Phytoextraction and biodegradation of atrazine by Myriophyllum spicatum and evaluation of bacterial communities involved in atrazine degradation in lake sediment.

PubMed

Qu, Mengjie; Li, Na; Li, Huidong; Yang, Tewu; Liu, Wei; Yan, Yupeng; Feng, Xionghan; Zhu, Duanwei

2018-06-14

The accumulation of atrazine in lake sediments leads to persistent contamination, which may damage the succeeding submerged plants and create potential threats to the lake eco-environment. In this study, the degradation characteristics of atrazine and its detoxication by Myriophyllum spicatum and the associated bacterial community in lake sediments were evaluated. M. spicatum absorbed more than 18-fold the amount of atrazine in sediments and degraded atrazine to hydroxyatrazine (HA), deelthylatrazine (DEA), didealkylatrazine (DDA), cyanuric acid (CYA) and biuret. The formation of biuret suggested for the first time, the ring opening of atrazine in an aquatic plant. The residual rate of atrazine was 6.5 ± 2.0% in M. spicatum-grown sediment, which was significantly lower than the 18.0 ± 2.5% in unplanted sediments on day 60 (P < 0.05). Moreover, on day 15, the increase in contents of HA, CYA and biuret in M. spicatum-grown sediment indicated that M. spicatum promoted the degradation and removal of atrazine following rapid dechlorination. The colonization of M. spicatum and the addition of atrazine altered the structure of the dominant bacterial community in sediments, including effects on Nitrospirae and Acidobacteria. Based on the maximum amount among the genera of atrazine-degrading bacteria, Acetobacter was most likely responsible for the degradation of atrazine. Our findings reveal the natural attenuation of atrazine by aquatic organisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation and mineralization of atrazine by a soil bacterial isolate.

PubMed Central

Radosevich, M; Traina, S J; Hao, Y L; Tuovinen, O H

1995-01-01

An atrazine-degrading bacterial culture was isolated from an agricultural soil previously impacted by herbicide spills. The organism was capable of using atrazine under aerobic conditions as the sole source of C and N. Cyanuric acid could replace atrazine as the sole source of N, indicating that the organism was capable of ring cleavage. Ring cleavage was confirmed in 14CO2 evolution experiments with [U-14C-ring]atrazine. Between 40 and 50% of ring-14C was mineralized to 14CO2. [14C]biuret and [14C]urea were detected in spent culture media. Cellular assimilation of 14C was negligible, in keeping with the fully oxidized valence of the ring carbon. Chloride release was stoichiometric. The formation of ammonium during atrazine degradation was below the stoichiometric amount, suggesting a deficit due to cellular assimilation and metabolite-N accumulation. With excess glucose and with atrazine as the sole N source, free ammonium was not detected, suggesting assimilation into biomass. The organism degraded atrazine anaerobically in media which contained (i) atrazine only, (ii) atrazine and glucose, and (iii) atrazine, glucose, and nitrate. To date, this is the first report of a pure bacterial isolate with the ability to cleave the s-triazine ring structure of atrazine. It was also concluded that this bacterium was capable of dealkylation, dechlorination, and deamination in addition to ring cleavage. PMID:7887609

Estimation of the Potential for Atrazine Transport in a Silt Loam Soil

USGS Publications Warehouse

Eckhardt, D.A.V.; Wagenet, R.J.

1996-01-01

The transport potential of the herbicide atrazine (2-chloro-4-ethyl-6-isopropyl-s-triazine) through a 1-meter-thick root zone of corn (Zea mays L.) in a silty-loam soil in Kansas was estimated for a 22-year period (1972-93) using the one-dimensional water-flow and solute-transport model LEACHM. Results demonstrate that, for this soil, atrazine transport is directly related to the amount and timing of rain that follows spring applications of atrazine. Two other critical transport factors were important in wet years - [1] variability in atrazine application rate, and [2] atrazine degradation rates below the root zone. Results demonstrate that the coincidence of heavy rain soon after atrazine application can cause herbicide to move below the rooting zone into depths at which biodegradation rates are assumed to be low but are often unknown. Atrazine that reaches below the rooting zone and persists in the underlying soil can subsequently be transported into ground water as soil water drains, typically after the growing season. A frequency analysis of atrazine concentrations in subsurface drainage, combined with field data, demonstrates the relative importance of critical transport factors and confirms a need for definitive estimates of atrazine-degradation rates below the root zone. The analysis indicates that periodic leaching of atrazine can be expected for this soil when rainfall that exceeds 20 cm/mo coincides with atrazine presence in soil.

Effectiveness of narrow grass hedges in reducing atrazine runoff under different slope gradient conditions.

PubMed

Wang, Qinghai; Li, Cui; Chen, Chao; Chen, Jie; Zheng, Ruilun; Que, Xiaoe

2018-03-01

Atrazine is frequently detected in surface runoff and poses a potential threat to the environment. Grass hedges may minimize runoff loss of atrazine from crop fields. Therefore, the effectiveness of two grass hedges (Melilotus albus and Pennisetum alopecuroides) in controlling atrazine runoff was investigated using simulated rainfall on lands at different slope gradients (15 and 20%) in northern China. Results showed that a storm (40 mm in 1 h), occurring 4 h after atrazine application, caused a loss of 3% of the applied amount. Atrazine loss under 20% slope was significantly greater than that under 15% slope in control plots. Atrazine exports associated with the water fraction accounted for the majority of total loss. Pennisetum hedges were more efficient in controlling atrazine loss with runoff compared to Melilotus hedges. No significant difference in the capacity of grass hedges to reduce atrazine exports was observed between 15 and 20% slopes. These findings suggest grass hedges are effective in minimizing atrazine runoff in northern China, and Pennisetum hedges should be preferentially used on sloping croplands in similar climatic regions.

Atrazine remediation in wetland microcosms.

PubMed

Runes, H B; Bottomley, P J; Lerch, R N; Jenkins, J J

2001-05-01

Laboratory wetland microcosms were used to study treatment of atrazine in irrigation runoff by a field-scale-constructed wetland under controlled conditions. Three experiments, in which 1 ppm atrazine was added to the water column of three wetland, one soil control, and one water control microcosm, were conducted. Atrazine dissipation from the water column and degradate formation (deethylatrazine [DEA]; deisopropylatrazine [DIA]; and hydroxyatrazine [HA]) were monitored. Atrazine dissipation from the water column of wetland microcosms was biphasic. Less than 12% of the atrazine applied to wetland microcosms remained in the water column on day 56. Atrazine degradates were observed in water and sediment, with HA the predominant degradate. Analysis of day 56 sediment samples indicated that a significant portion of the initial application was detected as the parent compound and HA. Most probable number (MPN) assays demonstrated that atrazine degrader populations were small in wetland sediment. Wetland microcosms were able to reduce atrazine concentration in the water column via sorption and degradation. Based on results from this study, it is hypothesized that plant uptake contributed to atrazine dissipation from the water column.

Atrazine reduces reproduction in fathead minnow (Pimephales promelas)

USGS Publications Warehouse

Tillitt, D.E.; Papoulias, D.M.; Whyte, J.J.; Richter, C.A.

2010-01-01

Atrazine, the widely used herbicide, has shown to affect the hypothalamus-pituitary-gonad axis in certain vertebrate species, but few studies have examined reproductive effects of this chemical on fish. Our study was designed to evaluate a population endpoint (egg production) in conjunction with histological (e.g., gonad development) and biochemical (e.g., hormone production) phenotypes associated with atrazine exposure in fathead minnows. Adult virgin breeding groups of 1 male and 2 females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 ??g/L of atrazine in a flow-through diluter for 14 or 30 days. Total egg production was lower (19-39%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine treated fish were significant by 17-20 days of exposure. Reductions in egg production in atrazine treatment groups were most attributable to reduced numbers of spawning events with increased atrazine exposure concentrations. Gonad abnormalities were observed in both male and female fish of atrazine-exposed fish. Our results also indicate that atrazine reduces egg production through alteration of final maturation of oocytes. The reproductive effects observed in this study warrant further investigation and evaluation of the potential risks posed by atrazine, particularly feral populations of fish from streams in agricultural areas with high use of this herbicide. ?? 2010.

Distribution of atrazine and its phytoremediation by submerged macrophytes in lake sediments.

PubMed

Qu, Mengjie; Li, Huidong; Li, Na; Liu, Guanglong; Zhao, Jianwei; Hua, Yumei; Zhu, Duanwei

2017-02-01

We investigated sediments with high atrazine accumulation capability from 6 eutrophic lakes in Hubei Province of central China. Almost all lakes have atrazine in their sediments because of human activities. Honghu Lake and Liangzihu Lake were found to have higher levels of atrazine in sediment: 0.171 and 0.114 mg kg -1 , respectively. The results showed that lake sediments could adsorb atrazine six times faster than soils. The equilibrium partition coefficient of atrazine desorption (K Pd ) is much larger than the adsorption equilibrium partition coefficient (K Pa ) of atrazine, indicating that the residue of atrazine in water is easily immobilized by the sediments. Meanwhile, the incubation experiment showed that the removal rateof atrazine in Potamogeton crispus-planted and Myriophyllum spicatum-planted sediments reached >90%, while the rate in unplanted sediments was 77.2 ± 2.12% over 45 d. In unplanted sediment, the half-life of atrazine dissipation was 14.30 d, which was strongly enhanced by P. crispus and M. spicatum, greatly reducing the half-life to 8.60 and 9.72 d, respectively. These two submerged macrophytes are considered to be potential tools in the remediation of atrazine-contaminated sediments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Occurrence, diversity and community structure of culturable atrazine degraders in industrial and agricultural soils exposed to the herbicide in Shandong Province, P.R. China.

PubMed

Bazhanov, Dmitry P; Li, Chengyun; Li, Hongmei; Li, Jishun; Zhang, Xinjian; Chen, Xiangfeng; Yang, Hetong

2016-11-08

Soil populations of bacteria rapidly degrading atrazine are critical to the environmental fate of the herbicide. An enrichment bias from the routine isolation procedure prevents studying the diversity of atrazine degraders. In the present work, we analyzed the occurrence, diversity and community structure of soil atrazine-degrading bacteria based on their direct isolation. Atrazine-degrading bacteria were isolated by direct plating on a specially developed SM agar. The atrazine degradation genes trzN and atzABC were detected by multiplex PCR. The diversity of atrazine degraders was characterized by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) genotyping followed by 16S rRNA gene phylogenetic analysis. The occurrence of atrazine-degrading bacteria was also assessed by conventional PCR targeting trzN and atzABC in soil DNA. A total of 116 atrazine-degrading isolates were recovered from bulk and rhizosphere soils sampled near an atrazine factory and from geographically distant maize fields. Fifteen genotypes were distinguished among 56 industrial isolates, with 13 of them representing eight phylogenetic groups of the genus Arthrobacter. The remaining two were closely related to Pseudomonas alcaliphila and Gulosibacter molinativorax and constituted major components of the atrazine-degrading community in the most heavily contaminated industrial plantless soil. All isolates from the adjacent sites inhabited by cogon grass or common reed were various Arthrobacter spp. with a strong prevalence of A. aurescens group. Only three genotypes were distinguished among 60 agricultural strains. Genetically similar Arthrobacter ureafaciens bacteria which occurred as minor inhabitants of cogon grass roots in the industrial soil were ubiquitous and predominant atrazine degraders in the maize rhizosphere. The other two genotypes represented two distant Nocardioides spp. that were specific to their geographic origins. Direct plating on SM agar enabled rapid isolation of atrazine-degrading bacteria and analysis of their natural diversity in soil. The results obtained provided evidence that contaminated soils harbored communities of genetically distinct bacteria capable of individually degrading and utilizing atrazine. The community structures of culturable atrazine degraders were habitat-specific. Bacteria belonging to the genus Arthrobacter were the predominant degraders of atrazine in the plant rhizosphere.

Stabilized filter-supported bilayer lipid membranes (BLMs) for automated flow monitoring of compounds of clinical, pharmaceutical, environmental and industrial interest

PubMed Central

Siontorou, Christina G.

1997-01-01

This paper describes the results of analytical applications of electrochemical biosensors based on bilayer lipid membranes (BLMs) for the automated rapid and sensitive flow monitoring of substrates of hydrolytic enzymes, antigens and triazine herbicides. BLMs, composed of mixtures of egg phosphatidylcholine (egg PC) and dipalmitoylphosphatidic acid (DPPA), were supported on ultrafiltration membranes (glass microfibre or polycarbonate filters) which were found to enhance their stability for flow experiments. The proteins (enzymes, antibodies) were incorporated into a floating lipid matrix at an air-electrolyte interface, and then a casting procedure was used to deliver the lipid onto the filter supports for BLM formation. Injections of the analyte were made into flowing streams of the carrier electrolyte solution and a current transient signal was obtained with a magnitude related to the analyte concentration. Substrates of hydrolytic enzyme reactions (acetylcholine, urea and penicillin) could be determined at the micromolar level with a maximum rate of 220 samples/h, whereas antigens (thyroxin) and triazine herbicides (simazine, atrazine and propazine) could be monitored at the nanomolar level in less than 2 min. The time of appearance of the transient response obtained for herbicides was increased to the order of simazine, atrazine and propazine which has permitted analysis of these triazines in mixtures. PMID:18924789

Laboratory degradation studies of 14C-atrazine and -isoproturon in soil from sugarcane cultivated fields under Kenyan tropical conditions.

PubMed

Getenga, Z M; Dörfler, U; Schroll, R

2009-06-01

A study to compare the degradation rates of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diammine) and isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in soils from sugarcane fields with different practices of herbicides application was carried out. (14)C-atrazine was poorly mineralized to (14)CO(2) (1.10% +/- 0.22%) after 139 days of incubation in soil without previous exposure to atrazine. In the same soil also with no previous isoproturon exposure isoproturon was mineralized to (14)CO(2) by 7.70% +/- 0.94%. Atrazine mineralization after 98 days was 13.4% +/- 0.30% in soil which discontinued the use of atrazine in 1997 while it was 89.9% +/- 1.23% in soil in which atrazine is currently being used. The isoproturon mineralization values were 7.24% +/- 0.85% and 22.97% +/- 0.96% in soil which discontinued atrazine and soil currently using atrazine, respectively.

Involvement of ERK1/2 signaling pathway in atrazine action on FSH-stimulated LHR and CYP19A1 expression in rat granulosa cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fa, Svetlana; Pogrmic-Majkic, Kristina; Samardzija, Dragana

Worldwide used herbicide atrazine is linked to reproductive dysfunction in females. In this study, we investigated the effects and the mechanism of atrazine action in the ovary using a primary culture of immature granulosa cells. In granulosa cells, follicle-stimulating hormone (FSH) activates both cyclic adenosine monophosphate (cAMP) and extracellular-regulated kinase 1/2 (ERK1/2) cascades, with cAMP pathway being more important for luteinizing hormone receptor (LHR) and aromatase (CYP19A1) mRNA expression. We report that 48 h after atrazine exposure the FSH-stimulated LHR and CYP19A1 mRNA expression and estradiol synthesis were decreased, with LHR mRNA being more sensitive to atrazine than CYP19A1 mRNA.more » Inadequate acquisition of LHR in the FSH-stimulated and atrazine-exposed granulosa cells renders human chorionic gonadotropin (hCG) ineffective to stimulate amphiregulin (Areg), epiregulin (Ereg), and progesterone receptor (Pgr) mRNA expression, suggesting anti-ovulatory effect of atrazine. To dissect the signaling cascade involved in atrazine action in granulosa cells, we used U0126, a pharmacological inhibitor of ERK1/2. U0126 prevents atrazine-induced decrease in LHR and CYP19A1 mRNA levels and estradiol production in the FSH-stimulated granulosa cells. ERK1/2 inactivation restores the ability of hCG to induce expression of the ovulatory genes in atrazine-exposed granulosa cells. Cell-based ELISA assay revealed that atrazine does not change the FSH-stimulated ERK1/2 phosphorylation in granulosa cells. The results from this study reveal that atrazine does not affect but requires ERK1/2 phosphorylation to cause decrease in the FSH-induced LHR and CYP19A1 mRNA levels and estradiol production in immature granulosa cells, thus compromising ovulation and female fertility. - Highlights: • Atrazine inhibits estradiol production in FSH-stimulated granulosa cells. • Atrazine inhibits LHR and Cyp19a1 mRNA expression in FSH-stimulated granulosa cells. • Atrazine prevents hCG-induced expression of the ovulatory genes. • ERK1/2 activation is required for atrazine action in granulosa cells. • Atrazine does not interfere with FSH-stimulated ERK1/2 phosphorylation.« less

Effects of atrazine on embryos, larvae, and adults of anuran amphibians.

PubMed

Allran, J W; Karasov, W H

2001-04-01

We examined the effects of atrazine (0-20 mg/L) on embryos, larvae, and adult anuran amphibian species in the laboratory. Atrazine treatments did not affect hatchability of embryos or 96-h posthatch mortality of larvae of Rana pipiens, Rana sylvatica, or Bufo americanus. Furthermore, atrazine had no effect on swimming speed (measured for R. pipiens only). However, there was a dose-dependent increase in deformed larvae of all three species with increasing atrazine concentration. In adult R. pipiens, atrazine increased buccal and thoracic ventilation, indicating respiratory distress. However, because atrazine had no affect on hemoglobin, this respiratory distress was probably not indicative of reduced oxygen-carrying capacity of the blood. Frogs exposed to the highest atrazine concentration stopped eating immediately after treatment began and did not eat during the 14-d experiment. However, no decreases in mass were measured even for frogs that were not eating, probably because of compensatory fluid gain from edema. Atrazine concentrations found to be deleterious to amphibian embryos and adults are considerably higher than concentrations currently found in surface waters in North America. Therefore, direct toxicity of atrazine is probably not a significant factor in recent amphibian declines.

Atrazine reduces reproduction in Japanese medaka (Oryzias latipes)

USGS Publications Warehouse

Papoulias, Diana M.; Tillitt, Donald E.; Talykina, Melaniya G.; Whyte, Jeffrey J.; Richter, Catherine A.

2014-01-01

Atrazine is an effective broadleaf herbicide and the second most heavily used herbicide in the United States. Effects along the hypothalamus–pituitary–gonad axis in a number of vertebrate taxa have been demonstrated. Seasonally elevated concentrations of atrazine in surface waters may adversely affect fishes, but only a few studies have examined reproductive effects of this chemical. The present study was designed to evaluate a population endpoint (egg production) in conjunction with histological (reproductive stage, gonad pathology) and biochemical (aromatase activity, sex hormone production) phenotypes associated with atrazine exposure in Japanese medaka. Adult virgin breeding groups of one male and four females were exposed to nominal concentrations of 0, 0.5, 5.0, and 50 μg/L (0, 2.3, 23.2, 231 nM) of atrazine in a flow-through diluter for 14 or 38 days. Total egg production was lower (36–42%) in all atrazine-exposed groups as compared to the controls. The decreases in cumulative egg production of atrazine-treated fish were significant by exposure day 24. Reductions in total egg production in atrazine treatment groups were most attributable to a reduced number of eggs ovulated by females in atrazine-treated tanks. Additionally, males exposed to atrazine had a greater number of abnormal germ cells. There was no effect of atrazine on gonadosomatic index, aromatase protein, or whole body 17 β-estradiol or testosterone. Our results suggest that atrazine reduces egg production through alteration of final maturation of oocytes. The reduced egg production observed in this study was very similar to our previously reported results for fathead minnow. This study provides further information with which to evaluate atrazine's risk to fish populations.

Soil mesocosm studies on atrazine bioremediation.

PubMed

Sagarkar, Sneha; Nousiainen, Aura; Shaligram, Shraddha; Björklöf, Katarina; Lindström, Kristina; Jørgensen, Kirsten S; Kapley, Atya

2014-06-15

Accumulation of pesticides in the environment causes serious issues of contamination and toxicity. Bioremediation is an ecologically sound method to manage soil pollution, but the bottleneck here, is the successful scale-up of lab-scale experiments to field applications. This study demonstrates pilot-scale bioremediation in tropical soil using atrazine as model pollutant. Mimicking field conditions, three different bioremediation strategies for atrazine degradation were explored. 100 kg soil mesocosms were set-up, with or without atrazine application history. Natural attenuation and enhanced bioremediation were tested, where augmentation with an atrazine degrading consortium demonstrated best pollutant removal. 90% atrazine degradation was observed in six days in soil previously exposed to atrazine, while soil without history of atrazine use, needed 15 days to remove the same amount of amended atrazine. The bacterial consortium comprised of 3 novel bacterial strains with different genetic atrazine degrading potential. The progress of bioremediation was monitored by measuring the levels of atrazine and its intermediate, cyanuric acid. Genes from the atrazine degradation pathway, namely, atzA, atzB, atzD, trzN and trzD were quantified in all mesocosms for 60 days. The highest abundance of all target genes was observed on the 6th day of treatment. trzD was observed in the bioaugmented mesocosms only. The bacterial community profile in all mesocosms was monitored by LH-PCR over a period of two months. Results indicate that the communities changed rapidly after inoculation, but there was no drastic change in microbial community profile after 1 month. Results indicated that efficient bioremediation of atrazine using a microbial consortium could be successfully up-scaled to pilot scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study of the Bioremediation of Atrazine under Variable Carbon and Nitrogen Sources by Mixed Bacterial Consortium Isolated from Corn Field Soil in Fars Province of Iran

PubMed Central

Nasseri, Simin; Hashemi, Hassan

2013-01-01

Atrazine herbicide that is widely used in corn production is frequently detected in water resources. The main objectives of this research were focused on assessing the effects of carbon and nitrogen sources on atrazine biodegradation by mixed bacterial consortium and by evaluating the feasibility of using mixed bacterial consortium in soil culture. Shiraz corn field soil with a long history of atrazine application has been explored for their potential of atrazine biodegradation. The influence of different carbon compounds and the effect of nitrogen sources and a different pH (5.5–8.5) on atrazine removal efficiency by mixed bacterial consortium in liquid culture were investigated. Sodium citrate and sucrose had the highest atrazine biodegradation rate (87.22%) among different carbon sources. Atrazine biodegradation rate decreased more quickly by the addition of urea (26.76%) compared to ammonium nitrate. Based on the data obtained in this study, pH of 7.0 is optimum for atrazine biodegradation. After 30 days of incubation, the percent of atrazine reduction rates were significantly enhanced in the inoculated soils (60.5%) as compared to uninoculated control soils (12%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with mixed bacterial consortium may enhance the rate of atrazine degradation in a highly polluted soil. PMID:23533452

Collaborative Simulation Grid: Multiscale Quantum-Mechanical/Classical Atomistic Simulations on Distributed PC Clusters in the US and Japan

NASA Technical Reports Server (NTRS)

Kikuchi, Hideaki; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya; Iyetomi, Hiroshi; Ogata, Shuji; Kouno, Takahisa; Shimojo, Fuyuki; Tsuruta, Kanji; Saini, Subhash;

Atrazine contamination in agricultural soils from the Yangtze River Delta of China and associated health risks.

PubMed

Sun, J T; Pan, L L; Zhan, Yu; Tsang, Daniel C W; Zhu, L Z; Li, X D

2017-04-01

Atrazine is one of the most widely applied and persistent herbicides in the world. In view of limited information on the regional contamination of atrazine in soils in China, this study investigated the spatial distribution and environmental impacts of atrazine in agricultural soils collected from the Yangtze River Delta (YRD) as an illustrative analysis of rapidly developing regions in the country. The results showed that the concentrations of atrazine in the YRD agricultural soils ranged from <1.0 to 113 ng/g dry weight, with a mean of 5.7 ng/g, and a detection rate of 57.7 % in soils. Pesticide factory might be a major source for the elevated levels of atrazine in Zhejiang Province. The contamination of atrazine was closely associated with land use types. The concentrations and detection rates of atrazine were higher in corn fields and mulberry fields than in rice paddy fields. There was no significant difference in compositions of soil microbial phospholipids fatty acids among the areas with different atrazine levels. Positive relationship (R = 0.417, p < 0.05, n = 30) was observed between atrazine and total microbial biomass. However, other factors, such as soil type and land management practice, might have stronger influences on soil microbial communities. Human health risks via exposure to atrazine in soils were estimated according to the methods recommended by the US EPA. Atrazine by itself in all the soil samples imposed very low carcinogenic risks (<10 -6 ) and minimal non-cancer risks (hazard index <1) to adults and children.

Effect of atrazine on potential denitrification in aquifer sediments

USGS Publications Warehouse

Bradley, P.M.; Chapelle, F.H.; Jagucki, M.L.; McMahon, P.B.

1994-01-01

Agriculturaf use of fertilizers and herbicides has often resulted in nitrate and atrazine contamination of the shallow aquifers that underlay cultivated fields. In several cases, the concentrations of atrazine and nitrate dissolved in ground water are positively correlated (Spalding ef al., 1979; Chen and Druliner, 1987; Spalding et al., 1989). Because simultaneous application of nitrate fertilizers and the herbicide, atrazine, is common, the co-occurrence of these contaminants in ground water is not entirely unexpected. However, the possibility also exists that this co-occurrence may ret&t interactions of atrazine with nitrate in the subsurface environment. R&ton and Cervelh (1980), McElhannon ei al. (1984) and Mills (1984) have reported that atrazine inhibits denitrification in‘soil’lf this i‘s indeed the case, atrazine contamination may contribute to nitrate preservation and accumulation in anaerobic aquifers by inhibiting denitrification, the principal mechanism for nitrate removal in anaerobic systems. Huwever, the effect of atrazine on the rate of denit~ficat~on in soils remains controversial, because atrazine has been reported variously to enhance denitrification (Cervelli and Ralston, 1983) or to have no effect on denitrification in soils (Bollag and Henninger, 1976; Yeomans and Bremner, IQ85, 1987). Moreover, the effect of dissolved atrazine concentrations on the rate of denitrification in aquifer sediments has not been reported. Our purpose was to determine the elects of dissolved atrazine concentrations on potential rates ofdenitri~~t~on in aquifer sediments from two different agricultural areas to evaluate the hypothesis that, by inhibiting denitrification, atrazine contributes to nitrate preservation in anaerobic aquifer systems.

Extractable atrazine and its metabolites in agricultural soils from the temperate humid zone.

PubMed

Mahía, J; Martín, A; Díaz-Raviña, M

2008-04-01

Extractable atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) were evaluated in agricultural soils from the temperate humid zone (Galicia, NW Spain) under laboratory conditions. The experiment was performed with five soils with different properties (organic C, soil texture and atrazine application history), both unamended and treated with atrazine at field application rate. Measurements of the atrazine compounds were made at different time intervals (1, 3, 6, 9 and 12 weeks) during a 3-month incubation period. Results showed that only hydroxyatrazine was detected in the extractable fraction of the unamended soils, with values remaining relatively constant throughout the incubation period. Atrazine addition notably increased the concentration of the parent compound and its degradation products; deisopropylatrazine and hydroxyatrazine were the main metabolites detected in the extractable fraction of the treated soils, whereas deethylatrazine was not detected. After 7 days incubation, values of total extractable residues, expressed as percentage of initially added atrazine, ranged from 75 to 86% (25-68% of atrazine, 7-11% of hydroxyatrazine and 9-57% of deisopropylatrazine). The values decreased rapidly during the first 3 weeks of incubation, showing values of 2-8% in soils with higher atrazine application and from 28 to 30% in soils with lower application history. At the end of the incubation, 2-8% of total extractable residues were still detected (0-4% of atrazine, 2-3% of hydroxyatrazine and 0-2% of deisopropylatrazine), indicating a residual effect of atrazine addition. These variations in the extractable fraction indicated that most added atrazine was rapidly degraded, especially in soils with higher application history.

Magnetic bionanoparticles of Penicillium sp. yz11-22N2 doped with Fe3O4 and encapsulated within PVA-SA gel beads for atrazine removal.

PubMed

Yu, Jiaping; He, Huijun; Yang, William L; Yang, Chunping; Zeng, Guangming; Wu, Xin

2018-07-01

A novel magnetic bionanomaterial, Penicillium sp. yz11-22N2 doped with nano Fe 3 O 4 entrapped in polyvinyl alcohol-sodium alginate gel beads (PFEPS), was successfully synthesized. The factors including nutrient substance, temperature, pH, initial concentrations of atrazine and rotational speeds were presented and discussed in detail. Results showed that the highest removal efficiency of atrazine by PFEPS was 91.2% at 8.00 mg/L atrazine. The maximum removal capacity for atrazine was 7.94 mg/g. Meanwhile, it has been found that most of atrazine were removed by metabolism and degradation of Penicillium sp. yz11-22N2, which could use atrazine as the sole source of either carbon or nitrogen. Degradation kinetics of atrazine conformed to first-order kinetics model. The intermediates indicated that the possible pathway for atrazine degradation by PFEPS mainly included hydrolysis dechlorination, dealkylation, side-chain oxidation and ring-opening. Copyright © 2018 Elsevier Ltd. All rights reserved.

Atrazine and its metabolites degradation in mineral salts medium and soil using an enrichment culture.

PubMed

Kumar, Anup; Singh, Neera

2016-03-01

An atrazine-degrading enrichment culture was used to study degradation of atrazine metabolites viz. hydroxyatrazine, deethylatrazine, and deisopropylatrazine in mineral salts medium. Results suggested that the enrichment culture was able to degrade only hydroxyatrazine, and it was used as the sole source of carbon and nitrogen. Hydroxyatrazine degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as the additional sources of carbon and nitrogen, respectively. The enrichment culture could degrade high concentrations of atrazine (up to 110 μg/mL) in mineral salts medium, and neutral pH was optimum for atrazine degradation. Further, except in an acidic soil, enrichment culture was able to degrade atrazine in three soil types having different physico-chemical properties. Raising the pH of acidic soil to neutral or alkaline enabled the enrichment culture to degrade atrazine suggesting that acidic pH inhibited atrazine-degrading ability. The study suggested that the enrichment culture can be successfully utilized to achieve complete degradation of atrazine and its persistent metabolite hydroxyatrazine in the contaminated soil and water.

2004 National Atrazine Occurrence Monitoring Program using the Abraxis ELISA method.

PubMed

Graziano, Nicole; McGuire, Michael J; Roberson, Alan; Adams, Craig; Jiang, Hua; Blute, Nicole

2006-02-15

The goal of this project was to gain a better understanding of atrazine occurrence in the United States by surveying drinking water utilities' sources and finished water for atrazine on a weekly basis for seven months. Atrazine is a contaminant of interest because the United States Environmental Protection Agency (USEPA) has found short-term atrazine exposure above the drinking water maximum contaminant level (MCL) to potentially cause heart, lung, and kidney congestion, low blood pressure, muscle spasms, weight loss, and damage to the adrenal glands. Long-term exposure to atrazine concentrations above the drinking water MCL has been linked to weight loss, cardiovascular damage, retinal and muscle degeneration, and cancer. This survey effort improved upon previously conducted atrazine surveys through intensive, high frequency sampling (participating plants sampled their raw and finished water on a weekly basis for approximately seven months). Such an intensive effort allowed the authors to gain a better understanding of short-term atrazine occurrence and its variability in drinking water sources. This information can benefit the drinking water industry by facilitating (1) better atrazine occurrence management (i.e., awareness when plants may be more susceptible to atrazine), (2) more efficient atrazine control (e.g., effective treatment alternatives and more effective response to atrazine occurrence), and (3) treatment cost reduction (e.g., efficient atrazine control can result in substantial cost savings). Forty-seven drinking watertreatment plants located primarily in the Midwestern United States participated in the survey and sampled their raw and finished water on a weekly basis from March through October. Samples were analyzed using the Abraxis enzyme-linked immunosorbent assay (ELISA) test kit. Confirmation samples for quality assurance/quality control (QA/QC) purposes were analyzed using solid-phase extraction (SPE) followed by gas chromatography mass spectrophotometry (GC/MS). Several important conclusions can be drawn from this study including (1) surface waters were confirmed to be more vulnerable to atrazine contamination than groundwater sources, (2) peak atrazine concentrations corresponded well to precipitation/runoff events, and (3) atrazine occurrence tended to be uniform geographically when compared by river drainage basins. In addition, this project confirmed that the Abraxis atrazine ELISA test kit tended to have a positive bias (i.e., the measured ELISA concentration was higher than the actual concentration) in most measured samples. Finished samples tended to have more of a positive bias than raw water samples. Therefore, this bias may limit the effectiveness for ELISA for regulatory monitoring. There are many other applications for ELISA, however, including frequent monitoring for early detections of atrazine concentration changes that might trigger conventional analysis by GC/MS or be used for activated carbon dosing or other treatment operating controls.

Contribution of hydroxylated atrazine degradation products to the total atrazine load in midwestern streams

USGS Publications Warehouse

Lerch, R.N.; Blanchard, P.E.; Thurman, E.M.

1998-01-01

The contribution of hydroxylated atrazine degradation products (HADPs) to the total atrazine load (i.e., atrazine plus stable metabolites)in streams needs to be determined in order to fully assess the impact of atrazine contamination on stream ecosystems and human health. The objectives of this study were (1) to determine the contribution of HADPs to the total atrazine load in streams of nine midwestern states and (2) to discuss the mechanisms controlling the concentrations of HADPs in streams. Stream samples were collected from 95 streams in northern Missouri at preplant and postplant of 1994 and 1995, and an additional 46 streams were sampled in eight midwestern states at postplant of 1995. Samples were analyzed for atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and three HADPs. Overall, HADP prevalence (i.e., frequency of detection) ranged from 87 to 100% for hydroxyatrazine (HA), 0 to 58% for deethylhydroxyatrazine (DEHA), and 0% for deisopropylhydroxyatrazine (DIHA) with method detection limits of 0.04-0.10 ??g L-1. Atrazine metabolites accounted for nearly 60% of the atrazine load in northern Missouri streams at preplant, with HA the predominant metabolite present. Data presented in this study and a continuous monitoring study are used to support the hypothesis that a combination of desorption from stream sediments and dissolved-phase transport control HADP concentrations in streams.The contribution of hydroxylated atrazine degradation products (HADPs) to the total atrazine load (i.e., atrazine plus stable metabolites) in streams needs to be determined in order to fully assess the impact of atrazine contamination on stream ecosystems and human health. The objectives of this study were (1) to determine the contribution of HADPs to the total atrazine load in streams of nine midwestern states and (2) to discuss the mechanisms controlling the concentrations of HADPs in streams. Stream samples were collected from 95 streams in northern Missouri at preplant and postplant of 1994 and 1995, and an additional 46 streams were sampled in eight midwestern states at postplant of 1995. Samples were analyzed for atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and three HADPs. Overall, HADP prevalence (i.e., frequency of detection) ranged from 87 to 100% for hydroxyatrazine (HA), 0 to 58% for deethylhydroxyatrazine (DEHA), and 0% for deisopropylhydroxyatrazine (DIHA) with method detection limits of 0.04-0.10 ??g L-1. Atrazine metabolites accounted for nearly 60% of the atrazine load in northern Missouri streams at preplant, with HA the predominant metabolite present. Data presented in this study and a continuous monitoring study are used to support the hypothesis that a combination of desorption from stream sediments and dissolved-phase transport control HADP concentrations in streams.

Transgenic tobacco plants expressing atzA exhibit resistance and strong ability to degrade atrazine.

PubMed

Wang, Huizhuan; Chen, Xiwen; Xing, Xuguang; Hao, Xiaohua; Chen, Defu

2010-12-01

Atrazine chlorohydrolase (AtzA) catalyzes hydrolytic dechlorination and can be used in detoxification of atrazine, a herbicide widely employed in the control of broadleaf weeds. In this study, to investigate the potential use of transgenic tobacco plants for phytoremediation of atrazine, atzA genes from Pseudomonas sp. strain ADP and Arthrobacter strain AD1 were transferred into tobacco. Three and four transgenic lines, expressing atzA-ADP and atzA-AD1, respectively, were produced by Agrobacterium-mediated transformation. Molecular characterization including PCR, RT-PCR and Southern blot revealed that atzA was inserted into the tobacco genome and stably inherited by and expressed in the progenies. Seeds of the T(1) transgenic lines had a higher germination percentage and longer roots than the untransformed plants in the presence of 40-150 mg/l atrazine. The T(2) transgenic lines grew taller, gained more dry biomass, and had higher total chlorophyll content than the untransformed plants after growing in soil containing 1 or 2 mg/kg atrazine for 90 days. No atrazine residue remained in the soil in which the T(2) transgenic lines were grown (except 401), while, in the case of the untransformed plants, 0.91 mg (81.3%) and 1.66 mg (74.1%) of the atrazine still remained in the soil containing 1 and 2 mg/kg of atrazine, respectively, indicating that the transgenic lines could degrade atrazine effectively. The transgenic tobacco lines developed could be useful for phytoremediation of atrazine-contaminated soil and water.

Assessment of bioavailability of soil-sorbed atrazine.

PubMed

Park, Jeong-Hun; Feng, Yucheng; Ji, Pingsheng; Voice, Thomas C; Boyd, Stephen A

2003-06-01

Bioavailability of pesticides sorbed to soils is an important determinant of their environmental fate and impact. Mineralization of sorbed atrazine was studied in soil and clay slurries, and a desorption-biodegradation-mineralization (DBM) model was developed to quantitatively evaluate the bioavailability of sorbed atrazine. Three atrazine-degrading bacteria that utilized atrazine as a sole N source (Pseudomonas sp. strain ADP, Agrobacterium radiobacter strain J14a, and Ralstonia sp. strain M91-3) were used in the bioavailability assays. Assays involved establishing sorption equilibrium in sterile soil slurries, inoculating the system with organisms, and measuring the CO(2) production over time. Sorption and desorption isotherm analyses were performed to evaluate distribution coefficients and desorption parameters, which consisted of three desorption site fractions and desorption rate coefficients. Atrazine sorption isotherms were linear for mineral and organic soils but displayed some nonlinearity for K-saturated montmorillonite. The desorption profiles were well described by the three-site desorption model. In many instances, the mineralization of atrazine was accurately predicted by the DBM model, which accounts for the extents and rates of sorption/desorption processes and assumes biodegradation of liquid-phase, but not sorbed, atrazine. However, for the Houghton muck soil, which manifested the highest sorbed atrazine concentrations, enhanced mineralization rates, i.e., greater than those expected on the basis of aqueous-phase atrazine concentration, were observed. Even the assumption of instantaneous desorption could not account for the elevated rates. A plausible explanation for enhanced bioavailability is that bacteria access the localized regions where atrazine is sorbed and that the concentrations found support higher mineralization rates than predicted on the basis of aqueous-phase concentrations. Characteristics of high sorbed-phase concentration, chemotaxis, and attachment of cells to soil particles seem to contribute to the bioavailability of soil-sorbed atrazine.

Assessment of Bioavailability of Soil-Sorbed Atrazine

PubMed Central

Park, Jeong-Hun; Feng, Yucheng; Ji, Pingsheng; Voice, Thomas C.; Boyd, Stephen A.

2003-01-01

Bioavailability of pesticides sorbed to soils is an important determinant of their environmental fate and impact. Mineralization of sorbed atrazine was studied in soil and clay slurries, and a desorption-biodegradation-mineralization (DBM) model was developed to quantitatively evaluate the bioavailability of sorbed atrazine. Three atrazine-degrading bacteria that utilized atrazine as a sole N source (Pseudomonas sp. strain ADP, Agrobacterium radiobacter strain J14a, and Ralstonia sp. strain M91-3) were used in the bioavailability assays. Assays involved establishing sorption equilibrium in sterile soil slurries, inoculating the system with organisms, and measuring the CO2 production over time. Sorption and desorption isotherm analyses were performed to evaluate distribution coefficients and desorption parameters, which consisted of three desorption site fractions and desorption rate coefficients. Atrazine sorption isotherms were linear for mineral and organic soils but displayed some nonlinearity for K-saturated montmorillonite. The desorption profiles were well described by the three-site desorption model. In many instances, the mineralization of atrazine was accurately predicted by the DBM model, which accounts for the extents and rates of sorption/desorption processes and assumes biodegradation of liquid-phase, but not sorbed, atrazine. However, for the Houghton muck soil, which manifested the highest sorbed atrazine concentrations, enhanced mineralization rates, i.e., greater than those expected on the basis of aqueous-phase atrazine concentration, were observed. Even the assumption of instantaneous desorption could not account for the elevated rates. A plausible explanation for enhanced bioavailability is that bacteria access the localized regions where atrazine is sorbed and that the concentrations found support higher mineralization rates than predicted on the basis of aqueous-phase concentrations. Characteristics of high sorbed-phase concentration, chemotaxis, and attachment of cells to soil particles seem to contribute to the bioavailability of soil-sorbed atrazine. PMID:12788728

Evaluation of the side effects of poly(epsilon-caprolactone) nanocapsules containing atrazine toward maize plants.

PubMed

Oliveira, Halley C; Stolf-Moreira, Renata; Martinez, Cláudia B R; Sousa, Gustavo F M; Grillo, Renato; de Jesus, Marcelo B; Fraceto, Leonardo F

2015-01-01

Poly(epsilon-caprolactone) (PCL) nanocapsules have been used as a carrier system for the herbicide atrazine, which is commonly applied to maize. We demonstrated previously that these atrazine containing polymeric nanocapsules were 10-fold more effective in the control of mustard plants (a target species), as compared to a commercial atrazine formulation. Since atrazine can have adverse effects on non-target crops, here we analyzed the effect of encapsulated atrazine on growth, physiological and oxidative stress parameters of soil-grown maize plants (Zea mays L.). One day after the post-emergence treatment with PCL nanocapsules containing atrazine (1 mg mL(-1)), maize plants presented 15 and 21% decreases in maximum quantum yield of photosystem II (PSII) and in net CO2 assimilation rate, respectively, as compared to water-sprayed plants. The same treatment led to a 1.8-fold increase in leaf lipid peroxidation in comparison with control plants. However, all of these parameters were unaffected 4 and 8 days after the application of encapsulated atrazine. These results suggested that the negative effects of atrazine were transient, probably due to the ability of maize plants to detoxify the herbicide. When encapsulated atrazine was applied at a 10-fold lower concentration (0.1 mg mL(-1)), a dosage that is still effective for weed control, no effects were detected even shortly after application. Regardless of the herbicide concentration, neither pre- nor post-emergence treatment with the PCL nanocapsules carrying atrazine resulted in the development of any macroscopic symptoms in maize leaves, and there were no impacts on shoot growth. Additionally, no effects were observed when plants were sprayed with PCL nanocapsules without atrazine. Overall, these results suggested that the use of PCL nanocapsules containing atrazine did not lead to persistent side effects in maize plants, and that the technique could offer a safe tool for weed control without affecting crop growth.

Evaluation of the side effects of poly(epsilon-caprolactone) nanocapsules containing atrazine towards maize plants

NASA Astrophysics Data System (ADS)

Oliveira, Halley; Stolf-Moreira, Renata; Martinez, Cláudia; Sousa, Gustavo; Grillo, Renato; de Jesus, Marcelo; Fraceto, Leonardo

2015-10-01

Poly(epsilon-caprolactone) (PCL) nanocapsules have been used as a carrier system for the herbicide atrazine, which is commonly applied to maize. We demonstrated previously that these atrazine containing polymeric nanocapsules were ten-fold more effective in the control of mustard plants (a target species), as compared to a commercial atrazine formulation. Since atrazine can have adverse effects on non-target crops, here we analyzed the effect of encapsulated atrazine on growth, physiological and oxidative stress parameters of soil-grown maize plants (Zea mays L.). One day after the post-emergence treatment with PCL nanocapsules containing atrazine (1 mg mL-1), maize plants presented 15 and 21 % decreases in maximum quantum yield of photosystem II and in net CO2 assimilation rate, respectively, as compared to water-sprayed plants. The same treatment led to a 1.8-fold increase in leaf lipid peroxidation in comparison with control plants. However, all of these parameters were unaffected four and eight days after the application of encapsulated atrazine. These results suggested that the negative effects of atrazine were transient, probably due to the ability of maize plants to detoxify the herbicide. When encapsulated atrazine was applied at a ten-fold lower concentration (0.1 mg mL-1), a dosage that is still effective for weed control, no effects were detected even shortly after application. Regardless of the herbicide concentration, neither pre- nor post-emergence treatment with the PCL nanocapsules carrying atrazine resulted in the development of any macroscopic symptoms in maize leaves, and there were no impacts on shoot growth. Additionally, no effects were observed when plants were sprayed with PCL nanocapsules without atrazine. Overall, these results suggested that the use of PCL nanocapsules containing atrazine did not lead to persistent side effects in maize plants, and that the technique could offer a safe tool for weed control without affecting crop growth.

Bioavailability of organoclay formulations of atrazine in soil.

PubMed

Trigo, Carmen; Koskinen, William C; Celis, Rafael; Sadowsky, Michael J; Hermosín, María C; Cornejo, Juan

2010-11-24

Pesticide formulations based on organoclays have been proposed to prolong the efficacy and reduce the environmental impact of pesticides in soil. This research addressed the question of whether atrazine in organoclay-based formulations is irreversibly sorbed or is bioavailable for bacterial degradation in soil. Different cations of l-carnitine (CAR), tyramine (TYRAM), hexadimethrine (HEXADIM), phenyltrimethylammonium (PTMA), hexadecyltrimethylammonium (HDTMA), and Fe(III) were incorporated into Na-rich Wyoming montmorillonite (SWy-2) and Ca-rich Arizona montmorillonite (SAz-1) at 100% of the cation exchange capacity (CEC) of the clays as a strategy to enhance the affinity of the clay minerals for atrazine. A Buse loam soil from Becker, MN, was treated with three organoclay-based formulations of 14C-atrazine or free herbicide and incubated for 2 weeks. To determine the bioavailability of 14C-atrazine, the soil was inoculated with Pseudomonas sp. strain ADP, which rapidly mineralizes atrazine. At day 0, and after a 2 week incubation, mineralization and the amount of 14C-atrazine residues distributed between the aqueous-extractable, methanol-extractable, and bound fractions in the soil were determined to characterize the availability of nonaged and aged atrazine residues. By the end of the 2 week incubation, the microorganisms had mineralized >80% of the initial readily available (water-extractable) and >70% of the less readily available (methanol-extractable) 14C-atrazine in the soil. Bound residues increased from <4% at day 0 to ∼17% after the 2 week incubation for both the formulated and free forms of atrazine. The results of these incubation experiments show that the bioavailabilities of atrazine were similar in the case of the organoclay formulations and as free atrazine. This indicated that whereas more atrazine was sorbed and less likely to be transported in soil, when formulated as organoclay complexes, it was ultimately accessible to degrading bacteria, so that the herbicide is likely to be naturally attenuated by soil microorganisms.

Probability of detecting atrazine/desethyl-atrazine and elevated concentrations of nitrate in ground water in Colorado

USGS Publications Warehouse

Rupert, Michael G.

2003-01-01

Draft Federal regulations may require that each State develop a State Pesticide Management Plan for the herbicides atrazine, alachlor, metolachlor, and simazine. Maps were developed that the State of Colorado could use to predict the probability of detecting atrazine and desethyl-atrazine (a breakdown product of atrazine) in ground water in Colorado. These maps can be incorporated into the State Pesticide Management Plan and can help provide a sound hydrogeologic basis for atrazine management in Colorado. Maps showing the probability of detecting elevated nitrite plus nitrate as nitrogen (nitrate) concentrations in ground water in Colorado also were developed because nitrate is a contaminant of concern in many areas of Colorado. Maps showing the probability of detecting atrazine and(or) desethyl-atrazine (atrazine/DEA) at or greater than concentrations of 0.1 microgram per liter and nitrate concentrations in ground water greater than 5 milligrams per liter were developed as follows: (1) Ground-water quality data were overlaid with anthropogenic and hydrogeologic data using a geographic information system to produce a data set in which each well had corresponding data on atrazine use, fertilizer use, geology, hydrogeomorphic regions, land cover, precipitation, soils, and well construction. These data then were downloaded to a statistical software package for analysis by logistic regression. (2) Relations were observed between ground-water quality and the percentage of land-cover categories within circular regions (buffers) around wells. Several buffer sizes were evaluated; the buffer size that provided the strongest relation was selected for use in the logistic regression models. (3) Relations between concentrations of atrazine/DEA and nitrate in ground water and atrazine use, fertilizer use, geology, hydrogeomorphic regions, land cover, precipitation, soils, and well-construction data were evaluated, and several preliminary multivariate models with various combinations of independent variables were constructed. (4) The multivariate models that best predicted the presence of atrazine/DEA and elevated concentrations of nitrate in ground water were selected. (5) The accuracy of the multivariate models was confirmed by validating the models with an independent set of ground-water quality data. (6) The multivariate models were entered into a geographic information system and the probability maps were constructed.

Uptake of C14-atrazine by prairie grasses in a phytoremediation setting.

PubMed

Khrunyk, Yuliya; Schiewer, Silke; Carstens, Keri L; Hu, Dingfei; Coats, Joel R

2017-02-01

Agrochemicals significantly contribute to environmental pollution. In the USA, atrazine is a widely used pesticide and commonly found in rivers, water systems, and rural wells. Phytoremediation can be a cost-effective means of removing pesticides from soil. The objective of this project was to investigate the ability of prairie grasses to remove atrazine. 14 C-labeled atrazine was added to sterilized sand and water/nutrient cultures, and the analysis was performed after 21 days. Switchgrass and big bluestem were promising species for phytoremediation, taking up about 40% of the applied [ 14 C] in liquid hydroponic cultures, and between 20% and 33% in sand cultures. Yellow Indiangrass showed low resistance to atrazine toxicity and low uptake of [ 14 C] atrazine in liquid hydroponic cultures. Atrazine degradation increased progressively from sand to roots and leaves. Most atrazine taken up by prairie grasses from sand culture was degraded to metabolites, which accounted for 60-80% of [ 14 C] detected in leaves. Deisopropylatrazine (DIA) was the main metabolite detected in sand and roots, whereas in leaves further metabolism took place, forming increased amounts of didealkylatrazine (DDA) and an unidentified metabolite. In conclusion, prairie grasses achieved high atrazine removal and degradation, showing a high potential for phytoremediation.

AERO2S - SUBSONIC AERODYNAMIC ANALYSIS OF WINGS WITH LEADING- AND TRAILING-EDGE FLAPS IN COMBINATION WITH CANARD OR HORIZONTAL TAIL SURFACES (IBM PC VERSION)

NASA Technical Reports Server (NTRS)

Carlson, H. W.

1994-01-01

This code was developed to aid design engineers in the selection and evaluation of aerodynamically efficient wing-canard and wing-horizontal-tail configurations that may employ simple hinged-flap systems. Rapid estimates of the longitudinal aerodynamic characteristics of conceptual airplane lifting surface arrangements are provided. The method is particularly well suited to configurations which, because of high speed flight requirements, must employ thin wings with highly swept leading edges. The code is applicable to wings with either sharp or rounded leading edges. The code provides theoretical pressure distributions over the wing, the canard or horizontal tail, and the deflected flap surfaces as well as estimates of the wing lift, drag, and pitching moments which account for attainable leading edge thrust and leading edge separation vortex forces. The wing planform information is specified by a series of leading edge and trailing edge breakpoints for a right hand wing panel. Up to 21 pairs of coordinates may be used to describe both the leading edge and the trailing edge. The code has been written to accommodate 2000 right hand panel elements, but can easily be modified to accommodate a larger or smaller number of elements depending on the capacity of the target computer platform. The code provides solutions for wing surfaces composed of all possible combinations of leading edge and trailing edge flap settings provided by the original deflection multipliers and by the flap deflection multipliers. Up to 25 pairs of leading edge and trailing edge flap deflection schedules may thus be treated simultaneously. The code also provides for an improved accounting of hinge-line singularities in determination of wing forces and moments. To determine lifting surface perturbation velocity distributions, the code provides for a maximum of 70 iterations. The program is constructed so that successive runs may be made with a given code entry. To make additional runs, it is necessary only to add an identification record and the namelist data that are to be changed from the previous run. This code was originally developed in 1989 in FORTRAN V on a CDC 6000 computer system, and was later ported to an MS-DOS environment. Both versions are available from COSMIC. There are only a few differences between the PC version (LAR-14458) and CDC version (LAR-14178) of AERO2S distributed by COSMIC. The CDC version has one main source code file while the PC version has two files which are easier to edit and compile on a PC. The PC version does not require a FORTRAN compiler which supports NAMELIST because a special INPUT subroutine has been added. The CDC version includes two MODIFY decks which can be used to improve the code and prevent the possibility of some infrequently occurring errors while PC-version users will have to make these code changes manually. The PC version includes an executable which was generated with the Ryan McFarland/FORTRAN compiler and requires 253K RAM and an 80x87 math co-processor. Using this executable, the sample case requires about four hours to execute on an 8MHz AT-class microcomputer with a co-processor. The source code conforms to the FORTRAN 77 standard except that it uses variables longer than six characters. With two minor modifications, the PC version should be portable to any computer with a FORTRAN compiler and sufficient memory. The CDC version of AERO2S is available in CDC NOS Internal format on a 9-track 1600 BPI magnetic tape. The PC version is available on a set of two 5.25 inch 360K MS-DOS format diskettes. IBM AT is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. CDC is a registered trademark of Control Data Corporation. NOS is a trademark of Control Data Corporation.

Effects of farming systems on ground-water quality at the management systems evaluation area near Princeton, Minnesota, 1991-95

USGS Publications Warehouse

Landon, M.K.; Delin, G.N.; Lamb, J.A.; Anderson, J.L.; Dowdy, R.H.

1998-01-01

The proportion of applied atrazine in ground water, detected as atrazine or its metabolites, ranged from 0 to about 1 percent with an average of 0.37 percent. The small proportion of applied atrazine detected in ground water indicates that atrazine was predominantly affected by processes occurring in the soil such as adsorption and degradation. Concentrations of atrazine plus metabolites were related to application rates.

Exogenous calcium induces tolerance to atrazine stress in Pennisetum seedlings and promotes photosynthetic activity, antioxidant enzymes and psbA gene transcripts.

PubMed

Erinle, Kehinde Olajide; Jiang, Zhao; Ma, Bingbing; Li, Jinmei; Chen, Yukun; Ur-Rehman, Khalil; Shahla, Andleeb; Zhang, Ying

2016-10-01

Calcium (Ca) has been reported to lessen oxidative damages in plants by upregulating the activities of antioxidant enzymes. However, atrazine mediated reactive oxygen species (ROS) reduction by Ca is limited. This study therefore investigated the effect of exogenously applied Ca on ROS, antioxidants activity and gene transcripts, the D1 protein (psbA gene), and chlorophyll contents in Pennisetum seedlings pre-treated with atrazine. Atrazine toxicity increased ROS production and enzyme activities (ascorbate peroxidase APX, peroxidase POD, Superoxide dismutase SOD, glutathione-S-transferase GST); but decreased antioxidants (APX, POD, and Cu/Zn SOD) and psbA gene transcripts. Atrazine also decreased the chlorophyll contents, but increased chlorophyll (a/b) ratio. Contrarily, Ca application to atrazine pre-treated seedlings lowered the harmful effects of atrazine by reducing ROS levels, but enhancing the accumulation of total chlorophyll contents. Ca-protected seedlings in the presence of atrazine manifested reduced APX and POD activity, whereas SOD and GST activity was further increased with Ca application. Antioxidant gene transcripts that were down-regulated by atrazine toxicity were up-regulated with the application of Ca. Calcium application also resulted in up-regulation of the D1 protein. In conclusion, ability of calcium to reverse atrazine-induced oxidative damage and calcium regulatory role on GST in Pennisetum was presented. Copyright © 2016 Elsevier Inc. All rights reserved.

Atrazine distribution measured in soil and leachate following infiltration conditions.

PubMed

Neurath, Susan K; Sadeghi, Ali M; Shirmohammadi, Adel; Isensee, Allan R; Torrents, Alba

2004-01-01

Atrazine transport through packed 10 cm soil columns representative of the 0-10 cm soil horizon was observed by measuring the atrazine recovery in the total leachate volume, and upper and lower soil layers following infiltration of 7.5 cm water using a mechanical vacuum extractor (MVE). Measured recoveries were analyzed to understand the influence of infiltration rate and delay time on atrazine transport and distribution in the column. Four time periods (0.28, 0.8, 1.8, and 5.5 h) representing very high to moderate infiltration rates (26.8, 9.4, 4.2, and 1.4 cm/h) were used. Replicate soil columns were tested immediately and following a 2-d delay after atrazine application. Results indicate atrazine recovery in leachate was independent of infiltration rate, but significantly lower for infiltration following a 2-d delay. Atrazine distribution in the 0-1 and 9-10 cm soil layers was affected by both infiltration rate and delay. These results are in contrast with previous field and laboratory studies that suggest that atrazine recovery in the leachate increases with increasing infiltration rate. It appears that the difference in atrazine recovery measured using the MVE and other leaching experiments using intact soil cores from this field site and the rain simulation equipment probably illustrates the effect of infiltrating water interacting with the atrazine present on the soil surface. This work suggests that atrazine mobilization from the soil surface is also dependent on interactions of the infiltrating water with the soil surface, in addition to the rate of infiltration through the surface soil.

Biodegradation of atrazine by three transgenic grasses and alfalfa expressing a modified bacterial atrazine chlorohydrolase gene

USDA-ARS?s Scientific Manuscript database

The widespread use of atrazine and other s-triazine herbicides to control weeds in agricultural production fields has impacted surface and ground water in the United States and elsewhere. We previously reported the cloning, sequencing, and expression of six genes involved in the atrazine biodegradat...

PITUITARY AND ADRENAL HORMONE RELEASE FOLLOWING in vitro EXPOSURE TO ATRAZINE AND ITS METABOLITE DEISOPROPYL-ATRAZINE (DIA)

EPA Science Inventory

Atrazine (ATR) is one of the most widely used herbicides in the United States, with current total annual use of approximately 76 million pounds of active ingredient. Previous work in our laboratory has shown that ATR and its metabolite deisopropyl-atrazine (DIA) induce a dose-dep...

[Degradation of the herbicide atrazine by the soil mycelial fungus INBI 2-26(-)--a producer of cellobiose dehydrogenase].

PubMed

Khromonygina, V V; Saltykova, A I; Vasil'chenko, L G; Kozlov, Iu P; Rabinovich, M L

2004-01-01

Nonsporulating mycelial fungi producing cellobiose dehydrogenase (CDH) and isolated from soils of South Vietnam with high residual content of dioxins are capable of growing on a solid medium in the presence of high atrazine concentrations (to 500 mg/l). At 20 and 50 mg/l atrazine, the area of fungal colonies was 1.5-1.2-fold larger, respectively, compared with control colonies of the same age, whereas development of the colonies at 500 mg/l atrazine was delayed by 5 days, compared with controls grown in the absence of atrazine. Surface cultivation of the fungus on a minimal medium with glucose as a sole source of carbon and energy decreased the initial concentration of atrazine (20 mg/l) 50 times in 40 days; in addition, no pronounced sorption of atrazine by mycelium was detected. This was paralleled by accumulation in the culture medium of extracellular CDH; atrazine increased the synthesis of this enzyme two- to threefold. Accumulation of beta-glucosidase (a mycelium-associated enzyme) and cellulases preceded the formation of CDH.

Effect of surfactants on sorption of atrazine by soil

NASA Astrophysics Data System (ADS)

Abu-Zreig, Majed; Rudra, R. P.; Dickinson, W. T.; Evans, L. J.

1999-03-01

This study investigates the effect of synthetic wastewater containing surfactants on the sorption of atrazine using an equilibrium batch technique. Laboratory experiments were conducted on three soils with two non-ionic (Rexol and Rexonic) surfactants and one anionic (Sulphonic) surfactant, specifically manufactured for the detergent industry. Four sets of experiments were conducted to examine the influence of surfactants on the equilibrium time of atrazine sorption, to explore the effect of surfactant concentration, pH and type of surfactant on the amount of atrazine sorbed and to determine sorption isotherms of atrazine in the presence of surfactants. The results indicate that the application of Sulphonic results in dramatic increase in the adsorption of atrazine on to soils, the increase being directly proportional to the concentration of the surfactant. Application of the Sulphonic surfactants with a concentration of 3000 mg/l can result in a significant increase in Kd values of atrazine for loam and sandy loam soils. On the other hand, the effect of non-ionic surfactants depends on their concentration. Generally, non-ionic surfactants can result in a slight increase in atrazine sorption at high concentration, an exception being Rexol on sandy loam soil. At low concentrations, non-ionic surfactants have shown a tendency to decrease atrazine sorption.

Adsorption-desorption behavior of atrazine on agricultural soils in China.

PubMed

Yue, Lin; Ge, ChengJun; Feng, Dan; Yu, Huamei; Deng, Hui; Fu, Bomin

2017-07-01

Adsorption and desorption are important processes that affect atrazine transport, transformation, and bioavailability in soils. In this study, the adsorption-desorption characteristics of atrazine in three soils (laterite, paddy soil and alluvial soil) were evaluated using the batch equilibrium method. The results showed that the kinetics of atrazine in soils was completed in two steps: a "fast" adsorption and a "slow" adsorption and could be well described by pseudo-second-order model. In addition, the adsorption equilibrium isotherms were nonlinear and were well fitted by Freundlich and Langmuir models. It was found that the adsorption data on laterite, and paddy soil were better fitted by the Freundlich model; as for alluvial soil, the Langmuir model described it better. The maximum atrazine sorption capacities ranked as follows: paddy soil>alluvial soil>laterite. Results of thermodynamic calculations indicated that atrazine adsorption on three tested soils was spontaneous and endothermic. The desorption data showed that negative hysteresis occurred. Furthermore, lower solution pH value was conducive to the adsorption of atrazine in soils. The atrazine adsorption in these three tested soils was controlled by physical adsorption, including partition and surface adsorption. At lower equilibrium concentration, the atrazine adsorption process in soils was dominated by surface adsorption; while with the increase of equilibrium concentration, partition was predominant. Copyright © 2016. Published by Elsevier B.V.

Atrazine removal from water by polycation-clay composites: effect of dissolved organic matter and comparison to activated carbon.

PubMed

Zadaka, Dikla; Nir, Shlomo; Radian, Adi; Mishael, Yael G

2009-02-01

Atrazine removal from water by two polycations pre-adsorbed on montmorillonite was studied. Batch experiments demonstrated that the most suitable composite poly (4-vinylpyridine-co-styrene)-montmorillonite (PVP-co-S90%-mont.) removed 90-99% of atrazine (0.5-28 ppm) within 20-40 min at 0.367% w/w. Calculations employing Langmuir's equation could simulate and predict the kinetics and final extents of atrazine adsorption. Column filter experiments (columns 20x1.6 cm) which included 2g of the PVP-co-S90%-mont. composite mixed with excess sand removed 93-96% of atrazine (800 ppb) for the first 800 pore volumes, whereas the same amount of granular activated carbon (GAC) removed 83-75%. In the presence of dissolved organic matter (DOM; 3.7 ppm) the efficiency of the GAC filter to remove atrazine decreased significantly (68-52% removal), whereas the corresponding efficiency of the PVP-co-S90%-mont. filter was only slightly influenced by DOM. At lower atrazine concentration (7 ppb) the PVP-co-S90%-mont. filter reduced even after 3000 pore volumes the emerging atrazine concentration below 3 ppb (USEPA standard). In the case of the GAC filter the emerging atrazine concentration was between 2.4 and 5.3 microg/L even for the first 100 pore volumes. Thus, the PVP-co-S90%-mont. composite is a new efficient material for the removal of atrazine from water.

Assessing the phytoremediation potential of crop and grass plants for atrazine-spiked soils.

PubMed

Sánchez, Virtudes; López-Bellido, Francisco Javier; Cañizares, Pablo; Rodríguez, Luis

2017-10-01

Pollution of soil and groundwater by atrazine has become an increasing environmental concern in the last decade. A phytoremediation test using plastic pots was conducted in order to assess the ability of several crops and grasses to remove atrazine from a soil of low permeability spiked with this herbicide. Four plant species were assessed for their ability to degrade or accumulate atrazine from soils: two grasses, i.e., ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea), and two crops, i.e., barley (Hordeum vulgare) and maize (Zea mays). Three different doses of atrazine were used for the contamination of the pots: 2, 5 and 10 mg kg -1 . 16 days after spiking, the initial amount of atrazine was reduced by 88.6-99.6% in planted pots, while a decrease of only 63.1-78.2% was found for the unplanted pots, thus showing the contribution of plants to soil decontamination. All the plant species were capable of accumulating atrazine and its N-dealkylated metabolites, i.e., deethylatrazine and deisopropylatrazine, in their tissues. Some toxic responses, such as biomass decreases and/or chlorosis, were observed in plants to a greater or lesser extent for initial soil doses of atrazine above 2 mg kg -1 . Maize was the plant species with the highest ability to accumulate atrazine derivatives, reaching up to 38.4% of the initial atrazine added to the soil. Rhizosphere degradation/mineralization by microorganisms or plant enzymes, together with degradation inside the plants, have been proposed as the mechanisms that contributed to a higher extent than plant accumulation to explain the removal of atrazine from soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distinct Detoxification Mechanisms Confer Resistance to Mesotrione and Atrazine in a Population of Waterhemp1[C][W][OPEN

PubMed Central

Ma, Rong; Kaundun, Shiv S.; Tranel, Patrick J.; Riggins, Chance W.; McGinness, Daniel L.; Hager, Aaron G.; Hawkes, Tim; McIndoe, Eddie; Riechers, Dean E.

2013-01-01

Previous research reported the first case of resistance to mesotrione and other 4-hydroxyphenylpyruvate dioxygenase (HPPD) herbicides in a waterhemp (Amaranthus tuberculatus) population designated MCR (for McLean County mesotrione- and atrazine-resistant). Herein, experiments were conducted to determine if target site or nontarget site mechanisms confer mesotrione resistance in MCR. Additionally, the basis for atrazine resistance was investigated in MCR and an atrazine-resistant but mesotrione-sensitive population (ACR for Adams County mesotrione-sensitive but atrazine-resistant). A standard sensitive population (WCS for Wayne County herbicide-sensitive) was also used for comparison. Mesotrione resistance was not due to an alteration in HPPD sequence, HPPD expression, or reduced herbicide absorption. Metabolism studies using whole plants and excised leaves revealed that the time for 50% of absorbed mesotrione to degrade in MCR was significantly shorter than in ACR and WCS, which correlated with previous phenotypic responses to mesotrione and the quantity of the metabolite 4-hydroxy-mesotrione in excised leaves. The cytochrome P450 monooxygenase inhibitors malathion and tetcyclacis significantly reduced mesotrione metabolism in MCR and corn (Zea mays) excised leaves but not in ACR. Furthermore, malathion increased mesotrione activity in MCR seedlings in greenhouse studies. These results indicate that enhanced oxidative metabolism contributes significantly to mesotrione resistance in MCR. Sequence analysis of atrazine-resistant (MCR and ACR) and atrazine-sensitive (WCS) waterhemp populations detected no differences in the psbA gene. The times for 50% of absorbed atrazine to degrade in corn, MCR, and ACR leaves were shorter than in WCS, and a polar metabolite of atrazine was detected in corn, MCR, and ACR that cochromatographed with a synthetic atrazine-glutathione conjugate. Thus, elevated rates of metabolism via distinct detoxification mechanisms contribute to mesotrione and atrazine resistance within the MCR population. PMID:23872617

Enhanced degradation and soil depth effects on the fate of atrazine and major metabolites in Colorado and Mississippi soils.

PubMed

Krutz, L Jason; Shaner, Dale L; Zablotowicz, Robert M

2010-01-01

The aim of this report is to inform modelers of the differences in atrazine fate between s-triazine-adapted and nonadapted soils as a function of depth in the profile and to recommend atrazine and metabolite input values for pesticide process submodules. The objectives of this study were to estimate the atrazine-mineralizing bacterial population, cumulative atrazine mineralization, atrazine persistence, and metabolite (desethylatrazine [DEA], deisopropylatrazine [DIA], and hydroxyatrazine [HA]) formation and degradation in Colorado and Mississippi s-triazine-adapted and nonadapted soils at three depths (0-5, 5-15, and 15-30 cm). Regardless of depth, the AMBP and cumulative atrazine mineralization was at least 3.8-fold higher in s-triazine-adapted than nonadapted soils. Atrazine half-life (T1/2) values pooled over nonadapted soils and depths approximated historic estimates (T1/2 = 60 d). Atrazine persistence in all depths of s-triazine-adapted soils was at least fourfold lower than that of the nonadapted soil. Atrazine metabolite concentrations were lower in s-triazine-adapted than in nonadapted soil by 35 d after incubation regardless of depth. Results indicate that (i) reasonable fate and transport modeling of atrazine will require identifying if soils are adapted to s-triazine herbicides. For example, our data confirm the 60-d T1/2 for atrazine in nonadapted soils, but a default input value of 6 d for atrazine is required for s-triazine adapted soils. (ii) Literature estimates for DEA, DIA, and HA T1/2 values in nonadapted soils are 52, 36, and 60 d, respectively, whereas our analysis indicates that reasonable T1/2 values for s-triazine-adapted soils are 10 d for DEA, 8 d for DIA, and 6 d for HA. (iii) An estimate for the relative distribution of DIA, DEA, and HA produced in nonadapted soils is 18, 72, and 10% of parent, respectively. In s-triazine-adapted soils, the values were 6, 23, and 71% for DIA, DEA, and HA, respectively. The effects of soil adaptation on metabolite distribution need to be confirmed in field experiments.

Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific phosphodiesterase-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kucka, Marek; Pogrmic-Majkic, Kristina; Fa, Svetlana

2012-11-15

Atrazine, one of the most commonly used herbicides worldwide, acts as an endocrine disruptor, but the mechanism of its action has not been characterized. In this study, we show that atrazine rapidly increases cAMP levels in cultured rat pituitary and testicular Leydig cells in a concentration-dependent manner, but less effectively than 3-isobutyl-1-methylxanthine, a competitive non-specific inhibitor of phosphodiesterases (PDEs). In forskolin (an activator of adenylyl cyclase)- and probenecid (an inhibitor of cyclic nucleotide transporters)-treated cells, but not in 3-isobutyl-1-methylxanthine-treated cells, atrazine further increased cAMP levels, indicating that inhibition of PDEs accounts for accumulation of cAMP. In contrast to cAMP, atrazinemore » did not alter cGMP levels, further indicating that it inhibits cAMP-specific PDEs. Atrazine-induced changes in cAMP levels were sufficient to stimulate prolactin release in pituitary cells and androgen production in Leydig cells, indicating that it acts as an endocrine disrupter both in cells that secrete by exocytosis of prestored hormones and in cells that secrete by de novo hormone synthesis. Rolipram abolished the stimulatory effect of atrazine on cAMP release in both cell types, suggesting that it acts as an inhibitor of PDE4s, isoforms whose mRNA transcripts dominate in pituitary and Leydig cells together with mRNA for PDE8A. In contrast, immortalized lacto-somatotrophs showed low expression of these mRNA transcripts and several fold higher cAMP levels compared to normal pituitary cells, and atrazine was unable to further increase cAMP levels. These results indicate that atrazine acts as a general endocrine disrupter by inhibiting cAMP-specific PDE4s. -- Highlights: ► Atrazine stimulates cAMP accumulation in pituitary and Leydig cells. ► Atrazine also stimulates PRL and androgens secretion. ► Stimulatory effects of atrazine were abolished in cells with IBMX-inhibited PDEs. ► Atrazine specificity toward cAMP-specific PDEs was indicated by no changes in cGMP. ► Rolipram, a specific PDE4 inhibitor, also prevents stimulatory effects of atrazine. ► Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific PDE4.« less

Microbial adaption to a pesticide in agricultural soils: Accelerated degradation of 14C-atrazine in field soils from Brazil and Belgium

NASA Astrophysics Data System (ADS)

Jablonowski, Nicolai David; Martinazzo, Rosane; Hamacher, Georg; Accinelli, Cesare; Köppchen, Stephan; Langen, Ulrike; Linden, Andreas; Krause, Martina; Burauel, Peter

2010-05-01

An increasing demand for food, feed and bioenergy, and simultaneously a decline of arable land will require an intensive agricultural production including the use of pesticides. With an increasing use of pesticides the occurrence of an accelerated degradation potential has to be assessed. Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] is one of the most widely used herbicides in the world. Even though its use was banned in several countries it is still widely used throughout America and the Asia-Pacific region. Atrazine is the most widely used herbicide in maize plantations in Brazil and the US. The use of atrazine in Belgium and all EU member states was banned in September 2004, with the permission to consume existing stocks until October 2005. Atrazine and its residues are still regularly detected in soil, ground and surface waters even years after its prohibition. Its persistence in soil and in association with organic particles might become crucial in terms of erosion due to climate and environmental changes. Due to its potential microbiological accessibility, the microbial mineralization of atrazine competes with chemical/physical interaction such as sorption and binding processes of the chemical molecule in the soil matrix. Binding or intrusion of the chemical on soil components results in a decrease of its accessibility for soil microbes, which does not necessarily exclude the molecule from environmental interactions. In the present study the accelerated atrazine degradation in agriculturally used soils was examined. Soil samples were collected from a Rhodic Ferralsol, Campinas do Sul, South Brazil, and Geric Ferralsol, Correntina, Northeastern Brazil. The sampling site of the Rhodic Ferralsol soil has been under crop rotation (soybean/wheat/maize/oat) since 1990. The Geric Ferralsol site has alternately been cultivated with maize and soybean since 2000. Both areas have been treated biennially with atrazine at recommended doses of 1.5 - 3.0 kg ha-1. Additionally, samples were taken from a Belgian field which was used for corn-plantations and which was regularly treated with atrazine for the last 30 years in varying doses of 0.5 - 3.0 kg ha-1. The experiment was performed using 14C-labelled and unlabelled atrazine in accordance to a field application dose of 3 mg kg-1 for the Brazilian soils, and 1 mg kg-1 for the Belgian soil, equaling approximately 3.0 and 1.0 kg ha-1, respectively. All soils with atrazine application history showed a high extent of atrazine mineralization, indicating a highly adapted microbial community being able to mineralize this pesticide. After 15 days of incubation, about 75 % of the initially applied 14C-atrazine was mineralized in the Rhodic Ferralsol, while in the Geric Ferralsol it did not exceed 15 % of the total applied 14C-activity. After a total incubation time of 85 days, the amount mineralized reached 82 % in the Rhodic Ferralsol and 74 % in the Geric Ferralsol. In the Belgian soil, after a total incubation time of 92 days, the mineralized amount of atrazine reached 83% of the initially applied 14C-activity in the atrazine treated soil for the slurry setup. A maximum of atrazine mineralization was observed in the treated field soil between 6 and 7 days of incubation for both, 50% WHCmax and slurry setups. The total 14C-atrazine mineralization was equally high for 50% WHCmax in the atrazine treated soil, totaling 81%. The formation of desorbable metabolites as well as the formation of unextractable, bound atrazine residues during the incubation process was monitored by desorption and accelerated solvent extraction, and successive LC-MSMS and LSC analyses, subsequent to sample oxidation. With increasing incubation time the presence of atrazine metabolites increased in the extracts, with hydroxyl-atrazine as the main metabolite.

