Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient
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Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97330, USA
2
School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97330, USA
3
Oregon Nanoscience and Microtechnologies Institute, Corvallis, OR 97330, USA
*
Author to whom correspondence should be addressed.
Nanomaterials 2019, 9(1), 81; https://doi.org/10.3390/nano9010081
Received: 12 December 2018
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Revised: 31 December 2018
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Accepted: 3 January 2019
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Published: 9 January 2019
(This article belongs to the Special Issue Toxicity and Ecotoxicity of Nanomaterials)
Given the costs associated with designing novel active ingredients, new formulations focus on the use of other ingredients to modify existing formulations. Nanosized encapsulated pesticides offer a variety of enhanced features including controlled release and improved efficacy. Despite the presence of nanosized capsules in current-use pesticide formulations, the analytical and toxicological implications of encapsulation are uncertain. To explore this issue quantitatively, we fractionated the capsules of a commercially available encapsulated insecticide formulation (γ-cyhalothrin active ingredient) into two size ranges: a large fraction (LF), with an average hydrodynamic diameter (HDD) of 758 nm, and a small fraction (SF), with an average HDD of 449 nm. We developed a novel extraction method demonstrating a time-dependent inhibition of γ-cyhalothrin from capsules for up to 48 h. An acute immobilization test with a freshwater macroinvertebrate (Ceriodaphnia dubia) revealed that the SF was significantly more toxic than both the LF and the free γ-cyhalothrin treatment (EC50 = 0.18 µg/L, 0.57 µg/L, and 0.65 µg/L, respectively). These findings highlight that encapsulation of γ-cyhalothrin mitigates hydrophobic partitioning in a time-dependent manner and influences toxicity in a size-dependent manner. Recognizing the analytical and toxicological nuances of various nanosized capsules can contribute to innovation in pesticide formulations and may lead to more comprehensive pesticide regulation.
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Keywords:
nanopesticide; pyrethroid; nanoenabled; other ingredients; pesticide risk assessment; nanotoxicology; encapsulated
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MDPI and ACS Style
Slattery, M.; Harper, B.; Harper, S. Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient. Nanomaterials 2019, 9, 81. https://doi.org/10.3390/nano9010081
AMA Style
Slattery M, Harper B, Harper S. Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient. Nanomaterials. 2019; 9(1):81. https://doi.org/10.3390/nano9010081
Chicago/Turabian StyleSlattery, Matthew, Bryan Harper, and Stacey Harper. 2019. "Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient" Nanomaterials 9, no. 1: 81. https://doi.org/10.3390/nano9010081
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