M. Aktaruzzaman
Department of Environmental Sciences, Jangirnagar University, Dhaka - 1342, Bangladesh
A.N.M. Fakhruddin
Department of Environmental Sciences, Jangirnagar University, Dhaka - 1342, Bangladesh
M.A.Z. Chowdhury
Agrochemial & Environmental research Division, IFRB, AERE Savar, Dhaka - 1349, Bangladesh
Z. Fardous
Agrochemial & Environmental research Division, IFRB, AERE Savar, Dhaka - 1349, Bangladesh
M.K. Alam
Agrochemial & Environmental research Division, IFRB, AERE Savar, Dhaka - 1349, Bangladesh
Heavy metals, Leafy vegetables, AAS, Transfer factoe, Ecological risk factor
Department of Environmental Sciences, Jangirnagar University, Dhaka
Risk Management in Agriculture
Reference standard for heavy metals: Reference standard heavy metals Cadmium, Copper, lead, Chromium, Manganese, Iron and Zinc were obtained from Kanto Chemical Co. Inc. Hydrochloric acid and Nitric acid were obtained from Merck.
Description of the study area: The area selected for the study was along the Dhaka Aricha Road and near the Savar area about 17 km north from Dhaka centre and runs northward. The site was selected for this study because it links capital Dhaka city Dhaka and it has a comparatively high traffic density. The study site is also exposed to different degrees of industrial pollution especially textile dying industries.
Collection of soil sample: Soil samples (1 kg each) were collected from along the Dhaka Aricha Road. Polyethylene bags were used for collecting the soil sample. The samples were transferred to the laboratory as early as possible. The samples were properly labeled and preserve at -20°C to preclude the risk of hydrolysis and oxidation.
Collection of vegetables sample: Fresh leafy vegetables (Red Spinach) samples were randomly collected from the sides along the Dhaka Aricha road. Vegetables samples were stored in polyethylene bags in the field, the samples were transferred to the laboratory as early as possible. Samples were directly oven dried at temperature of 75°C for 24 h and then finally crushed and sieved at room temperature conditions. The sieved samples were stored in airtight sealed plastic bottles until required for analysis.
Soil sample preparation and digestion procedure: Soil samples were oven dried at 95°C for 48 h and ground into fine powder using pestle and mortar. Further 15 g of fine powder sediment sample was taken in a conical flask to which 15 mL of 1M HNO3 were added. Then 30 mL of distilled water was added to the mixture and the solution kept 24 h. After 24 h distilled water was added to the solution and making the solution 150 g by weight and the sample was centrifuged and filtered by Whatman No. 41 filter paper. Filtrates were then analyzed by AAS.
Vegetable sample preparation and digestion procedure: Samples were digested with Nitric acid for heavy metal determination. Once collected, samples were first washed with normal tap water. All washed samples were carefully air dried, cut into small pieces and drying in the oven at 60°C for 24 h until samples became fully dry. This was followed by grinding and homogenization of the dried samples into fine powder using an electric grinder. The powdered samples are then stored in closed containers in absence of humidity. Vegetables samples (1.00±0.001 g) were placed into crucible, to which 10 mL of acid 65% high purity HNO3 was added. The mixture was then digested at 60°C till the solution became semi dried. Again 10 mL of con HNO3 and 4 mL of H2O2 was added and again kept on hot plate for 1 h. After getting semi dried than cooled and filtered with the help of what men filter paper. Volume of the residues was made up to 50 mL with 2 M HNO3· Finally, the solution was analyzed.
Determination of heavy metal concentrations of soil and vegetables samples: Atomic Absorption Spectroscopy (AAS) (Model: AA-6401F, Shimadzu, Made in Australia), was used for the determination of heavy metals. To provide element specific wavelengths, a light beam from a lamp whose cathode is made of the element being determined is passed through the flame.
Pakistan Journal of Biological Sciences, 16: 332-338; ISSN 1028-8880
Journal