Marianne Bischoff

University of Georgia, Athens, GA, United States

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Publications (26)64.34 Total impact

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    ABSTRACT: The use of single-wall carbon nanotubes (SWNTs) in manufacturing and biomedical applications is increasing at a rapid rate; however data on the effects of a potential environmental release of the materials remain sparse. In this study, soils with either low or high organic matter contents as well as pure cultures of E. coli are challenged with either raw As-Produced SWNTs (AP-SWNTs) or SWNTs functionalized with either polyethyleneglycol (PEG-SWNTs) or m-polyaminobenzene sulfonic acid (PABS-SWNTs). To mimic chronic exposure, the soil systems were challenged weekly for six weeks; microbial activities and community structures for both the prokaryote and eukaryote community were evaluated. Results show that repeated applications of AP-SWNTs can affect microbial community structures and induce minor changes in soil metabolic activity in the low organic matter systems. Toxicity of the three types of SWNTs was also assessed in liquid cultures using a bioluminescent E. coli-O157:H7 strain. Although decreases in light were detected in all treated samples, low light recovery following glucose addition in AP-SWNTs treatment and light absorption property of SWNTs particles suggest that AP-SWNTs suppressed metabolic activity of the E. coli, while the two functionalized SWNTs are less toxic. The metals released from the raw forms of SWNTs would not play a role in the effects seen in soil or the pure culture. We suggest that sorption to soil organic matter plays a controlling role in the soil microbiological responses to these nanomaterials.
    Environmental Science & Technology 11/2012; · 5.26 Impact Factor
  • R F Turco, M Bischoff, Z H Tong, L Nies
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    ABSTRACT: A fundamental lack of data on the potential impacts of carbon based nanomaterials on natural ecosystems currently exists. The gap between what we know about environmental impacts and new products that may contain nanomaterials continues to get wider especially related to knowledge about nanocomposites. In this paper we present ideas and concerns about the current state of knowledge on nanomaterials in the environment and present a number of points about what recent work has provided us about the novel materials.
    Current opinion in biotechnology 08/2011; 22(4):527-32. · 7.82 Impact Factor
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    ABSTRACT: To better protect consumers from exposure to produce contaminated with Escherichia coli, the potential transfer of E. coli from manure or irrigation water to plants must be better understood. We used E. coli strains expressing bioluminescence (E. coli O157:H7 lux) or multiantibiotic resistance (E. coli²(+)) in this study. These marked strains enabled us to visualize in situ rhizosphere colonization and metabolic activity and to track the occurrence and survival of E. coli in soil, rhizosphere, and phyllosphere. When radish and lettuce seeds were treated with E. coli O157:H7 lux and grown in an agar-based growth system, rapid bacterial colonization of the germinating seedlings and high levels of microbial activity were seen. Introduction of E. coli²(+) to soil via manure or via manure in irrigation water showed that E. coli could establish itself in the lettuce rhizosphere. Regardless of introduction method, 15 days subsequent to its establishment in the rhizosphere, E. coli²(+) was detected on the phyllosphere of lettuce at an average number of 2.5 log CFU/g. When E. coli²(+) was introduced 17 and 32 days postseeding to untreated soil (rather than the plant surface) via irrigation, it was detected at low levels (1.4 log CFU/g) on the lettuce phyllosphere 10 days later. While E. coli²(+) persisted in the bulk and rhizosphere soil throughout the study period (day 41), it was not detected on the external portions of the phyllosphere after 27 days. Overall, we find that E. coli is mobile in the plant system and responds to the rhizosphere like other bacteria.
    Journal of food protection 11/2010; 73(11):2001-9. · 1.83 Impact Factor
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    ABSTRACT: An enrichment culture approach was used to isolate a pure culture of the yeast Lipomyces kononenkoae, which had the ability to grow on the herbicide picloram. The yeast rapidly and completely degraded 50 microg mL(-1) picloram by 48 h of growth. While L. kononenkoae was found to use both N atoms of picloram as a sole nitrogen source for growth, it failed to mineralize the herbicide or use it as a sole C source. Product analysis done using LC-ESI-MS indicated that biodegradation of picloram by L. kononenkoae proceeds via a didechlorinated, dihydroxylated, pyridinecarboxylic acid derivative. Our results are consistent with the hypothesis that the majority of picloram degradation in the soil is likely due to microbial catabolic processes.
