Diazinon

CAS RN:333-41-5

Volatilization

About 50% of diazinon was lost from treated rice plants within 9 days through volatilization from paddy water & transpiration from leaves. Less than 10% of radioactivity remained in plants as parent cmpd.
The Henry's Law constant for diazinon has been measured as 1.17X10-7 atm-cu m/mole at 23 deg C(1) and 6.25X10-8 atm-cu m/mole at 25 deg C(2). These Henry's Law constants indicate that diazinon is expected to be essentially nonvolatile from water surfaces(3). Diazinon is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 9.0X10-5 mm Hg(4). The percent of applied diazinon which evaporated from soil in a lysimeter experiment was 0.5%/week(5). Diazinon was given a vaporization from soil index of 3.0 (3.5-6.5 kg/ha/yr, or more)(6). A reported measured cumulative volatilization of diazinon from a fallow soil was only 0.13% of applied dose(7).
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed