Biodegradation of Atrazine in Fertile Nile Delta Clay Soil under an Intensive Multicrop Rotation Farming System (original) (raw)
Related papers
Long-term maintenance of rapid atrazine degradation in soils inoculated with atrazine degraders
Water, Air, & Soil …, 2003
Two different microbial communities able to degrade atrazine (atz) were inoculated in four different soils. The most critical factor affecting the success of inoculation was the soil pH and its organic matter (OM) content. In two alkaline soils (pH > 7), some inoculations led immediately to a strong increase of the biodegradation rate. In a third slightly acidic soil (pH = 6.1), only one inoculum could enhance atz degradation. In a soil amended with organic matter and straw (pH = 5.7, OM = 16.5%), inoculation had only little effect on atz dissipation on the short as well as on the longterm. Nine months after the microflora inoculations, atz was added again and rapid biodegradation in all alkaline inoculated soils was recorded, indicating the long-term efficiency of inoculation. In these soils, the number of atz degraders was estimated at between 6.5 × 10 3 and 1.5 × 10 6 (g of soil) −1 , using the most probable number (MPN) method. Furthermore, the presence of the atz degraders was confirmed by the detection of the gene atzA in these soils. Denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rDNA genes indicated that the inoculated bacterial communities had little effect on the patterns of the indigenous soil microflora.
BIODEGRADATION AND MOBILITY OF- ATRAZINE IN SOIL
Biodcgradation and mobility of atrazine [2-chloro-4-(ethyIammo)-6-(isopropyIamino)-s-triazine] in two soils were studied under laboratory conditions. The half-life of disappearance was 17 days and 11.89 days in aerobic sandy loam and clay loam soil, respectively. Four weeks after application, atrazine was completely disappeared from clay loam soil, while it decreased to 0.23% in sandy loam soil. Atrazine degraded very slowly under anaerobic conditions and hardly in sterilized soils. Atrazine was determined to be less mobile in both sandy loam and clay loam soils. The quantifiable atrazine percentages accounted to be less than 10% at depth 30-45cm after 14days from application in the two tested soils. After 30 days and at the same layer, atrazine percentage was 2.3% in sandy loam soil, while the compound was completely dissipated from clay loam soil. No quantifiable determinations of atrazine were found below the depth of 30-45 cm in both tested soils. The results of HPLC analysis demonstrated that trace amounts of atrazine products were detected under aerobic conditions.
Biodegradation, 1996
The purpose of the present study was to assess atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) mineralization by indigenous microbial communities and to investigate constraints associated with atrazine biodegradation in environmental samples collected from surface soil and subsurface zones at an agricultural site in Ohio. Atrazine mineralization in soil and sediment samples was monitored as ~4CO2 evolution in biometers which were amended with 14C-labeled atrazine. Variables of interest were the position of the label ([U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine), incubation temperature (25°C and 10°C), inoculation with a previously characterized atrazine-mineralizing bacterial isolate (M91-3), and the effect of sterilization prior to inoculation. In uninoculated biometers, mineralization rate constants declined with increasing sample depth. First-order mineralization rate constants were somewhat lower for [2-14C-ethyl]-atrazine when compared to those of [u-t4C-ring]-atrazine. Moreover, the total amount of 14CO2 released was less with [2-14C-ethyl]-atrazine. Mineralization at 10°C was slow and linear. In inoculated biometers, less 14CO2 was released in [2-14C-ethyl]-atrazine experiments as compared with [U-lac-ring]-atrazine probably as a result of assimilatory incorporation of 14C into biomass. The mineralization rate constants (k) and overall extents of mineralization (Pma~) were higher in biometers that were not sterilized prior to inoculation, suggesting that the native microbial populations in the sediments were contributing to the overall release of 14CO2 from [U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine. A positive correlation between k and aqueous phase atrazine concentrations (Ceq) in the biometers was observed at 25°C, suggesting that sorptio n of atrazine influenced mineralization rates. The sorption effect on atrazine mineralization was greatly diminished at 10°C. It was concluded that sorption can limit biodegradation rates of weakly-sorbing solutes at high solid-tosolution ratios and at ambient surface temperatures if an active degrading population is present. Under vadose zone and subsurface aquifer conditions, however, low temperatures and the lack of degrading organisms are likely to be primary factors limiting the biodegradation of atrazine.
