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Bioaccumulation of Heavy Metals in Aquatic Fauna Collected from Contaminated Waters of the River Karnafuli in the South-East Coast of Bangladesh Kizar Ahmed Sumon1, Al Mamun1, Md. Enamul Hoq2, Md. Wahidul Alam3, Md. Rafiqul Islam Akhand4, Md. Abdus Sattar5, M Abul Faiz6, Harunur Rashid1* 1Department
of Fisheries Management, Bangladesh Agricultural University, Mymensingh, Bangladesh 2Bangladesh Fisheries Research Institute, Mymensingh, Bangladesh 3Institute of Marine Science and Fisheries, University of Chittagong, Chittagong, Bangladesh 4Innovision Consulting Private Ltd., Dhaka, Bangladesh 5Department of Medicine, Chittagong Medical College, Chittagong, Bangladesh 6Dev Care Foundation, Dhaka, Bangladesh *Corresponding
Author: Tel: +88-01924-429971; e-mail:
[email protected]
Abstract The study was intended in determining the levels of some physico-chemical parameters, bioaccumulation of heavy metals in fish, shrimp and snail muscle sampled from the River Karnafuli. Samples were collected from two different points of the Karnafuli River (UPS-upstream the pollution source and PS- Pollution source) during July 2012-January 2013. The samples were collected for two different seasons: the summer and the winter. The samples like one fish species-Goby (Apocryptes bato), one shrimp species- Karnafuli shrimp (Palaemon karnafuliensis) and one snail species- Girdled horn snail (Cerithidea cingulata) were analyzed for the detection of concentration of six heavy meta like copper (Cu), chromium (Cr), lead (Pb), iron (Fe), aluminium (Al) and nickel (Ni). The concentrations of heavy metals in each sample were determined via Atomic Absorption Spectrophotometry. Among the physico-chemical parameters studied the dissolved oxygen concentration was considerably low at pollution source area in winter. Out of the six most hazardous substances Cu, Cr, Pb and Ni were identified in low amount in fish and shrimp but high in snail. These metals were within the safe limit adapted by fish and shrimp. The bioaccumulation of heavy metal concentrations in snail was higher than the other samples like fish and shrimp during both summer and winter. The present study indicates that the water quality of Karnafuli River is deteriorating and the organisms are getting polluted due to discharge of untreated industrial wastes.
INTRODUCTION Bangladesh is a great delta formed by the alluvial deposits of the three mighty Himalayan Rivers: the Ganges, the Brahmaputra and the Meghna. These three rivers originate outside of Bangladesh and flow through China, Nepal and India before they enter into Bangladesh and finally drain out into the Bay of Bengal [1]. The environment, economic growth and development of Bangladesh are all highly influenced by water- its regional and seasonal availability, and the quality of surface and ground water. More obvious are the polluting activities, such as the discharge of domestic, industrial, urban and other wastewaters into the water-course (whether intentional or accidental) and the spreading of chemicals on agricultural land in the drainage basin [2]. Water quality also depends on effluent types and discharge quantity from different type of industries, types of agrochemicals used in agriculture, and seasonal water flow and dilution capability by the river system [3]. Advancement in technology as well as increase in population have led to environmental concerns relating from indiscriminate dumping of refuse and discharge of industrial effluents, petroleum waste water, and crude oil spills replete with most common heavy metals in our environment [4]. River pollution has been a major problem in the developing countries. In developing countries the watercourses are polluted approximately twenty
percent by industrial effluents and the rest by untreated sewage [5]. Heavy metals occur in aquatic systems from natural sources and anthropogenic activities. The pollution of aquatic environment by heavy metals affects aquatic biota posse’s considerable environmental risks and concerns [6]. Compared with other types of aquatic pollution, heavy metal pollutants less visible but its effects on the ecosystem and humans are intensive and very extensive due to their toxicity and their ability to accumulate in the biota [7, 8]. These chemicals accumulate in the tissues of aquatic organisms at concentrations many times higher than concentrations in water and may be biomagnified in the food chain to levels that cause physiological impairment at higher tropic levels and in human consumers [9]. These heavy metals are potential toxic agents for human having effects on nervous system. Nowadays heavy metal pollution is a major problem in developing countries like Bangladesh. The pollution problem is associated with the discharge of different types of effluents from various industries such as garments, textiles, aluminium, plastic, rice mill, fish drying and other industries. The heavy metal pollution of the River Karnafuli is occurring due to the discharge of various contaminants. In this situation, it is necessary to evaluate the presence of trace elements and their limits in fish and plants as well as to human body. The aim of this study is to evaluate the seasonal
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variation in bioaccumulation of six heavy metals such as Cu, Cr, Pb, Fe, Al and Ni in fish, shrimp and snail muscle and the suitability of some physicochemical parameters sampled from Karnafuli River situated in the South-East Coast of Bangladesh. The information will be helpful to create awareness among the people and policy makers about the necessity of installing ‘Effluent Treatment Plant’ in these industries. MATERIALS AND METHODS The study area The River Karnafuli receives different types of effluents those are discharged from the numerous industries like garments, tanneries, rice mills, plastic, aluminium, refineries, ship breaking industries and fish drying industries. The river is getting polluted rapidly due to indiscriminate and unplanned construction of these industries. As a result the water and the different organisms like various species of fishes, shrimps, snails and other invertebrates of this river are getting toxic (Fig. 1). A.
