Transfluthrin indoor air concentration and inhalation exposure during application of electric vaporizers

International audienceDifferent household insecticide applications via two electric vaporizers emitting transfluthrin were realized in a full-scale experimental room under controlled air exchange rate conditions. On-line high-time resolved measurements of the gas-phase concentrations of the active substance during and immediately after the spreading periods were performed with a High Sensitivity Proton-Transfer-Reaction Mass Spectrometer (HS-PTR-MS). Experimental and modelled data from the ConsExpo 4.0 software were also compared to evaluate the sources of differences. Different application scenarios were also compared. Averaged inhaled concentrations over 1h, 1week, and 5months were estimated to be 8.3, 1.8, and 1.8μg.m(-3), respectively. Corresponding margins of exposures range from 1000 to 10,000, claiming for the absence of effect. Dermal and dust ingestion pathways, although roughly estimated, seems being non-negligible. This claims for a more in-depth integrated risk assessment

Widespread pesticide distribution in the European atmosphere questions their degradability in air

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved

Widespread pesticide distribution in the European atmosphere questions their degradability in air

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved

Modélisation de la qualité de l’air : vers l’évaluation de l’exposition atmosphérique aux pesticides

International audienceDetermining atmospheric exposure is critical to assess the health impact of pesticides, but few tools currently exist to map pesticide concentrations at the national scale. One possible method would be to use air quality models such as the CHIMERE model to simulate pesticide atmospheric concentrations. This type of model represents the physicochemical processes occurring in the atmosphere to calculate concentrations of various chemicals. A method has recently been developed in the CHIMERE model to simulate pesticide concentrations by incorporating a volatilization flux model to calculate emissions to air from treated surfaces. Using such a method would require knowledge of the spatial and temporal distribution of pesticide applications. While data from the Banque nationale des ventes de produits phytopharmaceutiques par les distributeurs agréés spatialisée (BNVD-S) provides a good indication of the spatial distribution of applications, little information exists on treatment schedules. Although such models operate at resolutions of a few kilometers (which would not allow a reliable determination of exposure), it would be possible to determine high-resolution pesticide maps over the whole France using downscaling approaches combined with results from local-scale dispersion models. Such a method would eventually provide maps of pesticide concentrations for epidemiological studies.La détermination de l’exposition atmosphérique est critique pour évaluer l’impact sanitaire des pesticides mais peu d’outils permettent actuellement de réaliser une cartographie des concentrations à l’échelle nationale. Une méthode possible consisterait à utiliser des modèles de qualité de l’air comme le modèle CHIMERE pour simuler les concentrations de pesticides. Ce genre de modèle représente les processus physico-chimiques intervenant dans l’atmosphère pour calculer les concentrations de diverses substances. Une méthode a été récemment développée dans le modèle CHIMERE pour simuler les concentrations de pesticides en intégrant un modèle de calcul de flux de volatilisation afin de calculer les émissions dans l’air depuis les surfaces traitées. Utiliser une telle méthode exigerait de connaître la distribution spatiale et temporelle des applications de pesticides. Si la spatialisation des données de la Banque nationale des ventes de produits phytopharmaceutiques par les distributeurs agréés spatialisée (BNVD-S) fournit une bonne indication sur la distribution spatiale des applications en France, peu d’informations existent sur les calendriers de traitement. Bien que ce genre de modèles fonctionne à des résolutions de quelques kilomètres (ce qui ne permettrait pas une détermination fiable de l’exposition), il serait possible de déterminer des cartographies à haute résolution de pesticides sur l’ensemble de la France en utilisant des approches de descente d’échelle combinées à des résultats de modèles de dispersion à l’échelle locale. Une telle méthode permettrait à terme de fournir des cartographies de concentrations de pesticides pour les études épidémiologiques

Heterogeneous atmospheric degradation of current-use pesticides by nitrate radicals

International audienc

Heterogeneous degradation of pesticides by OH radicals in the atmosphere: Influence of humidity and particle type on the kinetics

