A Study on the Determination of Heavy Metals in Sediment of Fish Farms in Bangladesh

摘要

Heavy metals in mud surface sediments have been determined to assess environmental pollution of the selected fish farms in Mymensingh, Bangladesh. Surface sediment samples (0-15 cm) from 20 ponds of a fish farm were collected in February 2014 with a single core sampler and were analysed to measure the concentrations (mg/Kg DW) of Zinc (Zn), Lead (Pb), Cadmium (Cd), Nickel (Ni) and Chromium (Cr) by atomic absorption spectrometry using a VARIAN model AA2407 in Bangladesh Agricultural Research Institute’s laboratory. The measured concentration of heavy metals in the present study was in order of, Zn Cr Ni Pb Cd which are quite similar to the findings of other sediment of pond mud. The mean concentrations of Zn, Pb, Cd, Cr, Ni observed in the present study were 208, 14.845, 0.009, 63.054 and 58.665 mg/kg respectively. The ranges of the measured concentrations (mg/kg) in the total sediments were 11.5-18.5 for Pb, 0.007-0.011 for Cd, 53.5-77.3 for Cr, 50.8-66.4 for Ni and 100-250 for Zn. The concentrations of Zn and Ni in all sediment samples were above the US Environmental Protection Agency’s (USEPA) guideline for severely polluted sediment and the concentration of Cr falls under the moderately polluted range. The metal Pb and Cd concentrations are well below the regulated level as per USEPA. Therefore, the study results revealed that the pond mud sediment quality in Mymensingh region might be considered as highly and moderately polluted for Zn, Ni and Cr respectively.