A new tool for laboratory studies on volatilization: Extension of applicability of the photovolatility chamber

✍ Scribed by Andre Wolters; Thomas Kromer; Volker Linnemann; Andreas Schäffer; Harry Vereecken

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 171 KB
• Volume: 22
• Category: Article
• ISSN: 0730-7268
• DOI: 10.1002/etc.5620220417

✦ Synopsis

Abstract

Volatilization from soil and plant surfaces after application is an important source of pesticide residues to the atmosphere. The laboratory photovolatility chamber allows the simultaneous measurement of volatilization and photodegradation of ^14^C‐labeled pesticides under controlled climatic conditions. Both continuous air sampling, which quantifies volatile organic compounds and ^14^CO~2~ separately, and the detection of surface‐located residues allow for a mass balance of radioactivity. The setup of the photo‐volatility chamber was optimized, and additional sensors were installed to characterize the influence of soil moisture, soil temperature, and evaporation on volatilization. The modified flow profile in the glass dome of the chamber arising from the use of a highperformance metal bellows pump was measured. Diminished air velocity near the soil surface and a wind velocity of 0.2 m/s in 3 cm height allowed the requirements of the German guideline on assessing pesticide volatilization for registration purposes to be fulfilled. Determination of soil moisture profiles of the upper soil layer illustrated that defined water content in the soil up to a depth of 4 cm could be achieved by water saturation of air. Cumulative volatilization of [phenyl‐UL‐^14^C]parathion‐methyl ranged from 2.4% under dry conditions to 32.9% under moist conditions and revealed the clear dependence of volatilization on the water content in the top layer.