THE ASSESSMENT OF CONTAMINATION LEVELS AND BIOAVAILABILITY OF CADMIUM HEAVY METALS IN SAGULING RESERVOIR SEDIMENT

• Main Author: WARDHANI NIM 35314002, EKA
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26880
• Institution: Institut Teknologi Bandung

This study aims to assess the quality of sediment due to Cd pollution and the bioavailability of heavy metals in the sediment of Saguling Reservoir. Sediment quality assessment uses the Contamination Factor (CF), Geoaccumulation Index (I-geo), Metal Pollution Index (MPI), and Potential Ecological Risk Index (PERI). The Assessment of the bioavailability of Cd is using the Risk Assessment Code (RAC) and Global Contamination Factor (GCF). This study also analyzes the factors that influence the concentration of Cd in the sediment and the interactions that occur in both phases. The supporting parameters are used DO, pH, redox potential, type of sediment, and total organic content. The Cd concentration in the surface sediments was analyzed at 12 sampling points using ICP-EOS. The research period conducted from 2015-2018 represents the rainy and dry season. <br /> <br /> <br /> The status of water quality based on the STORET Index the category of heavy pollutants. The STORET value in the rainy season is greater than the dry season. The water quality parameters that do not comply the quality standards based on PP 82 of 2001 class IV are BOD, COD, DO, H2S, and Nitrite. The concentration of Cd that contained in the reservoir water from 2008-2017 showed a value range of 0.00-0.139 mg/L, which still fulfilled the standard 0.01 mg/L. In the rainy season, the trend of Cd concentration in the water tends to decrease, on the contrary in the dry season it is increased. <br /> <br /> <br /> The total concentration of Cd in the reservoir sediments in the wet and dry seasons is higher when compared with the standard used, such as ANZECC.,1997 amounted 1.5 mg/kg. The concentration of Cd in the sediments in rainy season is 11.43-16.68 mg/kg with an average of 14.8±1.48 mg/kg. In the dry season, the Cd concentration is between 8.10-15.7 mg/kg with an average of 11.12±2.16 mg/kg. In the dry season, the average concentration of Cd from the largest to the smallest is station 1A> 1B> 4> 2> 9> 3> 8> 6> 5> 7> 10A> 10B while in the rainy season is 4> 1A> 1B> 2> 7 > 5> 9> 3> 6> 10A> 8> 10B. The sediment quality is using the Igeo method includes highly to extremely polluted categories in the rainy and dry season at all sampling points. Based on the CF method includes the category of very high contamination in the rainy and dry seasons at all sampling points. MPI method shows that the sediment has been contaminated with Cd, the MPI value of the wet season reaches 43.38 higher than in the dry season that amounted 32.17. The PERI method categorizes the sediment quality including serious ecological risk in the rainy and dry season, it means that the Cd pollution has a serious impact on the reservoir ecosystem. This study uses four sediment quality indexes with the Cb value is based on the results of research conducted in the reservoir catchment area with a value of 0.34±0.10 mg/kg. The pollution load of the Cd that entering the dry season reservoir is 7.654 kg/day. The highest Cd pollution load comes from the Citarum River. <br /> <br /> <br /> The result of speciation analysis of Cd in the sediment shows that the sequence of the largest to the smallest fraction in the rainy and dry season is F4>F2>F3>F1. This shows that the Cd that mostly in the F4 fraction comes from natural activities such as rock decay containing the Cd. The high concentration of F4 fraction shows that most of the Cd content in the sediment is a crystalline mineral and the residual fraction that collected in the bottom layer of the mud. Comparison of bioavailability (F1) concentrations in the rainy season is smaller than in the dry season. The highest F1 concentration occurred at point 1A such as in Nanjung which indicates that Cd pollution has occurred from human activity. Based on the RAC value, the reservoir sediments is including the low risk categories in the rainy and dry season. The dry season of RAC value is higher when compared to the rainy season, indicating that in the dry season Cd is more bioavailable and easily to enter the food chain in the Saguling Reservoir. Based on the GCF method indicate that the metal source comes from natural activities because the F4 fraction occupies the highest position. <br /> <br /> <br /> The results of laboratory experiments to investigate the deposition process and the resuspension of Cd in the sediment concluded that: (1) the Cd partition coefficient in the sediment is between 506.92-2.083.00 L/kg; (2) the mass transfer coefficient of Cd from the water column to the sediment (2k'A3) is 83.33-250.00 cm/hour. The coefficient of mass transfer of Cd from the sediment to the water column (3k'A2) is between 0.002-0.0023 cm/hour. Total mass transfer coefficient (3K'A2) from the deposition process and the sediment resuspension is between 0.000020-0.000023 cm/hour; (3) the time needed to restore the reservoir water quality due to the Cd pollution naturally during 318-327 years. The higher of the resuspension process that occurs the more time needed to recover; (4) the Cd concentration after the recovery period between 0.010-0.013 mg/L. Considering that the recovery time required is too long, it is necessary to control the Cd pollution in the Saguling Reservoir. The four main factors controlling water pollution, such as environmental rehabilitation, law enforcement, institutions, and community participation are strongly needed to reduce the Cd pollution load into the Saguling Reservoir. <br />