EFFECTS OF ATRAZINE AND AN ATRAZINE METABOLITE MIXTURE ON DIFFERENTIATED MAMMARY EPITHELIAL CELL MILK PROTEIN PRODUCTION IN CULTURE

EPA Science Inventory

Effects of Atrazine and an Atrazine Metabolite Mixture on Differentiated Mammary Epithelial Cell Milk Protein Production in Culture

E.P. Hines, R. Barbee, M. Blanton, M.S. Pooler, and S.E. Fenton. US EPA, ORD/NHEERL, RTD, RTP, NC, 27711, USA.

Previous studies have ...

EVALUATION OF PITUITARY AND ADRENAL HORMONE RELEASE FOLLOWING EXPOSURE TO ATRAZINE AND ITS METABOLITE DEISOPROPYL-ATRAZINE (DIA), USING TISSUE PERIFUSION

EPA Science Inventory

Atrazine (ATR) is one of the most widely used herbicides in the United States, with current total annual use of approximately 76 million pounds of active ingredient. Previous work in our laboratory has shown that ATR and its metabolite deisopropyl-atrazine (DIA) induce a dose-dep...

Sensitivity of Scenedesmus obliquus and Microcystis aeruginosa to atrazine: effects of acclimation and mixed cultures, and their removal ability.

PubMed

Chalifour, Annie; LeBlanc, André; Sleno, Lekha; Juneau, Philippe

2016-12-01

Atrazine is an herbicide frequently detected in watercourses that can affect the phytoplankton community, thus impacting the whole food chain. This study aims, firstly, to measure the sensitivity of monocultures of the green alga Scenedemus obliquus and toxic and non-toxic strains of the cyanobacteria Microcystis aeruginosa before, during and after a 30-day acclimation period to 0.1 µM of atrazine. Secondly, the sensitivity of S. obliquus and M. aeruginosa to atrazine in mixed cultures was evaluated. Finally, the ability of these strains to remove atrazine from the media was measured. We demonstrated that both strains of M. aeruginosa had higher growth rate-based EC 50 values than S. obliquus when exposed to atrazine, even though their photosynthesis-based EC 50 values were lower. After being exposed to 0.1 µM of atrazine for 1 month, only the photosynthesis-based EC 50 of S. obliquus increased significantly. In mixed cultures, the growth rate of the non-toxic strain of M. aeruginosa was higher than S. obliquus at high concentrations of atrazine, resulting in a ratio of M. aeruginosa to total cell count of 0.6. This lower sensitivity might be related to the higher growth rate of cyanobacteria at low light intensity. Finally, a negligible fraction of atrazine was removed from the culture media by S. obliquus or M. aeruginosa over 6 days. These results bring new insights on the acclimation of some phytoplankton species to atrazine and its effect on the competition between S. obliquus and M. aeruginosa in mixed cultures.

Seasonal detection of atrazine and atzA in man-made waterways receiving agricultural runoff in a subtropical, semi-arid environment (Hidalgo County, Texas, USA).

PubMed

Cortez, Ibdanelo; Vitek, Christopher J; Persans, Michael W; Lowe, Kristine L

2017-02-01

Atrazine is a widely-used herbicide that can impact non-target organisms in the environment but can be biologically degraded by several types of microorganisms. In this study, the gene atzA, which encodes for the initial step in bacterially-mediated atrazine degradation, was used as an indicator of atrazine pollution in agricultural canals located in Hidalgo County, Texas, USA. The concentration of atrazine and atzA were monitored once per month for 12 months during 2010-2011. Atrazine was measured using an enzyme-linked immunosorbent assay; atzA abundance was monitored using Quantitative Polymerase Chain Reaction (Q-PCR) analyses. Abundance of atrazine and atzA were compared with rainy versus dry months and during planting versus non-planting months. Results showed that atrazine levels varied from below detection to 0.43 ppb and were not influenced by precipitation or planting season. Concentrations of the gene atzA were significantly different in rainy versus dry months; during planting versus non-planting times of the year; and in the interaction of precipitation and planting season. The highest concentration of atzA, approx. 4.57 × 10 8 gene copies ml -1 , was detected in July 2010-a rainy, planting month in Hidalgo County, South Texas. However, atrazine was below detection during that month. We conclude that Q-PCR using atzA as an indicator gene is a potential method for monitoring low levels of atrazine pollution in environmental samples.

Efficient removal of atrazine from aqueous solutions using magnetic Saccharomyces cerevisiae bionanomaterial.

PubMed

Wu, Xin; He, Huijun; Yang, William L; Yu, Jiaping; Yang, Chunping

2018-06-17

A novel bionanomaterial comprising Saccharomyces cerevisiae (S. cerevisiae) and Fe 3 O 4 nanoparticles encapsulated in a sodium alginate-polyvinyl alcohol (SA-PVA) matrix was synthesized for the efficient removal of atrazine from aqueous solutions. The effects of the operating parameters, nitrogen source, and glucose and Fe 3+ contents on atrazine removal were investigated, and the intermediates were detected by gas chromatography-mass spectrometry (GC-MS). In addition, the synthesized Fe 3 O 4 particles were characterized by XRD, EDX, HR-TEM, FTIR, and hysteresis loops, and the bionanomaterial was characterized by SEM. The results showed that the maximum removal efficiency of 100% was achieved at 28 °C, a pH of 7.0, and 150 rpm with an initial atrazine concentration of 2.0 mg L -1 and that the removal efficiency was still higher than 95.53% even when the initial atrazine concentration was 50 mg L -1 . Biodegradation was demonstrated to be the dominant removal mechanism for atrazine because atrazine was consumed as the sole carbon source for S. cerevisiae. The results of GC-MS showed that dechlorination, dealkylation, deamination, isomerization, and mineralization occurred in the process of atrazine degradation, and thus, a new degradation pathway was proposed. These results indicated that this bionanomaterial has great potential for the bioremediation of atrazine-contaminated water.

Gene expression profiling reveals decreased expression of two hemoglobin genes associated with increased consumption of oxygen in Chironomus tentans exposed to atrazine: a possible mechanism for adapting to oxygen deficiency.

PubMed

Anderson, Troy D; Jin-Clark, Ying; Begum, Khurshida; Starkey, Sharon R; Zhu, Kun Yan

2008-01-31

Atrazine is an extensively used triazine herbicide in agricultural and residential areas and has been routinely detected in many surface and ground waters. This study reveals various up- and down-regulated genes associated with hypoxic stress in atrazine-treated fourth-instar Chironomus tentans larvae (midges) by using restriction fragment differential display-PCR. Two down-regulated hemoglobin cDNAs were isolated from the midges. Northern blot analysis indicated CteHb-IIbeta and CteHb-III mRNA expressions decreased by 36 and 21%, respectively, in midges exposed to atrazine at 1 microg/L for 96h. Decreased hemoglobin gene expression was associated with elevated oxygen consumption in atrazine-treated midges. Midges exposed to atrazine at 1 microg/L increased their oxygen consumption by 47%, whereas midges exposed to atrazine at 1000 microg/L for 48h increased their oxygen consumption by 66%. Our study demonstrates for the first time that atrazine, at environmentally relevant concentrations, can elevate respiration, possibly eliciting counteractive measures at the transcriptional level to adapt to oxygen deficiency in an ecologically important aquatic insect. Our results further suggest that the ability to modulate both the quantity and quality of Hb serves as an adaptive response to counteract the initial onset of oxygen deficiency induced by atrazine in midges.

Embryo-larval exposure to atrazine reduces viability and alters oxidative stress parameters in Drosophila melanogaster.

PubMed

Figueira, Fernanda Hernandes; Aguiar, Lais Mattos de; Rosa, Carlos Eduardo da

2017-01-01

The herbicide atrazine has been used worldwide with subsequent residual contamination of water and food, which may cause adverse effects on non-target organisms. Animal exposure to this herbicide may affect development, reproduction and energy metabolism. Here, the effects of atrazine regarding survival and redox metabolism were assessed in the fruit fly D. melanogaster exposed during embryonic and larval development. The embryos (newly fertilized eggs) were exposed to different atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Pupation and emergence rates, developmental time and sex ratio were determined as well as oxidative stress parameters and gene expression of the antioxidant defence system were evaluated in newly emerged male and female flies. Atrazine exposure reduced pupation and emergence rates in fruit flies without alterations to developmental time and sex ratio. Different redox imbalance patterns were observed between males and females exposed to atrazine. Atrazine caused an increase in oxidative damage, reactive oxygen species generation and antioxidant capacity and decreased thiol-containing molecules. Further, atrazine exposure altered the mRNA expression of antioxidant genes (keap1, sod, sod2, cat, irc, gss, gclm, gclc, trxt, trxr-1 and trxr-2). Reductions in fruit fly larval and pupal viability observed here are likely consequences of the oxidative stress induced by atrazine exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of compost age and composition on the atrazine removal from solution.

PubMed

Tsui, Lo; Roy, William R

2007-01-02

Compost samples from two composting facilities, the Urbana (Illinois) Landscape Recycling Center (ULRC) and Illinois State University (ISU), were selected to examine the effect of compost age on atrazine removal from solution. The ULRC samples were made from yard waste without an additional nitrogen source. The ISU samples were made from yard waste or sawdust with the addition of manure. The 6-month-old ULRC compost had the greater capacity to remove atrazine from solution, which we attributed to its greater organic carbon content. The addition of nitrate into ULRC compost could influence the extent of atrazine removal, but did not have a significant impact on atrazine removal when applied to ISU compost, probably because manure was added to the yard waste to produce the compost. For both ULRC and ISU samples, the presence of sodium azide inhibited atrazine removal, suggesting that microbial activity contributed to the atrazine removal. Metabolic analysis demonstrated that hydroxyatrazine was the major identified metabolite that accumulated in solution before significant ring mineralization could occur. When compared with the ISU compost, the ULRC compost sample had a greater capacity to remove atrazine from solution during the 120 days of study because of the larger humic acid content. The experimental results suggested that less-mature compost may be better suited for environmental applications such as removing atrazine from tile-drainage waters.

Effect of compost age and composition on the atrazine removal from solution

USGS Publications Warehouse

Tsui, L.; Roy, W.R.

2007-01-01

Compost samples from two composting facilities, the Urbana (Illinois) Landscape Recycling Center (ULRC) and Illinois State University (ISU), were selected to examine the effect of compost age on atrazine removal from solution. The ULRC samples were made from yard waste without an additional nitrogen source. The ISU samples were made from yard waste or sawdust with the addition of manure. The 6-month-old ULRC compost had the greater capacity to remove atrazine from solution, which we attributed to its greater organic carbon content. The addition of nitrate into ULRC compost could influence the extent of atrazine removal, but did not have a significant impact on atrazine removal when applied to ISU compost, probably because manure was added to the yard waste to produce the compost. For both ULRC and ISU samples, the presence of sodium azide inhibited atrazine removal, suggesting that microbial activity contributed to the atrazine removal. Metabolic analysis demonstrated that hydroxyatrazine was the major identified metabolite that accumulated in solution before significant ring mineralization could occur. When compared with the ISU compost, the ULRC compost sample had a greater capacity to remove atrazine from solution during the 120 days of study because of the larger humic acid content. The experimental results suggested that less-mature compost may be better suited for environmental applications such as removing atrazine from tile-drainage waters. ?? 2006 Elsevier B.V. All rights reserved.

Comparing the clastogenic potential of atrazine with caffeine using Chinese hamster ovary (CHO) cells.

PubMed

Rayburn, A L; Bouma, J; Northcott, C A

2001-04-08

The agronomically important herbicide atrazine has been reported to cause damage to animal chromosomes at levels of atrazine found contaminating drinking water supplies. While documenting potential chromosome damage is important it is equally important to compare the damage with the potential consequences of compounds readily found in our food and water supply. In this study atrazine and caffeine, a ubiquitous food additive, were compared at equal levels and at real exposure levels for their ability to damage animals chromosomes in cell culture. Nuclei and chromosomes from treated and control cells were analyzed by flow cytometry. At extremely low levels, atrazine was found to be a more potent clastogen. Caffeine had no effect on the chromosomes at the lower levels. Both chemicals were genotoxic at the potential exposure levels with caffeine being more disruptive than atrazine. Atrazine appears to be a more potent damaging agent than caffeine at similar levels of exposure; however, the levels of caffeine one is exposed to during everyday life appears to be more damaging on the endpoints analyzed in this study than the levels of atrazine found contaminating water supplies. The advantages and limitations of whole cell clasotgenicity are also presented in light of these results.

Atrazine reduces reproduction in fathead minnow (Pimephales promelas): raw data report

USGS Publications Warehouse

Tillitt, Donald E.; Papoulias, Diana M.; Whyte, Jeffrey J.; Richter, Catherine A.

2014-01-01

The herbicide, atrazine, routinely is observed in surface and groundwaters, particularly in the “corn belt” region, a high-use area of the United States. Atrazine has demonstrated effects on reproduction in mammals and amphibians, but the characterization of endocrine-related effects in fish has received only limited attention. Peak concentrations of atrazine in surface water of streams from these agricultural areas coincide with annual spawning events of native fishes. Consequently, there was an unacceptable level of uncertainty in our understanding of the risks associated with the periods of greatest atrazine exposure and greatest vulnerability of certain species of fishes. For this reason, a study of the effects of atrazine on fathead minnow reproduction was undertaken (Tillitt and others, 2010). This report provides the raw data from that study.

Ground-water quality in agricultural areas, Anoka Sand Plain Aquifer, east-central Minnesota, 1984-90

USGS Publications Warehouse

Landon, M.K.; Delin, G.N.

1995-01-01

Concentrations of atrazine and DEA generally were greater near the water table and decreased or were not detected in deeper wells. All of the samples in which atrazine and DEA were detected also had increased (greater than 3 mg/L) nitrate-N concentrations. However, not all samples with increased concentrations of nitrate-N had detections of atrazine or DEA. This likely indicates either that there were sources of nitrate-N other than cultivated fields on which both atrazine and nitrogen were applied or that nitrate-N reached ground water more readily than atrazine or DEA.

Community drinking water quality monitoring data: utility for public health research and practice.

PubMed

Jones, Rachael M; Graber, Judith M; Anderson, Robert; Rockne, Karl; Turyk, Mary; Stayner, Leslie T

2014-01-01

Environmental Public Health Tracking (EPHT) tracks the occurrence and magnitude of environmental hazards and associated adverse health effects over time. The EPHT program has formally expanded its scope to include finished drinking water quality. Our objective was to describe the features, strengths, and limitations of using finished drinking water quality data from community water systems (CWSs) for EPHT applications, focusing on atrazine and nitrogen compounds in 8 Midwestern states. Water quality data were acquired after meeting with state partners and reviewed and merged for analysis. Data and the coding of variables, particularly with respect to censored results (nondetects), were not standardized between states. Monitoring frequency varied between CWSs and between atrazine and nitrates, but this was in line with regulatory requirements. Cumulative distributions of all contaminants were not the same in all states (Peto-Prentice test P < .001). Atrazine results were highly censored in all states (76.0%-99.3%); higher concentrations were associated with increased measurement frequency and surface water as the CWS source water type. Nitrate results showed substantial state-to-state variability in censoring (20.5%-100%) and in associations between concentrations and the CWS source water type. Statistical analyses of these data are challenging due to high rates of censoring and uncertainty about the appropriateness of parametric assumptions for time-series data. Although monitoring frequency was consistent with regulations, the magnitude of time gaps coupled with uncertainty about CWS service areas may limit linkage with health outcome data.

Probability of detecting atrazine/desethyl-atrazine and elevated concentrations of nitrate plus nitrate as nitrogen in ground water in the Idaho part of the western Snake River Plain

USGS Publications Warehouse

Donato, Mary M.

2000-01-01

As ground water continues to provide an ever-growing proportion of Idaho?s drinking water, concerns about the quality of that resource are increasing. Pesticides (most commonly, atrazine/desethyl-atrazine, hereafter referred to as atrazine) and nitrite plus nitrate as nitrogen (hereafter referred to as nitrate) have been detected in many aquifers in the State. To provide a sound hydrogeologic basis for atrazine and nitrate management in southern Idaho—the largest region of land and water use in the State—the U.S. Geological Survey produced maps showing the probability of detecting these contaminants in ground water in the upper Snake River Basin (published in a 1998 report) and the western Snake River Plain (published in this report). The atrazine probability map for the western Snake River Plain was constructed by overlaying ground-water quality data with hydrogeologic and anthropogenic data in a geographic information system (GIS). A data set was produced in which each well had corresponding information on land use, geology, precipitation, soil characteristics, regional depth to ground water, well depth, water level, and atrazine use. These data were analyzed by logistic regression using a statistical software package. Several preliminary multivariate models were developed and those that best predicted the detection of atrazine were selected. The multivariate models then were entered into a GIS and the probability maps were produced. Land use, precipitation, soil hydrologic group, and well depth were significantly correlated with atrazine detections in the western Snake River Plain. These variables also were important in the 1998 probability study of the upper Snake River Basin. The effectiveness of the probability models for atrazine might be improved if more detailed data were available for atrazine application. A preliminary atrazine probability map for the entire Snake River Plain in Idaho, based on a data set representing that region, also was produced. In areas where this map overlaps the 1998 map of the upper Snake River Basin, the two maps show broadly similar probabilities of detecting atrazine. Logistic regression also was used to develop a preliminary statistical model that predicts the probability of detecting elevated nitrate in the western Snake River Plain. A nitrate probability map was produced from this model. Results showed that elevated nitrate concentrations were correlated with land use, soil organic content, well depth, and water level. Detailed information on nitrate input, specifically fertilizer application, might have improved the effectiveness of this model.

AERO2S - SUBSONIC AERODYNAMIC ANALYSIS OF WINGS WITH LEADING- AND TRAILING-EDGE FLAPS IN COMBINATION WITH CANARD OR HORIZONTAL TAIL SURFACES (CDC VERSION)

NASA Technical Reports Server (NTRS)

Darden, C. M.

1994-01-01

This code was developed to aid design engineers in the selection and evaluation of aerodynamically efficient wing-canard and wing-horizontal-tail configurations that may employ simple hinged-flap systems. Rapid estimates of the longitudinal aerodynamic characteristics of conceptual airplane lifting surface arrangements are provided. The method is particularly well suited to configurations which, because of high speed flight requirements, must employ thin wings with highly swept leading edges. The code is applicable to wings with either sharp or rounded leading edges. The code provides theoretical pressure distributions over the wing, the canard or horizontal tail, and the deflected flap surfaces as well as estimates of the wing lift, drag, and pitching moments which account for attainable leading edge thrust and leading edge separation vortex forces. The wing planform information is specified by a series of leading edge and trailing edge breakpoints for a right hand wing panel. Up to 21 pairs of coordinates may be used to describe both the leading edge and the trailing edge. The code has been written to accommodate 2000 right hand panel elements, but can easily be modified to accommodate a larger or smaller number of elements depending on the capacity of the target computer platform. The code provides solutions for wing surfaces composed of all possible combinations of leading edge and trailing edge flap settings provided by the original deflection multipliers and by the flap deflection multipliers. Up to 25 pairs of leading edge and trailing edge flap deflection schedules may thus be treated simultaneously. The code also provides for an improved accounting of hinge-line singularities in determination of wing forces and moments. To determine lifting surface perturbation velocity distributions, the code provides for a maximum of 70 iterations. The program is constructed so that successive runs may be made with a given code entry. To make additional runs, it is necessary only to add an identification record and the namelist data that are to be changed from the previous run. This code was originally developed in 1989 in FORTRAN V on a CDC 6000 computer system, and was later ported to an MS-DOS environment. Both versions are available from COSMIC. There are only a few differences between the PC version (LAR-14458) and CDC version (LAR-14178) of AERO2S distributed by COSMIC. The CDC version has one main source code file while the PC version has two files which are easier to edit and compile on a PC. The PC version does not require a FORTRAN compiler which supports NAMELIST because a special INPUT subroutine has been added. The CDC version includes two MODIFY decks which can be used to improve the code and prevent the possibility of some infrequently occurring errors while PC-version users will have to make these code changes manually. The PC version includes an executable which was generated with the Ryan McFarland/FORTRAN compiler and requires 253K RAM and an 80x87 math co-processor. Using this executable, the sample case requires about four hours to execute on an 8MHz AT-class microcomputer with a co-processor. The source code conforms to the FORTRAN 77 standard except that it uses variables longer than six characters. With two minor modifications, the PC version should be portable to any computer with a FORTRAN compiler and sufficient memory. The CDC version of AERO2S is available in CDC NOS Internal format on a 9-track 1600 BPI magnetic tape. The PC version is available on a set of two 5.25 inch 360K MS-DOS format diskettes. IBM AT is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. CDC is a registered trademark of Control Data Corporation. NOS is a trademark of Control Data Corporation.

Regression models for estimating concentrations of atrazine plus deethylatrazine in shallow groundwater in agricultural areas of the United States

USGS Publications Warehouse

Stackelberg, Paul E.; Barbash, Jack E.; Gilliom, Robert J.; Stone, Wesley W.; Wolock, David M.

2012-01-01

Tobit regression models were developed to predict the summed concentration of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and its degradate deethylatrazine [6-chloro-N-(1-methylethyl)-1,3,5,-triazine-2,4-diamine] (DEA) in shallow groundwater underlying agricultural settings across the conterminous United States. The models were developed from atrazine and DEA concentrations in samples from 1298 wells and explanatory variables that represent the source of atrazine and various aspects of the transport and fate of atrazine and DEA in the subsurface. One advantage of these newly developed models over previous national regression models is that they predict concentrations (rather than detection frequency), which can be compared with water quality benchmarks. Model results indicate that variability in the concentration of atrazine residues (atrazine plus DEA) in groundwater underlying agricultural areas is more strongly controlled by the history of atrazine use in relation to the timing of recharge (groundwater age) than by processes that control the dispersion, adsorption, or degradation of these compounds in the saturated zone. Current (1990s) atrazine use was found to be a weak explanatory variable, perhaps because it does not represent the use of atrazine at the time of recharge of the sampled groundwater and because the likelihood that these compounds will reach the water table is affected by other factors operating within the unsaturated zone, such as soil characteristics, artificial drainage, and water movement. Results show that only about 5% of agricultural areas have greater than a 10% probability of exceeding the USEPA maximum contaminant level of 3.0 μg L-1. These models are not developed for regulatory purposes but rather can be used to (i) identify areas of potential concern, (ii) provide conservative estimates of the concentrations of atrazine residues in deeper potential drinking water supplies, and (iii) set priorities among areas for future groundwater monitoring.

Habitat fragmentation caused by contaminants: Atrazine as a chemical barrier isolating fish populations.

PubMed

Araújo, Cristiano V M; Silva, Daniel C V R; Gomes, Luiz E T; Acayaba, Raphael D; Montagner, Cassiana C; Moreira-Santos, Matilde; Ribeiro, Rui; Pompêo, Marcelo L M

2018-02-01

Information on how atrazine can affect the spatial distribution of organisms is non-existent. As this effect has been observed for some other contaminants, we hypothesized that atrazine-containing leachates/discharges could trigger spatial avoidance by the fish Poecilia reticulata and form a chemical barrier isolating upstream and downstream populations. Firstly, guppies were exposed to an atrazine gradient in a non-forced exposure system, in which organisms moved freely among the concentrations, to assess their ability to avoid atrazine. Secondly, a chemical barrier formed by atrazine, separating two clean habitats (extremities of the non-forced system), was simulated to assess whether the presence of the contaminant could prevent guppies from migrating to the other side of the system. Fish were able to avoid atrazine contamination at environmentally relevant concentrations (0.02 μg L -1 ), below those described to cause sub-lethal effects. The AC 50 (atrazine concentration causing avoidance to 50% of the population) was 0.065 μg L -1 . The chemical barrier formed by atrazine at 150 μg L -1 (concentration that should produce an avoidance around 82%) caused a reduction in the migratory potential of the fish by 47%; while the chemical barrier at 1058 μg L -1 (concentration that produces torpidity) caused a reduction in the migratory potential of the fish by 91%. Contamination by atrazine, besides driving the spatial distribution of fish populations, has potential to act as a chemical barrier by isolating fish populations. This study includes a novel approach to be integrated in environmental risk assessment schemes to assess high-tier contamination effects such as habitat fragmentation and population displacement and isolation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of atrazine and chlorothalonil on the reproductive success, development, and growth of early life stage sockeye salmon (Oncorhynchus nerka).

PubMed

Du Gas, Lindsay M; Ross, Peter S; Walker, Janessa; Marlatt, Vicki L; Kennedy, Christopher J

2017-05-01

The effects of 2 currently used commercial pesticide formulations on Pacific sockeye salmon (Oncorhynchus nerka), from fertilization to emergence, were evaluated in a gravel-bed flume incubator that simulated a natural streambed. Embryos were exposed to atrazine at 25 µg/L (low atrazine) or atrazine at 250 µg/L (high atrazine) active ingredient (a.i.), and chlorothalonil at 0.5 µg/L (low chlorothalonil) or chlorothalonil at 5 µg/L a.i. (high chlorothalonil) and examined for effects on developmental success and timing, as well as physical and biochemical growth parameters. Survival to hatch was reduced in the high chlorothalonil group (55% compared with 83% in controls), accompanied by a 24% increase in finfold deformity incidence. Reduced alevin condition factor (2.9-5.4%) at emergence and elevated triglyceride levels were seen in chlorothalonil-exposed fish. Atrazine exposure caused premature hatch (average high atrazine time to 50% hatch [H50] = 100 d postfertilization [dpf]), and chlorothalonil exposure caused delayed hatch (high chlorothalonil H50 = 108 dpf; controls H50 = 102 dpf). All treatments caused premature emergence (average time to 50% emergence [E50]: control E50 = 181 dpf, low chlorothalonil E50 = 175 dpf, high chlorothalonil E50 = 174 dpf, high atrazine E50 = 175 dpf, low atrazine E50 = 174 dpf), highlighting the importance of using a gravel-bed incubator to examine this subtle, but critical endpoint. These alterations indicate that atrazine and chlorothalonil could affect survival of early life stages of sockeye salmon in the wild. Environ Toxicol Chem 2017;36:1354-1364. © 2017 SETAC. © 2017 SETAC.

Microscopic examination on cytological changes in Allium cepa and shift in phytoplankton population at different doses of Atrazine

NASA Astrophysics Data System (ADS)

Ghosh, Nabarun; Finger, Kristen; Usnick, Samantha; Rogers, William J.; Das, A. B.; Smith, Don W.

2010-06-01

Atrazine is a wide-range herbicide. For over 50 years, atrazine has been used as a selective broadleaf herbicide in many capacities, from pre-plant to pre-emergence to post-emergence, depending on the crop and application. Currently, 96% of all atrazine used is for commercial applications in fields for the control of broadleaf and grassy weeds in crops such as sorghum, corn, sugarcane, pineapple and for the control of undesirable weeds in rangeland. Many panhandle wells have also detected atrazine in samples taken. The concern for the public is the long-term effect of atrazine with its increasing popularity, and the impact on public health. We investigated the effect of different concentrations of atrazine on Allium cepa (onion), a standard plant test system. We established a control with the Allium bulbs grown on hydroponics culture. Varying concentrations of atrazine was used on the standard plant test system, Allium cepa grown hydroponically. The mitotic indices varied and with higher doses, we observed various chromosomal abnormalities including sticky bridges, early and late separations, and lag chromosomes with higher doses of treatments. In the second part of the experiment, 0.1ppb, 1ppb, 10ppb, and 100ppb concentrations of atrazine were applied to established phytoplankton cultures from the Lake Tanglewood, Texas. Study with a Sedgwick-Rafter counter, a BX-40 Olympus microscope with DP-70 camera revealed a gradual shift in the phytoplankton community from obligatory to facultative autotroph and finally to a parasitic planktonic community. This explains the periodic fish kill in the lakes after applications of atrazine in crop fields.

Evaluation of the agronomic performance of atrazine-tolerant transgenic japonica rice parental lines for utilization in hybrid seed production.

PubMed

Zhang, Luhua; Chen, Haiwei; Li, Yanlan; Li, Yanan; Wang, Shengjun; Su, Jinping; Liu, Xuejun; Chen, Defu; Chen, Xiwen

2014-01-01

Currently, the purity of hybrid seed is a crucial limiting factor when developing hybrid japonica rice (Oryza sativa L.). To chemically control hybrid seed purity, we transferred an improved atrazine chlorohydrolase gene (atzA) from Pseudomonas ADP into hybrid japonica parental lines (two maintainers, one restorer), and Nipponbare, by using Agrobacterium-mediated transformation. We subsequently selected several transgenic lines from each genotype by using PCR, RT-PCR, and germination analysis. In the presence of the investigated atrazine concentrations, particularly 150 µM atrazine, almost all of the transgenic lines produced significantly larger seedlings, with similar or higher germination percentages, than did the respective controls. Although the seedlings of transgenic lines were taller and gained more root biomass compared to the respective control plants, their growth was nevertheless inhibited by atrazine treatment compared to that without treatment. When grown in soil containing 2 mg/kg or 5 mg/kg atrazine, the transgenic lines were taller, and had higher total chlorophyll contents than did the respective controls; moreover, three of the strongest transgenic lines completely recovered after 45 days of growth. After treatment with 2 mg/kg or 5 mg/kg of atrazine, the atrazine residue remaining in the soil was 2.9-7.0% or 0.8-8.7% respectively, for transgenic lines, and 44.0-59.2% or 28.1-30.8%, respectively, for control plants. Spraying plants at the vegetative growth stage with 0.15% atrazine effectively killed control plants, but not transgenic lines. Our results indicate that transgenic atzA rice plants show tolerance to atrazine, and may be used as parental lines in future hybrid seed production.

Atrazine in public water supplies and risk of ovarian cancer among postmenopausal women in the Iowa Women’s Health Study

PubMed Central

Inoue-Choi, Maki; Weyer, Peter J; Jones, Rena R; Booth, Benjamin J; Cantor, Kenneth P; Robien, Kim; Ward, Mary H

2016-01-01

Background Few studies have evaluated environmental chemical exposures in relation to ovarian cancer. We previously found an increased risk of ovarian cancer among postmenopausal women in Iowa associated with higher nitrate levels in public water supplies (PWS). However, elevated nitrate levels may reflect the presence of other agricultural chemicals, such as atrazine, one of the most commonly detected pesticides in Iowa PWS. Methods We evaluated the association between atrazine in drinking water and incident ovarian cancer (N=145, 1986–2010) among 13 041 postmenopausal women in the Iowa Women’s Health Study who used their PWS for ≥11 years as reported in 1989. Average levels of atrazine (1986–1987), nitrate-nitrogen (NO3-N, 1955–1988) and estimated levels of total trihalomethanes (TTHM, 1955–1988) from PWS monitoring data were linked to the participants’ cities of residence. We computed HRs and 95% CIs by categories of the average atrazine level (not detected, ≤ or >0.37 parts per billion=median) using Cox proportional hazards regression adjusting for ovarian cancer risk factors. Results Atrazine was detected in water samples from 69 cities where 4155 women (32%) lived and levels were moderately correlated with NO3-N (ρ=0.35) and TTHM (ρ=0.24). Atrazine levels were not associated with ovarian cancer risk with or without adjusting for NO3-N and TTHM levels ( p-trend=0.50 and 0.81, respectively). Further, there was no evidence for effect modification of the atrazine association by NO3-N or TTHM levels. Conclusions In our study with low atrazine detection rates, we found no association between atrazine in PWS and postmenopausal ovarian cancer risk. PMID:27371663

Cellulases and coding sequences

DOEpatents

Li, Xin-Liang; Ljungdahl, Lars G.; Chen, Huizhong

2001-02-20

The present invention provides three fungal cellulases, their coding sequences, recombinant DNA molecules comprising the cellulase coding sequences, recombinant host cells and methods for producing same. The present cellulases are from Orpinomyces PC-2.

Cellulases and coding sequences

DOEpatents

Li, Xin-Liang; Ljungdahl, Lars G.; Chen, Huizhong

2001-01-01

The present invention provides three fungal cellulases, their coding sequences, recombinant DNA molecules comprising the cellulase coding sequences, recombinant host cells and methods for producing same. The present cellulases are from Orpinomyces PC-2.

Aquatic Life Criteria - Atrazine

EPA Pesticide Factsheets

Documents pertaining to Acute and Chronic Ambient Water Quality Aquatic Life Criteria for Atrazine (Freshwater and Salt Water). This document contains the safe levels of Atrazine in water that should protect to the majority of species.

The Effect of Atrazine on Louisiana Gulf Coast Estuarine Phytoplankton.

PubMed

Starr, Alexis V; Bargu, Sibel; Maiti, Kanchan; DeLaune, Ronald D

2017-02-01

Pesticides may enter water bodies in areas with a high proportion of agricultural land use through surface runoff, groundwater discharge, and erosion and thus negatively impact nontarget aquatic organisms. The herbicide atrazine is used extensively throughout the Midwest and enters the Mississippi River through surface runoff and groundwater discharge. The purpose of this study was to determine the extent of atrazine contamination in Louisiana's estuaries from Mississippi River water under different flow and nutrient regimes (spring and summer) and its effect on the biomass and oxygen production of the local phytoplankton community. The results showed that atrazine was consistently present in these systems at low levels. Microcosm experiments exposed to an atrazine-dilution series under low and high nutrient conditions to determine the phytoplankton stress response showed that high atrazine levels greatly decreased phytoplankton biomass and oxygen production. Phytoplankton exposed to low and moderate atrazine levels under high nutrient conditions were able to recover after an extended acclimation period. Communities grown under high nutrient conditions grew more rapidly and produced greater levels of oxygen than the low nutrient treatment groups, thus indicating that atrazine exposure may induce a greater stress response in phytoplankton communities under low-nutrient conditions. The native community also experienced a shift from more sensitive species, such as chlorophytes, to potentially more resilient species such as diatoms. The phytoplankton response to atrazine exposure at various concentrations can be especially important to greater trophic levels because their growth and abundance can determine the potential productivity of the entire ecosystem.

Atrazine retention and degradation in the vadose zone at a till plain site in central Indiana

USGS Publications Warehouse

Bayless, E.R.

2001-01-01

The vadose zone was examined as an environmental compartment where significant quantities of atrazine and its degradation compounds may be stored and transformed. The vadose zone was targeted because regional studies in the White River Basin indicated a large discrepancy between the mass of atrazine applied to fields and the amount of the pesticide and its degradation compounds that are measured in ground and surface water. A study site was established in a rotationally cropped field in the till plain of central Indiana. Data were gathered during the 1994 growing season to characterize the site hydrogeology and the distribution of atrazine, desethylatrazine, deisopropylatrazine, didealkylatrazine and hydroxyatrazine in runoff, pore water, and ground water. The data indicated that atrazine and its degradation compounds were transported from land surface to a depth of 1.5 m within 60 days of application, but were undetected in the saturated zone at nearby monitoring wells. A numerical model was developed, based on the field data, to provide information about processes that could retain and degrade atrazine in the vadose zone. Simulations indicated that evapotranspiration is responsible for surface directed soil-moisture flow during much of the growing season. This process causes retention and degradation of atrazine in the vadose zone. Increased residence time in the vadose zone leads to nearly complete transformation of atrazine and its degradation products to unquantified degradation compounds. As a result of mascropore flow, small quantities of atrazine and its degradation compounds may reach the saturated zone.

Effects of atrazine on estrogen receptor α- and G protein-coupled receptor 30-mediated signaling and proliferation in cancer cells and cancer-associated fibroblasts.

PubMed

Albanito, Lidia; Lappano, Rosamaria; Madeo, Antonio; Chimento, Adele; Prossnitz, Eric R; Cappello, Anna Rita; Dolce, Vincenza; Abonante, Sergio; Pezzi, Vincenzo; Maggiolini, Marcello

2015-05-01

The pesticide atrazine does not bind to or activate the classical estrogen receptor (ER), but it up-regulates the aromatase activity in estrogen-sensitive tumor cells. The G protein estrogen receptor (GPR30/GPER) has been reported to be involved in certain biological responses to endogenous estrogens and environmental compounds exerting estrogen-like activity. We aimed to evaluate the potential of atrazine to trigger GPER-mediated signaling in cancer cells and cancer-associated fibroblasts (CAFs). Using gene reporter assays in diverse types of cancer cells, we found that atrazine did not transactivate endogenous ERα or chimeric proteins that encode the ERα and ERβ hormone binding domains. Conversely, atrazine was able to bind to GPER to induce ERK activation and the expression of estrogen target genes, which, interestingly, appeared to rely on both GPER and ERα expression. As a biological counterpart, atrazine stimulated the proliferation of ovarian cancer cells that depend on GPER and ERα, as evidenced by gene silencing experiments and the use of specific signaling inhibitors. Of note, through GPER, atrazine elicited ERK phosphorylation, gene expression, and migration in CAFs, thus extending its stimulatory role to these main players of the tumor microenvironment. Our results suggest a novel mechanism through which atrazine may exert relevant biological effects in cancer cells and CAFs. On the basis of our data, atrazine should be included among the environmental contaminants that may elicit estrogenic activity through GPER-mediated signaling.

Effect of dairy manure rate and the stabilization time of amended soils on atrazine degradation.

PubMed

Aguilera, Paula; Briceño, Gabriela; Candia, Maribel; Mora, Maria de la Luz; Demanet, Rolando; Palma, Graciela

2009-10-01

The application rate of liquid cow manure (LCM) in the field and the stabilization time of amended soils before application of pre-plant herbicides are factors that determine their efficiency. This study includes evaluation of residual atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in soil and amended soils with equivalent rate of 100,000; 200,000; and 300,000 L ha(-1) of LCM and the effect of pre-incubation time of amended soils on atrazine degradation. The study was carried out under controlled conditions using an Andisol with previous historical application of atrazine. The respiratory activity and fluorescein diacetate (FDA) studies indicated that the time necessary for stabilization of amended soils is over 20-30 d. During the measurement of respiratory and FDA activity, no significant differences were observed when atrazine was applied. The half-life of atrazine ranged from 5 to 8d and the relative distribution of degradation products seem to be affected by the application of LCM. The pre-incubation time of amended soil and LCM dose would not affect atrazine degradation rate, when the soil has a history of herbicide application. However, repeated applications of LCM in a long period of time could change the soil pH and increase the content of dissolved organic carbon (DOC) which could further contribute to a faster degradation of atrazine. Both effects would reduce the effectiveness of atrazine in weed control.

Spatial variability of atrazine and metolachlor dissipation on dryland no-tillage crop fields in Colorado.

PubMed

Bridges, Melissa; Henry, W Brien; Shaner, Dale L; Khosla, R; Westra, Phil; Reich, Robin

2008-01-01

An area of interest in precision farming is variable-rate application of herbicides to optimize herbicide use efficiency and minimize negative off-site and non-target effects. Site-specific weed management based on field scale management zones derived from soil characteristics known to affect soil-applied herbicide efficacy could alleviate challenges posed by post-emergence precision weed management. Two commonly used soil-applied herbicides in dryland corn (Zea mays L.) production are atrazine and metolachlor. Accelerated dissipation of atrazine has been discovered recently in irrigated corn fields in eastern Colorado. The objectives of this study were (i) to compare the rates of dissipation of atrazine and metolachlor across different soil zones from three dryland no-tillage fields under laboratory incubation conditions and (ii) to determine if rapid dissipation of atrazine and/or metolachlor occurred in dryland soils. Herbicide dissipation was evaluated at time points between 0 and 35 d after soil treatment using a toluene extraction procedure with GC/MS analysis. Differential rates of atrazine and metolachlor dissipation occurred between two soil zones on two of three fields evaluated. Accelerated atrazine dissipation occurred in soil from all fields of this study, with half-lives ranging from 1.8 to 3.2 d in the laboratory. The rapid atrazine dissipation rates were likely attributed to the history of atrazine use on all fields investigated in this study. Metolachlor dissipation was not considered accelerated and exhibited half-lives ranging from 9.0 to 10.7 d in the laboratory.

Response of ligninolytic macrofungi to the herbicide atrazine: dose-response bioassays.

PubMed

Cupul, Wilberth Chan; Abarca, Gabriela Heredia; Vázquez, Refugio Rodríguez; Salmones, Dulce; Hernández, Rigoberto Gaitán; Gutiérrez, Enrique Alarcón

2014-01-01

The effect of atrazine concentrations on mycelial growth and ligninolytic enzyme activities of eight native ligninolytic macrofungi isolated in Veracruz, México, were evaluated in a semi-solid culture medium. Inhibition of mycelial growth and growth rates were significantly affected (p=0.05) by atrazine concentrations (468, 937, 1875, and 3750 mg/l). In accordance with the median effective concentration (EC50), Pleurotus sp. strain 1 proved to be the most tolerant isolate to atrazine (EC50=2281.0 mg/l), although its enzyme activity was not the highest. Pycnoporus sanguineus strain 2, Daedalea elegans and Trametes maxima showed high laccase activity (62.7, 31.9, 29.3 U mg/protein, respectively) without atrazine (control); however, this activity significantly increased (p<0.05) (to 191.1, 83.5 and 120.6 U mg/protein, respectively) owing to the effect of atrazine (937 mg/l) in the culture medium. Pleurotus sp. strain 2 and Cymatoderma elegans significantly increased (p<0.05) their manganese peroxidase (MnP) activities under atrazine stress at 468 mg/l. The isolates with high EC50 (Pleurotus sp. strain 1) and high enzymatic activity (P. sanguineus strain 2 and T. maxima) could be considered for future studies on atrazine mycodegradation. Furthermore, this study confirms that atrazine can increase laccase and MnP activities in ligninolytic macrofungi. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

Atrazine increases the sodium absorption in frog (Rana esculenta) skin.

PubMed

Cassano, Giuseppe; Bellantuono, Vito; Ardizzone, Concetta; Lippe, Claudio

2006-02-01

The presence of atrazine in agricultural sites has been linked to the decline in amphibian populations. The efforts of the scientific community generally are directed toward investigating the long-term effect of atrazine on complex functions (reproduction or respiration), but in the present study, we investigated the short-term effect on the short-circuit current (I(sc)), a quantitative measure of the ion transport operated by frog (Rana esculenta) skin. Treatment with 5 microM atrazine (1.08 mg/L) does not affect the transepithelial outfluxes of [14C]mannitol or [14C]urea; therefore, atrazine does not damage the barrier properties of frog skin. Atrazine causes a dose-dependent increase in the short-circuit current, with a minimum of 4.64 +/- 0.76 microA/cm2 (11.05% +/- 1.22%) and a maximum of 12.7 +/- 0.7 microA/cm2 (35% +/- 2.4%) measured at 10 nM and 5 microM, respectively. An increase in Isc also is caused by 5 microM ametryne, prometryn, simazine, terbuthylazine, or terbutryn (other atrazine derivatives). In particular, atrazine increases the transepithelial 22Na+ influx without affecting the outflux. Finally, stimulation of Isc by atrazine is suppressed by SQ 22536, H89, U73122, 2-aminoethoxydiphenyl borate, and W7 (blockers of adenylate cyclase, protein kinase A, phospholipase C, intracellular Ca2+ increase, and calmodulin, respectively), whereas indomethacin and calphostin C (inhibitors of cyclooxygenase and protein kinase C, respectively) have no effect.

Would banning atrazine benefit farmers?

PubMed Central

Ackerman, Frank; Whited, Melissa; Knight, Patrick

2014-01-01

Atrazine, an herbicide used on most of the US corn (maize) crop, is the subject of ongoing controversy, with increasing documentation of its potentially harmful health and environmental impacts. Supporters of atrazine often claim that it is of great value to farmers; most recently, Syngenta, the producer of atrazine, sponsored an “Atrazine Benefits Team” (ABT) of researchers who released a set of five papers in 2011, reporting huge economic benefits from atrazine use in US agriculture. A critical review of the ABT papers shows that they have underestimated the growing problem of atrazine-resistant weeds, offered only a partial review of the effectiveness of alternative herbicides, and ignored the promising option of non-chemical weed management techniques. In addition, the most complete economic analysis in the ABT papers implies that withdrawal of atrazine would lead to a decrease in corn yields of 4.4% and an increase in corn prices of 8.0%. The result would be an increase in corn growers’ revenues, equal to US$1.7 billion annually under ABT assumptions. Price impacts on consumers would be minimal: at current levels of ethanol production and use, gasoline prices would rise by no more than US$0.03 per gallon; beef prices would rise by an estimated US$0.01 for a 4-ounce hamburger and US$0.05 for an 8-ounce steak. Thus withdrawal of atrazine would boost farm revenues, while only changing consumer prices by pennies. PMID:24804340

Similarities and differences in occurrence and temporal fluctuations in glyphosate and atrazine in small Midwestern streams (USA) during the 2013 growing season

USGS Publications Warehouse

Mahler, Barbara J.; Van Metre, Peter C.; Burley, Thomas E.; Loftin, Keith A.; Meyer, Michael T.; Nowell, Lisa H.

2017-01-01

Glyphosate and atrazine are the most intensively used herbicides in the United States. Although there is abundant spatial and temporal information on atrazine occurrence at regional scales, there are far fewer data for glyphosate, and studies that compare the two herbicides are rare. We investigated temporal patterns in glyphosate and atrazine concentrations measured weekly during the 2013 growing season in 100 small streams in the Midwestern United States. Glyphosate was detected in 44% of samples (method reporting level 0.2 μg/L); atrazine was detected above a threshold of 0.2 μg/L in 54% of samples. Glyphosate was detected more frequently in 12 urban streams than in 88 agricultural streams, and at concentrations similar to those in streams with high agricultural land use (> 40% row crop) in the watershed. In contrast, atrazine was detected more frequently and at higher concentrations in agricultural streams than in urban streams. The maximum concentration of glyphosate measured at most urban sites exceeded the maximum atrazine concentration, whereas at agricultural sites the reverse was true. Measurement at a 2-day interval at 8 sites in northern Missouri revealed that transport of both herbicide compounds appeared to be controlled by spring flush, that peak concentration duration was brief, but that peaks in atrazine concentrations were of longer duration than those of glyphosate. The 2-day sampling also indicated that weekly sampling is unlikely to capture peak concentrations of glyphosate and atrazine.

Impact of atrazine prohibition on the sustainability of weed management in Wisconsin maize production.

PubMed

Dong, Fengxia; Mitchell, Paul D; Davis, Vince M; Recker, Ross

2017-02-01

Controversy has surrounded atrazine owing to its susceptibility to leaching and run-off, with regular calls for a ban or restrictions on its use. In the context of a decreasing trend in the percentage of US maize using no-till since 2008, coinciding with the trend of glyphosate-resistant weeds becoming problematic in the Midwestern United States, we empirically examine how atrazine use restrictions have impacted the diversity of weed management practices used by Wisconsin maize farmers. Using survey data from farms inside and outside atrazine prohibition areas, we found that prohibiting atrazine did not directly impact tillage practices, but rather it increased the adoption of herbicide-resistant seed, which then increased adoption of conservation tillage systems. We also found that prohibiting atrazine and using herbicide-resistant seed reduced the number of herbicide sites of action used. The results indicate that prohibiting atrazine reduced the diversity of weed management practices, which increased the risk of herbicide resistance. Our concern is that a regulatory policy to address one issue (atrazine in groundwater) has induced farmer responses that increase problems with another issue (herbicide-resistant weeds) that longer term will contribute to water quality problems from increased soil erosion and offset the initial benefits. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Beta.-glucosidase coding sequences and protein from orpinomyces PC-2

DOEpatents

Li, Xin-Liang; Ljungdahl, Lars G.; Chen, Huizhong; Ximenes, Eduardo A.

2001-02-06

Provided is a novel .beta.-glucosidase from Orpinomyces sp. PC2, nucleotide sequences encoding the mature protein and the precursor protein, and methods for recombinant production of this .beta.-glucosidase.

Atrazine - Background and Updates

EPA Pesticide Factsheets

Atrazine is a widely used herbicide that can be applied before and after planting to control broadleaf and grassy weeds. Atrazine is part of the triazine chemical class which includes simazine and propazine due to their common mechanism of toxicity.

Potential impacts of seasonal variation on atrazine and metolachlor persistence in andisol soil.

PubMed

Jaikaew, Piyanuch; Boulange, Julien; Thuyet, Dang Quoc; Malhat, Farag; Ishihara, Satoru; Watanabe, Hirozumi

2015-12-01

To estimate the potential effect of seasonal variation on the fate of herbicides in andisol soil, atrazine and metolachlor residues were investigated through the summer and winter seasons during 2013 and 2014 under field condition. The computed half-lives of atrazine and metolachlor in soil changed significantly through the two seasons of the trial. The half-lives were shorter in summer season with 16.0 and 23.5 days for atrazine and metolachlor, respectively. In contrast, the half-lives were longer during the winter season with 32.7 and 51.8 days for atrazine and metolachlor, respectively. The analysis of soil water balance suggested that more pesticide was lost in deeper soil layers through infiltration in summer than in winter. In addition, during the summer season, metolachlor was more likely to leach into deeper soil layer than atrazine possibly due to high water solubility of metolachlor.

The effect of chars and their water extractable organic carbon (WEOC) fractions on atrazine adsorption-desorption processes

NASA Astrophysics Data System (ADS)

Cavoski, I.; Jablonowski, N.; Burauel, P.; Miano, T.

2012-04-01

Chars are carbonaceous material produced from different type of biomass by pyrolysis. They are known as highly effective adsorbents for atrazine therefore limiting its degradation and its diffusion into the aqueous phase. The aim of the present work is to study the effects of different chars and char's derived WEOC on atrazine sorption-desorption processes. The five chars been used in this study derived from: 1) fast pyrolysis from hard wood (FP1); 2) flash pyrolysis from soft wood (FP2); 3) slow pyrolysis from deciduous wood (CC); 4) gasification from deciduous wood (GC) and 5) the market, purchased as activated charcoal standard (AC). Short-term batch equilibration tests were conducted to assess the sorption-desorption behavior of 14C-labeled atrazine on the chars, with a special focus on the desorption behavior using successive dilution method with six consecutive desorption step. Chars and their WEOC were physically and chemically characterized. Results demonstrate that biomass and pyrolysis process used to produce chars affect their physical and chemical properties, and atrazine adsorption-desorption behavior. Atrazine desorption resulted from the positive and competitive interactions between WEOC and chars surfaces. WEOC pool play important role in atrazine adsorption-desorption behavior. FP1 and FP2 with higher concentration of WEOC showed higher desorption rates, whereas GC, CC and AC with insignificant WEOC concentration strongly adsorb atrazine with low desorption rates. According to our results, when high WEOC pools chars are concerned, an increase in atrazine desorption can be observed but further studies would help in confirming the present results.

Chemical fate and transport of atrazine in soil gravel materials at agrichemical distribution facilities

USGS Publications Warehouse

Roy, W.R.; Krapac, I.G.; Chou, S.-F.J.

1999-01-01

The gravel commonly used to cover parking lots and roadways at retail agrichemical facilities may contain relatively large concentrations of pesticides that resulted from past management problems. These pesticides may threaten groundwater quality. Previous studies, however, suggested that the pesticides had not moved from the gravel in several sample profiles. Excavations at a closed facility revealed tremendous variability in pesticide distribution within the site. Pesticides were present below the gravel in two profiles, but the mechanism(s) for their movement were not clear. The objectives of this study were to investigate how the physical and chemical properties of the gravel influence the environmental fate of atrazine. All of the gravel samples collected and characterized contained atrazine and sufficient organic C to adsorb significant amounts of atrazine, thus retarding its movement through the gravel. Laboratory column leaching experiments, however, suggested that much of the atrazine should leach from the gravel within a year or two. A field-scale test plot was constructed to study how atrazine moves through the gravel under controlled conditions. Atrazine was "spilled" in the test plot. Atrazine moved from the gravel both vertically and horizontally. It appears that formulated product spilled on gravel will leach. A single discrete spill can give rise to phantom spills whose occurrence and distribution is not related to any specific pesticide-management practice. The apparent lack of atrazine leaching from gravel appeared to be a transient phenomenon and/or the result of sampling limitations in previous studies. The contaminated gravel clearly poses a risk to groundwater quality.

FOURTH SEMINAR TO THE MEMORY OF D.N. KLYSHKO: Algebraic solution of the synthesis problem for coded sequences

NASA Astrophysics Data System (ADS)

Leukhin, Anatolii N.

2005-08-01

The algebraic solution of a 'complex' problem of synthesis of phase-coded (PC) sequences with the zero level of side lobes of the cyclic autocorrelation function (ACF) is proposed. It is shown that the solution of the synthesis problem is connected with the existence of difference sets for a given code dimension. The problem of estimating the number of possible code combinations for a given code dimension is solved. It is pointed out that the problem of synthesis of PC sequences is related to the fundamental problems of discrete mathematics and, first of all, to a number of combinatorial problems, which can be solved, as the number factorisation problem, by algebraic methods by using the theory of Galois fields and groups.

Fact Sheet: Revised Draft Ambient Water Quality Criteria Document for Atrazine and Request for Scientific Views

EPA Pesticide Factsheets

Documents pertaining to Acute and Chronic Ambient Water Quality Aquatic Life Criteria for Atrazine (Freshwater and Salt Water) and revised Ecological Fate and Effects Risk Assessment for Atrazine. (Fact Sheet)

BIODEGRADATION OF ATRAZINE IN SUBSURFACE ENVIRONMENTS

EPA Science Inventory

The pesticide atrazine is frequently detected in ground water, including ground water used as drinking water. Little information is available on the fate of atrazine in the subsurface, including its biodegradability. The objectives of this study were to evaluate the biodegradabil...

The possible role of hydroxylation in the detoxification of atrazine in mature vetiver (Chrysopogon zizanioides Nash) grown in hydroponics.

PubMed

Marcacci, Sylvie; Raventon, Muriel; Ravanel, Patrick; Schwitzguébel, Jean-Paul

2005-01-01

The resistance mechanism of vetiver (Chrysopogon zizanioides) to atrazine was investigated to evaluate its potential for phytoremediation of environment contaminated with the herbicide. Plants known to metabolise atrazine rely on hydroxylation mediated by benzoxazinones, conjugation catalyzed by glutathione-S-transferases and dealkylation probably mediated by cytochromes P450. All three possibilities were explored in mature vetiver grown in hydroponics during this research project. Here we report on the chemical role of benzoxazinones in the transformation of atrazine. Fresh vetiver roots and leaves were cut to extract and study their content in benzoxazinones known to hydroxylate atrazine, such as 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA), 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and their mono- and di-glucosylated forms. Identification of benzoxazinones was performed by thin layer chromatography (TLC) and comparison of retention factors (Rf) and UV spectra with standards: although some products exhibited the same Rf as standards, UV spectra were different. Furthermore, in vitro hydroxylation of atrazine could not be detected in the presence of vetiver extracts. Finally, vetiver organs exposed to [14C]-atrazine did not produce any significant amount of hydroxylated products, such as hydroxyatrazine (HATR), hydroxy-deethylatrazine (HDEA), and hydroxy-deisopropylatrazine (HDIA). Altogether, these metabolic features suggest that hydroxylation was not a major metabolic pathway of atrazine in vetiver.

Atrazine concentrations in stream water and streambed sediment pore water in the St. Joseph and Galien River basins, Michigan and Indiana, May 2001-September 2003

USGS Publications Warehouse

Duris, Joseph W.; Reeves, Howard W.; Kiesler, James L.

2005-01-01

The U.S. Geological Survey (USGS) sampled multiple stream sites across the St. Joseph and Galien River Basins to detect and quantify the herbicide atrazine using a field enzyme-linked immunosorbent assay (ELISA) triazine test. In May 2001, July 2001, April 2002, August 2002, August 2003 and September 2003, composite samples were collected across streams at USGS streamflow-gaging stations. Concentrations and instantaneous loading for atrazine sampled in stream water throughout the St. Joseph River and Galien River Basins in Michigan and Indiana ranged from nondetection (< 0.05 part per billion (ppb)) with an associated load less than 0.001 kilogram per day (kg/d) to 6 ppb and a maximum load of 10 kg/d. Atrazine concentrations were highest in May 2001 just after the planting season. The lowest concentration was found in April 2002 just before planting. Atrazine concentrations in streambed-sediment pore water were not spatially connected with atrazine concentrations in stream-water samples. This study showed that atrazine concentrations were elevated from May to July in the St. Joseph and Galien River Basins. At many sites, concentrations exceeded the level that has been shown to feminize frog populations (0.2 ppb). There were 8 sites where concentrations exceeded 0.2 ppb atrazine in May 2001 and July 2001.

Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

PubMed

Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

2016-01-01

An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples, however, was degraded up to T4 treatments and was persistent in the T5 treatment. Probably, accumulation of this metabolite inhibited atrazine/cyanuric acid degradation by the enrichment culture in undiluted wastewater.

ATRAZINE AND REPRODUCTIVE FUNCTION: MODE AND MECHANISM OF ACTION STUDIES

EPA Science Inventory

Atrazine, a chlorotriazine herbicide, is used to control annual grasses and broadleaf weeds. In this review, we summarize our laboratory's work evaluating the neuroendocrine toxicity of atrazine (and related chlorotriazines) from an historic perspective. We provide the rationale ...

Atrazine in public water supplies and risk of ovarian cancer among postmenopausal women in the Iowa Women's Health Study.

PubMed

Inoue-Choi, Maki; Weyer, Peter J; Jones, Rena R; Booth, Benjamin J; Cantor, Kenneth P; Robien, Kim; Ward, Mary H

2016-09-01

Few studies have evaluated environmental chemical exposures in relation to ovarian cancer. We previously found an increased risk of ovarian cancer among postmenopausal women in Iowa associated with higher nitrate levels in public water supplies (PWS). However, elevated nitrate levels may reflect the presence of other agricultural chemicals, such as atrazine, one of the most commonly detected pesticides in Iowa PWS. We evaluated the association between atrazine in drinking water and incident ovarian cancer (N=145, 1986-2010) among 13 041 postmenopausal women in the Iowa Women's Health Study who used their PWS for ≥11 years as reported in 1989. Average levels of atrazine (1986-1987), nitrate-nitrogen (NO3-N, 1955-1988) and estimated levels of total trihalomethanes (TTHM, 1955-1988) from PWS monitoring data were linked to the participants' cities of residence. We computed HRs and 95% CIs by categories of the average atrazine level (not detected, ≤ or >0.37 parts per billion=median) using Cox proportional hazards regression adjusting for ovarian cancer risk factors. Atrazine was detected in water samples from 69 cities where 4155 women (32%) lived and levels were moderately correlated with NO3-N (ρ=0.35) and TTHM (ρ=0.24). Atrazine levels were not associated with ovarian cancer risk with or without adjusting for NO3-N and TTHM levels (p-trend=0.50 and 0.81, respectively). Further, there was no evidence for effect modification of the atrazine association by NO3-N or TTHM levels. In our study with low atrazine detection rates, we found no association between atrazine in PWS and postmenopausal ovarian cancer risk. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Antibody conjugated glycine doped polyaniline nanofilms as efficient biosensor for atrazine

NASA Astrophysics Data System (ADS)

Bhardwaj, Sanjeev K.; Sharma, Amit L.; Kim, Ki-Hyun; Deep, Akash

2017-12-01

Atrazine is an important member of triazine family of pesticides. The development of its detection methods gained great attention due to the potential health risks associated with its contamination in various media including water, soil, and food. The contamination of atrazine in drinking water beyond the legal permissible limit of EPA (e.g. 3 ng ml-1) may cause various damages to living organisms (e.g. heart, urinary, and limb defects). In this research, we discuss the potential significance of a highly sensitive conductometric immunosensor for sensing the atrazine pesticide. To this end, electrochemical assembly of glycine doped polyaniline (PAni) nanofilms on silicon (Si) substrate was built and modified further with anti-atrazine antibodies. The herein developed immunosensor offered highly sensitive detection of atrazine with a low detection limit of 0.07 ng ml-1. The proposed biosensor was simple in design with excellent performance in terms of its sensitivity, stability and specificity. Highlights •Glycine doped PAni nanofilms have been electropolymerized on Silicon substrates. •Functionality of the above thin films provides opportunity to develop an immunosensing platform. •Highly sensitive and specific detection of atrazine has been realized over a wide concentration range with a LOD of 0.07 ng ml-1. Novelty statement Atrazine is a widely used pesticide in the agriculture sector. It is highly recommended to develop simple biosensing systems for enabling the prospect of routine monitoring. The present research for the first time proposes the design of a glycine doped PAni based simple and highly effective biosensor for the atrazine pesticide. The doping of glycine has easily generated functional groups on the nano-PAni material for further convenient immobilization of anti-atrazine antibodies. The proposed sensor can be highlighted with advantages like ease of fabrication, use of environment friendly functionalization agent, specificity, wide linearity, and good sensitivity with enhanced viability.

Effects of environmentally relevant sub-chronic atrazine concentrations on African clawed frog (Xenopus laevis) survival, growth and male gonad development.

PubMed

Rimayi, Cornelius; Odusanya, David; Weiss, Jana M; de Boer, Jacob; Chimuka, Luke; Mbajiorgu, Felix

2018-06-01

Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg L -1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 μg L -1 atrazine exposed tadpoles (p < 0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 μg L -1 and 500 μg L -1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 μg L -1 cause significant mortality in tadpoles, while concentrations ≥200 μg L -1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine. Copyright © 2018 Elsevier B.V. All rights reserved.

DETERMINATION OF INTERFERING TRIAZINE DEGRADATION PRODUCTS BY GAS CHROMATOGRAPHY-ION TRAP MASS SPECTROMETRY

EPA Science Inventory

Deethyl atrazine (DEA), along with other triazine degradation products, has been added to the US Environmental Protection Agency's Drinking Water Contaminant Candidate List (CCL). In its gas chromatographic (GC) analysis, deethyl atrazine, a degradation product of atrazine, can ...

Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

EPA Science Inventory

Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca(2+) -montmorillonite clay surfaces.

PubMed

Belzunces, Bastien; Hoyau, Sophie; Benoit, Magali; Tarrat, Nathalie; Bessac, Fabienne

2017-01-30

Atrazine, a pesticide belonging to the s-triazine family, is one of the most employed pesticides. Due to its negative impact on the environment, it has been forbidden within the European Union since 2004 but remains abundant in soils. For these reasons, its behavior in soils and water at the atomic scale is of great interest. In this article, we have investigated, using DFT, the adsorption of atrazine onto two different clay surfaces: a pyrophyllite clay and an Mg-substituted clay named montmorillonite, with Ca 2+ compensating cations on its surface. The calculations show that the atrazine molecule is physisorbed on the pyrophyllite surface, evidencing the necessity to use dispersion-corrected computational methods. The adsorption energies of atrazine on montmorillonite are two to three times larger than on pyrophyllite, depending on the adsorption pattern. The computed adsorption energy is of about -30 kcal mol -1 for the two most stable montmorillonite-atrazine studied isomers. For these complexes, the large adsorption energy is related to the strong interaction between the chlorine atom of the atrazine molecule and one of the Ca 2+ compensating cations of the clay surface. The structural modifications induced by the adsorption are localized: for the surface, close to substitutions and particularly below the Ca 2+ cations; in the molecule, around the chlorine atom when Ca 2+ interacts strongly with this basic site in a monodentate mode. This study shows the important role of the alkaline earth cations on the adsorption of atrazine on clays, suggesting that the atrazine pesticide retention will be significant in Ca 2+ -montmorillonite clays. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Hydroxyatrazine in soils and sediments

USGS Publications Warehouse

Lerch, R.N.; Thurman, E.M.; Blanchard, P.E.

1999-01-01

Hydroxyatrazine (HA) is the major metabolite of atrazine in most surface soils. Knowledge of HA sorption to soils, and its pattern of stream water contamination suggest that it is persistent in the environment. Soils with different atrazine use histories were collected from four sites, and sediments were collected from an agricultural watershed. Samples were exhaustively extracted with a mixed-mode extractant, and HA was quantitated using high performance liquid chromatography with UV detection. Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were also measured in all samples. Concentrations of HA were considerably greater than concentrations of atrazine, DEA, and DIA in all soils and sediments studied. Soil concentrations of HA ranged from 14 to 640 ??g/kg with a median concentration of 84 ??g/kg. Sediment concentrations of HA ranged from 11 to 96 ??g/kg, with a median concentration of 14 ??g/kg. Correlations of HA and atrazine concentrations to soil properties indicated that HA levels in soils were controlled by sorption of atrazine. Because atrazine hydrolysis is known to be enhanced by sorption and pH extremes, soils with high organic matter (OM) and clay content and low pH will result in greater atrazine sorption and subsequent hydrolysis. Significant correlation of HA concentrations to OM, pH, and cation exchange capacity of sediments indicated that mixed-mode sorption (i.e., binding by cation exchange and hydrophobic interactions) was the mechanism controlling HA levels in sediment. The presence of HA in soils and stream sediments at the levels observed support existing hypotheses regarding its transport in surface runoff. These results also indicated that persistence of HA in terrestrial and aquatic ecosystems is an additional risk factor associated with atrazine usage.

Environmentally-relevant concentrations of atrazine induce non-monotonic acceleration of developmental rate and increased size at metamorphosis in Rhinella arenarum tadpoles.

PubMed

Brodeur, Julie C; Sassone, Alina; Hermida, Gladys N; Codugnello, Nadia

2013-06-01

Despite of the various studies reporting on the subject, anticipating the impacts of the widely-used herbicide atrazine on anuran tadpoles metamorphosis remains complex as increases or decreases of larval period duration are almost as frequently reported as an absence of effect. The aim of the present study was to examine the effects of environmentally-relevant concentrations of atrazine (0.1, 1, 10, 100, and 1000μg/L) on the timings of metamorphosis and body size at metamorphosis in the common South American toad, Rhinella arenarum (Anura: bufonidae). None of the atrazine concentrations tested significantly altered survival. Low atrazine concentrations in the range of 1-100μg/L were found to accelerate developmental rate in a non-monotonic U-shaped concentration-response relationship. This observed acceleration of the metamorphic process occurred entirely between stages 25 and 39; treated tadpoles proceeding through metamorphosis as control animals beyond this point. Together with proceeding through metamorphosis at a faster rate, tadpoles exposed to atrazine concentrations in the range of 1-100μg/L furthermore transformed into significantly larger metamorphs than controls, the concentration-response curve taking the form of an inverted U in this case. The no observed effect concentration (NOEC) was 0.1μg atrazine/L for both size at metamorphosis and timings of metamorphosis. Tadpoles exposed to 100μg/L 17β-estradiol presented the exact same alterations of developmental rate and body size as those treated with 1, 10 and 100μg/L of atrazine. Elements of the experimental design that facilitated the detection of alterations of metamorphosis at low concentrations of atrazine are discussed, together with the ecological significance of those findings. Copyright © 2013 Elsevier Inc. All rights reserved.

Menstrual cycle characteristics and reproductive hormone levels in women exposed to atrazine in drinking water.

PubMed

Cragin, Lori A; Kesner, James S; Bachand, Annette M; Barr, Dana Boyd; Meadows, Juliana W; Krieg, Edward F; Reif, John S

2011-11-01

Atrazine is the most commonly used herbicide in the U.S. and a wide-spread groundwater contaminant. Epidemiologic and laboratory evidence exists that atrazine disrupts reproductive health and hormone secretion. We examined the relationship between exposure to atrazine in drinking water and menstrual cycle function including reproductive hormone levels. Women 18-40 years old residing in agricultural communities where atrazine is used extensively (Illinois) and sparingly (Vermont) answered a questionnaire (n=102), maintained menstrual cycle diaries (n=67), and provided daily urine samples for analyses of luteinizing hormone (LH), and estradiol and progesterone metabolites (n=35). Markers of exposures included state of residence, atrazine and chlorotriazine concentrations in tap water, municipal water and urine, and estimated dose from water consumption. Women who lived in Illinois were more likely to report menstrual cycle length irregularity (odds ratio (OR)=4.69; 95% confidence interval (CI): 1.58-13.95) and more than 6 weeks between periods (OR=6.16; 95% CI: 1.29-29.38) than those who lived in Vermont. Consumption of >2 cups of unfiltered Illinois water daily was associated with increased risk of irregular periods (OR=5.73; 95% CI: 1.58-20.77). Estimated "dose" of atrazine and chlorotriazine from tap water was inversely related to mean mid-luteal estradiol metabolite. Atrazine "dose" from municipal concentrations was directly related to follicular phase length and inversely related to mean mid-luteal progesterone metabolite levels. We present preliminary evidence that atrazine exposure, at levels below the US EPA MCL, is associated with increased menstrual cycle irregularity, longer follicular phases, and decreased levels of menstrual cycle endocrine biomarkers of infertile ovulatory cycles. Copyright © 2011 Elsevier Inc. All rights reserved.

Simultaneous immobilization of lead and atrazine in contaminated soils using dairy-manure biochar.

PubMed

Cao, Xinde; Ma, Lena; Liang, Yuan; Gao, Bin; Harris, Willie

2011-06-01

Biochar produced from waste biomass is increasingly being recognized as a green, cost-effective amendment for environmental remediation. This work was to determine the ability of biochar to immobilize heavy metal Pb and organic pesticide atrazine in contaminated soils. Biochar prepared from dairy manure was incubated with contaminated soils at rates of 0, 2.5, and 5.0% by weight for 210 d. A commercial activated carbon (AC) was included as a comparison. The AC was effective in immobilizing atrazine, but was ineffective for Pb. However, biochar was effective in immobilizing both atrazine and Pb and the effectiveness was enhanced with increasing incubation time and biochar rates. After 210 d, soils treated with the highest rate of 5.0% biochar showed more than 57% and 66% reduction in Pb and atrazine concentrations in 0.01 M CaCl(2) extraction, respectively. Lead and atrazine concentrations in the toxicity characteristic leaching procedure solutions were reduced by 70-89% and 53-77%, respectively. Uptake of Pb and atrazine by earthworms (Eisenia fetida) was reduced by up to 79% and 73%. Phosphorus originally contained in biochar reacted with soil Pb to form insoluble hydroxypyromorphite Pb(5)(PO(4))(3)(OH), as determined by X-ray diffraction, which was presumably responsible for soil Pb immobilization, whereas atrazine stabilization may result from its adsorption by biochar demonstrated by the significant exponential decrease of extractable atrazine with increasing organic C in biochar (r(2) > 0.97, p < 0.05). The results highlighted the potential of dairy-manure biochar as a unique amendment for immobilization of both heavy metal and organic contaminants in cocontaminated soils.

