A case study of molinate application in a Portuguese rice field: herbicide dissipation and proposal of a clean-up methodology.
This study was designed to monitor molinate losses in surface and underground waters during Ordram application in a rice field situated in central Portugal. Water samples were collected from different sites, before, during and about one month and a half after Ordram application. Molinate quantification was based on a solid-phase microextraction (SPME) method followed by gas chromatography with flame photometric detector (GC-FPD) analysis, and led to the conclusion that the herbicide was dissipated in the environment, reaching levels as high as 3.9 microgl(-1) in underground water and 15.8 microgl(-1) in the river receiving tail waters. The feasibility of the application of treatment methodologies based on adsorption or biodegradation as processes to remove molinate from real-world waters was assessed. These methods seem suitable to reduce molinate concentrations to values in the range of the legally recommended limits (<0.5 microgl(-1)).
Castro
Marisa
M
Escola Superior de Biotecnologia, R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
Silva-Ferreira
António C
AC
Manaia
Célia M
CM
Nunes
Olga C
OC
D001381:Azepines / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002849:Chromatography, Gas; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D005618:Fresh Water; D006540:Herbicides / Q000737:chemistry*; D011174:Portugal; D012989:Soil Pollutants / Q000032:analysis*; D013859:Thiocarbamates / Q000737:chemistry*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
D001381:Azepines; D006540:Herbicides; D012989:Soil Pollutants; D013859:Thiocarbamates; D014874:Water Pollutants, Chemical; C009821:molinate