Zooplankton community responses to the mixture of imazethapyr with imazapic and bispyribac-sodium herbicides under rice paddy water conditions

Reimche, Geovane Boschmann; Machado, Sérgio Luiz de Oliveira; Zanella, Renato; Vicari, Michele Camara De; Piccinini, Fernando; Golombieski, Jaqueline Ineu; Reck, Liange

doi:10.1590/0103-8478cr6151

Cited by 5 publications

(5 citation statements)

References 19 publications

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“…Under an IF regime, the half-life of imazapic was higher than it was under CF, with DT 50 values of approximately 5 d for both sowing dates. Similar results were found by others, who estimated the DT 50 for imazapic to be approximately 4 d under CF (Reimche et al 2014).…”

Section: Resultssupporting

confidence: 90%

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Dissipation of Clomazone, Imazapyr, and Imazapic Herbicides in Paddy Water under Two Rice Flood Management Regimes

Schreiber¹,

Scherner

Massey

et al. 2017

Weed Technol

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Since its beginning in 1993, FOCUS (FOrum for the Co-ordination of pesticide fate models and their USe) has established a number of work groups to develop procedures for estimating concentrations of plant protection products and their metabolites in various environmental compartments (ground water, surface water, soil, sediment, and air). One of the most important parameters in these environmental assessments is the degradation of these compounds. Although the procedures for conducting the laboratory and field studies measuring degradation are specified in study guidelines, the procedures for calculating degradation rates have not been standardised. The general procedures for calculating degradation rates are well known but the assumptions made during this process can appreciably affect the results. Therefore FOCUS established a work group of experts from regulatory authorities, research institutes, and industry to develop recommendations for calculating degradation kinetics in the EU registration process. This FOCUS group met nine times between September 2002 and January 2005, carefully considered the comments of the member states to an initial draft of its findings, and prepared version 1.0 of this report in In response to the comments made by the EFSA PPR Panel, the FOCUS Steering Committee (SC) asked the work group to produce this final version (version 2.0) of the report.The SC reacts to the recommendations by the Panel as follows:(1a) This chapter was not part of the remit of this work group and would lead to a considerable delay in the finalisation of this guidance document which the SC considers undesirable. Therefore the SC decided not to follow this recommendation.However, new Section 11.5 was added to the guidance document that gives some reflections on this matter. (4) Several companies have taken the initiative to develop such software, which is expected to become available in 2006. However, the guidance described in the report has been designed to be generally applicable, independent of specific software tools.(5) The SC agrees that reviewing such experiences is necessary. However, the first step is to collect and report these experiences systematically. The SC cannot commit a FOCUS work group to this task because such experiences are gained in the EU risk assessment procedure co-ordinated by the EFSA PRAPeR team. The SC suggests therefore that this team collects and reports these experiences.The calculation of kinetic parameters is a fundamental component of environmental risk assessments of plant protection products. The recommendations of this report can and will impact the evaluation process. These impacts include more complex evaluation processes, more detailed documentation of calculations, and potentially the need to conduct additional experimental studies. Therefore, the FOCUS Steering Committee recommends the following Page 5 phased approach to the introduction of the recommendations: All regulatory studies that include estimation of degradation kinetics completed later than nine months a...

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Section: Resultssupporting

confidence: 90%

“…Pesticide dissipation in paddy water has been studied extensively (Martini et al 2013; Reimche et al 2014; Santos et al 2008; Tomco et al 2010; Wang et al 2006; Watanabe et al 2007; Wei et al 2015). However, the impact of water-saving flood management practices, such as intermittent flooding, on pesticide dissipation has not been determined.…”

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confidence: 99%

Dissipation of Clomazone, Imazapyr, and Imazapic Herbicides in Paddy Water under Two Rice Flood Management Regimes

Schreiber¹,

Scherner

Massey

et al. 2017

Weed Technol

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“…The dissipation time (DT50), i.e. the time taken for the concentration of the pesticide to be reduced to 50% of its initial concentration, was calculated using the equation DT50=ln(2)/k, where k is the absolute value of the slope and the first-order rate constant for the herbicide [15]. Figs.…”

Section: Resultsmentioning

confidence: 99%

“…However, the degradation of imazapic by sunlight is believed to be minimal when it is applied to terrestrial plants or soil, but it is rapidly degraded by sunlight in aqueous solutions [16]. Imazapyr residues can be relatively persistent in soils (reported soil half-life (t50) = 25-142 days) depending on soil texture, organic matter content, pH levels and environmental factors that promote microbial degradation [10][11][12][13][14][15][16][17].…”

