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Photolysis neonicotinoid

Dominic Englert, Jochen P Zubrod, Christoph Neubauer, Ralf Schulz, Mirco Bundschuh
Systemic neonicotinoid insecticides such as imidacloprid are increasingly applied against insect pest infestations on forest trees. However, leaves falling from treated trees may reach nearby surface waters and potentially represent a neonicotinoid exposure source for aquatic invertebrates. Given imidacloprid's susceptibility towards photolysis and high water solubility, it was hypothesized that the leaves' toxicity might be modulated by UV-irradiation during decay on the forest floor, or by leaching and re-mobilization of the insecticide from leaves within the aquatic ecosystem...
May 2018: Environmental Pollution
Kifle Z Aregahegn, Michael J Ezell, Barbara J Finlayson-Pitts
The environmental fates of nitenpyram (NPM), a widely used neonicotinoid insecticide, are not well known. A thin solid film of NPM deposited on a germanium attenuated total reflectance (ATR) crystal was exposed to radiation from a low-pressure mercury lamp at 254 nm, or from broadband low pressure mercury photolysis lamps centered at 350 or 313 nm. The loss during photolysis was followed in time using FTIR. The photolysis quantum yields (), defined as the number of NPM molecules lost per photon absorbed, were determined to be (9...
January 18, 2018: Environmental Science & Technology
Kifle Z Aregahegn, Dorit Shemesh, R Benny Gerber, Barbara J Finlayson-Pitts
Imidacloprid (IMD) is the most widely used neonicotinoid insecticide found on environmental surfaces and in water. Analysis of surface-bound IMD photolysis products was performed using attenuated total reflectance Fourier transfer infrared (ATR-FTIR) analysis, electrospray ionization (ESI-MS), direct analysis in real time mass spectrometry (DART-MS), and transmission FTIR for gas-phase products. Photolysis quantum yields (ϕ) for loss of IMD were determined to be (1.6 ± 0.6) × 10(-3) (1s) at 305 nm and (8...
March 7, 2017: Environmental Science & Technology
Martin J Hilton, Tim D Jarvis, Dean C Ricketts
BACKGROUND: Thiamethoxam is a systemic and contact pesticidal active substance in the neonicotinoid class of insecticides used worldwide to control a range of insects. Recently, concerns have been expressed regarding possible effects of neonicotinoids on bees and other wildlife. The DT50 of thiamethoxam in soil may be crucial to assessing the potential long-term exposure of non-target organisms to thiamethoxam. There are currently no detailed publicly available data for the field soil degradation of thiamethoxam under European conditions...
February 2016: Pest Management Science
Valentina Colombo, Silvia Mohr, Rüdiger Berghahn, Vincent J Pettigrove
A field-based microcosm experiment was performed to investigate the effects of repeated pulses of the neonicotinoid insecticide imidacloprid on a lentic benthos assemblage. This specific microcosm method was chosen because it allows for both testing of a wide range of organisms under natural conditions and as well as gaining insight into intraspecific and interspecific interactions. The macrozoobenthos that colonised the microcosms was exposed to three pulses each 1 week apart at nominal concentrations ranging from 0...
November 2013: Archives of Environmental Contamination and Toxicology
Romina Zabar, Tilen Komel, Jure Fabjan, Mojca Bavcon Kralj, Polonca Trebše
This research focused on photocatalytic degradation of imidacloprid, thiamethoxam and clothianidin employing a tailor-made photoreactor with six polychromatic fluorescent UVA (broad maximum at 355 nm) lamps and immobilised titanium dioxide (TiO(2)) on glass slides. The disappearance was followed by high pressure liquid chromatography (HPLC-DAD) analyses, wherein the efficiency of mineralization was monitored by measurements of total organic carbon (TOC). Within 2h of photocatalysis, all three neonicotinoids were degraded following first order kinetics with rate constants k=0...
