Soil Movement and Persistence of Triazine Herbicides

Koskinen, William C.

doi:10.1016/b978-044451167-6.50027-1

Cited by 7 publications

(7 citation statements)

References 324 publications

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“…The soil with no previous atrazine exposure had a DT 50 of 16.9 d (Table 1; Figure 1). The relatively minor difference between our ''sterile'' soil samples and the nonsterile soil with no previous atrazine exposure was not expected, although atrazine persistence has been reported to be highly variable, with DT 50 ranging from 14 to 112 d, with a mean DT 50 of 36 6 25 d (Koskinen and Banks 2008). A possible explanation for our observed results is that the mercuric chloride was not effective in killing all microbes capable of degrading atrazine.…”

Section: Resultscontrasting

confidence: 64%

Effect of Soil pH and Previous Atrazine Use History on Atrazine Degradation in a Tennessee Field Soil

2010

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Field studies examined the interaction of soil pH with differing levels of atrazine exposure over 4 yr. Soil pH was 5.2 to 7.1 with atrazine exposures ranging from none (0) to eight applications over a 4-yr period (for each year, one application at planting and one early postemergence). The entire plot area was uniformly managed to reduce potential confounding effects due to cropping history, tillage, and other factors. Soil from all plots previously treated with atrazine displayed rapid atrazine dissipation, with half-lives under laboratory conditions being less than 4 d in plots of pH 5.5 or greater and less than 8 d in the field. Soil pH had a marked effect, with slower atrazine dissipation in those plots that had a pH 5.5 or less. This effect of pH and previous atrazine history was consistent in laboratory and field environments. Implications of these findings include probable reduction in weed control due to more rapid atrazine dissipation and potentially reduced loadings into surface water due to this phenomenon.

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Section: Resultscontrasting

confidence: 64%

Effect of Soil pH and Previous Atrazine Use History on Atrazine Degradation in a Tennessee Field Soil

2010

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“…Krutz et al 11 also found that there was more DEA formed compared with DIA in non‐adapted soils from Colorado and Mississippi. DEA and DIA bind loosely to soil, and DEA has been frequently found in soil water at greater depths and at higher concentrations in groundwater than atrazine or DIA 31. Early studies showed that more 14 CO 2 was released when the radiolabel was on the aminoethyl substituent than when it was in the ring or on the aminoisopropyl substituent 21.…”

Section: Resultsmentioning

confidence: 99%

Agronomic and environmental implications of enhanceds-triazine degradation

et al. 2010

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environmental implications of enhanced s-triazine degradation" (2010 AbstractNovel catabolic pathways enabling rapid detoxification of s-triazine herbicides have been elucidated and detected at a growing number of locations. The genes responsible for s-triazine mineralization, i.e. atzABCDEF and trzNDF, occur in at least four bacterial phyla and are implicated in the development of enhanced degradation in agricultural soils from all continents except Antarctica. Enhanced degradation occurs in at least nine crops and six crop rotation systems that rely on s-triazine herbicides for weed control, and, with the exception of acidic soil conditions and s-triazine application frequency, adaptation of the microbial population is independent of soil physiochemical properties and cultural management practices. From an agronomic perspective, residual weed control could be reduced tenfold in s-triazine-adapted relative to non-adapted soils. From an environmental standpoint, the off-site loss of total s-triazine residues could be overestimated 13-fold in adapted soils if altered persistence estimates and metabolic pathways are not reflected in fate and transport models. Empirical models requiring soil pH and s-triazine use history as input parameters predict atrazine persistence more accurately than historical estimates, thereby allowing practitioners to adjust weed control strategies and model input values when warranted. Published

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“…It is one of several chemicals, including simazine and propazine, that falls under the triazine class of herbicides due to their similar mechanisms of toxicity in weeds. (1) Structurally, atrazine is a nitrogenous ring with chloride, ethylamine, and isopropylamine moieties. The synthetic molecule is an odorless, white powder in its pure form.…”

Section: Introductionmentioning

confidence: 99%

Mode of Growth and Temperature Dependence on Expression of Atrazine-degrading Genes inPseudomonassp. strain ADP Biofilms

et al. 2018

Preprint

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25Bacterial strain Pseudomonas sp. strain ADP is capable of metabolizing atrazine, a synthetic 26 herbicide, and uses atrazine as a sole nitrogen source for growth. The microbe completely 27 mineralizes the substrate in a catabolic pathway comprised of six enzymatic steps. All enzymes, 28 AtzA-AtzF, encoded by corresponding genes, AtzA-AtzF, are located on a self-transmissible 29 plasmid, pADP-1. (Souza, M. L., Wackett, L.P., and Sadowsky, M.J Appl. and Environ. 30 Microbiol. 64 (6): [2323][2324][2325][2326] 1998) RT-qPCR was used to differentiate gene expression in 31 atrazine-degrading genes in Pseudomonas sp. strain ADP cells grown as suspended cells and as 32 biofilms. Relative gene expression was also evaluated for biofilms grown at 25 o C, 30 o C, and 33 37 o C. Complementary atrazine kinetic data was collected using GC-MS for both modes of 34 growth and temperature variance. No significant difference in expression was observed for all 35 atrazine-degrading genes in biofilm-mediated cells relative to planktonic cells, suggesting neither 36 decreased or increased catabolic activity at the mRNA level. In contrasting experiments 37 concerning biofilm growth, expression was downregulated at 37 o C for genes AtzA, AtzB, and 38 AtzC and upregulated for genes AtzD, AtzE, AtzF, signifying Pseudomonas sp. strain ADP 39 biofilms catabolic activity may change in response to substantial temperature changes. Gradual 40 decreases in atrazine concentration were apparent in cells grown in shake flasks, while biofilm-41 mediated cells showed transient increases and decreases in reactor effluent. The complex 42 extracellular matrix components, quorum sensing, and genetic transfer may account for 43 accumulation and rapid degradation of atrazine. The data collected suggest biofilm-mediated 44 bioremediation may give insight into catabolic activity and atrazine degradation potential. 45 46 3 Importance 47 48Atrazine is the second most applied herbicide in the United States. It is applied to crops 49 including sorghum, corn, and sugarcane to prevent the growth of broad-leaved weeds. Once 50 used, it can permeate the soil and contaminate proximal groundwater sources, which provide 51 drinking water for over 90-million people. The Environmental Protection Agency sets the 52 maximum contaminant level at 3 parts per billion for atrazine in drinking water, however this is 53 frequently exceeded in rural regions which presents a public safety concern. Atrazine is an 54 endocrine disruptor compound and a suspected teratogen in humans and freshwater species, 55 respectively. This research is significant in evaluating the use an atrazine-degrading strain, 56Pseudomonas sp. strain ADP, grown in a biofilm mode of growth to increase the degradation 57 potential compared to suspended cells. Our results concerning expression and kinetics will aid 58 the development of biofilm reactors for ex situ bioremediation and understanding environmental 59 biofilms. 60 61 Introduction 62 63 Atrazine is a ubiquitous herbicide used to contro...

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Soil Movement and Persistence of Triazine Herbicides

Cited by 7 publications

References 324 publications

Effect of Soil pH and Previous Atrazine Use History on Atrazine Degradation in a Tennessee Field Soil

Effect of Soil pH and Previous Atrazine Use History on Atrazine Degradation in a Tennessee Field Soil

Agronomic and environmental implications of enhanceds-triazine degradation

Mode of Growth and Temperature Dependence on Expression of Atrazine-degrading Genes inPseudomonassp. strain ADP Biofilms

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