Section: Resultsmentioning

confidence: 99%

Persistence of Imazapic and Imazapyr in Paddy Soil and Water

2016

IJAAEE

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Abstract-Studies on the persistence of imazapic and imazapyr in a Malaysian soil, namely clay loam and in water, were conducted under greenhouse conditions. The experiment was carried out in clay loam soil of the Sungai Besar paddy plantation area, in Selangor, Malaysia. An analytical method based on an extraction procedure and followed by high-performance liquid chromatographic (HPLC) separation with multi variable detection was optimized and validated for the simultaneous determination of imazapyr and imazapic. Chromatographic separation was carried out with the C8 column. The estimated values of the half-life of imazapyr in water for 75, 150 and 300 g ai/ha following first order kinetics were 22.00, 23.34 and 22.29 days, respectively. Meanwhile for imazapic, the estimated half-life in water for 75, 150 and 300 g ai/ha following first order kinetics were 23.11, 23.74 and 21.59 days, respectively. As for soil, the degradation rates of 26.26, 29.75 and 25.30 days were observed as the estimated half-life values for imazapyr and 38.51, 34.15 and 25.02 days for imazapic for the treatments of 75, 150 and 300 g ai/ha respectively. The rates of degradation of both active ingredients were slower in soil than in water. These results are informative to both farmers and researchers to enable them to keep track on the environmental effects of selected herbicides so that the probability of unwanted ecological effects can be minimized.

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“…Além do mais, foi observado que Clorophyceae são mais afetada no agroecossistema arroz durante seu ciclo com testes com os herbicidas clomazone e quincloraque (Figueiredo et al 2012). Reimche et al (2014) constataram que os herbicidas imazetapir e imazapique, grupo químico das imidazolinonas, afetaram a comunidade zooplanctônica com aumento na densidade de cladóceros e copépodes, também em lavouras de arroz.…”

Section: Introductionunclassified

Efeito Dos Herbicidas Imazapir E Imazapique Na Comunidade Fitoplanctônica Em Lavoura De Arroz Irrigado

Reck¹,

Reimche²,

Alves³

et al. 2018

Iheringia Ser Bot

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RESUMO -Diante da toxicidade de herbicidas aos organismos aquáticos, comumente utilizados em lavouras de arroz irrigado, o presente trabalho visou avaliar o efeito toxicológico da mistura herbicida imazapir+imazapique (Kifi x ® ) e compostos isolados na comunidade fi toplanctônica utilizando mesocosmos. Os efeitos destes contaminantes foram avaliados por delineamento experimental em blocos ao acaso com esquema fatorial (5 x 3) e quatro repetições, totalizando 16 parcelas amostrais. Este estudo demonstrou pela Principal Curva de Resposta (PRC) que os herbicidas imazapir+imazapique (Kifi x ® ), imazapir e imazapique proporcionam efeito sobre a abundância e composição do fi toplâncton. Os maiores efeitos dos herbicidas em estudo foram encontrados sobre táxons pertencentes às classes Cyanophyceae, Chlamydophyceae e Chlorophyceae. Os tratamentos com herbicidas assemelharam-se ao controle na última coleta, constatando que os herbicidas são mais tóxicos nos primeiros dias após a aplicação. Palavras-chave: algas, imidazolinonas, mesocosmos, Oryza sativaABSTRACT -Eff ect of herbicides imazapyr and imazapicon in the phytoplanktonic community of rice paddy fi elds. Considering the toxicity of herbicides commonly used in irrigated rice fi elds to aquatic organisms, this study aimed to assess the toxic eff ects of the mixture imazapyr+imazapic (Kifi x®), and also of the isolated compounds on the phytoplankton community using experiments in mesocosms. The eff ects of these contaminants were examined through experimental design with random blocks (5 x 3) and four repetitions, totaling in 16 sampling units. Using a principal response curves analysis (PRC), the experiment demonstrated that the compound imazapyr + imazapic (Kifi x®), and the single products imazapyr and imazapic have strong eff ects on the composition and abundance of phytoplankton communities. The greatest eff ects were found on three classes of microalgae Cyanophyceae, Chlamydophyceae and Chlorophyceae. The communities treated with the herbicides closely resembled the control blocks on the last sampling day, showing that the toxic eff ects are more pronounced within the fi rst days of application.

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Zooplankton community responses to the mixture of imazethapyr with imazapic and bispyribac-sodium herbicides under rice paddy water conditions

Abstract: The aim of this study was to assess the effect of concentrations of imazethapyr, imazapic, and bispyribac-sodium herbicides on zooplankton community (Cladocer, Copepod and Rotifer)

Cited by 5 publications

References 19 publications

Dissipation of Clomazone, Imazapyr, and Imazapic Herbicides in Paddy Water under Two Rice Flood Management Regimes

Dissipation of Clomazone, Imazapyr, and Imazapic Herbicides in Paddy Water under Two Rice Flood Management Regimes

Persistence of Imazapic and Imazapyr in Paddy Soil and Water

Efeito Dos Herbicidas Imazapir E Imazapique Na Comunidade Fitoplanctônica Em Lavoura De Arroz Irrigado

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