    Journal of Agricultural and Food Chemistry 07/2009; 57(11):4878-82. · 2.91 Impact Factor
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    ABSTRACT: The nascent state of the nanoproduct industry calls for important early assessment of environmental impacts before significant releases have occurred. Clearly, the impact of manufactured nanomaterials on key soil processes must be addressed so that an unbiased discussion concerning the environmental consequences of nanotechnology can take place. In this study, soils were treated with either 1 microg C60 g(-1) soil in aqueous suspension (nC60) or 1000 microg C60 g(-1) soil in granularform, a control containing equivalent tetrahydrofuran residues as generated during nC60 formation process or water and incubated for up to 180 days. Treatment effects on soil respiration, both basal and glucose-induced, were evaluated. The effects on the soil microbial community size was evaluated using total phospholipid derived phosphate. The impact on community structure was evaluated using both fatty acid profiles and following extraction of total genomic DNA, by DGGE after PCR amplification of total genomic DNA using bacterial variable V3 region targeted primers. In addition, treatment affects on soil enzymatic activities for beta-glucosidase, acid-phosphatase, dehydrogenase, and urease were followed. Our observations show that the introduction of fullerene, as either C60 or nC60, has little impact on the structure and function of the soil microbial community and microbial processes.
    Environmental Science and Technology 05/2007; 41(8):2985-91. · 5.26 Impact Factor
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    ABSTRACT: The impact on the microbial community of long-term environmental exposure to metal and organic contamination was investigated. Twenty-four soil samples were collected along a transect dug in soils contaminated with road paint and paint solvents, mainly toluene. Chemical analysis along the transect revealed a range from high to low concentrations of metals (lead and chromium) and organic solvent compounds. Principal components analysis of microbial community structure based on denaturing gradient gel electrophoresis of the V3 region of the 16S rRNA gene and fatty acid methyl esters derived from phospholipids (phospholipid fatty acid analysis) showing samples with similar fingerprints also had similar contaminant concentrations. There was also a weak positive correlation between microbial biomass and the organic carbon concentration. Results indicated that microbial populations are present despite some extreme contaminant levels in this mixed-waste contaminated site. Nucleotide sequence determination of the 16S rRNA gene indicated the presence of phylogenetically diverse bacteria belonging to the alpha-, beta-, gamma-, and delta-Proteobacteria, the high and low G + C Gram-positive bacteria, green nonsulfur, OP8, and others that did not group within a described division. This indicates that soils contaminated with both heavy metals and hydrocarbons for several decades have undergone changes in community composition, but still contain a phylogenetically diverse group of bacteria (including novel phylotypes) that warrant further investigation.
    Microbial Ecology 03/2006; 51(2):209-19. · 3.28 Impact Factor
  • M Bischoff, Linda S Lee, R F Turco
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    ABSTRACT: In a recent study on the degradation of N,N'-dibutylurea (DBU), a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, degradation half-lives of 1.4-46.5 days were observed across several soils incubated at various combinations of soil moisture potential (-0.03 and -0.1 MPa) and temperature (23, 33, and 44 degrees C) for a single DBU application of 0.08 and 0.8 microg g(-1) (Lee et al. 2004). However, Benlate can be applied as often as every 7 days resulting in the repeated application of DBU likely to be present in the Benlate over a growing season. In this study, the effect of seven repeated DBU applications on mineralization rate was investigated in two soils, which encompass the range in rates previously observed. For the slower degrading soil, repeated DBU application increased mineralization from 0.029 to 0.99 day(-1) at the 0.08 microg g(-1) rate, and 0.037 to 0.89 day(-1) at the 0.8 microg g(-1) rate. For the faster degrading soil, effects on mineralization of repeated DBU applications were small to negligible. For the latter soil, the effect on mineralization of applied DBU concentrations from 0.0008 to 80 microg g(-1) was also investigated. Mineralization rates decreased from 0.43 to 0.019 day(-1) with increasing DBU concentrations. However, the amount of DBU mineralized by day 70 was similar across concentrations and averaged 83% of applied. Microbial respiration was not affected by increasing DBU concentrations. These findings support the supposition that DBU is readily degraded by soil microorganisms, thus unlikely to accumulate in agricultural soils.