Summer cover crops reduce atrazine leaching to shallow groundwater in southern Florida.

PubMed

Potter, Thomas L; Bosch, David D; Joo, Hyun; Schaffer, Bruce; Muñoz-Carpena, Rafael

2007-01-01

At Florida's southeastern tip, sweet corn (Zea Mays) is grown commercially during winter months. Most fields are treated with atrazine (6-chloro-N-ethyl-N'-[1-methylethyl]-1,3,5-triazine-2,4-diamine). Hydrogeologic conditions indicate a potential for shallow groundwater contamination. This was investigated by measuring the parent compound and three degradates--DEA (6-chloro-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine), DIA (6-chloro-N-ethyl)-1,3,5-triazine-2,4-diamine, and HA (6-hydroxy-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine)--in water samples collected beneath sweet corn plots treated annually with the herbicide. During the study, a potential mitigation measure (i.e., the use of a cover crop, Sunn Hemp [Crotalaria juncea L.], during summer fallow periods followed by chopping and turning the crop into soil before planting the next crop) was evaluated. Over 3.5 yr and production of four corn crops, groundwater monitoring indicated leaching of atrazine, DIA, and DEA, with DEA accounting for more than half of all residues in most samples. Predominance of DEA, which increased after the second atrazine application, was interpreted as an indication of rapid and extensive atrazine degradation in soil and indicated that an adapted community of atrazine degrading organisms had developed. A companion laboratory study found a sixfold increase in atrazine degradation rate in soil after three applications. Groundwater data also revealed that atrazine and degradates concentrations were significantly lower in samples collected beneath cover crop plots when compared with concentrations below fallow plots. Together, these findings demonstrated a relatively small although potentially significant risk for leaching of atrazine and its dealkylated degradates to groundwater and that the use of a cover crop like Sunn Hemp during summer months may be an effective mitigation measure.

Prediction of the fate and transport processes of atrazine in a reservoir.

PubMed

Chung, Se-Woong; Gu, Roy R

2009-07-01

The fate and transport processes of a toxic chemical such as atrazine, an herbicide, in a reservoir are significantly influenced by hydrodynamic regimes of the reservoir. The two-dimensional (2D) laterally-integrated hydrodynamics and mass transport model, CE-QUAL-W2, was enhanced by incorporating a submodel for toxic contaminants and applied to Saylorville Reservoir, Iowa. The submodel describes the physical, chemical, and biological processes and predicts unsteady vertical and longitudinal distributions of a toxic chemical. The simulation results from the enhanced 2D reservoir model were validated by measured temperatures and atrazine concentrations in the reservoir. Although a strong thermal stratification was not identified from both observed and predicted water temperatures, the spatial variation of atrazine concentrations was largely affected by seasonal flow circulation patterns in the reservoir. In particular, the results showed the effect of flow circulation on spatial distribution of atrazine during summer months as the river flow formed an underflow within the reservoir and resulted in greater concentrations near the surface of the reservoir. Atrazine concentrations in the reservoir peaked around the end of May and early June. A good agreement between predicted and observed times and magnitudes of peak concentrations was obtained. The use of time-variable decay rates of atrazine led to more accurate prediction of atrazine concentrations, while the use of a constant half-life (60 days) over the entire period resulted in a 40% overestimation of peak concentrations. The results provide a better understanding of the fate and transport of atrazine in the reservoir and information useful in the development of reservoir operation strategies with respect to timing, amount, and depth of withdrawal.

Extended fish short term reproduction assays with the fathead minnow and Japanese medaka: No evidence of impaired fecundity from exposure to atrazine.

PubMed

Brain, Richard A; Schneider, Suzanne Z; Anderson, Julie C; Knopper, Loren D; Wolf, Jeffrey C; Hanson, Mark L

2018-08-01

Short-term reproduction assays were conducted with fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes) to evaluate responses from atrazine exposure at environmentally relevant concentrations and above. Breeding groups of fish with multiple males and females were exposed to atrazine under flow-through conditions. Fathead minnows were exposed to mean measured concentrations of 1.0, 10, 26, 52, and 105 μg atrazine/L for 28 days. Medaka were exposed to mean measured concentrations of 9.4, 48, 74, 97, and 244 μg atrazine/L for 28 or 29 days. Fish were evaluated for survival, fecundity, fertility, total length, wet weight, secondary sex characteristics, gonadosomatic index (GSI) (P. promelas only), plasma or hepatic vitellogenin (VTG), and histopathology of gonads. General observations of health and behaviour were also conducted. There were no statistically significant effects (i.e., p < 0.05) of atrazine on survival, size, reproduction, behaviour, GSI, VTG, or secondary sex characteristics in either species at any exposure level. In fathead minnows, there were no histopathological findings associated with atrazine exposure in male fish, but there was an increased proportion of Stage 4.0 ovaries accompanied by an increase in proportion of Grade 3 post-ovulatory follicles in females of the 105 μg/L treatment group. Without a concomitant increase in oocyte atresia, neither of these findings are considered adverse for the health of the fish. In medaka, there were no significant effects of atrazine exposure on histopathology in either sex. These data support current weight-of-evidence assessments that atrazine does not cause direct adverse effects on fish reproduction at environmentally realistic concentrations. Copyright © 2018 Elsevier Ltd. All rights reserved.

USL/DBMS NASA/PC R and D project C programming standards

NASA Technical Reports Server (NTRS)

Dominick, Wayne D. (Editor); Moreau, Dennis R.

1984-01-01

A set of programming standards intended to promote reliability, readability, and portability of C programs written for PC research and development projects is established. These standards must be adhered to except where reasons for deviation are clearly identified and approved by the PC team. Any approved deviation from these standards must also be clearly documented in the pertinent source code.

Rice (Oryza sativa) Laccases Involved in Modification and Detoxification of Herbicides Atrazine and Isoproturon Residues in Plants.

PubMed

Huang, Meng Tian; Lu, Yi Chen; Zhang, Shuang; Luo, Fang; Yang, Hong

2016-08-24

Atrazine (ATR) and isoproturon (IPU) as herbicides have become serious environmental contaminants due to their overuse in crop production. Although ATR and IPU in soils are easily absorbed by many crops, the mechanisms for their degradation or detoxification in plants are poorly understood. This study identified a group of novel genes encoding laccases (EC 1.10.3.2) that are possibly involved in catabolism or detoxification of ATR and IPU residues in rice. Transcriptome profiling shows at least 22 differentially expressed laccase genes in ATR/IPU-exposed rice. Some of the laccase genes were validated by RT-PCR analysis. The biochemical properties of the laccases were analyzed, and their activities in rice were induced under ATR/IPU exposure. To investigate the roles of laccases in degrading or detoxifying ATR/IPU in rice, transgenic yeast cells (Pichia pastoris X-33) expressing two rice laccase genes (LOC_Os01g63180 and LOC_Os12g15680) were generated. Both transformants were found to accumulate less ATR/IPU compared to the control. The ATR/IPU-degraded products in the transformed yeast cells using UPLC-TOF-MS/MS were further characterized. Two metabolites, hydroxy-dehydrogenated atrazine (HDHA) and 2-OH-isopropyl-IPU, catalyzed by laccases were detected in the eukaryotic cells. These results indicate that the laccase-coding genes identified here could confer degradation or detoxification of the herbicides and suggest that the laccases could be one of the important enzymatic pathways responsible for ATR/IPU degradation/detoxification in rice.

LAKE MICHIGAN MASS BALANCE PROJECT: ATRAZINE MODELLING RESULTS

EPA Science Inventory

The triazine herbicide, atrazine, is used worldwide to control broadleaf and grassy weeds in agricultural regions. Atrazine is extensively used for corn crops in the midwestern US, the Great Lakes region, and in the Lake Michigan basin and has been cited as an emerging pollutant ...

Introduction of atrazine degrader to enhance rhizodegradation of atrazine

USDA-ARS?s Scientific Manuscript database

Introducing atrazine (ATR) degraders into riparian vegetative buffer strips (VBS) can be a promising bioremediation approach to accelerate the degradation of ATR and its degradation products deposited into VBS by surface runoff. A growth chamber study was conducted to investigated the synergistic ef...

DEVELOPMENTAL TOXICITY OF ATRAZINE METABOLITES IN FISCHER 344 RATS

EPA Science Inventory

Previously we have shown that atrazine, a commonly used herbicide, causes full-litter resorption (FLR) in Fischer 344 rats at 50 mg/kg. In this study, we tested four atrazine metabolites for their potential to cause FLR and developmental toxicity. Desethylatrazine (DEA), desis...

Adsorption kinetics, isotherms and thermodynamics of atrazine removal using a banana peel based sorbent.

PubMed

Chaparadza, Allen; Hossenlopp, Jeanne M

2012-01-01

Atrazine removal from water by treated banana peels was studied. The effect of pH, contact time, initial atrazine concentration, and temperature were investigated. Batch experiments demonstrated that 15 g L(-1) adsorbent dosage removed 90-99% of atrazine from 1-150 ppm aqueous solutions. The removal was both pH and temperature dependent with the most atrazine removed between pH 7 and 8.2 and increased with increasing temperature. Equilibrium data fitted well to the Langmuir and Redlich-Peterson models in the concentration and temperature ranges investigated, with a maximum adsorption capacity of 14 mg g(-1). Simple mass transfer models were applied to the experimental data to examine the adsorption mechanism and it was found that both external mass transfer and intraparticle diffusion played important roles in the adsorption mechanisms. The enthalpy of atrazine adsorption was evaluated to be 67.8 ± 6.3 kJ mol(-l) with a Gibbs free energy of -5.7 ± 1.2 kJ mol(-1).

Detoxification of Atrazine by Endophytic Streptomyces sp. Isolated from Sugarcane and Detection of Nontoxic Metabolite.

PubMed

Mesquini, Josiane A; Sawaya, Alexandra C H F; López, Begonã G C; Oliveira, Valéria M; Miyasaka, Natalia R S

2015-12-01

Atrazine is still one of the most used agricultural pesticides worldwide and it has been recognized as a major contaminant of surface and ground water. The aims of this research were to isolate an endophytic microorganism from leaves of sugarcane, evaluate its ability to degrade atrazine, and investigate the formation of metabolites. By sequencing of the 16S rRNA gene, the endophytic isolate atz2 was identified as Streptomyces sp. The reduction in atrazine concentration by Streptomyces sp. atz2 was 98 % and UHPLC-MS/MS analyses showed the appearance of an unknown metabolite observed as m/z 311. Ecotoxicity tests with an aquatic organism, Daphnia similis, confirmed that this metabolite was nontoxic. This mechanism of detoxification of atrazine is different from the ones of other free-living microorganisms that inhabit the soil or rhizosphere. The results show new aspects of atrazine detoxification, highlighting a new role of endophytic bacteria in plants.

Endocrine disruption of sexual selection by an estrogenic herbicide in the mealworm beetle (Tenebrio molitor).

PubMed

McCallum, Malcolm L; Matlock, Makensey; Treas, Justin; Safi, Barroq; Sanson, Wendy; McCallum, Jamie L

2013-12-01

The role that endocrine disruption could play in sexual selection remains relatively untested, and although estrogens occur in insects, little information exists about their biological role in insect reproduction. Atrazine is a commonly applied herbicide that mimics estrogen in vertebrates. Tenebrio molitor were raised from egg to adult under a gradation of environmentally relevant atrazine exposures and a non-treated control. Atrazine was delivered in the drinking water ad libitum. Female T. molitor were provided with a choice between unrelated males raised under three levels of atrazine exposures. Female preference for males demonstrated a non-monotonic inverted U-shaped response to atrazine exposure. There was no significant difference between the control and the high exposure to atrazine. Excluding the control, female preference increased as exposure concentration increased. These results have important repercussions for nonlethal effects of endocrine disruption on populations, their capacity to interfere with sexual selection, and the role of estrogen in pheromone communication among insects.

Gonadal development of larval male Xenopus laevis exposed to atrazine in outdoor microcosms

USGS Publications Warehouse

Jooste, A.M.; Du Preez, L.H.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Solomon, K.R.

2005-01-01

The potential effects of atrazine on gonadal development in metamorphs and subadults of the African clawed frog (Xenopus laevis) were studied under conditions of natural photoperiod and temperatures in outdoor microcosms from August 2002 to June 2003 in South Africa. Triplicate 1100 L microcosms for each nominal concentration of 0.0, 1, 10, and 25 ??g of atrazine/L were used. Measured atrazine concentrations varied <25% throughout the study, and no atrazine was detected in the control microcosms. Tadpoles developed well at all concentrations. On the basis of histological examination of testes of recently metamorphosed stage 66 frogs, 57% of the individuals in the reference group exhibited testicular oocytes as compared with 57, 59, and 39% of the 1, 10, and 25 ??g/L atrazine groups, respectively. The average prevalence of testicular oocytes for all of the treatments including the controls was 54% in a single testis, while, in 35% of individuals, testicular oocytes were observed in both testes. The number of testicular oocytes per individual ranged from 0 to 58 with means of 9.5, 9.8, 8.5, and 11.1 for the 0.0, 1, 10, and 25 ??g of atrazine/L groups, respectively. Ten months after metamorphosis, another subset of juveniles was examined, and the maximum number of testicular oocytes observed was five in one animal. The presence of testicular oocytes was not related to exposure to atrazine and may be a natural phenomenon during ontogeny. ?? 2005 American Chemical Society.

EFFECTS OF ATRAZINE ON STEROID PRODUCTION IN RAT GRANULOSA CELLS

EPA Science Inventory

Atrazine is one of the most widely used herbicides in the United States. Introduced in the 1950s, atrazine is a broad spectrum herbicide with current total annual use of approximately 76 million pounds of active ingredient. Frogs exhibit gonadal malformations and/or variations ...

EFFECTS OF ATRAZINE ON THE REPRODUCTIVE SUCCESS IN THE MARINE FISH, CUNNER(TAUTOGOLABRUS ADSPERSUS)

EPA Science Inventory

Atrazine, the most widely used herbicide in the world, leaches into ground water and surface runoff after agricultural and forestry applications. It has been detected in concentrations in the ppb range in ground water, surface waters, rivers, streams, and precipitation. Atrazin...

Identification of an atrazine-degrading benzoxazinoid in Eastern gamagrass (tripsacum dactyloides)

USDA-ARS?s Scientific Manuscript database

This study was part of a broader effort to identify and characterize promising atrazine-degrading phytochemicals in Eastern gamagrass (Tripsacum dactyloides; EG) roots for the purpose of mitigating atrazine transport from agroecosystems. The objective of this study was to isolate and identify atrazi...

PRELIMINARY OBSERVATIONS OF ATRAZINE-INDUCED EFFECTS UPON GONADAL DIFFERENTIATION IN RIVULUS MARMORATUS, A NATURALLY HERMAPHRODITIC FISH

EPA Science Inventory

The commonly used agricultural herbicide atrazine has been recognized as an endocrine disrupting chemical. In amphibians and reptiles, atrazine has been reported to alter sexual differentiation and induce secondary sexual characteristics that have been attributed to enhanced arom...

EFFECT OF ATRAZINE ON OVARIAN FUNCTION IN THE RAT

EPA Science Inventory

The effect of the chlorotriazine herbicide, atrazine, on ovarian function was studied in Long-Evans hooded (LE-hooded) and SpragucDawley (SD) rats. Atrazine was administered by gavage for 21 d to females displaying regular 4-d estrous cycles. In both sfrains, 75 mg/kg/d disrupted...

THE EFFECTS OF ATRAZINE METABOLITES ON PUBERTY IN THE MALE WISTAR RAT

EPA Science Inventory

The Effects of Atrazine Metabolites on Puberty in the Male Wistar Rat. D L Guidici, R L Cooper and T E Stoker. Endocrinology Branch, NHEERL, U.S. Environmental Protection Agency, RTP, NC.
Sponsor: R J Kavlock.
Atrazine (ATR), a chlorotriazine herbicide, alters pubertal pr...

Atrazine fate and transport within the coastal zone in southeastern Puerto Rico

USDA-ARS?s Scientific Manuscript database

Herbicide transport from crop-land to coastal waters may adversely impact water quality. This work examined potential atrazine impact from use on a farm field adjacent to the Jobos Bay National Estuarine Research Reserve on Puerto Rico’s southeastern coast. Atrazine application was linked to residu...

Introduction of Atrazine-Degrading Pseudomonas SP. Strain ADP to Enhance Phytoremediation of Atrazine

USDA-ARS?s Scientific Manuscript database

Atrazine (ATR) has been widely applied in the US Midwestern states. Public health and ecological concerns have been raised about contamination of surface and ground water by ATR and its chlorinated metabolites, due to their toxicity and potential carcinogenic or endocrinology effects. Phytoremediati...

Effects of Prenatal Exposure to a Low Dose Atrazine Metabolite Mixture on pubertal timing and prostrate Development of Male Long Evans Rats.

EPA Science Inventory

The present study examines the postnatal reproductive development of male rats following prenatal exposure to an atrazine metabolite mixture (AMM) consisting of the herbicide atrazine and its environmental metabolites diaminochlorotriazine, hydroxyatrazine, deethylatrazine, and d...

Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history

USDA-ARS?s Scientific Manuscript database

Soil bacteria on all continents except Antartica have developed the ability to rapidly degrade the herbicide atrazine, a phenomenon referred to as enhanced degradation. The agronomic significance of enhanced degradation is the potential for reduced residual weed control with atrazine in Corn, Sorgh...

Alternatives to atrazine for weed management in processing sweet corn

USDA-ARS?s Scientific Manuscript database

Atrazine has been the most widely used herbicide in North American processing sweet corn for decades; however, increased restrictions in recent years have reduced or eliminated atrazine use in certain production areas. The objective of this study was to identify the best stakeholder-derived weed man...

POTENTIAL ROLE OF TUBERO-INFUNDIBULAR DOPAMINERGIC NEURONS IN THE DISRUPTION OF PITUITARY HORMONE SECRETION BY ATRAZINE

EPA Science Inventory

Previously, we demonstrated that atrazine suppressed the ovulatory surge of luteininzing hormone and disrupted estrous cycles in the female rat. We also reported that this disruption of ovulation is likely the result of atrazine's effect on hypothalamic gonadotropin hormone rele...

ATRAZINE EFFECTS ON EARLY PREGNANCY AND IMPLANATION IN THE RAT

EPA Science Inventory

Atrazine Effects on Early Pregnancy and Implantation in the Rat.
A.M. Cummings, B.E. Rhodes*, and R.L. Cooper*.
Reproductive Toxicology Division, NHEERL, USEPA, Research Triangle Park, NC
Atrazine (ATR), an herbicide, can induce mammary tumors in rats. ATR can also sup...

GESTATIONAL ATRAZINE EXPOSURE IN THE RAT: EFFECTS ON MAMMARY GLAND DEVELOPMENT AND FUNCTION IN MULTIPLE GENERATIONS

EPA Science Inventory

The chlorotriazine herbicides currently represent the most heavily used of all agricultural pesticides, with atrazine being the most common of these chemicals. Rodent toxicology studies indicate that atrazine can disrupt endocrine function and among its effects is an increased in...

Atrazine degradation in a small stream in Iowa

USGS Publications Warehouse

Kolpin, D.W.; Kalkhoff, S.J.

1993-01-01

A study was conducted during 1990 through an 11.2-km reach of Roberts Creek in northeastern Iowa to determine the fate of atrazine in a surface water environment Water samples were collected at ~1-month intervals from April through November during stable low to medium flow conditions and analyzed for atrazine and two of its initial biotic degradation products, desethylatrazine and deisopropylatrazine. Samples were collected on the basis of a Lagrangian model of streamflow in order to sample the same parcel of water as it moved downstream. Atrazine concentrations substantially decreased (roughly 25-60%) between water entering and exiting the study reach during four of the seven sampling periods. During these same four sampling periods, the concentrations of the two biotic atrazine degradation products were constant or decreasing downstream, suggesting an abiotic degradation process.

Atrazine and increased male production by Daphnia: the importance of combining field and laboratory approaches.

PubMed

Stoeckel, James A; González, María J; Oris, James T; Kovach, Mathew J; Mace, Kimberly M

2008-11-01

Atrazine is one of the most commonly applied herbicides in North America and annually pulses through many midwestern stream and reservoir systems. Previous studies have yielded conflicting results regarding the ability of atrazine to stimulate male production by Daphnia, an effect hypothesized to lower population growth rates during a period of intense larval fish predation. In the present study, populations of Daphnia parvula and Daphnia ambigua exhibited high proportions of males but no ephippial females when atrazine pulsed into Acton Lake, a small midwestern reservoir. Field results thus supported the hypothesis of excess male production by Daphnia during the spring herbicide pulse. In laboratory studies, dose-response studies, and population-level assays revealed no effect of atrazine on male production or population growth rate of multiple clones differing in reproductive strategy and exposure history. However, D. parvula increased male production in response to an endogenous crustacean hormone (methyl farnesoate). Excess male production observed in the field population was therefore not likely caused by atrazine, although we cannot rule out the possibility of interactive effects of atrazine and some other stressor. Apparent signs of endocrine disruption in the presence of high concentrations of a suspected agent should be viewed with caution in the absence of parallel laboratory studies involving individuals from the populations of interest.

Atrazine Contamination in Water and the Impact on Amphibian Populations: A Bioassay That Measures Water Quality

NASA Astrophysics Data System (ADS)

Hayes, T. B.

2001-12-01

In recent laboratory studies, we showed that atrazine, a common herbicide, can inhibit metamorphosis, produce hermaphrodites, and inhibit male development in amphibians. In part, these effects are due to a decrease in androgen levels. These effects occur at ecologically relevant low doses (0.1 ppb), and the effective levels are below the current drinking level standard and below contaminant levels found even in rainfall in some areas. Thus, the impact of this widespread compound on free-ranging amphibians is a concern. We undertook a large-scale study to examine atrazine levels in a variety of habitats (temporary pools, rivers, lakes and ponds, and field runoff) across the US where atrazine is used and areas that report no atrazine use. Also, we collected amphibians at each site to examine them for developmental abnormalities. These ongoing studies will help determine the extent of atrazine contamination and its potential impact on amphibian populations. The concern for atrazine's impact is increased, because the mechanism through which the compound produces this effect (inhibition of androgen production) is commonly observed in fish, reptiles and mammals in addition to amphibians, although amphibians appear to sensitive at much lower doses. Thus, effects on amphibians may indicate a much broader impact.

Treatment of atrazine in nursery irrigation runoff by a constructed wetland.

PubMed

Runes, Heather B; Jenkins, Jeffrey J; Moore, James A; Bottomley, Peter J; Wilson, Bruce D

2003-02-01

To investigate the treatment capability of a surface flow wetland at a container nursery near Portland, Oregon, atrazine was introduced during simulated runoff events. Treatment efficiency was evaluated as the percent atrazine recovered (as percent of applied) in the water column at the wetland's outlet. Atrazine treatment efficiency at the outlet of the constructed wetland during a 7-d period ranged from 18-24% in 1998 (experiments 1-3) and 16-17% in 1999 (experiments 4 and 5). Changes in total flow, or frequency and intensity of runoff events did not affect treatment. For experiment 6 in 1999, where the amount, frequency, and duration of runoff events exceeded all other experiments, treatment was compromised. For all experiments, deethylatrazine (DEA) and deisopropylatrazine (DIA) accounted for 13-21% of the initial application. Hydroxyatrazine (HA) was rarely detected in the water. Organic carbon adsorption coefficients (Koc) were determined from batch equilibrium sorption isotherms with wetland sediment, and they decreased in the order of HA > DIA > atrazine > DEA. Static water-sediment column experiments indicated that sorption is an important mechanism for atrazine loss from water passing through the constructed wetland. The results of the MPN assay indicated the existence in the wetland of a low-density population of microorganisms with the potential to mineralize atrazine's ethyl side chain.

Pesticide storage and release in unsaturated soil in Illinois, USA

USGS Publications Warehouse

Roy, W.R.; Krapac, I.G.; Chou, S.-F.J.; Simmons, F.W.

2001-01-01

The chemical fate and movement of pesticides may be subject to transient storage in unsaturated soils during periods of light rainfall, and subsequent release into shallow groundwater by increased rainfall. The objective of this study was to conduct field-scale experiments to determine the relative importance of transient storage and subsequent release of agrichemicals from the vadose zone into potential aquifers. Two field-scale experiments were conducted under a rain exclusion shelter. In the 1 x experiment, atrazine and chlorpyrifos were applied at application-rate equivalents (1.6 kg ha-1 and 1.3 kg ha-1, respectively). In the 4x experiment, atrazine was applied in an amount that was four times greater than that usually applied to fields (6.7 kg ha-1). Water was either applied to simulate rain or withheld to simulate dry periods. In the 1 x experiment, atrazine was detected in the water samples whereas chlorpyrifos was not detected in the majority of the samples. The dry period imposed on the treatment plot did not appear to result in storage of the chemicals, whereas the wet period resulted in greater leaching of atrazine, although the concentrations remained less than the Maximum Contaminant Level of 3 ?? L-1. Both chemicals were detected in soil samples collected from a 20- to 30-cm depth, but it appeared that both chemicals dissipated before the field experiment was concluded. It appeared that the one-time application of atrazine and chlorpyrifos at the label rates did not result in a sufficient mass to be stored and flushed in significant concentrations to the saturated zone. When atrazine was applied at 4x and a longer drought period was imposed on the treatment plot, the resulting concentrations of dissolved atrazine were still less than 3 ??g L-1. Atrazine was detected in only the near-surface (0 to 15 cm) soil samples and the herbicide dissipated before the onset of the dry period in the treatment plot. The results of this field study demonstrated that atrazine and chlorpyrifos were not sufficiently persistent to be stored and then released in significantly large concentrations to the saturated zone. The dissipation half-life of atrazine in the 4x application was about 44 days. This study, in addition to others, suggested that atrazine may be less persistent in surface soil than has been generally reported.

Lichenase and coding sequences

DOEpatents

Li, Xin-Liang; Ljungdahl, Lars G.; Chen, Huizhong

2000-08-15

The present invention provides a fungal lichenase, i.e., an endo-1,3-1,4-.beta.-D-glucanohydrolase, its coding sequence, recombinant DNA molecules comprising the lichenase coding sequences, recombinant host cells and methods for producing same. The present lichenase is from Orpinomyces PC-2.

20 years of long-term atrazine monitoring in a shallow aquifer in western Germany.

PubMed

Vonberg, David; Vanderborght, Jan; Cremer, Nils; Pütz, Thomas; Herbst, Michael; Vereecken, Harry

2014-03-01

Atrazine was banned in Germany in 1991 due to findings of atrazine concentrations in ground- and drinking waters exceeding threshold values. Monitoring of atrazine concentrations in the groundwater since then provides information about the resilience of the groundwater quality to changing agricultural practices. In this study, we present results of a monitoring campaign of atrazine concentrations in the Zwischenscholle aquifer. This phreatic aquifer is exposed to intensive agricultural land use and susceptible to contaminants due to a shallow water table. In total 60 observation wells (OWs) have been monitored since 1991, of which 15 are sampled monthly today. Descriptive statistics of monitoring data were derived using the "regression on order statistics" (ROS) data censoring approach, estimating values for nondetects. The monitoring data shows that even 20 years after the ban of atrazine, the groundwater concentrations of sampled OWs remain on a level close to the threshold value of 0.1 μg l(-1) without any considerable decrease. The spatial distribution of atrazine concentrations is highly heterogeneous with OWs exhibiting permanently concentrations above the regulatory threshold on the one hand and OWs were concentrations are mostly below the limit of quantification (LOQ) on the other hand. A deethylatrazine-to-atrazine ratio (DAR) was used to distinguish between diffuse - and point-source contamination, with a global mean value of 0.84 indicating mainly diffuse contamination. Principle Component Analysis (PCA) of the monitoring dataset demonstrated relationships between the metabolite desisopropylatrazine, which was found to be exclusively associated with the parent compound simazine but not with atrazine, and between deethylatrazine, atrazine, nitrate, and the specific electrical conductivity. These parameters indicate agricultural impacts on groundwater quality. The findings presented in this study point at the difficulty to estimate mean concentrations of contamination for entire aquifers and to evaluate groundwater quality based on average parameters. However, analytical data of monthly sampled single observation wells provide adequate information to characterize local contamination and evolutionary trends of pollutant concentration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development a computer codes to couple PWR-GALE output and PC-CREAM input

NASA Astrophysics Data System (ADS)

Kuntjoro, S.; Budi Setiawan, M.; Nursinta Adi, W.; Deswandri; Sunaryo, G. R.

2018-02-01

Radionuclide dispersion analysis is part of an important reactor safety analysis. From the analysis it can be obtained the amount of doses received by radiation workers and communities around nuclear reactor. The radionuclide dispersion analysis under normal operating conditions is carried out using the PC-CREAM code, and it requires input data such as source term and population distribution. Input data is derived from the output of another program that is PWR-GALE and written Population Distribution data in certain format. Compiling inputs for PC-CREAM programs manually requires high accuracy, as it involves large amounts of data in certain formats and often errors in compiling inputs manually. To minimize errors in input generation, than it is make coupling program for PWR-GALE and PC-CREAM programs and a program for writing population distribution according to the PC-CREAM input format. This work was conducted to create the coupling programming between PWR-GALE output and PC-CREAM input and programming to written population data in the required formats. Programming is done by using Python programming language which has advantages of multiplatform, object-oriented and interactive. The result of this work is software for coupling data of source term and written population distribution data. So that input to PC-CREAM program can be done easily and avoid formatting errors. Programming sourceterm coupling program PWR-GALE and PC-CREAM is completed, so that the creation of PC-CREAM inputs in souceterm and distribution data can be done easily and according to the desired format.

Periphyton responses to nutrient and atrazine mixtures introduced through agricultural runoff.

PubMed

Murdock, Justin N; Shields, F Douglas; Lizotte, Richard E

2013-03-01

Agricultural runoff often contains pollutants with antagonistic impacts. The individual influence of nutrients and atrazine on periphyton has been extensively studied, but their impact when introduced together and with multiple agricultural pollutants is less clear. We simulated a field-scale runoff pulse into a riverine wetland that mimicked pollutant composition typical of field runoff of the Mississippi River Alluvial Plain. Periphyton biomass and functional responses were measured for 2 weeks along a 500 m section. Additionally, laboratory chamber assays were used to identify potential periphyton changes due to nutrients, atrazine, and their interactions. Generally, nutrients stimulated, and atrazine reduced chlorophyll a (Chl a) in chambers. In the wetland, nutrient and atrazine relationships with periphyton were weaker, and when found, were often opposite of trends in chambers. Total nitrogen (TN) was inversely related to Chl a, and total phosphorus was inversely related to respiration (R) rates. Atrazine (10-20 μg L(-1) in the wetland) had a positive relationship with ash-free dry mass (AFDM), and weakened the relationship between TN and AFDM. Wetland periphyton biomass was better correlated to total suspended solids than nutrients or atrazine. Periphyton function was resilient as periphyton gross primary production (GPP)/R ratios were not strongly impacted by runoff. However, whole-system GPP and R decreased over the 2-week period, suggesting that although periphyton metabolism recovered quickly, whole-system metabolism took longer to recover. The individual and combined impacts of nutrients and atrazine in complex pollutant mixtures can vary substantially from their influence when introduced separately, and non-linear impacts can occur with distance downstream of the pollutant introduction point.

Formation and transport of deethylatrazine in the soil and vadose zone

USGS Publications Warehouse

Adams, C.D.; Thurman, E.M.

1991-01-01

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and two degradation products were monitored at seven depths in the soil and vadose zone throughout the growing season in two experimental plots in which corn (Zea mays L.) was grown. The soils in these plots were a Kimo silty clay loam (clayey over loamy, montmorillonitic, mesic, Fluvaquentic Hapludoll) and a Eudora silt loam (course, silty, mixed, mesic, Fluventic Hapludoll). The purpose this field study was to identify and quantify the mobile and persistent degradation products of atrazine that comprise the input, or “source term,” to groundwater resulting from the application of atrazine to the soils. The formation of deethylatrazine (2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (2-amino-4-chloro-6-ethylamino-s-triazine) was monitored at vurious depths using suction lysimeters to determine the relative proportions at which these compounds enter the aquifer. Deethylatrazine was the major degradation product of atrazine identified in the soil water and appeared to enter the underlying aquifer at a concentration of 5.0 µg/L, which was greater than the concentration of atrazine entering the aquifer. Deisopropylatrazine also was detected in the soil water, bnt only in minor concentrations relative to atrazine and deethylatrazine. Because deethylatrazine was the major degradation product in the unsaturated zone, the deethylatrazine-to-atrazine ratio (DAR) may be a good indicator of transport of atrazine through the soil. The hypothesis is proposed that the DAR may be used to distinguish point-source from nonpoint-source contamination of an aquifer.

Biomarker Analysis of American Toad (Anaxyrus Americanus) and Grey Tree Frog (Hyla Versicolor) Tadpoles Following Exposure to Atrazine

EPA Science Inventory

To better understand the mode of action of atrazine in amphibians, we utilized mass spectrometry-based metabolomics to investigate the biochemical changes in two species of larval amphibians exposed to atrazine. Our objectives were to 1) Use changes in endogenous metabolites to f...

ATRAZINE ECOLOGICAL EFFECTS ASSESSMENT FOR OPP LEVEL OF CONCERN AND OW WATER QUALITY CRITERION FOR AQUATIC LIFE

EPA Science Inventory

Atrazine is a relatively water-soluble and persistent herbicide that can reach concentrations of possible ecological concern for aquatic plants in vulnerable watersheds in regions with high agricultural usage of atrazine. As a consequence, the U.S. EPA Office of Water is current...

Response of reservoir atrazine concentrations following regulatory and management changes

USDA-ARS?s Scientific Manuscript database

Since the early 1990s, atrazine concentrations in United States drinking water supplies exceeding the drinking water standard of 3 parts per billion (ppb) have been identified as a costly and major water quality concern. Atrazine levels in Columbus, Ohio tap water reached 8.74 ppb in the early 1990s...

Understanding the Effects of Atrazine on Steroidogenesis in rat granulosa and H295R adrenal cortical carcinoma cells

EPA Science Inventory

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was introduced in the 1950s as a broad spectrum herbicide, and remains one of the most widely used herbicides in the United States. Several studies have suggested that atrazine modifies steroidogenesis and may disrupt r...

THE ENDOCRINE PROFILE OF INTACT FEMALE RATS ON THE DAY OF PROESTRUS FOLLOWING EXPOSURE TO ATRAZINE

EPA Science Inventory

The Endocrine Profile of Intact Female Rats on the Day of Proestrus Following Exposure to Atrazine.
RL Cooper, A Buckalew, SC Laws and TE Stoker
Endocrinology Branch, RTD, NHEERL, ORD, U.S. EPA, RTP, NC, 27711.

The chlorotriazine herbicide, atrazine, has been sho...

Biomarker analysis of American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles following exposure to atrazine.

EPA Science Inventory

The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environme...

Simulation of branched serial first-order decay of atrazine and metabolites in adapted and nonadapted soils

USGS Publications Warehouse

Webb, R.M.; Sandstrom, M.W.; Krutz, L.J.; Shaner, D.L.

2011-01-01

In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented. ?? 2011 SETAC.

Simulation of branched serial first-order decay of atrazine and metabolites in adapted and nonadapted soils

USGS Publications Warehouse

Webb, Richard M.; Sandstrom, Mark W.; Jason L. Krutz,; Dale L. Shaner,

2011-01-01

In the present study a branched serial first-order decay (BSFOD) model is presented and used to derive transformation rates describing the decay of a common herbicide, atrazine, and its metabolites observed in unsaturated soils adapted to previous atrazine applications and in soils with no history of atrazine applications. Calibration of BSFOD models for soils throughout the country can reduce the uncertainty, relative to that of traditional models, in predicting the fate and transport of pesticides and their metabolites and thus support improved agricultural management schemes for reducing threats to the environment. Results from application of the BSFOD model to better understand the degradation of atrazine supports two previously reported conclusions: atrazine (6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine) and its primary metabolites are less persistent in adapted soils than in nonadapted soils; and hydroxyatrazine was the dominant primary metabolite in most of the soils tested. In addition, a method to simulate BSFOD in a one-dimensional solute-transport unsaturated zone model is also presented.

Photoaffinity labeling of an herbicide receptor protein in chloroplast membranes

PubMed Central

Pfister, Klaus; Steinback, Katherine E.; Gardner, Gary; Arntzen, Charles J.

1981-01-01

2-Azido-4-ethylamino-6-isopropylamino-s-triazine (azido-atrazine) inhibits photosynthetic electron transport at a site identical to that affected by atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine). The latter is a well-characterized inhibitor of photosystem II reactions. Azido-atrazine was used as a photoaffinity label to identify the herbicide receptor protein; UV irradiation of chloroplast thylakoids in the presence of azido[14C]atrazine resulted in the covalent attachment of radioactive inhibitor to thylakoid membranes isolated from pea seedlings and from a triazine-susceptible biotype of the weed Amaranthus hybridus. No covalent binding of azido-atrazine was observed for thylakoid membranes isolated from a naturally occurring triazine-resistant biotype of A. hybridus. Analysis of thylakoid polypeptides from both the susceptible and resistant A. hybridus biotypes by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, followed by fluorography to locate 14C label, demonstrated specific association of the azido[14C]atrazine with polypeptides of the 34- to 32-kilodalton size class in susceptible but not in resistant membranes. Images PMID:16592984

The impact of the herbicide atrazine on growth and photosynthesis of seagrass, Zostera marina (L.), seedlings.

PubMed

Gao, Yaping; Fang, Jianguang; Zhang, Jihong; Ren, Lihua; Mao, Yuze; Li, Bin; Zhang, Mingliang; Liu, Dinghai; Du, Meirong

2011-08-01

The impact of the widely used herbicide atrazine on seedling growth and photosynthesis of eelgrass was determined. The long-term impact of the herbicide atrazine (1, 10 and 100 μg/L) on growth of eelgrass Zostera marina (L.) seedlings, maintained in outdoor aquaria, was monitored over 4 weeks. Exposure to 10 μg/L atrazine resulted in significantly lower plant fresh weight and total chlorophyll concentration and up to 86.67% mortality at the 100 μg/L concentration. Short-term photosynthetic stress on eelgrass seedlings was determined and compared with adult eelgrass using chlorophyll fluorescence. The effective quantum yield in eelgrass seedlings was significantly depressed at all atrazine concentrations (2, 4, 8, 16, 32 and 64 μg/L) even within 2 h and remained at a lower level than for adult plants for each concentration. These results indicate that atrazine presents a potential threat to seagrass seedling functioning and that the impact is much higher than for adult plants. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Interference modelling, experimental design and pre-concentration steps in validation of the Fenton's reagent for pesticides determination.

PubMed

Ostra, Miren; Ubide, Carlos; Zuriarrain, Juan

2007-02-12

The determination of atrazine in real samples (commercial pesticide preparations and water matrices) shows how the Fenton's reagent can be used with analytical purposes when kinetic methodology and multivariate calibration methods are applied. Also, binary mixtures of atrazine-alachlor and atrazine-bentazone in pesticide preparations have been resolved. The work shows the way in which interferences and the matrix effect can be modelled. Experimental design has been used to optimize experimental conditions, including the effect of solvent (methanol) used for extraction of atrazine from the sample. The determination of pesticides in commercial preparations was accomplished without any pre-treatment of sample apart from evaporation of solvent; the calibration model was developed for concentration ranges between 0.46 and 11.6 x 10(-5) mol L(-1) with mean relative errors under 4%. Solid-phase extraction is used for pre-concentration of atrazine in water samples through C(18) disks, and the concentration range for determination was established between 4 and 115 microg L(-1) approximately. Satisfactory results for recuperation of atrazine were always obtained.

Occurrence and flux of selected pesticides in surface water of the upper snake River Basin, Idaho and western Wyoming

USGS Publications Warehouse

Clark, G.M.

1997-01-01

During May and June 1994, 37 water samples were collected at 31 sites in the upper Snake River Basin and analyzed for 83 pesticides and pesticide metabolites. EPTC, atrazine, and the atrazine metabolite deethylated atrazine were the most frequently detected and were found in 30, 20, and 13 of the samples, respectively. Fifteen additional pesticides were detected at least once. All the compounds detected were at concentrations of less than 1 microgram per liter. Total annual applications of EPTC and atrazine within subbasins and their instantaneous instream fluxes have a logarithmic relation with coefficients of determination (R2 values) of 0.55 and 0.62, respectively. At the time of sampling, the median daily flux of EPTC was about O. 0001% of the annual amount applied in a subbasin, whereas the median daily flux of atrazine was between 0.001 and 0.01%. The difference in fluxes between EPTC and atrazine probably results from differences in their physical properties and in the method and timing of application.

Parallel Computation of the Jacobian Matrix for Nonlinear Equation Solvers Using MATLAB

NASA Technical Reports Server (NTRS)

Rose, Geoffrey K.; Nguyen, Duc T.; Newman, Brett A.

2017-01-01

Demonstrating speedup for parallel code on a multicore shared memory PC can be challenging in MATLAB due to underlying parallel operations that are often opaque to the user. This can limit potential for improvement of serial code even for the so-called embarrassingly parallel applications. One such application is the computation of the Jacobian matrix inherent to most nonlinear equation solvers. Computation of this matrix represents the primary bottleneck in nonlinear solver speed such that commercial finite element (FE) and multi-body-dynamic (MBD) codes attempt to minimize computations. A timing study using MATLAB's Parallel Computing Toolbox was performed for numerical computation of the Jacobian. Several approaches for implementing parallel code were investigated while only the single program multiple data (spmd) method using composite objects provided positive results. Parallel code speedup is demonstrated but the goal of linear speedup through the addition of processors was not achieved due to PC architecture.

Phytotoxicity assessment of atrazine on growth and physiology of three emergent plants.

PubMed

Wang, Qinghai; Que, Xiaoe; Zheng, Ruilun; Pang, Zuo; Li, Cui; Xiao, Bo

2015-07-01

The emergent plants Acorus calamus, Lythrum salicaria, and Scirpus tabernaemontani were exposed to atrazine for 15, 30, 45, and 60 days in a hydroponic system. Effects were evaluated investigating plant growth, chlorophyll (Chl) content, peroxidase (POD) activity, and malondialdehyde (MDA) content. Results showed that selected plants survived in culture solution with atrazine ≤8 mg L(-1), but relative growth rates decreased significantly in the first 15-day exposure. Chla content decreased, but MDA increased with increasing atrazine concentration. S. tabernaemontani was the most insensitive species, followed by A. calamus and L.salicaria. The growth indicators exhibited significant changes in the early stage of atrazine exposure; subsequently, the negative impacts weakened and disappeared. Plant growth may be more representative of emergent plant fitness than physiological endpoints in toxicity assessment of herbicides to emergent plants.

Degradation of atrazine by microwave-assisted electrodeless discharge mercury lamp in aqueous solution.

PubMed

Ta, Na; Hong, Jun; Liu, Tingfeng; Sun, Cheng

2006-11-02

The present study investigates the degradation of atrazine (2-chloro-4-(ethyl amino)-6-isopropyl amino-s-triazine) in aqueous solution by a developed new method, namely by means of a microwave-assisted electrodeless discharge mercury lamp (MW-EDML). An experimental design was conducted to assess the influence of various parameters: pH value, initial concentration, amount of EDML, initial volume and coexisted solvent. Atrazine was degraded completely by EDML in a relatively short time (i.e. t(1/2)=1.2 min for 10 mg/l). Additionally, the identification of main degradation products during atrazine degradation process was conducted by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). This study proposes the degradation mechanism including four possible pathways for atrazine degradation according to the degradation products.

Next-Generation Sequencing of Protein-Coding and Long Non-protein-Coding RNAs in Two Types of Exosomes Derived from Human Whole Saliva.

PubMed

Ogawa, Yuko; Tsujimoto, Masafumi; Yanoshita, Ryohei

2016-01-01

Exosomes are small extracellular vesicles containing microRNAs and mRNAs that are produced by various types of cells. We previously used ultrafiltration and size-exclusion chromatography to isolate two types of human salivary exosomes (exosomes I, II) that are different in size and proteomes. We showed that salivary exosomes contain large repertoires of small RNAs. However, precise information regarding long RNAs in salivary exosomes has not been fully determined. In this study, we investigated the compositions of protein-coding RNAs (pcRNAs) and long non-protein-coding RNAs (lncRNAs) of exosome I, exosome II and whole saliva (WS) by next-generation sequencing technology. Although 11% of all RNAs were commonly detected among the three samples, the compositions of reads mapping to known RNAs were similar. The most abundant pcRNA is ribosomal RNA protein, and pcRNAs of some salivary proteins such as S100 calcium-binding protein A8 (protein S100-A8) were present in salivary exosomes. Interestingly, lncRNAs of pseudogenes (presumably, processed pseudogenes) were abundant in exosome I, exosome II and WS. Translationally controlled tumor protein gene, which plays an important role in cell proliferation, cell death and immune responses, was highly expressed as pcRNA and pseudogenes in salivary exosomes. Our results show that salivary exosomes contain various types of RNAs such as pseudogenes and small RNAs, and may mediate intercellular communication by transferring these RNAs to target cells as gene expression regulators.

Spatial variability of atrazine dissipation in an allophanic soil.

PubMed

Müller, Karin; Smith, Roger E; James, Trevor K; Holland, Patrick T; Rahman, Anis

2003-08-01

The small-scale variability (0.5 m) of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) concentrations and soil water contents in a volcanic silt loam soil (Haplic Andosol, FAO system) was studied in an area of 0.1 ha. Descriptive and spatial statistics were used to analyse the data. On average we recovered 102% of the applied atrazine 2 h after the herbicide application (CV = 35%). An increase in the CV of the concentrations with depth could be ascribed to a combination of extrinsic and intrinsic factors. Both variables, atrazine concentrations and soil water content, showed a high horizontal variability. The semivariograms of the atrazine concentrations exhibited the pure nugget effect, no pattern could be determined along the 15.5-m long transects on any of the seven sampling days over a 55-day period. Soil water content had a weak spatial autocorrelation with a range of 6-10 m. The dissipation of atrazine analysed using a high vertical sampling resolution of 0.02 m to 0.2 m showed that 70% of the applied atrazine persisted in the upper 0.02-m layer of the soil for 12 days. After 55 days and 410 mm of rainfall the centre of the pesticide mass was still at a soil depth of 0.021 m. The special characteristics of the soil (high organic carbon content, allophanic clay) had a strong influence on atrazine sorption and mobility. The mass recovery after 55 days was low. The laboratory degradation rate for atrazine, determined in a complementary incubation study and corrected for the actual field temperature using the Arrhenius equation, only accounted for about 35% of the losses that occurred in the field. Results suggest field degradation rates to be more changeable in time and much faster than under controlled conditions. Preferential flow is discussed as a component of the field transport process.

Risk of breast cancer for women living in rural areas from adult exposure to atrazine from well water in Wisconsin.

PubMed

McElroy, Jane A; Gangnon, Ronald E; Newcomb, Polly A; Kanarek, Marty S; Anderson, Henry A; Brook, Jim Vanden; Trentham-Dietz, Amy; Remington, Patrick L

2007-03-01

Research has suggested possible human health effects from low-level widespread exposure to environmental contaminants. We employed a novel exposure estimation technique using a publicly available data set to examine atrazine exposure, a suspected endocrine disruptor, in relation to breast cancer risk for women living in rural areas of Wisconsin. Incident breast cancer cases who were 20-79 years of age from 1987 to 2000 (n=3,275) and living in rural areas of Wisconsin at the time of interview were identified from Wisconsin's statewide cancer registry. Female controls of similar age and living in rural areas of Wisconsin were randomly selected from population lists (n=3,669). The addresses at diagnosis or reference year of study participants were assigned latitude/longitude coordinates (geocoded). The results from three statewide random studies of atrazine levels in well water in 1994, 1996, and 2001 were obtained from the Wisconsin Department of Agriculture, Trade, and Consumer Protection. Natural neighbor interpolation was used to estimate atrazine exposure levels separately for each of the 3 years. The mean atrazine exposure level was assigned to each participant based on her geocode. After adjustment for established breast cancer risk factors, compared to women in the lowest category of atrazine exposure (<0.15 ppb), the odds ratio of breast cancer for women exposed to atrazine concentrations of 1.0-2.9 ppb was 1.1 (95% CI 0.9-1.4). Results from this large population-based study do not suggest an increased risk of breast cancer from adult exposure to atrazine in drinking water. The possible risk for women exposed to levels of atrazine at or above statutory action levels of >or=3 ppb (OR 1.3, 95% CI 0.3-6.5) could not be ruled out due to small numbers in this category.

Association between Exposure to Endocrine Disruptors in Drinking Water and Preterm Birth, Taking Neighborhood Deprivation into Account: A Historic Cohort Study.

PubMed

Albouy-Llaty, Marion; Limousi, Frédérike; Carles, Camille; Dupuis, Antoine; Rabouan, Sylvie; Migeot, Virginie

2016-08-09

The relationship between preterm birth (PTB) and endocrine disruptor exposure in drinking-water has only occasionally been studied. The objective of this work was to investigate the relation between exposure to atrazine metabolites, or atrazine/nitrate mixtures, in drinking-water during pregnancy and prevalence of PTB neonates, while taking neighborhood deprivation into account. A historic cohort study in Deux-Sèvres, France, between 2005 and 2010 with a multiple imputation model for data of exposure to atrazine metabolites and a logistic regression were carried out. We included 13,654 mother/neonate pairs living in 279 different census districts. The prevalence of PTB was 4%. Average atrazine metabolite concentration was 0.019 ± 0.009 (0.014-0.080) µg/L and 39% of mothers lived in less deprived areas. The individual data were associated with risk of PTB. The risk of PTB when exposed to highest concentration of atrazine metabolite adjusted for confounders, was ORa 1.625 95% CI [0.975; 2.710]. Taking, or not, neighborhood deprivation into account did not change the result. Exposure to atrazine/nitrate mixtures remained non-significant. Even if we took neighborhood deprivation into account, we could not show a significant relationship between exposure to atrazine metabolites, or mixtures, in drinking-water during the second trimester of pregnancy and PTB.

Atrazine alters expression of reproductive and stress genes in the developing hypothalamus of the snapping turtle, Chelydra serpentina.

PubMed

Russart, Kathryn L G; Rhen, Turk

2016-07-29

Atrazine is an herbicide used to control broadleaf grasses and a suspected endocrine disrupting chemical. Snapping turtles lay eggs between late May and early June, which could lead to atrazine exposure via field runoff. Our goal was to determine whether a single exposure to 2ppb or 40ppb atrazine during embryogenesis could induce short- and long-term changes in gene expression within the hypothalamus of snapping turtles. We treated eggs with atrazine following sex determination and measured gene expression within the hypothalamus. We selected genes a priori for their role in the hypothalamus-pituitary-gonad or the hypothalamus-pituitary-adrenal axes of the endocrine system. We did not identify any changes in gene expression 24-h after treatment. However, at hatching AR, Kiss1R, and POMC expression was upregulated in both sexes, while expression of CYP19A1 and PDYN was increased in females. Six months after hatching, CYP19A1 and PRLH expression was increased in animals treated with 2ppb atrazine. Our study shows persistent changes in hypothalamic gene expression due to low-dose embryonic exposure to the herbicide atrazine with significant effects in both the HPG and HPA axes. Effects reported here appear to be conserved among vertebrates. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effects of environmentally relevant concentrations of atrazine on gonadal development of snapping turtles (Chelydra serpentina).

PubMed

de Solla, Shane R; Martin, Pamela A; Fernie, Kimberly J; Park, Brad J; Mayne, Gregory

2006-02-01

The herbicide atrazine has been suspected of affecting sexual development by inducing aromatase, resulting in the increased conversion of androgens to estrogens. We used snapping turtles (Chelydra serpentina), a species in which sex is dependent on the production of estrogen through aromatase activity in a temperature-dependent manner, to investigate if environmentally relevant exposures to atrazine affected gonadal development. Eggs were incubated in soil to which atrazine was applied at a typical field application rate (3.1 L/ha), 10-fold this rate (31 L/ha), and a control rate (no atrazine) for the duration of embryonic development. The incubation temperature (25 degrees C) was selected to produce only males. Although some males with testicular oocytes and females were produced in the atrazine-treated groups (3.3-3.7%) but not in the control group, no statistical differences were found among treatments. Furthermore, snapping turtle eggs collected from natural nests in a corn field were incubated at the pivotal temperature (27.5 degrees C) at which both males and females normally would be produced, and some males had oocytes in the testes (15.4%). The presence of low numbers of males with oocytes may be a natural phenomenon, and we have limited evidence to suggest that the presence of normal males with oocytes may represent a feminizing effect of atrazine. Histological examination of the thyroid gland revealed no effect on thyroid morphology.

Association between Exposure to Endocrine Disruptors in Drinking Water and Preterm Birth, Taking Neighborhood Deprivation into Account: A Historic Cohort Study

PubMed Central

Albouy-Llaty, Marion; Limousi, Frédérike; Carles, Camille; Dupuis, Antoine; Rabouan, Sylvie; Migeot, Virginie

2016-01-01

Background: The relationship between preterm birth (PTB) and endocrine disruptor exposure in drinking-water has only occasionally been studied. The objective of this work was to investigate the relation between exposure to atrazine metabolites, or atrazine/nitrate mixtures, in drinking-water during pregnancy and prevalence of PTB neonates, while taking neighborhood deprivation into account. Method: A historic cohort study in Deux-Sèvres, France, between 2005 and 2010 with a multiple imputation model for data of exposure to atrazine metabolites and a logistic regression were carried out. Results: We included 13,654 mother/neonate pairs living in 279 different census districts. The prevalence of PTB was 4%. Average atrazine metabolite concentration was 0.019 ± 0.009 (0.014–0.080) µg/L and 39% of mothers lived in less deprived areas. The individual data were associated with risk of PTB. The risk of PTB when exposed to highest concentration of atrazine metabolite adjusted for confounders, was ORa 1.625 95% CI [0.975; 2.710]. Taking, or not, neighborhood deprivation into account did not change the result. Exposure to atrazine/nitrate mixtures remained non-significant. Conclusions: Even if we took neighborhood deprivation into account, we could not show a significant relationship between exposure to atrazine metabolites, or mixtures, in drinking-water during the second trimester of pregnancy and PTB. PMID:27517943

Agrochemicals increase trematode infections in a declining amphibian species.

PubMed

Rohr, Jason R; Schotthoefer, Anna M; Raffel, Thomas R; Carrick, Hunter J; Halstead, Neal; Hoverman, Jason T; Johnson, Catherine M; Johnson, Lucinda B; Lieske, Camilla; Piwoni, Marvin D; Schoff, Patrick K; Beasley, Val R

2008-10-30

Global amphibian declines have often been attributed to disease, but ignorance of the relative importance and mode of action of potential drivers of infection has made it difficult to develop effective remediation. In a field study, here we show that the widely used herbicide, atrazine, was the best predictor (out of more than 240 plausible candidates) of the abundance of larval trematodes (parasitic flatworms) in the declining northern leopard frog Rana pipiens. The effects of atrazine were consistent across trematode taxa. The combination of atrazine and phosphate--principal agrochemicals in global corn and sorghum production--accounted for 74% of the variation in the abundance of these often debilitating larval trematodes (atrazine alone accounted for 51%). Analysis of field data supported a causal mechanism whereby both agrochemicals increase exposure and susceptibility to larval trematodes by augmenting snail intermediate hosts and suppressing amphibian immunity. A mesocosm experiment demonstrated that, relative to control tanks, atrazine tanks had immunosuppressed tadpoles, had significantly more attached algae and snails, and had tadpoles with elevated trematode loads, further supporting a causal relationship between atrazine and elevated trematode infections in amphibians. These results raise concerns about the role of atrazine and phosphate in amphibian declines, and illustrate the value of quantifying the relative importance of several possible drivers of disease risk while determining the mechanisms by which they facilitate disease emergence.

Determination of transfer rate and nature of the residue(s) in milk from {sup 14}C-atrazine cows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thalacker, F.W.; Ash, S.G.; Simoneaux, B.J.

1996-10-01

In order to determine the rate of transfer and the nature of the atrazine residues present in milk, lactating dairy cattle were treated with atrazine at three concentrations, 0.764 ppm, 0.0747 ppm and 0.0085 ppm (dry weight of food consumed). The concentrations were selected to bridge the gap between the concentration used for EPA metabolism studies (10 ppm) and the potential exposure level of dairy cattle to atrazine and its chlorotriazine metabolites through feed. The cattle were dosed following the morning milking for nine consecutive days with a single capsule bolus of {sup 14}C-atrazine. Milk was collected twice daily andmore » aliquots of each milking and the individual cow`s daily pool of milk were analyzed by liquid scinitllation counting (LSC). The concentrations of {sup 14}C-residues in the milk plateaued on approximately day 3 and the mean {sup 14}C-atrazine levels in milk were 11.2 ppb, 1.13 ppb and 0.152 ppb for the high, middle and low dosed animals, respectively. The transfer of radioactive level of exposure to {sup 14}C-atrazine. The nature of the residues in milk were determined by extracting milk samples and analysis by HPLC, TLC or Aminex chromatography. Diaminchlorotriazine was the only chlorinated metabolite in the milk, constituting approximately 65% to 75% of the total radioactive residues (TRR).« less

Prevalence of the gene trzN and biogeographic patterns among atrazine-degrading bacteria isolated from 13 Colombian agricultural soils.

PubMed

Arbeli, Ziv; Fuentes, Cilia

2010-09-01

The following study evaluated the diversity and biogeography of 83 new atrazine-degrading bacteria and the composition of their atrazine degradation genes. These strains were isolated from 13 agricultural soils and grouped according to rep-PCR genomic fingerprinting into 11 major clusters, which showed biogeographic patterns. Three clusters (54 strains) belonged to the genus Arthrobacter, seven clusters (28 strains) were similar to the genus Nocardioides and only one strain was a gram-negative from the genus Ancylobacter. PCR assays for the detection of the genes atzA, B, C, D, E, F and trzN conducted with each of the 83 strains revealed that 82 strains (all gram positive) possessed trzN, 74 of them possessed the combination of trzN, atzB and atzC, while only the gram-negative strain had atzA. A similar PCR assay for the two analogous genes, atzA and trzN, responsible for the first step of atrazine degradation, was performed with DNA extracted directly from the enrichment cultures and microcosms spiked with atrazine. In these assays, the gene trzN was detected in each culture, while atzA was detected in only six out of 13 soils. These results raise an interesting hypothesis on the evolutionary ecology of the two atrazine chlorohydrolase genes (i.e. atzA and trzN) and about the biogeography of atrazine-degrading bacteria.

DEVELOPMENT AND APPLICATION OF IMMUNOAFFINITY COLUMN CHROMATOGRAPHY AS A CLEANUP METHOD FOR THE DETERMINATION OF ATRAZINE IN COMPLEX ENVIRONMENTAL SAMPLE MEDIA

EPA Science Inventory

A rabbit antibody immunoaffinity (IA) column procedure was evaluated as a cleanup method for the determination of atrazine in soil, sediment, and food. Four IA columns were prepared by immobilizing a polyclonal rabbit anti-atrazine antibody solution to HiTrap Sepharose columns. A...

Characterization of Atrazine-Induced Gonadal Malformations in African Clawed Frogs (Xenopus laevis) and Comparisons with Effects of an Androgen Antagonist (Cyproterone Acetate) and Exogenous Estrogen (17β-Estradiol): Support for the Demasculinization/Feminization Hypothesis

PubMed Central

Hayes, Tyrone B.; Stuart, A. Ali; Mendoza, Magdalena; Collins, Atif; Noriega, Nigel; Vonk, Aaron; Johnston, Gwynne; Liu, Roger; Kpodzo, Dzifa

2006-01-01

Atrazine is a potent endocrine disruptor that both chemically castrates and feminizes male amphibians. It depletes androgens in adult frogs and reduces androgen-dependent growth of the larynx in developing male larvae. It also disrupts normal gonadal development and feminizes the gonads of developing males. Gonadal malformations induced by atrazine include hermaphrodites and males with multiple testes [single sex polygonadism (SSP)], and effects occur at concentrations as low as 0.1 ppb (μg/L). Here, we describe the frequencies at which these malformations occur and compare them with morphologies induced by the estrogen, 17β-estradiol (E2), and the antiandrogen cyproterone acetate, as a first step in testing the hypothesis that the effects of atrazine are a combination of demasculinization and feminization. The various forms of hermaphroditism did not occur in controls. Nonpigmented ovaries, which occurred at relatively high frequencies in atrazine-treated larvae, were found in four individuals out of more than 400 controls examined (1%). Further, we show that several types of gonadal malformations (SSP and three forms of hermaphroditism) are produced by E2 exposure during gonadal differentiation, whereas a final morphology (nonpigmented ovaries) appears to be the result of chemical castration (disruption of androgen synthesis and/or activity) by atrazine. These experimental findings suggest that atrazine-induced gonadal malformations result from the depletion of androgens and production of estrogens, perhaps subsequent to the induction of aromatase by atrazine, a mechanism established in fish, amphibians, reptiles, and mammals (rodents and humans). PMID:16818259

In vitro atrazine-exposure inhibits human natural killer cell lytic granule release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Alexander M.; Brundage, Kathleen M.; Center for Immunopathology and Microbial Pathogenesis, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506

2007-06-01

The herbicide atrazine is a known immunotoxicant and an inhibitor of human natural killer (NK) cell lytic function. The precise changes in NK cell lytic function following atrazine exposure have not been fully elucidated. The current study identifies the point at which atrazine exerts its affect on the stepwise process of human NK cell-mediated lyses of the K562 target cell line. Using intracellular staining of human peripheral blood lymphocytes, it was determined that a 24-h in vitro exposure to atrazine did not decrease the level of NK cell lytic proteins granzyme A, granzyme B or perforin. Thus, it was hypothesizedmore » that atrazine exposure was inhibiting the ability of the NK cells to bind to the target cell and subsequently inhibit the release of lytic protein from the NK cell. To test this hypothesis, flow cytometry and fluorescent microscopy were employed to analyze NK cell-target cell co-cultures following atrazine exposure. These assays demonstrated no significant decrease in the level of target cell binding. However, the levels of NK intracellular lytic protein retained and the amount of lytic protein released were assessed following a 4-h incubation with K562 target cells. The relative level of intracellular lytic protein was 25-50% higher, and the amount of lytic protein released was 55-65% less in atrazine-treated cells than vehicle-treated cells following incubation with the target cells. These results indicate that ATR exposure inhibits the ability of NK cells to lyse target cells by blocking lytic granule release without affecting the ability of the NK cell to form stable conjugates with target cells.« less

Effects of nitrate and atrazine on larval development and sexual differentiation in the northern leopard frog Rana pipiens.

PubMed

Orton, Frances; Carr, James A; Handy, Richard D

2006-01-01

Pollution from agrochemicals may be contributing to the global decline in amphibian populations. Environmentally relevant concentrations of nitrate and/or atrazine on anuran development and gonadal differentiation were tested. Four replicates of 20 tadpoles per tank (80/treatment) were exposed from Taylor-Kollros stage 2 to 3 to stage 23 to 34 to either 10 mg/L nitrate, 10 microg/L atrazine, a combined exposure of 10 mg/L nitrate plus 10 microg/L atrazine, or untreated controls. No treatment-dependent effects on weight, snout-vent or hind limb length, or time to forelimb emergence were observed. The proportions of females increased in all treatments compared to the controls, especially in the combined treatment (chi2 = 17.90, df = 6, p = 0.0065, combined = 66.4% female, control = 41% female). The frequency of intersex was low in all treatments. No treatment-related effects on the total number of spermatogenic cells were observed, but the ratio of cell types differed in that testes from animals in the treated groups exhibited more spermatogonia, fewer spermatocytes, and more spermatids than the control (significantly different, Kruskal-Wallis, p < 0.05). Ovaries from animals treated with nitrate or atrazine exhibited larger immature (previtellogenic) and mature (vitellogenic) follicles, but ovaries from the combined treatment had larger immature follicles only. Testicular oocytes were observed in the nitrate-only and atrazine-only treatments, and the control treatment, but not the combined treatment. Overall, this study has demonstrated changes in sex ratios that are more marked in response to combined nitrate/atrazine exposure than with these chemicals alone. Histological evidence suggests that premature maturation of gonad may occur as a result of nitrate and/or atrazine exposure during larval development.

Simulation with EGS4 code of external beam of radiotherapy apparatus with workstation and PC gives similar results?

PubMed

Malataras, G; Kappas, C; Lovelock, D M; Mohan, R

1997-01-01

This article presents a comparison between two implementations of an EGS4 Monte Carlo simulation of a radiation therapy machine. The first implementation was run on a high performance RISC workstation, and the second was run on an inexpensive PC. The simulation was performed using the MCRAD user code. The photon energy spectra, as measured at a plane transverse to the beam direction and containing the isocenter, were compared. The photons were also binned radially in order to compare the variation of the spectra with radius. With 500,000 photons recorded in each of the two simulations, the running times were 48 h and 116 h for the workstation and the PC, respectively. No significant statistical differences between the two implementations were found.

Molecularly imprinted polymer for analysis of trace atrazine herbicide in water.

PubMed

Kueseng, Pamornrat; Noir, Mathieu L; Mattiasson, Bo; Thavarungkul, Panote; Kanatharana, Proespichaya

2009-11-01

A molecularly imprinted polymer (MIP) for atrazine was synthesized by non-covalent method. The binding capacity of MIP was 1.00 mg g(-1) polymer. The selectivity and recovery were investigated with various pesticides which are mostly, found in the environment, for both similar and different chemical structure of atrazine. The competitive recognition between atrazine and structurally similar compounds was evaluated and it was found that the system provided highest recovery and selectivity for atrazine while low recovery and selectivity were obtained for the other compounds. The highest recovery was obtained from MIP compared with non-imprinted polymer (NIP), a commercial C(18) and a granular activated carbon (GAC) sorbent. The method provided high recoveries ranged from 94 to 99% at two spiked levels with relative standard deviations less than 2%. The lower detection limit of the method was 80 ng L(-1). This method was successfully applied for analysis of environmental water samples.

THE EFFECTS OF ATRAZINE METABOLITES ON PUBERTY AND THYROID FUNCTION IN THE MALE WISTAR RATS: AN EVALUATION IN THE MALE PUBERTAL PROTOCOL

EPA Science Inventory

The Effects of Atrazine Metabolites on Puberty in the Male Wistar Rat. D L Guidici, R L Cooper and T E Stoker. Endocrinology Branch, NHEERL, U.S. Environmental Protection Agency, RTP, NC.
Sponsor: R J Kavlock.
Atrazine (ATR), a chlorotriazine herbicide, alters pubertal pr...

Model Forecasts of Atrazine in Lake Michigan in Response to Various Sensitivity and Potential Management Scenarios

EPA Science Inventory

For more than forty years, the herbicide atrazine has been used on corn crops in the Lake Michigan basin to control weeds. It is usually applied to farm fields in the spring before or after the corn crop emerges. A version of the WASP4 mass balance model, LM2-Atrazine, was used...

DISTRIBUTION OF 14C-ATRAZINE FOLLOWING AN ACUTE LACTATIONAL EXPOSURE IN THE WISTAR RAT.

EPA Science Inventory

The purpose of the present study was to examine the distribution of atrazine in the lactating dam and suckling neonate following an acute exposure to either 2 or 4 mg/kg 14C-atrazine (14C-ATR) by gavage. 14C-ATR was administered to the nursing dam on postnatal day 3 by oral gavag...

Watershed regressions for pesticides (warp) models for predicting atrazine concentrations in Corn Belt streams

USGS Publications Warehouse

Stone, Wesley W.; Gilliom, Robert J.

2012-01-01

Watershed Regressions for Pesticides (WARP) models, previously developed for atrazine at the national scale, are improved for application to the United States (U.S.) Corn Belt region by developing region-specific models that include watershed characteristics that are influential in predicting atrazine concentration statistics within the Corn Belt. WARP models for the Corn Belt (WARP-CB) were developed for annual maximum moving-average (14-, 21-, 30-, 60-, and 90-day durations) and annual 95th-percentile atrazine concentrations in streams of the Corn Belt region. The WARP-CB models accounted for 53 to 62% of the variability in the various concentration statistics among the model-development sites. Model predictions were within a factor of 5 of the observed concentration statistic for over 90% of the model-development sites. The WARP-CB residuals and uncertainty are lower than those of the National WARP model for the same sites. Although atrazine-use intensity is the most important explanatory variable in the National WARP models, it is not a significant variable in the WARP-CB models. The WARP-CB models provide improved predictions for Corn Belt streams draining watersheds with atrazine-use intensities of 17 kg/km2 of watershed area or greater.

Characterization of atrazine binding to dissolved organic matter of soil under different types of land use.

PubMed

Zhu, Long-Ji; Zhao, Yue; Chen, Yan-Ni; Cui, Hong-Yang; Wei, Yu-Quan; Liu, Hai-Long; Chen, Xiao-Meng; Wei, Zi-Min

2018-01-01

Atrazine is widely used in agriculture. In this study, dissolved organic matter (DOM) from soils under four types of land use (forest (F), meadow (M), cropland (C) and wetland (W)) was used to investigate the binding characteristics of atrazine. Fluorescence excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis, two-dimensional correlation spectroscopy (2D-COS) and Stern-Volmer model were combined to explore the complexation between DOM and atrazine. The EEM-PARAFAC indicated that DOM from different sources had different structures, and humic-like components had more obvious quenching effects than protein-like components. The Stern-Volmer model combined with correlation analysis showed that log K values of PARAFAC components had a significant correlation with the humification of DOM, especially for C3 component, and they were all in the same order as follows: meadow soil (5.68)>wetland soil (5.44)>cropland soil (5.35)>forest soil (5.04). The 2D-COS further confirmed that humic-like components firstly combined with atrazine followed by protein-like components. These findings suggest that DOM components can significantly influence the bioavailability, mobility and migration of atrazine in different land uses. Copyright © 2016 Elsevier Inc. All rights reserved.

Validation of Living Donor Nephrectomy Codes

PubMed Central

Lam, Ngan N.; Lentine, Krista L.; Klarenbach, Scott; Sood, Manish M.; Kuwornu, Paul J.; Naylor, Kyla L.; Knoll, Gregory A.; Kim, S. Joseph; Young, Ann; Garg, Amit X.

2018-01-01

Background: Use of administrative data for outcomes assessment in living kidney donors is increasing given the rarity of complications and challenges with loss to follow-up. Objective: To assess the validity of living donor nephrectomy in health care administrative databases compared with the reference standard of manual chart review. Design: Retrospective cohort study. Setting: 5 major transplant centers in Ontario, Canada. Patients: Living kidney donors between 2003 and 2010. Measurements: Sensitivity and positive predictive value (PPV). Methods: Using administrative databases, we conducted a retrospective study to determine the validity of diagnostic and procedural codes for living donor nephrectomies. The reference standard was living donor nephrectomies identified through the province’s tissue and organ procurement agency, with verification by manual chart review. Operating characteristics (sensitivity and PPV) of various algorithms using diagnostic, procedural, and physician billing codes were calculated. Results: During the study period, there were a total of 1199 living donor nephrectomies. Overall, the best algorithm for identifying living kidney donors was the presence of 1 diagnostic code for kidney donor (ICD-10 Z52.4) and 1 procedural code for kidney procurement/excision (1PC58, 1PC89, 1PC91). Compared with the reference standard, this algorithm had a sensitivity of 97% and a PPV of 90%. The diagnostic and procedural codes performed better than the physician billing codes (sensitivity 60%, PPV 78%). Limitations: The donor chart review and validation study was performed in Ontario and may not be generalizable to other regions. Conclusions: An algorithm consisting of 1 diagnostic and 1 procedural code can be reliably used to conduct health services research that requires the accurate determination of living kidney donors at the population level. PMID:29662679

Concentrations and transport of atrazine in the Delaware River-Perry Lake system, northeast Kansas, July 1993 through September 1995

USGS Publications Warehouse

Pope, L.M.; Brewer, L.D.; Foley, G.A.; Morgan, S.C.