Journal of applied …, 2009
Atrazine (6-chloro-N-ethyl-N-(1-methylethyl)-1,3,5-triazine-2,4-diamine), one of the most widely used herbicides, has been applied to control broad-leaf weeds for corn, sorghum, sugarcane and other crops. The widespread use of this herbicide has led to its contamination in different environmental media (Wauchope 1978; Jayachandran et al. 1994; Koskinen and Clay 1997). Atrazine concentrations above the allowable contaminant levels for drinking water of 0AE1 and 3 lg l)1 in Europe and the United States, respectively, have been frequently detected (Rousseaux et al. 2003). Biodegradation is one of the key attenuation processes of atrazine in the environment. Previous research on atrazine biodegradation focused on pure atrazine-degrading cultures (
Atrazine biodegradation by stimulating the activity of soil bacterial population in maize field
International Journal of Biosciences, 2015
Nowadays, environmental pollution is a worldwide issue. Uncontrolled application of chemical inputs to agricultural fields has contaminated soil and water resources; endangering the health of all life forms on earth. One of the most important, cost-effective and safest methods of removing herbicide residues from soil is bioremediation which means using microorganisms such as plant growth promoting rhizobacteria to biodegrade chemicals residue. Application of bacteria to increase the decomposition rate of chemical herbicides in soil is a reliable method; which is the objective of this experiment. So, an experiment was conducted in factorial in the form of a randomized complete block design with three replications in a maize field in Shahriar, Iran. Treatments included bacterial species in four levels (control, Pseudomonas fluorescence, P. putida and combination of P. fluorescence + P. putida) and atrazine concentration in four levels (0, 1, 2 and 3 kg/ha). HPLC was used to analyze sa...
Microbial Degradation and Residue Analysis of Atrazine in Open Field and Indoor Cultures
2017
1 Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah. P.O. Box 80200 Jeddah 21589, Kingdom of Saudi Arabia 2 Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt *Corresponding Author’s E-mail: ebtesamelbestawy@yahoo.com Phone: +203-4295007 Fax:+203-4285793 The present study aimed to investigate Atrazine residues and biodegradation by naturally occurring bacteria in open field and indoor cultures of corn and cucumber amended with Atrazine. Three soil types were employed to evaluate the effect of soil characteristics including the indigenous degraders on the fate of Atrazine different ecosystems. In the field experiment, corn grew well to its full cycle (120 days) in the presence of the Atrazine at its recommended dose (RD). Cucumber plant grew only to its full cycle in the presence of 0.5 XRD of the herbicide in soil E while it did not g...
In-Situ Biostimulatory Effect of Selected Organic Wastes on Bacterial Atrazine Biodegradation
Advances in Microbiology, 2012
The biostimulatory effect of selected organic wastes on bacterial biodegradation of atrazine (2-chloro-4-ethylamino-6isopropylamino-1,3,5-triazine) in three agricultural soils in Bauchi state, Nigeria, was carried out. The soil physicochemical characteristics were investigated to further understand the environmental conditions of the sampling sites. Enrichment technique was used to isolate the atrazine-degrading strains. Mineralization studies were carried out to determine atrazine biodegradation potentials of strains. Polymerase Chain Reaction (PCR) amplification of total nucleic acid of strains revealed several bacterial species based on nucleotide sequence analyses. Biostimulatory effect of selected organic wastes carried out showed minimal to average extent of biodegradation. The highest mean values, in CFU/mL, increase in biomass was recorded in Pseudomonas sp for both Cow dung 16.76 (42.03%) and Chicken droppings 12.32 (38.46%). However, biostimulatory effect using consortia provided more promising results, with 41.51% and 42.08% in Cow dung and Chicken droppings, biomass increase, respectively, in studies conducted. This proves that competition, survival of inoculums, bioavailability of organic amendments and nature of chemical are important factors affecting bioremediation.