    Biodegradation 07/2005; 16(3):265-73. · 2.17 Impact Factor
  • Wei Shi, Marianne Bischoff, Ronald Turco, Allan Konopka
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    ABSTRACT: Understanding indigenous microbial function in contaminated soil is crucial to the successful development and use of bioremediation technologies. We measured the catabolic diversity of indigenous microbial communities in soils with a 30-yr history of Pb, Cr, and hydrocarbon (HC) contamination using a modified substrate-induced respiration method. There were characteristic differences of microbial respirations in the response of highly versus less contaminated soils to the range of organic substrates used. The catabolic response to glucose as compared to succinic acid was approximately 1:5 in less contaminated soils, but 1:25 in highly contaminated soils. In contrast, the response ratio to glucose versus aromatics was about 1:0.4 in less contaminated soils and 1:1 in highly contaminated soils. Principal components analysis (PCA) of the responses confirmed that catabolic diversity differed between highly and less contaminated soils. Univariate analysis also indicated that catabolic diversity was reduced in highly contaminated soils. This catabolic difference was strongly associated with the alteration of microbial community composition. Statistical analyses suggested that the variation in microbial community catabolic diversity was attributed to HCs more than to Pb and Cr.
    Environmental Science and Technology 05/2005; 39(7):1974-9. · 5.26 Impact Factor
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    ABSTRACT: Understanding the dissipation rates of chemicals in unsaturated and saturated zones of subsurface soils will help determine if reductions of concentrations to acceptable levels will occur. Chemical properties and microbial biomass and activity were determined for the surface (0-15 cm), lower root (50-105 cm), and vadose (175-220 cm) zones in a Huntington silty clay loam (Fluventic Hapludoll) collected from an agricultural field near Piketon, OH. The rates of sorption, mineralization, and transformation (formation of bound residues and metabolites) of atrazine were determined. Microbial activity was estimated from the mineralization of (14)C-benzoate. We observed decreased levels of nutrients (total organic carbon, N, and P) and microbial biomass with depth, while activity as measured with benzoate metabolism was higher in the vadose zone than in either the surface or the root zones. Sorption coefficients (K(f)) declined from 8.17 in the surface to 3.31 in the vadose zone. Sorption was positively correlated with organic C content. Rates of atrazine mineralization and bound residues formation were, respectively, 12-2.3-fold lower in the vadose than in the surface soil. Estimated half-lives of atrazine ranged from 77 to 101 days in the surface soil, but increased to over 900 days in the subsurface soils. The decreased dissipation of atrazine with increasing depth in the profile is the result of decreased microbial activity toward atrazine, measured either as total biomass or as populations of atrazine-degrading microorganisms. The combination of reduced dissipation and low sorption indicates that there is potential for atrazine movement in the subsurface soils.
    Journal of Agricultural and Food Chemistry 01/2005; 52(24):7382-8. · 2.91 Impact Factor
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    ABSTRACT: N,N'-Dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed as one cause for crop damage that growers claim to have occurred from the use of Benlate 50 DF fungicide. This study assessed DBU formation upon (1). application of n-butyl-1-[(14)C]butylisocyanate (BIC), the immediate precursor to DBU formation, in four soils at two water potentials (0.03 and 0.1 MPa) and (2). application of benomyl butyl-1-(14)C-benomyl enriched Benlate DF and SP fungicides to two soils at various combinations of negative water potential (0.03 or 0.1 MPa) and temperature (23 or 33 degrees C). Parent compounds, metabolites, and (14)CO(2) were tracked using chromatographic analysis with radioassay and UV detection, liquid scintillation counting, and postextraction oxidation of the soil. At 0.03 MPa in all four BIC-treated soils, DBU formation was never detected. At 0.1 MPa, DBU was detected in two soils, but at concentrations <3.6 microg kg(-)(1) (0.3 wt % of applied BIC). In both soils treated with benomyl formulations, DBU formation was observed with only Benlate 50 DF application at 0.03 MPa and 23 degrees C, which was followed by rapid dissipation of DBU. The maximum concentration observed was 0.41 microg g(-)(1) (0.65 wt % of applied benomyl at 62.8 microg g(-)(1)), which is well below levels currently reported to cause adverse effects to plants. Combined benomyl and carbendazim half-lives in soils across treatments were 2-3 months. This study demonstrated that further production and accumulation of DBU in soils after Benlate application or from residual benomyl remaining in the soil are highly unlikely and that persistence of any DBU in soils is likely to be short-lived.
