Indoor Behavior and Risk Assessment Following Space Spraying of d-Tetramethrin and d-Resmethrin

Matoba, Yoshihide; Takimoto, Yoshiyuki; Kato, Takashi

doi:10.1202/0002-8894(1998)059<0181:ibaraf>2.0.co;2

Cited by 3 publications

(8 citation statements)

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“…The shape of the treated room (3.6 m Lϫ2.7 m Wϫ 2.4 m H) was the same as previously reported. 13) As the air exchange rate of a typical room without occupants has been consistently measured at about 0.5/hr, 14) a recent Japanese government guideline uses this rate as the worst-case scenario for measuring the pesticide concentration in indoor air. 15) When a room is occupied, the authors believe the worst-case scenario should be higher, and a rate of 1.5/hr [ϭ25.5 m 3 / hr/personϫ(90%ϩ50%)persons/(3.6ϫ2.7ϫ2.4 m…”

Section: Floor Residue Distribution After 12 Hr Of Evaporation (Expermentioning

confidence: 99%

“…For carpet and wood flooring, the worst-case DT 50 of prallethrin was assumed to be 100 days, based on values of 13 to 75 days for d-tetramethrin and d-phenothrin on wood flooring and wall paper 13,23) (longer than the DT 50 of 5.9Ϯ5.0 days on foliage for pyrethroids 24) because the room materials have a high antioxidant content). During the seven-day evaporation period, the level of residue on tatami approached a plateau, while levels on carpet and wood kept increasing due to the long DT 50 (Fig.…”

Section: Tr(t)ϭ(e/k)(1ϫementioning

confidence: 99%

“…13) In some cases the wipe test was performed on the same strips three times in a row, to evaluate transfer efficiency when a human touches the same treated area several times. After completion of the final sampling in each test, the room was cleaned using paper wipers dipped in methanol, and the strips of floor materials were replaced.…”

Section: Transferable Floor Residues (Experiments 3)mentioning

confidence: 99%

“…3 )] has been used to represent a room when a woman and infant are present, 13) based on a fresh air requirement of more than or equal to 25.5 m 3 /hr/person to prevent respiratory infection and an offensive accumulation of body odors. 16) An electric vaporizer placed in the center of the floor, about 60 cm from the inlet, dispersed a 0.87% (w/w) liquid formulation containing prallethrin for 12 hr.…”

Section: Floor Residue Distribution After 12 Hr Of Evaporation (Expermentioning

confidence: 99%

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Clarifying Behavior of Prallethrin Evaporated from an Electric Vaporizer on the Floor and Estimating Associated Dermal Exposure

2004

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Systemic exposure to household pesticides may occur via inhalation, oral and dermal routes. For inhalation and oral routes, there are guidelines for estimating exposure (mg-pesticide/kg-bw/day) 1-4) using similar methodologies. Inhalation exposure is calculated from airborne concentration (mg-pesticide/m 3 ), breathing rate (m 3 /hr), absorption rate via inhalation (usually 100%, 5-7) 75% 8) or 50% 9) ), exposure period (hr/day), and body weight (kg-bw). Oral exposure is calculated from residue on dishes (mg-pesticide/g-food, or mg-pesticide/cm 2 -dish), quantity consumed (g-food/day, or cm 2 -dish/day) and body weight (kg-bw) 10) ; and/or from residue on hands (mgpesticide/cm 2 -hand), surface area licked (usually 20 cm 2 ), licking frequency (times/hr), saliva extraction factor (usually 50%), exposure period (hr/day) and body weight (kg-bw). 2)Dermal exposure is more challenging to estimate, especially during the post-application phase, because it varies more widely with age, activity, and pesticide use. The US EPA method for estimating dermal exposure uses surfaces-tobody transferable residue (mg-pesticide/cm 2 -surface), transfer coefficients for specific activities (cm 2 -surface/hr), exposure period and body weight.1,2) With the EPA method, transferable residue does not take account of repeated application, and the transfer coefficient does not take account of the clothes effects; estimates using the method are quite conservative compared to actual measured values. 11,12) In the present study, the EPA method was modified by incorporating measurements of floor residue into the estimation of dermal exposure.Floor residue characteristics were investigated for the pyrethroid prallethrin [(S)-2-methyl-4-oxo-3-(2-propynyl)-cyclopent-2-enyl (1R)-cis-trans-chrysanthemate], delivered through an electric vaporizer of the type commonly used in homes for mosquito control. Floor residue was measured in three ways: distribution after one day (12 hr) of evaporation, a time-dependent profile during 30 days of evaporation, and amount of transferable residue over time on various floor materials (tatami, carpet, wood). MATERIALS AND METHODS Floor Residue Distribution after 12 hr of Evaporation (Experiment 1)The floor of a typical Japanese residential room (Fig. 1) was covered with bleached cotton sheets that were pre-washed with n-hexane and dried at ambient temperature, as shown in Fig. 2. The shape of the treated room (3.6 m Lϫ2.7 m Wϫ 2.4 m H) was the same as previously reported.13) As the air exchange rate of a typical room without occupants has been consistently measured at about 0.5/hr, 14) a recent Japanese government guideline uses this rate as the worst-case scenario J. Pestic. Sci., 29(4), 313-321 (2004) * To whom correspondence should be addressed. © Pesticide Science Society of Japan Clarifying Behavior of Prallethrin Evaporated from an Electric Vaporizer on the Floor and Estimating Associated Dermal ExposureYoshihide MATOBA,* Ayumu INOUE and Yoshiyuki TAKIMOTO Environmental Health Science Laboratory, Sumito...

