Mona Mansouri; Aptin Rahnavard; Masood Ghane
Abstract
Background and purpose: Diazinon is an organophosphorus insecticide that is widely used in paddy fields and gardens. The entry of resistant pollutants into drinking water sources, soil, and agricultural products can be harmful to human health and the environment. This study aimed to identify and isolate ...
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Background and purpose: Diazinon is an organophosphorus insecticide that is widely used in paddy fields and gardens. The entry of resistant pollutants into drinking water sources, soil, and agricultural products can be harmful to human health and the environment. This study aimed to identify and isolate diazinon-degrading bacteria and measure the amount of poison decomposed by superior bacteria in liquid and soil environments.Materials and methods: Sampling was conducted from Tonekabon gardens. The strains were identified and sequenced using polymerase chain reaction based on 16S rRNA. The rate of diazinon degradation by the isolated bacteria was measured by gas chromatographyResults: Two strains of diazinon-degrading bacteria, Serratia and Enterobacter cloacae, were identified. Bacteria with diazinon concentrations of 10 and 20 ppm were cultured in broth and soil for 10 days, and the amount of poison decomposition was measured. The results indicated that Serratia bacteria in the broth medium, with initial concentrations of 10 and 20 ppm, consumed 64.3% and 78.4% of diazinon, respectively, while in the soil with the same concentration, it decomposed 90.2% and 98.25% of diazinon. Enterobacter cloacae bacteria consumed and decomposed diazinon in the broth and soil environments, with percentages of 23.1, 17.95, 31.19, and 88.05%, respectively. According to the results, Serratia has a higher decomposition ability compared to Enterobacter.Conclusion: The results of this research showed that some microorganisms in the soil have the ability to decompose diazinon. Utilizing these microorganisms and other biological methods to clean contaminated soils can be a suitable approach.
Arezoo Khalijian; Soheil Sobhanardakani; Mehrdad Cheraghi
Abstract
Background & Objective: Increasing population growth, and therefore, increasing requirements for development of the agricultural productions, lead to be overused the pesticides. So, their residues in environment, particularly surface and groundwater resources, create human health risks. Therefore ...
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Background & Objective: Increasing population growth, and therefore, increasing requirements for development of the agricultural productions, lead to be overused the pesticides. So, their residues in environment, particularly surface and groundwater resources, create human health risks. Therefore due to the serious risk to human health, this study was carried out for assessing the diazinon residues in groundwater samples of Hamedan-Bahar Plain in 2014. Material and Methods: Water samples were collected from 20 stations along the Hamedan-Bahar Plain in summer 2014. After preparation and processing the samples in the laboratory according to liquid phase extraction, diazinon residues in samples were determined using a spectrophotometric method in three replications. All statistical analyses were performed by SPSS 20 software using Kolmogrov-Smirnov, one-way ANOVA, One Sample T Test and Pearson's Correlation Coefficient. Results:The results showed that the mean concentration of diazinon residues in samples was 0.23±0.06 µg/mL-1, being upper than the Maximum Contaminant Levels (MCLs) provided by the WHO. Conclusion:Since based on WHO guideline the mean concentrations of diazinon residues in groundwater resources of Hamedan-Bahar Plain were upper than MCLs, therefore; exploitation of water for drinking has adverse effect on consumers' health. In this regards, concerning increased use of agricultural inputs especially pesticides, regular periodic monitoring of chemical pollutants content in groundwater resources of study area is recommended.