September 2012: Chemosphere
Romina Zabar, Darko Dolenc, Tina Jerman, Mladen Franko, Polonca Trebše
This work describes for the first time the photolytic and photocatalytic degradation of 6-chloronicotinic acid (6CNA) in double deionised water, which is a degradation product of neonicotinoid insecticides imidacloprid and acetamiprid, and it is known to appear in different environmental matrices. Photolytic experiments were performed with three UVA (ultraviolet A) polychromatic fluorescent lamps with broad maximum at 355 nm, while photocatalytic experiments were performed using immobilised titanium dioxide (TiO₂) on six glass slides in the spinning basket inside a photocatalytic quartz cell under similar irradiation conditions...
October 2011: Chemosphere
A Peña, J A Rodríguez-Liébana, M D Mingorance
Wastewater treatment plants receive organic contaminants, such as pesticides, which reach the sewage system from domestic, industrial or agricultural activities. In wastewater, which is a complex mixture of organic and inorganic compounds, biotic or abiotic degradation of contaminants can be affected by the presence of co-solutes. The photodecomposition in natural sunlight of two neonicotinoid insecticides, thiamethoxam and thiacloprid, was investigated in wastewater, aqueous extracts of sewage sludge and in aqueous surfactant solutions, which are abundant in wastewater...
July 2011: Chemosphere
Urh Cernigoj, Urska Lavrencic Stangar, Jaromír Jirkovský
Combining TiO(2) photocatalysis with inorganic oxidants (such as O(3) and H(2)O(2)) or transition metal ions (Fe(3+), Cu(2+) and Ag(+)) often leads to a synergic effect. Electron transfer between TiO(2) and the oxidant is usually involved. Accordingly, the degree of synergy could be influenced by TiO(2) surface area. With this in mind, the disappearance of thiacloprid, a neonicotinoid insecticide, was studied applying various photochemical AOPs and different TiO(2) photocatalysts. In photocatalytic ozonation experiments, synergic effect of three different TiO(2) photocatalysts was quantified...
May 15, 2010: Journal of Hazardous Materials
Nicole Schippers, Wolfgang Schwack
Imidacloprid, a neonicotinoid insecticide, is widely used in plant protection to prevent crop losses. The objective of this study was to show the photochemical fate of imidacloprid on plant surfaces by irradiation experiments on isolated tomato fruit cuticles and tomato fruits (Lycopersicon esculentum Mill.). Imidacloprid spiked samples were irradiated both under sunlight simulator and natural sunlight conditions for 24h, which resulted in recoveries of 23% and 24%, respectively, if isolated cuticles were studied...
January 21, 2010: Journal of Photochemistry and Photobiology. B, Biology
María L Dell'arciprete, Lucas Santos-Juanes, Antonio Arques Sanz, Rafael Vicente, Ana M Amat, Jorge P Furlong, Daniel O Mártire, Mónica C Gonzalez
The reactivity of hydroxyl radicals (HO ) towards three neonicotonoid insecticides, namely imidacloprid, thiacloprid and acetamiprid was investigated. These radicals were generated by photolysis of H(2)O(2) solutions. Flash photolysis experiments were used to determine the rate constants of 5.5 x 10(10) M(-1)s(-1), 6 x 10(10) M(-1)s(-1), and 7.5 x 10(10) M(-1)s(-1), for the reactions of HO with acetamiprid, imidacloprid, and thiacloprid, respectively. Continuous irradiation experiments in the absence and presence of H(2)O(2) allowed the identification and toxicity evaluation of the primary photo- and oxidation products of the insecticides...
July 2009: Photochemical & Photobiological Sciences
Francisco Sánchez-Bayo, Kouichi Goka
The acute toxicity of imidacloprid, a neonicotinoid insecticide, and zinc pyrithione (Zpt), a biocide used in anti-dandruff shampoos and protective antifouling paints, to three species of ostracods and two waterfleas, including Daphnia magna, was determined and compared under light and dark conditions. Under normal laboratory conditions, UV light had no significant influence on the outcome of toxicity bioassays, although in the case of imidacloprid both EC(50) and LC(50) calculated values were twice as high under the light as in the dark...
June 30, 2006: Aquatic Toxicology
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