International audiencePesticides can be adsorbed on the surface of atmospheric aerosol, depending on their physicochemical properties. They can be degraded by atmospheric oxidants such as OH radicals but the influence of some environmental parameters on the degradation kinetics, especially relative humidity and particle surface type, is not well understood. Heterogeneous degradation by OH radicals of eight commonly used pesticides (i.e., difenoconazole, tetraconazole, cyprodinil, fipronil, oxadiazon, pendimethalin, deltamethrin, and permethrin) adsorbed on hydrophobic and hydrophilic silicas at a relative humidity ranging from 0% to 70% was studied. Under experimental conditions, only cyprodinil, deltamethrin, permethrin, and pendimethalin were degraded by OH radical in atmospheric relevant concentration. Second-order kinetic constants calculated for the pesticides degraded by OH radicals ranged from (1.93 ± 0.61) × 10−13 cm3 molecule−1 s−1 (permethrin, hydrophobic silica, 30% RH) to (4.08 ± 0.27) × 10−12 cm3 molecule−1 s−1 (pendimethalin, hydrophilic silica, 0% RH). Results obtained can contribute to improve the understanding of the atmospheric fate of pesticides and other semi-volatile organic compounds in the particulate phase and they highlight the importance of taking humidity and particle type into account for the determination of pesticides atmospheric half-lives

Crystal and molecular structure of bis(imazapyr)diaqua copper(II)

International audienceThe imidazolinone herbicide imazapyr, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid (H(2)imz) interacts with Cu(II) leading to [Cu(Himz)(2)(H2O)(2)] which crystallizes in the space group Pbca, with a = 12.5370(3) Angstrom, b = 19.8500(5) Angstrom, c = 22.7720(9) Angstrom, and Z = 8. The Cu(II) atom is octahedrally surrounded by four nitrogen atoms of two Himz(-) anions and two water molecules. Each Himz(-) acts as a chelating ligand by means of N pyridine and N lactam atoms leading to five-membered chelate rings. The Cu-N distances vary from 1.948(4) to 2.299(5) Angstrom while the Cu-O are 2.114(5) and 2.256(6) Angstrom. The imidazol N-H are involved in short intramolecular hydrogen bonds with the carboxylate groups. The structure is stabilized by an intermolecular hydrogen-bonded network involving the water molecules and the carboxylate groups

Heterogeneous atmospheric degradation of pesticides by ozone: Influence of relative humidity and particle type

International audienceIn the atmosphere pesticides can be adsorbed on the surface of particles, depending on their physico-chemical properties. They can react with atmospheric oxidants such as ozone but parameters influencing the degradation kinetics are not clear enough. In this study the heterogeneous ozonolysis of eight commonly used pesticides (i.e., difenoconazole, tetraconazole, cyprodinil, fipronil, oxadiazon, pendimethalin, deltamethrin, and permethrin) adsorbed on hydrophobic and hydrophilic silicas, and Arizona dust at relative humidity ranging from 0% to 80% was investigated. Under experimental conditions, only cyprodinil, deltamethrin, permethrin and pendimethalin were degraded by ozone. Second-order kinetic constants calculated for the pesticides degraded by ozone ranged from (4.7 ± 0.4) × 10−20 cm3 molecule−1 s−1 (pendimethalin, hydrophobic silica, 55% RH) to (2.3 ± 0.4) × 10−17 cm3 molecule−1 s−1 (cyprodinil, Arizona dust, 0% RH). Results obtained can contribute to a better understanding of the atmospheric fate of pesticides in the particulate phase and show the importance of taking humidity and particle type into account for the determination of pesticides atmospheric half-lives

Sprays and diffusers as indoor air fresheners: Exposure and health risk assessment based on measurements under realistic indoor conditions

International audienceNoncombustible air fresheners are indoor air emission sources of concern. The associated health risks should be better understood. Based on 15 products (4 sprays, 6 passive diffusers, and 5 active diffusers), the health risk assessment (HRA) approach was applied to a national use survey in France and to concentrations measured in an experimental house. The targeted substances included volatile organic compounds (VOCs), carbonyls, and fine particles (PM2.5). Mean-use and reasonable worst-case generic scenarios were designed. No situation of concern occurred regarding chronic exposure associated with the mean use. Under the reasonable worst-case scenarios, the chronic risk could exceed selected health reference standards, mainly for acrolein (average inhaled concentration (AIC) up to 3.5 µg/m3), benzene (AIC up to 4 µg/m3), and limonene (AIC up to 8 mg/m3). The acute exposure, defined as a 1-h exposure, could exceed selected health standards, primarily for acrolein (up to 23 µg/m3) and formaldehyde (up to approximately 370 µg/m3). Furthermore, the 1-h average PM2.5 concentration, including ultrafine particles, could exceed 100 µg/m3, typically for sprays. These results suggest that the highest exposures should be reduced and, as such, that the emissions of the highest-emissivity products should be lowered

Influence of pesticide concentration on their heterogeneous atmospheric degradation by ozone

International audienc