M. S. Hossain
Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh.
M. Alamgir Zaman Chowdhury
Agrochemical and Environmental Research Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka 1349, Bangladesh.
Md. Kamruzzaman Pramanik
Microbiology and Industrial Irradiation Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka 1349, Bangladesh.
M. A. Rahman
Agrochemical and Environmental Research Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka 1349, Bangladesh.
A. N. M. Fakhruddin
Department of Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh.
M. Khorshed Alam
Agrochemical and Environmental Research Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka 1349, Bangladesh.
Pesticides, Agricultural water, HPLC, Organophosphorus insecticide, Chlorpyrifos, Biodegradation
Microbiology and Industrial Irradiation Division, Institute of Food and Radiation Biology (IFRB), Atomic energy Research Establishment, Savar and Jahangirnagar University Campus, Dhaka.
Crop-Soil-Water Management
Reference grade standards for methoxychlor (99.5 %), DDT (99.0 %), chlorpyrifos (99.5 %), diazinon (99.5 %), ethion (99.0 %), fenthion (98.5 %), fenitrothion (99.0 %), malathion (99.5 %), parathion (99.0 %), carbaryl (99.0 %), carbofuran (99.5 %) and cypermethr in (99.0 %) were purchased from GmbH (D -86199 Augsburg , Germany). The organic solvents including n -hexane, diethyl ether and dichlorom ethane were of analytical grade while acetonitrile was of HPLC grade. Anhydrous Sodium Sulfate, Florisil and formulated chlorpyrifos were also used. Water samples from lakes adjacent to agricultural fields of Savar, Bangladesh were collected from February to March, 2012. The samples were kept in clean amber glass bottles, put into ice boxes and immediately transferred to the laboratory at the Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka. Sample collection was performed. The samples were properly labeled and kept at - 20oC before analysis according to Uddin et al. (2007). Five hundred milliliter of water sam ple and 100 ml solvent (2 % diethyl ether in double-distilled n -hexane) were taken into a 1,000-ml capacity separating funnel (DURAN , Germ any) and was shaken by mixing well for about 10 min and then kept standing for 10–15 mi n for settling down. The organic solvent was collected in a conical flask. The evaporated sample was dissolved in acetonitrile, and a 1 -ml volume was used for the HPLC analysis. After the sample cleanup, aliquots of the final volume were quantified with a HPLC system (SHIMADZU LC-10 Avp- Series Automated with LC Solution Software LabSolutions (LC solution Release 1.11SP 1) that was equipped with a SPD-M 10 Avp outfitted with a photo-diode arr ay (PD A) detector. A C18 Reverse Phase Alltech analytical column (5 lm, 250 9 4.6 mm) was used and maintained at 30oC in a column oven. The mobile phase, which was a combination of 70% acetonitrile and 30 % water, was filtered using a cellulose filter (0.45 l m) prior to use and was allowed to run at 1.2 ml/m in. Prior to the HPLC analysis, the samples were passed through 0.45lm nylon (Alltech Assoc) syringe filters and were manually injected (20 ll) into the HPLC system each time. The identification of the suspected pesticide was performed by comparing peak retention times in samples to those of peaks in the p ure analytical standard. Quantification was performed using the method. The mean percent age recoveries of all tested pesticides were more than 85 % which was satisfactory. These values were quite satisfactory and meet the requirements of the (European Commission 2000), indicating that a method can be considered accurate and precise when the accuracy of data is between 70 and 110 %. The Limit of detect ion (LOD) for the pesticides was 0.1 lg/lThree bacterial isolates viz., Pseudomonas peli BG1, Burkholderia caryophylli BG4 and Brevundimonas diminuta PD6 were collected from Microbiology and Industrial Irradiation Division, Institute of Food and Radiation Biology (IFRB), Atomic energy Research Establishment, Savar, Dhaka. The organisms were isolated from botanical garden of Jahangirnagar University campus in October 2011.The mineral salt medium used in biodegradation studies, adapted from Cyc on et al. ( 2009), contained (g/l) (NH4)2SO 4 , 2.0; KH2PO4, 1.5; Na2HPO 4, 1.5; MgSO4. 7H2O, 0.2; CaCl2, 2H2O, 0.01; FeSO4. 7H2O, 0.001. The pH of the medium was adjusted to 7.0 ± 0.1 with 2 M NaOH . Growth experiments with chlorpyrifos as a sole carbon source were performed in 250-ml conical flasks contain ing 95 ml of ste rile miner al salt med ium (MSM). Samples of liquid medium were periodically removed aseptically for measuring of bacterial growth (OD600 nm ) and pH using UV–visible spectrophotometer (U V-1601, SHIMA DZU) and pH meter (3510 pH meter, JENWAY, Bibby Scientific Ltd., UK), respectively. The final supernatant was taken into eppendorf and kept in refrigerator prior to their analysis using HPLC. The study period for the biodegradation of chlorpyrifos was up to 12 days when 20 mg/ chlorpyrifos was supplied as a sole source of carbon and up to 16 days whe n 50 mg/l chlorpyrifos was supplied as a sole source of carbon.
Appl Water Sci (2015) 5:171–179
Journal