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Assessing Metallic Toxicity of Wastewater for Irrigation in Some Industrial Areas of Bangladesh
( Mokhlesur Rahman ),( Abu Sayem Jiku ),( Jang Eok Kim ) 한국환경농학회 2011 한국환경농학회지 Vol.30 No.2
BACKGROUND: Wastewaters were collected from 25 sites of two industrial areas of Mymensingh and Gazipur in Bangladesh to assess metallic toxicity of wastewater for irrigation usage. METHODS AND RESULTS: The analyzed wastewaters were slightly alkaline to alkaline in nature and were problematic for irrigation except 3 samples. As per TDS values, 9 samples were rated as fresh water and the rest 16 were classified as brackish water. EC and SAR reflected that all samples were medium salinity (C2), high salinity (C3), very high salinity (C4) and low alkalinity (S1) hazard classes expressed as C2S1, C3S1 and C4S1. Wastewaters of different industries were graded as excellent, good, permissible and doubtful for irrigation purpose as per SSP. According to hardness (HT), wastewater were under moderately hard, hard and very hard classes. Cd, Cr and Cu ions were treated as toxicant for irrigating soils and crops. Zn was problematic for long-term irrigation. The concentrations of Pb, Fe and Na were far below the toxic levels. Synergistic relationships were observed between pH-EC, pH-TDS, EC-TDS, SAR-SSP and SSP-hardness. CONCLUSION(s): If wastewater is applied for irrigation due to the fresh water shortage, it can contaminate soil due to some toxic metal ions.
Removal Efficiency of the Herbicide Oxadiazon in Treatment Processes for Drinking Water
Mokhlesur, Rahman,Kim, Tae-Hwa,Kwon, Gi-Seok,Yang, Jae-E.,Park, Man,Kim, Jang-Eok The Korean Society for Applied Biological Chemistr 2009 Applied Biological Chemistry (Appl Biol Chem) Vol.52 No.3
A comparative study was performed to evaluate the removal efficiency of herbicide, oxadiazon as an organic contaminant in treatment processes for drinking water. In this investigation, three major treatment processes such as chlorination, ozonation and activated carbon treatment were applied separately to water system. The level of oxadiazon gradually decreased to 28%, when chloride as a disinfectant was applied to the water supply. Activated carbon treatments showed that this herbicide was removed efficiently from the aqueous solution. The results indicated that the performance of powdered activated carbon was more effective than granular activated carbon in terms of adsorption. The adsorption isotherms exhibited an excellent agreement with the experimental data and they were also well represented by the Langmuir and Freundlich equations, indicating the higher adsorption capacity for activated carbons. During ozone treatment, 50% of oxadiazon was removed but this removal was enhanced by the presence of hydrogen peroxide. The association of ozonation with chloride and activated carbon treatments was considered to be the best-tested treatment for drinking water production. Therefore, if oxadiazon enters into the water ecosystem as an organic contaminant, it could be removed effectively by the drinking water treatment processes.
( Mokhlesur Rahman ),( Abu Sayem Jiku ),( Abdul Alim ),( Jang Eok Kim ) 한국응용생명화학회 2014 Journal of Applied Biological Chemistry (J. Appl. Vol.57 No.2
An attempt was made to assess metal ionic toxicity levels of different fishes in the polluted rivers viz., Buriganga and Turag. Fish samples collected from two polluted rivers were analyzed for the levels of metals such as Cd, Cr, Cu, Mn, Pb, and Zn in order to elucidate the status of these contaminants in fish meant for human consumption. The detected concentrations of Cr, Cu, Mn, and Zn ions in fish species collected from the polluted rivers were below the toxic levels and did not appear to pose a threat. Among the analyzed metals, Cd and Pb ions were detected above the permissible levels in liver and muscle tissues of stinging catfish (Heteropneustesfossilis), spotted snakehead (Channapunctata) and wallago (Wallagoattu) collected from the polluted rivers causing toxicity for human consumption. Stinging catfish (Heteropneustesfossilis) was the species found to highly bioaccumulate these metals. Fish species bioconcentrated appreciable amounts of Cd and Pb as toxic metals in the liver as compared to the muscle. Levels of these toxic metals varied depending on different tissues in fish species.
Remediation of Water Contaminated with Herbicide Oxadiazon Using Fenton Reagent
( Mokhlesur Rahman ),( Jang Eok Kim ) 한국응용생명화학회 2010 Applied Biological Chemistry (Appl Biol Chem) Vol.53 No.4
The remediation of water contaminated with herbicide oxadiazon was investigated by applying modified Fenton reagent (Fe3+/H2O2) at unadjusted pH. Experimental conditions in various reactions allowed for the disappearance of oxadiazon. When using Fenton reagent, the maximum degradation rate was obtained under exposure to UV irradiation as compared to dark condition in which the concentrations of ferric ion and hydrogen peroxide were 3 and 100 mM, respectively. After 5 h of photocatalytic treatment with Fenton reagent, 98.4% of the oxadiazon was degraded. The high degradation rate of this herbicide was achieved by hydroxyl radicals (OH`), which were generated by the photocatalytic treatment. UV irradiation accelerated the degradation of oxadiazon in the water system in the presence of Fenton reagent. In addition, the disappearance of oxadiazon was enhanced due to the increased concentrations of ferric ion and/or hydrogen peroxide. For the photo-Fenton reaction, one metabolite (m/z 310) was able to be identified using the GC-MS technique due to dechlorination of oxadiazon. Conclusively, a remediation strategy using Fenton reagent could be applied to degrade oxadiazon from contaminated water.