Perkin Elmer Statistical Program for Social Sciences (SPSS- 1025. Pre-concentration was made by non- Version 20.0) statistical software. boiling evaporation13 except for samples taken from saline water zone where chelating solvent- Results and Discussion extraction technique was adopted.