    Journal of Agricultural and Food Chemistry 02/2004; 52(4):747-54. · 2.91 Impact Factor
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    ABSTRACT: N,N'-dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed to cause crop damage after the use of Benlate 50 DF fungicide (DuPont, Wilmington, DE). Our research focused on DBU persistence after application into soil. We assessed DBU persistence on direct application of DBU (carbonyl-(14)C) at two concentrations (0.08 and 0.8 microg DBU kg(-1)) to seven soils and two potting mixes in soil microcosms incubated at various combinations of soil water potential (-0.03 or -0.1 MPa) and temperature (23, 33, 44 degrees C). For two soils at a subset of treatment variables we assessed DBU persistence in the presence of Benlate DF and SP fungicide formulations. Parent compounds, metabolites, and (14)CO(2) were tracked using chromatographic analysis with radioassay and UV detection, liquid scintillation counting, and post-extraction oxidation of the soil. DBU degradation was primarily microbial and for most soil-treatment combinations, half-lives were less than 2 wk. DBU degradation was retarded at the lower soil water potential and enhanced at 33 degrees C. In the presence of the formulation, DBU degradation was slower for one soil type. The longest half-life observed in any case was less than 7 wk; therefore, long-term persistence of DBU applied to soils through a Benlate application is very unlikely.
    Journal of Environmental Quality 01/2004; 33(5):1771-8. · 2.35 Impact Factor
  • Journal of Environmental Quality - J ENVIRON QUAL. 01/2004; 33(5).
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    ABSTRACT: Microbial degradation of fungicides on leaf surfaces after repeated applications to turfgrass was investigated. Prior andcurrent work in our laboratory has identified two characteristicsof the turfgrass leaf system that may contribute to the enhanceddegradation of fungicides after repeated application to turfgrass:(1) The leaf surface is rich in microorganisms (108 g-1 dr wt leaf), and (2) Leaf surface microorganisms may respond to repeated fungicide applications in a manner consistentwith the phenomena of enhanced biodegradation. Field studies wereconducted on Penncross' creeping bentgrass with four fungicidesrepresenting three chemical families applied either two or eight times in one growing season. Biodegradation was estimated using data from both a field study and a parallel laboratory study thatfollowed the fate of 14C-labelled fungicides. For the laboratory incubations, the locations of the residual 14C fungicides were estimated using a sequential extraction protocolthat fractionated the materials into three pools: available,retained and bound. Data from both the field and laboratory studyrefuted our hypothesis that enhanced biodegradation would developfollowing repeated applications of the fungicides onto the leafsurface. Our studies support a conclusion that a two-stagephysical sorption process leads to plant incorporation and thiscontrols most of the fungicide's fate. Thus, our data suggestthat microbial activity plays a less important part in theprocess than would be indicated by considering the size of themicrobial population on the leaves.
    Water Air and Soil Pollution 12/2002; 142(1):311-326. · 1.75 Impact Factor
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    ABSTRACT: Microbial community composition and activity were characterized in soil contaminated with lead (Pb), chromium (Cr), and hydrocarbons. Contaminant levels were very heterogeneous and ranged from 50 to 16,700 mg of total petroleum hydrocarbons (TPH) kg of soil(-1), 3 to 3,300 mg of total Cr kg of soil(-1), and 1 to 17,100 mg of Pb kg of soil(-1). Microbial community compositions were estimated from the patterns of phospholipid fatty acids (PLFA); these were considerably different among the 14 soil samples. Statistical analyses suggested that the variation in PLFA was more correlated with soil hydrocarbons than with the levels of Cr and Pb. The metal sensitivity of the microbial community was determined by extracting bacteria from soil and measuring [(3)H]leucine incorporation as a function of metal concentration. Six soil samples collected in the spring of 1999 had IC(50) values (the heavy metal concentrations giving 50% reduction of microbial activity) of approximately 2.5 mM for CrO(4)2- and 0.01 mM for Pb2+. Much higher levels of Pb were required to inhibit [14C]glucose mineralization directly in soils. In microcosm experiments with these samples, microbial biomass and the ratio of microbial biomass to soil organic C were not correlated with the concentrations of hydrocarbons and heavy metals. However, microbial C respiration in samples with a higher level of hydrocarbons differed from the other soils no matter whether complex organic C (alfalfa) was added or not. The ratios of microbial C respiration to microbial biomass differed significantly among the soil samples (P < 0.05) and were relatively high in soils contaminated with hydrocarbons or heavy metals. Our results suggest that the soil microbial community was predominantly affected by hydrocarbons.
