%0 Journal Article
%T Pesticide Encapsulation at the Nanoscale Drives Changes to the Hydrophobic Partitioning and Toxicity of an Active Ingredient
%A Bryan Harper
%A Matthew Slattery
%A Stacey Harper
%J Archive of "Nanomaterials".
%D 2019
%R 10.3390/nano9010081
%X 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 (¦Ã-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 ¦Ã-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 ¦Ã-cyhalothrin treatment (EC50 = 0.18 ¦Ìg/L, 0.57 ¦Ìg/L, and 0.65 ¦Ìg/L, respectively). These findings highlight that encapsulation of ¦Ã-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
%K nanopesticide
%K pyrethroid
%K nanoenabled
%K other ingredients
%K pesticide risk assessment
%K nanotoxicology
%K encapsulated
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6358805/