Ecological Risk Assessment of Nano-enabled Pesticides: A Perspective on Problem Formulation

Walker, Glen W; Kookana, Rai S.; Smith, Natalie E.; Kah, Mélanie; Doolette, Casey L.; Reeves, Philip T.; Lovell, Wess; Anderson, Darren; Turney, Terence W.; Navarro, Divina A.

doi:10.1021/acs.jafc.7b02373

Cited by 118 publications

(78 citation statements)

References 13 publications

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“…The development of a sustainable and efficient system of food production with the involvement of nanotechnology may be an excellent strategy for revolutionizing conventional agricultural practices and thus attenuate the negative impacts of agrochemicals on the environment, as well as improving crop yield and increasing food security (Sekhon, 2014;Liu and Lal, 2015). However, some barriers still hinder the effective application of nanomaterials in agriculture, such as the lack of specific regulatory frameworks for ecological risk assessments (Walker et al, 2017) and the perception of the agricultural market concerning the potential of nanomaterials (Kah, 2015).…”

Section: Discussionmentioning

confidence: 99%

Post-Emergence Herbicidal Activity of Nanoatrazine Against Susceptible Weeds

Sousa

Gomes

Campos³

et al. 2018

Front. Environ. Sci.

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Poly(ε-caprolactone) (PCL) nanocapsules have been previously developed as a carrier system for atrazine. However, the efficacy of this nanoformulation against weeds commonly found in crop cultures has not been tested yet. Here, we evaluated the post-emergence herbicidal activity of PCL nanocapsules containing atrazine against Amaranthus viridis (slender amaranth) and Bidens pilosa (hairy beggarticks), in comparison with a commercial formulation of atrazine. For both species, treatment with atrazine-loaded nanocapsules (at 2,000 g ha −1) led to a greater decrease in the photosystem II activity (above 50% inhibition relative to the control) than the commercial atrazine formulation at the same concentration (around 40% inhibition). The growth of A. viridis plants was equally reduced by nanoatrazine and commercial formulation (above 64% for root and 75% for shoot). In the case of B. pilosa, atrazine-loaded nanocapsules decreased more effectively the root and shoot growth than the commercial formulation, leading to a loss of plant biomass. Moreover, for both species, the use of 10-fold diluted atrazine-loaded PCL nanocapsules (200 g ha −1) resulted in the same inhibitory effect in root and shoot growth as the commercial formulation at the standard atrazine dose. These results suggest that the utilization of atrazine-containing PCL nanocapsules potentiated the post-emergence control of A. viridis and B. pilosa by the herbicide. Thus, this nanoformulation emerges as an efficient alternative for weed control.

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Section: Discussionmentioning

confidence: 99%

Post-Emergence Herbicidal Activity of Nanoatrazine Against Susceptible Weeds

Sousa

Gomes

Campos³

et al. 2018

Front. Environ. Sci.

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“…Those adsorbent-pesticide preparations are lastly being labelled as nanoformulations or nanopesticides (Kah et al, 2013;Pérez-de-Luque and Hermosín, 2013;Nuruzzaman et al, 2016), but they need to be subjected to deep study to accomplish the regulatory normative that pesticides need to be authorized (Walker et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Two soil-friendly carrier materials appropriate for acid and anionic pesticides are the natural cationic or organo-modified clays (Lagaly, 2001;Celis et al, 2002Celis et al, , 2012Carrizosa et al, 2004;Hermosín et al, 2006;Radian and Mishael, 2008;Chevillard et al, 2012;Pérez-de-Luque and Hermosín, 2013;He et al, 2014;Cabrera et al, 2016;Nuruzzaman et al, 2016) and the magnesium/aluminum layered double hydroxides (Mg/Al LDH) or anionic clays (Ulibarri and Hermosin, 2001;Dupin et al, 2004;Cardoso et al, 2006;Forano et al, 2006;Bruna et al, 2009;Nuruzzaman et al, 2016), because they are based on naturally occurring soil materials and they have been shown to interact with acid and anionic organic species, which can be hosted in their interlayer spaces from where they can be slowly released (Pérez-de-Luque and Hermosín, 2013;Nuruzzaman et al, 2016). S1), is an imidazolinone systemic herbicide used either pre-or post-emergence for broad-leaved weed control in several crops such as legumes, maize or sunflower (Eizenberg et al, 2009;Walker et al, 2018). One of its main use is to control broomrape, a very severe weed which parasites the crops in the roots, living most the time in the subsoil and, once the attack is visible, it is often too late to be controlled (Cessna et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Although the Imz recommended field doses are very low, in fields where a continuous use is needed because of chronic soil infection (Xie et al, 2010), and in farm herbicide manipulation places, extensive imazamox leaching or runoff from the soil is possible (Aichele and Penner, 2005;Eizenberg et al, 2009). In fact, the presence of Imz in some environmental water samples has been reported (D'Ascenzo et al, 1998;Walker et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Cationic and anionic clay nanoformulations of imazamox for minimizing environmental risk

