Dissipation of the herbicide oxyfluorfen in subtropical soils and its potential to contaminate groundwater.
The dissipation and mobility of the herbicide oxyfluorfen (2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether) in field soil of Taiwan were investigated in the laboratory with six tea garden soils. The dissipation coefficients of oxyfluorfen in soils of different moisture content (30%, 60%, and 90% of soil field capacity) and soil temperature (10 degrees C, 25 degrees C, and 40 degrees C) were studied. Results indicate that the half-life of oxyfluorfen ranged from 72 to 160 days for six tea garden soils. It was found that if the temperature is high, the dissipation rate is rapid, and there is almost no dissipation at 10 degrees C. Possible contamination of groundwater by the herbicide oxyfluorfen was assessed using the behavior assessment model and the groundwater pollution-potential (GWP) model. The results obtained after evaluating the residue and travel time using the GWP model illustrated that oxyfluorfen is not very mobile in soil and may not contaminate groundwater under normal conditions. But in the case of soil of extremely low organic carbon content and coarse texture, oxyfluorfen has the potential to contaminate groundwater less than 3m deep.
Yen
Jui-Hung
JH
Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan.
Sheu
Wey-Shin
WS
Wang
Yei-Shung
YS
D004784:Environmental Monitoring; D006207:Half-Life; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides / Q000737:chemistry*; D008962:Models, Theoretical; D010316:Particle Size; D010647:Phenyl Ethers / Q000737:chemistry*; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis*; D014329:Tropical Climate; D014872:Water Movements; D014873:Water Pollutants / Q000032:analysis*
D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D010647:Phenyl Ethers; D012987:Soil; D012989:Soil Pollutants; D014873:Water Pollutants; C016027:oxyfluorofen