Pesticide dispersion by spraying under tropical conditions

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Pesticides, food contaminants, and agricultural wastes, 2017-12, Vol.52 (12), p.843-849
• Main Authors: Langenbach, Tomaz, Mano, Denise, Campos, Maize M., Cunha, Alessandra L.M.C., De Campos, Tácio M.P.
• Format: Article
• Language: English
• Subjects: 4-Aminobenzoic Acid - analysis; Agricultural equipment; Agriculture - methods; Agrochemicals; Air Pollutants - analysis; Air pollution; Air Pollution - analysis; Air pollution measurements; Air temperature; Brazil; Climatic conditions; Dispersion; Environmental Monitoring; Field tests; Filters; Fluorescence; fluorescence tracer; Gravitation; Gravity; Guava; Humidity; Membranes; Orchards; para-Aminobenzoic acid; Pesticide pollution; pesticide pulverization; Pesticides; Pesticides - analysis; Pollution; Pollution control; Psidium; Shaking; Soils; Spraying; Sprays; Tropical Climate; Water pollution; Water purification; Water tanks; Wind
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601234.2017.1359040

Pesticide air pollution by spraying was evaluated under different temperature, humidity and wind climatic conditions in Brazil. Field experiments were performed with application towards the soil and in guava orchards, where spray dispersion was monitored by adding p-aminobenzoic acid (PABA), a fluorescent substance, as a tracer to the water contained in the spray tanks. Samples were collected with filter membranes (Whatman 180025), and the PABA was extracted from the filters by shaking with water in a Petri dish and measured in a spectrofluorometer. A spray aimed towards the soil with filters positioned on the ground and hung at different heights did not show different upward dispersion as observed when lateral pulverization was conducted. In this case, a tractor with a sprayer moved through a 3 m high and 6 m wide frame with filter membranes mounted at 60 cm intervals. Spray dispersion patterns were modified by guava leaf resistance. No influence of temperature and humidity was observed in this short-lived spraying process. Nevertheless, wind drift can occur during airborne dispersion and is an important pesticide pollution source which requires control. Droplets with PABA powered by assisted spraying upwards returned to the ground by gravity and, therefore, did not constitute a vertical source of atmospheric pollution.