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Section: Floor Residue Distribution After 12 Hr Of Evaporation (Expermentioning

confidence: 99%

Section: Tr(t)ϭ(e/k)(1ϫementioning

confidence: 99%

Section: Transferable Floor Residues (Experiments 3)mentioning

confidence: 99%

Section: Floor Residue Distribution After 12 Hr Of Evaporation (Expermentioning

confidence: 99%

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Clarifying Behavior of Prallethrin Evaporated from an Electric Vaporizer on the Floor and Estimating Associated Dermal Exposure

2004

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“…For the safety assessment of pesticides on humans, simulation models have been developed for four such methods: space spraying, 1,2 electric vaporizing, [2][3][4] broadcast spraying, 2,5 and residual spraying. 6 By further improving the BASIC program used for the evaluation of space spraying, user-friendly software for space spraying has been developed that utilizes Excel running under Microsoft Windows on a personal computer. Called InPest, this new program is able to simulate the indoor behavior of sprayed pesticides, compute exposure levels for both applicators and occupants including children, and calculate the margins of exposure through comparisons with the toxicological data for pesticides obtained from animal experiments.…”

Section: Introductionmentioning

confidence: 99%

Development of the Simulation Model InPest for Prediction of the Indoor Behavior of Pesticides

Matoba

Yoshimura

Ohnishi

et al. 1998

Journal of the Air & Waste Management Association

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The objective was to develop a computer software package (to be registered as InPest) that runs under Microsoft Excel on a personal computer to help in the risk assessment of indoor-use pesticides for both applicators and indoor occupants for various methods of application including space spraying, electric vaporizing, broadcast spraying, and residual spraying. For space spraying, the movement of the pesticide in a sprayed room including droplet settlement, permeation into the floor, degradation, transference, and discharge by ventilation were described as precisely as possible by various physicochemical equations. The equations thus obtained were then incorporated into the Fugacity model (Level IV).When pesticide information regarding molecular weight, vapor pressure, water solubility, and octanol/water partition coefficient is available, InPest is able to simulate IMPLICATIONS There are several computer models for simulating the indoor behavior of chemicals. However, they are incapable of predicting the movement, and thus the concentration of chemicals in all room media including floor, wall, and ceiling materials as well as aerosol droplets floating in the air. A simulation model (InPest) was developed by the authors based on the Fugacity model, taking into account the generation of aerosol and vapor, settling and horizontal movement of droplets, changes in droplet diameter, and adsorption and dissipation. Using this model, improved and more detailed prediction of movement was achieved. Utilizing the BASIC programming language, user-friendly software that runs under Microsoft-Excel was developed. Called InPest, it can be used as a risk assessment tool to evaluate the safety of an indoor-use pesticide by comparing the mammalian toxicological levels with the estimated exposure to the pesticide of room occupants. The InPest concept can also be applied to simulation of the indoor behavior of other chemicals besides pesticides.the time-dependent concentrations of the pesticide in the air and residual amounts on floor, wall, and ceiling materials under various conditions. Simulation data indicate that the predicted behavior of pesticides fully agrees with the measured data. Based on the predicted concentrations in the air and amounts of residue on the floor, the levels of exposure to room occupants via inhalation, dermal, or oral intake can be computed and compared with the mammalian toxicological data. Thus, InPest is a powerful tool for evaluating the safety of indoor-use pesticides with regard to human health. INTRODUCTIONIn order to control household flies, mosquitoes and cockroaches, indoor-use pesticides are applied indoors using various methods. For the safety assessment of pesticides on humans, simulation models have been developed for four such methods: space spraying, 1,2 electric vaporizing,

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Fugacity model incorporating computational fluid dynamics for analyzing the behavior of an insecticide sprayed indoors

Tanaka,

Matoba,

Kondo

et al. 2023

J. Pestic. Sci.

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Fugacity models are used widely to predict the time-dependent behaviors of chemicals in environments containing several media ( e.g. , air, sediment, soil, and water). However, these fugacity models work on the assumption that the concentration of a chemical in each medium is uniform, so they cannot describe the spatial distribution of the chemical. We developed a new fugacity model, termed InPestCFD, incorporating computational fluid dynamics to describe both the time-dependent distribution and the spatial distribution of a chemical in a medium. InPestCFD was used to calculate the behavior of an insecticide released from an aerosol canister in a room. Indoor airflow and aerosol particle behavior were calculated via computational fluid dynamics and using a Lagrangian dispersion model. Transport of the insecticide among media (aerosol particles, air, ceiling, floor, and walls) was calculated using the fugacity model. The time-dependent distributions and spatial distributions of the insecticide in the media agreed well with real measurements.

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Indoor Behavior and Risk Assessment Following Space Spraying of d-Tetramethrin and d-Resmethrin

Cited by 3 publications

References 0 publications

Clarifying Behavior of Prallethrin Evaporated from an Electric Vaporizer on the Floor and Estimating Associated Dermal Exposure

Clarifying Behavior of Prallethrin Evaporated from an Electric Vaporizer on the Floor and Estimating Associated Dermal Exposure

Development of the Simulation Model InPest for Prediction of the Indoor Behavior of Pesticides

Fugacity model incorporating computational fluid dynamics for analyzing the behavior of an insecticide sprayed indoors

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