Khatem

Celis

Hermosı́n

2019

Applied Clay Science

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A synthesized anionic clay (layered double hydroxide or LDH) and a commercial cationic organoclay (Cloisite10A, Clo10A) were assayed as host nanocarriers for imazamox (Imz) herbicide. Imz-LDH complexes were obtained by direct synthesis (DS) and regeneration (RE), whereas Imz-Clo10A complexes were prepared by ground mixing (GM) and through methanol addition (weak [WC] and strong [SC] complexes). Characterization of the complexes showed that Imz was partially hosted in the interlayer structure of the resulting nanoherbicides, as anion or as neutral molecule, with some of the herbicide at the external surfaces, depending on the carrier and preparation. The nanoherbicides showed a total water release from 73 (Imz-LDH DS) to 98% (Imz-Clo10A GM) with an immediate release from 67 (Imz-LDH DS) to 93% (Imz-Clo10A GM), while technical Imz released instantaneously >98%. The herbicide maximum concentration in the leachates from Imztreated soil columns decreased between 20 and 35% for nanoherbicides with respect to the technical Imz, and between 10 and 30% with respect to a commercial Imz formulation. Total herbicide soil leaching losses were reduced from 96 or 90%, for technical and commercial Imz, to 77-67% for nanoherbicides. Bioassays showed similar efficacy for nanoherbicides and commercial product. The diverse Imz-clay complexes are revealed as smart delivery systems for this systemic herbicide by decreasing Imz water pollution risk while maintaining efficacy, with the advantages of their soil compatible matrix and the possibility to be located at action point in the subsoil.

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“…contained in sludge used as fertilisers. For the specific issues that relate to the ERA of nanoenabled pesticides, an overview undertaken by researchers and the Australian authorities can be found in Walker et al (2018). As an example, the work of Elmer and White (2016) on the application side for plant protection using different fate and uptake behaviours of nanoforms is illustrative.…”

Section: Quantification Of Exposure Uptake Kinetics and Effectsmentioning

confidence: 99%

Using problem formulation for fit‐for‐purpose pre‐market environmental risk assessments of regulated stressors

Devos

Devlin

Ippolito

et al. 2019

EFS2

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Pre-market/prospective environmental risk assessments (ERAs) contribute to risk analyses performed to facilitate decisions about the market introduction of regulated stressors. Robust ERAs begin with an explicit problem formulation, which involves among other steps: (1) formally devising plausible pathways to harm that describe how the deployment of a regulated stressor could be harmful; (2) formulating risk hypotheses about the likelihood and severity of such events; (3) identifying the information that will be useful to test the risk hypotheses; and (4) developing a plan to acquire new data for hypothesis testing should tests with existing information be insufficient for decision-making. Here, we apply problem formulation to the assessment of possible adverse effects of RNA interference-based insecticidal genetically modified (GM) plants, GM growth hormone coho salmon, gene drive-modified mosquitoes and classical biological weed control agents on non-target organisms in a prospective manner, and of neonicotinoid insecticides on bees in a retrospective manner. In addition, specific considerations for the problem formulation for the ERA of nanomaterials and for landscape-scale population-level ERAs are given. We argue that applying problem formulation to ERA maximises the usefulness of ERA studies for decision-making, through an iterative process, because: (1) harm is defined explicitly from the start; (2) the construction of risk hypotheses is guided by policy rather than an exhaustive attempt to address any possible differences; (3) existing information is used effectively; (4) new data are collected with a clear purpose; (5) risk is characterised against well-defined criteria of hypothesis corroboration or falsification; and (6) risk assessment conclusions can be communicated clearly. However, problem formulation is still often hindered by the absence of clear policy goals and decision-making criteria (e.g. definition of protection goals and what constitutes harm) that are needed to guide the interpretation of scientific information. We therefore advocate further dialogue between risk assessors and risk managers to clarify how ERAs can address policy goals and decision-making criteria. Ideally, this dialogue should take place for all classes of regulated stressors, as this can promote alignment and consistency on the desired level of protection and maximum tolerable impacts across regulated stressors.

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Ecological Risk Assessment of Nano-enabled Pesticides: A Perspective on Problem Formulation

Cited by 118 publications

References 13 publications

Post-Emergence Herbicidal Activity of Nanoatrazine Against Susceptible Weeds

Post-Emergence Herbicidal Activity of Nanoatrazine Against Susceptible Weeds

Cationic and anionic clay nanoformulations of imazamox for minimizing environmental risk

Using problem formulation for fit‐for‐purpose pre‐market environmental risk assessments of regulated stressors

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