1996-01-01

A study of the distribution and transport of atrazine in surface water in the 1,117 square-mile Delaware River Basin in northeast Kansas was conducted from July 1992 through September 1995. The purpose of this report is to present information to assess the present (1992-95) conditions and possible future changes in the distribution and magnitude of atrazine concentrations, loads, and yields spatially, temporally, and in relation to hydrologic conditions and land-use characteristics. A network of 11 stream-monitoring and sample-collection sites was established within the basin. Stream- water samples were collected during a wide range of hydrologic conditions throughout the study. Nearly 5,000 samples were analyzed by enzyme- linked immunosorbent assay (ELISA) for triazine herbicide concentrations. Daily mean triazine herbicide concentrations were calculated for all sampling sites and subsequently used to estimate daily mean atrazine concentrations with a linear- regression relation between ELISA-derived triazine concentrations and atrazine concentrations determined by gas chromatography/mass spectrometry for 141 dual-analyzed surface-water samples. During May, June, and July, time-weighted, daily mean atrazine concentrations in streams in the Delaware River Basin commonly exceeded the value of 3.0-ug/L (micrograms per liter) annual mean Maximum Contaminant Level (MCL) established by the U.S. Environmental Protection Agency for drinking-water supplies. Time-weighted, daily mean concentrations equal to or greater than 20 ug/L were not uncommon. However, most time- weighted, daily mean concentrations were less than 1.0 ug/L from August through April. The largest time-weighted, monthly mean atrazine concentrations occurred during May, June, and July. Most monthly mean concentrations between August and April were less than 0.50 ug/L. Large differences were documented in monthly mean concentrations within the basin. Sites receiving runoff from the northern and northeastern parts of the Delaware River Basin had the largest monthly and annual mean atrazine concentrations. Time- weighted, annual mean atrazine concentrations did not exceed the MCL in water from any sampling site for either the 1993 or 1994 crop years (April-March); however, concentrations were during 1994 than during 1993. Time-weighted, annual mean concentrations in water from among the 11 sampling sites during the 1993 crop year ranged from 0.27 to 1.5 ug/L and from 0.36 to 2.8 ug/L during the 1994 crop year. Furthermore, concentrations in samples from the outflow of Perry Lake were larger during the first 6 months of the 1995 crop year than during the previous year. Flow-weighted, annual mean atrazine concentrations were larger than time-weighted, annual mean concentrations in water from all sampling sites upstream of Perry Lake, and samples from several sites had concentrations were substantially larger than the MCL. This difference explained why time-weighted, annual mean concentrations in the outflow of Perry Lake were larger than corresponding time-weighted concentrations in water from sampling sites upstream of Perry Lake. Flow- weighted, annual mean concentrations in water from among the 11 sampling sites during the 1993 crop year ranged from 1.0 to 4.4 ug/L and from 1.0 to 8.9 ug/L during the 1994 crop year. Statistically significant linear-regression equations were identified relating the percentage of subbasin in cropland to time- and flow-weighted, average annual mean atrazine concentrations. The relations indicate that time-weighted, average annual mean atrazine concentrations may not exceed the MCL in water from subbasins with at least about 70-percent cropland. However, flow-weighted, average annual mean atrazine concentrations may exceed the MCL when the percentage of cropland is greater than about 40 percent. Approximately 90 percent of the annual atrazine load is transport from May through July. Atrazine loads and yields were larger during the 1993 cro

Vulnerability of ground water to atrazine leaching in Kent County, Michigan

USGS Publications Warehouse

Holtschlag, D.J.; Luukkonen, C.L.

1997-01-01

A steady-state model of pesticide leaching through the unsaturated zone was used with readily available hydrologic, lithologic, and pesticide characteristics to estimate the vulnerability of the near-surface aquifer to atrazine contamination from non-point sources in Kent County, Michigan. The modelcomputed fraction of atrazine remaining at the water table, RM, was used as the vulnerability criterion; time of travel to the water table also was computed. Model results indicate that the average fraction of atrazine remaining at the water table was 0.039 percent; the fraction ranged from 0 to 3.6 percent. Time of travel of atrazine from the soil surface to the water table averaged 17.7 years and ranged from 2.2 to 118 years.Three maps were generated to present three views of the same atrazine vulnerability characteristics using different metrics (nonlinear transformations of the computed fractions remaining). The metrics were chosen because of the highly (right) skewed distribution of computed fractions. The first metric, rm = RMλ (where λ was 0.0625), depicts a relatively uniform distribution of vulnerability across the county with localized areas of high and low vulnerability visible. The second metric, rmλ-0.5, depicts about one-half the county at low vulnerability with discontinuous patterns of high vulnerability evident. In the third metric, rmλ-1.0 (RM), more than 95 percent of the county appears to have low vulnerability; small, distinct areas of high vulnerability are present.Aquifer vulnerability estimates in the RM metric were used with a steady-state, uniform atrazine application rate to compute a potential concentration of atrazine in leachate reaching the water table. The average estimated potential atrazine concentration in leachate at the water table was 0.16 μg/L (micrograms per liter) in the model area; estimated potential concentrations ranged from 0 to 26 μg/L. About 2 percent of the model area had estimated potential atrazine concentrations in leachate at the water table that exceeded the USEPA (U.S. Environmental Protection Agency) maximum contaminant level of 3 μg/L.Uncertainty analyses were used to assess effects of parameter uncertainty and spatial interpolation error on the variability of the estimated fractions of atrazine remaining at the water table. Results of Monte Carlo simulations indicate that parameter uncertainty is associated with a standard error of 0.0875 in the computed fractions (in the rm metric). Results of kriging analysis indicate that errors in spatial interpolation are associated with a standard error of 0.146 (in the rm metric). Thus, uncertainty in fractions remaining is primarily associated with spatial interpolation error, which can be reduced by increasing the density of points where the leaching model is applied.A sensitivity analysis indicated which of 13 hydrologic, lithologic, and pesticide characteristics were influential in determining fractions of atrazine remaining at the water table. Results indicate that fractions remaining are most sensitive to the unit changes in pesticide half life and in organic-carbon content in soils and unweathered rocks, and least sensitive to infiltration rates.The leaching model applied in this report provides an estimate of the vulnerability of the near-surface aquifer in Kent County to contamination by atrazine. The vulnerability estimate is related to water-quality criteria developed by the USEPA to help assess potential risks from atrazine to the near-surface aquifer. However, atrazine accounts for only 28 percent of the herbicide use in the county; additional potential for contamination exists from other pesticides and pesticide metabolites. Therefore, additional work is needed to develop a comprehensive understanding of the relative risks associated with specific pesticides. The modeling approach described in this report provides a technique for estimating relative vulnerabilities to specific pesticides and for helping to assess potential risks.

Characterisation of an efficient atrazine-degrading bacterium, Arthrobacter sp. ZXY-2: an attempt to lay the foundation for potential bioaugmentation applications.

PubMed

Zhao, Xinyue; Wang, Li; Ma, Fang; Yang, Jixian

2018-01-01

The isolation of atrazine-degrading microorganisms with specific characteristics is fundamental for bioaugmenting the treatment of wastewater containing atrazine. However, studies describing the specific features of such microorganisms are limited, and further investigation is needed to improve our understanding of bioaugmentation. In this study, strain Arthrobacter sp. ZXY-2, which displayed a strong capacity to degrade atrazine, was isolated and shown to be a potential candidate for bioaugmentation. The factors associated with the biodegrading capacity of strain ZXY-2 were investigated, and how these factors likely govern the metabolic characteristics that control bioaugmentation functionality was determined. The growth pattern of Arthrobacter sp. ZXY-2 followed the Haldane-Andrews model with an inhibition constant ( K i ) of 52.76 mg L -1 , indicating the possible augmentation of wastewater treatment with relatively high atrazine concentrations (> 50 ppm). Real-time quantitative PCR (RT-qPCR) results showed a positive correlation between the atrazine degradation rate and the expression levels of three functional genes ( trzN , atzB , and atzC ), which helped elucidate the role of strain ZXY-2 in bioaugmentation. In addition, multiple copies of the atzB gene were putatively identified, explaining the higher expression levels of this gene than those of the other functional genes. Multiple copies of the atzB gene may represent a compensatory mechanism that ensures the biodegradation of atrazine, a feature that should be exploited in future bioaugmentation applications.

Modification of Herbicide Binding to Photosystem II in Two Biotypes of Senecio vulgaris L

PubMed Central

Pfister, Klaus; Radosevich, Steven R.; Arntzen, Charles J.

1979-01-01

The present study compares the binding and inhibitory activity of two photosystem II inhibitors: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron [DCMU]) and 2-chloro-4-(ethylamine)-6-(isopropyl amine)-S-triazene (atrazine). Chloroplasts isolated from naturally occurring triazine-susceptible and triazine-resistant biotypes of common groundsel (Senecio vulgaris L.) showed the following characteristics. (a) Diuron strongly inhibited photosynthetic electron transport from H2O to 2,6-dichlorophenolindophenol in both biotypes. Strong inhibition by atrazine was observed only with the susceptible chloroplasts. (b) Hill plots of electron transport inhibition data indicate a noncooperative binding of one inhibitor molecule at the site of action for both diuron and atrazine. (c) Susceptible chloroplasts show a strong diuron and atrazine binding (14C-radiolabel assays) with binding constants (K) of 1.4 × 10−8 molar and 4 × 10−8 molar, respectively. In the resistant chloroplasts the diuron binding was slightly decreased (K = 5 × 10−8 molar), whereas no specific atrazine binding was detected. (d) In susceptible chloroplasts, competitive binding between radioactively labeled diuron and non-labeled atrazine was observed. This competition was absent in the resistant chloroplasts. We conclude that triazine resistance of both intact plants and isolated chloroplasts of Senecio vulgaris L. is based upon a minor modification of the protein in the photosystem II complex which is responsible for herbicide binding. This change results in a specific loss of atrazine (triazine)-binding capacity. PMID:16661120

Atrazine exposure in public drinking water and preterm birth.

PubMed

Rinsky, Jessica L; Hopenhayn, Claudia; Golla, Vijay; Browning, Steve; Bush, Heather M

2012-01-01

Approximately 13% of all births occur prior to 37 weeks gestation in the U.S. Some established risk factors exist for preterm birth, but the etiology remains largely unknown. Recent studies have suggested an association with environmental exposures. We examined the relationship between preterm birth and exposure to a commonly used herbicide, atrazine, in drinking water. We reviewed Kentucky birth certificate data for 2004-2006 to collect duration of pregnancy and other individual-level covariates. We assessed existing data sources for atrazine levels in public drinking water for the years 2000-2008, classifying maternal county of residence into three atrazine exposure groups. We used logistic regression to analyze the relationship between atrazine exposure and preterm birth, controlling for maternal age, race/ethnicity, education, smoking, and prenatal care. An increase in the odds of preterm birth was found for women residing in the counties included in the highest atrazine exposure group compared with women residing in counties in the lowest exposure group, while controlling for covariates. Analyses using the three exposure assessment approaches produced odds ratios ranging from 1.20 (95% confidence interval [CI] 1.14, 1.27) to 1.26 (95% CI 1.19, 1.32), for the highest compared with the lowest exposure group. Suboptimal characterization of environmental exposure and variables of interest limited the analytical options of this study. Still, our findings suggest a positive association between atrazine and preterm birth, and illustrate the need for an improved assessment of environmental exposures to accurately address this important public health issue.

Evaluation of potential mechanisms of atrazine-induced reproductive impairment in fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes)

USGS Publications Warehouse

Richter, Cathy; Papoulias, Diana M.; Whyte, Jeffrey J.; Tillitt, Donald E.

2016-01-01

Atrazine has been implicated in reproductive dysfunction of exposed organisms, and previous studies documented decreased egg production in Japanese medaka (Oryzias latipes) and fathead minnows (Pimephales promelas) during 30-d to 38-d exposures to 0.5 µg/L, 5 µg/L, and 50 µg/L atrazine. The authors evaluated possible mechanisms underlying the reduction in egg production. Gene expression in steroidogenesis pathways and the hypothalamus–pituitary–gonad axis of male and female fish was measured. Atrazine did not significantly induce gonad aromatase (cyp19a1a) expression. An atrazine-induced shift in the number of females in an active reproductive state was observed. Expression of the egg maturation genes vitellogenin 1 (vtg1) and zona pellucida glycoprotein 3.1 (zp3.1) in medaka females was correlated and had a bimodal distribution. In both species, females with low vtg1 or zp3.1 expression also had low expression of steroidogenesis genes in the gonad, estrogen receptor in the liver, and gonadotropins in the brain. In the medaka, the number of females per tank that had high expression of zp3.1 was significantly correlated with egg production per tank. The number of medaka females with low expression of zp3.1 increased significantly with atrazine exposure. Thus, the decline in egg production observed in response to atrazine exposure may be the result of a coordinated downregulation of genes required for reproduction in a subset of females.

Estimating Supplies Program: Evaluation Report

DTIC Science & Technology

2002-12-24

Inhalation, Non-vaccinated1, Incubating, Asymptomatic 352 Anthrax, Inhalation, Non-vaccinated, Prodromal 353 Anthrax, Inhalation, Non-vaccinated, Acute...B-11 PC Code PC Description 354 Anthrax, Inhalation, Vaccinated, Asymptomatic 355 Anthrax, Inhalation, Vaccinated, Prodromal 356...Anthrax, Inhalation, Vaccinated, Acute 357 Plague, Inhalation, Incubating, Asymptomatic 358 Plague, Inhalation, Acute 359 Plague Meningitis 360

Rotordynamics on the PC: Further Capabilities of ARDS

NASA Technical Reports Server (NTRS)

Fleming, David P.

1997-01-01

Rotordynamics codes for personal computers are now becoming available. One of the most capable codes is Analysis of RotorDynamic Systems (ARDS) which uses the component mode synthesis method to analyze a system of up to 5 rotating shafts. ARDS was originally written for a mainframe computer but has been successfully ported to a PC; its basic capabilities for steady-state and transient analysis were reported in an earlier paper. Additional functions have now been added to the PC version of ARDS. These functions include: 1) Estimation of the peak response following blade loss without resorting to a full transient analysis; 2) Calculation of response sensitivity to input parameters; 3) Formulation of optimum rotor and damper designs to place critical speeds in desirable ranges or minimize bearing loads; 4) Production of Poincard plots so the presence of chaotic motion can be ascertained. ARDS produces printed and plotted output. The executable code uses the full array sizes of the mainframe version and fits on a high density floppy disc. Examples of all program capabilities are presented and discussed.

Effects of tillage and application rate on atrazine transport to subsurface drainage: Evaluation of RZWQM using a six-year field study

USGS Publications Warehouse

Malone, Robert W.; Nolan, Bernard T.; Ma, Liwang; Kanwar, Rameshwar S.; Pederson, Carl H.; Heilman, Philip

2014-01-01

Well tested agricultural system models can improve our understanding of the water quality effects of management practices under different conditions. The Root Zone Water Quality Model (RZWQM) has been tested under a variety of conditions. However, the current model's ability to simulate pesticide transport to subsurface drain flow over a long term period under different tillage systems and application rates is not clear. Therefore, we calibrated and tested RZWQM using six years of data from Nashua, Iowa. In this experiment, atrazine was spring applied at 2.8 (1990–1992) and 0.6 kg/ha/yr (1993–1995) to two 0.4 ha plots with different tillage (till and no-till). The observed and simulated average annual flow weighted atrazine concentrations (FWAC) in subsurface drain flow from the no-till plot were 3.7 and 3.2 μg/L, respectively for the period with high atrazine application rates, and 0.8 and 0.9 μg/L, respectively for the period with low application rates. The 1990–1992 observed average annual FWAC difference between the no-till and tilled plot was 2.4 μg/L while the simulated difference was 2.1 μg/L. These observed and simulated differences for 1993–1995 were 0.1 and 0.1 μg/L, respectively. The Nash–Sutcliffe model performance statistic (EF) for cumulative atrazine flux to subsurface drain flow was 0.93 for the no-till plot testing years (1993–1995), which is comparable to other recent model tests. The value of EF is 1.0 when simulated data perfectly match observed data. The order of selected parameter sensitivity for RZWQM simulated FWAC was atrazine partition coefficient > number of macropores > atrazine half life in soil > soil hydraulic conductivity. Simulations from 1990 to 1995 with four different atrazine application rates applied at a constant rate throughout the simulation period showed concentrations in drain flow for the no-till plot to be twice those of the tilled plot. The differences were more pronounced in the early simulation period (1990–1992), partly because of the characteristics of macropore flow during large storms. The results suggest that RZWQM is a promising tool to study pesticide transport to subsurface drain flow under different tillage systems and application rates over several years, the concentrations of atrazine in drain flow can be higher with no-till than tilled soil over a range of atrazine application rates, and atrazine concentrations in drain flow are sensitive to the macropore flow characteristics under different tillage systems and rainfall timing and intensity.

Agro-waste biosorbents: Effect of physico-chemical properties on atrazine and imidacloprid sorption.

PubMed

Mandal, Abhishek; Singh, Neera; Nain, Lata

2017-09-02

Low cost agro-waste biosorbents namely eucalyptus bark (EB), corn cob (CC), bamboo chips (BC), rice straw (RS) and rice husk (RH) were characterized and used to study atrazine and imidacloprid sorption. Adsorption studies suggested that biosorbents greatly varied in their pesticide sorption behaviour. The EB was the best biosorbent to sorb both atrazine and imidacloprid with K F values of 169.9 and 85.71, respectively. The adsorption isotherm were nonlinear in nature with slope (1/n) values <1. The Freundlich constant Correlating atrazine/imidacloprid sorption parameter [K F .(1/n)] with the physicochemical properties of the biosorbents suggested that atrazine adsorption correlated significantly to the aromaticity, polarity, surface area, fractal dimension, lacunarity and relative C-O band intensity parameters of biosorbents. Probably, both physisorption and electrostatic interactions were responsible for the pesticide sorption. The eucalyptus bark can be exploited as low cost adsorbent for the removal of these pesticides as well as a component of on-farm biopurification systems.

Herbicide and degradate flux in the Yazoo River Basin

USGS Publications Warehouse

Coupe, R.H.; Welch, H.L.; Pell, A.B.; Thurman, E.M.

2005-01-01

During 1996-1997, water samples were collected from five sites in the Yazoo River Basin and analysed for 14 herbicides and nine degradates. These included acetochlor, alachlor, atrazine, cyanazine, fluometuron, metolachlor, metribuzin, molinate, norflurazon, prometryn, propanil, propazine, simazine, trifluralin, three degradates of fluometuron, two degradates of atrazine, one degradate of cyanazine, norflurazon, prometryn, and propanil. Fluxes generally were higher in 1997 than in 1996 due to a greater rainfall in 1997 than 1996. Fluxes were much larger from streams in the alluvial plain (an area of very productive farmland) than from the Skuna River in the bluff hills (an area of small farms, pasture, and forest). Adding the flux of the atrazine degradates to the atrazine flux increased the total atrazine flux by an average of 14.5%. The fluometuron degradates added about 10% to the total fluometuron flux, and adding the norflurazon degradate flux to the norflurazon flux increased the flux by 82% in 1996 and by 171% in 1997. ?? 2005 Taylor & Francis.

Toxicity of three pesticides individually and in mixture to larval grass shrimp (Palaemonetes pugio).

PubMed

Key, Peter; Chung, Katy; Siewicki, Tom; Fulton, Mike

2007-10-01

This study examined the toxicity of three pesticides, singly and in mixture, to grass shrimp (Palaemonetes pugio) larvae. The pesticides included atrazine, an herbicide used on turf grass and field crops; fipronil, a persistent insecticide used against termites and fire ants; and imidacloprid, a systemic insecticide used in agricultural and home products. Fipronil was the most toxic to shrimp larvae with a 96-h LC50 of 0.68microg/L (95% CI 0.57-0.79microg/L). Shrimp larvae were less sensitive to imidacloprid with a 96-h LC50 of 308.8microg/L (95% CI 273.6-348.6microg/L). Atrazine was non-toxic to shrimp larvae at concentrations up to 10,000microg/L. In mixtures, fipronil plus atrazine and imidacloprid plus atrazine had no change in toxicity compared to fipronil and imidacloprid tested singly. Similarly, a fipronil/imidacloprid mixture did not show greater than additive toxicity. However, when atrazine was added to the fipronil/imidacloprid mix, greater than additive toxicity occurred.

Reduction of nonpoint source contamination of surface water and groundwater by starch encapsulation of herbicides

USGS Publications Warehouse

Mills, M.S.; Thurman, E.M.

1994-01-01

The loss of the preemergent herbicide atrazine in surface runoff from experimental field plots growing corn (Zea mays L.) was significantly reduced using a starchencapsulated formulation versus a conventional powdered formulation. Field edge losses of starch-encapsulated atrazine were described as following a Rayleigh distribution totaling 1.8% of applied herbicide compared to exponential powdered atrazine losses of 2.9% applied - a 40% decrease. This has important implications for the reduction of nonpoint source contamination of surface water by agricultural chemicals. Unsaturated zone release of starchencapsulated atrazine was gradual, but comparable weed control was maintained. Deethylatrazine was a major dealkylated metabolite from each formulation, and deisopropylatrazine was a minor metabolite. The determination of soil partition coefficients for deethylatrazine and deisopropylatrazine (0.4 and 0.3, respectively), aqueous solubilities (3200 and 670 mg/L, respectively), and melting points (133 and 177 ??C, respectively) confirmed that the dealkylated metabolites should move more rapidly through the soil profile to groundwater than atrazine.

Effects of endosulfan, thiamethoxam, and indoxacarb in combination with atrazine on multi-biomarkers in Gammarus kischineffensis.

PubMed

Demirci, Özlem; Güven, Kemal; Asma, Dilek; Öğüt, Serdal; Uğurlu, Pelin

2018-01-01

Studies addressing the toxicity of pesticides towards non-target organisms focus on the median lethal concentration and biochemical response of individual pesticides. However, when determining environmental risks, it is important to test the combined effects of pesticides, such as insecticides and herbicides, which are frequently used together in agricultural areas. Here we aimed to investigate the toxic effects of the combined use of the herbicide atrazine and the insecticides, endosulfan, indoxacarb, and thiamethoxam on Gammarus kischineffensis. To do this, we tested the activities of oxidative stress, detoxification, and neurotoxicity biomarkers. Compared to atrazine alone, we detected higher glutathione-S-transferase, catalase and superoxide dismutase activities (oxidative stress biomarkers) when atrazine was combined with either endosulfan or indoxacarb. However, higher IBR values were determined in organisms where pesticide mixtures were used according to individual use. Based on these results, mixtures of atrazine and other pesticides may cause synergistic effects and may be evidence of increased toxicity and oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Properties comparison of biochars from corn straw with different pretreatment and sorption behaviour of atrazine.

PubMed

Zhao, Xuchen; Ouyang, Wei; Hao, Fanghua; Lin, Chunye; Wang, Fangli; Han, Sheng; Geng, Xiaojun

2013-11-01

Biochar has been recognised as an efficient pollution control material. In this study, biochars (CS450 and ADPCS450) were produced using corn straw with different pretreatment techniques (without and with ammonium dihydrogen phosphate (ADP)). The character of the two biochars was compared using elemental analysis, specific surface area (SSA) and Fourier transform infrared spectra (FTIR). ADPCS450 had a higher residue yield and a much larger specific surface area than CS450. The Freundlich, Langmuir and Redlich-Peterson models were used to interpret the sorption behaviour of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), and the results fit the Redlich-Peterson equation best. The isothermal sorption parameters indicated that the sorption capacity of atrazine on ADPCS450 was much larger than the sorption capacity of atrazine on CS450. Atrazine sorption was also favoured in acidic solution and under higher temperature conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Low Herbicide Concentration Found in Streamflow After a Grass Cover is Killed

Treesearch

J.E. Douglass; D.R. Cochrane; G.W. Bailey; J.I. Teasley; D.W. Hill

1969-01-01

The grass cover on a steep Appalachian watershed was sprayed in 1966 with herbicides-first with atrazine and paraquat and later with atrazine and 2,4-D. Although grass growing in the stream channel was sprayed during the first treatment, atrazine and paraquat levels in water samples were low. For the second treatment, a 10-foot strip on either side of the channel was...

Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

PubMed Central

Chen, Jun; Bai, Lian-Yang; Liu, Kun-Feng; Liu, Run-Qiang; Zhang, Yu-Ping

2014-01-01

Atrazine molecular imprinted polymers (MIPs) were comparatively synthesized using identical polymer formulation by far-infrared (FIR) radiation and ultraviolet (UV)-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high-and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF) and different selectivity index (SI) for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM), Fourier transform infrared absorption (FT-IR), and mercury analyzer (MA). Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE) of atrazine from lake water, followed by high performance liquid chromatography (HPLC) analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%), higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively. PMID:24398982

Atrazine Adsorption Potential of Leonardite from Mae Moh Power Plant

NASA Astrophysics Data System (ADS)

Rittirat, A.; Chokejaroenrat, C.; Watcharenwong, A.

2018-01-01

Leonardite is an immature coal from the power plant, which we obtained from Lampang province, Thailand. It is known to contain relatively high humic substance making it suitable as the soil conditioner in agricultural aspect and as an adsorbent. Our objectives were: [1] to determine the leonardite physical and chemical properties (e.g., cation exchange capacity, organic matter content, and electron microscope imaging), and (2) to quantify the adsorption efficiency of atrazine from the soil. We used varied amount of leonardite ranging from 0.05 to 1.60 g to adsorb 8 mg L-1 of atrazine from aqueous solution in a batch experiment. This experiment was achieved within 48 hours so that the equilibrium time and isotherm parameters can be determined. The uncarbonized leonardite characteristic revealed that it could adsorb atrazine as its surface possesses mesopore type, relatively high cation exchange capacity (59.89 cmol Kg-1), and high organic matter of 21.62 %. The isotherm study showed the equilibrium time of 24 hours and adsorption isotherm was Langmuir with qmax of 3.9683 mg g-1. This study provides proof that leonardite used in the agricultural field can also be useful to adsorb atrazine and simultaneously slow the percolating process of atrazine before contaminating groundwater.

Dimethoate and atrazine retention from aqueous solution by nanofiltration membranes.

PubMed

Ahmad, A L; Tan, L S; Shukor, S R Abd

2008-02-28

In order to produce sufficient food supply for the ever-increasing human population, pesticides usage is indispensable in the agriculture sector to control crop losses. However, the effect of pesticides on the environment is very complex as undesirable transfers occur continually among different environmental sections. This eventually leads to contamination of drinking water source especially for rivers located near active agriculture practices. This paper studied the application of nanofiltration membrane in the removal of dimethoate and atrazine in aqueous solution. Dimethoate was selected as the subject of study since it is being listed as one of the pesticides in guidelines for drinking water by World Health Organization. Nevertheless, data on effectiveness of dimethoate rejection using membranes has not been found so far. Meanwhile, atrazine is classified as one of the most commonly used pesticides in Malaysia. Separation was done using a small batch-type membrane separation cell with integrated magnetic stirrer while concentration of dimethoate and atrazine in aqueous solution was analyzed using high performance liquid chromatography (HPLC). Four nanofiltration membranes NF90, NF200, NF270 and DK were tested for their respective performance to separate dimethoate and atrazine. Of all four membranes, NF90 showed the best performance in retention of dimethoate and atrazine in water.

Impact of an atrazine-based herbicide on an agrobiont wolf spider.

PubMed

Godfrey, Jake A; Rypstra, Ann L

2018-06-01

For animals that live in association with humans, a key ecological question is how anthropogenic factors influence their life history. While major negative effects are obvious, subtle non-lethal responses to anthropogenic stimuli may provide insight into the features that lead to the success of species that thrive in habitats heavily impacted by humans. Here we explored the influence of the herbicide atrazine on various life history traits of a wolf spider that thrives in agroecosystems where it is commonly applied. We found that exposure delayed maturation and increased the probability of having molting errors. Atrazine also decreased the probability of producing an egg sac after mating, but increased the average mass of the initial egg sacs that were produced while not impacting the average number of eggs inside. The total number of eggs produced from a single mating on the other hand, was increased in the presence of atrazine through the production of multiple egg sacs. Finally, adult lifespan was shortened with exposure to atrazine. These results suggest that the atrazine based herbicides that are routinely applied to agricultural fields result in altered life history traits, potentially through endocrine disruption, that may counteract one another to allow persistence. Copyright © 2018 Elsevier Ltd. All rights reserved.

Herbicides in the Pecatonica, Trempealeau, and Yahara Rivers in Wisconsin, May 1997-July 1998

USGS Publications Warehouse

Graczyk, David J.; Vanden Brook, James P.; Rheineck, Bruce D.

1999-01-01

In 1997, Wisconsin farmers applied 8.7 million pounds of herbicides on corn. The five most commonly applied herbicides (in lb (pounds) of active ingredient per acre) on corn in 1997 were atrazine, metolachlor, acetochlor, alachlor and cyanazine. A 1996 study by the U.S. Geological Survey (USGS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) found that the most heavily applied agricultural herbicides were detected more frequently and at higher concentrations in the Pecatonica and Yahara Rivers in southern Wisconsin than the less heavily applied herbicides (Graczyk and Vanden Brook, 1997). The calculated herbicide loads a from May 15 to July 15, 1996 at the Pecatonica River ranged from 47.2 lb of alachlor to 484 lb of atrazine. For the Yahara River, loads ranged from 36.1 lb of alachlor to 289 lb of atrazine. The yields b (load per square mile) for atrazine were similar in the two water- sheds. This result was unexpected because the use of atrazine is prohibited on 94 percent of the Yahara River Watershed, but on only 4 percent of the Pecatonica River watershed. The unexpected atrazine result led to a continuation of the study in 1997 and 1998, when samples were collected again at the two sites sampled in 1996, and at a site in the upper third of the Yahara River Watershed that is entirely under atrazine use prohibition. For comparison purposes, a site in west-central Wisconsin also was sampled to determine herbicide loads and yields in another geographic area in the state

Determination of atrazine and simazine in water samples by high-performance liquid chromatography after preconcentration with heat-treated diatomaceous earth.

PubMed

Katsumata, Hideyuki; Kaneco, Satoshi; Suzuki, Tohru; Ohta, Kiyohisa

2006-09-08

A sensitive and selective column adsorption method is proposed for the preconcentration and determination of atrazine and simazine. Atrazine and simazine were preconcentrated on heat-treated diatomaceous earth as an adsorbent and then determined by high-performance liquid chromatography (HPLC). Several parameters on the recoveries of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 2 using 100 mL of validation solution containing 1.5 microg of triazines and 5 mL of ethanol as an eluent. Recoveries of atrazine and simazine were 95.7+/-4.2% and 75.0+/-1.9% with a relative standard deviation for seven determinations of 4.7% and 2.7% under optimum conditions. The maximum preconcentration factor was 100 for triazines when 500 mL of sample solution volume was used. The linear ranges of calibration curves for atrazine and simazine were 1-150 ng mL(-1) and 1-300 ng mL(-1), respectively, with correlation coefficients of 0.999 and the detection limits (3Signal-to-Noise) were 0.24 ng mL(-1) and 0.21 ng mL(-1) for atrazine and simazine. The capacity of the adsorbent was also examined and found to be 0.8 mg g(-1) and 1.3 mg g(-1) for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of triazines in river water and tap water samples with high precision and accuracy.

Test of direct and indirect effects of agrochemicals on the survival of fecal indicator bacteria.

PubMed

Staley, Zachery R; Rohr, Jason R; Harwood, Valerie J

2011-12-01

Water bodies often receive agrochemicals and animal waste carrying fecal indicator bacteria (FIB) and zoonotic pathogens, but we know little about the effects of agrochemicals on these microbes. We assessed the direct effects of the pesticides atrazine, malathion, and chlorothalonil and inorganic fertilizer on Escherichia coli and enterococcal survival in simplified microcosms held in the dark. E. coli strain composition in sediments and water column were positively correlated, but none of the agrochemicals had significant direct effects on E. coli strain composition or on densities of culturable FIBs. In a companion study, microcosms with nondisinfected pond water and sediments were exposed to or shielded from sunlight to examine the potential indirect effects of atrazine and inorganic fertilizer on E. coli. The herbicide atrazine had no effect on E. coli in dark-exposed microcosms containing natural microbial and algal communities. However, in light-exposed microcosms, atrazine significantly lowered E. coli densities in the water column and significantly increased densities in the sediment compared to controls. This effect appears to be mediated by the effects of atrazine on algae, given that atrazine significantly reduced phytoplankton, which was a positive and negative predictor of E. coli densities in the water column and sediment, respectively. These data suggest that atrazine does not directly affect the survival of FIB, rather that it indirectly alters the distribution and abundance of E. coli by altering phytoplankton and periphyton communities. These results improve our understanding of the influence of agricultural practices on FIB densities in water bodies impacted by agricultural runoff.

Test of Direct and Indirect Effects of Agrochemicals on the Survival of Fecal Indicator Bacteria▿

PubMed Central

Staley, Zachery R.; Rohr, Jason R.; Harwood, Valerie J.

2011-01-01

Water bodies often receive agrochemicals and animal waste carrying fecal indicator bacteria (FIB) and zoonotic pathogens, but we know little about the effects of agrochemicals on these microbes. We assessed the direct effects of the pesticides atrazine, malathion, and chlorothalonil and inorganic fertilizer on Escherichia coli and enterococcal survival in simplified microcosms held in the dark. E. coli strain composition in sediments and water column were positively correlated, but none of the agrochemicals had significant direct effects on E. coli strain composition or on densities of culturable FIBs. In a companion study, microcosms with nondisinfected pond water and sediments were exposed to or shielded from sunlight to examine the potential indirect effects of atrazine and inorganic fertilizer on E. coli. The herbicide atrazine had no effect on E. coli in dark-exposed microcosms containing natural microbial and algal communities. However, in light-exposed microcosms, atrazine significantly lowered E. coli densities in the water column and significantly increased densities in the sediment compared to controls. This effect appears to be mediated by the effects of atrazine on algae, given that atrazine significantly reduced phytoplankton, which was a positive and negative predictor of E. coli densities in the water column and sediment, respectively. These data suggest that atrazine does not directly affect the survival of FIB, rather that it indirectly alters the distribution and abundance of E. coli by altering phytoplankton and periphyton communities. These results improve our understanding of the influence of agricultural practices on FIB densities in water bodies impacted by agricultural runoff. PMID:22003017

Comparing atrazine and cyanuric acid electro-oxidation on mixed oxide and boron-doped diamond electrodes.

PubMed

Malpass, Geoffroy R P; Salazar-Banda, Giancarlo R; Miwa, Douglas W; Machado, Sérgio A S; Motheo, Artur J

2013-01-01

The breakdown of pesticides has been promoted by many methods for clean up of contaminated soil and wastewaters. The main goal is to decrease the toxicity of the parent compound to achieve non-toxic compounds or even, when complete mineralization occurs, carbon dioxide and water. Therefore, electrochemical degradation (potentiostatic and galvanostatic) of both the pesticide atrazine and cyanuric acid (CA) at boron-doped diamond (BDD) and Ti/Ru0.3Ti0.7O2 dimensionally stable anode (DSA) electrodes, in different supporting electrolytes (NaCl and Na2SO4), is presented with the aim of establishing the influence of the operational parameters on the process efficiency. The results demonstrate that both the electrode material and the supporting electrolyte have a strong influence on the rate of atrazine removal. In the chloride medium, the rate of atrazine removal is always greater than in sulfate under all conditions employed. Furthermore, in the sulfate medium, atrazine degradation was significant only at the BDD electrode. The total organic carbon (TOC) load decreased by 79% and 56% at the BDD and DSA electrodes, respectively, in the chloride medium. This trend was maintained in the sulfate medium but the TOC removal was lower (i.e. 33% and 13% at BDD and DSA electrodes, respectively). CA, a stable atrazine degradation intermediate, was also studied and it is efficiently removed using the BDD electrode in both media, mainly when high current densities are employed. The use of the BDD electrode in the chloride medium not only degrades atrazine but also mineralized cyanuric acid leading to the higher TOC removal.

The challenge of mapping between two medical coding systems.

PubMed

Wojcik, Barbara E; Stein, Catherine R; Devore, Raymond B; Hassell, L Harrison

2006-11-01

Deployable medical systems patient conditions (PCs) designate groups of patients with similar medical conditions and, therefore, similar treatment requirements. PCs are used by the U.S. military to estimate field medical resources needed in combat operations. Information associated with each of the 389 PCs is based on subject matter expert opinion, instead of direct derivation from standard medical codes. Currently, no mechanisms exist to tie current or historical medical data to PCs. Our study objective was to determine whether reliable conversion between PC codes and International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes is possible. Data were analyzed for three professional coders assigning all applicable ICD-9-CM diagnosis codes to each PC code. Inter-rater reliability was measured by using Cohen's K statistic and percent agreement. Methods were developed to calculate kappa statistics when multiple responses could be selected from many possible categories. Overall, we found moderate support for the possibility of reliable conversion between PCs and ICD-9-CM diagnoses (mean kappa = 0.61). Current PCs should be modified into a system that is verifiable with real data.

Hypospadias and maternal exposure to atrazine via drinking water in the National Birth Defects Prevention study.

PubMed

Winston, Jennifer J; Emch, Michael; Meyer, Robert E; Langlois, Peter; Weyer, Peter; Mosley, Bridget; Olshan, Andrew F; Band, Lawrence E; Luben, Thomas J

2016-07-15

Hypospadias is a relatively common birth defect affecting the male urinary tract. It has been suggested that exposure to endocrine disrupting chemicals might increase the risk of hypospadias by interrupting normal urethral development. Using data from the National Birth Defects Prevention Study, a population-based case-control study, we considered the role of maternal exposure to atrazine, a widely used herbicide and potential endocrine disruptor, via drinking water in the etiology of 2nd and 3rd degree hypospadias. We used data on 343 hypospadias cases and 1,422 male controls in North Carolina, Arkansas, Iowa, and Texas from 1998-2005. Using catchment level stream and groundwater contaminant models from the US Geological Survey, we estimated atrazine concentrations in public water supplies and in private wells. We assigned case and control mothers to public water supplies based on geocoded maternal address during the critical window of exposure for hypospadias (i.e., gestational weeks 6-16). Using maternal questionnaire data about water consumption and drinking water, we estimated a surrogate for total maternal consumption of atrazine via drinking water. We then included additional maternal covariates, including age, race/ethnicity, parity, and plurality, in logistic regression analyses to consider an association between atrazine and hypospadias. When controlling for maternal characteristics, any association between hypospadias and daily maternal atrazine exposure during the critical window of genitourinary development was found to be weak or null (odds ratio for atrazine in drinking water = 1. 00, 95 % CI = 0.97 to 1.03 per 0.04 μg/day increase; odds ratio for maternal consumption = 1.02, 95 % CI = 0.99 to 1.05; per 0.05 μg/day increase). While the association that we observed was weak, our results suggest that additional research into a possible association between atrazine and hypospadias occurrence, using a more sensitive exposure metric, would be useful.

Drinking-water exposure to a mixture of nitrate and low-dose atrazine metabolites and small-for-gestational age (SGA) babies: a historic cohort study.

PubMed

Migeot, V; Albouy-Llaty, M; Carles, C; Limousi, F; Strezlec, S; Dupuis, A; Rabouan, S

2013-04-01

Groundwater, surface water and drinking water are contaminated by nitrates and atrazine, an herbicide. They are present as a mixture in drinking water and with their endocrine-disrupting activity, they may alter fetal growth. To study an association between drinking-water atrazine metabolites/nitrate mixture exposure and small-for-gestational-age(SGA). A historic cohort study based on birth records and drinking-water nitrate and pesticide measurements in Deux-Sèvres (France) between 2005 and 2009 was carried out. Exposure to drinking-water atrazine metabolites/nitrate mixture was divided into 6 classes according to the presence or absence of atrazine metabolites and to terciles of nitrate concentrations in each trimester of pregnancy. Regression analysis of SGA by mixture exposure at second trimester was subsequently conducted. We included 11,446 woman-neonate couples of whom 37.0% were exposed to pesticides, while 99.9% of the women were exposed to nitrates. Average nitrate concentration was from 0 to 63.30 mg/L. In the second trimester of pregnancy, the risk of SGA was different with mixture exposure when drinking-water atrazine metabolites, mainly 2 hydroxyatrazine and desethylatrazine, were present and nitrate dose exposure increased: compared to single first tercile of nitrate concentration exposure, single second tercile exposure OR was 1.74 CI 95% [1.10; 2.75] and atrazine metabolites presence in the third tercile of nitrate concentration exposure OR was 0.87 CI 95% [0.45;1.67]. It is possible that the association found at the second trimester of exposure with regard to birth weight may likewise be observed before birth, with regard to the estimated fetal weight, and that it might change in the event that the atrazine metabolites dose were higher or the nitrate dose lower. It would appear necessary to further explore the variability of effects. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Watershed Regressions for Pesticides (WARP) for Predicting Annual Maximum and Annual Maximum Moving-Average Concentrations of Atrazine in Streams

USGS Publications Warehouse

Stone, Wesley W.; Gilliom, Robert J.; Crawford, Charles G.

2008-01-01

Regression models were developed for predicting annual maximum and selected annual maximum moving-average concentrations of atrazine in streams using the Watershed Regressions for Pesticides (WARP) methodology developed by the National Water-Quality Assessment Program (NAWQA) of the U.S. Geological Survey (USGS). The current effort builds on the original WARP models, which were based on the annual mean and selected percentiles of the annual frequency distribution of atrazine concentrations. Estimates of annual maximum and annual maximum moving-average concentrations for selected durations are needed to characterize the levels of atrazine and other pesticides for comparison to specific water-quality benchmarks for evaluation of potential concerns regarding human health or aquatic life. Separate regression models were derived for the annual maximum and annual maximum 21-day, 60-day, and 90-day moving-average concentrations. Development of the regression models used the same explanatory variables, transformations, model development data, model validation data, and regression methods as those used in the original development of WARP. The models accounted for 72 to 75 percent of the variability in the concentration statistics among the 112 sampling sites used for model development. Predicted concentration statistics from the four models were within a factor of 10 of the observed concentration statistics for most of the model development and validation sites. Overall, performance of the models for the development and validation sites supports the application of the WARP models for predicting annual maximum and selected annual maximum moving-average atrazine concentration in streams and provides a framework to interpret the predictions in terms of uncertainty. For streams with inadequate direct measurements of atrazine concentrations, the WARP model predictions for the annual maximum and the annual maximum moving-average atrazine concentrations can be used to characterize the probable levels of atrazine for comparison to specific water-quality benchmarks. Sites with a high probability of exceeding a benchmark for human health or aquatic life can be prioritized for monitoring.

Atrazine and metolachlor occurrence in shallow ground water of the United States, 1993 to 1995: Relations to explanatory factors

USGS Publications Warehouse

Kolpin, D.W.; Barbash, J.E.; Gilliom, R.J.

2002-01-01

Since 1991, the U.S. Geological Survey has been conducting the National Water Quality Assessment (NAWQA) Program to determine the quality of the Nation's water resources. In an effort to obtain a better understanding of why pesticides are found in shallow ground water on a national scale, a set of factors likely to affect the fate and transport of two herbicides in the subsurface were examined. Atrazine and metolachlor were selected for this discussion because they were among the most frequently detected pesticides in ground water during the first phase of the NAWQA Program (1993 to 1995), and each was the most frequently detected compound in its chemical class (triazines and acetanilides, respectively). The factors that most strongly correlated with the frequencies of atrazine detection in shallow ground-water networks were those that provided either: (1) an indication of the potential susceptibility of ground water to atrazine contamination, or (2) an indication of relative ground-water age. The factors most closely related to the frequencies of metolachlor detection in ground water, however, were those that estimated or indicated the intensity of the agricultural use of metolachlor. This difference is probably the result of detailed use estimates for these compounds being available only for agricultural settings. While atrazine use is relatively extensive in nonagricultural settings, in addition to its widespread agricultural use, metolachlor is used almost exclusively for agricultural purposes. As a result, estimates of agricultural applications provide a less reliable indication of total chemical use for atrazine than for metolachlor. A multivariate analysis demonstrated that the factors of interest explained about 50 percent of the variance in atrazine and metolachlor detection frequencies among the NAWQA land-use studies examined. The inclusion of other factors related to pesticide fate and transport in ground water, or improvements in the quality and accuracy of the data employed for the factors examined, may help explain more of the remaining variance in the frequencies of atrazine and metolachlor detection.

Reduced salinity increases susceptibility of zooxanthellate jellyfish to herbicide toxicity during a simulated rainfall event.

PubMed

Klein, Shannon G; Pitt, Kylie A; Carroll, Anthony R

2016-02-01

Accurately predicting how marine biota are likely to respond to changing ocean conditions requires accurate simulation of interacting stressors, exposure regimes and recovery periods. Jellyfish populations have increased in some parts of the world and, despite few direct empirical tests, are hypothesised to be increasing because they are robust to a range of environmental stressors. Here, we investigated the effects of contaminated runoff on a zooxanthellate jellyfish by exposing juvenile Cassiopea sp. medusae to a photosystem II (PSII) herbicide, atrazine and reduced salinity conditions that occur following rainfall. Four levels of atrazine (0ngL(-1), 10ngL(-1), 2μgL(-1), 20μgL(-1)) and three levels of salinity (35 ppt, 25 ppt, 17 ppt) were varied, mimicking the timeline of light, moderate and heavy rainfall events. Normal conditions were then slowly re-established over four days to mimic the recovery of the ecosystem post-rain and the experiment continued for a further 7 days to observe potential recovery of the medusae. Pulse-amplitude modulated (PAM) chlorophyll fluorescence, growth and bell contraction rates of medusae were measured. Medusae exposed to the combination of high atrazine and lowest salinity died. After 3 days of exposure, bell contraction rates were reduced by 88% and medusae were 16% smaller in the lowest salinity treatments. By Day 5 of the experiment, all medusae that survived the initial pulse event began to recover quickly. Although atrazine decreased YII under normal salinity conditions, YII was further reduced when medusae were exposed to both low salinity and atrazine simultaneously. Atrazine breakdown products were more concentrated in jellyfish tissues than atrazine at the end of the experiment, suggesting that although bioaccumulation occurred, atrazine was metabolised. Our results suggest that reduced salinity may increase the susceptibility of medusae to herbicide exposure during heavy rainfall events. Copyright © 2015 Elsevier Ltd. All rights reserved.

SRGULL - AN ADVANCED ENGINEERING MODEL FOR THE PREDICTION OF AIRFRAME INTEGRATED SCRAMJET CYCLE PERFORMANCE

NASA Technical Reports Server (NTRS)

Walton, J. T.

1994-01-01

The development of a single-stage-to-orbit aerospace vehicle intended to be launched horizontally into low Earth orbit, such as the National Aero-Space Plane (NASP), has concentrated on the use of the supersonic combustion ramjet (scramjet) propulsion cycle. SRGULL, a scramjet cycle analysis code, is an engineer's tool capable of nose-to-tail, hydrogen-fueled, airframe-integrated scramjet simulation in a real gas flow with equilibrium thermodynamic properties. This program facilitates initial estimates of scramjet cycle performance by linking a two-dimensional forebody, inlet and nozzle code with a one-dimensional combustor code. Five computer codes (SCRAM, SEAGUL, INLET, Progam HUD, and GASH) originally developed at NASA Langley Research Center in support of hypersonic technology are integrated in this program to analyze changing flow conditions. The one-dimensional combustor code is based on the combustor subroutine from SCRAM and the two-dimensional coding is based on an inviscid Euler program (SEAGUL). Kinetic energy efficiency input for sidewall area variation modeling can be calculated by the INLET program code. At the completion of inviscid component analysis, Program HUD, an integral boundary layer code based on the Spaulding-Chi method, is applied to determine the friction coefficient which is then used in a modified Reynolds Analogy to calculate heat transfer. Real gas flow properties such as flow composition, enthalpy, entropy, and density are calculated by the subroutine GASH. Combustor input conditions are taken from one-dimensionalizing the two-dimensional inlet exit flow. The SEAGUL portions of this program are limited to supersonic flows, but the combustor (SCRAM) section can handle supersonic and dual-mode operation. SRGULL has been compared to scramjet engine tests with excellent results. SRGULL was written in FORTRAN 77 on an IBM PC compatible using IBM's FORTRAN/2 or Microway's NDP386 F77 compiler. The program is fully user interactive, but can also run in batch mode. It operates under the UNIX, VMS, NOS, and DOS operating systems. The source code is not directly compatible with all PC compilers (e.g., Lahey or Microsoft FORTRAN) due to block and segment size requirements. SRGULL executable code requires about 490K RAM and a math coprocessor on PC's. The SRGULL program was developed in 1989, although the component programs originated in the 1960's and 1970's. IBM, IBM PC, and DOS are registered trademarks of International Business Machines. VMS is a registered trademark of Digital Equipment Corporation. UNIX is a registered trademark of Bell Laboratories. NOS is a registered trademark of Control Data Corporation.

AN ENVIRONMENTAL TECHNOLOGY VERIFICATION (ETV) OF FOUR TEST KITS FOR THE ANALYSIS OF ATRAZINE IN WATER: ABRAXIS LLC ATRAZINE ELISA KIT, BEACON ANALYTICAL SYSTEMS, INC. ATRAZINE TUBE KIT, SILVER LAKE RESEARCH CORP. WATERSAFE PESTICIDE TEST AND STRATEGIC DIAGNOSTICS, INC. RAPID ASSAY KIT

EPA Science Inventory

The Environmental Technology Verification (ETV) Program, beginning as an initiative of the U.S. Environmental Protection Agency (EPA) in 1995, verifies the performance of commercially available, innovative technologies that can be used to measure environmental quality. The ETV ...

Performance characteristics of the Cooper PC-9 centrifugal compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, R.E.; Neely, R.F.

1988-06-30

Mathematical performance modeling of the PC-9 centrifugal compressor has been completed. Performance characteristics curves have never been obtained for them in test loops with the same degree of accuracy as for the uprated axial compressors and, consequently, computer modeling of the top cascade and purge cascades has been very difficult and of limited value. This compressor modeling work has been carried out in an attempt to generate data which would more accurately define the compressor's performance and would permit more accurate cascade modeling. A computer code, COMPAL, was used to mathematically model the PC-9 performance with variations in gas composition,more » flow ratios, pressure ratios, speed and temperature. The results of this effort, in the form of graphs, with information about the compressor and the code, are the subject of this report. Compressor characteristic curves are featured. 13 figs.« less

[Quality of registration of dementia diagnosis in primary care: The situation in Spain in 2002-2011].

PubMed

de Hoyos-Alonso, María del Canto; Bonis, Julio; Bryant, Verónica; Castell Alcalá, María Victoria; Otero Puime, Ángel

2016-01-01

To ascertain the diagnosis associated with specific treatment for dementia in the Primary Care Electronic Clinical Record (PC-ECR) and to analyse the factors associated with the quality of registration. Descriptive study of patients taking cholinesterase inhibitors or memantine registered in Database for pharmacoepidemiological research in PC (BIFAP) 2011: 24,575 patients between 2002 and 2011. Diagnoses associated with first prescription of these drugs were grouped into 5 categories: "dementia", "memory impairment", "dementia-related diseases", "intercurrent processes" and "convenience codes". We calculated the prevalence of each category by age and sex for each study year (95%CI) and analysed the associations and trend for 2002-2011 using difference in proportions in independent samples and binary logistic regression. A code of "dementia" was associated with first prescription in 56.5% (95%CI: 55.8-57.1) of patients. It was higher in women [OR1.09 (95%CI: 1.03-1.15)] and with increasing follow-up time [OR1.07 (95%CI: 1.06-1.08) for each year of follow-up]. "Convenience codes" [16.3% (95%CI: 15.8-16.7)] were coded more frequently in women and in those ≥80 years; "Memory impairment" [12.4% (95%CI: 12.0-12.8)], "related diseases" [4.6% (95%CI: 4.4-4.8)] and "intercurrent processes" [10.3% (95%CI: 9.9-10.6)] were used more in men and in persons <80 years. Between 2002 and 2011 improved the use of "convenience codes". Almost half of the patients taking cholinesterase inhibitors or memantine do not have a diagnosis of dementia registered in their PC-ECR. Registration improves with increasing time of follow-up. Improvements are needed in the PC-ECR, adequate care coordination, and proactive approach to increase the quality of dementia registration. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Atrazine induced epigenetic transgenerational inheritance of disease, lean phenotype and sperm epimutation pathology biomarkers

PubMed Central

McBirney, Margaux; King, Stephanie E.; Pappalardo, Michelle; Houser, Elizabeth; Unkefer, Margaret; Nilsson, Eric; Sadler-Riggleman, Ingrid; Beck, Daniel; Winchester, Paul

2017-01-01

Ancestral environmental exposures to a variety of environmental toxicants and other factors have been shown to promote the epigenetic transgenerational inheritance of adult onset disease. The current study examined the potential transgenerational actions of the herbicide atrazine. Atrazine is one of the most commonly used herbicides in the agricultural industry, in particular with corn and soy crops. Outbred gestating female rats were transiently exposed to a vehicle control or atrazine. The F1 generation offspring were bred to generate the F2 generation and then the F2 generation bred to generate the F3 generation. The F1, F2 and F3 generation control and atrazine lineage rats were aged and various pathologies investigated. The male sperm were collected to investigate DNA methylation differences between the control and atrazine lineage sperm. The F1 generation offspring (directly exposed as a fetus) did not develop disease, but weighed less compared to controls. The F2 generation (grand-offspring) was found to have increased frequency of testis disease and mammary tumors in males and females, early onset puberty in males, and decreased body weight in females compared to controls. The transgenerational F3 generation rats were found to have increased frequency of testis disease, early onset puberty in females, behavioral alterations (motor hyperactivity) and a lean phenotype in males and females. The frequency of multiple diseases was significantly higher in the transgenerational F3 generation atrazine lineage males and females. The transgenerational transmission of disease requires germline (egg or sperm) epigenetic alterations. The sperm differential DNA methylation regions (DMRs), termed epimutations, induced by atrazine were identified in the F1, F2 and F3 generations. Gene associations with the DMRs were identified. For the transgenerational F3 generation sperm, unique sets of DMRs (epimutations) were found to be associated with the lean phenotype or testis disease. These DMRs provide potential biomarkers for transgenerational disease. The etiology of disease appears to be in part due to environmentally induced epigenetic transgenerational inheritance, and epigenetic biomarkers may facilitate the diagnosis of the ancestral exposure and disease susceptibility. Observations indicate that although atrazine does not promote disease in the directly exposed F1 generation, it does have the capacity to promote the epigenetic transgenerational inheritance of disease. PMID:28931070

Herbicide concentrations in and loads transported by the Conestoga River and Pequea Creek, Lancaster County, Pennsylvania, 1992-95

USGS Publications Warehouse

Reed, Lloyd A.; Koerkle, Edward H.; Takita, Charles S.

1997-01-01

Water samples were collected from four streams in Lancaster County from 1992 through 1995 and analyzed for selected herbicides. Samples were collected from the Little Conestoga Creek near Churchtown, Mill Creek (a tributary to the Conestoga River) at Elshelman Mill Road near Lyndon, the Conestoga River at Conestoga, and Pequea Creek at Martic Forge. Most samples were collected from stormflow that occurred during the growing season. Samples were analyzed for alachlor, aldrin, atrazine, chlordane, cyanazine, dieldrin, malathion, metolachlor, propazine, simazine, and toxaphene. Most samples had detectable concentrations of alachlor, atrazine, metolachlor, and simazine, and the loads of these constituents that were transported during each of the 4 years were computed.Of the samples collected from each of the streams—Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek—10, 12, 15, and 18 percent, respectively, had atrazine concentrations greater than 3.0 micrograms per liter, the U.S. Environmental Protection Agency maximum contaminant level. Loads of atrazine, metolochlor, and simazine were greater than loads of any other herbicides. The largest loads were transported during 1994. Loads of atrazine transported by the four streams during periods of storm- flow from May to September 1994 totaled 3.46, 28.3, 263, and 46.8 pounds, respectively. The total loads of atrazine transported by the four streams?Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek—during calendar year 1994 were 6.48, 54.1, 498, and 102 pounds, respectively. A little less than half the atrazine load transported by each stream—45, 39, 42, and 42 percent, respectively—was transported during storms that occurred from May through September.Average annual yields of atrazine for the period 1992-95 were 0.59, 0.64, 0.68, and 0.51 pounds per square mile from the Little Conestoga Creek, Mill Creek, Conestoga River, and Pequea Creek, respectively. Average annual yields of simazine were 0.36, 1.2, 0.54, and 0.48 pounds per square mile, respectively, and average annual yields of metolachlor were 0.46, 0.49, 0.54, and 0.31 pounds per square mile, respectively. Less than 1 percent of both the atrazine and metolachlor that was applied to all basins was transported by streamflow.

Occurrence and load of selected herbicides and metabolites in the lower Mississippi River

USGS Publications Warehouse

Clark, G.M.; Goolsby, D.A.

2000-01-01

Analyses of water samples collected from the Mississippi River at Baton Rouge, Louisiana, during 1991-1997 indicate that hundreds of metric tons of herbicides and herbicide metabolites are being discharged annually to the Gulf of Mexico. Atrazine, metolachlor, and the ethane-sulfonic acid metabolite of alachlor (alachlor ESA) were the most frequently detected herbicides and, in general, were present in the largest concentrations. Almost 80% of the annual herbicide load to the Gulf of Mexico occurred during the growing season from May to August. The concentrations and loads of alachlor in the Mississippi River decreased dramatically after 1993 in response to decreased use in the basin. In contrast, the concentrations and loads of acetochlor increased after 1994, reflecting its role as a replacement for alachlor. The peak annual herbicide load occurred in 1993, when approximately 640 metric tons (t) of atrazine, 320 t of cyanazine, 215 t of metolachlor, 53 t of simazine, and 50 t of alachlor were discharged to the Gulf of Mexico. The annual loads of atrazine and cyanazine were generally 1-2% of the amount annually applied in the Mississippi River drainage basin; the annual loads of acetochlor, alachlor, and metolachlor were generally less than 1%. Despite a reduction in atrazine use, historical data do not indicate a long-term downward trend in the atrazine load to the Gulf of Mexico. Although a relation (r2=0.62) exists between the atrazine load and stream discharge during May to August, variations in herbicide use and rainfall patterns within subbasins can have a large effect on herbicide loads in the Mississippi River Basin and probably explain a large part of the annual variation in atrazine load to the Gulf of Mexico. Copyright (C) 2000 Elsevier Science B.V.

Occurrence and load of selected herbicides and metabolites in the lower Mississippi River

USGS Publications Warehouse

Clark, Gregory M.; Goolsby, Donald A.

2000-01-01

Analyses of water samples collected from the Mississippi River at Baton Rouge, Louisiana, during 1991–1997 indicate that hundreds of metric tons of herbicides and herbicide metabolites are being discharged annually to the Gulf of Mexico. Atrazine, metolachlor, and the ethane-sulfonic acid metabolite of alachlor (alachlor ESA) were the most frequently detected herbicides and, in general, were present in the largest concentrations. Almost 80% of the annual herbicide load to the Gulf of Mexico occurred during the growing season from May to August. The concentrations and loads of alachlor in the Mississippi River decreased dramatically after 1993 in response to decreased use in the basin. In contrast, the concentrations and loads of acetochlor increased after 1994, reflecting its role as a replacement for alachlor. The peak annual herbicide load occurred in 1993, when approximately 640 metric tons (t) of atrazine, 320 t of cyanazine, 215 t of metolachlor, 53 t of simazine, and 50 t of alachlor were discharged to the Gulf of Mexico. The annual loads of atrazine and cyanazine were generally 1–2% of the amount annually applied in the Mississippi River drainage basin; the annual loads of acetochlor, alachlor, and metolachlor were generally less than 1%. Despite a reduction in atrazine use, historical data do not indicate a long-term downward trend in the atrazine load to the Gulf of Mexico. Although a relation (r2=0.62) exists between the atrazine load and stream discharge during May to August, variations in herbicide use and rainfall patterns within subbasins can have a large effect on herbicide loads in the Mississippi River Basin and probably explain a large part of the annual variation in atrazine load to the Gulf of Mexico.

Impact of long-term wastewater irrigation on sorption and transport of atrazine in Mexican agricultural soils.

PubMed

Müller, K; Duwig, C; Prado, B; Siebe, C; Hidalgo, C; Etchevers, J

2012-01-01

In the Mezquital Valley, Mexico, crops have been irrigated with untreated municipal wastewater for more than a century. Atrazine has been applied to maize and alfalfa grown in the area for weed control for 15 years. Our objectives were to analyse (i) how wastewater irrigation affects the filtering of atrazine, and (ii) if the length of irrigation has a significant impact. We compared atrazine sorption to Phaeozems that have been irrigated with raw wastewater for 35 (P35) and 85 (P85) years with sorption to a non-irrigated (P0) Phaeozem soil under rainfed agriculture. The use of bromide as an inert water tracer in column experiments and the subsequent analysis of the tracers' breakthrough curves allowed the calibration of the hydrodynamic parameters of a two-site non equilibrium convection-dispersion model. The quality of the irrigation water significantly altered the soils' hydrodynamic properties (hydraulic conductivity, dispersivity and the size of pores that are hydraulically active). The impacts on soil chemical properties (total organic carbon content and pH) were not significant, while the sodium adsorption ratio was significantly increased. Sorption and desorption isotherms, determined in batch and column experiments, showed enhanced atrazine sorption and reduced and slower desorption in wastewater-irrigated soils. These effects increased with the length of irrigation. The intensified sorption-desorption hysteresis in wastewater-irrigated soils indicated that the soil organic matter developed in these soils had fewer high-energy, easily accessible sorption sites available, leading to lower and slower atrazine desorption rates. This study leads to the conclusion that wastewater irrigation decreases atrazine mobility in the Mezquital valley Phaeozems by decreasing the hydraulic conductivity and increasing the soil's sorption capacity.

Controls on atrazine leaching through a soil-unsaturated fractured limestone sequence at Brévilles, France.

PubMed

Roulier, Stéphanie; Baran, Nicole; Mouvet, Christophe; Stenemo, Fredrik; Morvan, Xavier; Albrechtsen, Hans-Jørgen; Clausen, Liselotte; Jarvis, Nicholas

2006-03-01

The objective of this study was to identify the main controls on atrazine leaching through luvisols and calcisols overlying fissured limestone using the dual-permeability model MACRO. The model parameterisation was based on a combination of direct measurements (e.g. hydraulic properties, adsorption and degradation), literature data and calibration against bromide leaching experiments in field plots. A Monte Carlo sensitivity analysis was carried out for a typical application pattern, considering two different depths of unsaturated limestone (15 and 30 m). MACRO calibrations to the field experiments demonstrated the occurrence of strong macropore flow in the luvisol, while transport in the calcisol could be described by the advection-dispersion equation. MACRO simulations of tritium and atrazine leaching qualitatively matched tritium concentration profiles measured in the limestone and atrazine concentrations measured in piezometers and in aquifer discharge via a spring. The sensitivity analysis suggested that the thickness of the limestone, as well as the transport properties and processes occurring in the unsaturated rock (e.g. matrix vs. fissure flow) will have little significant long-term effect on atrazine leaching, mainly because degradation is very slow in the limestone. No mineralization of atrazine was detected in one-year incubations and a mean half-life of 10 years was assumed in the simulations. Instead, processes occurring in the soil exerted the main control on predicted atrazine leaching, especially variations in the degradation rate and the strength of sorption and macropore flow. However, fissure flow in unsaturated rock is expected to exert a much more significant control on groundwater contamination for compounds that degrade more readily in the deep vadose zone.

Effects of atrazine on cytochrome P450 enzymes of zebrafish (Danio rerio).

PubMed

Dong, Xiaoli; Zhu, Lusheng; Wang, Jinhua; Wang, Jun; Xie, Hui; Hou, Xinxin; Jia, Wentao

2009-10-01

In this study, the effects of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in males and females of adult zebrafish (Danio rerio) were studied. The liver microsomal cytochrome P450 content, NADPH-P450 reductase, aminopyrine N-demethylase (APND), and erythromycin N-demethylase (ERND) activity were measured. Zebrafish were exposed to control and 3 treatments (0.01, 0.1, and 1 mg L(-1)) of atrazine for 5, 10, 15, 20, and 25 days. The results indicated that, within the range of test atrazine concentrations, either P450 content or P450 isozyme activities could be induced by atrazine. Compared to controls, P450 content was significantly increased at all atrazine concentrations at days 10, 15, and 20; thereafter, at day 25, all concentrations decreased to approximately the control levels, both in males and females. In addition, the strongest induction of P450 content was observed on day 15 in males and day 10 in females at treatment concentrations of 1 mg L(-1). NADPH-P450 reductase activities showed mild increase in males; however, the females exhibited significant induction on days 15, 20, and 25; especially, at concentrations of 0.01 mg L(-1), the induction level was consistently increased during the experiment. The inducements of APND and ERND in males were mainly observed on the days 5, 10, and 15, which showed less distinct induction, while significant induction was observed in cases of treatments during all days in females. In conclusion, atrazine induces P450 enzymes in zebrafish, and the effects may function as significant toxicity mechanisms in zebrafish. Additionally, it also confirms the importance of using a combined multi-time and multi-index diagnostic method to enhance the sensitivity and effectiveness of the indices adopted.

Atrazine degradation by fungal co-culture enzyme extracts under different soil conditions.

PubMed

Chan-Cupul, Wilberth; Heredia-Abarca, Gabriela; Rodríguez-Vázquez, Refugio

2016-01-01

This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g(-1)) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 2(4) factorial experimental design. The Trametes maxima-Paecilomyces carneus co-culture extract contained more laccase activity and hydrogen peroxide (H2O2) content (laccase = 18956.0 U mg protein(-1), H2O2 = 6.2 mg L(-1)) than the T. maxima monoculture extract (laccase = 12866.7 U mg protein(-1), H2O2 = 4.0 mg L(-1)). Both extracts were able to degrade atrazine at 100%; however, the T. maxima monoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture with P. carneus (1.2 h). The FEE type (p = 0.03) and soil pH (p = 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by the T. maxima monoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strain T. maxima and its co-culture with P. carneus can efficiently and quickly degrade atrazine in clay-loam soils.

Cyanazine, Atrazine, and Their Metabolites as Geochemical Indicators of Contaminant Transport in the Mississippi River

USGS Publications Warehouse

Meyer, M.T.; Thurman, E.M.; Goolsby, D.A.

1996-01-01

The geochemical transport of cyanazine and its metabolite cyanazine amide (CAM) was compared to atrazine and its metabolite deethylatrazine (DEA) at three sites in the Mississippi River basin during 1992 and six sites during 1993. The floods of 1993 caused an uninterrupted exponential decline in herbicide concentrations; whereas, in 1992 herbicide concentrations varied mostly in response to two discrete discharge pulses in the spring and midsummer and were stable during an extended period of summer low-flow. Concentration half-lives calculated from the 1993 data for atrazine were approximately twice those of cyanazine at all sites. The half-life for atrazine and cyanazine was shortest, 22 and 14 days, respectively at the Mississippi River at Clinton, Ill. - the farthest upstream site - and longest, 42 and 22 days, respectively, at the Baton Rouge, La. site - the farthest downstream site. The concentration of CAM exceeded the concentration of DEA through September at all sites where the mean ratio of atrazine-to-cyanazine (ACR) was less than 4.0. The ratio of CAM-to-cyanazine (CAMCR) increased from 0.2 to more than 1.0 and the ratio of DEA-to-atrazine (DAR) increased from less than 0.1 to 0.3 from application in May through early to mid-July. Temporal changes in the CAMCR were used to identify pre- and post-application "slugs" of water transported along the reaches of the Mississippi River.

The enhancement of atrazine sorption and microbial transformation in biochars amended black soils.

PubMed

Yang, Fan; Zhang, Wei; Li, Jinmei; Wang, Shuyao; Tao, Yue; Wang, Yifan; Zhang, Ying

2017-12-01

Generally, biochar plays an important role in controlling migration and accumulation of pollutants in soil. In this dissertation, biochars derived from wheat straws at various pyrolysis temperatures are used to investigate how biochar amendment affects adsorption and microbial degradation of atrazine (typical diffuse herbicide) in soils. In order to explore the influence of soil components, soil samples with different organic matter content are collected from typical agricultural sites, which are characterized as black soils in the northeast region of China. The basic sorption characteristics of biochars from wheat straws prepared at diverse pyrolysis temperature are analyzed, along with the comparisons of the sorption difference in the raw soil and soil amended with biochars at four levels of ratio (0.1%, 0.5%, 1.0% and 2.0%). By incubation experiments, atrazine degradation in non-sterile and sterile soils and effects of atrazine degradation rate after biochar amendment are also studied. Atrazine degradation is significantly enhanced in biochar amended soils, which may be because that biochar supplement can promote the growth and metabolism of microorganisms in the soil. Our findings reveal that wheatstraw- derived biochars may be effective remediation reagents for activating degradation of the soil functional microorganism and enhancing sorption of organic matter content, which can be applied to environmental-friendly accelerate the remediation of atrazine contaminated black soils. Copyright © 2017. Published by Elsevier Ltd.

The effects of gestational and chronic atrazine exposure on motor behaviors and striatal dopamine in male Sprague-Dawley rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walters, Jennifer L., E-mail: Jennifer.l.walters@wmich.edu; Lansdell, Theresa A., E-mail: lansdel1@msu.edu; Lookingland, Keith J., E-mail: lookingl@msu.edu

This study sought to investigate the effects of environmentally relevant gestational followed by continued chronic exposure to the herbicide, atrazine, on motor function, cognition, and neurochemical indices of nigrostriatal dopamine (DA) activity in male rats. Dams were treated with 100 μg/kg atrazine, 10 mg/kg atrazine, or vehicle on gestational day 1 through postnatal day 21. Upon weaning, male offspring continued daily vehicle or atrazine gavage treatments for an additional six months. Subjects were tested in a series of behavioral assays, and 24 h after the last treatment, tissue samples from the striatum were analyzed for DA and 3,4-dihydroxyphenylacetic acid (DOPAC).more » At 10 mg/kg, this herbicide was found to produce modest disruptions in motor functioning, and at both dose levels it significantly lowered striatal DA and DOPAC concentrations. These results suggest that exposures to atrazine have the potential to disrupt nigrostriatal DA neurons and behaviors associated with motor functioning. - Highlights: • Male rats received gestational and chronic exposure to ATZ (10 mg/kg and 100 μg/kg). • ATZ altered locomotor activity and impaired motor coordination. • ATZ lowered striatal DA and DOPAC concentrations. • ATZ produced a potential anxiogenic effect. • ATZ did not impair performance in learning and memory assessments.« less

A collection of cytochrome P450 monooxygenase genes involved in modification and detoxification of herbicide atrazine in rice (Oryza sativa) plants.

PubMed

Rong Tan, Li; Chen Lu, Yi; Jing Zhang, Jing; Luo, Fang; Yang, Hong

2015-09-01

Plant cytochrome P450 monooxygenases constitute one of the largest families of protein genes involved in plant growth, development and acclimation to biotic and abiotic stresses. However, whether these genes respond to organic toxic compounds and their biological functions for detoxifying toxic compounds such as herbicides in rice are poorly understood. The present study identified 201 genes encoding cytochrome P450s from an atrazine-exposed rice transcriptome through high-throughput sequencing. Of these, 69 cytochrome P450 genes were validated by microarray and some of them were confirmed by real time PCR. Activities of NADPH-cytochrome P450 reductase (CPR) and p-nitroanisole O-demethylase (PNOD) related to toxicity were determined and significantly induced by atrazine exposure. To dissect the mechanism underlying atrazine modification and detoxification by P450, metabolites (or derivatives) of atrazine in plants were analyzed by ultra performance liquid chromatography mass spectrometry (UPLC/MS). Major metabolites comprised desmethylatrazine (DMA), desethylatrazine (DEA), desisopropylatrazine (DIA), hydroxyatrazine (HA), hydroxyethylatrazine (HEA) and hydroxyisopropylatrazine (HIA). All of them were chemically modified by P450s. Furthermore, two specific inhibitors of piperonyl butoxide (PBO) and malathion (MAL) were used to assess the correlation between the P450s activity and rice responses including accumulation of atrazine in tissues, shoot and root growth and detoxification. Copyright © 2015 Elsevier Inc. All rights reserved.

Atrazine in Surface Water and Relation to Hydrologic Conditions Within the Delaware River Basin Pesticide Management Area, Northeast Kansas, July 1992 Through December 1994

USGS Publications Warehouse

Pope, Larry M.

1995-01-01

Since about 1960, atrazine has been used as an effective pre- and postemergent herbicide in the production of corn and grain sorghum. Atrazine is a triazine-class herbicide and was the most frequently detected herbicide in surface water of the lower Kansas River Basin of southeast Nebraska and northeast Kansas (Stamer and Zelt, 1994). Approximately 95 percent of the atrazine applied in the United States is used in corn and grain-sorghum production, predominately in the Mississippi River Basin where about 82 percent of the Nation's corn acreage is planted (CIBA-GEIGY Corp., 1992). Until recent changes in product labeling, atrazine commonly was applied at relatively high rates to control weeds around commercial and industrial areas and along railroad right-of-ways. Crop yields have increased during the last 40 years due in part to the use of herbicides in reducing weed growth and competition for moisture and nutrients. However, concern on the part of water suppliers, health officials, and the public also has increased regarding the safe and responsible use of herbicides. One issue is whether the widespread use of atrazine may pose a potential threat to public-water supplies in areas where the herbicide is used because of its ability to easily dissolve in water and its possible effects on the health of humans and aquatic life.