UPS PS
discharge near at Bolihater Khal, Karnafuli River and Pollution Source (PS): Apparently high industrial discharge near the mouth of Chaktai Khal, Karnafuli River. C.
Sample preparation The collected samples were put in ice box and transported to the Wet Laboratory at Fisheries Faculty, Bangladesh Agricultural University, Mymensingh. Samples were kept at 40C until analysis. Viscera were removed from fish samples and the shell was discarded from shrimp and snail samples. The samples were prepared following the standard protocol. 3-5 g of each sample was kept in an oven at 60 0c for 48 hours. After then1 g was taken in digestion tube. The samples were digested with 15 ml acid mixture (10 ml HNO3 and 5 ml HClO4) at 1200 C for 1 hr. Digested samples were then filtered with Whitman 42 filter and raised the volume to 100ml with distilled water. D.
Sample analysis The physico-chemical parameters (pH, dissolved oxygen, total alkalinity, ammonia-nitrogen and temperature) of water were analyzed using HACK kit. The prepared fish, shrimp and snail samples were analyzed by Atomic Absorption Spectrophotometer (AAS) for the detection of heavy metals like Cu, Cr, Pb, Fe, Al and Ni. E.
Data analysis Data were analyzed using a two-way analysis of variance (ANOVA), the level of significance thereby being set at 5% (probability limit of p< 0.05). RESULTS AND DISCUSSION A.
Fig. 1. Map showing the sampling locations; upstream the pollution source (UPS) and pollution source (PS) of the River Karnafuli.
B.
Site selection and sample collection The River Karnafuli was selected as the case study for this research. Fish, shrimp, snail and water samples were collected from July, 2012 to January, 2013 to determine the toxic substances and the water quality parameters. These samples were collected within two seasons, the summer and the winter. Fishes- Goby (Apocryptes bato) and shrimpsKarnafuli shrimp (Palaemon karnafuliensis) were collected with seine net. Snail samples- Girdled horn snail (Cerithidea cingulata) was collected manually. Immediately after collection the fish, shrimp and snail samples were kept into the ice box. The high density bottles were used to collect and preserve the water sample. The samples were collected from two points of the Karnafuli River. The sampling points were: Upstream the Pollution Source (UPS): About six kilometers from pollution source. Low industrial
Water quality parameters Water quality parameters sampled from two sampling points are shown in the Table 1. Results showed that there were considerable variations in water quality parameters between two sampling points. The values indicated that water pollution level was higher at pollution source area (Chaktai Khal) than upstream the pollution source area (Bolihater Khal). This may be due to the variation of different industries and discharge of untreated wastes. Table 1. Mean concentrations (±SE) of physico-chemical parameters collected from two sampling points of Karnafuli River Sampling Point Parameter UPS PS pH 8.62 ± 0.18 8.76±0.12 Dissolved oxygen (mg/l) 6.285±0.32 0.67±0.66 Total alkalinity (mg/l) 60.5±4.50 77.0±7.0 Ammonia-nitrogen (mg/l) 0.61±0.44 3.0±0.1 Temperature (0C) 24.75±4.45 24.4±4.0
The suitable range of DO, total alkalinity, NH3-N and pH for fish in river is 6.5-7.0, 20-200,
