Microbial Degradation of Terbuthylazine in Surface Soil and Subsoil at Two Different Temperatures

Caracciolo, Anna Barra; Giuliano, G.; Corcia, Antonio Di; Crescenzi, Carlo; Silvestri, Cecilia

doi:10.1007/s00128-001-0195-7

Cited by 7 publications

(8 citation statements)

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“…In this context, the relatively high half-life values (95-105 days) found in this clay loam soil could be ascribed to its fine texture and in particular to its clay mineral montmorillonite fraction which has a great capacity to adsorb organic matter (Arnarson 2000), including triazine herbicides, decreasing their bioavailability for degradation (Bailey et al 1986). In fact in our previous microcosm studies, performed with terbuthylazine in the same laboratory conditions but on different soils (silty-loam and sandy-loam), we observed a t 1/2 of 22 days and 30 days, respectively (Barra Caracciolo et al 2001;2005a).…”

Section: Discussionmentioning

confidence: 62%

Effects of Wood Amendments on the Degradation of Terbuthylazine and on Soil Microbial Community Activity in a Clay Loam Soil

Grenni

Rodríguez‐Cruz

Herrero‐Hernández

et al. 2012

Water Air Soil Pollut

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The herbicide terbuthylazine is widely used within the EU; however its frequent detection in surface and groundwater, together with its intrinsic toxicological properties, may pose a risk both for human and environmental health. Organic amendments have recently been proposed as a possible herbicide sorbent in soil, in order to limit herbicide movement from soil to water. The environmental fate of terbuthylazine depends not only in its mobility, but also its persistence. The latter is directly dependent on microbial degradation. For this reason the effects of pine and oak residues on terbuthylazine soil microbial community functioning and on the potential of this community for terbuthylazine degradation were studied. For this purpose, degradation kinetics, soil dehydrogenase activity and the number of live bacteria were assessed in a clay-loam soil treated with terbuthylazine and either amended with pine or oak wood or unamended (sterilized and non-sterilized). At day 65, 85% of the herbicide applied still persisted in the sterile soil, 73% in the pine-amended one and 63% in the oak-amended and unamended ones. Pine residues increased the sorption of terbuthylazine to soil and hampered microbial degradation owing to its high terbuthylazine sorption capacity and a decrease in the bioavailability of the herbicide. On the contrary, in the presence of oak residues the herbicide sorption did not increase significantly. The overall results confirm the active role of the soil microbial community in terbuthylazine degradation in amended and unamended soils and in a liquid enrichment culture performed using an aliquot of the same soil as the inoculum. In this clay loam soil, in the absence of amendments, the herbicide was found to be quite persistent (t 1/2 > 95 days), while in the enrichment culture the same natural soil bacterial community was able to halve terbuthylazine in 24 days. The high terbuthylazine persistence in this soil was presumably ascribable to its texture and in particular to the mineralogy of the clay fraction.

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Section: Discussionmentioning

confidence: 62%

Effects of Wood Amendments on the Degradation of Terbuthylazine and on Soil Microbial Community Activity in a Clay Loam Soil

Grenni

Rodríguez‐Cruz

Herrero‐Hernández

et al. 2012

Water Air Soil Pollut

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“…The bacterial abundance (number of bacteria per gram of soil) was measured by the epifluorescence direct count method, using as a fluorescent dye DAPI (4′,6′‐diamino‐2‐phenylindole) (Barra Caracciolo et al, 1999, 2001), since it allows distinction of bacteria (that appear with a luminescent blue color) from nonliving bacterium sized particles (that show up as yellow).…”

Section: Methodsmentioning

confidence: 99%

Fate of Diuron and Linuron in a Field Lysimeter Experiment

et al. 2006

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The environmental fate of herbicides can be studied at different levels: in the lab with disturbed or undisturbed soil columns or in the field with suction cup lysimeters or soil enclosure lysimeters. A field lysimeter experiment with 10 soil enclosures was performed to evaluate the mass balance in different environmental compartments of the phenylurea herbicides diuron [3-(3,4-diclorophenyl)-1,1-dimethyl-urea] and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea]. After application on the agricultural soil, the herbicides were searched for in soil, pore water, and air samples. Soil and water samples were collected at different depths of the soil profile and analyzed to determine residual concentrations of both the parent compounds and of their main transformation products, to verify their persistence and their leaching capacity. Air volatilization was calculated using the theoretical profile shape method. The herbicides were detected only in the surface layer (0-10 cm) of soil. In this layer, diuron was reduced to 50% of its initial concentration at the end of the experiment, while linuron was still 70% present after 245 d. The main metabolites detected were DCPMU [3-(3,4-dichlorophenyl)-1-methylurea] and DCA (3,4-dichloroaniline). In soil pore water, diuron and linuron were detected at depths of 20 and 40 cm, although in very low concentrations. Therefore the leaching of these herbicides was quite low in this experiment. Moreover, volatilization losses were inconsequential. The calculated total mass balance showed a high persistence of linuron and diuron in the soil, a low mobility in soil pore water (less than 0.5% in leachate water), and a negligible volatilization effect. The application of the Pesticide Leaching Model (PELMO) showed similar low mobility of the chemicals in soil and water, but overestimated their volatilization and their degradation to the metabolite DCPMU. In conclusion, the use of soil enclosure lysimeters proved to be a good experimental design for studying mobility and transport processes of herbicides in field conditions.

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“…The microbial abundances (no./g soil) were measured using the epifluorescence direct count method reported in detail in previous works [13,27]. At each sampling, 1 g soil (three replicates) was sampled from each treated and untreated soils and fixed in a test tube containing a filter-sterilized solution (4% formaldehyde solution and 0.5% Tween 20).…”

Section: Microbial Analysismentioning

confidence: 99%

Effect of urea on degradation of terbuthylazine in soil

Caracciolo

Giuliano

Grenni

et al. 2005

Enviro Toxic and Chemistry

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Pesticide and nitrate contamination of soil and groundwater from agriculture is an environmental and public health concern worldwide. The herbicide terbuthylazine (CBET) has replaced atrazine in Italy and in many other countries because the use of the latter has been banned because of its adverse environmental impacts. Unlike atrazine, knowledge about the fate of CBET in soil is still not extensive, especially regarding its transformation products, but recent monitoring data show its occurrence and that of its main metabolite, desethyl-terbuthylazine (CBAT), in groundwater above the limit of 0.1 microg/L established by European Union Directive and Italian legislation. The objective of this work was to investigate if the presence of the fertilizer urea affects CBET degradation in the soil. Laboratory CBET degradation experiments in the presence/absence of urea were performed with microbiologically active soil and sterilized soil. Terbuthylazine degradation rates under the different experimental conditions were assessed, and the formation, degradation, and transformation of the metabolite CBAT were also studied. Terbuthylazine degradation was affected by the presence of urea, in terms both of a higher disappearance time of 50% of the initial concentration and of a lower amount of CBAT formed. These findings have practical implications for the real-life assessment of the environmental fate of triazine herbicides in agricultural areas since these herbicides are frequently applied to soils receiving ureic fertilizers.

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Microbial Degradation of Terbuthylazine in Surface Soil and Subsoil at Two Different Temperatures

Cited by 7 publications

References 0 publications

Effects of Wood Amendments on the Degradation of Terbuthylazine and on Soil Microbial Community Activity in a Clay Loam Soil

Effects of Wood Amendments on the Degradation of Terbuthylazine and on Soil Microbial Community Activity in a Clay Loam Soil

Fate of Diuron and Linuron in a Field Lysimeter Experiment

Effect of urea on degradation of terbuthylazine in soil

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