Photoelectrocatalytic degradation of atrazine by boron-fluorine co-doped TiO2 nanotube arrays.

PubMed

Wang, He-Xuan; Zhu, Li-Nan; Guo, Fu-Qiao

2018-06-23

Atrazine, one of the most widespread herbicides in the world, is considered as an environmental estrogen and has potential carcinogenicity. In this study, atrazine was degraded on boron-fluorine co-doped TiO 2 nanotube arrays (B, F-TiO 2 NTAs), which had similar morphology with the pristine TiO 2 NTAs. The structure and morphology of TiO 2 nanotube samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible diffuse reflectance spectroscopy (DRS). It showed that the decoration of fluorine and boron made both the absorption in the visible region enhanced and the band edge absorption shifted. The efficiency of atrazine degradation by B, F-TiO 2 NTAs through photoelectrocatalysis was investigated by current, solution pH, and electrolyte concentration, respectively. The atrazine removal rate reached 76% through photoelectrocatalytic reaction by B, F-TiO 2 NTAs, which was 46% higher than that under the photocatalysis process. Moreover, the maximum degradation rate was achieved at pH of 6 in 0.01 M of Na 2 SO 4 electrolyte solution under a current of 0.02 A and visible light for 2 h in the presence of B, F-TiO 2 NTAs. These results showed that B, F-TiO 2 NTAs exhibit remarkable photoelectrocatalytic activity in degradation of atrazine.

Risk-cost-benefit analysis of atrazine in drinking water from agricultural activities and policy implications

NASA Astrophysics Data System (ADS)

Tesfamichael, Aklilu A.; Caplan, Arthur J.; Kaluarachchi, Jagath J.

2005-05-01

This study provides an improved methodology for investigating the trade-offs between the health risks and economic benefits of using atrazine in the agricultural sector by incorporating public attitude to pesticide management in the analysis. Regression models are developed to predict finished water atrazine concentration in high-risk community water supplies in the United States. The predicted finished water atrazine concentrations are then used in a health risk assessment. The computed health risks are compared with the total economic surplus in the U.S. corn market for different atrazine application rates using estimated demand and supply functions developed in this work. Analysis of different scenarios with consumer price premiums for chemical-free and reduced-chemical corn indicate that if the society is willing to pay a price premium, risks can be reduced without a large reduction in the total economic surplus and net benefits may be higher. The results also show that this methodology provides an improved scientific framework for future decision making and policy evaluation in pesticide management.

Determination of the atrazine migration parameters in Vertisol

NASA Astrophysics Data System (ADS)

Raymundo-Raymundo, E.; Hernandez-Vargas, J.; Nikol'Skii, Yu. N.; Guber, A. K.; Gavi-Reyes, F.; Prado-Pano, B. L.; Figueroa-Sandoval, B.; Mendosa-Hernandez, J. R.

2010-05-01

The parameters of the atrazine migration in columns with undisturbed Vertisol sampled from an irrigated plot in Guanajuato, Mexico were determined. A model of the convection-dispersion transport of the chemical compounds accounting for the decomposition and equilibrium adsorption, which is widely applied for assessing the risk of contamination of natural waters with pesticides, was used. The model parameters were obtained by solving the inverse problem of the transport equation on the basis of laboratory experiments on the transport of the 18O isotope and atrazine in soil columns with an undisturbed structure at three filtration velocities. The model adequately described the experimental data at the individual selection of the parameters for each output curve. Physically unsubstantiated parameters of the atrazine adsorption and degradation were obtained when the parameter of the hydrodynamic dispersion was determined from the data on the 18O migration. The simulation also showed that the use of parameters obtained at water content close to saturation in the calculations for an unsaturated soil resulted in the overestimation of the leaching rate and the maximum concentration of atrazine in the output curve compared to the experimental data.

Population structure of the African Clawed Frog (Xenopus laevis) in maize-growing areas with atrazine application versus non-maize-growing areas in South Africa

USGS Publications Warehouse

Du Preez, L.H.; Solomon, K.R.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Weldon, C.

2005-01-01

The herbicide atrazine has been suggested to cause gonadal deformities in frogs and could possibly impact on reproduction. Since the early 1960s, atrazine has been used in large amounts in maize production areas of South Africa. These areas overlap with populations of the African Clawed Frog (Xenopus laevis) that has a wide distribution in southern Africa and is found in most water-bodies including those where atrazine residues are detected. The aim of this study was to compare various attributes of individual- and population-level responses of X. laevis from maize-growing and non-maize-growing areas. Xenopus laevis were studied in three reference and five maize-growing sites. Sex ratio, snout-vent length, body-mass and age profiles were found to be similar for populations in maize-growing and non-maize-growing areas. Our mark-recapture data indicated that all sites had robust populations. There were no significant relationships between exposure to atrazine and any of the parameters investigated in populations of X. laevis.

Biodegradation of atrazine from wastewater using moving bed biofilm reactor under nitrate-reducing conditions: A kinetic study.

PubMed

Derakhshan, Zahra; Ehrampoush, Mohammad Hassan; Mahvi, Amir Hossein; Ghaneian, Mohammad Taghi; Mazloomi, Seyed Mohammad; Faramarzian, Mohammad; Dehghani, Mansooreh; Fallahzadeh, Hossein; Yousefinejad, Saeed; Berizi, Enayat; Bahrami, Shima

2018-04-15

In this study employed an anoxic moving bed biofilm reactor (AnMBBR) to evaluate the effects of hydraulic and toxic shocks on performance reactor. The results indicated a relatively good resistance of system against exercised shocks and its ability to return to steady-state conditions. In optimal conditions when there was the maximum rate of atrazine and soluble chemical oxygen demand (COD) removal were 74.82% and 99.29% respectively. Also, atrazine biodegradation rapidly declines in AnMBBR from 74% ± 0.05 in the presence of nitrate to 9.12% only 3 days after the nitrate was eliding from the influent. Coefficients kinetics was studied and the maximum atrazine removal rate was determined by modified Stover & Kincannon model (U max  = 9.87 g ATZ /m 3 d). Results showed that AnMBBR is feasible, easy, affordable, so suitable process for efficiently biodegrading toxic chlorinated organic compounds such as atrazine. Also, its removal mechanism in this system is co-metabolism. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biochar-supported reduced graphene oxide composite for adsorption and coadsorption of atrazine and lead ions

NASA Astrophysics Data System (ADS)

Zhang, Ying; Cao, Bo; Zhao, Lulu; Sun, Lili; Gao, Yan; Li, Jiaojiao; Yang, Fan

2018-01-01

To explore potential in application for simultaneous removal of atrazine and lead ions (Pd2+), the adsorption and coadsorption of atrazine and Pd2+ is evaluated onto a novel biochar-supported reduced graphene oxide composite (RGO-BC), which has been successfully developed via slow pyrolysis of graphene oxide (GO) pretreated corn straws. Structure and morphology analysis reveal that GO nanosheets are coated on the surface of biochar (BC) mainly through π-π interactions, notably, GO nanosheets after annealing reduction can basically retain the original morphology, meanwhile, the change of physico-chemical properties on the surface endow excellent adsorption capaities of 26.10 mg g-1 for Pb2+ and 67.55 mg g-1 for atrazine. A significant difference is in sorption of Pb2+ and atrazine on RGO-BC sample in both single- and binary-solute systems. The adsorption capacity of RGO-BC still remained above 54.58 mg g-1 after four times regeneration (81% adsorption capacity remained), demonstrating a promising candidate for the application of removal contaminant in the environment.

Enzymatic vegetable organic extracts as soil biochemical biostimulants and atrazine extenders.

PubMed

García-Martínez, Ana María; Tejada, Manuel; Díaz, Ana Isabel; Rodríguez-Morgado, Bruno; Bautista, Juan; Parrado, Juan

2010-09-08

The purpose of this study was to gather information on the potential effects of organic biostimulants on soil activity and atrazine biodegradation. Carob germ enzymatic extract (CGEE) and wheat condensed distiller solubles enzymatic extract (WCDS-EE) have been obtained using an enzymatic process; their main organic components are soluble carbohydrates and proteins in the form of peptides and free amino acids. Their application to soil results in high biostimulation, rapidly increased dehydrogenase, phosphatase and glucosidase activities, and an observed atrazine extender capacity due to inhibition of its mineralization. The extender capacity of both extracts is proportional to the protein/carbohydrate ratio content. As a result, these enzymatic extracts are highly microbially available, leading to two independent phenomena, fertility and an atrazine persistence that is linked to increased soil activity.

Effects of pulsed atrazine exposures on autotrophic community structure, biomass, and production in field-based stream mesocosms.

PubMed

King, Ryan S; Brain, Richard A; Back, Jeffrey A; Becker, Christopher; Wright, Moncie V; Djomte, Valerie Toteu; Scott, W Casan; Virgil, Steven R; Brooks, Bryan W; Hosmer, Alan J; Chambliss, C Kevin

2016-03-01

The authors performed a multiple-pulsed atrazine experiment to measure responses of autotrophic endpoints in outdoor stream mesocosms. The experiment was designed to synthetically simulate worst-case atrazine chemographs from streams in agricultural catchments to achieve 60-d mean concentrations of 0 μg/L (control), 10 μg/L, 20 μg/L, and 30 μg/L. The authors dosed triplicate streams with pulses of 0 μg/L, 50 μg/L, 100 μg/L, and 150 μg/L atrazine for 4 d, followed by 7 d without dosing. This 11-d cycle occurred 3 times, followed by a recovery (untreated) period from day 34 to day 60. Mean ± standard error 60-d atrazine concentrations were 0.07 ± 0.03 μg/L, 10.7 ± 0.05 μg/L, 20.9 ± 0.24 μg/L, and 31.0 ± 0.17 μg/L for the control, 10-μg/L, 20-μg/L, and 30-μg/L treatments, respectively. Multivariate analyses revealed that periphyton and phytoplankton community structure did not differ among treatments on any day of the experiment, including during the atrazine pulses. Control periphyton biomass in riffles was higher immediately following the peak of the first atrazine pulse and remained slightly higher than some of the atrazine treatments on most days through the peak of the last pulse. However, periphyton biomass was not different among treatments at the end of the present study. Phytoplankton biomass was not affected by atrazine. Metaphyton biomass in pools was higher in the controls near the midpoint of the present study and remained higher on most days for the remainder of the study. Ceratophyllum demersum, a submersed macrophyte, biomass was higher in controls than in 20-μg/L and 30-μg/L treatments before pulse 3 but was not different subsequent to pulse 3 through the end of the present study. Maximum daily dissolved oxygen (DO, percentage of saturation) declined during each pulse in approximate proportion to magnitude of dose but rapidly converged among treatments after the third pulse. However, DO increased in controls relative to all atrazine treatments during the last 17 d of the experiment, likely a result of metaphyton cover in the pools. Finally, atrazine significantly limited uptake of PO4(3-) and uptake and/or denitrification of NO3(-) but only during pulses; percentage of dose removed from the water column was >85% for P and >95% for N after pulse 3 through the end of the present study. Collectively, only DO and metaphyton biomass differed at the end of the present study and only slightly. Some other endpoints were affected but only during pulses, if at all. The high levels of primary production and accumulation of algal biomass in all streams suggest that effects of pulses of atrazine at the concentrations used in the present study appear transient and likely do not represent ecologically significant adverse outcomes to periphyton, phytoplankton, and aquatic macrophytes, particularly in agricultural streams subjected to high nutrient loads. © 2015 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

LACEwING: A New Moving Group Analysis Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riedel, Adric R.; Blunt, Sarah C.; Faherty, Jacqueline K.

We present a new nearby young moving group (NYMG) kinematic membership analysis code, LocAting Constituent mEmbers In Nearby Groups (LACEwING), a new Catalog of Suspected Nearby Young Stars, a new list of bona fide members of moving groups, and a kinematic traceback code. LACEwING is a convergence-style algorithm with carefully vetted membership statistics based on a large numerical simulation of the Solar Neighborhood. Given spatial and kinematic information on stars, LACEwING calculates membership probabilities in 13 NYMGs and three open clusters within 100 pc. In addition to describing the inputs, methods, and products of the code, we provide comparisons ofmore » LACEwING to other popular kinematic moving group membership identification codes. As a proof of concept, we use LACEwING to reconsider the membership of 930 stellar systems in the Solar Neighborhood (within 100 pc) that have reported measurable lithium equivalent widths. We quantify the evidence in support of a population of young stars not attached to any NYMGs, which is a possible sign of new as-yet-undiscovered groups or of a field population of young stars.« less

Application of a geographic information system in analyzing the occurrence of atrazine in groundwater of the mid-continental United States

USGS Publications Warehouse

Burkart, M.R.; Kolpin, D.W.

1993-01-01

The US Geological Survey, US Department of Agriculture, and US Environmental Protection Agency are conducting research and regional assessments in support of policy alternatives intended to protect water resources from agricultural chemical contamination. The mid-continent was selected because of the intense row crop agriculture and associated herbicide application in this region. An application of a geographic information system is demonstrated for analyzing and comparing the distribution of estimated atrazine use to the detection rate of atrazine in groundwater. Understanding the relations between atrazine use and detection in groundwater is important in policy deliberations to protect water resources. Relational analyses between measures of chemical use and detection rate by natural resource units may provide insight into critical factors controlling the processes that result in groundwater contamination from agricultural chemicals. 

Atrazine concentrations in near-surface aquifers: A censored regression approach

USGS Publications Warehouse

Liu, S.; Yen, S.T.; Kolpin, D.W.

1996-01-01

In 1991, the U.S. Geological Survey (USGS) conducted a study to investigate the occurrence of atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) and other agricultural chemicals in near-surface aquifers in the midcontinental USA. Because about 83% of the atrazine concentrations from the USGS study were censored, standard statistical estimation procedures could not be used. To determine factors that affect atrazine concentrations in groundwater while accommodating the high degree of data censoring. Tobit models were used (normal homoscedastic, normal heteroscedastic, lognormal homoscedastic, and lognormal heteroscedastic). Empirical results suggest that the lognormal heteroscedastic Tobit model is the model of choice for this type of study. This model determined the following factors to have the strongest effect on atrazine concentrations in groundwater: percent of pasture within 3.2 km, percent of forest within 3.2 km (2 mi), mean open interval of the well, primary water use of a well, aquifer class (unconsolidated or bedrock), aquifer type (unconfined or confined), existence of a stream within 30 m (100 ft), existence of a stream within 30 m to 0.4 km (0.25 mi), and existence of a stream within 0.4 to 3.2 km. Examining the elasticities of the continuous explanatory factors provides further insight into their effects on atrazine concentrations in groundwater. This study documents a viable statistical method that can be used to accommodate the complicating presence of censured data, a feature that commonly occurs in environmental data.

Lethal and Sublethal Effects of the Herbicide Atrazine in the Early Stages of Development of Physalaemus gracilis (Anura: Leptodactylidae).

PubMed

Rutkoski, Camila F; Macagnan, Natani; Kolcenti, Cassiane; Vanzetto, Guilherme V; Sturza, Paola F; Hartmann, Paulo A; Hartmann, Marilia T

2018-05-01

Water sources used as reproductive sites by crying frog, Physalaemus gracilis, are extensively associated with agroecosystems in which the herbicide atrazine is employed. To evaluate the lethal and sublethal effects of atrazine commercial formulation, acute and chronic toxicity tests were performed in the embryonic phase and the beginning of the larval phase of P. gracilis. Tests were started on stage 19 of Gosner (Herpetologica 16:183-190, 1960) and performed in 24-well cell culture plates. Acute tests had a duration of 96 h with embryo mortality monitoring every 24 h. Chronic assays contemplated the transition from the embryonic to larval stages and lasted 168 h. Every 24 h the embryos/larvae were observed for mortality, mobility, and malformations. The LC50 of atrazine determined for P. gracilis embryos was 229.34 mg L -1 . The sublethal concentrations did not affect the development of the larvae but were observed effects on mobility and malformations, such as spasmodic contractions, reduced mobility, malformations in mouth and intestine, and edema arising. From 1 mg L -1 atrazine, the exposed larvae began to have changes in mobility and malformations. The atrazine commercial formulation has caused early life effects of P. gracilis that may compromise the survival of this species but at higher concentrations than recorded in the environment, so P. gracilis can be considered tolerant to this herbicide at environmentally relevant concentrations.

Transport of atrazine versus bromide and δO18 in sand

USGS Publications Warehouse

Tindall, James A.; Friedel, Michael J.

2016-01-01

The objective of this research was to determine the process of atrazine transport compared to bromide and δO18 transport in sands near Denver. Three 1.5 × 2 × 1.5-m plots were installed and allowed to equilibrate for 2 years before research initiation and were instrumented with 1.5 × 2-m zero-tension pan lysimeters installed at 1.5-m depths. Additionally, each plot was instrumented with suction lysimeters, tensiometers, time domain reflectometry (TDR) moisture probes, and thermocouples (to measure soil temperature) at 15-cm depth increments. All plots were enclosed with a raised frame (of 8-cm height) to prevent surface runoff. During the 2-year period before research began, all suction and pan lysimeters were purged monthly and were sampled for fluids immediately prior to atrazine and KBr application to obtain background concentrations. Atrazine illustrated little movement until after a significant rainfall event, which peaked concentrations at depths of about 90 to 135 cm. Both Br− and δO18 moved rapidly through the soil, probably owing to soil porosity and anion exclusion for Br−. Concentrations of atrazine exceeding 5.0 μL−1 were observed with depth (90 to 150 cm) after several months. It appears that significant rainfall events were a key factor in the movement of atrazine in the sand, which allowed the chemicals to move to greater depths and thus avoid generally found biodegradation processes.

Fish short-term reproduction assay with atrazine and the Japanese medaka (Oryzias latipes).

PubMed

Hosmer, Alan J; Schneider, Suzanne Z; Anderson, Julie C; Knopper, Loren D; Brain, Richard A

2017-09-01

Breeding groups of Japanese medaka (Oryzias latipes) were exposed to atrazine at measured concentrations of 0.6, 5.5, and 53 μg/L for 35 d. Evaluated endpoints included survival, fecundity, fertility, growth (weight and length), behavior, secondary sex characteristics (anal fin papillae), gonad histopathology, and hepatic vitellogenin. No statistically significant effects of atrazine exposure on survival and growth of medaka were noted during the test, and mean survival was ≥97.5% in all treatment groups on day 35. No significant effects of atrazine exposure on reproduction were observed. The number of mean cumulative eggs produced in the negative control and the 0.6, 5.5, and 53 μg/L treatment groups was 7158, 6691, 6883, and 6856, respectively. The mean number of eggs per female reproductive day was 40.9, 38.2, 40.2, and 39.2, respectively. There were also no dose-dependent effects on mean anal fin papillae counts among male fish or expression of vtg-II in males or females. In addition, atrazine exposure was not related to the developmental stage of test fish, with testes stages ranging from 2 to 3 in all groups and ovaries ranging from stage 2 to 2.5. Overall, exposure to atrazine up to 53 µg/L for 35 d did not result in significant, treatment-related effects on measured endpoints related to survival, growth, or reproduction in Japanese medaka. Environ Toxicol Chem 2017;36:2327-2334. © 2017 SETAC. © 2017 SETAC.

Tribology and Friction of Soft Materials: Mississippi State Case Study

DTIC Science & Technology

2010-03-18

elastomers , foams, and fabrics. B. Develop internal state variable (ISV) material model. Model will be calibrated using database and verified...Rubbers Natural rubber Santoprene (Vulcanized Elastomer ) Styrene Butadiene Rubber (SBR) Foams Polypropylene Foam Polyurethane Foam Fabrics Kevlar...Axially symmetric model PC Disk PC Numerical Implementation in FEM Codes Experiment SEM Optical methods ISV Model Void Nucleation FEM Analysis

Atrazine and Diuron partitioning within a soil-water-surfactant system

NASA Astrophysics Data System (ADS)

Wang, P.; Keller, A.

2006-12-01

The interaction between pesticide and soil and water is even more complex in the presence of surfactants. In this study, batch equilibrium was employed to study the sorption of surfactants and the partitioning behaviors of Atrazine and Diuron within a soil-water-surfactant system. Five soils and four surfactants (nonionic Triton- 100, cationic Benzalkonium Chloride (BC), anionic Linear Alkylbenzenesulfonate (LAS), and anionic Sodium Dodecyl Sulfate (SDS)) were used. All surfactant sorption isotherms exhibited an initial linear increase at low surfactant concentrations but reached an asymptotic value as the surfactant concentrations increased. Among the surfactants, BC had the highest sorption onto all soils, followed by Triton-100 and then by LAS and SDS, implying that the nature of the charge significantly influences surfactant sorption. Sorption of either Triton-100 or BC was highly correlated with soil Cation Exchange Capacity (CEC) while that of LAS and SDS was complicated by the presence of Ca2+ and Mg2+ in the aqueous phase and the CEC sites. Both LAS and SDS formed complexes with Ca2+ and Mg2+, resulting in a significant decrease in the detergency of the surfactants. At high surfactant concentrations and with micelles present in the aqueous phase, the micelles formed a more competitive partitioning site for the pesticides, resulting in less pesticide sorbed to the soil. At low Triton-100 and BC concentration, the sorption of the surfactants first resulted in less Atrazine sorption but more Diuron sorption, implying competition between the surfactants and Atrazine, which serves as an indirect evidence that there is a different sorption mechanism for Atrazine. Atrazine is a weak base and it protonates and becomes positively charged near particle surfaces where the pH is much lower than in the bulk solution. The protonated Atrazine may then be held on the CEC sites via electrostatic attraction. Triton-100, LAS and SDS sorbed on the soil showed similar sequestration efficiency for Atrazine and Diuron while BC sorbed on the soils with lower CECs showed much higher Atrazine and Diuron sequestration efficiency than the other surfactants, suggesting that the sorbed BC on these soils with less CEC forms bulk-like partitioning media more easily than the soils with higher CECs. These results significantly improve our understanding of partitioning of pesticides within soil-water-surfactant systems. These findings can serve to improve the pesticide removal efficiency of soil washing systems. Also, our results show that by studying the effect of surfactants on pesticide sorption can serve as a new method to study pesticide sorption mechanisms.

Method for Estimating Annual Atrazine Use for Counties in the Conterminous United States, 1992-2007

USGS Publications Warehouse

Thelin, Gail P.; Stone, Wesley W.

2010-01-01

A method was developed to estimate annual atrazine use during 1992 to 2007 on sixteen crops and four agricultural land uses. For each year, atrazine use was estimated for all counties in the conterminous United States (except California) by combining (1) proprietary data from the Doane Marketing Research-Kynetec (DMRK) AgroTrak database on the mass of atrazine applied to agricultural crops, (2) county harvested crop acreage, by county, from the 1992, 1997, 2002, and 2007 Censuses of Agriculture, and (3) annual harvested crop acreage from National Agriculture Statistics Service (NASS) for non-Census years. DMRK estimates of pesticide use on individual crops were derived from surveys of major field crops and selected specialty crops in multicounty areas referred to as Crop Reporting Districts (CRD). The CRD-level atrazine-use estimates were disaggregated to obtain county-level application rates by dividing the mass (pounds) of pesticides applied to a crop by the acreage of that crop in the CRD to yield a rate per harvested acre. When atrazine-use estimates were not available for a CRD, crop, or year, an estimated rate was developed following a hierarchy of decision rules that checked first for the availability of a crop application rate from surveyed atrazine application rate(s) for adjacent CRDs for a specific year, and second, the rates from surveyed CRDs within for U.S. Department of Agriculture Farm Production Regions for a specific year or multiple years. The estimation method applied linear interpolation to estimate crop acreage for years when harvested acres for a crop and county were not reported in either the Census of Agriculture or the NASS database, but were reported by these data sources for other years for that crop and county. Data for atrazine use for the counties in California was obtained from farmers' reports of pesticide use collected and published by the California Department of Pesticide Regulation-Pesticide Use Reporting (DPR-PUR) because these data are more complete than DMRK survey data. National and state annual atrazine-use totals derived by this method were compared with other published pesticide-use estimates and were highly correlated. The method developed is designed to be applicable to other pesticides for which there are similar data; however, for some pesticides that are applied to specialty crops, fewer surveys are usually available to estimate application rates and there are a greater number of years with unreported crop acreage, potentially resulting in greater uncertainty in use

Distributed polar-coded OFDM based on Plotkin's construction for half duplex wireless communication

NASA Astrophysics Data System (ADS)

Umar, Rahim; Yang, Fengfan; Mughal, Shoaib; Xu, HongJun

2018-07-01

A Plotkin-based polar-coded orthogonal frequency division multiplexing (P-PC-OFDM) scheme is proposed and its bit error rate (BER) performance over additive white gaussian noise (AWGN), frequency selective Rayleigh, Rician and Nakagami-m fading channels has been evaluated. The considered Plotkin's construction possesses a parallel split in its structure, which motivated us to extend the proposed P-PC-OFDM scheme in a coded cooperative scenario. As the relay's effective collaboration has always been pivotal in the design of cooperative communication therefore, an efficient selection criterion for choosing the information bits has been inculcated at the relay node. To assess the BER performance of the proposed cooperative scheme, we have also upgraded conventional polar-coded cooperative scheme in the context of OFDM as an appropriate bench marker. The Monte Carlo simulated results revealed that the proposed Plotkin-based polar-coded cooperative OFDM scheme convincingly outperforms the conventional polar-coded cooperative OFDM scheme by 0.5 0.6 dBs over AWGN channel. This prominent gain in BER performance is made possible due to the bit-selection criteria and the joint successive cancellation decoding adopted at the relay and the destination nodes, respectively. Furthermore, the proposed coded cooperative schemes outperform their corresponding non-cooperative schemes by a gain of 1 dB under an identical condition.

Immobilization of the white-rot fungus Anthracophyllum discolor to degrade the herbicide atrazine.

PubMed

Elgueta, S; Santos, C; Lima, N; Diez, M C

2016-12-01

Herbicides cause environmental concerns because they are toxic and accumulate in the environment, food products and water supplies. There is a need to develop safe, efficient and economical methods to remove them from the environment, often by biodegradation. Atrazine is such herbicide. White-rot fungi have the ability to degrade herbicides of potential utility. This study formulated a novel pelletized support to immobilize the white-rot fungus Anthracophyllum discolor to improve its capability to degrade the atrazine using a biopurification system (BS). Different proportions of sawdust, starch, corn meal and flaxseed were used to generate three pelletized supports (F1, F2 and F3). In addition, immobilization with coated and uncoated pelletized supports (CPS and UPS, respectively) was assessed. UPS-F1 was determined as the most effective system as it provided high level of manganese peroxidase activity and fungal viability. The half-life (t 1/2 ) of atrazine decreased from 14 to 6 days for the control and inoculated samples respectively. Inoculation with immobilized A. discolor produced an increase in the fungal taxa assessed by DGGE and on phenoloxidase activity determined. The treatment improves atrazine degradation and reduces migration to surface and groundwater.

Bioremediation model for atrazine contaminated agricultural soils using phytoremediation (using Phaseolus vulgaris L.) and a locally adapted microbial consortium.

PubMed

Madariaga-Navarrete, Alfredo; Rodríguez-Pastrana, Blanca Rosa; Villagómez-Ibarra, José Roberto; Acevedo-Sandoval, Otilio Arturo; Perry, Gregory; Islas-Pelcastre, Margarita

2017-06-03

The objective of the present study was to examine a biological model under greenhouse conditions for the bioremediation of atrazine contaminated soils. The model consisted in a combination of phytoremediation (using Phaseolus vulgaris L.) and rhizopheric bio-augmentation using native Trichoderma sp., and Rhizobium sp. microorganisms that showed no inhibitory growth at 10,000 mg L -1 of herbicide concentration. 33.3 mg of atrazine 50 g -1 of soil of initial concentration was used and an initial inoculation of 1 × 10 9 UFC mL -1 of Rhizobium sp. and 1 × 10 5 conidia mL -1 of Trichoderma sp. were set. Four treatments were arranged: Bean + Trichoderma sp. (B+T); Bean + Rhizobium sp. (BR); Bean + Rhizobium sp. + Trichoderma sp. (B+R+T) and Bean (B). 25.51 mg of atrazine 50 g -1 of soil (76.63%) was removed by the B+T treatment in 40 days (a = 0.050, Tukey). This last indicate that the proposed biological model and methodology developed is useful for atrazine contaminated bioremediation agricultural soils, which can contribute to reduce the effects of agrochemical abuse.

Modeling pesticide fate in a small tidal estuary

USGS Publications Warehouse

McCarthy, A.M.; Bales, J.D.; Cope, W.G.; Shea, D.

2007-01-01

The exposure analysis modeling system (EXAMS), a pesticide fate model developed by the U.S. Environmental Protection Agency, was modified to model the fate of the herbicides atrazine and metolachlor in a small tidally dominated estuary (Bath Creek) in North Carolina, USA where freshwater inflow accounts for only 3% of the total flow. The modifications simulated the changes that occur during the tidal cycle in the estuary, scenarios that are not possible with the original EXAMS model. Two models were created within EXAMS, a steady-state model and a time-variant tidally driven model. The steady-state model accounted for tidal flushing by simply altering freshwater input to yield an estuary residence time equal to that measured in Bath Creek. The tidal EXAMS model explicitly incorporated tidal flushing by modifying the EXAMS code to allow for temporal changes in estuary physical attributes (e.g., volume). The models were validated with empirical measurements of atrazine and metolachlor concentrations in the estuary shortly after herbicide application in nearby fields and immediately following a rain event. Both models provided excellent agreement with measured concentrations. The steady-state EXAMS model accurately predicted atrazine concentrations in the middle of the estuary over the first 3 days and under-predicted metolachlor by a factor of 2-3. The time-variant, tidally driven EXAMS model accurately predicted the rise and plateau of both herbicides over the 6-day measurement period. We have demonstrated the ability of these modified EXAMS models to be useful in predicting pesticide fate and exposure in small tidal estuaries. This is a significant improvement and expansion of the application of EXAMS, and given the wide use of EXAMS for surface water quality modeling by both researchers and regulators and the ability of EXAMS to interface with terrestrial models (e.g., pesticide root zone model) and bioaccumulation models, we now have an easily-accessible and widely accepted means of modeling chemical fate in estuaries. ?? 2006 Elsevier B.V. All rights reserved.

A general formula for computing maximum proportion correct scores in various psychophysical paradigms with arbitrary probability distributions of stimulus observations.

PubMed

Dai, Huanping; Micheyl, Christophe

2015-05-01

Proportion correct (Pc) is a fundamental measure of task performance in psychophysics. The maximum Pc score that can be achieved by an optimal (maximum-likelihood) observer in a given task is of both theoretical and practical importance, because it sets an upper limit on human performance. Within the framework of signal detection theory, analytical solutions for computing the maximum Pc score have been established for several common experimental paradigms under the assumption of Gaussian additive internal noise. However, as the scope of applications of psychophysical signal detection theory expands, the need is growing for psychophysicists to compute maximum Pc scores for situations involving non-Gaussian (internal or stimulus-induced) noise. In this article, we provide a general formula for computing the maximum Pc in various psychophysical experimental paradigms for arbitrary probability distributions of sensory activity. Moreover, easy-to-use MATLAB code implementing the formula is provided. Practical applications of the formula are illustrated, and its accuracy is evaluated, for two paradigms and two types of probability distributions (uniform and Gaussian). The results demonstrate that Pc scores computed using the formula remain accurate even for continuous probability distributions, as long as the conversion from continuous probability density functions to discrete probability mass functions is supported by a sufficiently high sampling resolution. We hope that the exposition in this article, and the freely available MATLAB code, facilitates calculations of maximum performance for a wider range of experimental situations, as well as explorations of the impact of different assumptions concerning internal-noise distributions on maximum performance in psychophysical experiments.

Bioremediation of pesticide wastes in soil using two plant species, Kochia Scoparia and Brassica Napus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, E.L.; Anderson, T.A.; Coats, J.R.

1995-12-31

Radiotracer studies were conducted to determine the fate of atrazine and metolachlor, applied as a mixture, in soils taken from pesticide-contaminated sites. Samples taken from nonvegetated areas and from the rhizosphere of Kochia scoparia were treated with {sup 14}C-atrazine and unlabeled metolachlor (50 {mu}g/g each) and incubated for 30, 60 or 135 d. A mass balance of the {sup 14}C applied revealed significant differences between the two soil types in soil bound residues, {sup 14}CO{sub 2}, and the extractable organic fraction (p<0.05). After 135-d incubation, 28% of the applied {sup 14}C was mineralized in Kochia rhizosphere soil, compared to 4%more » in soil taken from a nonvegetated area. A greater amount of {sup 14}C was extractable from the nonvegetated soil compared to the rhizosphere soil (64% and 22%, respectively). The half-life of atrazine based on extractable {sup 14}C-atrazine was 193 d in nonvegetated soil and 50 d in Kochia rhizosphere soil. Additional subsamples of nonvegetated soils treated with a mixture of {sup 14}C-atrazine and metolachlor were allowed to age for 135 d, and then were either planted with Brassica napus, Kochia scoparia, or left unvegetated. Incubations were carried out in enclosed chambers under controlled conditions. After 30 additional days, a subset of samples was extracted and analyzed using thin-layer chromatography, soil and plant combustion, and liquid scintillation spectroscopy. The percent of applied {sup 14}C-atrazine remaining as atrazine in soil which was nonvegetated, or planted with Brassica napus or Kochia scoparia was 9.3, 6.5, and 4.2%, respectively. Combustion of plants revealed that 11% of the applied radioactivity was taken up in Kochia scoparia, while less than 1% was taken up in Brassica napus plants. The potential for vegetation to aid in bioremediating pesticide wastes in soil is promising.« less

Development and testing of method for assessing and mapping agricultural areas susceptible to atrazine leaching in the state of Washington

USGS Publications Warehouse

Voss, Frank D.

2003-01-01

In a joint effort by the Washington State Department of Agriculture, the Washington Department of Ecology, and the U.S. Geological Survey, the Environmental Protection Agency's Pesticide Root Zone Model and a Geographic Information System were used to develop and test a method for screening and mapping the susceptibility of ground water in agricultural areas to pesticide contamination. The objective was to produce a map that would be used by the Washington State Department of Agriculture to allocate resources for monitoring pesticide levels in ground water. The method was tested by producing a map showing susceptibility to leaching of the pesticide atrazine for the Columbia Basin Irrigation Project, which encompasses an area of intensive agriculture in eastern Washington. The reliability of the atrazine map was assessed by using statistical procedures to determine whether the median of the percentage of atrazine simulated to leach below the root zone in wells where atrazine was detected was statistically greater than the median percentage at wells where atrazine was not detected (at or above 0.001 microgram per liter) in 134 wells sampled by the U.S. Geological Survey. A statistical difference in medians was not found when all 134 wells were compared. However, a statistical difference was found in medians for two subsets of the 134 wells that were used in land-use studies (studies examining the quality of ground water beneath specific crops). The statistical results from wells from the land-use studies indicate that the model potentially can be used to map the relative susceptibility of agricultural areas to atrazine leaching. However, the distinction between areas of high and low susceptibility may not yet be sufficient to use the method for allocating resources to monitor water quality. Several options are offered for improving the reliability of future simulations.

Atrazine

Integrated Risk Information System (IRIS)

Atrazine ; CASRN 1912 - 24 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

Characterization of the hydrogeology and water quality at the Management Systems Evaluation Area near Princeton, Minnesota, 1991-92

USGS Publications Warehouse

Delin, G.N.; Landon, M.K.; Lamb, J.A.; Anderson, J.L.

1994-01-01

Atrazine was detected by gas chromatography mass spectroscopy in 2 of the 7 wells in the research area at concentrations of 0.04 and 0.17 micrograms per liter (ug/L), well below the U.S. Environmental Protection Agency's recommended maximum contaminant level of 3 ug/L. The median concentration in these Wells was less than the qualitative detection limit of 0.01 ug/L. Atrazine metabolite de-ethylatrazine was the most frequently detected herbicide or herbicide metabolite. De-ethylatrazine was detected in 5 of the 7 wells in the research area at concentrations ranging from 0.12 to 0.32 ug/L with a median concentration of 0.14 ug/L. Atrazine metabolite de-isopropylatrazine was not detected above the qualitative detection limit of 0.06 ug/L. The most likely sources of atrazine are applications to the research area during 1990 or from precipitation.

Stimulation at Desert Peak -modeling with the coupled THM code FEHM

DOE Data Explorer

kelkar, sharad

2013-04-30

Numerical modeling of the 2011 shear stimulation at the Desert Peak well 27-15. This submission contains the FEHM executable code for a 64-bit PC Windows-7 machine, and the input and output files for the results presented in the included paper from ARMA-213 meeting.

Augmenting atrazine and hexachlorobenzene degradation under different soil redox conditions in a bioelectrochemistry system and an analysis of the relevant microorganisms.

PubMed

Wang, Hui; Cao, Xian; Li, Lei; Fang, Zhou; Li, Xianning

2018-01-01

Soil microbial fuel cells (MFCs) are a sustainable technology that degrades organic pollutants while generating electricity. However, there have been no detailed studies of the mechanisms of pollutant degradation in soil MFCs. In this study, the effects of external resistance and electrode effectiveness on atrazine and hexachlorobenzene (HCB) degradation were evaluated, the performance of soil MFCs in the degradation of these pollutants under different soil redox conditions was assessed, and the associated microorganisms in the anode were investigated. With an external resistance of 20Ω, the degradation efficiencies of atrazine and HCB were 95% and 78%, respectively. The degradation efficiency, degradation rate increased with decreasing external resistance, while the half-life decreased. There were different degradation trends for different pollutants under different soil redox conditions. The fastest degradation rate of atrazine was in the upper MFC section (aerobic), whereas that of HCB was in the lower MFC section (anaerobic). The results showed that electrode effectiveness played a significant role in pollution degradation. In addition, the microbial community analysis demonstrated that Proteobacteria, especially Deltaproteobacteria involved in current generation was extremely abundant (27.49%) on soil MFC anodes, although the percentage abundances of atrazine degrading Rhodocyclaceae (8.77%), Desulfitobacterium (0.64%), and HCB degrading Desulfuromonas (0.73%), were considerably lower. The results of the study suggested that soil MFCs can enhance the degradation of atrazine and HCB, and bioelectrochemical reduction was the main mechanism for the pollutants degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

Bioremediation strategies for pesticide-contaminated sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaplin-Anhalt, J.A.; Anderson, T.A.; Perkovich, B.S.

1995-12-31

As the number of pesticide-contaminated sites at places such as agrochemical dealerships continues to grow there is an urgent need to find methods of remediation. Soils from two pesticide-contaminated sites, Alpha and Bravo, were analyzed using gas chromatography. The contaminants and their concentrations ({mu}g/g) were as follows: atrazine (0.1 to 24), metolachlor (2 to 121), trifluralin (1 to 244), and pendimethalin (5 to 334). A radiotracer study was conducted to determine the fate of a combined application of atrazine and metolachlor at a concentration of 50 {mu}g/g each. The mixture was applied to Alpha and Bravo nonvegetated soils and Kochiamore » scoparia rhizosphere soils. After 30 d incubation in Bravo soil, mineralization of metolachlor was minimal with less than 1% recovered as {sup 14}CO{sub 2}. Metolachlor degradation in the rhizosphere soil was greater than in nonvegetated soils with 56% and 100% of metolachlor remaining, respectively, after 30 d. Atrazine mineralization was as high as 62% of the applied {sup 14}C. Additional soil from Bravo was treated with 50 {mu}g/g of unlabeled atrazine. The soil was divided into three treatments and a control with three replicates each. Each treatment involved inoculation of 100 g of Bravo soil with 2 g from one of three soils determined in our laboratory to have enhanced atrazine degradative capabilities. Soils were incubated for 15 or 35 d. The soils will be analyzed by gas chromatography to determine which, if any, of the inoculants increase the degradation of atrazine.« less

Biomarker analysis of American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles following exposure to atrazine.

PubMed

Snyder, Marcía N; Henderson, W Matthew; Glinski, Donna A; Purucker, S Thomas

2017-01-01

The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environmental matrices throughout the United States. In surface waters, it has been found at concentrations from 0.04-2859μg/L and thus presents a likely exposure scenario for non-target species such as amphibians. Studies have examined the effect of atrazine on the metamorphic parameters of amphibians, however, the data are often contradictory. Gosner stage 22-24 tadpoles were exposed to 0 (control), 10, 50, 250 or 1250μg/L of atrazine for 48h. Endogenous polar metabolites were extracted and analyzed using gas chromatography coupled with mass spectrometry. Statistical analyses of the acquired spectra with machine learning classification models demonstrated identifiable changes in the metabolomic profiles between exposed and control tadpoles. Support vector machine models with recursive feature elimination created a more efficient, non-parametric data analysis and increased interpretability of metabolomic profiles. Biochemical fluxes observed in the exposed groups of both A. americanus and H. versicolor displayed perturbations in a number of classes of biological macromolecules including fatty acids, amino acids, purine nucleosides, pyrimidines, and mono- and di-saccharides. Metabolomic pathway analyses are consistent with findings of other studies demonstrating disruption of amino acid and energy metabolism from atrazine exposure to non-target species. Copyright © 2016. Published by Elsevier B.V.

Influence of organic matter, nutrients, and cyclodextrin on microbial and chemical herbicide and degradate dissipation in subsurface sediment slurries.

PubMed

Kerminen, Kaisa; Le Moël, Romain; Harju, Vilhelmiina; Kontro, Merja H

2018-03-15

Pesticides leaching from soil to surface and groundwater are a global threat for drinking water safety, as no cleaning methods occur for groundwater environment. We examined whether peat, compost-peat-sand (CPS) mixture, NH 4 NO 3 , NH 4 NO 3 with sodium citrate (Na-citrate), and the surfactant methyl-β-cyclodextrin additions enhance atrazine, simazine, hexazinone, dichlobenil, and the degradate 2,6-dichlorobenzamide (BAM) dissipations in sediment slurries under aerobic and anaerobic conditions, with sterilized controls. The vadose zone sediment cores were drilled from a depth of 11.3-14.6m in an herbicide-contaminated groundwater area. The peat and CPS enhanced chemical atrazine and simazine dissipation, and the peat enhanced chemical hexazinone dissipation, all oxygen-independently. Dichlobenil dissipated under all conditions, while BAM dissipation was fairly slow and half-lives could not be calculated. The chemical dissipation rates could be associated with the chemical structures and properties of the herbicides, and additive compositions, not with pH. Microbial atrazine degradation was only observed in the Pseudomonas sp. ADP amended slurries, although the sediment slurries were known to contain atrazine-degrading microorganisms. The bioavailability of atrazine in the water phase seemed to be limited, which could be due to complex formation with organic and inorganic colloids. Atrazine degradation by indigenous microbes could not be stimulated by the surfactant methyl-β-cyclodextrin, or by the additives NH 4 NO 3 and NH 4 NO 3 with Na-citrate, although the nitrogen additives increased microbial growth. Copyright © 2017 Elsevier B.V. All rights reserved.

Agriculture-related trends in groundwater quality of the glacial deposits aquifer, central Wisconsin

USGS Publications Warehouse

Saad, D.A.

2008-01-01

Measuring and understanding trends in groundwater quality is necessary for determining whether changes in land-management practices have an effect on groundwater quality. This paper describes an approach that was used to measure and understand trends using data from two groundwater studies conducted in central Wisconsin as part of the USGS NAWQA program. One of the key components of this approach, determining the age of sampled groundwater, gave a temporal component to the snapshots of water quality that were obtained through synoptic-sampling efforts. This approach can be used at other locations where groundwater quality data are collected, groundwater age can be determined, and associated temporal data are available. Results of these studies indicate measured concentrations of nitrate and atrazine plus deethylatrazine were correlated to historical patterns of fertilizer and atrazine use. Concentrations of nitrate in groundwater have increased over time; concentrations of atrazine plus deethylatrazine increased and then decreased. Concentrations of nitrate also were correlated to screen depth below the water level and concentrations of dissolved O2; concentrations of atrazine plus deethylatrazine were correlated to dissolved O2 and annual precipitation. To measure trends in concentrations of atrazine plus deethylatrazine, the data, collected over a near-decadal period, were adjusted to account for changes in laboratory-reporting levels and analytical recoveries. Only after accounting for these changes was it apparent that the median concentrations of atrazine plus deethylatrazine decreased over the near-decadal interval between sampling efforts. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

ELIPGRID-PC: A PC program for calculating hot spot probabilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, J.R.

1994-10-01

ELIPGRID-PC, a new personal computer program has been developed to provide easy access to Singer`s 1972 ELIPGRID algorithm for hot-spot detection probabilities. Three features of the program are the ability to determine: (1) the grid size required for specified conditions, (2) the smallest hot spot that can be sampled with a given probability, and (3) the approximate grid size resulting from specified conditions and sampling cost. ELIPGRID-PC also provides probability of hit versus cost data for graphing with spread-sheets or graphics software. The program has been successfully tested using Singer`s published ELIPGRID results. An apparent error in the original ELIPGRIDmore » code has been uncovered and an appropriate modification incorporated into the new program.« less

Indicators: Atrazine

EPA Pesticide Factsheets

Atrazine is an herbicide widely used for control of broadleaf and grassy weeds. It is sprayed on row crops such as corn, sorghum and sugarcane, and in some areas is used on residential lawns. It also been used on highway and railroad rights-of-way.

Phase precession through acceleration of local theta rhythm: a biophysical model for the interaction between place cells and local inhibitory neurons.

PubMed

Castro, Luísa; Aguiar, Paulo

2012-08-01

Phase precession is one of the most well known examples within the temporal coding hypothesis. Here we present a biophysical spiking model for phase precession in hippocampal CA1 which focuses on the interaction between place cells and local inhibitory interneurons. The model's functional block is composed of a place cell (PC) connected with a local inhibitory cell (IC) which is modulated by the population theta rhythm. Both cells receive excitatory inputs from the entorhinal cortex (EC). These inputs are both theta modulated and space modulated. The dynamics of the two neuron types are described by integrate-and-fire models with conductance synapses, and the EC inputs are described using non-homogeneous Poisson processes. Phase precession in our model is caused by increased drive to specific PC/IC pairs when the animal is in their place field. The excitation increases the IC's firing rate, and this modulates the PC's firing rate such that both cells precess relative to theta. Our model implies that phase coding in place cells may not be independent from rate coding. The absence of restrictive connectivity constraints in this model predicts the generation of phase precession in any network with similar architecture and subject to a clocking rhythm, independently of the involvement in spatial tasks.

Application of Quaternion in improving the quality of global sequence alignment scores for an ambiguous sequence target in Streptococcus pneumoniae DNA

NASA Astrophysics Data System (ADS)

Lestari, D.; Bustamam, A.; Novianti, T.; Ardaneswari, G.

2017-07-01

DNA sequence can be defined as a succession of letters, representing the order of nucleotides within DNA, using a permutation of four DNA base codes including adenine (A), guanine (G), cytosine (C), and thymine (T). The precise code of the sequences is determined using DNA sequencing methods and technologies, which have been developed since the 1970s and currently become highly developed, advanced and highly throughput sequencing technologies. So far, DNA sequencing has greatly accelerated biological and medical research and discovery. However, in some cases DNA sequencing could produce any ambiguous and not clear enough sequencing results that make them quite difficult to be determined whether these codes are A, T, G, or C. To solve these problems, in this study we can introduce other representation of DNA codes namely Quaternion Q = (PA, PT, PG, PC), where PA, PT, PG, PC are the probability of A, T, G, C bases that could appear in Q and PA + PT + PG + PC = 1. Furthermore, using Quaternion representations we are able to construct the improved scoring matrix for global sequence alignment processes, by applying a dot product method. Moreover, this scoring matrix produces better and higher quality of the match and mismatch score between two DNA base codes. In implementation, we applied the Needleman-Wunsch global sequence alignment algorithm using Octave, to analyze our target sequence which contains some ambiguous sequence data. The subject sequences are the DNA sequences of Streptococcus pneumoniae families obtained from the Genebank, meanwhile the target DNA sequence are received from our collaborator database. As the results we found the Quaternion representations improve the quality of the sequence alignment score and we can conclude that DNA sequence target has maximum similarity with Streptococcus pneumoniae.

Nanoporous impedemetric biosensor for detection of trace atrazine from water samples.

PubMed

Pichetsurnthorn, Pie; Vattipalli, Krishna; Prasad, Shalini

2012-02-15

Trace contamination of ground water sources has been a problem ever since the introduction of high-soil-mobility pesticides, one such example is atrazine. In this paper we present a novel nanoporous portable bio-sensing device that can identify trace contamination of atrazine through a label-free assay. We have designed a pesticide sensor comprising of a nanoporous alumina membrane integrated with printed circuit board platform. Nanoporous alumina in the biosensor device generates a high density array of nanoscale confined spaces. By leveraging the size based immobilization of atrazine small molecules we have designed electrochemical impedance spectroscopy based biosensor to detect trace amounts of atrazine. We have calibrated the sensor using phosphate buffered saline and demonstrated trace detection from river and bottled drinking water samples. The limit of detection in all the three cases was in the femtogram/mL (fg/mL) (parts-per-trillion) regime with a dynamic range of detection spanning from 10 fg/mL to 1 ng/mL (0.01 ppt to 1 ppm). The selectivity of the device was tested using a competing pesticide; malathion and selectivity in detection was observed in the fg/mL regime in all the three cases. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of the herbicide atrazine on Ambystoma tigrinum metamorphosis: duration, larval growth, and hormonal response

USGS Publications Warehouse

Larson, Diane L.; McDonald, Susan; Hamilton, Steven J.; Fivizzani, Albert J.; Newton, Wesley E.

1998-01-01

We exposed larval tiger salamanders (Ambystoma tigrinum) reared in the laboratory from eggs collected from a prairie wetland in North Dakota to three concentrations of atrazine (0, 75, and 250 i??g/L) in a static renewal test to determine the pesticide's effect on (1) plasma corticosterone and thyroxine concentrations, (2) larval size, and (3) days-to-stage at stages 2 and 4 of metamorphic climax. We found significant effects of atrazine on each of these response variables. Plasma thyroxine was elevated in both atrazine-exposed groups compared to the control group; plasma corticosterone was depressed in the 75 i??g/L treatment compared with both the control and 250 i??g/L treatment. Larvae exposed to 75 i??g/L atrazine reached stage 4 later, but at a size and weight comparable to the control group. By contrast, larvae in the 250 i??g/L treatment progressed to stage 4 at the same time but at a smaller size and lower weight than larvae in the control group. These results indicate that the herbicide has the potential to influence tiger salamander life history. We present a model consistent with our results, whereby corticosterone and thyroxine interact to regulate metamorphosis of tiger salamanders based on nutrient assimilation and adult fitness

Toxicity of atrazine, glyphosate, and quinclorac in bullfrog tadpoles exposed to concentrations below legal limits.

PubMed

Dornelles, M F; Oliveira, G T

2016-01-01

This work sought to ascertain survival and possible changes in levels of glycogen, triglycerides, total lipids, cholesterol, protein, and lipid peroxidation in gills, liver, and muscle of bullfrog tadpoles (Lithobates catesbeianus) exposed to low concentrations of atrazine (2.5 μg L(-1)), glyphosate (18 μg L(-1)), and quinclorac (0.025 μg L(-1)) at laboratorial conditions. Tadpoles showed a reduction of glycogen and triglyceride in all organs and an increase in lipid peroxidation (LPO) compared with control animals. Total lipid in gills and muscle increased in exposure to atrazine, and gills alone in exposure to glyphosate, but decreased in gills, liver, and muscle after quinclorac. Cholesterol increased in gills and liver after atrazine, in gills and muscle after glyphosate, and decreased in liver after quinclorac. Total protein in gills decreased after exposure to all herbicides, increased in muscle after atrazine, and in liver and muscle after quinclorac. These findings show that at concentrations of these herbicides tested can lead to an increase in energy expenditure to maintain homeostasis and survival of these animals despite the increase in lipid peroxidation levels in all organs analyzed. Responses observed can be one of the factors responsible for the decline in the number of amphibians around the world.

Atrazine degradation and enzyme activities in an agricultural soil under two tillage systems.

PubMed

Mahía, Jorge; Martín, Angela; Carballas, Tarsy; Díaz-Raviña, Montserrat

2007-05-25

The content of atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) as well as the activities of two soil enzymes (urease and beta-glucosidase) were evaluated in an acid agricultural soil, located in a temperate humid zone (Galicia, NW Spain), with an annual ryegrass-maize rotation under conventional tillage (CT) and no tillage (NT). Samples were collected during two consecutive years from the arable layer at two depths (0-5 cm and 5-20 cm) and different times after atrazine application. Hydroxyatrazine and deisopropylatrazine were the main metabolites resulting from atrazine degradation in the acid soil studied, the highest levels being detected in the surface layer of the NT treatment. A residual effect of atrazine was observed since hydroxyatrazine was detected in the arable layer (0-5 cm, 5-20 cm) even one year after the herbicide application. Soil enzyme activities in the upper 5 cm layer under NT were consistently higher than those in the same layer under CT. Urease and beta-glucosidase activities decreased with depth in the profile under NT but they did not show any differences between the two depths for the plots under CT. For both tillage systems enzyme activities also reflected temporal changes during the maize cultivation; however, no consistent effect of the herbicide application was observed.

Effects of atrazine on fish, amphibians, and aquatic reptiles: a critical review.

PubMed

Solomon, Keith R; Carr, James A; Du Preez, Louis H; Giesy, John P; Kendall, Ronald J; Smith, Ernest E; Van Der Kraak, Glen J

2008-01-01

The herbicide atrazine is widely used in agriculture for the production of corn and other crops. Because of its physical and chemical properties, atrazine is found in small concentrations in surface waters--habitats for some species. A number of reports on the effects of atrazine on aquatic vertebrates, mostly amphibians, have been published, yet there is inconsistency in the effects reported, and inconsistency between studies in different laboratories. We have brought the results and conclusions of all of the relevant laboratory and field studies together in this critical review and assessed causality using procedures for the identification of causative agents of disease and ecoepidemiology derived from Koch's postulates and the Bradford-Hill guidelines. Based on a weight of evidence analysis of all of the data, the central theory that environmentally relevant concentrations of atrazine affect reproduction and/or reproductive development in fish, amphibians, and reptiles is not supported by the vast majority of observations. The same conclusions also hold for the supporting theories such as induction of aromatase, the enzyme that converts testosterone to estradiol. For other responses, such as immune function, stress endocrinology, parasitism, or population-level effects, there are no indications of effects or there is such a paucity of good data that definitive conclusions cannot be made.

Transparently Interposing User Code at the System Interface

DTIC Science & Technology

1992-09-01

trademarks of Symantec Corporation. AFS is a trademark of Transarc Corporation. PC-cillin is a trademark of Trend Micro Devices, Incorporated. Scribe is a...communication. Finally, both the Norton AntiVirus [Symantec 91b] and PC-cillin [ Trend 90] anti-virus applications intercept destructive file operations made... Trend Micro Devices, Incorporated, 1990. [Tygar & Yee 91] J. D. Tygar, Bennet Yee. Dyad: A System for Using Physically Secure Coprocessors

SORPTION OF VINCLOZOLIN AND ATRAZINE ON FOUR GEOSORBENTS

EPA Science Inventory

The objectives of this study were to evaluate the magnitude and kinetics of vinclozolin and atrazine sorption on one surface soil and three freshwater sediments using batch and column techniques. Data from miscible displacement column studies were analyzed using a two-domain, fir...

A SCREENING-LEVEL MODEL EVALUATION OF ATRAZINE IN THE LAKE MICHIGAN BASIN

EPA Science Inventory

Atrazine, a widely used herbicide in the agricultural regions of the Lake Michigan basin, was selected as a priority toxic chemical study in the United States Environmental Protection Agency (U.S. EPA) - sponsored Lake Michigan Mass Balance Project.

Veterinary antibiotic effects on atrazine degradation and soil microorganisms

USDA-ARS?s Scientific Manuscript database

Veterinary antibiotics (VAs) in manure applied to agricultural lands may change agrichemical degradation by altering soil microbial community structure or function. The objectives of this study were to investigate the influence of two VAs, sulfamethazine (SMZ) and oxytetracycline (OTC), on atrazine ...

Bioavailability of organoclay formulations of atrazine in soil

USDA-ARS?s Scientific Manuscript database

Pesticide formulations based on organoclays have been proposed to prolong the efficacy and reduce the environmental impact of pesticides in soil. This research addressed the question of whether organoclay-based formulations of atrazine are irreversibly sorbed or are bioavailable for bacterial degrad...

Atrazine affects kidney and adrenal hormones (AHs) related genes expressions of rare minnow (Gobiocypris rarus).

PubMed

Yang, Lihua; Zha, Jinmiao; Li, Wei; Li, Zhaoli; Wang, Zijian

2010-05-05

Atrazine, one of the most widely used herbicides, has been proved to interfere with sexual hormones. However few studies have considered the effects of atrazine on adrenal hormones (AH). In this study, rare minnow (Gobiocypris rarus) was exposed to 0, 3, 10, 33, 100 and 333microg/l atrazine for 28 days. The histopathology of kidney and gill was examined and the expressions of AHs-related genes including Na(+),K(+)-ATPase, glucocorticoid receptor (gr), heat shock protein 70 (hsp70), and heat shock protein 90 (hsp90) in kidney and gill were quantitatively determined. Histopathological observation revealed obvious lesions in gill including hyperplasia, necrosis in epithelium region, aneurysm and lamellar fusion at concentrations as low as 10microg/l. The observed lesions in kidney included extensive expansion in the lumen, degenerative and necrotic changes of the tubular epithelia, shrinkage of the glomerulus as well as increase of the Bowman's space at concentrations as low as 10microg/l. The expressions of Na(+),K(+)-ATPase, gr, hsp70 and hsp90 in the kidney of females were significantly decreased at all concentrations. For males, the expressions of hsp90 in the kidney of all treated groups were significantly down-regulated, while gr at all concentrations and hsp70 at 10, 33, 100microg/l were significantly up-regulated. However in the gill, the expressions of these genes were not significantly different from the control. These results indicated that exposure to atrazine caused impairments of kidney and gill of fish at environmental related concentrations. Histopathological lesions could partly attribute to the changes of the expressions of AHs-related genes in kidney. We concluded also that atrazine is a potential AHs-disruptor and AHs-related genes in kidney of fish could be used as sensitive molecular biomarkers.

Sorbed atrazine shifts into non-desorbable sites of soil organic matter during aging.

PubMed

Park, Jeong-Hun; Feng, Yucheng; Cho, Sung Yong; Voice, Thomas C; Boyd, Stephen A

2004-11-01

Soil-chemical contact time (aging) is an important determinant of the sorption and desorption characteristics of the organic contaminants and pesticides in the environment. The effects of aging on mechanism-specific sorption and desorption of atrazine were studied in soil and clay slurries. Sorption isotherm and desorption kinetic experiments were performed, and soil-water distribution coefficients and desorption rate parameters were evaluated using linear and non-linear sorption equations and a three-site desorption model, respectively. Aging time for sorption of atrazine in sterilized soil and clay slurries ranged from 2 days to 8 months. Atrazine sorption isotherms were nearly linear (r(2)>0.97) and sorption coefficients were strongly correlated to soil organic carbon content. Sorption distribution coefficients (K(d)) increased with increase in age in all five soils studied, but not for K-montmorillonite. Sorption non-linearity did not increase with increase in age except for the Houghton muck soil. Desorption profiles were well described by the three-site desorption model. The equilibrium site fraction (f(eq)) decreased and the non-desorbable site fraction (f(nd)) increased as a function of aging time in all soils. For K-montmorillonite, f(nd) approximately 0 regardless of aging, showing that aging phenomena are sorbent/mechanism specific. In all soils, it was found that when normalized to soil organic matter content, the concentration of atrazine in desorbable sites was relatively constant, whereas that in non-desorbable site increased. This, and the lack of aging effects on desorption from montmorillonite, suggests that sorption into non-desorbable sites of soil organic matter is primary source of increased atrazine sorption in soils during aging.

Individual and mixture effects of five agricultural pesticides on zebrafish (Danio rerio) larvae.

PubMed

Wang, Yanhua; Yang, Guiling; Dai, Dejiang; Xu, Zhenlan; Cai, Leiming; Wang, Qiang; Yu, Yijun

2017-02-01

In the present study, we evaluated the individual and mixture toxicities of imidacloprid and other four pesticides (atrazine, chlorpyrifos, butachlor, and λ-cyhalothrin) to the zebrafish (Danio rerio) larvae in order to clarify the interactive effects of pesticides on aquatic organisms. Results from the 96-h semi-static toxicity test indicated that chlorpyrifos, λ-cyhalothrin, and butachlor had the highest toxicities to D. rerio with an LC 50 value ranging from 0.28 (0.13∼0.38) to 0.45 (0.31∼0.59) mg AI L -1 , followed by atrazine with an LC 50 value of 15.63 (10.71∼25.76) mg AI L -1 , while imidacloprid exhibited the least toxicity to the organisms with an LC 50 value of 143.7 (99.98∼221.6) mg AI L -1 . Seven pesticide mixtures (two binary mixtures of imidacloprid + atrazine and imidacloprid + λ-cyhalothrin, two ternary mixtures of imidacloprid + atrazine + λ-cyhalothrin and imidacloprid + butachlor + λ-cyhalothrin, two quaternary mixtures of imidacloprid + atrazine + chlorpyrifos + λ-cyhalothrin and imidacloprid + chlorpyrifos + butachlor + λ-cyhalothrin, and one quinquenary mixture of imidacloprid + atrazine + chlorpyrifos + butachlor + λ-cyhalothrin) exhibited synergistic effects with equitoxic ratio and equivalent concentration on the zebrafish. Our results highlighted that the simultaneous presence of several pesticides in the aquatic environment might lead to increased toxicity, causing serious damage to the aquatic ecosystems compared with their individual toxicities. Therefore, the toxic effects of both individual pesticides and their mixtures should be incorporated into the environmental risk evaluation of pesticides.

Developmental origins of neurotransmitter and transcriptome alterations in adult female zebrafish exposed to atrazine during embryogenesis.

PubMed

Wirbisky, Sara E; Weber, Gregory J; Sepúlveda, Maria S; Xiao, Changhe; Cannon, Jason R; Freeman, Jennifer L

2015-07-03

Atrazine is an herbicide applied to agricultural crops and is indicated to be an endocrine disruptor. Atrazine is frequently found to contaminate potable water supplies above the maximum contaminant level of 3μg/L as defined by the U.S. Environmental Protection Agency. The developmental origin of adult disease hypothesis suggests that toxicant exposure during development can increase the risk of certain diseases during adulthood. However, the molecular mechanisms underlying disease progression are still unknown. In this study, zebrafish embryos were exposed to 0, 0.3, 3, or 30μg/L atrazine throughout embryogenesis. Larvae were then allowed to mature under normal laboratory conditions with no further chemical treatment until 7 days post fertilization (dpf) or adulthood and neurotransmitter analysis completed. No significant alterations in neurotransmitter levels was observed at 7dpf or in adult males, but a significant decrease in 5-hydroxyindoleacetic acid (5-HIAA) and serotonin turnover was seen in adult female brain tissue. Transcriptomic analysis was completed on adult female brain tissue to identify molecular pathways underlying the observed neurological alterations. Altered expression of 1928, 89, and 435 genes in the females exposed to 0.3, 3, or 30μg/L atrazine during embryogenesis were identified, respectively. There was a high level of overlap between the biological processes and molecular pathways in which the altered genes were associated. Moreover, a subset of genes was down regulated throughout the serotonergic pathway. These results provide support of the developmental origins of neurological alterations observed in adult female zebrafish exposed to atrazine during embryogenesis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Interactions of an insecticide, herbicide, and natural stressors in amphibian community mesocosms

USGS Publications Warehouse

Boone, M.D.; James, S.M.

2003-01-01

Amphibians developing in wetlands embedded within or near agricultural lands may frequently encounter chemical mixtures. The objectives of our study were to determine the effects that post-application concentrations of an insecticide (carbaryl) and an herbicide (atrazine) have on body mass, development, and survival of two anuran species (southern leopard frog, Rana sphenocephala; American toad, Bufo americanus) and two caudate species (spotted salamander, Ambystoma maculatum; small-mouthed salamander, A. texanum) reared in outdoor cattle tank mesocosms. In one experiment, we manipulated tadpole density (low or high), carbaryl exposure (0, 3.5, 7.0 mg/L), and atrazine exposure (0 or 200 μg/L) to test for effects on development, mass, and survival of larvae. In a second experiment, we manipulated pond hydroperiod (constant or drying), carbaryl exposure (0 or 5 mg/L), and atrazine exposure (0 or 200 μg/L) to test for effects on mass, time, and survival to metamorphosis. Salamanders were virtually eliminated in carbaryl treatments, indicating that at realistic levels, this insecticide could cause population declines for salamanders in contaminated habitats. Carbaryl also had negative effects on toad survival. Exposure to atrazine had negative effects on body size, development, and time to metamorphosis in anuran species, which were associated with reduced chlorophyll levels. Both chemicals interacted significantly with density or hydroperiod, indicating that the environmental conditions could influence the impact of a contaminant. A significant atrazine-by-carbaryl interaction resulted in smaller and less developed spotted salamander larvae than in control ponds. Atrazine exposure, however, appeared to moderate negative effects of carbaryl for spotted salamanders. Our research suggests that important changes in the community's food web result from chemical exposure, which influence the susceptibility of amphibian species to contaminants.

Immunomodulatory effects of maternal atrazine exposure on male Balb/c mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Alexander M.; Brundage, Kathleen M.; Schafer, Rosana

2006-07-01

Atrazine is a widely used herbicide applied to corn, sugar and other crops as a broad leaf weed inhibitor. Using the Balb/c mouse model, we have determined that prenatal/lactational exposure to atrazine alters adult immune function. Pregnant Balb/c dams were exposed subcutaneously for 21 days via time release pellets to 700 {mu}g per day of atrazine beginning between days 10 and 12 of pregnancy. Prenatal/Lactational exposure caused no overt physical malformations in the offspring and had no effect on the number of litters carried to term or the litter size. Upon reaching early adulthood (approximately 3 months of age), themore » state of their immune system was evaluated. There were no changes in body weight or in the organ to body weight ratio of the spleen. Additionally, no changes were observed in the number of CD8{sup +} T cell, CD4{sup +} T cell, or B220{sup +} B cell subpopulations in the spleen. T cell function was assessed by measuring proliferation and cytolytic activity after in vitro allogeneic stimulation. Male mice which had been prenatally/lactationally exposed to atrazine had an increase in both T cell proliferation and cytolytic activity. The humoral immune response was assessed after immunization with heat killed Streptococcus pneumoniae (HKSP). There was a significant increase in the number of HKSP-specific IgM secreting B cells in the spleen of prenatal/lactational exposed male mice. Inasmuch as atrazine is a widespread environmental contaminant, this immunopotentiation raises concerns that it may potentiate clinical diseases, such as autoimmune disease and hypersensitivity, and needs to be carefully monitored and studied.« less

Aqueous-phase disappearance of atrazine, metolachlor, and chlorpyrifos in laboratory aquaria and outdoor macrocosms

USGS Publications Warehouse

Mazanti, L.; Rice, C.; Bialek, K.; Sparling, D.; Stevenson, C.; Johnson, W.E.; Kangas, P.; Rheinstein, J.

2003-01-01

Dissipation processes are described for a combination of commonly used pesticides--atrazine (6-chloro-4--ethylamino-6-isopropylamino-s-triazine), metolachlor (2-chloro-N-[2-ethyl-6-methyl-phenyl]-N-[2-methoxy-l-methylethyl] acetamide), and chlorpyrifos (O-O diethyl O-[3,5,6-trichloro-2-pyridinyl] phosphorothioate)--in a laboratory and outdoor pond systems. Dosing rates and timing were designed to duplicate those common in the mid-Atlantic Coastal Plain, USA. Treatment ranged from 2 and 2.5 mg/L to 0.2 and 0.25 mg/L respectively for atrazine and metolachlor, and chlorpyrifos was added at 1.0 and 0.1 mg/L in the aquaria and at 0.1 mg/L in the outdoor macrocosms. Chlorpyrifos disappearance was rapid in all of the systems and followed a two-phase sequence. Initial half-lives varied from 0.16 da), to 0.38 day and showed similar rates in the aquaria and the outdoor systems. The second phase of the chlorpyrifos loss pattern was slower (18-20 days) in all the treatments except for the low herbicide treatment in the outdoor test, where it was 3.4 days. Compared to the outdoor system, herbicide losses were much slower in the aquaria, e.g., 150 days for atrazine and 55 days for metolachlor, and no appreciable loss of herbicide was apparent in the high-treated aquaria. In the outdoor systems, the half-lives for the low herbicide treatment were 27 days and 12 days, respectively, for atrazine and metolachlor, and 48 and 20 days, respectively for the high herbicide-treated pond. Very low levels of CIAT (6-amino-2-chloro-4-iso-propylamino-s-triazine) and CEAT (2-chloro-4-ethylamino-6-ethylamino-s-triazine), degradation products of atrazine, were observed in the outdoor studies.

Characterization of spectral responses of dissolved organic matter (DOM) for atrazine binding during the sorption process onto black soil.

PubMed

Wang, Yifan; Zhang, Xinyuan; Zhang, Xing; Meng, Qingjuan; Gao, Fengjie; Zhang, Ying

2017-08-01

This study was aim to investigate the interaction between soil-derived dissolved organic matter (DOM) and atrazine as a kind of pesticides during the sorption process onto black soil. According to the experimental data, the adsorption capacity of Soil + DOM, Soil and DOM were 41.80, 31.45 and 9.35 mg kg -1 , separately, which indicated that DOM significantly enhanced the adsorption efficiency of atrazine by soil. Data implied that the pseudo-second-order kinetic equation could well explain the adsorption process. The adsorption isotherms (R 2  > 0.99) had a satisfactory fit in both Langmuir and Freundlich models. Three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence, two-dimensional correlation spectroscopy (2D-COS) and Fourier transform infrared spectroscopy (FT-IR) were selected to analyze the interaction between DOM and atrazine. 3D-EEM showed that humic acid-like substances were the main component of DOM. The fluorescence of DOM samples were gradually quenched with the increased of atrazine concentrations. Synchronous fluorescence spectra showed that static fluorescence quenching was the main quenching process. 2D-COS indicated that the order of the spectral changes were as following: 336 nm > 282 nm. Furthermore, the fluorescence quenching of humic-like fraction occurred earlier than that of protein-like fraction under atrazine surroundings. FT-IR spectra indicated that main compositions of soil DOM include proteins, polysaccharides and humic substances. The findings of this study are significant to reveal DOM played an important role in the environmental fate of pesticides during sorption process onto black soil and also provide more useful information for understanding the interaction between DOM and pesticides by using spectral responses. Copyright © 2017. Published by Elsevier Ltd.

CelF of Orpinomyces PC-2 has an intron and encodes a cellulase (CelF) containing a carbohydrate-binding module.

PubMed

Chen, Huizhong; Li, Xin-Liang; Blum, David L; Ximenes, Eduardo A; Ljungdahl, Lars G

2003-01-01

A cDNA, designated celF, encoding a cellulase (CelF) was isolated from the anaerobic fungus Orpinomyces PC-2. The open reading frame contains regions coding for a signal peptide, a carbohydrate-binding module (CBM), a linker, and a catalytic domain. The catalytic domain was homologous to those of CelA and CelC of the same fungus and to that of the Neocallimastix patriciarum CELA, but CelF lacks a docking domain, characteristic for enzymes of cellulosomes. It was also homologous to the cellobiohydrolase IIs and endoglucanases of aerobic organisms. The gene has a 111-bp intron, located within the CBM-coding region. Some biochemical properties of the purified recombinant enzyme are described.

Enhanced s-triazine Degradation and Sugar Cane Weed Control Options

USDA-ARS?s Scientific Manuscript database

Soil borne bacteria on all continents except Antarctica have developed the ability to rapidly degrade the herbicide atrazine. Reduced residual weed control with atrazine in soils exhibiting enhanced degradation was confirmed under Mississippi Delta corn production and is expected to be occurring in...

77 FR 30526 - Product Cancellation Order for Certain Pesticide Registrations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-23

... Chemical name 000264-00438 Bronate Herbicide... MCPA,2-ethylhexyl ester. Bromoxynil octanoate. 000264-00477 Buctril + Atrazine Bromoxynil octanoate Herbicide. Atrazine. 000264-00586 Sedagri Batril 20W Bromoxynil Herbicide. octanoate. 000264-00650 Silverado Herbicide. Fenoxaprop-p-ethyl. 000264-00699 Rhino Brand MCPA,2...

