Zohre Moeini; Abooalfazl Azhdarpoor; Saeed Yousefinejad; Shima Bahrami
Volume 6, Issue 1 , January 2018, , Pages 8-15
Abstract
Background: Atrazine is one of the most widely used chlorinated herbicides with properties, such as sustainability in soil and ability to penetrate into water sources. This study aimed to investigate the photo-degradation of atrazine using ultraviolet ray and to identify its by-products. Methods: The ...
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Background: Atrazine is one of the most widely used chlorinated herbicides with properties, such as sustainability in soil and ability to penetrate into water sources. This study aimed to investigate the photo-degradation of atrazine using ultraviolet ray and to identify its by-products. Methods: The efficiency of atrazine removal under UV irradiation with a power of 6-125 watts was investigated and some effective parameters, such as initial concentration (10-100 mg/l) and pH (3-5), were studied during the radiation period (5-90 minutes). In all experiments, the volume of the solution used in 250-ml Erlenmeyer flask was 100 ml. After all, the final and by-products produced during this process were identified by mass gas chromatography. Results: The results showed that the removal efficiency did not change significantly by increasing pH. With increasing lamp power from 6 to 125 watts at one hour, the degradation efficiency increased by 24.5%, 23.5%, and 29.7% at concentrations of 10, 30, and 50 mg/l, respectively. Also, by increasing time from 5 to 15 minutes under the 125-watt radiation, the removal efficiency increased from 45.6 to 96.8%. Examining the results of mass gas chromatography revealed that atrazine photolysis process progressed towards the mineralization of atrazine. Accordingly, organic chlorine transformed to chlorine ion and organic nitrogen involved in ammonium and nitrate molecules. Conclusion: Overall, the results indicated that photolysis at the wavelength of 254 nm could be used along with other purification methods to completely remove atrazine and simultaneously disinfect contaminated water sources.
Marziyeh Ansari Shiri; mansooreh dehghani; Mohammad Reza Samaei
Volume 4, Issue 3 , July 2016, , Pages 121-128
Abstract
Background: Atrazine is a widely used herbicide. The increasing salinity of many water resources has had a negative effect on atrazine biodegradation. The aim of this study was to isolate atrazine degrading bacteria in semi-salinity media. Methods: Nine selected bacterial species were cultivated on ...
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Background: Atrazine is a widely used herbicide. The increasing salinity of many water resources has had a negative effect on atrazine biodegradation. The aim of this study was to isolate atrazine degrading bacteria in semi-salinity media. Methods: Nine selected bacterial species were cultivated on the mineral salt broth culture medium containing atrazine (50, 100, 500 mg/L), NaCl concentration (10 g/L), and 2% (wt/vol) agar. The bacteria with higher growths in the atrazine medium (500 mg/L) were selected. Then, those with higher growths were transferred to the medium with atrazine concentration of 1000 mg/L. The atrazine biodegradation rates by Ochrobactrum oryzae and consortium bacteria (all of the nine bacteria species) were compared by cultivating separately on the mineral salt broth containing atrazine concentration of 30 mg/l, and NaCl concentration of 10 g/L in the incubation time of 10 day and HPLC analysis. Results: The results indicated that Ochrobactrum oryzae had the highest growth compared to the other investigated bacteria (Acinetobacter radioresistens, Paenibacillus lautus, and Bacillus sp) in the mineral salt broth culture medium containing atrazine concentrations (1000 mg/L), NaCl (10 g/L), and 2% (wt/vol) agar. In the Ochrobactrum oryzae and bacterial consortium comparison, atrazine biodegradation rate in the culture medium containing NaCl, by Ochrobactrum oryzae, was higher than bacterial consortium and atrazine biodegradation rate in the culture medium with no NaCl addition, by Ochrobactrum oryzae, was lower than bacterial consortium. Conclusion: Based on the results, Ochrobactrum oryzae was significantly capable of atrazine biodegradation in the semisalinity aqueous environment.
narges shamsedini; Mohammad Ali Baghapour; Mansooreh Dehghani; Simin Nasseri
Volume 3, Issue 3 , July 2015, , Pages 94-100
Abstract
Background: Atrazine is one of the most widely used triazine herbicides which has been used for controlling broadleaf and grassy weeds for many years. Its widespread use in water has caused environmental concern because of frequent detection of atrazine in aquatic systems where this herbicide has been ...
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Background: Atrazine is one of the most widely used triazine herbicides which has been used for controlling broadleaf and grassy weeds for many years. Its widespread use in water has caused environmental concern because of frequent detection of atrazine in aquatic systems where this herbicide has been spilled. Therefore, the purpose of this study was to determine the herbicide removal efficiency at the optimal conditions. Methods: The effect of different parameters including pH at three different levels (3-11), the initial concentration of atrazine at three different levels (0.1-10 mg/L), and reaction time at five different levels (0-120 min) on the removal of atrazine in the aqueous phase using ultraviolet radiation (1020 μw/cm2) was investigated. Finally, the data were analyzed using SPSS software (version 16). Results: The results demonstrated that atrazine removal rate increased by increasing pH, initial atrazine concentration, and reaction time. The maximum rate of atrazine removal (99.2%) at optimal condition occurred in pH=11, atrazine concentration=10 mg/L at 30 min. Conclusion: According to the findings, it can be concluded that the UV-A process is an effective and commodious method for reducing atrazine in polluted water resources.