Spray Drift from a Conventional Axial Fan Airblast Sprayer in a Modern Orchard Work Environment

Abstract

Pesticide spray drift represents an important cause of crop damage and farmworker illness, especially among orchard workers. We drew upon exposure characteristics from known human illness cases to design a series of six spray trials that measured drift from a conventional axial fan airblast sprayer operating in a modern orchard work environment. Polyester line drift samples (n = 270; 45 per trial) were suspended on 15 vertical masts downwind of foliar applications of zinc, molybdenum, and copper micronutrient tracers. Samples were analyzed using inductively coupled plasma mass spectrometry and resulting masses were normalized by sprayer tank mix concentration to create tracer-based drift volume levels. Mixed-effects modeling described these levels in the context of spatial variability and buffers designed to protect workers from drift exposure. Field-based measurements showed evidence of drift up to 52 m downwind, which is approximately 1.7 times greater than the 30 m (100 ft) ‘Application Exclusion Zone’ defined for airblast sprayers by the United States Environmental Protection Agency Worker Protection Standard. When stratified by near (5 m), mid (26 m), and far (52 m) distances, geometric means and standard deviations for drift levels were 257 (1.8), 52 (2.0), and 20 (2.3) µl, respectively. Fixed effect model coefficients showed that higher wind speed [0.53; 95% confidence interval (CI): 0.35, 0.70] and sampling height (0.16; 95% CI: 0.11, 0.20) were positively associated with drift; increasing downwind distance (−0.05; 95% CI: −0.06, −0.04) was negatively associated with drift. Random effects showed large within-location variability, but relatively few systematic changes for individual locations across spray trials after accounting for wind speed, height, and distance. Our study findings demonstrate that buffers may offer drift exposure protection to orchard workers from airblast spraying. Variables such as orchard architecture, sampling height, and wind speed should be included in the evaluation and mitigation of risks from drift exposure. Data from our study may prove useful for estimating potential exposure and validating orchard-based bystander exposure models.

Development and Field Evaluation of a Spray Drift Risk Assessment Tool for Vineyard Spraying Application

“…Fox et al [77], in experiments on apple trees, found that deposits on floss decreased with height at 7.5 m distance downwind, but were more uniform across all heights at 15, 30, and 60 m downwind. Kasner et al [78] reported that the distance from sprayed area, the height above ground, and the wind speed were significantly associated with drift level. Grella et al [64] found a good significant relationship between airborne drift and wind speed variables, especially for the maximum and mean wind speed.…”

Advancing Sustainability in Tree Crop Pest Management: Refining Spray Application Rate with a Laser-guided Variable-rate Sprayer in Apple Orchards

“…Conventional air-assisted (''airblast'') sprayers are the typical choice for pesticide application in orchards and nurseries. Airassisted sprayers are typically used to spray an entire farm at a constant rate (i.e., a set number of liters per hectare), regardless of variation in tree size or canopy characteristics (Hong et al, 2018), and these have been repeatedly shown to have considerable losses due to off-target spray and drift (Kasner et al, 2018;Nuyttens et al, 2011). In a comparison between total estimated leaf target and actual spray deposition in an orchard, 43% of the total amount sprayed by a traditional axial sprayer was applied to the foliage (Duga et al, 2015).…”

Analisis Molekular dan Karakteristik Hidrogen Sianida (HCN)

“…Asam sianida akan larut dalam air (109; 110) , senyawa ini didalam air akanmembentuk ion CNdan ion H + .Senyawa dengan rumus kimia HCN cairan tak bewarna dan sangat beracun. Asam sianida memiliki bentuk molekul (115) linear (116)(117)(118)(119)(120) dengan momen dipol (121) Densitas (94; 125; 126) disebut juga dengan kerapatan merupakan massa per satuan volume suatu zat (211)(212)(213) pada suhu (127; 128) tertentu dan tidak hanya ditentukan gaya interaksi antar molekul (231)(232)(233)(234)(235) .Senyawa asam sianida memiliki sifat melarut sempurna pada air , dan sedikit larut dalam etanol. Ada beberapa faktor yang memengaruhi kelarutan suatu senyawa diantaranya sifat dari zat terlarut (solute) (139)(140)(141)(142)(143) dan pelarut (144) (solvent) (94; 129; 132; 145; 146) dimana zat terlarut yang bersifat polar (214)(215)(216) akan mudah larut dalam solvent (243)(244)(245)(246) atau yang disebut pelarut yang bersifat polar, begitupun sebaliknya, disini berlaku asas like dissolve like.…”