Potiential role of the adrenal axis on the reproductive effects of Atrazine

EPA Science Inventory

We and others reported that atrazine (ATR) disrupts the regulation of the ovulatory luteinizing hormone (LH) surge and the hormonal control of other reproductive functions in the rat. In addition, administration of ATR or the intermediate metabolite deisopropylatrazine (DIA) stim...

INFILTRATION OF ATRAZINE AND METABOLOTES FROM A STREAM TO AN ALLUVIAL AQUIFER

EPA Science Inventory

The infiltration of atrazine, deethylatrazine, and deisopropylatrazine from Walnut Creek, a tributary stream, to the alluvial valley aquifer along the South Skunk River in central Iowa occurred where the stream transects the river's flood plain. A preliminary estimate indicated t...

ATRAZINE DISRUPTS THE HYPOTHALAMIC CONTROL OF PITUITARY-OVARIAN FUNCTION

EPA Science Inventory

The chloro-S-triazine herbicides (i.e., atrazine, simazine, cyanazine) constitute the largest group of herbicides sold in the United States. Despite their extensive usage, relatively little is known about the possible human-health effects and mechanism(s) of action of these compo...

EFFECT OF SIMAZINE ON MALE REPRODUCTIVE DEVELOPMENT IN THE RAT

EPA Science Inventory

The chlorotriazine herbicides, such as atrazine, are used extensively in the United States each year. Chlorotriazine metabolites, as well as the parent compounds, have been detected in surface and ground water in areas of major usage. Previously, we found that atrazine delayed ...

Movement and fate of atrazine and bromide in central Kansas croplands

USGS Publications Warehouse

Sophocleous, M.; Townsend, M.A.; Whittemore, Donald O.

1990-01-01

Two flooding experiments were conducted at two sites with different soils to study the transport and fate of the commonly used herbicide atrazine and inorganic chemicals in the Great Bend Prairie croplands of south-central Kansas. The instantaneous profile method supplemented by the use of an organic (atrazine) and an inorganic (bromide) tracer chemical was used to characterize in situ the hydraulic and chemical properties of the appropriately instrumented field sites. Atrazine readily degraded to hydroxyatrazine and biodegradation by-products and was not detected deeper in the soil profile and underlying shallow aquifer. The classical processes of chemical movement based on porous media-equilibrium-diffuse flow did not fit the data well at either site. Incompletely mixed, slug flow appeared to predominate at one of the sites and preferential flow at the other. The slug movement caused 'piston-type' displacement of more saline solutions in the soil profile to the shallow water table. Recommendations for conducting related field studies based on our sampling experience are given. ?? 1990.

Binding characteristics of anti-atrazine monoclonal antibodies and their fragments synthesised in bacteria and plants.

PubMed

Strachan, G; Grant, S D; Learmonth, D; Longstaff, M; Porter, A J; Harris, W J

1998-09-15

Single-chain antibody fragments (scAb), specific for the herbicide atrazine, have been expressed in the bacterium Escherichia coli and in transgenic tobacco plants. The scAb could be purified as a monomer (monovalent) via a hexa-histidine tail or as a dimer (divalent) by antibody affinity chromatography. In competition ELISA, the bacterial scAb showed the same specificity for atrazine and related triazine herbicides as the parental mAb cell line, but both plant and bacterial monomeric scAbs showed increased sensitivity to free atrazine. Surface plasmon resonance (BIAcore 2000) analysis confirmed that purified scAb, derived from plant or bacteria, retained similar association rates as the mAb. However, the monomeric plant and bacterial scAbs showed a lower affinity for immobilised antigen, than the equivalent dimeric scAbs or mAb. This decrease in affinity was due to a 10 fold slower dissociation rate and is likely due to loss of the avidity contribution of dimeric molecules.

Atrazine and Nitrate in Public Drinking Water Supplies and Non-Hodgkin Lymphoma in Nebraska, USA

PubMed Central

Rhoades, Martha G.; Meza, Jane L.; Beseler, Cheryl L.; Shea, Patrick J.; Kahle, Andy; Vose, Julie M.; Eskridge, Kent M.; Spalding, Roy F.

2013-01-01

A secondary analysis of 1999–2002 Nebraska case-control data was conducted to assess the risk of non-Hodgkin lymphoma (NHL) associated with exposure to nitrate- and atrazine-contaminated drinking water. Water chemistry data were collected and weighted by well contribution and proximity of residence to water supply, followed by logistic regression to determine odds ratios (OR) and 95% confidence intervals (CI). We found no association between NHL risk and exposure to drinking water containing atrazine or nitrate alone. Risk associated with the interaction of nitrate and atrazine in drinking water was elevated (OR, 2.5; CI, 1.0–6.2). Risk of indolent B-cell lymphoma was higher than risk of aggressive B-cell lymphoma (indolent: OR, 3.5; CI, 1.0–11.6 vs. aggressive: OR, 1.9; CI, 0.6–5.58). This increased risk may be due to in vivo formation and subsequent metabolism of N-nitrosoatrazine. A larger study is warranted to confirm our findings. PMID:23515852

Characterization of biochars derived from agriculture wastes and their adsorptive removal of atrazine from aqueous solution: A comparative study.

PubMed

Liu, Na; Charrua, Alberto Bento; Weng, Chih-Huang; Yuan, Xiaoling; Ding, Feng

2015-12-01

The physicochemical properties of biochars produced from soybeans (SBB), corn stalks (CSB), rice stalks (RSB), poultry manure (PMB), cattle manure (CMB), and pig manure (PgMB) and their adsorption characteristics of atrazine were investigated. The adsorption capacity increased with the increase of temperature and initial atrazine concentration. More atrazine was removed from basic solutions than acidic solutions, due to the effects of adsorption and hydrolysis. The Freundlich isotherm adsorption parameters indicated that the adsorption capacity decreased in the order SBB>RSB>CMB>CSB>PMB>PgMB, which is associated to the pore volume of biochars. The total pore volume and biochar pH were concluded to play important roles in determining the adsorption capacity, and they may have contributed to physical adsorption mechanisms dominating the overall adsorption process (the low activation energy for all of the biochars). Modified Freundlich and intraparticle diffusion models were used to describe the kinetics of the adsorption process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rapid detection of atrazine and metolachlor in farm soils: gas chromatography-mass spectrometry-based analysis using the bubble-in-drop single drop microextraction enrichment method.

PubMed

Williams, D Bradley G; George, Mosotho J; Marjanovic, Ljiljana

2014-08-06

Tracking of metolachlor and atrazine herbicides in agricultural soils, from spraying through to harvest, was conducted using our recently reported "bubble-in-drop single-drop microextraction" method. The method showed good linearity (R(2) = 0.999 and 0.999) in the concentration range of 0.01-1.0 ng/mL with LOD values of 0.01 and 0.02 ng/mL for atrazine and metolachlor, respectively. Sonication methods were poor at releasing these herbicides from the soil matrixes, while hot water extraction readily liberated them, providing an efficient accessible alternative to sonication techniques. Good recoveries of 97% and 105% were shown for atrazine and metolachlor, respectively, from the soil. The spiking protocol was also investigated, resulting in a traceless spiking method. We demonstrate a very sensitive technique by which to assess, for example, the length of residence of pesticides in given soils and thus risk of exposure.

Combining supercritical fluid extraction of soil herbicides with enzyme immunoassay analysis.

PubMed

Stearman, G K

2001-10-01

Supercritical fluid extraction (SFE) of soil herbicides followed by enzyme immunoassay analysis (EIA) is explained in a step-by-step process. Extracted herbicides, include 2,4-D, simazine, atrazine, and alachlor. The herbicide, trifluralin was not successfully analyzed by EIA because of crossreacting metabolites. Problems with SFE, including uneven packing of cells, leaks, uneven flow and clogging, can largely be eliminated as the method parameters are optimized. It was necessary to add modifiers including methanol or acetone to the SF CO2 to increase the solubility of the analytes. Detection limits of 2.5 ng/g soil for atrazine and alachlor and 15 ng/g soil for simazine and 2,4-D without concentration of the sample were achieved. Recoveries above 80% and relative standard deviations (RSDs) less than 15% for 2,4-D simazine, atrazine and alachlor were achieved. Atrazine and alachlor recoveries were above 90% with RSDs below 10%. Forty soil samples could be extracted and analyzed in an 8-h day.

Effects of carbon amendment on in situ atrazine degradation and total microbial biomass.

PubMed

Ngigi, Anastasiah N; Getenga, Zachary M; Dörfler, Ulrike; Boga, Hamadi I; Kuria, Benson; Ndalut, Paul; Schroll, Reiner

2013-01-01

This study elucidates the effects of carbon amendment on metabolic degradation of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) and total microbial biomass in soil. Degradation of (14)C-ring-labelled atrazine was monitored in laboratory incubations of soils supplemented with 0, 10, 100 and 1000 μg g(-1) sucrose concentrations. An experiment to determine the effect of carbon amendment on total microbial biomass and soil respiration was carried out with different concentrations of sucrose and non-labelled atrazine. The soils were incubated at a constant temperature and constant soil moisture at water potential of -15 kPa and a soil density of 1.3 g cm(-3). Mineralization of (14)C-ring-labelled atrazine was monitored continuously over a period of 59 d in the first experiment. The CO(2) production was monitored for 62 d in the second experiment and microbial biomass determined at the end of the incubation period. The addition of 1000 μg g(-1) sucrose reduced atrazine mineralization to 43.5% compared to 51.7% of the applied amount for the treatment without sucrose. The addition of 1000 μg g(-1) sucrose modified the transformation products to 1.08 μg g(-1) deisopropylatrazine (DIA), 0.32 μg g(-1) desethylatrazine (DEA) and 0.18 μg g(-1) deisopropyl-2-hydroxyatrazine (OH-DIA). Treatment without sucrose resulted in formation of 0.64 μg g(-1) hydroxyatrazine (HA), 0.28 μg g(-1) DIA and 0.20 μg g(-1) OH-DIA. Atrazine dealkylation was enhanced in treatments with 100 and 1000 μg g(-1) of sucrose added. HA metabolite was formed in the control (no sucrose) and in the presence of 10 μg g(-1) of sucrose, whereas DEA was only detected in treatment with 1000 μg g(-1) sucrose. Results indicate that total microbial biomass increased significantly (P < 0.001) with the addition of 1000 μg g(-1) sucrose.

Processes controlling the episodic streamwater transport of atrazine and other agrichemicals in an agricultural watershed

USGS Publications Warehouse

Hyer, Kenneth; Hornberger, George M.; Herman, Janet S.

2001-01-01

Episodic streamwater transport of atrazine (a common agricultural herbicide) and nutrients has been observed throughout agricultural watersheds in the United States and poses a serious threat to the quality of its water resources. Catchment-scale atrazine and nutrient transport processes after agricultural application are still poorly understood, and predicting episodic streamwater composition remains an elusive goal. We instrumented a 1.2-km2 agricultural catchment near Harrisonburg, Virginia, and examined streamwater, overland flow, soil water, groundwater, and rainfall during the summer of 1998. Storm chemographs demonstrated different patterns for constituents derived primarily from weathering (silica and calcium), compared to constituents derived primarily from early spring land applications (nitrate, atrazine, DOC, potassium, chloride, and sulfate). During storms, the concentrations of silica and calcium decreased, the atrazine response was variable, and the concentrations of nitrate, DOC, potassium, chloride, and sulfate increased; the elevated nitrate signal lagged several hours behind the other elevated constituents. Graphical and statistical analyses indicated a relatively stable spring-fed baseflow was modified by a mixture of overland flow and soil water. A rapid, short-duration overland-flow pulse dominated the streamflow early in the event and contributed most of the potassium, DOC, chloride, suspended sediment, and atrazine. A longer-duration soil–water pulse dominated the streamflow later in the event and contributed the nitrate as well as additional potassium, DOC, sulfate, and atrazine. The contributions to the episodic streamflow were quantified using a flushing model in which overland-flow and soil–water concentrations decreased exponentially with time during an episode. Flushing time constants for the overland-flow and soil–water reservoirs were calculated on a storm-by-storm basis using separate tracers for each time-variable reservoir. Initial component concentrations were estimated through regression analyses. Mass-balance calculations were used for flow separations and to predict the observed streamwater composition. Model forecasts indicated that reduced fertilizer and pesticide application (rather than elimination of overland-flow or soil–water contributions) was necessary to improve the episodic streamwater composition. This study provides important additional understanding of the catchment-scale processes by which land-applied pesticides and nutrients can move through agricultural systems.

Novel molecular events associated with altered steroidogenesis induced by exposure to atrazine in the intact and castrate male rat

EPA Science Inventory

Toxicology is increasingly focused on molecular events comprising adverse outcome pathways. Atrazine activates the hypothalamic-pituitary adrenal axis, but relationships to gonadal alterations are unknown. We characterized hormone profiles and adrenal (intact and castrate) and te...

DEVELOPMENTAL ATRAZINE EXPOSURE SUPPRESSES IMMUNE FUNCTION IN MALE, BUT NOT FEMALE SPRAGUE-DAWLEY RATS

EPA Science Inventory

Developmental Atrazine Exposure Suppresses Immune Function in Male, but not Female Sprague-Dawley Rats

Andrew A. Rooney,*,1 Raymond A. Matulka,? and Robert Luebke?

*College of Veterinary Medicine, Anatomy, Physiological Sciences and Radiology, NCSU, Raleigh, North...

ATRAZINE STIMULATES THE RELEASE OF ACTH AND ADRENAL STEROIDS IN MALE WISTAR RATS

EPA Science Inventory

Previously, we reported that atrazine (ATR) alters steroidogenesis in male Wistar rats resulting in increased serum corticosterone (C), progesterone (P), androgens and estrogens. The observation of increased C following single or multiple doses of ATR (up to 21 days of dosing) su...

Results of the Lake Michigan Mass Balance Project: Atrazine Modeling Report

EPA Science Inventory

This report covers an overview of chemical properties, measurements in air and water, model construct and assumptions, and results of mathematical mass balance modeling of the herbicide atrazine in the Lake Michigan basin. Within the context of the mass balance, an overview of a...

Interpretation of the Ecological Significance of Atrazine Stream-Water Concentrations Using a Statistically-Designed Monitoring Program

EPA Science Inventory

A risk assessment was conducted by the US Environmental Protection Agency (EPA) as part of the 2003 Interim Registration Eligibility Document (IRED) on atrazine. The assessment indicated potential community- and population-level risk to sensitive aquatic ecosystems at prolonged ...

Sugarcane Soils Exhibit Enhanced Atrazine Degradation And Cross Adaptation To Other Triazines

USDA-ARS?s Scientific Manuscript database

Reports of reduced residual weed control with atrazine in Florida and Hawaii soils indicate that enhanced triazine degradation may be occurring across the entire United States sugarcane production region. A previously developed triazine degradation assay was used to determine if Florida and Hawaii ...

Postplanting sprays of dalapon and atrazine to aid conifer establishment.

Treesearch

Edward J. Dimock; Ernest B. Collard

1981-01-01

A mixture of dalapon and atrazine consistently controlled grasses of forbs better than either herbicide used alone. Sprayed over and around newly planted ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), the mixture doubled tree survival...

EFFECT OF ATRAZINE ON IMPLANTATION AND EARLY PREGNANCY IN FOUR STRAINS OF RATS

EPA Science Inventory

Atrazine (ATR) is an herbicide that has been shown to have adverse reproductive effects including alterations in levels of pituitary hormones such as prolactin (prl) and luteinizing hormone (LH). Since prl's action to promote progesterone secretion is essential for the initiatio...

Introduction of biological agents into vegetative buffer to enhance rhizodegradation of atrazine

USDA-ARS?s Scientific Manuscript database

Introducing atrazine (ATR) degraders into riparian vegetative buffer strips (VBS) can be a promising bioremediation approach to accelerate the degradation of ATR and its degradation products deposited into VBS by surface runoff. A growth chamber study was conducted to investigated the synergistic ef...

GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winn, W.G.

The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

Impacts of Extraction Methods in the Rapid Determination of Atrazine Residues in Foods using Supercritical Fluid Chromatography and Enzyme-Linked Immunosorbent Assay: Microwave Solvent vs. Supercritical Fluid Extractions

PubMed Central

El-Saeid, Mohamed H.; Kanu, Ijeoma; Anyanwu, Ebere C.; Saleh, Mahmoud A.

2005-01-01

It is an accepted fact that many food products that we eat today have the possibility of being contaminated by various chemicals used from planting to processing. These chemicals have been shown to cause illnesses for which some concerned government agencies have instituted regulatory mechanisms to minimize the risks and the effects on humans. It is for these concerns that reliable and accurate rapid determination techniques are needed to effect proper regulatory standards for the protection of people's nutritional health. This paper, therefore, reports the comparative evaluation of the extraction methods in the determination of atrazine (commonly used in agricultural as a herbicide) residues in foods using supercritical fluid chromatography (SFC) and enzyme-linked immunosorbent assay (ELISA) techniques. Supercritical fluid extraction (SFE) and microwave solvent extraction (MSE) methods were used to test samples of frozen vegetables, fruit juice, and jam from local food markets in Houston. Results showed a high recovery percentage of atrazine residues using supercritical fluid coupled with ELISA and SFC than with MSE. Comparatively, however, atrazine was detected 90.9 and 54.5% using SFC and ELISA techniques, respectively. ELISA technique was, however, less time consuming, lower in cost, and more sensitive with low detection limit of atrazine residues than SFC technique. PMID:15674445

Effect of scale on the behavior of atrazine in surface waters

USGS Publications Warehouse

Capel, P.D.; Larson, S.J.

2001-01-01

Field runoff is an important transport mechanism by which agricultural pesticides, including atrazine, move into the hydrologic environment. Atrazine is chosen because it is widely used, is transported in runoff relatively easily, is widely observed in surface waters, and has relatively little loss in the stream network. Data on runoff of atrazine from experimental plot and field studies is combined with annual estimates of load in numerous streams and rivers, resulting in a data set with 408 observations that span 14 orders of magnitude in area. The load as a percent of use (LAPU) on an annual basis is the parameter that is compared among the studies. There is no difference in the mean or range of LAPU values for areas from the size of experimental field plots (???0.000023 ha) and small watersheds (<100 000 ha). The relatively invariant LAPU value observed across a large range of watershed areas implies that the characteristics of atrazine itself (application method and chemical properties) are important in determining the extent of runoff. The variable influences on the extent of runoff from individual watershed characteristics and weather events are superimposed on the relatively invariant LAPU value observed across the range of watershed areas. The results from this study establish the direct relevance for agricultural field plot studies to watershed studies across the full range of scale.

Decomposition of atrazine traces in water by combination of non-thermal electrical discharge and adsorption on nanofiber membrane.

PubMed

Vanraes, Patrick; Willems, Gert; Daels, Nele; Van Hulle, Stijn W H; De Clerck, Karen; Surmont, Pieter; Lynen, Frederic; Vandamme, Jeroen; Van Durme, Jim; Nikiforov, Anton; Leys, Christophe

2015-04-01

In recent decades, several types of persistent substances are detected in the aquatic environment at very low concentrations. Unfortunately, conventional water treatment processes are not able to remove these micropollutants. As such, advanced treatment methods are required to meet both current and anticipated maximally allowed concentrations. Plasma discharge in contact with water is a promising new technology, since it produces a wide spectrum of oxidizing species. In this study, a new type of reactor is tested, in which decomposition by atmospheric pulsed direct barrier discharge (pDBD) plasma is combined with micropollutant adsorption on a nanofiber polyamide membrane. Atrazine is chosen as model micropollutant with an initial concentration of 30 μg/L. While the H2O2 and O3 production in the reactor is not influenced by the presence of the membrane, there is a significant increase in atrazine decomposition when the membrane is added. With membrane, 85% atrazine removal can be obtained in comparison to only 61% removal without membrane, at the same experimental parameters. The by-products of atrazine decomposition identified by HPLC-MS are deethylatrazine and ammelide. Formation of these by-products is more pronounced when the membrane is added. These results indicate the synergetic effect of plasma discharge and pollutant adsorption, which is attractive for future applications of water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

VeryVote: A Voter Verifiable Code Voting System

NASA Astrophysics Data System (ADS)

Joaquim, Rui; Ribeiro, Carlos; Ferreira, Paulo

Code voting is a technique used to address the secure platform problem of remote voting. A code voting system consists in secretly sending, e.g. by mail, code sheets to voters that map their choices to entry codes in their ballot. While voting, the voter uses the code sheet to know what code to enter in order to vote for a particular candidate. In effect, the voter does the vote encryption and, since no malicious software on the PC has access to the code sheet it is not able to change the voter’s intention. However, without compromising the voter’s privacy, the vote codes are not enough to prove that the vote is recorded and counted as cast by the election server.

Error threshold for color codes and random three-body Ising models.

PubMed

Katzgraber, Helmut G; Bombin, H; Martin-Delgado, M A

2009-08-28

We study the error threshold of color codes, a class of topological quantum codes that allow a direct implementation of quantum Clifford gates suitable for entanglement distillation, teleportation, and fault-tolerant quantum computation. We map the error-correction process onto a statistical mechanical random three-body Ising model and study its phase diagram via Monte Carlo simulations. The obtained error threshold of p(c) = 0.109(2) is very close to that of Kitaev's toric code, showing that enhanced computational capabilities do not necessarily imply lower resistance to noise.

Atrazine Does Not Induce Pica Behavior at Doses that Increase Hypothalamic-Pituitary-Adrenal Axis Activation and Cause Conditioned Taste Avoidance.

EPA Science Inventory

Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH), serum corticosterone (CORT) and progesterone. The mechanism for these effects is unknown. To tes...

Proposed Methodology for Specifying Atrazine Levels of Concern for Protection of Plant Communities in Freshwater Ecosystems

EPA Science Inventory

This document describes a proposed methodology for setting levels of concern (LOCs) for atrazine in natural freshwater systems to prevent unacceptably adverse effects on the aquatic plant communities in those systems. LOCs regarding effects on humans and possible effects on amph...

REGIONAL MODELING OF THE ATMOSPHERIC TRANSPORT AND DEPOSITION OF ATRAZINE

EPA Science Inventory

A version of the Community Multiscale Air Quality (CMAQ) model has been developed by the U.S. EPA that is capable of addressing the atmospheric fate, transport and deposition of some common trace toxics. An initial, 36-km rectangular grid-cell application for atrazine has been...

ATRAZINE-INDUCED REPRODUCTIVE TRACT ALTERATIONS AFTER TRANSPLACENTAL AND LACTATIONAL EXPOSURE IN LONG-EVANS RAT PUPS

EPA Science Inventory

Studies have shown that early postnatal exposure to the common herbicide atrazine (ATR) will delay preputial separation (PPS) in Wistar rats and increase incidence of prostate inflammation in adults. To evaluate ATR exposure parameters required for pubertal delays (PPS), we used...

ATRAZINE DISPOSITION IN PREGNANT AND LACTATING LONG-EVANS RATS

EPA Science Inventory

Atrazine (ATR) is a widely used herbicide shown to delay early mammary development in female offspring of gestationally exposed rats. The effects of ATR can be induced by in utero exposure and/or suckling from a dam exposed during late pregnancy, but ATR is reported to have a hal...

ATRAZINE-INDUCED REPRODUCTIVE TRACT ALTERATIONS AFTER TRANSPLACENTAL AND LACTATIONAL EXPOSURE IN MALE LONG-EVANS RATS.

EPA Science Inventory

Studies showed that early postnatal exposure to the herbicide atrazine (ATR) delayed preputial separation (PPS) and increased incidence of prostate inflammation in adult Wistar rats. A cross-fostering paradigm was used in this study to determine if gestational exposure to ATR wou...

MAMMARY GLAND DEVELOPMENT AS A SENSITIVE END-POINT FOLLOWING ACUTE PERNATAL EXPOSURE TO A LOW DOSE ATRAZINE METABOLITE MIXTURE IN FEMALE LONG EVANS RATS

EPA Science Inventory

In order to characterize the potential developmental effects of atrazine (ATR) metabolites at low doses, an environmentally-based mixture (EBM) of ATR and its metabolites hydroxyatrazine, diaminochlorotriazine, deethylatrazine, and deisopropylatrazine was formulated based on surv...

Effect of 2,4-D and atrazine when applied with glyphosate ripener

USDA-ARS?s Scientific Manuscript database

Management of late-season morningglory infestations in sugarcane is accomplished with aerial applications of the postemergence herbicides 2,4-D, dicamba, or atrazine. Likewise, the aerial application of glyphosate prior to harvest to improve stalk sucrose levels is a common practice for many Louisia...

IMMUNOASSAY METHODS FOR MEASURING ATRAZINE AND 3,5,6-TRICHLORO-2-PYRIDINOL IN FOODS

EPA Science Inventory

This chapter describes the use of enzyme-linked immunosorbent assay (ELISA) methods for the analysis of two potential environmental contaminants in food sample media, atrazine and 3,5,6-trichloro-2-pyridinol (3,5,6-TCP). Two different immunoassay formats are employed: a magnetic...

Gestational exposure to atrazine has little effect on female reproductive parameters in Sprague-Dawley (SD) rats

EPA Science Inventory

Atrazine (ATR), a commonly used herbicide, has been shown to exert reproductive effects in animals; however, most ofthese studies have focused on adult exposure. In contrast, there is limited information available on the reproductive and developmental effects of gestational expos...

A NEW APPROACH FOR CULTURING LEMNA MINOR (DUCKWEED) AND STANDARDIZED METHOD FOR USING ATRAZINE AS A REFERENCE TOXICANT

EPA Science Inventory

Lemna minor (Duckweed) is commonly used in aquatic toxicity investigations. Methods for culturing and testing with reference toxicants, such as atrazine, are somewhat variable among researchers. Our goal was to develop standardized methods of culturing and testing for use with L....

MATERNAL ATRAZINE (ATR) ALTERS HYPOTHALAMIC DOPAMINE (HYP-DA) AND SERUM PROLACTIN (SPRL) IN MALE PUPS

EPA Science Inventory

Maternal Atrazine (ATR) alters hypothalamic dopamine (HYP-DA) and serum prolactin (sPRL) in male pups. 1Christopher Langdale, 2Tammy Stoker and 2Ralph Cooper. 1 Dept. of Cell Biology, North Carolina State University College of Veterinary Medicine, Raleigh, NC. 2 Endocrinology ...

Differences in Uptake, Metabolism and Clearance of Atrazine and Tamoxifen in a Fish and a Rat Species

EPA Science Inventory

Atrazine and tamoxifen are known endocrine-disrupting chemicals (EDCs) that have metabolites exhibiting biological activities that are equally or more potent than the parent compound. To evaluate if uptake, metabolism and clearance of such EDCs is a concern in interspecies extrap...

Differences in Uptake, Metabolism and Clearance ofAtrazine and Tamoxifen in a Fish and a Rat Species

EPA Science Inventory

Atrazine and tamoxifen are known endocrine-disrupting chemicals (EDCs) that have metabolites exhibiting biological activities that are equally or more potent than the parent compound. To evaluate if uptake, metabolism and clearance of such EDCs is a concern in interspecies extrap...

LATE GESTATIONAL ATRAZINE EXPOSURE DECREASES MATERNAL BEHAVIOR IN LONG-EVANS RATS

EPA Science Inventory

Late Gestational Atrazine Exposure Alters Maternal Nursing Behavior in Rats

Jennifer L. Rayner1 and Suzanne E. Fenton2

1 University of North Carolina at Chapel Hill, DESE, Chapel Hill, NC, and 2 USEPA/ ORD/NHEERL/Reproductive Toxicology Division, RTP, NC.

At...

Charcterization of the Hypothalamic-Pituitary-Adrenal Axis Response to Atrazine and Metabolites in the Female Rat

EPA Science Inventory

Atrazine (ATR) has recently been shown to activate the hypothalamic-pituitary-adrenal (HPA) axis in rodents. The current study investigated the effect of ATR and two of its chlorinated metabolites, desisopropylatrazine (DIA) and diamino-s-chlorotriazine (DACT), on the HPA axis in...

A Discussion of Water Pollution in the United States and Mexico; with High School Laboratory Activities for Analysis of Lead, Atrazine, and Nitrate.

ERIC Educational Resources Information Center

Kelter, Paul B.; Grundman, Julie; Hage, David S.; Carr, James D.; Castro-Acuna, Carlos Mauricio

1997-01-01

Presents discussions on sources, health impacts, methods of analysis as well as lengthy discussions of lead, nitrates, and atrazine as related to water pollution and the interdisciplinary nature of the modern chemistry curriculum. (DKM)

Dissipation of atrazine, enrofloxacin, and sulfamethazine in wood chip bioreactors and impact on denitrification

USDA-ARS?s Scientific Manuscript database

Wood chip bioreactors are receiving increasing attention as a means of reducing nitrate in subsurface tile drainage systems. Agrochemicals in tile drainage water entering wood chip bioreactors can be retained or degraded and may impact denitrification. The degradation of 5 mg L-1 atrazine, enrofloxa...

Effect of flood-induced chemical load on filtrate quality at bank filtration sites

USGS Publications Warehouse

Ray, C.; Soong, T.W.; Lian, Y.Q.; Roadcap, G.S.

2002-01-01

Riparian municipal wells, that are located on riverbanks, are specifically designed to capture a portion of the river water through induced infiltration. Runoff from agricultural watersheds is found to carry enormous amounts of pesticides and nitrate. While the risk of contamination for a vast majority of sites with small-capacity vertical wells is low, potential exists for medium to large capacity collector wells to capture a fraction of the surface water contaminants during flood. Prior monitoring and current modeling results indicate that a small-capacity (peak pumpage 0.0315 m3/s) vertical bank filtration well may not be affected by river water nitrate and atrazine even during flood periods. For a medium capacity (0.0875-0.175 m3/s) hypothetical collector well at the same site, potential exists for a portion of the river water nitrate and atrazine to enter the well during flood periods. Various combinations of hydraulic conductivity of the riverbed or bank material were used. For nitrate, it was assumed either no denitrification occurred during the period of simulation or a half-life of 2 years. Equilibrium controlled sorption (organic carbon partition coefficient of 52 ml/g) and a half-life of between 7.5 and 15 weeks were considered for atrazine. Combinations of these parameters were used in various simulations. Peak concentrations of atrazine or nitrate in pumped water could vary from less than 1% to as high as 90% of that in the river. It was found that a combination of river stage, pumping rates, hydraulic properties of the riverbed and bank, and soil/pesticide properties could affect contaminant entry from river water to any of these wells. If the hydraulic conductivity of the bed and bank material were low, atrazine would not reach the pumping well with or without sorption and degradation. However, for moderately low permeable bank and bed materials, some atrazine from river water could enter a hypothetical collector well while pumping at 0.0875 m3/s. It was interesting to note that doubling the pumpage of this collector well would bring in more ground water from the aquifer (with no atrazine) and thus have a lower concentration of atrazine in the filtrate. For highly conductive banks, it is possible to find some atrazine at a vertical well for a sustained pumpage rate of 0.0125 m3/s if the effect of sorption is neglected. However, with equilibrium sorption, the concentration would be below the detection limit. On the other hand, if a collector well of capacity 0.0875 m3/s is used at the place of the vertical well with highly conductive banks, atrazine concentration in the filtrate would be about 80% of river water even assuming equilibrium sorption and a half-life of 7.5 weeks. Remediation of river water contamination of the aquifer using 'scavenger' wells between the river and the pumping well(s) was not a feasible option due to the contact of the aquifer with a highly conductive bank at the site. However, moving the existing pumping well(s) 100 m upstream would have negligible impact from the bank-stored water. ?? 2002 Elsevier Science B.V. All rights reserved.

Exploring Education and Training Needs in Palliative Care among Family Physicians in Mumbai: A Qualitative Study.

PubMed

Damani, Anuja; Ghoshal, Arunangshu; Dighe, Manjiri; Dhiliwal, Sunil; Muckaden, Maryann

2018-01-01

Patients with chronic life-limiting conditions on palliative care (PC) prefer to be treated at home. Medical care by family physicians (FPs) reduces demand on costly and busy hospital facilities. Working of PC team in collaboration with FPs is thus helpful in home-based management of patients. This study aimed at exploring the extent of knowledge of FPs about PC and the need for additional training. Semi-structured interviews were conducted with ten FPs from two suburbs of Mumbai, currently served by home care services of a tertiary cancer care center. Data were digitally recorded, transcribed, and analyzed using exploratory analysis followed by content analysis to develop thematic codes. FPs perceive PC as symptom control and psychological support helpful in managing patients with advanced life-limiting illnesses. Further training would help them in PC provision. Such training programs should preferably focus on symptom management and communication skills. There is a need for further research in designing a training module for FPs to get better understanding of the principles of PC.

Exploring Education and Training Needs in Palliative Care among Family Physicians in Mumbai: A Qualitative Study

PubMed Central

Damani, Anuja; Ghoshal, Arunangshu; Dighe, Manjiri; Dhiliwal, Sunil; Muckaden, Maryann

2018-01-01

Context: Patients with chronic life-limiting conditions on palliative care (PC) prefer to be treated at home. Medical care by family physicians (FPs) reduces demand on costly and busy hospital facilities. Working of PC team in collaboration with FPs is thus helpful in home-based management of patients. Aims: This study aimed at exploring the extent of knowledge of FPs about PC and the need for additional training. Settings and Design: Semi-structured interviews were conducted with ten FPs from two suburbs of Mumbai, currently served by home care services of a tertiary cancer care center. Subjects and Methods: Data were digitally recorded, transcribed, and analyzed using exploratory analysis followed by content analysis to develop thematic codes. Results and Conclusions: FPs perceive PC as symptom control and psychological support helpful in managing patients with advanced life-limiting illnesses. Further training would help them in PC provision. Such training programs should preferably focus on symptom management and communication skills. There is a need for further research in designing a training module for FPs to get better understanding of the principles of PC. PMID:29736114

Dynamic Forces in Spur Gears - Measurement, Prediction, and Code Validation

NASA Technical Reports Server (NTRS)

Oswald, Fred B.; Townsend, Dennis P.; Rebbechi, Brian; Lin, Hsiang Hsi

1996-01-01

Measured and computed values for dynamic loads in spur gears were compared to validate a new version of the NASA gear dynamics code DANST-PC. Strain gage data from six gear sets with different tooth profiles were processed to determine the dynamic forces acting between the gear teeth. Results demonstrate that the analysis code successfully simulates the dynamic behavior of the gears. Differences between analysis and experiment were less than 10 percent under most conditions.

MicroRNAs as Biomarkers for Diagnosis, Prognosis and Theranostics in Prostate Cancer

PubMed Central

Bertoli, Gloria; Cava, Claudia; Castiglioni, Isabella

2016-01-01

Prostate cancer (PC) includes several phenotypes, from indolent to highly aggressive cancer. Actual diagnostic and prognostic tools have several limitations, and there is a need for new biomarkers to stratify patients and assign them optimal therapies by taking into account potential genetic and epigenetic differences. MicroRNAs (miRNAs) are small sequences of non-coding RNA regulating specific genes involved in the onset and development of PC. Stable miRNAs have been found in biofluids, such as serum and plasma; thus, the measurement of PC-associated miRNAs is emerging as a non-invasive tool for PC detection and monitoring. In this study, we conduct an in-depth literature review focusing on miRNAs that may contribute to the diagnosis and prognosis of PC. The role of miRNAs as a potential theranostic tool in PC is discussed. Using a meta-analysis approach, we found a group of 29 miRNAs with diagnostic properties and a group of seven miRNAs with prognostic properties, which were found already expressed in both biofluids and PC tissues. We tested the two miRNA groups on The Cancer Genome Atlas dataset of PC tissue samples with a machine-learning approach. Our results suggest that these 29 miRNAs should be considered as potential panel of biomarkers for the diagnosis of PC, both as in vivo non-invasive test and ex vivo confirmation test. PMID:27011184

Regulation of STATs by polycystin-1 and their role in polycystic kidney disease.

PubMed

Weimbs, Thomas; Olsan, Erin E; Talbot, Jeffrey J

2013-04-01

Autosomal-dominant polycystic kidney disease (ADPKD) is a common genetic disease caused by mutations in the gene coding for polycystin-1 (PC1). PC1 can regulate STAT transcription factors by a novel, dual mechanism. STAT3 and STAT6 are aberrantly activated in renal cysts. Genetic and pharmacological approaches to inhibit STAT3 or STAT6 have led to promising results in ADPKD mouse models. Here, we review current findings that lead to a model of PC1 as a key regulator of STAT signaling in renal tubule cells. We discuss how PC1 may orchestrate appropriate epithelial responses to renal injury, and how this system may lead to aberrant STAT activation in ADPKD thereby causing inappropriate activation of tissue repair programs that culminate in renal cyst growth and fibrosis.

Identification and functional characterization of an uncharacterized antimicrobial peptide from a ciliate Paramecium caudatum.

PubMed

Cui, Pengfei; Dong, Yuan; Li, Zhijian; Zhang, Yubo; Zhang, Shicui

2016-07-01

The global ever-growing concerns about multi-drug resistant (MDR) microbes leads to urgent demands for exploration of new antibiotics including antimicrobial peptides (AMPs). Here we demonstrated that a cDNA from Ciliata Paramecium caudatum, designated Pcamp1, coded for a protein with features characteristic of AMPs, which is not homologous to any AMPs currently known. Both the C-terminal 91 amino acid residues of PcAMP1, cPcAMP1, expressed in Escherichia coli and the C-terminal 26 amino acid residues (predicted mature AMP), cPcAMP1/26, synthesized, underwent a coil-to-helix transition in the presence of TFE, SDS or DPC. Functional assays revealed that cPcAMP1 and cPcAMP1/26 were both able to kill Aeromonas hydrophila and Staphylococcus aureus. ELISA showed that cPcAMP1 and cPcAMP1/26 were able to bind to microbe-associated molecular pattern molecules LPS and LTA, which was further corroborated by the observations that cPcAMP1 could deposit onto the bacterial membranes. Importantly, both cPcAMP1 and cPcAMP1/26 were able to induce bacterial membrane permeabilization and depolarization, and to increase intracellular ROS levels. Additionally, cPcAMP1 and cPcAMP1/26 were not cytotoxic to mammalian cells. Taken together, our results show that PcAMP1 is a potential AMP with a membrane selectivity towards bacterial cells, which renders it a promising template for the design of novel peptide antibiotics against MDR microbes. It also shows that use of signal conserved sequence of AMPs can be an effective tool to identify potential AMPs across different animal classes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The interaction of long non-coding RNA MIAT and miR-133 play a role in the proliferation and metastasis of pancreatic carcinoma.

PubMed

Li, Ting-Fu; Liu, Jian; Fu, Shi-Jie

2018-05-14

Pancreatic cancer (PC) is one of the most aggressive malignancies in humans. Despite advances in early detection and treatment of PC, the prognosis is still limited. LncRNA myocardial infarction-associated transcript (MIAT) is found abnormally expressed in a variety of cancers. However, the role of MIAT in PC is still unknown. This study aimed to explore whether MIAT was related to the progression of PC and the underlying mechanism. Bioinformatics analysis and luciferase reporter assay validated that miR-133 may target MIAT 3'-UTR. MIAT expression was found remarkably increased and miR-133 expression was significantly decreased in PC tissues and PC cell lines (PATU-8988, BxPC-3, PANC-1, SW1990 and AsPC-1 cells). PC patients with high MIAT level had poor prognosis than that with low MITA level. Besides that, PATU-8988 cells transfected with siMIAT and/or miR-133 inhibitor. The results exhibited that the inhibition of miR-133 expression reversed the inhibition effect of MIAT down-regulation in the growth, migration and invasion of PC cells. Moreover, tumor growth was tremendously suppressed in nude rats received injection of PATU-8988 cells transfected with siMIAT. Taken together, our results suggest that the interaction of MIAT and miR-133 play a role in the proliferation and metastasis of pancreatic carcinoma. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

PERINATAL EXPOSURE TO ATRAZINE SUPPRESSES JUVENILE IMMUNE FUNCTION IN MALE, BUT NOT FEMALE SPRAGUE-DAWLEY RATS

EPA Science Inventory

PERINATAL EXPOSURE TO ATRAZINE SUPPRESSES JUVENILE IMMUNE FUNCTION IN MALE, BUT NOT FEMALE SPRAGUE-DAWLEY RATS. AA Rooney1 and RW Luebke2. 1NCSU/USEPA CVM, Department of Anatomy, Physiological Sciences, and Radiology, Raleigh, NC;2USEPA, NHEERL, RTP, NC.
The ability of the ...

76 FR 25281 - Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Proposed Tolerance Actions

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

... use of profanity or personal threats. viii. Make sure to submit your comments by the comment period... atrazine, establish tolerances for endosulfan, and make minor revisions to tolerance expressions for a few..., 2011. ADDRESSES: Submit your comments, identified by docket identification (ID) number EPA-HQ-OPP-2011...

Effects of an atrazine, metolachlor, and fipronil mixture on Hyalella azteca (Saussure) in a modified backwater wetland

USDA-ARS?s Scientific Manuscript database

We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a mixture of three pesticides, atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first two hours...

MEASURED CONCENTRATIONS OF HERBICIDES AND MODEL PREDICTIONS OF ATRAZINE FATE IN THE PATUXENT RIVER ESTUARY

EPA Science Inventory

McConnell, Laura L., Jennifer A. Harman-Fetcho and James D. Hagy, III. 2004. Measured Concentrations of Herbicides and Model Predictions of Atrazine Fate in the Patuxent River Estuary. J. Environ. Qual. 33(2):594-604. (ERL,GB X1051).

The environmental fate of herbicides i...

Atrazine-induced elevation or attenuation of the LH surge in the ovariectomized, estrogen-primed female rat: role of adrenal progesterone

EPA Science Inventory

Multiple daily exposures to the herbicide atrazine have been reported to suppress the surge of luteinizing hormone (LH) in both cycling female rats and those that are ovariectomized (OVX) and exogenously primed with steroids. Additional studies have also found elevations in both ...

Strain Differences in Dimethylbenz[a]anthracene-Induced Mammary Tumor Incidence in Long Evans and Sprague Dawley Rat Offspring Following Prenatal Atrazine Exposure

EPA Science Inventory

It has been shown that prenatal exposure to the chlorotriazine herbicide atrazine (ATR) during mammary bud outgrowth (late gestation) delays postnatal mammary epithelial progression in Long Evans (LE) rats. Our laboratory has recently found that prenatal exposure to ATR also effe...

ATRAZINE DOES NOT INDUCE GASTROINTESTINAL DISCOMFORT (PICA) IN RATS AT DOSES THAT INCREASE HPA-AXIS ACTIVATION AND CAUSE CONDITIONED TASTE AVERSION.

EPA Science Inventory

Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH) and serum corticosterone (CORT), with a NOEL equal to 5mg/kg. The mechanism for these effects ...

Mammary gland development and response to prenatal atrazine exposure in the Sprague Dawley and Long-Evans rats.

EPA Science Inventory

Mammary gland (MG) tumor development in Sprague Dawley (SD) rats is increased by longterm dietary exposure to the chlorotriazine herbicide atrazine (ATR). ATR is proposed to cause these changes in the adult SD rat by altering hormonally-regulated estrous cyclicity. In Long-Evans...

RESPONSES OF MOLECULAR INDICATORS OF EXPOSURE IN MESOCOSMS: COMMON CARP (CYPRINUS CARPIO) EXPOSED TO THE HERBICIDES ALACHLOR AND ATRAZINE

EPA Science Inventory

Common carp (Cyprinus carpio) were treated in aquatic mesocosms with a single pulse of the herbicides atrazine or alachlor to study the bioavailability and biological activity of these herbicides using molecular indicators: Liver vitellogenin gene expression in male fish for estr...

ATRAZINE ALTERS STEROIDOGENESIS IN MALE WISTAR RATS

EPA Science Inventory

We have reported that atrazine (ATR, 200 mg/kg x 30 d) causes increased serum estrone (E) and estradiol (E2) in male wistar rats (Toxicol. Sci. 2000, 58:50-59). This study evaluates the short-term effects of ATR on E, E2 and their precursors in the steroidogenic pathway. Sixty-da...

ATRAZINE INCREASES DIMETHYLBENZ[A]ANTHRACENE-INDUCED MAMMARY TUMOR INCIDENCE IN LONG EVANS OFFSPRING EXPOSED IN UTERO

EPA Science Inventory

ATRAZINE INCREASES DIMETHYLBENZ[A]ANTHRACENE-INDUCED MAMMARY TUMOR INCIDENCE IN LONG EVANS OFFSPRING EXPOSED IN UTERO.

SE Fenton and CC Davis

Reproductive Toxicology Division, NHEERL, ORD, USEPA, Durham, NC, USA

Recently, we found that ATR exposure during ma...

EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND ITS METABOLITES IN MALE LONG EVANS RATS

EPA Science Inventory

TITLE: EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND IT'S BIOLOGICAL METABOLITES IN MALE LONG EVANS RATS. Suzanne E. Fenton 1, Sara N. Greiner 1, Geri L. Youngblood 1 and Christine C. Davis 1
1 U.S. Environmental Protection Agency, Reproductive Toxicology Divi...

DETECTION OF A CRITICAL PERIOD NECESSARY FOR ATRAZINE-INDUCED MAMMARY GLAND DELAYS IN RATS

EPA Science Inventory

Detection of a Critical Period Necessary for Atrazine-Induced Mammary Gland Delays in Rats.

Jennifer L. Rayner1 and Suzanne E. Fenton2

1 University of North Carolina at Chapel Hill, DESE, Chapel Hill, NC, and 2 Reproductive Toxicology Division, USEPA, NHEERL/ORD, R...

ADVERSE EFFECTS OF PRENATAL EXPOSURE TO ATRAZINE DURING A CRITICAL PERIOD OF MAMMARY GLAND GROWTH

EPA Science Inventory

Prenatal exposure to 100 mg/kg atrazine (ATR) was previously shown to delay mammary gland (MG) development in the female offspring of Long Evans (LE) rats. To determine if the fetal MG was most sensitive to ATR effects during specific periods of development, timed-pregnant dams ...

PUBERTAL DEVELOPMENT IN FEMALE WISTAR RATS FOLLOWING EXPOSURE TO PROPAZINE AND ATRAZINE BIOTRANSFORMATION BY-PRODUCTS, DIAMINO-S-CHLOROTRIAZINE AND HYDROXYATRAZINE

EPA Science Inventory

We have shown previously that the chlorotriazine herbicide, atrazine (ATR), delays the onset of pubertal development in female rats. ATR and its by-products of microbial degradation are present in soil and groundwater. Since current maximum contaminant levels are set only for ATR...

PUBERTAL DEVELOPMENT IN FEMALE WISTAR RATS FOLLOWING EXPOSURE TO PROPAZINE AND ATRAZINE METABOLITES, DIAMINO-S-CHLOROTRIAZINE AND HYDROXYATRAZINE

EPA Science Inventory

PUBERTAL DEVELOPMENT IN FEMALE WISTAR RATS FOLLOWING EXPOSURE TO PROPAZINE AND ATRAZINE METABOLITES, DIAMINO-S-CHLOROTRIAZINE AND HYDROXYATRAZINE. S C Laws, J M Ferrell, T E Stoker, and R L Cooper. Endocrinology Branch, RTD, NHEERL, ORD, USEPA, RTP, NC, USA. Sponser: R J K...

Effects of agricultural and residential land use on ground-water quality, Anoka Sand Plain Aquifer, east-central Minnesota

USGS Publications Warehouse

Anderson, H.W.

1993-01-01

Triazine herbicides were detected in 11 of 18 samples analyzed for pesticides. Concentrations of atrazine were less than the 3 (J-g/L maximum contaminant level set for atrazine by the Minnesota Department of Health and by the U.S. Environmental Protection Agency.

Movements of water, solutes, and stable isotopes in the unsaturated zones of two sand plains in the upper Midwest

USGS Publications Warehouse

Komor, Stephen C.; Emerson, Douglas G.

1994-01-01

Four month-long field experiments investigated movements of water and solutes through unsaturated sand plains near Princeton, Minnesota, and Oakes, North Dakota. Atrazine and bromide were applied to bare soils and soils planted with corn. The field plots were irrigated according to local farming practices. At the end of each experiment, unsaturated soils were analyzed for atrazine and bromide concentrations and oxygen and hydrogen isotope compositions of soil water. Most soil water was affected by evaporation but groundwater beneath the plots had no evaporative isotopic signature. Therefore most recharge consisted of water that was unaffected by evaporation. Sources of such water may have included snowmelt, prolonged or high-intensity rainfalls that were not interrupted by periods of drying, and water that moved through preferential flow paths. Preferential flow also was suggested by the detection of atrazine, deethylatrazine, and bromide in groundwater shortly after each application of irrigation water at Princeton and by isolated concentrations of atrazine and bromide in soil well below the main masses of chemicals at Oakes.

Preferential dealkylation reactions of s-triazine herbicides in the unsaturated zone

USGS Publications Warehouse

Mills, M.S.; Michael, Thurman E.

1994-01-01

The preferential dealkylation pathways of the s-triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], and two monodealkylated triazine metabolites, deisopropylatrazine (DIA: 2-amino-4-chloro-6-ethylamino-s-triazine) and deethylatrazine (DEA: 2-amino-4-chloro-6-isopropylamino-s-triazine) were investigated on two adjacent Eudora silt-loam plots growing corn (Zea mays L.). Results from the shallow unsaturated zone and surface-water runoff showed preferential removal of an ethyl side chain from atrazine, simazine, and DIA relative to an isopropyl side chain from atrazine, propazine, and DEA. It is hypothesized that deethylation reactions may proceed at 2-3 times the rate of deisopropylation reactions. It is concluded that small concentrations of DIA reportedly associated with the degradation of atrazine may be due to a rapid turnover rate of the metabolite in the unsaturated zone, not to small production levels. Because of continued dealkylation of both monodealkylated metabolites, a strong argument is advanced for the presence of a didealkylated metabolite in the unsaturated zone.

LEOPARD on a personal computer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lancaster, D.B.

1988-01-01

The LEOPARD code is very widely used to produce four- or two-group cross sections for water reactors. Although it is heavily used it had not been downloaded to the PC. This paper has been written to announce the completion of downloading LEOPARD. LEOPARD can now be run on anything from the early PC to the most advanced 80386 machines. The only requirements are 512 Kbytes of memory (LEOPARD actually only needs 235, but with buffers, 256 Kbytes may not be enough) and two disk rives (preferably, one is a hard drive). The run times for various machines and configurations aremore » summarized. The accuracy of the PC-LEOPARD results are documented.« less

A highly sensitive immunoassay for atrazine based on covalently linking the small molecule hapten to a urea-glutaraldehyde network on a polystyrene surface.

PubMed

Sai, Na; Sun, Wenjing; Wu, Yuntang; Sun, Zhong; Yu, Guanggui; Huang, Guowei

2016-11-01

A new enzyme-linked immunosorbent assay (ELISA) for atrazine was developed based on covalent bonding of the small molecule hapten, 2-mercaptopropionic acid-4-ethylamino-6-isopropylamino-1,3,5-triazine (MPA-atrazine), to urea-glutaraldehyde (UGA)-treated microtiter plates. In this assay, the microtiter plate surface was treated with the UGA network to both introduce amino groups, which were used to cross-link with the hapten carboxylate groups, and efficiently prevent non-specific adsorption of antibodies, which successfully eliminated the time-consuming routine blocking step. Compared with HNO 3 -H 2 SO 4 -APTES-hapten coated ELISA (modified with a HNO 3 -H 2 SO 4 -APTES mixture and covalent-linked hapten) and conventional ELISA (coated with hapten-carrier protein conjugates), the novel ELISA format increased the sensitivity by approximately 3.5-fold and 7.5-fold, respectively, and saved 2.5h and 34h of coating hapten time, respectively. The method's 50% inhibition concentration for atrazine was 5.54ngmL -1 , and the limit of detection was 0.16ngmL -1 after optimization of reaction conditions. Furthermore, the ELISA was adapted for analysis of atrazine in corn, rice, and water samples, demonstrating recoveries of 90%-108%. Thus, the assay provides a convenient alternative to conventional, laborious immunoassays for routine supervision of residue detection in food and the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

A simple method for isolation and purification of DIBOA-Glc from Tripsacum dactyloides.

PubMed

Willett, Cammy D; Lerch, Robert N; Goyne, Keith W; Leigh, Nathan D; Lin, Chung-Ho; Roberts, Craig A

2014-09-01

Naturally occurring benzoxazinones (Bx) are a highly reactive class of compounds that have received particular attention in the past several decades. Recently, we identified 2-β-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DIBOA-Glc) as the compound present in the roots of Eastern gamagrass {Tripsacum dactyloides (L.)} responsible for atrazine degradation. However, characterization of the DIBOA-Glc/atrazine degradation reaction has been limited due to difficulties in attaining sufficient quantities of purified DIBOA-Glc. The objective of the study was to develop a simple purification and isolation method for obtaining bulk quantities of highly purified DIBOA-Glc. T. dactyloides roots were extracted with 90% aqueous methanol, and the crude extract was fractionated using an HPLC equipped with a C8 semi-prep column and fraction collector. UHPLC-DAD-MS/MS was used to confirm the identity of DIBOA-Glc in the fractions collected. Analysis by 13C and 1H NMR and DAD indicated that 542 mg of DIBOA-Glc with a purity of > 99% was obtained. The reactivity of the DIBOA-Glc was confirmed in a 16 hour assay with atrazine, which resulted in 48.5% ± 1.2% (SD) atrazine degradation. The method described here offers several advantages over existing extraction and synthesis methods, which are more cumbersome, use hazardous chemicals, and yield only small quantities of purified compound. The newly developed method will facilitate future research characterizing the chemical behavior of DIBOA-Glc and determine its potential as an atrazine mitigation and remediation tool.

Pilot-scale treatment of atrazine production wastewater by UV/O3/ultrasound: Factor effects and system optimization.

PubMed

Jing, Liang; Chen, Bing; Wen, Diya; Zheng, Jisi; Zhang, Baiyu

2017-12-01

This study shed light on removing atrazine from pesticide production wastewater using a pilot-scale UV/O 3 /ultrasound flow-through system. A significant quadratic polynomial prediction model with an adjusted R 2 of 0.90 was obtained from central composite design with response surface methodology. The optimal atrazine removal rate (97.68%) was obtained at the conditions of 75 W UV power, 10.75 g h -1 O 3 flow rate and 142.5 W ultrasound power. A Monte Carlo simulation aided artificial neural networks model was further developed to quantify the importance of O 3 flow rate (40%), UV power (30%) and ultrasound power (30%). Their individual and interaction effects were also discussed in terms of reaction kinetics. UV and ultrasound could both enhance the decomposition of O 3 and promote hydroxyl radical (OH·) formation. Nonetheless, the dose of O 3 was the dominant factor and must be optimized because excess O 3 can react with OH·, thereby reducing the rate of atrazine degradation. The presence of other organic compounds in the background matrix appreciably inhibited the degradation of atrazine, while the effects of Cl - , CO 3 2- and HCO 3 - were comparatively negligible. It was concluded that the optimization of system performance using response surface methodology and neural networks would be beneficial for scaling up the treatment by UV/O 3 /ultrasound at industrial level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Does area deprivation modify the association between exposure to a nitrate and low-dose atrazine metabolite mixture in drinking water and small for gestational age? A historic cohort study.

PubMed

Limousi, F; Albouy-Llaty, M; Carles, C; Dupuis, A; Rabouan, S; Migeot, V

2014-04-01

Birth weight may be influenced by environmental and socio-economic factors that could interact. The main objective of our research was to investigate whether area deprivation may modify the association between drinking water exposure to a mixture of atrazine metabolites and nitrates during the second trimester of pregnancy and prevalence of small for gestational age (SGA) neonates. We conducted a historic cohort study in Deux-Sèvres, France between 2005 and 2010, using birth records, population census and regularly performed drinking water withdrawals at community water systems. Exposure to an atrazine metabolite/nitrate mixture in drinking water was divided into six classes according to the presence or absence of atrazine metabolites and to the terciles of nitrate concentrations in each trimester of pregnancy. We used a logistic regression to model the association between SGA and mixture exposure at the second trimester while taking into account the area deprivation measured by the Townsend index as an effect modifier and controlling for the usual confounders. We included 10,784 woman-neonate couples. The risk of SGA when exposed to second tercile of nitrate without atrazine metabolites was significantly greater in women living in less deprived areas (OR = 2.99; 95 % CI (1.14, 7.89)), whereas it was not significant in moderately and more deprived areas. One of the arguments used to explain this result is the presence of competing risk factors in poorer districts.

Fate and risk of atrazine and sulfentrazone to nontarget species at an agriculture site.

PubMed

Thorngren, Jordan L; Harwood, Amanda D; Murphy, Tracye M; Huff Hartz, Kara E; Fung, Courtney Y; Lydy, Michael J

2017-05-01

The present study evaluated the risk associated with the application and co-occurrence of 2 herbicides, atrazine and sulfentrazone, applied to a 32-ha corn and soybean rotational field. Field concentrations of the compounds were measured in soil, runoff water, and groundwater, with peak mean atrazine and sulfentrazone concentrations found in the soil (144 ng/g dry wt, and 318 ng/g dry wt, respectively). Individual and mixture laboratory bioassays were conducted to determine the effects of atrazine and sulfentrazone on the survival of Daphnia magna and Pimephales promelas, the germination of Lactuca sativa, and the growth of Pseudokirchneriella subcapita and Lemna minor. Pseudokirchneriella subcapita and L. minor were the most susceptible species tested, and the effects on growth of the herbicides in mixtures best fit an independent action model. Risk quotients and margin of safety of 10% (MOS10) values were used to estimate risk and were calculated using runoff water concentrations. The MOS10 values were more sensitive than risk quotients in estimating risk. The MOS10 value for sulfentrazone runoff water concentration effects on P. subcapita was 7.8, and for L. minor was 1.1, with MOS10 values < 1 indicating potential risk. Overall, the environmentally relevant concentrations fell below the effect concentrations; therefore, atrazine and sulfentrazone posed little to no risk to the nontarget species tested. Environ Toxicol Chem 2017;36:1301-1310. © 2016 SETAC. © 2016 SETAC.

Market-level assessment of the economic benefits of atrazine in the United States

PubMed Central

Mitchell, Paul D

2014-01-01

BACKGROUND Atrazine and other triazine herbicides are widely used in US maize and sorghum production, yet the most recent market-level assessment of the economic benefits of atrazine is for market conditions prevalent in the early 1990s, before commercialization of transgenic crops. Grain markets have changed substantially since that time; for example, the size of the US maize market increased by 170% from 1990–1992 to 2007–2009. This paper reports a current assessment of the economic benefits of atrazine. RESULTS Yield increases and cost changes implied by triazine herbicides are projected to reduce maize prices by 7–8% and sorghum prices by 19–20%. Projected consumer benefits from lower prices range from $US 3.6 to 4.4 × 109 annually, with the net projected economic benefit for triazine herbicides to the US economy ranging from $US 2.9 to 3.4 × 109 annually because lower prices imply reduced producer income. Productivity gains from triazine herbicides maintain an estimated 270 000–390 000 ha of land in non-crop uses that generate environmental benefits not accounted for in this analysis. CONCLUSION Even in the current era, with transgenic varieties dominating crop production, atrazine and the other triazine herbicides continue to be a key part of maize and sorghum production and generate substantial economic benefits. © 2013 The Authors. PestManagement Science published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:24318916

Market-level assessment of the economic benefits of atrazine in the United States.

PubMed

Mitchell, Paul D

2014-11-01

Atrazine and other triazine herbicides are widely used in US maize and sorghum production, yet the most recent market-level assessment of the economic benefits of atrazine is for market conditions prevalent in the early 1990s, before commercialization of transgenic crops. Grain markets have changed substantially since that time; for example, the size of the US maize market increased by 170% from 1990-1992 to 2007-2009. This paper reports a current assessment of the economic benefits of atrazine. Yield increases and cost changes implied by triazine herbicides are projected to reduce maize prices by 7-8% and sorghum prices by 19-20%. Projected consumer benefits from lower prices range from $US 3.6 to 4.4 × 10(9) annually, with the net projected economic benefit for triazine herbicides to the US economy ranging from $US 2.9 to 3.4 × 10(9) annually because lower prices imply reduced producer income. Productivity gains from triazine herbicides maintain an estimated 270 000-390 000 ha of land in non-crop uses that generate environmental benefits not accounted for in this analysis. Even in the current era, with transgenic varieties dominating crop production, atrazine and the other triazine herbicides continue to be a key part of maize and sorghum production and generate substantial economic benefits. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Natural variation reveals relationships between pre-stress carbohydrate nutritional status and subsequent responses to xenobiotic and oxidative stress in Arabidopsis thaliana.

PubMed

Ramel, Fanny; Sulmon, Cécile; Gouesbet, Gwenola; Couée, Ivan

2009-12-01

Soluble sugars are involved in responses to stress, and act as signalling molecules that activate specific or hormone cross-talk transduction pathways. Thus, exogenous sucrose treatment efficiently induces tolerance to the herbicide atrazine in Arabidopsis thaliana plantlets, at least partially through large-scale modifications of expression of stress-related genes. Availability of sugars in planta for stress responses is likely to depend on complex dynamics of soluble sugar accumulation, sucrose-starch partition and organ allocation. The question of potential relationships between endogenous sugar levels and stress responses to atrazine treatment was investigated through analysis of natural genetic accessions of A. thaliana. Parallel quantitative and statistical analysis of biochemical parameters and of stress-sensitive physiological traits was carried out on a set of 11 accessions. Important natural variation was found between accessions of A. thaliana in pre-stress shoot endogenous sugar levels and responses of plantlets to subsequent atrazine stress. Moreover, consistent trends and statistically significant correlations were detected between specific endogenous sugar parameters, such as the pre-stress end of day sucrose level in shoots, and physiological markers of atrazine tolerance. These significant relationships between endogenous carbohydrate metabolism and stress response therefore point to an important integration of carbon nutritional status and induction of stress tolerance in plants. The specific correlation between pre-stress sucrose level and greater atrazine tolerance may reflect adaptive mechanisms that link sucrose accumulation, photosynthesis-related stress and sucrose induction of stress defences.

Degradation of atrazine and isoproturon in surface and sub-surface soil materials undergoing different moisture and aeration conditions.

PubMed

Issa, Salah; Wood, Martin

2005-02-01

The influence of different moisture and aeration conditions on the degradation of atrazine and isoproturon was investigated in environmental samples aseptically collected from surface and sub-surface zones of agricultural land. The materials were maintained at two moisture contents corresponding to just above field capacity or 90% of field capacity. Another two groups of samples were adjusted with water to above field capacity, and, at zero time, exposed to drying-rewetting cycles. Atrazine was more persistent (t(1/2) = 22-35 days) than isoproturon (t(1/2) = 5-17 days) in samples maintained at constant moisture conditions. The rate of degradation for both herbicides was higher in samples maintained at a moisture content of 90% of field capacity than in samples with higher moisture contents. The reduction in moisture content in samples undergoing desiccation from above field capacity to much lower than field capacity enhanced the degradation of isoproturon (t(1/2) = 9-12 days) but reduced the rate of atrazine degradation (t(1/2) = 23-35 days). This demonstrates the variability between different micro-organisms in their susceptibility to desiccation. Under anaerobic conditions generated in anaerobic jars, atrazine degraded much more rapidly than isoproturon in materials taken from three soil profiles (0-250 cm depth). It is suggested that some specific micro-organisms are able to survive and degrade herbicide under severe conditions of desiccation. Copyright (c) 2005 Society of Chemical Industry.

A finite element code for electric motor design

NASA Technical Reports Server (NTRS)

Campbell, C. Warren

1994-01-01

FEMOT is a finite element program for solving the nonlinear magnetostatic problem. This version uses nonlinear, Newton first order elements. The code can be used for electric motor design and analysis. FEMOT can be embedded within an optimization code that will vary nodal coordinates to optimize the motor design. The output from FEMOT can be used to determine motor back EMF, torque, cogging, and magnet saturation. It will run on a PC and will be available to anyone who wants to use it.

Analysis and Simulation of Narrowband GPS Jamming Using Digital Excision Temporal Filtering.

DTIC Science & Technology

1994-12-01

the sequence of stored values from the P- code sampled at a 20 MHz rate. When correlated with a reference vector of the same length to simulate a GPS ...rate required for the GPS signals, (20 MHz sampling rate for the P- code signal), the personal computer (PC) used run the simulation could not perform...This subroutine is used to perform a fast FFT based 168 biased cross correlation . Written by Capt Gerry Falen, USAF, 16 AUG 94 % start of code

Effects of biochars and MWNTs on biodegradation behavior of atrazine by Acinetobacter lwoffii DNS32.

PubMed

Yang, Fan; Jiang, Qun; Zhu, Moran; Zhao, Lulu; Zhang, Ying

2017-01-15

Whether the biodegradation of atrazine by Acinetobacter lwoffii DNS32 can have a difference in the presence of two representative carbon materials (CMs), namely, biochars (BCs) and carbon nanotubes (CNTs) is explored, through investigating the influence of CMs on the biodegradation rate, the viability of bacteria and the expression of atrazine genes in aqueous medium. Multi-walled carbon nanotubes (MWNTs), biochars resulted from corn straws (C-BCs) and that made from banana peels (B-BCs) were chosen as the examples. Compared to the control in the absence of C-BCs, B-BCs and MWNTs, the biodegradation efficiencies decrease from 95.3%, 101.8% and 94.8% to 82.6%, 41.8% and 31.1% as the concentrations of these materials increase from 10 to 100mg/L, indicating that BCs have relatively lower toxicity on the biodegradation of atrazine than CNTs, which are agreement with the results of bacterial viability. Transmission electron microscope (TEM) images of Acinetobacter lwoffii DNS32 cells exposure to CMs at 50mg/L show that the cell membrane can be destroyed at different levels after being exposed to various CMs, suggesting that the damage to the cell membrane induced by CMs is a substantial factor leading to the inactivation of bacteria, further decreasing the degradation rate and efficiency of bacteria. The enhanced bacterial growth and the up-regulation of degradation genes can stimulate the degradation rate to pre-adsorbed atrazine on the CMs. This study suggests that biodegradation of atrazine associated with CMs may depend on the carbon composition, structure and CM concentrations. The innovation point of this report is to compare the effects of biochars and CNTs on the degradation rate and activity of Acinetobacter lwoffii DNS32 and may help to further understand the environment effects of CMs. Copyright © 2016 Elsevier B.V. All rights reserved.

Leaching of Br-, metolachlor, alachlor, atrazine, deethylatrazine and deisopropylatrazine in clayey vadoze zone: a field scale experiment in north-east Greece.

PubMed

Vryzas, Zisis; Papadakis, Emmanuel Nikolaos; Papadopoulou-Mourkidou, E

2012-04-15

An extensive four-year research program has been carried out to explore and acquire knowledge about the fundamental agricultural practices and processes affecting the mobility and bioavailability of pesticides in soils under semi-arid Mediterranean conditions. Pesticide leaching was studied under field conditions at five different depths using suction cups. Monitoring of metolachlor, alachlor, atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and bromide ions in soil water, as well as dye patterns made apparent the significant role of preferential flow to the mobility of the studied compounds. Irrespective to their adsorption capacities and degradation rates, atrazine, metolachlor and bromide ions were simultaneously detected to 160 cm depth. Following 40 mm irrigation, just after their application, both alachlor and atrazine were leached to 160 cm depth within 18 h, giving maximum concentrations of 211 and 199 μg L(-1), respectively. Metolachlor was also detected in all depth when its application was followed by a rainfall event (50 mm) two weeks after its application. The greatest concentrations of atrazine, alachlor and metolachlor in soil water were 1795, 1166 and 845 μg L(-1), respectively. The greatest concentrations of atrazine's degradation products (both DEA and DIA) appeared later in the season compared to the parent compound. Metolachlor exhibited the greatest persistence with concentrations up to 10 μg L(-1) appearing in soil water 18 months after its application. Brilliant blue application followed by 40 mm irrigation clearly depict multi-branching network of preferential flow paths allowing the fast flow of the dye down to 150 cm within 24 h. This network was created by soil cracks caused by shrinking of dry soils, earthworms and plant roots. Chromatographic flow of the stained soil solution was evident only in the upper 10-15 cm of soil. Copyright © 2012 Elsevier Ltd. All rights reserved.

Occurrence of pesticides in transboundary aquifers of North-eastern Greece.

PubMed

Vryzas, Zisis; Papadakis, Emmanuel N; Vassiliou, George; Papadopoulou-Mourkidou, Euphemia

2012-12-15

A five-year groundwater monitoring program undertaken in Evros (north-east Greece), showed a diversification in the levels of pesticide residues detected in adjacent transboundary aquifers. During the first two years 37 wells, including irrigation, drinking water and artesian wells were monitored while the next three years the survey was focused on the 11 most contaminated wells. The presence of pesticide residues was also monitored in the phreatic horizon (shallow groundwater) of four experimental boreholes drilled in the respective margins of four fields. Among the compounds found alachlor, metolachlor, atrazine, desethylatrazine (DEA), desisopropylatrazine (DIA) and caffeine were constantly detected. Pesticide concentrations were much lower (up to 1.54 μg/L) in the water of the monitored drinking water wells (deep groundwater aquifers) compared to those found in the phreatic horizon (experimental boreholes) of the respective areas (up to 5.20 μg/L). DEA to atrazine concentration ratios (DAR) determined for the phreatic horizon of the three boreholes and respective wells were lower than 1, indicating that preferential flow was the cause of the fast downward movement of atrazine to the phreatic horizon. In contrast the DAR for the fourth borehole and the adjacent well were greater than 1 indicating the absence of preferential flow of atrazine. Catabolic processes of the soil converted atrazine to DEA which is more mobile than atrazine itself through chromatographic (darcian) flow. This differential behavior of pesticides in adjacent aquifers (3 km) was further investigated by determining the apparent age of water in the two wells. The apparent age of the water present in the first aquifer was 21.7 years whereas the apparent age of that in the second aquifer was approximately 1.2 years. The faster replenishing rate of the latter is an indication that this aquifer is very vulnerable to contamination with pollutants present in the infiltrated soil water. Copyright © 2012 Elsevier B.V. All rights reserved.

Herbicides and herbicide degradates in shallow groundwater and the Cedar River near a municipal well field, Cedar Rapids, Iowa

USGS Publications Warehouse

Boyd, R.A.

2000-01-01

Water samples were collected near a Cedar Rapids, Iowa municipal well field from June 1998 to August 1998 and analyzed for selected triazine and acetanilide herbicides and degradates. The purpose of the study was to evaluate the occurrence of herbicides and herbicide degradates in the well field during a period following springtime application of herbicides to upstream cropland. The well field is in an alluvial aquifer adjacent to the Cedar River. Parent herbicide concentrations generally were greatest in June, and decreased in July and August. Atrazine was most frequently detected and occurred at the greatest concentrations; acetochlor, cyanazine and metolachlor also were detected, but at lesser concentrations than atrazine. Triazine degradate concentrations were relatively small (<0.50 ??g/l) and generally decreased from June to August. Although the rate of groundwater movement is relatively fast (approx. 1 m per day) in the alluvial aquifer near the Cedar River, deethylatrazine (DEA) to atrazine ratios in groundwater samples collected near the Cedar River indicate that atrazine and DEA probably are gradually transported into the alluvial aquifer from the Cedar River. Deisopropylatrazine (DIA) to DEA ratios in water samples indicate most DIA in the Cedar River and alluvial aquifer is produced by atrazine degradation, although some could be from cyanazine degradation. Acetanilide degradates were detected more frequently and at greater concentrations than their corresponding parent herbicides. Ethanesulfonic-acid (ESA) degradates comprised at least 80% of the total acetanilide-degradate concentrations in samples collected from the Cedar River and alluvial aquifer in June, July and August; oxanilic acid degradates comprised less than 20% of the total concentrations. ESA-degradate concentrations generally were smallest in June and greater in July and August. Acetanilide degradate concentrations in groundwater adjacent to the Cedar River indicate acetanilide degradates are transported into the alluvial aquifer in a manner similar to that indicated for atrazine and DEA. Copyright (C) 2000 Elsevier Science B.V.

Fast algal eco-toxicity assessment: Influence of light intensity and exposure time on Chlorella vulgaris inhibition by atrazine and DCMU.

