Kinetics of Alachlor and Atrazine Biotransformation Under Various Electron Acceptor Conditions

Wilber, Gregory G.; Parkin, Gene F.

doi:10.1897/1552-8618(1995)14[237:koaaab]2.0.co;2

Cited by 5 publications

(6 citation statements)

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“…Likewise, apparent first-order rate coefficients have been observed for the processes of disinfection and detachment of biofilms (30)(31)(32) and the aerobic biological degradation of chlorinated aliphatic hydrocarbons using a completely mixed laboratory biofilm reactor (33). One exception to this trend, however, was the second-order kinetics observed for the biotransformation of the herbicides atrazine and alachlor under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions (34).…”

Section: Resultsmentioning

confidence: 97%

Rates of Sorption and Partitioning of Contaminants in River Biofilm

Headley

Gandrass

Kuballa

et al. 1998

Environ. Sci. Technol.

129

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Biofilms are believed to play a significant role in the fate and transport of contaminants in aquatic environments. However little is known about the rates of sorption (k) and partitioning (K d) of contaminants to biofilms. Studies of the latter were performed using mature biofilm cultivated in a roto-torque reactor. The reactor was flushed with river water containing a mixture of tetrabutyltin, p,p-DDT, diclofop-methyl, triallate, lindane, atrazine, parathion-methyl, and dimethoate in two experiments. The first experiment was conducted at a spiked level of 1 μg/L, and the second was conducted at 10 μg/L for each component. Apart from dimethoate, there was rapid depletion of all contaminants from the water phase within the first 5−10 min with sorption occurring by pseudo-first-order kinetics. In general, the mean values of k (10-4 min-1) increased with water solubility and were 8, 70, 110, 180, 230, 370, and 100 for p,p-DDT, diclofop-methyl, triallate, tetrabutyltin, lindane, atrazine, and parathion-methyl, respectively. The values of log K d increased linearly with log K ow and decreased linearly with the log of the aqueous solubilities. In general, K ow values were significantly greater than the corresponding values of K d, indicating that partitioning of contaminants was not limited to lipophilic regions of the biofilm.

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Section: Resultsmentioning

confidence: 97%

Rates of Sorption and Partitioning of Contaminants in River Biofilm

Headley

Gandrass

Kuballa

et al. 1998

Environ. Sci. Technol.

129

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“…Twenty-gram (equivalent dry weight) wet sediment samples (at water holding capacity) were placed in a capped glass flask (100 mL). Each sample was amended with 100 µL of methanol containing [U-ring- 14 C]atrazine and nonlabeled atrazine to yield final concentrations of 0, 0.01, and 10 mg of atrazine kg -1 soil and 6 Mbq per sample. Controls (not receiving atrazine) were amended with 100 µL of methanol.…”

Section: Methodsmentioning

confidence: 99%

“…Nair and Schnoor (13,20) showed that denitrifying or oxygen limited conditions in soils reduced atrazine biotransformation and mineralization. Wilber and Parkin (14) reported that second-order rate constants were in the range of (1-3) × 10 -5 L/mg VSS for biotransformation of atrazine under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions.…”

Section: Introductionmentioning

confidence: 99%

Rapid Atrazine Mineralization under Denitrifying Conditions by Pseudomonas sp. Strain ADP in Aquifer Sediments

Shapir

Mandelbaum

Jacobsen

1998

Environ. Sci. Technol.

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Atrazine mineralization was studied in sediments taken from a shallow aquifer underlying a cornfield continuously receiving atrazine and terbuthylazine. In contrast to previous publications indicating slow or nonexisting mineralization rates under denitrifying conditions in sediments, we hereby report on the ability of the bacterium Pseudomonas sp. strain ADP to rapidly mineralize atrazine in aquifer sediments under nitrate reducing conditions. When atrazine was present in low concentrations (relevant to nonpoint sources such as agricultural application), the bacterium mineralized 55% and 75% of the atrazine in 2 and 4 days, respectively. When atrazine was present in high concentrations (relevant to spill sites), P. ADP mineralized 48% and 78% in 4 and 15 days, respectively. The present study indicates that bioaugmantation with an effective atrazine mineralizing bacterium such as P. ADP could yield high mineralization rates even under oxygen limited conditions and have a significant implication for bioremediation of atrazine in contaminated aquifers.

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“…The degradation of atrazine in surface soils has been reported to be slower under anaerobic conditions than under aerobic conditions Schnoor, 1992, 1994;Yanze-Kontchou and Gschwind, 1995). Wilber and Parkin (1995) observed no significant differences in the rate of atrazine degradation by aerobic, nitrate-reducing, sulfate-reducing, or methanogenic microbial cultures. The rate of atrazine degradation has been reported to be slower under lowoxygen conditions than under aerobic conditions in estuarine sediments (Jones et al, 1982) and wetland sediments (Chung et al, 1995;Ro and Chung, 1995).…”

Section: Introductionmentioning

confidence: 96%

“…The addition of a carbon source has been shown to enhance the degradation of several compounds under various conditions. Examples include the accelerated degradation of atrazine metabolites (Assaf and Turco, 1994) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) under sulfate-reducing or methanogenic conditions (Gibson and Suflita, 1990), atrazine and alachlor [2-chloro-2′,2′-diethyl-N-(methoxymethyl)acetanilide] under denitrifying conditions (Wilber and Parkin, 1995), and total triazine in atrazine-spiked sediments under anaerobic conditions (Chung et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Atrazine, Deethylatrazine, and Deisopropylatrazine Persistence Measured in Groundwater in Situ under Low-Oxygen Conditions

Papiernik

Spalding

1998

J. Agric. Food Chem.

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The degradation of atrazine [2-chloro-4-(ethylamino)-6-isopropylamino-1,3,5-triazine], deethylatrazine [DEA; 2-amino-4-chloro-6-(isopropylamino)-1,3,5-triazine], and deisopropylatrazine [DIA; 2-amino-4-chloro-6-(ethylamino)-1,3,5-triazine] was assessed under limited oxygen conditions using in situ microcosms. Denitrification was induced in a shallow sand and gravel aquifer to measure the potential for degradation of atrazine, DEA, and DIA under low-O 2 conditions. The dissolved oxygen content decreased from 7-8 mg/L to e1 mg/L within 4 days and remained j3 mg/L for the remainder of the 45-day experiment. Atrazine, DEA, and DIA concentrations (normalized to the bromide concentration at each sampling time to account for dilution) did not show a significant decrease with time, indicating that these compounds are relatively stable under the low-O 2 conditions induced in the aquifer. Although removal of one alkyl group has been proposed as the rate-limiting step in atrazine degradation, no transformation of either monodealkylated metabolite (DEA or DIA) was observed in this study.

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Kinetics of Alachlor and Atrazine Biotransformation Under Various Electron Acceptor Conditions

Cited by 5 publications

References 0 publications

Rates of Sorption and Partitioning of Contaminants in River Biofilm

Rates of Sorption and Partitioning of Contaminants in River Biofilm

Rapid Atrazine Mineralization under Denitrifying Conditions by Pseudomonas sp. Strain ADP in Aquifer Sediments

Atrazine, Deethylatrazine, and Deisopropylatrazine Persistence Measured in Groundwater in Situ under Low-Oxygen Conditions

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