    Applied and Environmental Microbiology 08/2002; 68(8):3859-66. · 3.95 Impact Factor
  • W Shi, M Bischoff, R Turco, A Konopka
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    ABSTRACT: The inhibitory effects of heavy metals upon microbial populations and the factors limiting microbial activity and growth were determined in soils that had been contaminated with lead (Pb) or chromium (Cr) for more than 40 years. Total Cr and Pb concentrations were 260,000 and 10,000 mg kg−1 soil in Cr- and Pb-contaminated soils, respectively. The tolerance of bacteria extracted from soil particles to Pb or Cr was assayed by measuring the incorporation of 3H-leucine into macromolecules at a series of CrO42− or Pb2+ concentrations. IC50 (heavy-metal concentration giving 50% reduction of microbial 3H-leucine incorporation compared to the control) for the two metals was similar in the two soils, despite their differences in metal contamination; the IC50 values were 4 and 0.02 mM for CrO42− and Pb2+, respectively. Stimulation of microbial activity and biomass by organic C was measured in microcosms over 56 days. The adverse effects of Cr and Pb were characterized in terms of the ratio of microbial biomass C to soil organic C, basal respiration per unit microbial biomass (qCO2), and the ratio of substrate-responsive respiration to microbial biomass C (substrate-responsive qCO2). Ratios of microbial biomass C to soil organic C were small: 0.42% in Cr-contaminated soil and 0.36% in Pb-contaminated soil. Values of qCO2 and substrate-responsive qCO2 were significantly higher in Pb- than in Cr-contaminated soils (P<0.01). The microcosm results indicate that Cr and Pb decreased microbial activities and led to the accumulation of soil organic C, and that Pb posed greater stress to soil microbes than Cr.
    Applied Soil Ecology. 01/2002;
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    ABSTRACT: Microbial biomass, size and community structure along with an estimate of microbial activity and soil chemical parameters were determined at three depths in two soils (e.g. sandy loam Ultic Hapludalf and silt loam Mollic Hapludalf) replicated three times under one winter and summer season. Microbial biomass and community structure were estimated from phospholipid-PO4 content and fatty acid methyl ester (FAME) measurements. Microbial activity and assimilative capacity were estimated using a -acetate incorporation into phospholipids and by incubating the soil samples at the average winter and summer temperatures, 3 and 20 °C, respectively. We found that the size of the microbial biomass in both the surface and the subsurface soils was not significantly affected by the seasonal variation but activity increased by as much as 83% at the summer temperatures in the surface soil. We demonstrated using FAME analysis that for both soils seasonal changes in the subsurface microbial community occurred. These findings suggest that winter conditions will shift the population activity level in both the surface and subsurface systems and the biochemical structure of the community in the subsurface. In all cases, the inorganic chemical properties of the soil, as a function of season, remained constant. The greatly increased activity of microbial population at the higher temperature will favor the capacity of the system to utilize nutrients or organic materials that may enter soil. During low temperature seasons the capacity of either surface or subsurface soils to assimilate materials is generally diminished but the reduction reflects changes in metabolism and not a reduced biomass size.
    Applied Soil Ecology. 01/2002;
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    ABSTRACT: Microbial community diversity, potential microbial activity, and metal resistance were determined in three soils whose lead contents ranged from 0.00039 to 48 mmol of Pb kg of soil-1. Biomass levels were directly related to lead content. A molecular analysis of 16S rRNAs suggested that each soil contained a complex, diverse microbial community. A statistical analysis of the phospholipid fatty acids indicated that the community in the soil having the highest lead content was not related to the communities in the other soils. All of the soils contained active microbial populations that mineralized [14C]glucose. In all samples, 10 to 15% of the total culturable bacteria were Pb resistant and had MIC of Pb for growth of 100 to 150 &mgr;M.