PubMed

Camuel, Alexandre; Guieysse, Benoit; Alcántara, Cynthia; Béchet, Quentin

2017-06-01

In order to develop a rapid assay suitable for algal eco-toxicity assessments under conditions representative of natural ecosystems, this study evaluated the short-term (<1h) response of algae exposed to atrazine and DCMU using oxygen productivity measurements. When Chlorella vulgaris was exposed to these herbicides under 'standard' low light intensity (as prescribed by OECD201 guideline), the 20min-EC 50 values recorded via oxygen productivity (atrazine: 1.32±0.07μM; DCMU: 0.31±0.005μM) were similar the 96-h EC 50 recorded via algal growth (atrazine: 0.56μM; DCMU: 0.41μM), and within the range of values reported in the literature. 20min-EC50 values increased by factors of 3.0 and 2.1 for atrazine and DCMU, respectively, when light intensity increased from 60 to 1400μmolm -2 s -1 of photosynthetically active radiation, or PAR. Further investigation showed that exposure time significantly also impacted the sensitivity of C. vulgaris under high light intensity (>840μmolm -2 s -1 as PAR) as the EC 50 for atrazine and DCMU decreased by up to 6.2 and 2.1 folds, respectively, after 50min of exposure at a light irradiance of 1400μmolm -2 s -1 as PAR. This decrease was particularly marked at high light intensities and low algae concentrations and is explained by the herbicide disruption of the electron transfer chain triggering photo-inhibition at high light intensities. Eco-toxicity assessments aiming to understand the potential impact of toxic compounds on natural ecosystems should therefore be performed over sufficient exposure times (>20min for C. vulgaris) and under light intensities relevant to these ecosystems. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydrologic and land-use factors associated with herbicides and nitrate in near-surface aquifers

USGS Publications Warehouse

Burkart, Michael R.; Kolpin, Dana W.

1993-01-01

Selected herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) metabolites, and NO−3 were examined in near-surface unconsolidated and bedrock aquifers in the midcontinental USA to study the hydrogeologic, spatial, and seasonal distribution of these contaminants. Groundwater samples were collected from 303 wells during the spring and late summer of 1991. At least one herbicide or atrazine metabolite was detected in 24% of the samples collected for herbicide analysis (reporting limit 0.05 µg/L). No herbicide concentration exceeded the USEPA's maximum contaminant level (MCL) or health advisory level. The most frequently detected compound was the at razine metabolite deethylatrazine [2-amino-4-chloro-6-(isopropylamino)-s-triazine] followed by atrazine, deisopropylatrazine [2-amino-4-chloro-6-(ethylamino)-s-triazine], prometon (2,4-bis(isopropylamino)-6-methyoxy-s-triazine), metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1methylethyl)acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], metribuzin [4-amino-6-(tert-butyl)-3-methylthio-as-triazine-5(4H)-one], simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], and cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile]. Nitrite plus nitrate, as nitrogen (N), exceeding 3.0 mg/L (excess NO−3), was found in 29% of the samples, and 6% had −3exceeding the MCL of 10 mg/L. Ammonium as N was detected in excess of 0.01 mg/L in 78% of the samples. A nonlinear increase in the frequency of atrazine detection occurred with decreases in reporting limit. The frequency of atrazine residue detection (atrazine + deethylatrazine + deisopropylatrazine) was 25% greater than for atrazine alone. Herbicide detections and excess NO−3 were notably lacking in the eastern part of the study region where it was estimated that herbicide and fertilizer use were among the largest in the region. Prometon, the second most frequently detected herbicide, was associated with non-agricultural land use. Herbicide and excess NO−3 were more frequent in unconsolidated aquifers than in bedrock aquifers. Aquifer depth, as direct measurement of proximity to recharge sources, was inversely related to frequency of herbicide detection and excess NO−3.

April 2006 Status of Forces Survey of Active-Duty Members: Administration, Datasets, and Codebook

DTIC Science & Technology

2006-08-01

be gathered on a particular question. For example, AD080SP is a flag variable indicating when respondents had another reason for a physical injury...94. [94---] Collge credits since enlistment 510 COLCREDF* Top coding flag for COLCRED 1028 COLCREDR Rec COLCRED-Lvl col cred since enlisting 256...homew 507 COMPEDSK [92SK-] Use home PC/onlin dstnce ed 508 COMPSPEDSK [93SK-] Sp Use home PC onlin dstnce 509 COLCRED 94. [94---] Collge credits

Effect of meteorology and soil condition on metolachlor and atrazine volatilization over a 10 year period

USDA-ARS?s Scientific Manuscript database

A 10-year study was conducted to focus on the impact of soil and climatic factors governing herbicide volatilization from an agricultural field. For the first 5 years, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] and atrazine [6-chloro-N-ethyl-N’-(1-methyl...

THE EFFECTS OF ATRAZINE METABOLITES ON PUBERTY AND THYROID FUNCTION IN THE MALE WISTAR RAT

EPA Science Inventory

The Effects of Atrazine Metabolites on Puberty and Thyroid Function in the Male Wistar Rat. Stoker, T.E1., Guidici, D.L.2, Laws, S.C.2 and Cooper, R.L.2 Gamete and Early Embryo Biology Branch and 2 Endocrinology Branch, Reproductive Toxicology Division, National Health and Envir...

EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND ITS BIOLOGICAL METABOLITES IN MALE LONG EVANS RATS

EPA Science Inventory

TITLE: EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND ITS BIOLOGICAL METABOLITES IN MALE LONG EVANS RATS.
Rolondo R. Enoch2, Sara N. Greiner 1, Geri L. Youngblood 1, Christine C. Davis 1, and Suzanne E. Fenton 1
1 U.S. Environmental Protection Agency, ORD, ...

Gestational Atrazine Exposure: Effects on Male Reproductive Development and Metabolite Distribution in the Dam, Fetus, and Neonate

EPA Science Inventory

Few studies have investigated the long-term effects of atrazine (ATR)following in utero exposure. We evaluated the effects of gestational exposure of Sprague Dawley dams to ATR (0, 1, 5.20, or 100 mg/Kg-d) on the reproductive development of male offspring. We also quantified the...

EXPOSURE PARAMETERS NECESSARY FOR DELAYED PUBERTY AND MAMMARY GLAND DEVELOPMENT IN LONG-EVANS RATS EXPOSED IN UTERO TO ATRAZINE

EPA Science Inventory

Exposure Parameters Necessary For Delayed Puberty And Mammary Gland Development In Long-Evans Rats Exposed In Utero To Atrazine

Jennifer L. Rayner1, 2, Carmen Wood2, and Suzanne E. Fenton2

1 Department of Environmental Sciences and Engineering, School of Public Heal...

ATRAZINE DOES NOT INDUCE GASTROINTESTINAL DISCOMFORT (PICA) IN RATS AT DOSES THAT INCREASE ACTH ANDCORTICOSTERONE RELEASE AND CAUSE CONDITIONED TASTE AVERSION.

EPA Science Inventory

Previous work has shown that a single oral administration of atrazine (ATR), a chlorotriazine herbicide, induces dose-dependent increases in plasma adrenocorticotropic hormone (ACTH) and serum corticosterone (CORT), with a LOEL of 12.5mg/kg. The mechanism for these effects is unk...

Effects of prenatal exposure to a low dose atrazine metabolite mixture onpubertal timing and prostate development of male Long-Evans rats

EPA Science Inventory

Atrazine (ATR) is a chlorotriazine herbicide extensively used in the US and other countries. Studies examining the effects of adult or developmental ATR exposure on the mammary gland (MG) have used either the Sprague Dawley (SD) or Long-Evans (LE) rat, but no strain comparisons h...

IN UTERO EXPOSURE TO ATRAZINE INDUCES DELAYED PUBERTY OF LONG EVANS RATS: DAM-MEDIATED EFFECTS IN FEMALES

EPA Science Inventory

IN UTERO EXPOSURE TO ATRAZINE INDUCES DELAYED PUBERTY OF LONG EVANS RATS: DAM-MEDIATED EFFECTS IN FEMALES.

J L Rayner1 and S E Fenton2.

1 University of North Carolina at Chapel Hill, School of Public Health, Chapel Hill, NC, and 2 Reproductive Toxicology Divisio...

NONYLPHENOL AND ATRAZINE INDUCE INVERSE EFFECTS ON MAMMARY GLAND DEVELOPMENT IN FEMALE RATS EXPOSED IN UTERO

EPA Science Inventory

Nonylphenol and Atrazine Induce Inverse Effects on Mammary Gland Development in Female Rats Exposed In Utero.
HJ Moon1, SY Han1, CC Davis2, and SE Fenton2
1 Department of Toxicology, NITR, Korea FDA, 5Nokbun-Dong, Eunpyung-Gu, Seoul, Korea and 2 Reproductive Toxicology Divi...

THE EFFECTS OF ATRAZINE AND ITS METABOLITE DACT ON HYPOTHALAMIC-PITUITARY-ADRENAL AXIS ACTIVATION IN ADULT MALE WISTAR RATS

EPA Science Inventory

Previous work in our laboratory has shown that a single administration of atrazine (ATR), a chloro-s-triazine herbicide that is used extensively throughout the USA and world, is able to induce a dose-dependent increase in plasma ACTH, with maximal concentrations observed at 15 mi...

EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND IT'S BIOLOGICAL METABOLITES IN MALE LONG EVANS RATS

EPA Science Inventory

TITLE: EFFECTS FROM GESTATIONAL EXPOSURE TO A MIXTURE OF ATRAZINE AND ITS BIOLOGICAL METABOLITES IN MALE LONG EVANS RATS.
Rolondo R. Enoch2, Sara N. Greiner 1, Geri L. Youngblood 1, Christine C. Davis 1, and Suzanne E. Fenton 1
1 U.S. Environmental Protection Agency, ORD, ...

ALTERATION OF THE HYPOTHALAMIC-PITUITARY GONADAL (HPG) AXIS IN WISTAR MALE RATS FOLLOWING A PREPUBERTAL EXPOSURE TO THE CHLOROTRIAZINE HERBICIDE SIMAZINE

EPA Science Inventory

Chlorotriazine herbicides, such as atrazine and simazine (SIM), are used extensively in the U.S. each year and both parent compounds and metabolites are detected in ground water in areas of major usage. We found previously that atrazine suppresses serum luteinizing hormone and p...

Effects of an atrazine, metolachlor and fipronil mixture on Hyalella azteca (Saussure) in a modified backwater wetland.

PubMed

Lizotte, Richard E; Knight, Scott S; Shields, F Douglas; Bryant, Charles T

2009-12-01

We examined the toxicity mitigation efficiency of a hydrologically modified backwater wetland amended with a pesticide mixture of atrazine, metolachlor, and fipronil, using 96 h survival bioassays with Hyalella azteca. Significant H. azteca 96 h mortality occurred within the first 2 h of amendment at the upstream amendment site but not at any time at the downstream site. H. azteca survival varied spatially and temporally in conjunction with measured pesticide mixture concentrations. Hyalella azteca 96 h survival pesticide mixture effects concentrations ranges were 10.214–11.997, 5.822–6.658, 0.650–0.817, and 0.030–0.048 μg L−1 for atrazine, metolachlor, fipronil, and fipronil-sulfone, respectively.

Watershed regressions for pesticides (WARP) for predicting atrazine concentration in Corn Belt streams

USGS Publications Warehouse

Stone, Wesley W.; Gilliom, Robert J.

2011-01-01

The 95-percent prediction intervals are well within a factor of 10 above and below the predicted concentration statistic. WARP-CB model predictions were within a factor of 5 of the observed concentration statistic for over 90 percent of the model-development sites. The WARP-CB residuals and uncertainty are lower than those of the National WARP model for the same sites. The WARP-CB models provide improved predictions of the probability of exceeding a specified criterion or benchmark for Corn Belt streams draining watersheds with high atrazine use intensities; however, National WARP models should be used for Corn Belt streams where atrazine use intensities are less than 17 kg/km2 of watershed area.

[Prospective DRG coding : Improvement in cost-effectiveness and documentation quality of in-patient hospital care].

PubMed

Geuss, S; Jungmeister, A; Baumgart, A; Seelos, R; Ockert, S

2018-02-01

In prospective reimbursement schemes a diagnosis-related group (DRG) is assigned to each case according to all coded diagnoses and procedures. This process can be conducted retrospectively after (DC) or prospectively during the hospitalization (PC). The use of PC offers advantages in terms of cost-effectiveness and documentation quality without impairing patient safety. A retrospective analysis including all DRG records and billing data from 2012 to 2015 of a surgical department was carried out. The use of PC was introduced into the vascular surgery unit (VS) in September 2013, while the remaining surgical units (RS) stayed with DC. Analysis focused on differences between VS and RS before and after introduction of PC. Characteristics of cost-effectiveness were earnings (EBIT-DA), length of stay (LOS), the case mix index (CMI) and the productivity in relation to the DRG benchmark (productivity index, PI). The number of recorded diagnoses/procedures (ND/NP) was an indicator for documentation quality. A total of 1703 cases with VS and 27,679 cases with RS were analyzed. After introduction of PC the EBIT-DA per case increased in VS but not in RS (+3342 Swiss francs vs. +84, respectively, p < 0.001). The CMI increased slightly in both groups (+0.10 VS vs. +0.08 RS, p > 0.05) and the LOS was more reduced in VS than in RS (-0.36 days vs. -0.03 days, p > 0.005). The PI increased in VS but decreased in RS (+0.131 vs. -0.032, p < 0.001), ND increased more in VS (+1.29 VS vs. +0.26 RS, p < 0.001) and NP remained stable in both groups. The use of PC helps to significantly improve cost-effectiveness and documentation quality of in-patient hospital care, essentially by optimizing LOS and cost weight in relation to the DRG benchmark, i. e. increasing the PI. The increasing ND indicates an improvement in documentation quality.

Learning and Networking: Utilization of a Primary Care Listserv by Pharmacists

PubMed Central

Trinacty, Melanie; Farrell, Barbara; Schindel, Theresa J; Sunstrum, Lisa; Dolovich, Lisa; Kennie, Natalie; Russell, Grant; Waite, Nancy

2014-01-01

Background Expanding into new types of practice, such as family health teams, presents challenges for practising pharmacists. The Primary Care Pharmacy Specialty Network (PC-PSN) was established in 2007 to support collaboration among pharmacists working in primary care. The PC-PSN offers to its members a listserv (also referred to as an electronic mailing list) jointly hosted by the Canadian Society of Hospital Pharmacists and the Canadian Pharmacists Association. Objectives: To characterize PC-PSN membership and participation in the listserv and to examine how the listserv is used by analyzing questions posted, concerns raised, and issues discussed. Methods: Qualitative content analysis was used to examine 1 year of archived PC-PSN listserv posts from the year 2010. Two coders used NVivo software to classify the content of posts. Research team members reviewed and discussed the coding reports to confirm themes emerging from the data. Results: Overall, 129 people (52.9% of the 244 listserv members registered at the end of the calendar year) posted to the listserv during the study period. These participants worked in various practice settings, with over half residing in Ontario (68/129 [52.7%]). A total of 623 posts were coded. Agreement between coders, for a sample of posts from 10 users, was acceptable (kappa = 0.78). The listserv was used to share information on a diverse set of topics, to support decision-making and acquire solutions for complex problems, and as a forum for mentorship. Conclusions: The qualitative content analysis of the PC-PSN listserv posts for the year 2010 showed that the listserv was a medium for information-sharing and for providing and receiving support, through mentorship from colleagues. Apparent learning needs included effective question-posing skills and application of evidence to individual patients. PMID:25364016

Is Medical Student Choice of a Primary Care Residency Influenced by Debt?

PubMed Central

Kahn, Marc J.; Markert, Ronald J.; Lopez, Fred A.; Specter, Steven; Randall, Howard; Krane, N. Kevin

2006-01-01

Context The average medical student accumulates more than $120,000 in debt upon graduation. Objective The purpose of this study was to investigate whether medical student debt affects residency choice. Design This was a cross-sectional research study. Setting This study was a 5-year analysis of student debt and residency choice for 2001–2005 graduates from 3 US medical schools (n = 2022): Tulane University School of Medicine, New Orleans, Louisiana; University of South Florida College of Medicine, Tampa, Florida; and Louisiana State University School of Medicine in New Orleans. Main outcome measures Individual student data were collected from offices of financial aid for debt prior to and during medical school to determine total debt at graduation. Total debt (adjusted for inflation) was compared with residency match results coded according to specialties listed in the Graduate Medical Education Directory 2005–2006. Graduates were coded into either primary care (PC) or nonprimary care (NPC) specialty categories. Logistic regression for the choice of a PC residency was used with 4 predictors: (1) total debt, (2) medical school, (3) year of graduation, and (4) number of years of training required for a residency program. Results Mean total debt for the study population was $89,807 (SD = 54,925). Graduates entering PC did not have significantly less total debt than those entering NPC ($87,206 vs $91,430; P = .09). Further, total debt was not a predictor of a PC residency after adjusting for medical school, year of graduation, and years of training in residency (P = .64). Conclusion There is no association between PC residency choice and debt. We conclude that medical students make residency decisions on the basis of a complex set of factors. PMID:17415301

Projection of Patient Condition Code Distributions Based on Mechanism of Injury

DTIC Science & Technology

2003-01-01

The Medical Readiness and Strategic Plan (MRSP)1998-20041 requires that the military services develop a method for linking real world patient load...data with modern Patient Condition (PC) codes to enable planners to forecast medical workload and resource requirements. Determination of the likely...various levels of medical care. Medical planners and logisticians plan for medical contingencies based on anticipated patient streams, distributions of

Message Passing vs. Shared Address Space on a Cluster of SMPs

NASA Technical Reports Server (NTRS)

Shan, Hongzhang; Singh, Jaswinder Pal; Oliker, Leonid; Biswas, Rupak

2000-01-01

The convergence of scalable computer architectures using clusters of PCs (or PC-SMPs) with commodity networking has become an attractive platform for high end scientific computing. Currently, message-passing and shared address space (SAS) are the two leading programming paradigms for these systems. Message-passing has been standardized with MPI, and is the most common and mature programming approach. However message-passing code development can be extremely difficult, especially for irregular structured computations. SAS offers substantial ease of programming, but may suffer from performance limitations due to poor spatial locality, and high protocol overhead. In this paper, we compare the performance of and programming effort, required for six applications under both programming models on a 32 CPU PC-SMP cluster. Our application suite consists of codes that typically do not exhibit high efficiency under shared memory programming. due to their high communication to computation ratios and complex communication patterns. Results indicate that SAS can achieve about half the parallel efficiency of MPI for most of our applications: however, on certain classes of problems SAS performance is competitive with MPI. We also present new algorithms for improving the PC cluster performance of MPI collective operations.

Evaluation of the genotoxic activity of dicamba and atrazine herbicides in several Mexican and South American varieties of sweetcorn (Zea mays L.).

PubMed

Reynoso, M S; Alvarez, C M; De la Cruz, L; Escoto, M D; Sánchez, J J G

2015-12-11

Corn is a major crop and various herbicides are used to maximize its production, which include a dicamba-atrazine mixture. This has great advantages, but can also induce DNA damage. Genotoxic activity was assessed by comet assay following application of two concentrations of dicamba-atrazine: 1000-2000 and 2000-4000 ppm. Apical meristem leaf nuclei from 119 varieties of sweetcorn plants from Mexico and South America, and from five commercial sweetcorn hybrids were used. Each accession comprised two individuals per concentration and two controls. Significant genotoxic activity (P < 0.001) was observed following treatment with 1000-2000 and 2000-4000 ppm compared to the negative control. There was no difference in the genotoxic activity induced by both 1000-2000 and 2000-4000 ppm concentrations in plants from Mexico and South America (P > 0.05) except (P < 0.05) in the 2000-4000 ppm treated plants from Mexico and the 1000-2000 ppm treated plants from South America. Sweetcorn hybrids showed significant genetic damage (P < 0.01) at all concentrations compared to the negative controls. Thus, the dicamba-atrazine mixture caused genetic damage to corn plants, and it suggested that Mexican sweetcorn is more sensitive to dicamba-atrazine than the maize varieties from South America. Neither hybrid status nor the origin avoids DNA damage caused by Marvel. Thus, maize can be useful as a biomonitor of genetic damage induced by chemicals and to identify possible phenotypes based upon the amount of genetic damage induced by herbicides and selection of resistant genotypes.

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutions.

PubMed

Toledo-Jaldin, Helen Paola; Blanco-Flores, Alien; Sánchez-Mendieta, Víctor; Martín-Hernández, Osnieski

2017-08-30

Removal potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMA-Br) and benzyl octadecyl dimethyl ammonium (BODA) chloride considering the critical micellar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain). Raw materials were characterized by XRD and Fourier transform infrared spectroscopy (FTIR), SMZ and SMC were analyzed by FTIR. Results obtained from kinetic adsorption experiments shown that equilibrium time is less for materials modified with HDTMA (8 h) than materials with BODA (10 and 12 h). Materials modified with the largest chain surfactant (BODA) showed more resistance to atrazine masse transference. The chemisorption was presented in the adsorption mechanisms of atrazine and adsorbent materials. Based on the results of adsorption isotherms Langmuir isotherms showed the better correlation coefficients value. The q max is greater for materials modified with BODA (0.9232 and 4.2448 mg/g) than for materials modified with HDTMA (0.6731 and 3.9121 mg/g). Therefore, SMZ and SMC modified with the largest chain surfactant has more affinity for the pesticide. The removal process at high concentration of atrazine depends of the partition process but at lower concentration, it occurs not only by this process but also by absorption process.

Natural variation reveals relationships between pre-stress carbohydrate nutritional status and subsequent responses to xenobiotic and oxidative stress in Arabidopsis thaliana

PubMed Central

Ramel, Fanny; Sulmon, Cécile; Gouesbet, Gwenola; Couée, Ivan

2009-01-01

Background Soluble sugars are involved in responses to stress, and act as signalling molecules that activate specific or hormone cross-talk transduction pathways. Thus, exogenous sucrose treatment efficiently induces tolerance to the herbicide atrazine in Arabidopsis thaliana plantlets, at least partially through large-scale modifications of expression of stress-related genes. Methods Availability of sugars in planta for stress responses is likely to depend on complex dynamics of soluble sugar accumulation, sucrose–starch partition and organ allocation. The question of potential relationships between endogenous sugar levels and stress responses to atrazine treatment was investigated through analysis of natural genetic accessions of A. thaliana. Parallel quantitative and statistical analysis of biochemical parameters and of stress-sensitive physiological traits was carried out on a set of 11 accessions. Key Results Important natural variation was found between accessions of A. thaliana in pre-stress shoot endogenous sugar levels and responses of plantlets to subsequent atrazine stress. Moreover, consistent trends and statistically significant correlations were detected between specific endogenous sugar parameters, such as the pre-stress end of day sucrose level in shoots, and physiological markers of atrazine tolerance. Conclusions These significant relationships between endogenous carbohydrate metabolism and stress response therefore point to an important integration of carbon nutritional status and induction of stress tolerance in plants. The specific correlation between pre-stress sucrose level and greater atrazine tolerance may reflect adaptive mechanisms that link sucrose accumulation, photosynthesis-related stress and sucrose induction of stress defences. PMID:19789177

Leaching and degradation of corn and soybean pesticides in an Oxisol of the Brazilian Cerrados.

PubMed

Laabs, V; Amelung, W; Pinto, A; Altstaedt, A; Zech, W

2000-11-01

Pesticide pollution of ground and surface water is of growing concern in tropical countries. The objective of this pilot study was to evaluate the leaching potential of eight pesticides in a Brazilian Oxisol. In a field experiment near Cuiabá, Mato Grosso, atrazine, chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, metolachlor, monocrotofos, simazine, and trifluraline were applied onto a Typic Haplustox. Dissipation in the topsoil, mobility within the soil profile and leaching of pesticides were studied for a period of 28 days after application. The dissipation half-life of pesticides in the topsoil ranged from 0.9 to 14 d for trifluraline and metolachlor, respectively. Dissipation curves were described by exponential functions for polar pesticides (atrazine, metolachlor, monocrotofos, simazine) and bi-exponential ones for apolar substances (chlorpyrifos, lambda-cyhalothrin, endosulfane alpha, trifluraline). Atrazine, simazine and metolachlor were moderately leached beyond 15 cm soil depth, whereas all other compounds remained within the top 15 cm of the soil. In lysimeter percolates (at 35 cm soil depth), 0.8-2.0% of the applied amounts of atrazine, simazine, and metolachlor were measured within 28 days after application. Of the other compounds less than 0.03% of the applied amounts was detected in the soil water percolates. The relative contamination potentials of pesticides, according to the lysimeter study, were ranked as follows: metolachlor > atrazine = simazine > monocrotofos > endsulfane alpha > chlorpyrifos > trifluraline > lambda-cyhalothrin. This order of the pesticides was also achieved by ranking them according to their effective sorption coefficient Ke, which is the ratio of Koc to field-dissipation half-life.

Decadal-scale changes of pesticides in ground water of the United States, 1993-2003.

PubMed

Bexfield, Laura M

2008-01-01

Pesticide data for ground water sampled across the United States between 1993-1995 and 2001-2003 by the U.S. Geological Survey National Water-Quality Assessment Program were evaluated for trends in detection frequency and concentration. The data analysis evaluated samples collected from a total of 362 wells located in 12 local well networks characterizing shallow ground water in agricultural areas and six local well networks characterizing the drinking water resource in areas of variable land use. Each well network was sampled once during 1993-1995 and once during 2001-2003. The networks provide an overview of conditions across a wide range of hydrogeologic settings and in major agricultural areas that vary in dominant crop type and pesticide use. Of about 80 pesticide compounds analyzed, only six compounds were detected in ground water from at least 10 wells during both sampling events. These compounds were the triazine herbicides atrazine, simazine, and prometon; the acetanilide herbicide metolachlor; the urea herbicide tebuthiuron; and an atrazine degradate, deethylatrazine (DEA). Observed concentrations of these compounds generally were < 0.12 microg L(-1). At individual wells, changes in concentrations typically were < 0.02 microg L(-1). Data analysis incorporated adjustments for changes in laboratory recovery as assessed through laboratory spikes. In wells yielding detectable concentrations of atrazine, DEA, and prometon, concentrations were significantly lower (alpha = 0.1) in 2001-2003 than in 1993-1995, whereas detection frequency of these compounds did not change significantly. Trends in atrazine concentrations at shallow wells in agricultural areas were found to be consistent overall with recent atrazine use data.

Early Clinical Diagnosis of PC1/3 Deficiency in a Patient With a Novel Homozygous PCSK1 Splice-Site Mutation.

PubMed

Härter, Bettina; Fuchs, Irene; Müller, Thomas; Akbulut, Ulas Emre; Cakir, Murat; Janecke, Andreas R

2016-04-01

Autosomal recessive proprotein convertase 1/3 (PC1/3) deficiency, caused by mutations in the PCSK1 gene, is characterized by severe congenital malabsorptive diarrhea, early-onset obesity, and certain endocrine abnormalities. We suspected PC1/3 deficiency in a 4-month-old girl based on the presence of congenital diarrhea and polyuria. Sequencing the whole coding region and splice sites detected a novel homozygous PCSK1 splice-site mutation, c.544-2A>G, in the patient. The mutation resulted in the skipping of exon 5, the generation of a premature termination codon, and nonsense-mediated PCSK1 messenger ribonucleic acid decay, which was demonstrated in complementary DNA derived from fibroblasts.

Sorption and leaching potential of isoproturon and atrazine in low organic carbon soil of Pakistan under a wheat-maize rotation

USDA-ARS?s Scientific Manuscript database

Limited data are available on the sorption and leaching of pesticides in agricultural soils of Pakistan with low soil organic carbon (OC). Sorption potential of two widely used pesticides, isoproturon and atrazine, was determined using the batch equilibration method on soils from 0-35 cm, 35-70 and ...

Atrazine transport within a coastal zone in Southeastern Puerto Rico: a sensitivity analysis of an agricultural field model and riparian zone management model

USDA-ARS?s Scientific Manuscript database

Water quality models are used to predict effects of conservation practices to mitigate the transport of herbicides to water bodies. We used two models - the Agricultural Policy/Environmental eXtender (APEX) and the Riparian Ecosystem Management Model (REMM) to predict the movement of atrazine from ...

Bidirectional impact of atrazine-induced elvations in progesterone (P4) on the LH Surge in the ovariectomized (OVX), estradiol (E2)-primed rat

EPA Science Inventory

Multiple daily exposures to the herbicide atrazine (ATZ) have been reported to suppress the luteinizing hormone surge (LHS) in female rats. Exposure has also been found to elevate P4 concentrations, and an increase in P4 is known to have a different directional effect on LH depen...

The effects of prenatal exposure to atrazine on pubertal and postnatal reproductive indices in the female rat

EPA Science Inventory

Atrazine (ATR) is a commonly used herbicide that can exert negative reproductive effects in animals. We examined the effects of vehicle or ATR at 1, 5, 20 and 100 mg/kg/d, administered to Sprague-Dawley rats on gestational days 14-21, once daily or divided into two doses per day,...

Bidirectional impact of atrazine-induced elevations in progesterone (P4) on the LH surge in the ovariectomized, estradiol (E2)-primed rat

EPA Science Inventory

Multiple daily exposures to the herbicide atrazine (ATZ) have been reported to suppress the luteinizing hormone surge (LHS) in female rats. Exposure has also been found to elevate P4 concentrations, and an increase in P4 is known to have a different directional effect on LH depe...

Oxidative degradation of triazine- and sulfonylurea-based herbicides using Fe(VI): The case study of atrazine and iodosulfuron with kinetics and degradation products

EPA Science Inventory

The occurrence of common herbicides (Atrazine, ATZ and Iodosufuron, IDS), in waters presents potential risk to human and ecological health. The oxidative degradation of ATZ and IDS by ferrate(VI) (FeVIO42-, Fe(VI)) is studied at different pH levels where kinetically observed se...

EXPOSURE PARAMETERS FOR DELAYED PUBERTY AND MAMMARY GLAND DEVELOPMENT IN LONG-EVANS RATS EXPOSED IN UTERO TO ATRAZINE

EPA Science Inventory

Exposure Parameters For Delayed Puberty And Mammary Gland Development In Long-Evans Rats Exposed In Utero To Atrazine

Jennifer L. Rayner1 and Suzanne E. Fenton2

1 UNC-Chapel Hill, DESE, Chapel Hill, NC, and 2 RTD, USEPA, NHEERL/ORD, RTP,NC

Prenatal exposure ...

THE EFFECT OF ATRAZINE ON PUBERTY IN THE MALE WISTAR RATS: AN EVALUATION IN THE PROTOCOL FOR THE ASSESSMENT OF PUBERTAL DEVELOPMENT AND THYROID FUNCTION

EPA Science Inventory

Since atrazine (ATR), a chlorotriazine herbicide, has been shown previously to alter the secretion of luteinizing hormone (LH) and prolactin (PRL) through a direct effect on the central nervous system (CNS), we hypothesized that exposure to ATR in the EDSTAC male pubertal protoco...

Water quality parameters controlling the photodegradation of two herbicides in surface waters of the Columbia Basin, Washington.

PubMed

Furman, Olha S; Yu, Miao; Teel, Amy L; Watts, Richard J

2013-11-01

The water quality parameters nitrate-nitrogen, dissolved organic carbon, and suspended solids were correlated with photodegradation rates of the herbicides atrazine and 2,4-D in samples collected from four sites in the Columbia River Basin, Washington, USA. Surface water samples were collected in May, July, and October 2010 and analyzed for the water quality parameters. Photolysis rates for the two herbicides in the surface water samples were then evaluated under a xenon arc lamp. Photolysis rates of atrazine and 2,4-D were similar with rate constants averaging 0.025 h(-1) for atrazine and 0.039 h(-1) for 2,4-D. Based on multiple regression analysis, nitrate-nitrogen was the primary predictor of photolysis for both atrazine and 2,4-D, with dissolved organic carbon also a predictor for some sites. However, at sites where suspended solids concentrations were elevated, photolysis rates of the two herbicides were controlled by the suspended solids concentration. The results of this research provide a basis for evaluating and predicting herbicide photolysis rates in shallow surface waters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reductive dechlorination of atrazine catalyzed by metalloporphyrins.

PubMed

Nelkenbaum, Elza; Dror, Ishai; Berkowitz, Brian

2009-03-01

Atrazine (2-chloro-4-(ethylamine)-6-(isopropylamine)-s-triazine) is a widely used herbicide which is considered a persistent groundwater contaminant. Its selective transformation mediated by cobalt or nickel porphyrins was studied in aqueous solutions at room temperature and ambient pressure. Several metalloporphyrins were examined as catalysts for the reaction and all yielded the same reaction, transforming atrazine solely to the seldomly reported form 2,4-bis(ethylamine)-6-methyl-s-triazine. The reaction involves dechlorination and migration of a methyl group to yield a symmetric product. Nickel 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP) was activated by nanosized zero-valent iron (nZVI) while cobalt porphyrins (TMPyP, 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine-(TP(OH)P) and 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)tetrakis (benzenesulfonic acid)-(TBSP)) were activated by titanium(III) citrate as the electron donor. The effect of pH on atrazine transformation was demonstrated for the catalytic system of TP(OH)P-Co/Ti(III) citrate. Finally, a comparison of the reactivities of cobalt TMPyP and TP(OH)P was given and the differences discussed.

Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

USGS Publications Warehouse

Fairchild, James F.; Ruessler, Shane; Carlson, A. Ron

1998-01-01

This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.

Determination of atrazine in rainfall and surface water by enzyme immunoassay

USGS Publications Warehouse

Dankwardt, Andrea; Wüst, Susanne; Elling, Wolfram; Thurman, E. Michael; Hock, Bertold

1994-01-01

Rainwater and surface water from four sites in Germany (Bavaria and Lower Saxony) were analyzed for atrazine by enzyme immunoassay from June 1990 until October 1992. The limit of quantification of the immunoassay was 0.02 μg/L with a middle of the test at 0.2 μg/L. About 60 % of the samples contained measurable amounts of atrazine. Seasonal trends were observed, with the highest concentration in the summer months of up to 4 μg/L for rainwater and up to 15 μg/L for surface waters. The highest concentrations were found in agricultural areas, while in the investigated national parks up to 0.56 μg/L could be detected in rain water. This points to long-range atmospheric transport from agricultural areas to pristine national parks. Samples from forest stands usually showed higher atrazine concentrations than samples from open fields. Deposition rates of 10 – 50 μg/m2 · yr were observed in the national parks and 10–180 μg/m2 · yr at the agricultural sites. Comparison of results obtained by enzyme immunoassay and GC/MS showed a good correlation of r = 0.95.

Pharmaceuticals and endocrine disrupting compounds in U.S. drinking water.

PubMed

Benotti, Mark J; Trenholm, Rebecca A; Vanderford, Brett J; Holady, Janie C; Stanford, Benjamin D; Snyder, Shane A

2009-02-01

The drinking water for more than 28 million people was screened for a diverse group of pharmaceuticals, potential endocrine disrupting compounds (EDCs), and other unregulated organic contaminants. Source water, finished drinking water, and distribution system (tap) water from 19 U.S. water utilities was analyzed for 51 compounds between 2006 and 2007. The 11 most frequently detected compounds were atenolol, atrazine, carbamazepine, estrone, gemfibrozil, meprobamate, naproxen, phenytoin, sulfamethoxazole, TCEP, and trimethoprim. Median concentrations of these compounds were less than 10 ng/L, except for sulfamethoxazole in source water (12 ng/L), TCEP in source water (120 ng/L), and atrazine in source, finished, and distribution system water (32, 49, and 49 ng/L). Atrazine was detected in source waters far removed from agricultural application where wastewater was the only known source of organic contaminants. The occurrence of compounds in finished drinking water was controlled by the type of chemical oxidation (ozone or chlorine) used at each plant. At one drinking water treatment plant, summed monthly concentrations of the detected analytes in source and finished water are reported. Atenolol, atrazine, DEET, estrone, meprobamate, and trimethoprim can serve as indicator compounds representing potential contamination from other pharmaceuticals and EDCs and can gauge the efficacy of treatment processes.

Pesticides in surface water, bed sediment, and ground water adjacent to commercial cranberry bogs, Lac du Flambeau Reservation, Vilas County, Wisconsin

USGS Publications Warehouse

Saad, David A.

2005-01-01

In samples from the Trout River, which is used as a source of water to maintain lake levels in the Corn Lakes, the only pesticides detected were the non-targeted compounds atrazine and deethyl atrazine, indicating it was not a source of targeted compounds detected in the Corn Lakes. Only two pesticides (chlorpyrifos and metolachlor) were detected in bed-sediment samples collected from the lakes; chlorpyrifos from Little Trout Lake and metolachlor from the Corn Lakes. Four pesticides (the targeted compounds napropamide and norflurazon and the non-targeted compounds atrazine and deethyl atrazine) were detected in ground-water samples from two of four sampled monitor wells. The highest ground-water concentrations (up to 0.14 ?g/L napropamide and 0.56 ?g/L norflurazon) were measured in samples from the monitoring well located directly downgradient from the Corn Lakes and commercial cranberry operations. No pesticides were detected in samples from the reference well located upgradient from the Corn Lakes and cranberry operations. Further study is needed to identify additional pesticides as well as chronic effects on aquatic organisms to determine whether cranberry-related pesticides affect the lake ecosystems of the Lac du Flambeau Reservation.

Occurrence, distribution, loads, and yields of selected pesticides in the Little River basin, Kentucky, 2003-04

USGS Publications Warehouse

Crain, Angela S.

2006-01-01

Water resources in the Little River Basin are potentially vulnerable to applications of pesticides associated with both agricultural and nonagricultural activities, because much of the basin is characterized by karst topography. Concerns about water quality resulting from pesticide use in karst areas and lack of data on concentrations of pesticides in surface water led to further investigation of water quality in the Little River Basin, which includes about 600 square miles in Christian and Trigg Counties and a portion of Caldwell County in western Kentucky. Water samples were collected in streams in the Little River Basin, Kentucky during 2003-04 as part of a study conducted in cooperation with the Kentucky Department of Agriculture. The objectives of the study were to assess the occurrence and distribution of pesticides, to evaluate the spatial and seasonal variability of pesticides, and to evaluate loads and yields of selected pesticides in the basin. A total of 91 water samples was collected at 4 fixed-network sites from March through November 2003 and from February through November 2004. An additional 20 samples were collected at 5 synoptic-network sites within the same period. Twenty-four pesticides were detected of the 127 pesticides analyzed in the stream samples. Of the 24 detected pesticides, 15 were herbicides, 7 were insecticides, and 2 were fungicides. The most commonly detected pesticides-atrazine, simazine, metolachlor, and acetochlor-were those most heavily used on crops during the study. Atrazine and simazine were detected in 100 percent of all surface-water samples, and metolachlor and acetochlor were detected in more than 45 percent. The pesticide degradate, deethylatrazine, was detected in 100 percent of the samples. Only one nonagricultural herbicide, prometon, was detected in more than 50 percent of the samples. Diazinon, the most commonly detected insecticide, was found in 25 percent of all samples and was found at all sites except Casey Creek. Metalaxyl was the most commonly detected fungicide (14 percent); most detections were in samples from the Sinking Fork subbasin. Concentrations of herbicides were highest following application in the spring (March-May). In contrast, insecticides typically were present during the summer (June-August). The most commonly detected pesticides in the Little River Basin were found at low concentrations in streams year-round. Atrazine and simazine (row-crop herbicides) had the highest measured concentrations (22 and 6.1 micrograms per liter (?g/L), respectively) and were the most heavily applied herbicides in the basin. Metolachlor also was heavily applied in the basin, but measured concentrations did not exceed 0.32 ?g/L. The insecticide, Malathion, was only detected in 4 percent of the samples, although it was heavily applied in the basin during 2003-04. Most detections of pesticides were at low concentrations in relation to drinking-water standards and guidelines established for the protection of aquatic life. Only two pesticide compounds--atrazine and simazine--exceeded the U.S. Environmental Protection Agency (USEPA) standards for drinking water. Atrazine exceeded the USEPA's maximum contaminant level (MCL) 19 times in 111 detections; simazine exceeded the established MCL 2 times in 111 detections. These exceedences occurred in the spring. Concentrations of atrazine also exceeded the established aquatic-life criterion (1.8 ?g/L) in 32 samples collected from all sites. Concentrations of deethylatrazine, an herbicide-transformation compound, tended to follow the same monthly concentration pattern as its parent compound (atrazine), but concentrations of deethylatrazine were lower than those of atrazine. Atrazine may have been present in the soil much longer at these sites, which might have allowed microbial populations to transform atrazine into deethylatrazine. A statistical comparison of concentrations of selected pesticides among four fixed-network sites

Twostep-by-twostep PIRK-type PC methods with continuous output formulas

NASA Astrophysics Data System (ADS)

Cong, Nguyen Huu; Xuan, Le Ngoc

2008-11-01

This paper deals with parallel predictor-corrector (PC) iteration methods based on collocation Runge-Kutta (RK) corrector methods with continuous output formulas for solving nonstiff initial-value problems (IVPs) for systems of first-order differential equations. At nth step, the continuous output formulas are used not only for predicting the stage values in the PC iteration methods but also for calculating the step values at (n+2)th step. In this case, the integration processes can be proceeded twostep-by-twostep. The resulting twostep-by-twostep (TBT) parallel-iterated RK-type (PIRK-type) methods with continuous output formulas (twostep-by-twostep PIRKC methods or TBTPIRKC methods) give us a faster integration process. Fixed stepsize applications of these TBTPIRKC methods to a few widely-used test problems reveal that the new PC methods are much more efficient when compared with the well-known parallel-iterated RK methods (PIRK methods), parallel-iterated RK-type PC methods with continuous output formulas (PIRKC methods) and sequential explicit RK codes DOPRI5 and DOP853 available from the literature.

Population-based study of the association of variants in mismatch repair genes with prostate cancer risk and outcomes

PubMed Central

Langeberg, Wendy J.; Kwon, Erika M.; Koopmeiners, Joseph S.; Ostrander, Elaine A.; Stanford, Janet L.

2009-01-01

Background Mismatch repair (MMR) gene activity may be associated with prostate cancer (PC) risk and outcomes. This study evaluated whether single nucleotide polymorphisms (SNPs) in key MMR genes are related to PC outcomes. Methods Data from two population-based case-control studies of PC among Caucasian and African-American men residing in King County, Washington were combined for this analysis. Cases (n=1,458) were diagnosed with PC in 1993–96 or 2002–05 and identified via the Seattle-Puget Sound SEER cancer registry. Controls (n=1,351) were age-matched to cases and identified via random digit dialing. Logistic regression was used to assess the relationship between haplotype-tagging SNPs and PC risk and disease aggressiveness. Cox proportional hazards regression was used to assess the relationship between SNPs and PC recurrence and PC-specific death. Results Nineteen SNPs were evaluated in the key MMR genes: five in MLH1, 10 in MSH2, and 4 in PMS2. Among Caucasian men, one SNP in MLH1 (rs9852810) was associated with: overall PC risk (OR=1.21, 95% CI=1.02, 1.44; p=0.03), more aggressive PC (OR=1.49, 95% CI=1.15–1.91; p<0.01), and PC recurrence (HR=1.83, 95% CI=1.18, 2.86; p<0.01), but not PC-specific mortality. A non-synonymous coding SNP in MLH1, rs1799977 (I219V), was also found to be associated with more aggressive disease. These results did not remain significant after adjusting for multiple comparisons. Conclusion This population-based case-control study provides evidence for a possible association with a gene variant in MLH1 in relation to risk of overall PC, more aggressive disease, and PC recurrence, which warrants replication. PMID:20056646

Managed aquifer recharge as environmental tool risk mitigation linked to the presence of herbicides.

NASA Astrophysics Data System (ADS)

Di Roma, Antonella; Nieto Yàbar, Daniel; Pepi, Salvatore; Vaccaro, Carmela

2017-04-01

The pollution due to some herbicides which was used in flood plains and karst areas of various regions in the world is causing major problems in supplying drinking water from surface water bodies and aquifers. Pesticides and herbicides are widely used in agriculture, vineyards, industry and public hygiene. They are spread on soil surface, in air, into deep soil causing problems in surface water bodies and aquifers. In Italy the interest of presence of pesticides in water resources began around 1980 after episodes of drinking water contamination due to some herbicides and atrazine (ATR). After years away from the ban on the use of atrazine (use prohibition in the 90's), its degradation products are still present in groundwater of large areas of the plains of Nord Italy (Bottoni et al.,2013). Intensive use of triazines has become harmful for the local population that live in the Veneto-Friuli plain where the high gravels permeability of alluvial fans allowed to the widespread diffusion of triazines and related metabolites. The main mechanism of atrazine action in soil is microbial degradation, the kinetics of these products is closely connected with the availability of nitrates in the soil. The half-life of atrazine is 30-180 days but its disintegration is blocked by nitrates presence (Jones et al 1982). ATR is trapped in cohesive levels as peat and silty clay soils and periodically released by the interaction water sediment. Artificial recharge in areas with highly permeable aquifers allows to realize qualitative and quantitative regeneration because water low in nitrates and Dissolved Oxygen can promote the biological and chemical disintegration of pesticides such as atrazine and its metabolites. A case study is represented by the Friuli plain, near the Tagliamento river. Based on the WARBO project data that has applied artificial recharge in Mereto di Tomba test site where the dissolved nitrate content of water in some cases exceed the 50 mg/L limit according to Italian legislation (DL 152/2006), is proposed to apply this methodology to deal drinking water supply problem that afflicts the fields wells of Pordenone city resources. The study conducted on city aqueduct waters have shown the presence of atrazine metabolite that exceeds 0.10 µg/ l referred by law limits (ISPRA Report 2015). The release and infiltration of fresh water through the controlled charging reduces the concentration of nitrates promoting the degradation of atrazine metabolites. Application of recharging methods could be a method the contamination reduction of ATR and herbicides with the recovery of water resource. Bottoni P., Grenni P., Lucentini L., Barra Caracciolo A.2013.Terbuthylazine and other triazines in Italian water resources Microchemical Journal 107 136-142 Jones TW, Kemp WM, Stevenson JC, Means JC .1982. Degradation of atrazine in estuarine water/sediment systems and soils. J Environ Qual 11:632-638 www.isprambiente.gov.it/files/pubblicazioni/rapporti/rapporto-244/Rapporto_244_2016.pdf

Triazines mobility in sugarcane cultivated soils

NASA Astrophysics Data System (ADS)

Portocarrero, Rocio; Aparicio, Virginia; de Gerónimo, Eduardo; Costa, José Luis

2017-04-01

Atrazine and ametryn are pre and post-emergence herbicides, widely used in sugarcane crops in Argentina. Both herbicides are characterized by their moderate to high mobility in soil. The mobility increases with higher soil pH and lower organic matter content (OM). Tucuman province has the main sugarcane cultivated area in the country (>65%), which lies over a shallow aquifer and drains to the Salí river. Most of the cultivated soils from the southeast of the province have a pH> 7.3 and OM< 2.5%, therefore it is expected that atrazine and ametryn would have a high risk of mobility. The aim of this study was to estimate the leaching potential of atrazine and ametryn in soils from the southeast of Tucuman under sugarcane production. Miscible displacement experiments were carried out using undisturbed topsoil cores from four production fields, by triplicate. Each column was 15 cm length and 8 cm diameter. The dose of atrazine and ametryn that was applied in the columns corresponds to the equivalent dose used in the field of 2 kg ha-1a.i and 1.2 kg ha-1a.i respectively. Br- was used as a tracer molecule and it was applied previous to the herbicides pulse at a concentration of 150 BrK kg ha-1. Displacement was made with CaCl2 (0.01M) at a flow of 0.4 ml min-1, constant temperature (21°C) and unsaturated conditions (-0,5 m). The leached water samples were analyzed by ultra performance liquid chromatography (Waters® ACQUITY® UPLC) coupled to a mass spectrometer (MS/MSQuattro Premier XE Waters).The breakthrough curves (BTCs) for each compound were estimated by the convection-dispersion equation (using CXTFIT 2.0 program) in order to estimate the transport parameters. Results showed that the hydraulic transport was in equilibrium conditions, meaning that all the soil water is involved in solute convective transport. This could be explained by a soil porosity composed mainly by micro and mesopores, due to natural conditions or by tillage and harvest practices. Water velocity and dispersion range were 0.73-1.6 cm h-1 and 0.24-2.3 cm2 h-1 respectively. Atrazine had asymmetric BTCs, revealing chemical non-equilibrium conditions, with at least two adsorption-desorption sites participating in the process. Retardation coefficients were between 8-14 units. In contrast, ametryn concentrations in leached samples were low and inconsistent, so no BTCs could be described. Atrazine leaching potential was high in the studied soils. This herbicide is a well-known mobile molecule, found in many rural catchments and aquifers, independently of the soil type and the unsaturated properties or climatic conditions. On the contrary, ametryn had a higher potential to be sorbed and was less mobile than atrazine. This implies that there is a higher risk of contaminating groundwater with atrazine than with ametryn in the southeast soils of Tucuman.

An Architecture for Coexistence with Multiple Users in Frequency Hopping Cognitive Radio Networks

DTIC Science & Technology

2013-03-01

the base WARP system, a custom IP core written in VHDL , and the Virtex IV’s embedded PowerPC core with C code to implement the radio and hopset...shown in Appendix C as Figure C.2. All VHDL code necessary to implement this IP core is included in Appendix G. 69 Figure 3.19: FPGA bus structure...subsystem functionality. A total of 1,430 lines of VHDL code were implemented for this research. 1 library ieee; 2 use ieee.std logic 1164.all; 3 use

Cytochrome P450 genes from the aquatic midge Chironomus tentans: Atrazine-induced up-regulation of CtCYP6EX3 contributing to oxidative activation of chlorpyrifos

USDA-ARS?s Scientific Manuscript database

The open reading frames of 19 cytochrome P450 monooxygenase (CYP) genes were sequenced from Chironomus tentans, a commonly used freshwater invertebrate model. Functional analysis of CtCYP6EX3 confirmed its atrazine-induced oxidative activation for chlorpyrifos by using a nanoparticle-based RNA inter...

Data quality scoring system for microcosm and mesocosm studies used to derive a level of concern for atrazine.

PubMed

Giddings, Jeffrey M; Campana, David; Nair, Shyam; Brain, Richard

2018-04-16

The US Environmental Protection Agency (USEPA) has historically used different methods to derive an aquatic level of concern (LoC) for atrazine, though all have generally relied on an expanding set of mesocosm and microcosm ("cosm") studies for calibration. The database of results from ecological effects studies with atrazine in cosms now includes 108 data points from 39 studies and forms the basis for assessing atrazine's potential to impact aquatic plant communities. Inclusion of the appropriate cosm studies and accurate interpretation of each data point-delineated as binary scores of "effect" (effect score 1) or "no effect" (effect score 0) of a specific atrazine exposure profile on plant communities in a single study-is critical to USEPA's approach to determining the LoC. We reviewed the atrazine cosm studies in detail and carefully interpreted their results in terms of the binary effect scores. The cosm database includes a wide range of experimental systems and study designs, some of which are more relevant to natural plant communities than others. Moreover, the studies vary in the clarity and consistency of their results. We therefore evaluated each study against objective criteria for relevance and reliability to produce a weighting score that can be applied to the effect scores when calculating the LoC. This approach is useful because studies that are more relevant and reliable have greater influence on the LoC than studies with lower weighting scores. When the current iteration of USEPA's LoC approach, referred to as the plant assemblage toxicity index (PATI), was calibrated with the weighted cosm data set, the result was a 60-day LoC of 21.2 μg/L. Integr Environ Assess Manag 2018;00:000-000. © 2018 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC). © 2018 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Estimation of placental and lactational transfer and tissue distribution of atrazine and its main metabolites in rodent dams, fetuses, and neonates with physiologically based pharmacokinetic modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Zhoumeng; Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602; Fisher, Jeffrey W.

Atrazine (ATR) is a widely used chlorotriazine herbicide, a ubiquitous environmental contaminant, and a potential developmental toxicant. To quantitatively evaluate placental/lactational transfer and fetal/neonatal tissue dosimetry of ATR and its major metabolites, physiologically based pharmacokinetic models were developed for rat dams, fetuses and neonates. These models were calibrated using pharmacokinetic data from rat dams repeatedly exposed (oral gavage; 5 mg/kg) to ATR followed by model evaluation against other available rat data. Model simulations corresponded well to the majority of available experimental data and suggest that: (1) the fetus is exposed to both ATR and its major metabolite didealkylatrazine (DACT) atmore » levels similar to maternal plasma levels, (2) the neonate is exposed mostly to DACT at levels two-thirds lower than maternal plasma or fetal levels, while lactational exposure to ATR is minimal, and (3) gestational carryover of DACT greatly affects its neonatal dosimetry up until mid-lactation. To test the model's cross-species extrapolation capability, a pharmacokinetic study was conducted with pregnant C57BL/6 mice exposed (oral gavage; 5 mg/kg) to ATR from gestational day 12 to 18. By using mouse-specific parameters, the model predictions fitted well with the measured data, including placental ATR/DACT levels. However, fetal concentrations of DACT were overestimated by the model (10-fold). This overestimation suggests that only around 10% of the DACT that reaches the fetus is tissue-bound. These rodent models could be used in fetal/neonatal tissue dosimetry predictions to help design/interpret early life toxicity/pharmacokinetic studies with ATR and as a foundation for scaling to humans. - Highlights: • We developed PBPK models for atrazine in rat dams, fetuses, and neonates. • We conducted pharmacokinetic (PK) study with atrazine in pregnant mice. • Model predictions were in good agreement with experimental rat and mouse PK data. • The fetus is exposed to atrazine/its main metabolite at levels similar to the dam. • The nursing neonate is exposed primarily to atrazine's main metabolite DACT.« less

Optical Storage Technology Subgroup (FIMUG)

DTIC Science & Technology

1990-04-01

SECURITY CLASSICATON O NGRS PAG E NPAGE OMNo. 0704- 01 " I a REPORT SECUR - ,. ASSF o RiSTRICTIVE MARKINGS Unclasified oJU IS M’ 2a SECURITY C,.ASS...USERS 22a. NAME OF RESPONSIBLE INDIVIDUAL i22o TELEPHONE (include Area Code) 22c OFFICE SYMBOL (I 00 Form 1473, JUN 06 Previous e1t3onJ art obSo1te...Mdium May Change Shape of Optical Storage." PC Week. 1988 (21 Jun). "More Volume Buyers Turning Eyes Toward Optical-Storage Market." PC Week. 1988 (25 Jul

Four-Dimensional Screening Anti-Counterfeiting Pattern by Inkjet Printed Photonic Crystals.

PubMed

Hou, Jue; Zhang, Huacheng; Su, Bin; Li, Mingzhu; Yang, Qiang; Jiang, Lei; Song, Yanlin

2016-10-06

A four-dimensional screening anti-counterfeiting QR code composed of differently shaped photonic crystal (PC) dots has been fabricated that could display four images depending on different lighting conditions. By controlling the rheology of poly(dimethylsiloxane) (PDMS), three kinds of PC dots could be sequentially integrated into one pattern using the layer-by-layer printing strategy. The information can be encoded and stored in shapes and read out by the difference in optical properties. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Semifield testing of a bioremediation tool for atrazine-contaminated soils: evaluating the efficacy on soil and aquatic compartments.

PubMed

Chelinho, Sónia; Moreira-Santos, Matilde; Silva, Cátia; Costa, Catarina; Viana, Paula; Viegas, Cristina A; Fialho, Arsénio M; Ribeiro, Rui; Sousa, José Paulo

2012-07-01

The present study evaluated the bioremediation efficacy of a cleanup tool for atrazine-contaminated soils (Pseudomonas sp. ADP plus citrate [P. ADP + CIT]) at a semifield scale, combining chemical and ecotoxicological information. Three experiments representing worst-case scenarios of atrazine contamination for soil, surface water (due to runoff), and groundwater (due to leaching) were performed in laboratory simulators (100 × 40 × 20 cm). For each experiment, three treatments were set up: bioremediated, nonbioremediated, and a control. In the first, the soil was sprayed with 10 times the recommended dose (RD) for corn of Atrazerba and with P. ADP + CIT at day 0 and a similar amount of P. ADP at day 2. The nonbioremediated treatment consisted of soil spraying with 10 times the RD of Atrazerba (day 0). After 7 d of treatment, samples of soil (and eluates), runoff, and leachate were collected for ecotoxicological tests with plants (Avena sativa and Brassica napus) and microalgae (Pseudokirchneriella subcapitata) species. In the nonbioremediated soils, atrazine was very toxic to both plants, with more pronounced effects on plant growth than on seed emergence. The bioremediation tool annulled atrazine toxicity to A. sativa (86 and 100% efficacy, respectively, for seed emergence and plant growth). For B. napus, results point to incomplete bioremediation. For the microalgae, eluate and runoff samples from the nonbioremediated soils were extremely toxic; a slight toxicity was registered for leachates. After only 7 d, the ecotoxicological risk for the aquatic compartments seemed to be diminished with the application of P. ADP + CIT. In aqueous samples obtained from the bioremediated soils, the microalgal growth was similar to the control for runoff samples and slightly lower than control (by 11%) for eluates. Copyright © 2012 SETAC.

Chloroplast membrane alterations in triazine-resistant Amaranthus retroflexus biotypes

PubMed Central

Arntzen, Charles J.; Ditto, Cathy L.; Brewer, Philip E.

1979-01-01

The effectiveness of diuron, atrazine, procyazine, and cyanazine were compared in controlling growth of redroot pigweed (Amaranthus retroflexus L.) in hydroponic culture. A very marked differential inhibition response was observed for atrazine between resistant and susceptible biotypes. Procyazine and cyanazine exhibited less dramatic differential responses, whereas diuron was equally effective in controlling growth in both biotypes. Photosystem II activity of chloroplasts from both triazine-resistant and triazine-susceptible biotypes was inhibited by diuron but only the chloroplasts from triazine-susceptible biotypes were inhibited significantly by atrazine. The photochemical activity of chloroplasts from triazine-resistant biotypes was partially resistant to procyazine or cyanazine inhibition. The parallel lack of diuron differential effects, partial procyazine and cyanazine differential response, and very marked atrazine differential response in both whole plant and chloroplast assays indicates that the chloroplast is the site of selective herbicide tolerance in these triazine-resistant redroot pigweed biotypes. Photosystem II photochemical properties were characterized by analysis of chlorophyll fluorescence transients in the presence or absence of herbicides. Data with susceptible chloroplasts indicated that both diuron and atrazine inhibit electron flow very near the primary electron acceptor of photosystem II. Only diuron altered the fluorescence transient in resistant chloroplasts. In untreated preparations there were marked differences in the fast phases of the fluorescence increase in resistant vs. susceptible chloroplasts; these data are interpreted as showing that the resistant plastids have an alteration in the rate of reoxidation of the primary photosystem II electron acceptor. Electrophoretic analysis of chloroplast membrane proteins of the two biotypes showed small changes in the electrophoretic mobilities of two polypeptide species. The data provide evidence for the following herbicide resistance mechanism: genetically controlled modification of the herbicide target site. Images PMID:16592608

Atrazine sorption by hydroxy-interlayered clays and their organic complexes.

PubMed

Indraratne, Srimathie P; Farenhorst, Annemieke; Goh, Tee Boon

2008-01-01

This study examined the sorption of atrazine by hydroxy-Fe interlayered montmorillonite (FeMt) and its hydroquinone (FeMtHQ), citrate (FeMtCt) and catechol (FeMtCC) complexes as well as by hydroxy-Al interlayered montmorillonite (AlMt) and its hydroquinone (AlMtHQ) and citrate (AlMtCt) complexes. Found among the clays were sorption distribution coefficients (K(d)) ranging from 24 to 123 mL g(-1) and maximum sorption (M) ranging from 2.2 to 16.8 microg g(-1). Both K(d) and M decreased in the order of FeMtCC > FeMtHQ > AlMtHQ > (AlMt = FeMt) > (AlMtCt = FeMtCt). The pH was negatively correlated with both K(d) (r = -0.90, p < 0.001) and M (r = -0.81, p < 0.001). When interlayered clays were associated with humified material (FeMtCC, FeMtHQ, AlMtHQ), both K(d) (r > 0.96, p < 0.01) and M (r > 0.94, p < 0.01) were highly positively correlated with total organic C and alkali-soluble C. However, clays with non-humified organic compounds (FeMtCt and AlMtCt) sorbed less atrazine than clays without any organic C (FeMt and AlMt). This suggests that functional groups of Fe-OH and Al-OH in FeMt and AlMt reduced the available sorption sites for atrazine by making complexes with citrate ions while forming FeMtCt and AlMtCt. The atrazine was sorbed through the hydrophobic interactions with organic compound surfaces as well as through H-bonding and ionic bonding with clay-mineral surfaces.

Toxicity of atrazine- and glyphosate-based formulations on Caenorhabditis elegans.

PubMed

García-Espiñeira, María; Tejeda-Benitez, Lesly; Olivero-Verbel, Jesus

2018-07-30

Atrazine and Glyphosate are herbicides massively used in agriculture for crop protection. Upon application, they are available to the biota in different ecosystems. The aim of this research was to evaluate the toxicity of Glyphosate and Atrazine based formulations (GBF and ABF, respectively). Caenorhabditis elegans was exposed to different concentrations of each single formulation, and to the mixture. Lethality, locomotion, growth, and fertility were measured as endpoints. Effects on gene expression were monitored utilizing green fluorescence protein transgenic strains. ABF caused lethality of 12%, 15%, and 18% for 6, 60, and 600 μM, respectively, displaying a dose dependence trend. GBF produced lethality of 20%, 50%, and 100% at 0.01, 10, and 100 μM, respectively. Locomotion inhibition ranged from 21% to 89% at the lowest and maximum tested concentrations for Atrazine; whereas for Glyphosate, exposure to 10 μM inhibited 87%. Brood size was decreased by 67% and 93% after treatment to 0.06 and 6 μM Atrazine, respectively; and by 23% and 93% after exposure to 0.01 and 10 μM Glyphosate, respectively. There were no significant differences in growth. Changes in gene expression occurred in all genes, highlighting the expression of sod-1, sod-4, and gpx-4 that increased more than two-fold after exposure to 600 μM ABF and 10 μM GBF. The effects observed for the mixture of these formulations were additive for lethality, locomotion and fertility. In short, GBF, ABF, and their mixture induced several toxic responses related to oxidative stress on C. elegans. Copyright © 2018 Elsevier Inc. All rights reserved.

Removal of triazine-based pollutants from water by carbon nanotubes: Impact of dissolved organic matter (DOM) and solution chemistry.

PubMed

Engel, Maya; Chefetz, Benny

2016-12-01

Adsorption of organic pollutants by carbon nanotubes (CNTs) in the environment or removal of pollutants during water purification require deep understanding of the impacts of the presence of dissolved organic matter (DOM). DOM is an integral part of environmental systems and plays a key role affecting the behavior of organic pollutants. In this study, the effects of solution chemistry (pH and ionic strength) and the presence of DOM on the removal of atrazine and lamotrigine by single-walled CNTs (SWCNTs) was investigated. The solubility of atrazine slightly decreased (∼5%) in the presence of DOM, whereas that of lamotrigine was significantly enhanced (by up to ∼70%). Simultaneous introduction of DOM and pollutant resulted in suppression of removal of both atrazine and lamotrigine, which was attributed to DOM-pollutant competition or blockage of adsorption sites by DOM. However the decrease in removal of lamotrigine was also a result of its complexation with DOM. Pre-introduction of DOM significantly reduced pollutant adsorption by the SWCNTs, whereas introduction of DOM after the pollutant resulted in the release of adsorbed atrazine and lamotrigine from the SWCNTs. These data imply that DOM exhibits higher affinity for the adsorption sites than the triazine-based pollutants. In the absence of DOM atrazine was a more effective competitor than lamotrigine for adsorption sites in SWCNTs. However, competition between pollutants in the presence of DOM revealed lamotrigine as the better competitor. Our findings help unravel the complex DOM-organic pollutant-CNT system and will aid in CNT-implementation in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

A physiologically based pharmacokinetic model for atrazine and its main metabolites in the adult male C57BL/6 mouse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin Zhoumeng; Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602; Fisher, Jeffrey W.

Atrazine (ATR) is a chlorotriazine herbicide that is widely used and relatively persistent in the environment. In laboratory rodents, excessive exposure to ATR is detrimental to the reproductive, immune, and nervous systems. To better understand the toxicokinetics of ATR and to fill the need for a mouse model, a physiologically based pharmacokinetic (PBPK) model for ATR and its main chlorotriazine metabolites (Cl-TRIs) desethyl atrazine (DE), desisopropyl atrazine (DIP), and didealkyl atrazine (DACT) was developed for the adult male C57BL/6 mouse. Taking advantage of all relevant and recently made available mouse-specific data, a flow-limited PBPK model was constructed. The ATR andmore » DACT sub-models included blood, brain, liver, kidney, richly and slowly perfused tissue compartments, as well as plasma protein binding and red blood cell binding, whereas the DE and DIP sub-models were constructed as simple five-compartment models. The model adequately simulated plasma levels of ATR and Cl-TRIs and urinary dosimetry of Cl-TRIs at four single oral dose levels (250, 125, 25, and 5 mg/kg). Additionally, the model adequately described the dose dependency of brain and liver ATR and DACT concentrations. Cumulative urinary DACT amounts were accurately predicted across a wide dose range, suggesting the model's potential use for extrapolation to human exposures by performing reverse dosimetry. The model was validated using previously reported data for plasma ATR and DACT in mice and rats. Overall, besides being the first mouse PBPK model for ATR and its Cl-TRIs, this model, by analogy, provides insights into tissue dosimetry for rats. The model could be used in tissue dosimetry prediction and as an aid in the exposure assessment to this widely used herbicide.« less

Seasonality effects on pharmaceuticals and s-triazine herbicides in wastewater effluent and surface water from the Canadian side of the upper Detroit River.

PubMed

Hua, Wen Yi; Bennett, Erin R; Maio, Xui-Sheng; Metcalfe, Chris D; Letcher, Robert J

2006-09-01

The influence of seasonal changes in water conditions and parameters on several major pharmacologically active compounds (PhACs) and s-triazine herbicides was assessed in the wastewater and sewage treatment plant (WSTP) effluent as well as the downstream surface water from sites on the Canadian side of the upper Detroit River, between the Little River WSTP and near the water intake of a major drinking water treatment facility for the City of Windsor (ON, Canada). The assessed PhACs were of neutral (carbamazepine, cotinine, caffeine, cyclophosphamide, fluoxetine, norfluoxetine, pentoxifylline, and trimethoprim) and acidic (ibuprofen, bezafibrate, clofibric acid, diclofenac, fenoprofen, gemfibrozil, indomethacin, naproxen, and ketoprofen) varieties. The major assessed s-triazine herbicides were atrazine, simazine, propazine, prometon, ametryn, prometryn, and terbutryn. At sampling times from September 2002 to June 2003, 15 PhACs were detected in the WSTP effluent at concentrations ranging from 1.7 to 1244 ng/L. The PhAC concentrations decreased by as much 92 to 100% at the Little River/Detroit River confluence because of the river dilution effect, with further continual decreases at sites downstream from the WSTP. The only quantifiable s-triazine in WSTP effluent, atrazine, ranged from 6.7 to 200 ng/L and was higher in Detroit River surface waters than in WSTP effluent. Only carbamazepine, cotinine, and atrazine were detectable at the low-nanogram and subnanogram levels in surface waters near a drinking water intake site. Unlike the PhACs, atrazine in the Detroit River is not attributable to point sources, and it is heavily influenced by seasonal agricultural usage and runoff. Detroit River surface water concentrations of carbamazepine, cotinine, and atrazine may present a health concern to aquatic wildlife and to humans via the consumption of drinking water.

A longitudinal study of atrazine and 2,4-D exposure and oxidative stress markers among Iowa corn farmers

PubMed Central

Lerro, Catherine C.; Beane Freeman, Laura E.; Portengen, Lützen; Kang, Daehee; Lee, Kyoungho; Blair, Aaron; Lynch, Charles F.; Bakke, Berit; De Roos, Anneclaire J.; Vermeulen, Roel C.H.

2018-01-01

Reactive oxygen species, potentially formed through environmental exposures, can overwhelm an organism’s antioxidant capabilities resulting in oxidative stress. Long-term oxidative stress is linked with chronic diseases. Pesticide exposures have been shown to cause oxidative stress in vivo. We utilized a longitudinal study of corn farmers and non-farming controls in Iowa to examine the impact of exposure to the widely used herbicides atrazine and 2,4-dichlorophenoxyacetic acid (2,4-D) on markers of oxidative stress. 225 urine samples were collected during five agricultural time periods (pre-planting, planting, growing, harvest, off-season) for 30 farmers who applied pesticides occupationally and 10 controls who did not; all were non-smoking men ages 40–60. Atrazine mercapturate (atrazine metabolite), 2,4-D, and oxidative stress markers (malondialdehyde [MDA], 8-hydroxy-2′-deoxyguanosine [8-OHdG], and 8-isoprostaglandin-F2α [8-isoPGF]) were measured in urine. We calculated β estimates and 95% confidence intervals (95%CI) for each pesticide-oxidative stress marker combination using multivariate linear mixed-effect models for repeated measures. Farmers had higher urinary atrazine mercapturate and 2,4-D levels compared to controls. In regression models, after natural log transformation, 2,4-D was associated with elevated levels of 8-OHdG (β=0.066, 95%CI=0.008–0.124) and 8-isoPGF (β=0.088, 95%CI=0.004–0.172). 2,4-D may be associated with oxidative stress because of modest increases in 8-OHdG, a marker of oxidative DNA damage, and 8-isoPGF, a product of lipoprotein peroxidation, with recent 2,4-D exposure. Future studies should investigate the role of 2,4-D-induced oxidative stress in the pathogenesis of human diseases. PMID:28116766

Decadal-scale changes of pesticides in ground water of the United States, 1993-2003

USGS Publications Warehouse

Bexfield, L.M.

2008-01-01

Pesticide data for ground water sampled across the United States between 1993-1995 and 2001-2003 by the U.S. Geological Survey National Water-Quality Assessment Program were evaluated for trends in detection frequency and concentration. The data analysis evaluated samples collected from a total of 362 wells located in 12 local well networks characterizing shallow ground water in agricultural areas and six local well networks characterizing the drinking water resource in areas of variable land use. Each well network was sampled once during 1993-1995 and once during 2001-2003. The networks provide an overview of conditions across a wide range of hydrogeologic settings and in major agricultural areas that vary in dominant crop type and pesticide use. Of about 80 pesticide compounds analyzed, only six compounds were detected in ground water from at least 10 wells during both sampling events. These compounds were the triazine herbicides atrazine, simazine, and prometon; the acetanilide herbicide metolachlor; the urea herbicide tebuthiuron; and an atrazine degradate, deethylatrazine (DEA). Observed concentrations of these compounds generally were <0.12 ??g L-1. At individual wells, changes in concentrations typically were <0.02 ??g L-1. Data analysis incorporated adjustments for changes in laboratory recovery as assessed through laboratory spikes. In wells yielding detectable concentrations of atrazine, DEA, and prometon, concentrations were significantly lower (?? = 0.1) in 2001-2003 than in 1993-1995, whereas detection frequency of these compounds did not change significantly. Trends in atrazine concentrations at shallow wells in agricultural areas were found to be consistent overall with recent atrazine use data. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Agricultural chemicals in groundwater of the midwestern United States: Relations to land use

USGS Publications Warehouse

Kolpin, D.W.

1997-01-01

To determine the relations between land use and concentrations of selected agricultural chemicals (nitrate, atrazine residue [atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) + deethylatrazinc (2-amino-4-chloro-6-isopropylamino-s-triazine) + deisopropylatrazine (2-amino-4-chloro-6-ethylamino-s-triazine)], and alachlor residue [alachlor, [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] + alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid)] in groundwater, detailed land use information based on accurate measurements from aerial photographs for the 1991 growing season was obtained within a 2-km radius surrounding 100 wells completed in near-surface unconsolidated aquifers in the midwestern USA. The most significant land use factors to the agricultural chemicals examined were: nitrate (amount of irrigated crop production, positive relation), atrazine residue (amount of irrigated crop production, positive relation), and alachlor residue (amount of highly erodible land, inverse relation). The investigation of smaller buffer sizes (size of circular area around sampled wells) proved insightful for this study. Additional land use factors having significant relations to all three agricultural chemicals were identified using these smaller buffer radii. The most significant correlations (correlation maxima) generally occurred at ≤500-m for nitrate and ≥1000-m for atrazine residue and alachlor residue. An attempt to improve the statistical relations to land use by taking hydrologic considerations into account (removing land outside the estimated most probable recharge area from the statistical analysis) was not as successful as anticipated. Only 45% of the nitrate, 32% of the atrazine residue, and 20% of the alachlor residue correlations were improved by a consideration of the estimated most probable recharge area.

Nitrate and herbicide loading in two groundwater basins of Illinois' sinkhole plain

USGS Publications Warehouse

Panno, S.V.; Kelly, W.R.