2011
The s-triazine herbicide atrazine was rapidly mineralized (i.e., about 60% of 14 C-ring-labelled atrazine released as 14 CO 2 within 21 days) by an agricultural soil from the Nile Delta (Egypt) that had been cropped with corn and periodically treated with this herbicide. Seven strains able to degrade atrazine were isolated by enrichment cultures of this soil. DNA fingerprint and phylogenetic studies based on 16S rRNA analysis showed that the seven strains were identical and belonged to the phylogeny of the genus Arthrobacter (99% similarity with Arthrobacter sp. AD38, EU710554). One strain, designated Arthrobacter sp. strain TES6, degraded atrazine and mineralized the 14 C-chain-labelled atrazine. However, it was unable to mineralize the 14 C-ring-labelled atrazine. Atrazine biodegradation ended in a metabolite that co-eluted with cyanuric acid in HPLC. This was consistent with its atrazine-degrading genetic potential, shown to be dependent on the trzN, atzB, and atzC gene combination. Southern blot analysis revealed that the three genes were located on a large plasmid of about 175 kb and clustered on a 22-kb SmaI fragment. These results reveal for the first time the adaptation of a North African agricultural soil to atrazine mineralization and raise interesting questions about the pandemic dispersion of the trzN, atzBC genes among atrazine-degrading bacteria worldwide.
International Biodeterioration & Biodegradation, 2011
The s-triazine herbicide atrazine was rapidly mineralized (i.e., about 60% of 14 C-ring-labelled atrazine released as 14 CO 2 within 21 days) by an agricultural soil from the Nile Delta (Egypt) that had been cropped with corn and periodically treated with this herbicide. Seven strains able to degrade atrazine were isolated by enrichment cultures of this soil. DNA fingerprint and phylogenetic studies based on 16S rRNA analysis showed that the seven strains were identical and belonged to the phylogeny of the genus Arthrobacter (99% similarity with Arthrobacter sp. AD38, EU710554). One strain, designated Arthrobacter sp. strain TES6, degraded atrazine and mineralized the 14 C-chain-labelled atrazine. However, it was unable to mineralize the 14 C-ring-labelled atrazine. Atrazine biodegradation ended in a metabolite that co-eluted with cyanuric acid in HPLC. This was consistent with its atrazine-degrading genetic potential, shown to be dependent on the trzN, atzB, and atzC gene combination. Southern blot analysis revealed that the three genes were located on a large plasmid of about 175 kb and clustered on a 22-kb SmaI fragment. These results reveal for the first time the adaptation of a North African agricultural soil to atrazine mineralization and raise interesting questions about the pandemic dispersion of the trzN, atzBC genes among atrazine-degrading bacteria worldwide.
Atrazine degradation in boreal nonagricultural subsoil and tropical agricultural soil
Journal of Soils and Sediments, 2014
Purpose The purpose of this study was to determine the natural atrazine degradation activity and the genetic potential in a soil profile spanning down to the groundwater zone, collected in Finland at a site where past use of atrazine has contaminated the groundwater, and in Indian agricultural topsoils having different histories of atrazine use. Materials and methods Atrazine degradation potential was assessed by quantifying the atrazine degradation genes atzA, trzN, and atzB by quantitative PCR reaction. Atrazine mineralization was studied by radiorespirometry in order to find out if these genes were expressed. Results and discussion Indian soils contained a large number up to 10 4 -10 5 copies (g −1 dry weight (dw) soil) of atrazine degradation genes after the first treatment with atrazine. These genes were also expressed, as up to 55 % of atrazine mineralized. Some unspecific binding of primers required thorough investigation and confirmation by sequencing of the qPCR products in the agricultural soil samples. The degradation capability of the nonagricultural boreal soil profile was much lower: atrazine degradation genes were present at detection limit (10 2 copies g −1 soil), but mineralization studies indicated that these genes were not transcribed, since no or very little atrazine mineralization was observed. Conclusions Our results indicate that when atrazine was applied in agricultural practice, the soil atrazine degradation capacity was high. The organisms responsible for the degradation were effectively degrading atrazine already 3 months after the first treatment with atrazine. However, in boreal soil, decades after atrazine use had been discontinued, residual atrazine was not degraded even though a small number of degradation genes could still be detected in soil. There is a need for more specific primers for qPCR in tropical soils.