    Applied and Environmental Microbiology 06/1999; 65(5):2256-9. · 3.95 Impact Factor
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    ABSTRACT:  The influence of tree leaf amendment and N fertilization on soil quality in turfgrass environments was evaluated. Our objective was to assess changes in soil quality after additions of leaf materials and N fertilization by monitoring soil chemical and physical parameters, microbial biomass and soil enzymes. Established perennial ryegrass (Lolium perenne) plots were amended annually with maple (Acer spp.) leaves at three different rates (0, 2240, and 4480 kg ha–1 year–1) and treated with three nitrogen rates (0, 63, and 126 kg N ha–1 year–1). Tree leaf mulching did not significantly affect water infiltration or bulk density. However, trends in the data suggest increased infiltration with increasing leaf application rate. Tree leaf mulching increased total soil C and N at 0–1.3 cm depth but not at 1.3–9.0 cm. Extracted microbial phospholipid, an indicator of microbial biomass size, ranged from 28 to 68 nmol phospholipid g–1 soil at the 1.3–9.0 cm depth. The activity of β-glucosidase estimated on samples from 0–1.3 cm and 1.3–9.0 cm depths, and dehydrogenase activity estimated on samples from 1.3–9.0 cm were significantly increased by leaf mulching and N fertilizer application. Changes in microbial community composition, as indicated by phospholipid fatty acid methyl ester analysis, appear to be due to seasonal variations and did not reflect changes due to N or leaf amendment treatments. There were no negative effects of tree leaf mulching into turfgrass and early data suggest this practice will improve soil chemical, physical, and biological structure.
    Biology and Fertility of Soils 01/1999; 29(1):55-61. · 2.51 Impact Factor
  • Brandon C. Grigg, Marianne Bischoff, Ronald F. Turco
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    ABSTRACT: In most pesticide-contaminated agrichemical facilities, atrazine is found in combination with other widely used agricultural chemicals, and remediation strategies must account for the multiple-contaminant environment. The ability of an atrazine-mineralizing culture to degrade other s-triazines in liquid culture was evaluated. Cyanazine and simazine, added to liquid culture, either alone or combined with atrazine, were degraded in 6 days. Cyanazine was degraded to persistent metabolite(s), as yet unidentified. Metribuzin was not degraded. The culture completely degraded atrazine in the presence of cocontaminants including alachlor, metolachlor, and trifluralin. Atrazine degradation was not affected when cocontaminant herbicides were introduced singly. Mixtures of cocontaminants increased half-life values of atrazine plus hydroxyatrazine 2−3 times. Nitrate presence did not affect atrazine. These results suggest that our mixed culture could be successfully used to bioaugment s-triazine contaminated systems, in the presence of nitrate and commonly detected cocontaminant herbicides. Keywords: Biodegradation; atrazine; simazine; cyanazine; cocontaminants
    Journal of Agricultural and Food Chemistry - J AGR FOOD CHEM. 03/1997; 45(3).
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    ABSTRACT: The molecular complexity of imazaquin and presence of ionizable functional groups limits the ability to predict sorption behavior from single soil parameters such as organic carbon content. Partition coefficients (Kp) for both neutral and anionic forms of imazaquin as well as the effects of solution ionic strength and composition were investigated to more adequately describe sorption of imazaquin in soil. Soils representing a range of characteristics were evaluated, including soils with permanent negative or variable surface charge. Imazaquin retention resulted from combined sorption for the neutral (Kocn, 1,110 ± 80 L/kg) and anionic (Koc,a, 38 ± 20 L/kg) forms. Imazaquin sorption was best correlated to soil organic carbon content and soil-solution pH. However, results indicated that positively charged Fe2+ and Al3+ oxyhydroxides contribute to sorption of the organic anion; thus mineral surfaces contributed to sorption in soils with low organic carbon content. The effects of electrolyte matrices on imazaquin sorption were accounted for by concomitant changes in pH. However, enhanced imazaquin sorption was observed with increasing ionic strength for soils where pH-induced changes in speciation were negligible, indicating the role of mechanisms other than weak hydrophobic interactions. Addition of H2 PO significantly decreased imazaquin sorption, especially in weathered soils.
    Environmental Toxicology and Chemistry 02/1997; 16(3):397 - 404. · 2.62 Impact Factor