2004-01-01

This investigation was designed to estimate the mass loading of nitrate (NO3-) and herbicides in spring water discharging from groundwater basins in an agriculturally dominated, mantled karst terrain. The loading was normalized to land use and NO3- and herbicide losses were compared to estimated losses in other agricultural areas of the Midwestern USA. Our study area consisted of two large karst springs that drain two adjoining groundwater basins (total area of 37.7 km2) in southwestern Illinois' sinkhole plain, USA. The springs and stream that they form were monitored for almost 2 years. Nitrate-nitrogen (NO3-N) concentrations at three monitoring sites were almost always above the background concentration (1.9 mg/l). NO3-N concentrations at the two springs ranged from 1.08 to 6.08 with a median concentration of 3.61 mg/l. Atrazine and alachlor concentrations ranged from <0.01 to 34 ??g/l and <0.01 to 0.98 ??g/l, respectively, with median concentrations of 0.48 and 0.12 ??g/l, respectively. Approximately 100,000 kg/yr of NO3-N, 39 kg/yr of atrazine, and 2.8 kg/yr of alachlor were discharged from the two springs. Slightly more than half of the discharged NO3- came from background sources and most of the remainder probably came from fertilizer. This represents a 21-31% loss of fertilizer N from the groundwater basins. The pesticide losses were 3.8-5.8% of the applied atrazine, and 0.05-0.08% of the applied alachlor. The loss of atrazine adsorbed to the suspended solid fraction was about 2 kg/yr, only about 5% of the total mass of atrazine discharged from the springs. ?? 2004 Elsevier B.V. All rights reserved.

Herbicide loading to shallow ground water beneath Nebraska's Management Systems Evaluation Area.

PubMed

Spalding, Roy F; Watts, Darrell G; Snow, Daniel D; Cassada, David A; Exner, Mary E; Schepers, James S

2003-01-01

Better management practices can counter deterioration of ground water quality. From 1991 through 1996 the influence of improved irrigation practices on ground water pesticide contamination was assessed at the Nebraska Management Systems Evaluation Area. Three 13.4-ha corn (Zea mays L.) fields were studied: a conventional furrow-irrigated field, a surge-irrigated field and a center pivot-irrigated field, and a center pivot-irrigated alfalfa (Medicago sativa L.) field. The corn fields received one identical banded application of Bicep (atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] + metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamidel) annually; the alfalfa field was untreated. Ground water samples were collected three times annually from 16 depths of 31 multilevel samplers. Six years of sample data indicated that a greater than 50% reduction in irrigation water on the corn management fields lowered average atrazine concentrations in the upper 1.5 m of the aquifer downgradient of the corn fields from approximately 5.5 to <0.5 microg L(-1). Increases in deethylatrazine (DEA; 2-chloro-4-amino-6-isopropylamino-s-triazine) to atrazine molar ratios indicated that reducing water applications enhanced microbial degradation of atrazine in soil zones. The occurrence of peak herbicide loading in ground water was unpredictable but usually was associated with heavy precipitation within days of herbicide application. Focused recharge of storm runoff that ponded in the surge-irrigated field drainage ditch, in the upgradient road ditch, and at the downgradient end of the conventionally irrigated field was a major mechanism for vertical transport. Sprinkler irrigation technology limited areas for focused recharge and promoted significantly more soil microbial degradation of atrazine than furrow irrigation techniques and, thereby, improved ground water quality.

Emergency medicine resident education in palliative care: a needs assessment.

PubMed

Lamba, Sangeeta; Pound, Amy; Rella, Joseph G; Compton, Scott

2012-05-01

Hospice and Palliative Medicine is a newly designated subspecialty of Emergency Medicine (EM). As yet, no well defined palliative care (PC) models for education or training exist. A needs assessment is the first step towards developing a curriculum. To characterize emergency physicians' (EP) perceived educational and formal training needs for PC related skills. All EM residents and faculty of one academic facility were asked to complete an anonymous needs-assessment survey. Participants were asked to rank statements related to attitudes about PC and rate their formal training and knowledge in 10 aspects of PC using a 5-point Likert-scale. EPs also ranked 4 learning modalities in order of preference and 12 PC educational topics in order of perceived importance in an EM curriculum. Ninety-three percent (42/45) of eligible participants completed the survey (28 residents, 14 faculty). Respondents agreed/strongly agreed that PC skills are an important competence for EM (88%, 37/42) and that they would "like to have more training/education in PC" (79%, 33/42). Respondents also disagreed/strongly disagreed with the statement that "PC consult is called when no more can be done for the patient" (90%, 38/42). Important PC topics identified were pain management, discussing code status, and management of dyspnea and other symptoms in terminal illness. Bedside teaching was listed as the preferred learning modality. EM residents reported minimal training in pain management (46%, 13/28), managing hospice patients (54%, 15/28), withdrawal/withholding life support (54%, 15/28), and managing the imminently dying (43%, 12/28). There was no consistent, significant improvement reported in any domain as training and experience progressed from PGY (postgraduate year) 1 to PGY 4 to attending physician. EPs view PC skills as important for EM practice and report that they are not yet adequately educated and trained in providing PC. Domains of particular interest and targeted areas for PC skills training for EPs may include managing hospice patients, withdrawal of life support, prognostication, and pain management.

Atrazine Resistance in Chenopodium album

PubMed Central

Bettini, Priscilla; McNally, Sheila; Sevignac, Mireille; Darmency, Henri; Gasquez, Jacques; Dron, Michel

1987-01-01

In Chenopodium album two different levels of atrazine resistance have been found according to following criteria: lethal dose and leaf fluorescence curve. The intermediate (I) phenotype is represented by a low level of resistance and a typical I fluorescence curve. It arose at high frequency, within one generation, after self-pollination of particular plants displaying a susceptible (S) phenotype. The resistance phenotype (Ri) has a high level of resistance and presents a typical resistant fluorescence curve. It appeared after self-pollination of chemically treated I plants. The I, Ri, and also R (resistant plants found in atrazine treated fields) phenotypes contain a serine to glycine mutation at amino acid position 264 in the chloroplast psbA gene product. The steady state level of the psbA gene transcript is not modified between S, I, Ri, and R phenotypes. Images Fig. 4 PMID:16665624

a Linux PC Cluster for Lattice QCD with Exact Chiral Symmetry

NASA Astrophysics Data System (ADS)

Chiu, Ting-Wai; Hsieh, Tung-Han; Huang, Chao-Hsi; Huang, Tsung-Ren

A computational system for lattice QCD with overlap Dirac quarks is described. The platform is a home-made Linux PC cluster, built with off-the-shelf components. At present the system constitutes of 64 nodes, with each node consisting of one Pentium 4 processor (1.6/2.0/2.5 GHz), one Gbyte of PC800/1066 RDRAM, one 40/80/120 Gbyte hard disk, and a network card. The computationally intensive parts of our program are written in SSE2 codes. The speed of our system is estimated to be 70 Gflops, and its price/performance ratio is better than $1.0/Mflops for 64-bit (double precision) computations in quenched QCD. We discuss how to optimize its hardware and software for computing propagators of overlap Dirac quarks.

Calculation of Weibull strength parameters, Batdorf flaw density constants and related statistical quantities using PC-CARES

NASA Technical Reports Server (NTRS)

Szatmary, Steven A.; Gyekenyesi, John P.; Nemeth, Noel N.

1990-01-01

This manual describes the operation and theory of the PC-CARES (Personal Computer-Ceramic Analysis and Reliability Evaluation of Structures) computer program for the IBM PC and compatibles running PC-DOS/MS-DOR OR IBM/MS-OS/2 (version 1.1 or higher) operating systems. The primary purpose of this code is to estimate Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities. Included in the manual is the description of the calculation of shape and scale parameters of the two-parameter Weibull distribution using the least-squares analysis and maximum likelihood methods for volume- and surface-flaw-induced fracture in ceramics with complete and censored samples. The methods for detecting outliers and for calculating the Kolmogorov-Smirnov and the Anderson-Darling goodness-of-fit statistics and 90 percent confidence bands about the Weibull line, as well as the techniques for calculating the Batdorf flaw-density constants are also described.

Fortran Program for X-Ray Photoelectron Spectroscopy Data Reformatting

NASA Technical Reports Server (NTRS)

Abel, Phillip B.

1989-01-01

A FORTRAN program has been written for use on an IBM PC/XT or AT or compatible microcomputer (personal computer, PC) that converts a column of ASCII-format numbers into a binary-format file suitable for interactive analysis on a Digital Equipment Corporation (DEC) computer running the VGS-5000 Enhanced Data Processing (EDP) software package. The incompatible floating-point number representations of the two computers were compared, and a subroutine was created to correctly store floating-point numbers on the IBM PC, which can be directly read by the DEC computer. Any file transfer protocol having provision for binary data can be used to transmit the resulting file from the PC to the DEC machine. The data file header required by the EDP programs for an x ray photoelectron spectrum is also written to the file. The user is prompted for the relevant experimental parameters, which are then properly coded into the format used internally by all of the VGS-5000 series EDP packages.

Biomarker analysis of American toad (Anaxyrus americanus) ...

EPA Pesticide Factsheets

The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environmental matrices throughout the United States. In surface waters, it has been found at concentrations from 0.04–2859 μg/L and thus presents a likely exposure scenario for non-target species such as amphibians. Studies have examined the effect of atrazine on the metamorphic parameters of amphibians, however, the data are often contradictory. Gosner stage 22–24 tadpoles were exposed to 0 (control), 10, 50, 250 or 1250 μg/L of atrazine for 48 h. Endogenous polar metabolites were extracted and analyzed using gas chromatography coupled with mass spectrometry. Statistical analyses of the acquired spectra with machine learning classification models demonstrated identifiable changes in the metabolomic profiles between exposed and control tadpoles. Support vector machine models with recursive feature elimination created a more efficient, non-parametric data analysis and increased interpretability of metabolomic profiles. Biochemical fluxes observed in the exposed groups of both A. americanus and H. versicolor displayed perturbations in a number of classes of biological macromolecules including fatty acids, amino acids, purine nucleosides, pyrimidines, and mono- and di-saccharides. Metabolomic

Reversible electrokinetic adsorption barriers for the removal of atrazine and oxyfluorfen from spiked soils.

PubMed

Vieira Dos Santos, E; Sáez, C; Cañizares, P; Martínez-Huitle, C A; Rodrigo, M A

2017-01-15

This study demonstrates the application of reversible electrokinetic adsorption barrier (REKAB) technology to soils spiked with low-solubility pollutants. A permeable reactive barrier (PRB) of granular activated carbon (GAC) was placed between the anode and cathode of an electrokinetic (EK) soil remediation bench-scale setup with the aim of enhancing the removal of two low-solubility herbicides (atrazine and oxyfluorfen) using a surfactant solution (sodium dodecyl sulfate) as the flushing fluid. This innovative study focused on evaluating the interaction between the EK system and the GAC-PRB, attempting to obtain insights into the primary mechanisms involved. The obtained results highlighted the successful treatment of atrazine and oxyfluorfen in contaminated soils. The results obtained from the tests after 15days of treatment were compared with those obtained using the more conventional electrokinetic soil flushing (EKSF) technology, and very important differences were observed. Although both technologies are efficient for removing the herbicides from soils, REKAB outperforms EKSF. After the 15-day treatment tests, only approximately 10% of atrazine and oxyfluorfen remained in the soil, and adsorption onto the GAC bed was an important removal mechanism (15-17% of herbicide retained). The evaporation loses in REKAB were lower than those obtained in EKSF (45-50% compared to 60-65%). Copyright © 2016 Elsevier B.V. All rights reserved.

Corn stover harvest increases herbicide movement to subsurface drains: RZWQM simulations

USGS Publications Warehouse

Shipitalo, Martin J.; Malone, Robert W.; Ma, Liwang; Nolan, Bernard T.; Kanwar, Rameshwar S.; Shaner, Dale L.; Pederson, Carl H.

2016-01-01

BACKGROUND Crop residue removal for bioenergy production can alter soil hydrologic properties and the movement of agrochemicals to subsurface drains. The Root Zone Water Quality Model (RZWQM), previously calibrated using measured flow and atrazine concentrations in drainage from a 0.4 ha chisel-tilled plot, was used to investigate effects of 50 and 100% corn (Zea mays L.) stover harvest and the accompanying reductions in soil crust hydraulic conductivity and total macroporosity on transport of atrazine, metolachlor, and metolachlor oxanilic acid (OXA). RESULTS The model accurately simulated field-measured metolachlor transport in drainage. A 3-yr simulation indicated that 50% residue removal decreased subsurface drainage by 31% and increased atrazine and metolachlor transport in drainage 4 to 5-fold when surface crust conductivity and macroporosity were reduced by 25%. Based on its measured sorption coefficient, ~ 2-fold reductions in OXA losses were simulated with residue removal. CONCLUSION RZWQM indicated that if corn stover harvest reduces crust conductivity and soil macroporosity, losses of atrazine and metolachlor in subsurface drainage will increase due to reduced sorption related to more water moving through fewer macropores. Losses of the metolachlor degradation product OXA will decrease due to the more rapid movement of the parent compound into the soil.

Effects of carbon nanotubes on atrazine biodegradation by Arthrobacter sp.

PubMed

Zhang, Chengdong; Li, Mingzhu; Xu, Xu; Liu, Na

2015-04-28

The environmental risks of engineered nanoparticles have attracted attention. However, little is known regarding the effects of carbon nanotubes (CNTs) on the biodegradation and persistence of organic contaminants in water. We investigated the impacts of pristine and oxidized multiwalled CNTs on the atrazine biodegradation rate and efficiency using Arthrobacter sp. At a concentration of 25mg/L, the CNTs enhanced the biodegradation rate by up to 20%; however, at a concentration of 100mg/L, the CNTs decreased the biodegradation rate by up to 50%. The stimulation effects resulted from enhanced bacterial growth and the overexpression of degradation genes. The inhibitory effects resulted from the toxicity of the CNTs at high concentrations. The differences between the two CNTs at tested concentrations were not significant. The biodegradation efficiency was not impacted by adsorption, and the pre-adsorbed atrazine on the CNTs was fully biodegraded when the CNT concentration was ≤25mg/L. This finding was consistent with the lack of observable desorption hysteresis for atrazine on the tested CNTs. Our results indicate that CNTs can enhance or inhibit biodegradation through a balance of two effects: the toxic effects on microbial activity and the effects of the changing bioavailability that result from adsorption and desorption. Copyright © 2015 Elsevier B.V. All rights reserved.

Hydroponic Uptake of Atrazine and Lambda-cyhalothrin in Aquatic Macrophytes

NASA Astrophysics Data System (ADS)

Bouldin, J. L.; Farris, J. L.; Moore, M. T.; Smith, S.; Cooper, C. M.

2005-05-01

Phytoremediation encompasses an array of plant-associated processes known to mitigate contaminants from soil, sediment, and water. Modification of pesticides associated with agricultural runoff includes processes directly associated with aquatic macrophytes in addition to soil geochemical modifications and associated rhizospheric degradation. Remediation attributes of two vegetative species common to agricultural drainages in the Mississippi Delta, USA, were assessed using atrazine and lambda-cyhalothrin. Concentrations used in 8-d hydroponic exposures were calculated using recommended field applications and a 5% runoff model from a 0.65-cm rainfall event on a 2.02-ha field. While greater atrazine uptake was measured in Juncus effusus, greater lambda-cyhalothrin uptake occurred in Ludwigia peploides. Maximum pesticide uptake was reached within 48 h for each exposure and subsequent translocation of pesticides to upper plant biomass occurred in macrophytes exposed to atrazine. Sequestration of 98.2% of lambda-cyhalothrin in roots of L. peploides was measured after 8 d. Translocation of lambda-cyhalothrin in J. effusus resulted in 25.4% of pesticide uptake partitioned to upper plant biomass. These individual macrophyte remediation studies measured species- and pesticide-specific uptake rates, indicating that the seasonality of pesticide applications and macrophyte emergence might interact strongly to enhance mitigation capabilities in edge-of-field conveyance structures.

Hydroponic uptake of atrazine and lambda-cyhalothrin in Juncus effusus and Ludwigia peploides.

PubMed

Bouldin, J L; Farris, J L; Moore, M T; Smith, S; Cooper, C M

2006-11-01

Phytoremediation encompasses an array of plant-associated processes known to mitigate contaminants from soil, sediment, and water. Modification of pesticides associated with agricultural runoff includes processes directly associated with aquatic macrophytes in addition to changes in soil geochemistry and associated rhizospheric degradation. Remediation attributes of two vegetative species common to agricultural drainages in the Mississippi Delta, USA, were assessed using atrazine and lambda-cyhalothrin. Concentrations used in 8-d hydroponic exposures were calculated using recommended field applications and a 5% runoff model from a 0.65-cm rainfall event on a 2.02-ha field. While greater atrazine uptake was measured in Juncus effusus, greater lambda-cyhalothrin uptake occurred in Ludwigia peploides. Maximum pesticide uptake was reached within 48h for each exposure and subsequent translocation of pesticides to upper plant biomass occurred in macrophytes exposed to atrazine. Sequestration of 98.2% of lambda-cyhalothrin in roots of L. peploides was measured after 8d. Translocation of lambda-cyhalothrin in J. effusus resulted in 25.4% of pesticide uptake partitioned to upper plant biomass. These individual macrophyte remediation studies measured species- and pesticide-specific uptake rates, indicating that seasonality of pesticide applications and macrophyte emergence might interact strongly to enhance mitigation capabilities in edge-of-field conveyance structures.

Steel Slag and Shredded Tires as Media for Blind Inlets to Improve Water Quality

NASA Astrophysics Data System (ADS)

Gonzalez, J. M.; Smith, D. R.; Livingston, S.

2015-12-01

Off-site transport of contaminants through surface runoff affects water quality. Blind inlets are proven conservation practices for reducing surface runoff, and consequently reducing nutrient loadings from small agricultural closed depressions to water bodies. Gravel is the most widely used blind inlet media to reduce flow, but not to sorb contaminants from the water. Readily available byproducts, such as steel slag and shredded tires, could be used as alternative media in blind inlets to sorb nutrients and pesticides from surface runoff. Sorption isotherms were performed to investigate the sorption capabilities of steel slag and shredded tires for phosphate and atrazine in electrolyte background solutions containing either 10 mM CaCl2 or KCl. Results of this research demonstrated that phosphate and atrazine were irreversibly sorbed by the steel slag and shredded tires. The steel slag increased the pH solution increased about 4 pH units after the sorption step; while the pH of the solution with shredded tires remained the same. Desorption of the phosphate and atrazine was low from the steel slag and shredded tires, respectively. Thus, the above results suggest that the steel slag and shredded tires can potentially be used as media to sorb phosphate and atrazine, respectively.

Short-term effects of benzalkonium chloride and atrazine on Elodea canadensis using a miniaturised microbioreactor system for an online monitoring of physiologic parameters.

PubMed

Vervliet-Scheebaum, Marco; Ritzenthaler, Raphael; Normann, Johannes; Wagner, Edgar

2008-02-01

The study evaluated the effects of benzalkonium chloride (BAC) and atrazine on the macrophyte Elodea canadensis (Michaux) using a miniaturised monitoring test system consisting of a microbioreactor of reduced volume and integrated sensors for the online measurement of physiologic parameters, like oxygen production and different parameters of fluorescence. Different concentrations of both chemicals were applied to leaves of E. canadensis and the physiologic endpoints evaluated after 1h. A concentration-dependent reduction of the oxygen production and of the effective quantum yield of energy conversion was recorded. The mini-PAM technique implemented in the presented system allowed for a clear monitoring of the kinetic of BAC and atrazine, showing their distinct mode of action. No observable adverse effects were recorded up to concentrations of 2.5 mg/L and 10 microg/L, for BAC and atrazine, respectively. These values are in accordance with available results in the literature, hence indicating that the microbioreactor test system might be suitable, on the one hand, for the laboratory screening of potential short-term toxicity of contaminants on aquatic plants, and on the other hand, serve as an in situ field biomonitoring system for the rapid detection of pollutants in water.

Comparison of fate and transport of isoxaflutole to atrazine and metolachlor in 10 Iowa rivers

USGS Publications Warehouse

Meyer, M.T.; Scribner, E.A.; Kalkhoff, S.J.

2007-01-01

Isoxaflutole (IXF), a newer low application rate herbicide, was introduced for weed control in corn (Zea mays) to use as an alternative to widely applied herbicides such as atrazine. The transport of IXF in streamwater has not been well-studied. The fate and transport of IXF and two of its degradation products was studied in 10 Iowa rivers during 2004. IXF rapidly degrades to the herbicidally active diketonitrile (DKN), which degrades to a biologically inactive benzoic acid (BA) analogue. IXF was detected in only four, DKN in 56, and BA in 43 of 75 samples. The concentrations of DKN and BA were approximately 2 orders of magnitude less than those of the commonly detected triazine and acetamide herbicides and their degradation products. Concentrations of IXF, DKN, and BA were highest during the May through June postplanting period. The concentration ratio of BA/DKN was similar to the deethylatrazine/atrazine ratio with smaller ratios occurring during May and June. The relative temporal variation of DKN and BA was similar to that observed for atrazine and deethylatrazine. This study shows that low application rate herbicides can have similar temporal transport patterns in streamwater as compared to more widely applied herbicides but at lower concentrations.

Los Alamos radiation transport code system on desktop computing platforms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briesmeister, J.F.; Brinkley, F.W.; Clark, B.A.

The Los Alamos Radiation Transport Code System (LARTCS) consists of state-of-the-art Monte Carlo and discrete ordinates transport codes and data libraries. These codes were originally developed many years ago and have undergone continual improvement. With a large initial effort and continued vigilance, the codes are easily portable from one type of hardware to another. The performance of scientific work-stations (SWS) has evolved to the point that such platforms can be used routinely to perform sophisticated radiation transport calculations. As the personal computer (PC) performance approaches that of the SWS, the hardware options for desk-top radiation transport calculations expands considerably. Themore » current status of the radiation transport codes within the LARTCS is described: MCNP, SABRINA, LAHET, ONEDANT, TWODANT, TWOHEX, and ONELD. Specifically, the authors discuss hardware systems on which the codes run and present code performance comparisons for various machines.« less

Pharmacy participation and claim characteristics in the Wisconsin Medicaid Pharmaceutical Care Program from 1996 to 2007.

PubMed

Look, Kevin A; Mott, David A; Leedham, Robert K; Kreling, David H; Hermansen-Kobulnicky, Carol J

2012-03-01

Under the 1995 Wisconsin Act 27, the biennial budget, Wisconsin Medicaid was required to develop an incentive-based pharmacy payment system for pharmaceutical care (PC) services. Started on July 1, 1996, the Wisconsin Medicaid Pharmaceutical Care Program (WMPCP) is the longest currently ongoing Medicaid program to compensate pharmacists for nondispensing services. The program reimburses pharmacies for providing PC services that increase patient compliance or prevent potential adverse drug problems by paying an enhanced PC dispensing fee. Pharmacists can bill for PC services provided to Wisconsin Medicaid fee-for-service and SeniorCare (i.e., state prescription drug assistance program for low-income seniors) beneficiaries. To examine trends in (a) the number of pharmacies participating in the WMPCP and the intensity of participation among participating pharmacies; and (b) frequencies of reason, action, result, and level-of-service (time) codes associated with PC service claims from July 1, 1996, through June 30, 2007, which represents Wisconsin state fiscal years (SFYs) 1997 through 2007. A retrospective, longitudinal, and descriptive research design was used to analyze all paid claims for PC services provided to Wisconsin Medicaid fee-for-service and SeniorCare recipients during SFYs 1997 through 2007. The total number of paid PC claims and the average number of claims paid per pharmacy were examined to determine trends in pharmacy participation. Mean annual reimbursement amounts for PC per claim and per pharmacy were calculated. Reason, action, result, and level-of-service (time) codes that appeared in the claims were grouped into categories and analyzed to characterize the total number of claims paid overall and per SFY. During the study period, one-half (n = 601) of the approximately 1,200 licensed pharmacies in the state of Wisconsin were paid for a claim through the WMPCP. However, intensity of participation in the WMPCP was low, with 57% of all participating pharmacies being paid for 10 or fewer PC claims and 19% paid for only 1 PC claim over the 11-year study period. The growth in claims per year coupled with smaller growth in the number of participating pharmacies resulted in a trend of growth in the mean number of claims per participating pharmacy in the program. The proportion of total WMPCP claims accounted for by the top 10 pharmacies with the highest volume of PC claims varied from 46.6% to 80.2% per year. Patient behaviors (e.g., early or late refills) and drug use issues/problems (e.g., patient complaints or symptoms) were the most common reasons for pharmacists to provide PC services (62% of all PC claims), although drug choice reasons (e.g., product selection opportunity) were more common after 2004. The majority (55.1%) of PC services took 15 minutes or less of pharmacists' time. The total dollar amount paid to pharmacies for PC services was $876,822 between SFYs 1997 and 2007, with an overall mean of $1,459 paid per participating pharmacy. Trends in pharmacy participation and claims volume showed growth, albeit limited, in PC program participation with a majority of paid claims dealing with patient behaviors and drug use issues or problems that consumed a small amount of pharmacists' time (15 minutes or less). The intensity of participation (claims per pharmacy) increased over time, suggesting that some pharmacies may have developed effective systems for participating and successfully submitting claims to WMPCP for enhanced dispensing fees. Further evaluation of the impact and implications of this program for patients, pharmacists, and the state is needed to gauge overall program success and provide evidence or guidance for continued or expanded PC initiatives.

Rhythmic complexity and predictive coding: a novel approach to modeling rhythm and meter perception in music

PubMed Central

Vuust, Peter; Witek, Maria A. G.

2014-01-01

Musical rhythm, consisting of apparently abstract intervals of accented temporal events, has a remarkable capacity to move our minds and bodies. How does the cognitive system enable our experiences of rhythmically complex music? In this paper, we describe some common forms of rhythmic complexity in music and propose the theory of predictive coding (PC) as a framework for understanding how rhythm and rhythmic complexity are processed in the brain. We also consider why we feel so compelled by rhythmic tension in music. First, we consider theories of rhythm and meter perception, which provide hierarchical and computational approaches to modeling. Second, we present the theory of PC, which posits a hierarchical organization of brain responses reflecting fundamental, survival-related mechanisms associated with predicting future events. According to this theory, perception and learning is manifested through the brain’s Bayesian minimization of the error between the input to the brain and the brain’s prior expectations. Third, we develop a PC model of musical rhythm, in which rhythm perception is conceptualized as an interaction between what is heard (“rhythm”) and the brain’s anticipatory structuring of music (“meter”). Finally, we review empirical studies of the neural and behavioral effects of syncopation, polyrhythm and groove, and propose how these studies can be seen as special cases of the PC theory. We argue that musical rhythm exploits the brain’s general principles of prediction and propose that pleasure and desire for sensorimotor synchronization from musical rhythm may be a result of such mechanisms. PMID:25324813

Atrazine and nitrate in drinking water and the risk of preterm delivery and low birth weight in four Midwestern states.

PubMed

Stayner, Leslie Thomas; Almberg, Kirsten; Jones, Rachael; Graber, Judith; Pedersen, Marie; Turyk, Mary

2017-01-01

Atrazine and nitrate are common contaminants in water, and there is limited evidence that they are associated with adverse birth outcomes. The objective of this study was to examine whether atrazine and nitrate in water are associated with an increased risk of preterm delivery (PTD) and term low birth weight (LBW). The study included a total of 134,258 singletons births born between January 1, 2004 and December 31, 2008 from 46 counties in four Midwestern states with public water systems that were included in the U.S. Environmental Protection Agency (EPA)'s atrazine monitoring program (AMP). Counties with a population of >300,000 were eliminated from the analyses in order to avoid confounding by urbanicity. Monthly child's sex, race and Hispanic ethnicity specific data were obtained from the states for estimating rates of PTD (<37 weeks) and very preterm (VPTD, <32 weeks), term LBW (<2.5kg among infants born at term) and very low birth weight (VLBW, <1.5kg). The rates were linked with county specific monthly estimates of the concentration of atrazine and nitrate in finished water. Multivariable negative binomial models were fitted to examine the association between the exposures and the adverse birth outcomes. Models were fitted with varying restrictions on the percentage of private well usage in the counties in order to limit the degree of exposure misclassification. Estimated water concentrations of atrazine (mean=0.42 ppb) and nitrate (mean=0.95ppm) were generally low. Neither contaminant was associated with an increased risk of term LBW. Atrazine exposure was associated with a significant increased rate of PTD when well use was restricted to 10% and the exposure was averaged over 4-6 months prior to birth (Rate Ratio for 1ppm increase [RR 1ppm ]=1.08, 95%CI=1.05,1.11) or over 9 months prior to birth (RR 1ppm =1.10, 95%CI=1.01,1.20). Atrazine exposure was also associated with an increased rate of VPTD when when well use was restricted to 10% and the exposure was averaged over 7-9 months prior to birth (RR 1ppm =1.19, 95%CI=1.04,1.36). Exposure to nitrate was significantly associated with an increased rate of VPTD (RR 1ppm =1.08, 95%CI=1.02,1.15) and VLBW (RR 1ppm =1.17, 95%CI=1.08,1.25) when well use was restricted to 20% and the exposure was averaged over 9 months prior to birth. The positive and negative findings from our study need to be interpreted cautiously given its ecologic design, and limitations in the data for the exposures and other risk factors. Nonetheless, our findings do raise concerns about the potential adverse effects of these common water contaminants on human development and health, and the adequacy of current regulatory standards. Further studies of these issues are needed with individual level outcome data and more refined estimates of exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Clinical implications of miRNAs in the pathogenesis, diagnosis and therapy of pancreatic cancer

PubMed Central

Rachagani, Satyanarayana; Macha, Muzafar A.; Heimann, Nicholas; Seshacharyulu, Parthasarathy; Haridas, Dhanya; Chugh, Seema; Batra, Surinder K.

2014-01-01

Despite considerable progress being made in understanding pancreatic cancer (PC) pathogenesis, it still remains the 10th most often diagnosed malignancy in the world and 4th leading cause of cancer related deaths in the United States with a five year survival rate of only 6%. The aggressive nature, lack of early diagnostic and prognostic markers, late clinical presentation, and limited efficacy of existing treatment regimens makes PC a lethal cancer with high mortality and poor prognosis. Therefore, novel reliable biomarkers and molecular targets are urgently needed to combat this deadly disease. MicroRNAs (miRNAs) are short (19–24 nucleotides) non-coding RNA molecules implicated in the regulation of gene expression at post-transcriptional level and play significant roles in various physiological and pathological conditions. Aberrant expression of miRNAs has been reported in several cancers including PC and is implicated in PC pathogenesis and progression, suggesting their utility in diagnosis, prognosis and therapy. In this review, we summarize the role of several miRNAs that regulate various oncogenes (KRAS) and tumor suppressor genes (p53, p16, SMAD4 etc) involved in PC development, their prospective roles as diagnostic and prognostic markers and their therapeutic targets. PMID:25453266

Liquid-liquid extraction assisted by a carbon nanoparticles interface. Electrophoretic determination of atrazine in environmental samples.

PubMed

Caballero-Díaz, Encarnación; Simonet, Bartolomé; Valcárcel, Miguel

2013-10-21

A novel method for the determination of atrazine, using liquid-liquid extraction assisted by a nanoparticles film formed in situ and composed of organic solvent stabilized-carbon nanoparticles, is described. The presence of nanoparticles located at the liquid-liquid interface reinforced the extraction of analyte from matrix prior to capillary electrophoresis (CE) analysis. Some influential experimental variables were optimized in order to enhance the extraction efficiency. The developed procedure confirmed that carbon nanoparticles, especially multi-walled carbon nanotubes, are suitable to be used in sample treatment processes introducing new mechanisms of interaction with the analyte. The application of the proposed preconcentration method followed by CE detection enabled the determination of atrazine in spiked river water providing acceptable RSD values (11.6%) and good recoveries (about 87.0-92.0%). Additionally, a similar extraction scheme was tested in soil matrices with a view to further applications in real soil samples.

Differential effects of herbicides atrazine and fenoxaprop-ethyl, and insecticides diazinon and malathion, on viability and maturation of porcine oocytes in vitro.

PubMed

Casas, Eduardo; Bonilla, Edmundo; Ducolomb, Yvonne; Betancourt, Miguel

2010-02-01

Exposure to pesticides may be a major cause of reproductive dysfunction in humans and animals. Atrazine and fenoxaprop-ethyl, widely used herbicides, and malathion and diazinon, organophosphate insecticides, are considered only slightly toxic to vertebrates; however, there is evidence of greater effects on reproductive function. The aim of this study was to evaluate the effect of these pesticides on oocyte viability and in vitro maturation. Gametes were matured in increasing concentrations of the pesticides and then stained with MTT to evaluate viability and bisbenzimide to assess the maturation stage, in the same oocyte. Atrazine had no effect on viability but maturation was significantly reduced, while fenoxaprop-ethyl affected both parameters. The insecticides affected viability and maturation but to a different degree. The four pesticides showed a more pronounced effect on maturation than on viability, due to a blockage at germinal vesicle stage.

Agricultural Compounds in Water and Birth Defects.

PubMed

Brender, Jean D; Weyer, Peter J

2016-06-01

Agricultural compounds have been detected in drinking water, some of which are teratogens in animal models. The most commonly detected agricultural compounds in drinking water include nitrate, atrazine, and desethylatrazine. Arsenic can also be an agricultural contaminant, although arsenic often originates from geologic sources. Nitrate has been the most studied agricultural compound in relation to prenatal exposure and birth defects. In several case-control studies published since 2000, women giving birth to babies with neural tube defects, oral clefts, and limb deficiencies were more likely than control mothers to be exposed to higher concentrations of drinking water nitrate during pregnancy. Higher concentrations of atrazine in drinking water have been associated with abdominal defects, gastroschisis, and other defects. Elevated arsenic in drinking water has also been associated with birth defects. Since these compounds often occur as mixtures, it is suggested that future research focus on the impact of mixtures, such as nitrate and atrazine, on birth defects.

The Response of Lemna minor to Mixtures of Pesticides That Are Commonly Used in Thailand.

PubMed

Tagun, Rungnapa; Boxall, Alistair B A

2018-04-01

In the field, aquatic organisms are exposed to multiple contaminants rather than to single compounds. It is therefore important to understand the toxic interactions of co-occurring substances in the environment. The aim of the study was to assess the effects of individual herbicides (atrazine, 2,4-D, alachlor and paraquat) that are commonly used in Thailand and their mixtures on Lemna minor. Plants were exposed to individual and binary mixtures for 7 days and the effects on plant growth rate were assesed based on frond area measurements. Experimental observations of mixture toxicity were compared with predictions based on single herbicide exposure data using concentration addition and independent action models. The single compound studies showed that paraquat and alachlor were most toxic to L. minor, followed by atrazine and then 2,4-D. For the mixtures, atrazine with 2,4-D appeared to act antagonistically, whereas alachlor and paraquat showed synergism.

Phytotoxicity of atrazine, isoproturon, and diuron to submersed macrophytes in outdoor mesocosms.

PubMed

Knauert, Stefanie; Singer, Heinz; Hollender, Juliane; Knauer, Katja

2010-01-01

The submersed macrophytes Elodea canadensis, Myriophyllum spicatum and Potamogeton lucens were constantly exposed over a five-week period to environmentally relevant concentrations of atrazine, isoproturon, diuron, and their mixture in outdoor mesocosms. Effects were evaluated investigating photosynthetic efficiency (PE) of the three macrophytes and growth of M. spicatum and E. canadensis. Adverse effects on PE were observed on days 2 and 5 after application. M. spicatum was found to be the more sensitive macrophyte. E. canadensis and P. lucens were less sensitive to atrazine, diuron and the mixture and insensitive to isoproturon. PE of M. spicatum was similarly affected by the single herbicides and the mixture demonstrating concentration addition. Growth of E. canadensis and M. spicatum was not reduced indicating that herbicide exposure did not impair plant development. Although PE measurements turned out to be a sensitive method to monitor PSII herbicides, plant growth remains the more relevant ecological endpoint in risk assessment.

Synergistic effects of a combined exposure to herbicides and an insecticide in Hyla versicolor

USGS Publications Warehouse

Mazanti, L.; Sparling, D.W.; Rice, C.; Bialek, K.; Stevenson, C.; Teels, B.; ,

2003-01-01

Combinations of the herbicides atrazine and metolachlor and the insecticide chlorpyrifos were tested under both laboratory and field conditions to determine their individual and combined effects on amphibian populations. In the lab Hyla versicolor tadpoles experienced 100% mortality when exposed to a high combination of the pesticides (2.0 mg/L atrazine, 2.54 mg/L metolachlor, 1.0 mg/L chlorpyrifos) whereas low concentrations of the pesticides (0.2 mg/L atrazine, 0.25 mg/L metolachlor, 0.1 mg/L chlorpyrifos) or high concentrations of either herbicides or insecticide alone caused lethargy, reduced growth and delayed metamorphosis but no significant mortality. In the field high herbicide, low insecticide and low herbicide, low insecticide mixtures significantly reduced amphibian populations compared to controls but in the low herbicide, low insecticide wetlands amphibian populations were able to recover through recruitment by the end of the season.

A low-cost PC-based telemetry data-reduction system

NASA Astrophysics Data System (ADS)

Simms, D. A.; Butterfield, C. P.

1990-04-01

The Solar Energy Research Institute's (SERI) Wind Research Branch is using Pulse Code Modulation (PCM) telemetry data-acquisition systems to study horizontal-axis wind turbines. PCM telemetry systems are used in test installations that require accurate multiple-channel measurements taken from a variety of different locations. SERI has found them ideal for use in tests requiring concurrent acquisition of data-reduction system to facilitate quick, in-the-field multiple-channel data analysis. Called the PC-PCM System, it consists of two basic components. First, AT-compatible hardware boards are used for decoding and combining PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for the DOS operating system was developed to simplify data-acquisition control and management. The software provides a quick, easy-to-use interface between the PC and PCM data streams. Called the Quick-Look Data Management Program, it is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. This paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data. Also discussed are problems and techniques associated with PC-based telemetry data acquisition, processing, and real-time display.

Place matters: A longitudinal analysis measuring the association between neighbourhood walkability and walking by age group and population center size in Canada.

PubMed

Wasfi, Rania; Steinmetz-Wood, Madeleine; Kestens, Yan

2017-01-01

This study examined the influence of walkability on walking behaviour and assessed whether associations varied according to life-stage and population center (PC) size. Walkability scores were obtained for the six-digit postal codes of residential neighbourhoods of 11,200 Canadians, who participated in biennial assessments of the National Population Health Survey from 1994 to 2010. Participants were stratified by age-group. Mixed-effects logistic regression models were used to estimate the influence of cumulative exposure to neighborhood walkability on utilitarian and exercise walking by PC size and life-stage. Associations of neighbourhood walkability with utilitarian and exercise walking varied according to age-group and PC size. Exposure to high walkable neighborhoods was associated with utilitarian walking in younger and older adults in all PC sizes, except for older adults living in a medium PC. Living in a highly walkable neighborhood in a large PC was associated with walking for exercise in younger (OR: 1.42; 95%CI: 1.20-1.67) and older adults (OR: 2.09; 95%CI: 1.51-2.89). Living in highly walkable neighbourhood in a medium PC was associated with walking for exercise in older adults (OR: 1.62; 95%CI: 1.15-2.29). These results emphasize the need to consider the size and nature of every community, and the age-group of a population when implementing strategies to promote walking.

Place matters: A longitudinal analysis measuring the association between neighbourhood walkability and walking by age group and population center size in Canada

PubMed Central

Steinmetz-Wood, Madeleine; Kestens, Yan

2017-01-01

This study examined the influence of walkability on walking behaviour and assessed whether associations varied according to life-stage and population center (PC) size. Walkability scores were obtained for the six-digit postal codes of residential neighbourhoods of 11,200 Canadians, who participated in biennial assessments of the National Population Health Survey from 1994 to 2010. Participants were stratified by age-group. Mixed-effects logistic regression models were used to estimate the influence of cumulative exposure to neighborhood walkability on utilitarian and exercise walking by PC size and life-stage. Associations of neighbourhood walkability with utilitarian and exercise walking varied according to age-group and PC size. Exposure to high walkable neighborhoods was associated with utilitarian walking in younger and older adults in all PC sizes, except for older adults living in a medium PC. Living in a highly walkable neighborhood in a large PC was associated with walking for exercise in younger (OR: 1.42; 95%CI: 1.20–1.67) and older adults (OR: 2.09; 95%CI: 1.51–2.89). Living in highly walkable neighbourhood in a medium PC was associated with walking for exercise in older adults (OR: 1.62; 95%CI: 1.15–2.29). These results emphasize the need to consider the size and nature of every community, and the age-group of a population when implementing strategies to promote walking. PMID:29261706

Program Processes Thermocouple Readings

NASA Technical Reports Server (NTRS)

Quave, Christine A.; Nail, William, III

1995-01-01

Digital Signal Processor for Thermocouples (DART) computer program implements precise and fast method of converting voltage to temperature for large-temperature-range thermocouple applications. Written using LabVIEW software. DART available only as object code for use on Macintosh II FX or higher-series computers running System 7.0 or later and IBM PC-series and compatible computers running Microsoft Windows 3.1. Macintosh version of DART (SSC-00032) requires LabVIEW 2.2.1 or 3.0 for execution. IBM PC version (SSC-00031) requires LabVIEW 3.0 for Windows 3.1. LabVIEW software product of National Instruments and not included with program.

Regenerable biocide delivery unit, volume 2

NASA Technical Reports Server (NTRS)

Atwater, James E.; Wheeler, Richard R., Jr.

1992-01-01

Source code for programs dealing with the following topics are presented: (1) life cycle test stand-parametric test stand control (in BASIC); (2) simultaneous aqueous iodine equilibria-true equilibrium (in C); (3) simultaneous aqueous iodine equilibria-pseudo-equilibrium (in C); (4) pseudo-(fast)-equilibrium with iodide initially present (in C); (5) solution of simultaneous iodine rate expressions (Mathematica); (6) 2nd order kinetics of I2-formic acid in humidity condensate (Mathematica); (7) prototype RMCV onboard microcontroller (CAMBASIC); (8) prototype RAM data dump to PC (in BASIC); and (9) prototype real time data transfer to PC (in BASIC).

TRAP/SEE Code Users Manual for Predicting Trapped Radiation Environments

NASA Technical Reports Server (NTRS)

Armstrong, T. W.; Colborn, B. L.

2000-01-01

TRAP/SEE is a PC-based computer code with a user-friendly interface which predicts the ionizing radiation exposure of spacecraft having orbits in the Earth's trapped radiation belts. The code incorporates the standard AP8 and AE8 trapped proton and electron models but also allows application of an improved database interpolation method. The code treats low-Earth as well as highly-elliptical Earth orbits, taking into account trajectory perturbations due to gravitational forces from the Moon and Sun, atmospheric drag, and solar radiation pressure. Orbit-average spectra, peak spectra per orbit, and instantaneous spectra at points along the orbit trajectory are calculated. Described in this report are the features, models, model limitations and uncertainties, input and output descriptions, and example calculations and applications for the TRAP/SEE code.

Pesticide concentrations in wetlands on the Lake Traverse Indian Reservation, South and North Dakota, July 2015

USGS Publications Warehouse

Carter, Janet M.; Thompson, Ryan F.

2016-05-04

During July 2015, water samples were collected from 18 wetlands on the Lake Traverse Indian Reservation in northeastern South Dakota and southeastern North Dakota and analyzed for physical properties and 54 pesticides. This study by the U.S. Geological Survey in cooperation with the Sisseton-Wahpeton Oyate was designed to provide an update on pesticide concentrations of the same 18 wetlands that were sampled for a reconnaissance-level assessment during July 2006. The purpose of this report is to present the results of the assessment of pesticide concentrations in selected Lake Traverse Indian Reservation wetlands during July 2015 and provide a comparison of pesticide concentrations between 2006 and 2015.Of the 54 pesticides that were analyzed for in the samples collected during July 2015, 47 pesticides were not detected in any samples. Seven pesticides—2-chloro-4-isopropylamino-6-amino-s-triazine (CIAT); 2,4–D; acetachlor; atrazine; glyphosate; metolachlor; and prometon—were detected in the 2015 samples with estimated concentrations or concentrations greater than the laboratory reporting level, and most pesticides were detected at low concentrations in only a few samples. Samples from all wetlands contained at least one detected pesticide. The maximum number of pesticides detected in a wetland sample was six, and the median number of pesticides detected was three.The most commonly detected pesticides in the 2015 samples were atrazine and the atrazine degradate CIAT (also known as deethylatrazine), which were detected in 14 and 13 of the wetlands sampled, respectively. Glyphosate was detected in samples from 11 wetlands, and metolachlor was detected in samples from 10 wetlands. The other detected pesticides were 2,4–D (4 wetlands), acetochlor (3 wetlands), and prometon (1 wetland).The same pesticides that were detected in the 2006 samples were detected in the 2015 samples, with the exception of simazine, which was detected only in one sample in 2006. Atrazine and CIAT were the most commonly detected pesticides in both sampling years; however, atrazine and CIAT were detected in fewer wetlands in 2015 (14 and 13 wetlands, respectively) than in 2006 (17 wetlands for both pesticides). The pesticides 2,4–D and prometon also were detected in fewer wetlands in 2015 than 2006, and simazine was only detected in 2006. In contrast, acetochlor, glyphosate, and metolachlor were detected in samples from more wetlands in 2015 than in 2006. In samples from individual wetlands, the number of pesticides detected was similar between 2006 and 2015. At least one pesticide was detected in all wetlands in 2015, and all but one wetland had pesticide detections in 2006.Concentrations of pesticides detected in samples from wetlands were compared to selected water-quality (human-health and aquatic-life) benchmarks. None of the concentrations in either 2006 or 2015 were greater than water-quality benchmarks, with the exception of atrazine. All detections of atrazine in the 2006 and 2015 samples were greater than the acute benchmark of 0.001 microgram per liter (μg/L) for vascular plants. In addition, some concentrations of 2,4–D and atrazine were within an order of magnitude of a water-quality benchmark. The 2,4–D concentrations in the 2015 samples from three wetlands were within an order of magnitude of the U.S. Environmental Protection Agency’s Maximum Contaminant Level of 70 μg/L (that is, sample concentrations were greater than 7.0 μg/L). The maximum dissolved atrazine concentration of 0.185 μg/L in the 2015 samples along with the concentrations in 2006 samples from two wetlands were within an order of magnitude of the acute benchmark of less than 1 μg/L for nonvascular plants (that is, concentrations were greater than 0.1 μg/L).

Methodes iteratives paralleles: Applications en neutronique et en mecanique des fluides

NASA Astrophysics Data System (ADS)

Qaddouri, Abdessamad

Dans cette these, le calcul parallele est applique successivement a la neutronique et a la mecanique des fluides. Dans chacune de ces deux applications, des methodes iteratives sont utilisees pour resoudre le systeme d'equations algebriques resultant de la discretisation des equations du probleme physique. Dans le probleme de neutronique, le calcul des matrices des probabilites de collision (PC) ainsi qu'un schema iteratif multigroupe utilisant une methode inverse de puissance sont parallelises. Dans le probleme de mecanique des fluides, un code d'elements finis utilisant un algorithme iteratif du type GMRES preconditionne est parallelise. Cette these est presentee sous forme de six articles suivis d'une conclusion. Les cinq premiers articles traitent des applications en neutronique, articles qui representent l'evolution de notre travail dans ce domaine. Cette evolution passe par un calcul parallele des matrices des PC et un algorithme multigroupe parallele teste sur un probleme unidimensionnel (article 1), puis par deux algorithmes paralleles l'un mutiregion l'autre multigroupe, testes sur des problemes bidimensionnels (articles 2--3). Ces deux premieres etapes sont suivies par l'application de deux techniques d'acceleration, le rebalancement neutronique et la minimisation du residu aux deux algorithmes paralleles (article 4). Finalement, on a mis en oeuvre l'algorithme multigroupe et le calcul parallele des matrices des PC sur un code de production DRAGON ou les tests sont plus realistes et peuvent etre tridimensionnels (article 5). Le sixieme article (article 6), consacre a l'application a la mecanique des fluides, traite la parallelisation d'un code d'elements finis FES ou le partitionneur de graphe METIS et la librairie PSPARSLIB sont utilises.

Occurrence of selected pesticides and their metabolites in near-surface aquifers of the midwestern United States

USGS Publications Warehouse

Kolpin, D.W.; Michael, Thurman E.; Goolsby, D.A.

1996-01-01

The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound. The metabolite alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid) was detected almost 10 times as frequently and at much higher concentrations than its parent compound alachlor (2-chloro-2‘,6‘-diethyl-N-(methoxymethyl)acetamide). The median detectable atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) concentration was almost half that of atrazine residue (atrazine plus the two atrazine metabolites analyzed). Cyanazine amide [2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-s-triazine] was detected almost twice as frequently as cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). Results show that information on pesticide metabolites is necessary to understand the environmental fate of pesticides. Consequently, if pesticide metabolites are not quantified, the effects of chemical use on groundwater quality would be substantially underestimated. Thus, continued research is needed to identify major degradation pathways for all pesticides and to develop analytical methods to determine their concentrations in water and other environmental media.

Acute and chronic toxicity of pesticides on tadpoles of Physalaemus cuvieri (Anura, Leptodactylidae).

PubMed

Wrubleswski, Juliana; Reichert, Francisco Wilson; Galon, Leandro; Hartmann, Paulo Afonso; Hartmann, Marilia Teresinha

2018-04-01

Brazil is the largest consumer of pesticides in the world. However, knowledge on how these pesticides affect wildlife is scarce. Among the vertebrates, amphibians are particularly important in research to assess the impact of pesticides because of the correlation between pesticide and the decline of these species. This study aimed to evaluate the acute and chronic toxicity of commercial formulations of pesticides, i.e., atrazine (herbicide), cypermethrin (insecticide), and tebuconazole (fungicide) in Physalaemus cuvieri tadpoles. Eggs were collected in nature and cultivated under controlled conditions in the laboratory. Toxicity tests were carried out under standard conditions to determine the lethal concentration (LC 50 ) after 96 h of exposure and to determine the effect of sublethal concentrations after 7 days. In addition, we performed swimming activity tests on tadpoles exposed to sublethal concentrations. The lethal concentration (LC 50 ) was 19.69 mg/L for atrazine, 0.24 mg/L for cypermethrin and 0.98 mg/L for tebuconazole. In the acute test, atrazine showed lower toxicity than cypermethrin and tebuconazole for P. cuvieri. Swimming activity was affected at sublethal doses of atrazine and cypermethrin, but was not after exposure to tebuconazole. Cypermethrin was the insecticide that most altered the swimming activity of the individuals tested. The risk evaluation analysis indicated risks for tadpoles exposed to three tested pesticides, specially cypermethrin.

Noncompetitive Homogeneous Detection of Small Molecules Using Synthetic Nanopeptamer-Based Luminescent Oxygen Channeling.

PubMed

Lassabe, Gabriel; Kramer, Karl; Hammock, Bruce D; González-Sapienza, Gualberto; González-Techera, Andrés

2018-05-15

Our group has previously developed immunoassays for noncompetitive detection of small molecules based on the use of phage borne anti-immunocomplex peptides. Recently, we substituted the phage particles by biotinylated synthetic anti-immunocomplex peptides complexed with streptavidin and named these constructs nanopeptamers. In this work, we report the results of combining AlphaLisa, a commercial luminescent oxygen channeling bead system, with nanopeptamers for the development of a noncompetitive homogeneous assay for the detection of small molecules. The signal generation of AlphaLisa assays relies on acceptor-donor bead proximity induced by the presence of the analyte (a macromolecule) simultaneously bound by antibodies immobilized on the surface of these beads. In the developed assay, termed as nanoAlphaLisa, bead proximity is sustained by the presence of a small model molecule (atrazine, MW = 215) using an antiatrazine antibody captured on the acceptor bead and an atrazine nanopeptamer on the donor bead. Atrazine is one of the most used pesticides worldwide, and its monitoring in water has relevant human health implications. NanoAlphaLisa allowed the homogeneous detection of atrazine down to 0.3 ng/mL in undiluted water samples in 1 h, which is 10-fold below the accepted limit in drinking water. NanoAlphaLisa has the intrinsic advantages for automation and high-throughput, simple, and fast homogeneous detection of target analytes that AlphaLisa assay provides.

Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue

USGS Publications Warehouse

Lerch, R.N.; Thurman, E.M.; Kruger, E.L.

1997-01-01

This study tested the hypothesis that sorption of hydroxylated atrazine degradation products (HADPs: hydroxyatrazine, HA; deethylhydroxyatrazine, DEHA; and deisopropylhydroxyatrazine, DIHA) to soils occurs by mixed-mode binding resulting from two simultaneous mechanisms: (1) cation exchange and (2) hydrophobic interaction. The objective was to use liquid chromatography and soil extraction experiments to show that mixed-mode binding is the mechanism controlling HADP sorption to soils and is also a mechanism for bound residue. Overall, HADP binding to solid-phase extraction (SPE) sorbents occurred in the order: cation exchange >> octadecyl (C18) >> cyanopropyl. Binding to cation exchange SPE and to a high-performance liquid chromatograph octyl (C8) column showed evidence for mixed-mode binding. Comparison of soil extracted by 0.5 M KH2P04, pH 7.5, or 25% aqueous CH3CN showed that, for HA and DIHA, cation exchange was a more important binding mechanism to soils than hydrophobic interaction. Based on differences between several extractants, the extent of HADP mixed-mode binding to soil occurred in the following order: HA > DIHA > DEHA. Mixed-mode extraction recovered 42.8% of bound atrazine residues from aged soil, and 88% of this fraction was identified as HADPs. Thus, a significant portion of bound atrazine residues in soils is sorbed by the mixed-mode binding mechanisms.

Herbicide and nitrate variation in alluvium underlying a cornfield at a site in Iowa County, Iowa

USGS Publications Warehouse

Kalkhoff, S.J.; Detroy, M.G.; Cherryholmes, K.; Kuzniar, R.L.

1992-01-01

A hydrologic investigation to determine vertical and seasonal variation of atrazine, alachlor, cyanazine, and nitrate at one location and to relate the variation to ground-water movement in the Iowa River alluvium was conducted in Iowa County, Iowa, from March 1986 to December 1987. Water samples were collected at discrete intervals through the alluvial sequence from the soil zone to the base of the aquifer. Alachlor, atrazine, and cyanazine were detected most frequently in the soil zone but also were present in the upper part of the alluvial aquifer. Alachlor was detected sporadically, whereas, atrazine, cyanazine, and nitrate were present throughout the year. In the alluvial aquifer, the herbicides generally were not detected during 1986 and were present in detectable concentrations for only a short period of time in the upper 1.6 meters of the aquifer during 1987. Nitrate was present throughout the alluvium and was stratified in the alluvial aquifer. The largest nitrate concentrations were detected in the middle part of the aquifer. Nitrate concentrations were variable only in the upper 2 meters of the aquifer. Vertical movement of herbicides and nitrate in the soil correlated with precipitation and degree of saturation. A clay layer retarded vertical movement of atrazine but not nitrate from the soil layer to the aquifer. Vertical movement could not account for the chemical variation in the alluvial aquifer.

Formation and transport of deethylatrazine and deisopropylatrazine in surface water

USGS Publications Warehouse

Thurman, E.M.; Meyer, M.T.; Mills, M.S.; Zimmerman, L.R.; Perry, C.A.; Goolsby, D.A.

1994-01-01

Field disappearance studies and a regional study of nine rivers in the Midwest Corn Belt show that deethylatrazine (DEA; 2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (DIA; 2-amino-4-chloro-6-ethylaminos-triazine) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 ??g/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations, giving a "second flush?? of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4 ?? 0.1 when atrazine is the major triazine present to 0.6 ?? 0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

Risk assessment for selected xenobiotics by bioassay methods with higher plants

NASA Astrophysics Data System (ADS)

Günther, Petra; Pestemer, Wilfried

1990-05-01

Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC50 values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips ( Brassica rapa var. rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress ( Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats ( Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC50 values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.

Pesticides in ground water in selected agricultural land-use areas and hydrogeologic settings in Pennsylvania, 2003-07

USGS Publications Warehouse

Loper, Connie A.; Breen, Kevin J.; Zimmerman, Tammy M.; Clune, John W.

2009-01-01

This report was prepared by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Agriculture (PDA) as part of the Pennsylvania Pesticides and Ground Water Strategy (PPGWS). Monitoring data and extensive quality-assurance data on the occurrence of pesticides in ground water during 2003–07 are presented and evaluated; decreases in the land area used for agriculture and corresponding changes in the use of pesticides also are documented. In the Pennsylvania ground waters assessed since 2003, concentrations of pesticides did not exceed any maximum contaminant or health advisory levels established by the U.S. Environmental Protection Agency; PPGWS actions are invoked by the PDA at fractions of these levels and were needed only in areas designated by the PDA for special ground-water protection. Previous investigations through 1998 of pesticides in Pennsylvania ground water identified land use, as a surrogate for pesticide use, and rock type of the aquifer combined with physiography as key hydrogeologic setting variables for understanding aquifer vulnerability to contamination and the common occurrence of atrazine and metolachlor in ground water. Of 20 major hydrogeologic settings in a framework established in 1999 for pesticide monitoring in Pennsylvania, 9 were identified as priorities for data collection in order to change the monitoring status from "inadequate" to "adequate" for the PPGWS. Agricultural and forested land-use areas are decreasing because of urban and suburban growth. In the nine hydrogeologic settings evaluated using 1992 and 2001 data, decreases of up to 12 percent for agricultural land and 10 percent for forested land corresponded to increases of up to 11 percent for urban land. Changes in agricultural pesticide use were computed from crop data. For example, from 1996 to 2004–05, atrazine use declined by about 15 percent to 1,314,000 lb/yr (pounds per year) and metolachlor use increased by about 20 percent to 895,000 lb/yr; these compounds are the two most-used agricultural pesticides statewide. In 2003–07, a baseline assessment of pesticides was conducted in five of nine hydrogeologic settings with inadequate monitoring data—the Blue Ridge crystalline and Triassic Lowland siliciclastic, Eastern Lake surficial, Devonian-Silurian carbonate, Great Valley siliciclastic, and Northeastern Glaciated surficial settings. Between 20 and 30 wells in each setting were monitored. Of the 126 wells sampled, 96 well-water samples were analyzed for at least 52 pesticide compounds at the USGS National Water Quality Laboratory (NWQL) using a method with a minimum reporting level (MRL) at or above 0.002 µg/L (micrograms per liter). Of the 96 well waters analyzed by NWQL, 43 had measureable concentrations of one or more pesticides. Atrazine and (or) deethylatrazine (CIAT), a degradation product of atrazine, were reported at or above the MRL in 39 of the 43 well waters. Neither atrazine nor CIAT were reported at concentrations exceeding 0.10 µg/L; all measured concentrations in these five settings were below PPGWS action levels. Metolachlor was present in 7 of the 43 well waters with measureable concentrations of 1 or more pesticides; however, concentrations were below the MRL. The other 30 samples (10 of 20 wells in the Blue Ridge crystalline and Triassic Lowland siliciclastic setting and all 20 wells in the Eastern Lake surficial setting) were analyzed for at least 19 pesticide compounds at the Pennsylvania Department of Environmental Protection Laboratory (PADEPL); the PADEPL reported no concentrations of pesticides at or above an MRL of 0.10 µg/L. Statistical tests using the NWQL analytical results showed correlations between pesticide occurrence and two indicators of water-quality degradation—the occurrence of total coliform bacteria and nitrate concentration. A 2 × 2 contingency-table test indicated a relation between presence or absence of atrazine or metolachlor and presence or absence of bacteria only for the 10 wells representing the Blue Ridge crystalline and Triassic Lowland siliciclastic setting. Results of Spearman’s rank test showed strong positive correlations in the Devonian-Silurian carbonate setting between 1) the number of pesticides above the MRLs and nitrate concentration, and 2) concentrations of atrazine and nitrate. Atrazine concentration and nitrate concentration also showed a statistically significant positive correlation in the Great Valley siliciclastic setting. An additional component of baseline monitoring was to evaluate changes in pesticide concentration in water from wells representing hydrogeologic settings most vulnerable to contamination from pesticides. In 2003, 16 wells originally sampled in the 1990s were resampled—4 each in the Appalachian Mountain carbonate, Triassic Lowland siliciclastic, Great Valley carbonate, and Piedmont carbonate settings. Nine of these wells, where pesticide concentrations from 1993 and 2003 were analyzed at the NWQL, were chosen for a paired-sample analysis using concentrations of atrazine and metolachlor. A statistically significant decrease in atrazine concentration was identified using the Wilcoxon signed-rank test (p = 0.004); significant temporal changes in metolachlor concentrations were not observed (p = 0.625). Monitoring in three areas of special ground-water protection, where selected pesticide concentrations in well water were at or above the PPGWS action levels, was done at wells BE 1370 (Berks County, Oley Township), BA 437 (Blair County, North Woodbury Township), and LN 1842 (Lancaster County, Earl Township). Co-occurrence of pesticide-degradation products with parent compounds was documented for the first time in ground-water samples collected from these three wells. Degradation products of atrazine, cyanazine, acetochlor, alachlor, and metolachlor were commonly at larger concentrations than the parent compound in the same water sample. Pesticide occurrence in water from wells neighboring the hot-spot wells was highly variable; however, the same sets of pesticide compounds that were present in wells BA 437, BE 1370, and LN 1842 were present to some degree in water from neighboring wells. To evaluate temporal changes in concentration, nonparametric statistical tests were used to determine overall and seasonal monotonic trends. Concentrations of alachlor, atrazine, metolachlor, and nitrate were examined using the 5-year (2003–07) and the long-term data from wells BA 437 and LN 1842 (1996–2007 and 1995–2007, respectively), and the long-term data for well BE 1370 (1998–2007); results showed either downward trends or no trends. Trends in acetochlor concentrations were tested only at well LN 1842 using the 5-year data; no trends were observed. Homogeneity of trend tests indicated statistically significant downward concentration trends in the long-term data were due to seasonal trends as follows: BA 437—alachlor and atrazine (summer); BE 1370—atrazine and metolachlor (winter) and alachlor (winter and spring); LN 1842—alachlor (summer and fall) and atrazine (spring and fall).

A PC-based telemetry system for acquiring and reducing data from multiple PCM streams

NASA Astrophysics Data System (ADS)

Simms, D. A.; Butterfield, C. P.

1991-07-01

The Solar Energy Research Institute's (SERI) Wind Research Program is using Pulse Code Modulation (PCM) Telemetry Data-Acquisition Systems to study horizontal-axis wind turbines. Many PCM systems are combined for use in test installations that require accurate measurements from a variety of different locations. SERI has found them ideal for data-acquisition from multiple wind turbines and meteorological towers in wind parks. A major problem has been in providing the capability to quickly combine and examine incoming data from multiple PCM sources in the field. To solve this problem, SERI has developed a low-cost PC-based PCM Telemetry Data-Reduction System (PC-PCM System) to facilitate quick, in-the-field multiple-channel data analysis. The PC-PCM System consists of two basic components. First, PC-compatible hardware boards are used to decode and combine multiple PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for use under DOS was developed to simplify data-acquisition control and management. The software, called the Quick-Look Data Management Program, provides a quick, easy-to-use interface between the PC and multiple PCM data streams. The Quick-Look Data Management Program is a comprehensive menu-driven package used to organize, acquire, process, and display information from incoming PCM data streams. The paper describes both hardware and software aspects of the SERI PC-PCM system, concentrating on features that make it useful in an experiment test environment to quickly examine and verify incoming data from multiple PCM streams. Also discussed are problems and techniques associated with PC-based telemetry data-acquisition, processing, and real-time display.

Monte Carlo dose calculation using a cell processor based PlayStation 3 system

NASA Astrophysics Data System (ADS)

Chow, James C. L.; Lam, Phil; Jaffray, David A.

2012-02-01

This study investigates the performance of the EGSnrc computer code coupled with a Cell-based hardware in Monte Carlo simulation of radiation dose in radiotherapy. Performance evaluations of two processor-intensive functions namely, HOWNEAR and RANMAR_GET in the EGSnrc code were carried out basing on the 20-80 rule (Pareto principle). The execution speeds of the two functions were measured by the profiler gprof specifying the number of executions and total time spent on the functions. A testing architecture designed for Cell processor was implemented in the evaluation using a PlayStation3 (PS3) system. The evaluation results show that the algorithms examined are readily parallelizable on the Cell platform, provided that an architectural change of the EGSnrc was made. However, as the EGSnrc performance was limited by the PowerPC Processing Element in the PS3, PC coupled with graphics processing units or GPCPU may provide a more viable avenue for acceleration.

Establishing a communications link between two different, incompatible, personal computers: with practical examples and illustrations and program code.

PubMed

Davidson, R W

1985-01-01

The increasing need to communicate to exchange data can be handled by personal microcomputers. The necessity for the transference of information stored in one type of personal computer to another type of personal computer is often encountered in the process of integrating multiple sources of information stored in different and incompatible computers in Medical Research and Practice. A practical example is demonstrated with two relatively inexpensive commonly used computers, the IBM PC jr. and the Apple IIe. The basic input/output (I/O) interface chip for serial communication for each computer are joined together using a Null connector and cable to form a communications link. Using BASIC (Beginner's All-purpose Symbolic Instruction Code) Computer Language and the Disk Operating System (DOS) the communications handshaking protocol and file transfer is established between the two computers. The BASIC programming languages used are Applesoft (Apple Personal Computer) and PC BASIC (IBM Personal computer).

Occurrence and Distribution of Pesticides in the St. Lucie River Watershed, South-Central Florida, 2000-01, Based on Enzyme-Linked Immunosorbent Assay (ELISA) Screening

USGS Publications Warehouse

Lietz, A.C.

2003-01-01

The St. Lucie River watershed is a valuable estuarine ecosystem and resource in south-central Florida. The watershed has undergone extensive changes over the last century because of anthropogenic activities. These activities have resulted in a complex urban and agricultural drainage network that facilitates the transport of contaminants, including pesticides, to the primary canals and then to the estuary. Historical data indicate that aquatic life criteria for selected pesticides have been exceeded. To address this concern, a reconnaissance was conducted to assess the occurrence and distribution of selected pesticides within the St. Lucie River watershed. Numerous water samples were collected from 37 sites among various land-use categories (urban/built-up, citrus, cropland/pastureland, and inte-grated). Samples were collected at inflow points to primary canals (C-23, C-24, and C-44) and at control structures along these canals from October 2000 to September 2001. Samples were screened for four pesticide classes (triazines, chloroacetanilides, chlorophenoxy compounds, and organophosphates) by using Enzyme-Linked Immunosorbent Assay (ELISA) screening. A temporal distribution of pesticides within the watershed was made based on samples collected at the integrated sites during different rainfall events between October 2000 and September 2001. Triazines were detected in 32 percent of the samples collected at the integrated sites. Chloroacetanilides were detected in 60 percent of the samples collected at the integrated sites, with most detections occurring at one site. Chlorophenoxy compounds were detected in 17 percent of the samples collected at the integrated sites. Organophosphates were detected in only one sample. A spatial distribution and range of concentration of pesticides at the 37 sampling sites in the watershed were determined among land-use categories. Triazine concentrations ranged from highest to lowest in the citrus, urban/built-up, and integrated areas, respectively. The highest median triazine concentration was found in the cropland/pastureland area. Chloroacetanilide concentra-tions ranged from highest to lowest in the citrus, integrated, urban/built-up, and cropland/pastureland areas, respectively. Chlorophenoxy compound concentrations ranged from highest to lowest in the urban/built-up, integrated, citrus, and cropland/pastureland areas, respectively. The maximum concentrations of triazines, chloroacetanilides, and chlorophenoxy compounds were 0.63, 1.0, and 14 micrograms per liter, respectively. Organophosphate was detected once at an integrated site at a concentration of 0.20 microgram per liter. Currently, the U.S. Environmental Protection Agency has no aquatic life guidelines for atrazine and metolachlor. However, assuming that all triazine and metolachlor concentrations from ELISA and gas chromatography/mass spectrometry (GC/MS) analyses were the result of atrazine and metolachlor detections, no concentrations exceeded the Canadian aquatic life guidelines for atrazine and metolachlor. One organophosphate detection (0.2 microgram per liter) did exceed the U.S. Environmental Protection Agency aquatic life guideline for chlorpyrifos. The deethylatrazine/atrazine ratio (DAR) is an important indicator of atrazine transport in the environment. The DAR ranged from 0.25 to 0.33, indicating that postapplication runoff was the most likely source of atrazine to the environment at the time of sampling. Deisopropylatrazine is a metabolite of atrazine and structurally similar compounds, such as simazine and cyanazine. The deisopropylatrazine/deethylatrazine ratio (D2R) is an indicator of nonpoint sources of deisopropylatrazine to the environment. The ratio ranged from 1 to 3 in this study, indicating simazine was an important source of deisopropylatrazine to the environment at the time of sampling, as opposed to atrazine alone. Confirmation analyses by GC/MS for triazines detected by ELISA indicated t

Linking ground-water age and chemistry data along flow paths: Implications for trends and transformations of nitrate and pesticides

USGS Publications Warehouse

Tesoriero, A.J.; Saad, D.A.; Burow, K.R.; Frick, E.A.; Puckett, L.J.; Barbash, J.E.

2007-01-01

Tracer-based ground-water ages, along with the concentrations of pesticides, nitrogen species, and other redox-active constituents, were used to evaluate the trends and transformations of agricultural chemicals along flow paths in diverse hydrogeologic settings. A range of conditions affecting the transformation of nitrate and pesticides (e.g., thickness of unsaturated zone, redox conditions) was examined at study sites in Georgia, North Carolina, Wisconsin, and California. Deethylatrazine (DEA), a transformation product of atrazine, was typically present at concentrations higher than those of atrazine at study sites with thick unsaturated zones but not at sites with thin unsaturated zones. Furthermore, the fraction of atrazine plus DEA that was present as DEA did not increase as a function of ground-water age. These findings suggest that atrazine degradation occurs primarily in the unsaturated zone with little or no degradation in the saturated zone. Similar observations were also made for metolachlor and alachlor. The fraction of the initial nitrate concentration found as excess N2 (N2 derived from denitrification) increased with ground-water age only at the North Carolina site, where oxic conditions were generally limited to the top 5??m of saturated thickness. Historical trends in fluxes to ground water were evaluated by relating the times of recharge of ground-water samples, estimated using chlorofluorocarbon concentrations, with concentrations of the parent compound at the time of recharge, estimated by summing the molar concentrations of the parent compound and its transformation products in the age-dated sample. Using this approach, nitrate concentrations were estimated to have increased markedly from 1960 to the present at all study sites. Trends in concentrations of atrazine, metolachlor, alachlor, and their degradates were related to the timing of introduction and use of these compounds. Degradates, and to a lesser extent parent compounds, were detected in ground water dating back to the time these compounds were introduced.

Dissolved triazines in watersheds under sugarcane cultivation

NASA Astrophysics Data System (ADS)

Portocarrero, Rocio; Aparicio, Virginia; De Gerónimo, Eduardo; Costa, José Luis

2017-04-01

Sugarcane is an important extensive crop in north western of Argentina. Chemical weed control have been increasing over the last years. The typical period of this practice takes place from October to December, at beginnig of rainy season. Atrazine and ametryn are the main herbicides used, they have moderate to high potential mobility in soils, which is a potential source of contamination for nearby streams. The aim of this study was to quantify both atrazine and ametryn contamination levels in two streams of the southeast of Tucuman (Argentina) under sugarcane production. This area has a subtropical climate, and a monsoon rainfall regime with an annual average of 700 mm. Five sampling points of Mista and Saladillo streams were monitored from September to April, during three growing season. In each growing season, four sampling moments were defined: M1) Before the herbicides application; M2) Beginning of the rainy season and during the chemical weed control period; M3) High accumulated rainfall; M4) End of the rainy season. Water samples were taken and stored in polypropylene bottles at -20°C until analysis. Samples were analyzed by ultra performance liquid chromatography (Waters® ACQUITY® UPLC) coupled to a mass spectrometer (MS/MS Quattro Premier XE Waters). Atrazine was quantified in all samples and the highest concentrations were found in M2 (0.03-3.07 μg L-1). For the others sampling moments, atrazine concentrations were ranged from 0.003 to 0.2 μg L-1. Ametryn was detected in the 90% of the samples. Ametryn concentrations in M2 varied from 0.004 to 0.32 μg L-1, and in the rest sampling moments were less than 0.11 μg L-1. Both herbicides were highly detected in the study area. Although atrazine is authorized for other crops in the area, ametryn is only authorized for sugarcane, the largest cultivation in the area.